Chapter 23: Cervical Spine Injuries in Children

William C. Warner, Jr.; Daniel J. Hedequist

Chapter Outline

Cervical Spine Injury

Cervical spine fractures in children are rare, accounting for only 1% of pediatric fractures and 2% of all spinal injuries.7,10,105,115,116,135,141,157,171,220,252,281 The incidence is estimated to be 7.41 in 100,000 per year191; however, that may be misleading because some injuries are not detected or are detected only at autopsy. Aufdermaur16 examined the autopsied spines of 12 juveniles who had spinal injuries. All 12 had cartilage endplates that were separated from the vertebral bodies in the zone of columnar and calcified cartilage, similar to a Salter–Harris type I fracture, although clinically and radiographically, a fracture was suggested in only one patient. Only radiographs at autopsy showed the disruption, represented by a small gap and apparent widening of the intervertebral space.16 
Cervical spine injuries in children younger than 8 years of age occur in the upper cervical spine, whereas older children and adolescents tend to have fractures involving either the upper or lower cervical spine.219,221,222 The upper cervical spine in children is more prone to injury because of the anatomic and biomechanical properties of the immature spine.313,314 The immature spine is hypermobile because of ligamentous laxity, and the facet joints are oriented in a more horizontal position; both of these properties predispose children to more forward translation. Younger children also have a relatively large head compared to the body, which changes the fulcrum of motion of the upper cervical spine. All of these factors predispose younger children to injuries of the upper cervical spine; with age, the anatomic changes lead to an increased prevalence of lower cervical spine injuries. 
Cervical spine injuries associated with neurologic deficits are infrequent in children, and when incomplete there tends to be a better prognosis for recovery in children than in adults.22,60,75,76,212,298,306 Complete neurologic deficits, regardless of patient age, tend to have a poor prognosis for any recovery and may be indicative of the severity and magnitude of injury.79,158,208,230 Death from cervical spine injuries tends to be related to the level of injury and the associated injuries. Higher cervical spine injuries (e.g., atlantooccipital dislocation) in younger children are associated with the highest mortality rate.26,215,216 Children with significant cervical spine injuries also may have associated severe head injuries, leading to an increase in mortality. In a study of 61 pediatric deaths related to spinal cord injuries, 89% of fatalities occurred at the scene, and most were related to high cervical cord injuries in patients who had sustained multiple injuries.119 

Assessment of Cervical Spine Injury

Mechanisms of Injury for Cervical Spine

The mechanism of injury in the cervical spine varies with age. Infants are at risk during birth and early development because of their lack of head control. Most cervical spine injuries in infants not related to birth trauma are caused by child abuse and often involve the spinal cord.16 In young children, most cervical spine injuries result from motor vehicle accidents or being struck by a vehicle, although injuries have been reported after seemingly low-energy falls from heights less than 5 ft.32,111,197 As children become adolescents, the prevalence of sporting injuries increases as does the prevalence of athletic-related spinal cord injury without radiographic abnormality (SCIWORA).42,162 

Associated Injuries with Cervical Spine

Patients with suspected cervical spine injuries need to be thoroughly evaluated for other injuries. Facial injuries as well as traumatic brain injuries are commonly seen with cervical spine injuries, due to the anatomical proximity of these body regions. Vigilance must be high for noncontiguous spine fractures, as well as other orthopedic injuries. Inconsolable children need particular attention, with a thorough search for noncontiguous spine fractures or other associated injuries. 
Spinal Cord Injury
Careful radiographic evaluation is helpful in the workup of these patients. MRI may show a spinal cord lesion that often is some distance from the vertebral column injury. As many as 5% to 10% of children with spinal cord injuries have normal radiographic results.115,132 
Spinal cord injuries are rare in children. Ranjith et al.241 reviewed spinal injuries at the Toronto Hospital for Sick Children over 15 years and found that children constituted a small percentage of the patients with acquired quadriplegia or paraplegia. He found that paraplegia was three times more common than quadriplegia. When a spinal cord injury is suspected, the neurologic examination must be complete and meticulous. Several examinations of sensory and motor function may be necessary. 
Spinal column and spinal cord injury can occur during birth, especially during a breech delivery.168,211 Injuries associated with breech delivery usually are in the lower cervical spine or upper thoracic spine and are thought to result from traction, whereas injuries associated with cephalic delivery usually occur in the upper cervical spine and are thought to result from rotation. Skeletal spine injury from obstetric trauma is probably underreported because the infantile spine is largely cartilaginous and difficult to evaluate with radiographs, especially if the injury is through the cartilage or cartilage–bone interface.16 A cervical spine injury should be considered in an infant who is floppy at birth, especially after a difficult delivery. Flaccid paralysis, with areflexia, usually is followed by a typical pattern of hyperreflexia once spinal cord shock is over. Brachial plexus palsy also may be present after a difficult delivery and warrants cervical spine radiographs and an MRI. It is unclear whether cesarean section reduces spinal injury in neonates179; however, Bresnan and Abroms38 noted that neck hyperextension in utero (star-gazing fetus) in breech presentations is likely to result in an estimated 25% incidence of spinal cord injury with vaginal delivery and can be prevented by cesarean section delivery. 
Immature neck musculature in infants and toddlers increases the risk for cervical spine injury. Distraction-type injuries to the upper cervical spine have been reported in infants in forward-facing car seats. During sudden deceleration maneuvers, the head continues forward while the remainder of the body is strapped in the car seat, resulting in injury.59,108 Child abuse is probably one of the most frequent causes of spinal injury in infants. Swischuk288 in 1969 and Caffey50 in 1974 described a form of child abuse they termed the shaken baby syndrome. This whiplash type stress can cause not only fracture to the spinal column and spinal cord injury, but intracranial and intraocular hemorrhages as well. The cerebral and spinal insult can result in death or retardation and permanent visual and hearing defects. In autopsy studies, Shulman et al.273 found atlantooccipital and axial dislocations, and Tawbin290 found a 10% incidence of brain and spinal injuries. 
Spinal Cord Injury without Radiographic Abnormality (SCIWORA)
SCIWORA, a syndrome first brought to the attention of the medical community by Pang and Wilberger,220 is unique to children. This condition is defined as a spinal cord injury in a patient with no visible fracture or dislocation on plain radiographs, tomograms, or CT scans. 
A complete or incomplete spinal cord lesion may be present, and the injury usually results from severe flexion or distraction of the cervical spine. SCIWORA is believed to occur because the spinal column (vertebrae and disk space) in children is more elastic than the spinal cord and can undergo considerable deformation without being disrupted.46,291 The spinal column can elongate up to 2 in without disruption, whereas the spinal cord ruptures with only a quarter-inch of elongation. 
SCIWORA also may represent an ischemic injury in some patients, although most are believed to be due to a distraction-type injury in which the spinal cord has not tolerated the degree of distraction but the bony ligamentous elements have not failed. Aufdermaur16 suggested another possibility: a fracture through a pediatric vertebral endplate reduces spontaneously (much like a Salter–Harris type I fracture), giving a normal radiograph appearance, although the initial displacement could have caused spinal cord injury. 
SCIWORA abnormalities are more common in children under 8 years of age than in older children,220,228,252,304 perhaps because of predisposing factors such as cervical spine hypermobility, ligamentous laxity, and an immature vascular supply to the spinal cord. The reported incidence of this condition varies from 7% to 66% of patients with cervical spine injuries.219,220,321 
Delayed onset of neurologic symptoms has been reported in as many as 52% of patients in some series.194,220 Pang and Pollack219 reported 15 patients who had delayed paralysis after their injuries. Nine had transient warning signs such as paresthesia or subjective paralysis. In all patients with delayed onset of paralysis, the spine had not been immobilized after the initial trauma, and all were neurologically normal before the second event. This underlines the importance of diligent immobilization of a suspected spinal cord injury in a child. Approximately half of the young children with SCIWORA in reported series had complete spinal cord injuries, whereas the older children usually had incomplete neurologic deficit injuries that involved the subaxial cervical spine.12,17,121,194 

Signs and Symptoms of Cervical Spine Injuries

The most common presenting symptom in patients with cervical spine injuries is pain localized to the cervical region. Other complaints, such as headache, inability to move the neck, subjective feelings of instability, and neurologic symptoms, all warrant complete evaluation. Infants may present with unexplained respiratory distress, motor weakness, or hypotonia, which warrant further evaluation. Patients with head and neck trauma, distraction injuries, or altered levels of consciousness are at high risk for a cervical spine injury and need to be thoroughly evaluated before obtaining cervical spine clearance.42 The presence of an occult cervical spine injury in an uncooperative or obtunded patient needs to be considered because of the frequency of SCIWORA in the pediatric population.220,252 

Imaging and Other Diagnostic Studies for Cervical Spine Injuries

Plain Radiographs
Plain radiographs are the standard first step for evaluating the cervical spine in children.207 There currently is no consensus regarding whether or not all pediatric trauma patients require cervical spine films. The presence of tenderness and a distraction injury are the most common clinical presentations of a cervical spine injury.302 While some studies have shown that plain radiographs are of low yield in patients without evidence of specific physical findings, the burden remains on the treating physician to clear the cervical spine.9,69,169,175 Clearly, patients with tenderness, distraction injuries, neurologic deficits, head and neck trauma, and altered levels of consciousness need to have a complete set of cervical spine radiographs. Initial radiographs should include an anteroposterior view, open-mouth odontoid view, and lateral view of the cervical spine. Patients who are deemed unstable in the emergency room and are not able to tolerate multiple radiographs should have a cross-table lateral view of the cervical spine until further radiographs can be taken.40 The false-negative rates for a single cross-table radiograph have been reported to be 23% to 26%, indicating that complete radiographs are necessary when the patient is stable.19,266 
Flexion and extension radiographs may further aid the evaluation of the cervical spine, but these views are unlikely to be abnormal when standard views show no abnormalities. These views are helpful, however, in ruling out acute ligamentous injury.240 We recommend flexion and extension views in an alert patient with midline tenderness who has normal plain films of the cervical spine. These views should be taken only with a cooperative and alert child; they should not be used in obtunded or uncooperative patients, nor should they be done by manually placing the child in a position of flexion and extension. 
Evaluation of cervical spine radiographs should proceed with a knowledge of the anatomic ossification centers and variations that occur in children. Each vertebral level should be systematically evaluated, as should the overall alignment of the cervical spine with respect to the anterior and posterior aspects of the vertebral bodies, the spinolaminar line, and the interspinous distances. The absence of cervical lordosis, an increase in the prevertebral soft tissue space, and subluxation of C2 on C3 are all anatomic variations that may be normal in children.50 Ossification centers also may be confused with fractures, most commonly in evaluation of the dens. The presence of a synchondrosis at the base of the odontoid can be distinguished from a fracture based on the age of the patient and the location of synchondrosis well below the facet joints. Knowledge of these normal variants is useful in evaluating plain radiographs of the cervical spine in children (Table 23-1). 
Table 23-1
Normal Ossification Centers and Anomalies Frequently Confused with Injury
Avulsion Fracture
Apical ossification center of the odontoid. Secondary ossification centers at the tips of the transverse and spinous processes
Fracture
Persistence of the synchondrosis at the base of the odontoid
Apparent anterior wedging of a young child's vertebral body
Normal posterior angulation of the odontoid seen in 4% of normal children
Instability
Pseudosubluxation of C2–C3
Incomplete ossification, especially of the odontoid process, with apparent superior subluxation of the anterior arch of C1
Absence of the ossification center of the anterior arch of C1 in the first year of life may suggest posterior displacement of C1 on the odontoid
Increase in the atlanto–dens interval of up to 4.5 mm
Miscellaneous
Physiologic variations in the width of the prevertebral soft tissue due to crying misinterpreted as swelling due to edema or hemorrhage
Overlying structures such as ears, braided hair, teeth, or hyoid bone. Plastic rivets used in modern emergency cervical immobilization collars can simulate fracture line
Horizontally placed facets in the younger child, creating the illusion of a pillar fracture
Congenital anomalies such as os odontoideum, spina bifida, and congenital fusion or hemivertebrae
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Radiographic Evaluation of Specific Areas of the Spine
Atlantooccipital Junction
The atlantooccipital interval remains the most difficult to assess for abnormalities, partly because of the difficulty in obtaining quality radiographs and partly because of the lack of discrete and reproducible landmarks. The distance between the occipital condyles and the facet joints of the atlas should be less than 5 mm; any distance of more than this suggests an atlantooccipital disruption.70,231 The foramen magnum and its relationship to the atlas also are useful in detecting injuries of the atlantooccipital region. The anterior cortical margin of the foramen magnum is termed the basion, whereas the posterior cortical margin of the foramen magnum is termed the opisthion. The distance between the basion and the tip of the dens should be less than 12 mm as measured on a lateral radiograph.44 The Powers ratio (Fig. 23-1) is used to assess the position of the skull base relative to the atlas and is another way of evaluating the atlantooccipital region. To determine this ratio, a line is drawn from the basion to the anterior cortex of the posterior arch of C1, and this distance is divided by the distance of a line drawn from the opisthion to the posterior cortex of the anterior arch of C1. The value should be between 0.7 and 1; a higher value indicates anterior subluxation of the atlantooccipital joint and a lower value indicates a posterior subluxation. The problem lies in the fact that the basion is not always visible on plain radiographs. The Wackenheim line, which is drawn along the posterior aspect of the clivus, probably is the most easily identified line to determine disruption of the atlantooccipital joint. If the line does not intersect the tip of the odontoid tangentially and if this line is displaced anteriorly or posteriorly, disruption or increased laxity about the atlantooccipital joint should be suspected. 
Figure 23-1
The Powers ratio is determined by drawing a line from the basion (B) to the posterior arch of the atlas (C) and a second line from the opisthion (O) to the anterior arch of the atlas (A).
 
The length of the line BC is divided by the length of the line OA, producing the Powers ratio.
 
(From Lebwohl NH, Eismont FJ. Cervical spine injuries in children. In: Weinstein SL, ed. The Pediatric Spine: Principles and Practice. New York, NY: Raven, 1994, with permission.)
The length of the line BC is divided by the length of the line OA, producing the Powers ratio.
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Figure 23-1
The Powers ratio is determined by drawing a line from the basion (B) to the posterior arch of the atlas (C) and a second line from the opisthion (O) to the anterior arch of the atlas (A).
The length of the line BC is divided by the length of the line OA, producing the Powers ratio.
(From Lebwohl NH, Eismont FJ. Cervical spine injuries in children. In: Weinstein SL, ed. The Pediatric Spine: Principles and Practice. New York, NY: Raven, 1994, with permission.)
The length of the line BC is divided by the length of the line OA, producing the Powers ratio.
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Atlantoaxial Joint
The atlanto–dens interval (ADI) and the space available for the spinal canal are two useful measurements for evaluation of the atlantoaxial joint (Fig. 23-2). The ADI in a child is considered normal up to 4.5 mm, partly because the unossified cartilage of the odontoid, which is not seen on plain films, gives an apparent increase in the interval. At the level of the atlantoaxial joint, the space taken up is broken into Steel's rule of thirds: one-third is occupied by the odontoid, one-third by the spinal cord, and one-third is free space available for the cord. These intervals also are easily measured on flexion and extension views and are helpful in determining instability. In children, extension views give the appearance of subluxation of the anterior portion of the atlas over the unossified dens, but this represents a pseudosubluxation and not instability.52,66 
Figure 23-2
The ADI and the space available for cord are used in determining atlantoaxial instability.
 
The Wackenheim clivus-canal line is used to determine atlantooccipital injury, while the McRae and McGregor lines are used in the measurement of basilar impression.
 
(modified from Copley LA, Dormans JP. Cervical spine disorders in infants and children. J Am Acad Orthop Surg. 1998; 6:204–214.)
The Wackenheim clivus-canal line is used to determine atlantooccipital injury, while the McRae and McGregor lines are used in the measurement of basilar impression.
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Figure 23-2
The ADI and the space available for cord are used in determining atlantoaxial instability.
The Wackenheim clivus-canal line is used to determine atlantooccipital injury, while the McRae and McGregor lines are used in the measurement of basilar impression.
(modified from Copley LA, Dormans JP. Cervical spine disorders in infants and children. J Am Acad Orthop Surg. 1998; 6:204–214.)
The Wackenheim clivus-canal line is used to determine atlantooccipital injury, while the McRae and McGregor lines are used in the measurement of basilar impression.
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Upper Cervical Spine
Anterior displacement of one vertebral body on another may or may not indicate a true bony or ligamentous injury. Displacement of less than 3 mm at one level is a common anatomic variant in children at the levels of C2 to C3 and C3 to C4. This displacement is seen on flexion radiographs and reduces in extension. The posterior line of Swischuk and Rowe287 has been described to differentiate pathologic subluxation from normal anatomic variation; this line is drawn from the anterior cortex of the spinous process of C1 to the spinous process of C3 (Fig. 23-3). The anterior cortex of the spinous process of C2 should lie within 3 mm of this line; if the distance is more than this, a true subluxation should be suspected (Fig. 23-4). Widening of the spinous processes between C1 and C2 of more than 10 mm also is indicative of a ligamentous injury and should be evaluated by further imaging studies.3 
Figure 23-3
The spinolaminar line (Swischuk line) is used to determine the presence of pseudosubluxation of C2 on C3.
 
(From Copley LA, Dormans JP. Cervical spine disorders in infants and children. J Am Acad Orthop Surg. 1998; 6:201–214, with permission.)
(From 


Copley LA,

Dormans JP
.
Cervical spine disorders in infants and children.
J Am Acad Orthop Surg.
1998;
6:201–214, with permission.)
View Original | Slide (.ppt)
Figure 23-3
The spinolaminar line (Swischuk line) is used to determine the presence of pseudosubluxation of C2 on C3.
(From Copley LA, Dormans JP. Cervical spine disorders in infants and children. J Am Acad Orthop Surg. 1998; 6:201–214, with permission.)
(From 


Copley LA,

Dormans JP
.
Cervical spine disorders in infants and children.
J Am Acad Orthop Surg.
1998;
6:201–214, with permission.)
View Original | Slide (.ppt)
X
Figure 23-4
 
A: Pseudosubluxation of C2 on C3. In flexion, the posterior element of C2 should normally align itself with the posterior elements C1 and C3. The relationship of the body of C2 with the body of C3 gives the appearance of subluxation; however, the alignment of the posterior elements of C1 to C3 confirms pseudosubluxation. B: True subluxation.
A: Pseudosubluxation of C2 on C3. In flexion, the posterior element of C2 should normally align itself with the posterior elements C1 and C3. The relationship of the body of C2 with the body of C3 gives the appearance of subluxation; however, the alignment of the posterior elements of C1 to C3 confirms pseudosubluxation. B: True subluxation.
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Figure 23-4
A: Pseudosubluxation of C2 on C3. In flexion, the posterior element of C2 should normally align itself with the posterior elements C1 and C3. The relationship of the body of C2 with the body of C3 gives the appearance of subluxation; however, the alignment of the posterior elements of C1 to C3 confirms pseudosubluxation. B: True subluxation.
A: Pseudosubluxation of C2 on C3. In flexion, the posterior element of C2 should normally align itself with the posterior elements C1 and C3. The relationship of the body of C2 with the body of C3 gives the appearance of subluxation; however, the alignment of the posterior elements of C1 to C3 confirms pseudosubluxation. B: True subluxation.
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Lower Cervical Spine
Lateral radiographs of the cervical spine should be evaluated for overall alignment. The overall alignment can be evaluated by the continuous lines formed by the line adjoining the spinous processes, the spinolaminar line, and the lines adjoining the posterior and anterior vertebral bodies (Fig. 23-5). These lines should all be smooth and continuous with no evidence of vertebral translation at any level. Loss of normal cervical lordosis may be normal in children, but there should be no associated translation at any level.304 The interspinous distance at each level should be evaluated and should be no more than 1.5 times the distance at adjacent levels; if this ratio is greater, an injury should be suspected. There are calculated norms for the interspinous distances in children, and any value greater than two standard deviations above normal is indicative of a ligamentous injury.168 The measurement of soft tissue spaces is important in evaluating any evidence of swelling or hemorrhage, which may be associated with an occult injury. The normal retropharyngeal soft tissue space should be less than 6 mm at C3 and less than 14 mm at C6. These spaces may be increased in children without an injury who are crying at the time of the radiograph, because the attachment of the pharynx to the hyoid bone results in its forward displacement with crying, producing an apparent increase in the width of these spaces. These radiographs must be taken with the patient quiet and repeated if there is any doubt. 
Figure 23-5
Normal relationships in the lateral cervical spine: 1, spinous processes; 2, spinolaminar line; 3, posterior vertebral body line; 4, anterior vertebral body line.
 
(From Copley LA, Dormans JP. Cervical spine disorders in infants and children. J Am Acad Orthop Surg. 1998; 6:204–214, with permission.)
(From 


Copley LA,

Dormans JP
.
Cervical spine disorders in infants and children.
J Am Acad Orthop Surg.
1998;
6:204–214, with permission.)
View Original | Slide (.ppt)
Figure 23-5
Normal relationships in the lateral cervical spine: 1, spinous processes; 2, spinolaminar line; 3, posterior vertebral body line; 4, anterior vertebral body line.
(From Copley LA, Dormans JP. Cervical spine disorders in infants and children. J Am Acad Orthop Surg. 1998; 6:204–214, with permission.)
(From 


Copley LA,

Dormans JP
.
Cervical spine disorders in infants and children.
J Am Acad Orthop Surg.
1998;
6:204–214, with permission.)
View Original | Slide (.ppt)
X
Special Imaging Studies
Most cervical spine injuries in children are detected by plain radiographs.10 Most ligamentous injuries can be identified on flexion and extension views of the cervical spine in a cooperative and alert patient. The roles of computed tomography (CT) imaging and magnetic resonance imaging (MRI) continue to evolve in the evaluation of trauma patients.55 
Plain radiographs remain the standard for initial evaluation of the pediatric cervical spine; CT imaging as an initial diagnostic study is associated with an increase in radiation with no demonstrable benefit over plain radiographs.2 However, when CT imaging is used in children, a few salient points should be kept in mind. First, the proportion of a child's head to his or her body is greater than that of an adult, so care must be taken not to position the head in flexion to obtain the scan, which could potentiate any occult fracture not seen on plain films (Fig. 23-6). Second, the radiation doses for CT imaging are significantly higher than for plain radiographs, and CT protocols for children should be used to limit the amount of radiation. Although axial views are standard, coronal and sagittal formatted images and three-dimensional reconstruction views provide improved anatomic detail of the spine and can be obtained without any additional radiation to the patient.129,184 In patients with head injuries, the cervical spine can be included in the CT image of the head to reduce the number of plain films necessary to rule out an occult spinal injury.155 
Figure 23-6
Anterior translation with patient on a spine board.
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MRI has become increasingly useful in evaluating pediatric patients with suspected cervical spine injuries (Fig. 23-7), especially for ruling out ligamentous injuries in patients who cannot cooperate with flexion and extension views.93 The advantages of an early MRI are the ability to allow mobilization if no injury is present and the early detection of an unrecognized spinal fracture to allow proper treatment. MRI also is useful in evaluating patients with SCIWORA. MR angiography (MRA) has replaced standard arteriography for evaluation of the vertebral arteries in patients with upper cervical spine injuries who have suspected arterial injuries.224 MRI also remains the best imaging modality for evaluating injuries of the intervertebral disks and is especially useful to detect disk herniation in adolescent patients with facet joint injuries that may require operative reduction. 
Figure 23-7
MRI depicts injury to the cervical cord and upper cervical spine.
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Classification of Cervical Spine Injuries

There is currently no fracture classification for pediatric cervical spine injuries. Fractures are defined by the level of injury as well as whether there is an associated bony injury or ligamentous injury. The presence of ligamentous injuries is more common in younger children whereas subaxial cervical injuries are more common toward skeletal maturity, and fractures may then be classified using adult fracture classifications. Classifications for specific fractures are discussed later in the chapter. 

Pathoanatomy and Applied Anatomy Relating to Cervical Spine Injury

Understanding the normal growth and development of the cervical spine is essential when treating a child with a suspected cervical spine injury. This will allow the physician to differentiate normal physes or synchondroses from pathologic fractures or ligamentous disruptions and will alert the physician to any possible congenital anomalies that may be mistaken for a fracture. 

Upper Cervical Spine

At birth, the atlas is composed of three ossification centers, one for the body and one for each of the neural arches (Fig. 23-8). In approximately 20% of individuals, the ossification center for the anterior arch is present at birth; in the remainder they appear by 1 year of age. Occasionally, the anterior arch is bifid, and the body may be formed from two centers, or it may fail to completely form. The posterior arches usually fuse by 3 years of age; however, occasionally the posterior synchondrosis between the two arches fails to fuse, resulting in a bifid arch. The neurocentral synchondroses that link the neural arches to the body close by 7 years of age. They are best seen on an open-mouth odontoid view and should not be mistaken for fractures.50 The canal of the atlas is large enough to allow for the rotation that is necessary at this joint as well as some forward translation.52 The vertebral arteries are about 2 cm from the midline and run in a groove on the superior surface of the atlas. This must be remembered during lateral dissection at the occipital–cervical junction. The ring of C1 reaches about normal adult size by 4 years of age.10 
Figure 23-8
Diagram of C1 (atlas).
 
The body (A) is not ossified at birth, and its ossification center appears during the first year of life. The body may fail to develop, and forward extension of neural arches (C) may take its place. Neural arches appear bilaterally about the seventh week (D), and the most anterior portion of the superior articulating surface usually is formed by the body. The synchondrosis of the spinous processes unites by the third year. Union rarely is preceded by the appearance of the secondary center within the synchondrosis. Neurocentral synchondrosis (F) fuses about the seventh year. The ligament surrounding the superior vertebral notch (K) may ossify, especially in later life.
 
(From Bailey DK. Normal cervical spine in infants and children. Radiology. 1952; 59:713–714, with permission.)
The body (A) is not ossified at birth, and its ossification center appears during the first year of life. The body may fail to develop, and forward extension of neural arches (C) may take its place. Neural arches appear bilaterally about the seventh week (D), and the most anterior portion of the superior articulating surface usually is formed by the body. The synchondrosis of the spinous processes unites by the third year. Union rarely is preceded by the appearance of the secondary center within the synchondrosis. Neurocentral synchondrosis (F) fuses about the seventh year. The ligament surrounding the superior vertebral notch (K) may ossify, especially in later life.
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Figure 23-8
Diagram of C1 (atlas).
The body (A) is not ossified at birth, and its ossification center appears during the first year of life. The body may fail to develop, and forward extension of neural arches (C) may take its place. Neural arches appear bilaterally about the seventh week (D), and the most anterior portion of the superior articulating surface usually is formed by the body. The synchondrosis of the spinous processes unites by the third year. Union rarely is preceded by the appearance of the secondary center within the synchondrosis. Neurocentral synchondrosis (F) fuses about the seventh year. The ligament surrounding the superior vertebral notch (K) may ossify, especially in later life.
(From Bailey DK. Normal cervical spine in infants and children. Radiology. 1952; 59:713–714, with permission.)
The body (A) is not ossified at birth, and its ossification center appears during the first year of life. The body may fail to develop, and forward extension of neural arches (C) may take its place. Neural arches appear bilaterally about the seventh week (D), and the most anterior portion of the superior articulating surface usually is formed by the body. The synchondrosis of the spinous processes unites by the third year. Union rarely is preceded by the appearance of the secondary center within the synchondrosis. Neurocentral synchondrosis (F) fuses about the seventh year. The ligament surrounding the superior vertebral notch (K) may ossify, especially in later life.
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The axis develops from at least four separate ossification centers: one for the dens, one for the body, and two for the neural arches (Fig. 23-9). Between the odontoid and the body of the axis is a synchondrosis or vestigial disk space that often is mistaken for a fracture line. This synchondrosis runs well below the level of the articular processes of the axis and usually fuses at 6 to 7 years of age, although it may persist as a sclerotic line until 11 years of age.52 The most common odontoid fracture pattern in adults and adolescents is transverse and at the level of the articular processes. The normal synchondrosis should not be confused with this fracture; the synchondrosis is more cup-shaped and below the level of the articular processes. After 7 years of age, the synchondrosis should not be present on an open-mouth odontoid view; a fracture should be considered if a lucent line is present after this age. The neural arches of C2 fuse at 3 to 6 years of age; these are seen as vertical lucent lines on the open-mouth odontoid view. Occasionally, the tip of the odontoid is V-shaped (dens bicornum), or a small separate summit ossification center may be present at the tip of the odontoid (ossiculum terminale). An os odontoideum is believed to result from a history of unrecognized trauma. The differentiation between an os odontoideum and the synchondrosis of the body is relatively easy because of their relationships to the level of the C1 to C2 facet (Fig. 23-10). 
Figure 23-9
Diagram of C2 (axis).
 
The body (A) in which one center (occasionally two) appears by the fifth fetal month. Neural arches (C) appear bilaterally by the seventh fetal month. Neural arches fuse (D) posteriorly by the second or third year. Bifid tip (E) of spinous process (occasionally a secondary center is present in each tip). Neurocentral synchondrosis (F) fuses at 3 to 6 years. The inferior epiphyseal ring (G) appears at puberty and fuses at about 25 years of age. The summit ossification center (H) for the odontoid appears at 3 to 6 years and fuses with the odontoid by 12 years. Odontoid (dens) (I). Two separate centers appear by the fifth fetal month and fuse with each other by the seventh fetal month. The synchondrosis between the odontoid and neural arch (I) fuses at 3 to 6 years. Synchondrosis between the odontoid and body (L) fuses at 3 to 6 years. Posterior surface of the body and odontoid (M).
 
(From Bailey DK. Normal cervical spine in infants and children. Radiology. 1952; 59:713–714, with permission.)
The body (A) in which one center (occasionally two) appears by the fifth fetal month. Neural arches (C) appear bilaterally by the seventh fetal month. Neural arches fuse (D) posteriorly by the second or third year. Bifid tip (E) of spinous process (occasionally a secondary center is present in each tip). Neurocentral synchondrosis (F) fuses at 3 to 6 years. The inferior epiphyseal ring (G) appears at puberty and fuses at about 25 years of age. The summit ossification center (H) for the odontoid appears at 3 to 6 years and fuses with the odontoid by 12 years. Odontoid (dens) (I). Two separate centers appear by the fifth fetal month and fuse with each other by the seventh fetal month. The synchondrosis between the odontoid and neural arch (I) fuses at 3 to 6 years. Synchondrosis between the odontoid and body (L) fuses at 3 to 6 years. Posterior surface of the body and odontoid (M).
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Figure 23-9
Diagram of C2 (axis).
The body (A) in which one center (occasionally two) appears by the fifth fetal month. Neural arches (C) appear bilaterally by the seventh fetal month. Neural arches fuse (D) posteriorly by the second or third year. Bifid tip (E) of spinous process (occasionally a secondary center is present in each tip). Neurocentral synchondrosis (F) fuses at 3 to 6 years. The inferior epiphyseal ring (G) appears at puberty and fuses at about 25 years of age. The summit ossification center (H) for the odontoid appears at 3 to 6 years and fuses with the odontoid by 12 years. Odontoid (dens) (I). Two separate centers appear by the fifth fetal month and fuse with each other by the seventh fetal month. The synchondrosis between the odontoid and neural arch (I) fuses at 3 to 6 years. Synchondrosis between the odontoid and body (L) fuses at 3 to 6 years. Posterior surface of the body and odontoid (M).
(From Bailey DK. Normal cervical spine in infants and children. Radiology. 1952; 59:713–714, with permission.)
The body (A) in which one center (occasionally two) appears by the fifth fetal month. Neural arches (C) appear bilaterally by the seventh fetal month. Neural arches fuse (D) posteriorly by the second or third year. Bifid tip (E) of spinous process (occasionally a secondary center is present in each tip). Neurocentral synchondrosis (F) fuses at 3 to 6 years. The inferior epiphyseal ring (G) appears at puberty and fuses at about 25 years of age. The summit ossification center (H) for the odontoid appears at 3 to 6 years and fuses with the odontoid by 12 years. Odontoid (dens) (I). Two separate centers appear by the fifth fetal month and fuse with each other by the seventh fetal month. The synchondrosis between the odontoid and neural arch (I) fuses at 3 to 6 years. Synchondrosis between the odontoid and body (L) fuses at 3 to 6 years. Posterior surface of the body and odontoid (M).
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Figure 23-10
CT scan showing presence of an os odontoideum.
 
Note the position of the os well above the C1 to C2 facets. The scan also shows the vestigial scar of the synchondrosis between the dens and the body below the C1 to C2 facet.
Note the position of the os well above the C1 to C2 facets. The scan also shows the vestigial scar of the synchondrosis between the dens and the body below the C1 to C2 facet.
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Figure 23-10
CT scan showing presence of an os odontoideum.
Note the position of the os well above the C1 to C2 facets. The scan also shows the vestigial scar of the synchondrosis between the dens and the body below the C1 to C2 facet.
Note the position of the os well above the C1 to C2 facets. The scan also shows the vestigial scar of the synchondrosis between the dens and the body below the C1 to C2 facet.
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The arterial supply to the odontoid is derived from the vertebral and carotid arteries. The anterior and posterior ascending arteries arise from the vertebral artery at the level of C3 and ascend anterior and posterior to the odontoid, meeting superiorly to form an apical arcade. These arteries supply small penetrating branches to the body of the axis and the odontoid process. The internal carotid artery gives off cleft perforators that supply the superior portion of the odontoid. This arrangement of arteries and vessels is necessary for embryologic development and anatomic function of the odontoid. The synchondrosis prevents direct vascularization of the odontoid from C2, and vascularization from the blood supply of C1 is not possible because the synovial joint cavity surrounds the odontoid. The formation of an os odontoideum after cervical trauma may be related to this peculiar blood supply (Fig. 23-11). 
Figure 23-11
Blood supply to odontoid: posterior and anterior ascending arteries and apical arcade.
 
(From Schiff DC, Parke WW. The arterial supply of the odontoid process. J Bone Joint Surg Am 1973; 55:1450–1464, with permission.258)
(From 


Schiff DC,

Parke WW
.
The arterial supply of the odontoid process.
J Bone Joint Surg Am
1973;
55:1450–1464, with permission.258)
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Figure 23-11
Blood supply to odontoid: posterior and anterior ascending arteries and apical arcade.
(From Schiff DC, Parke WW. The arterial supply of the odontoid process. J Bone Joint Surg Am 1973; 55:1450–1464, with permission.258)
(From 


Schiff DC,

Parke WW
.
The arterial supply of the odontoid process.
J Bone Joint Surg Am
1973;
55:1450–1464, with permission.258)
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X

Lower Cervical Spine

The third through seventh cervical vertebrae share a similar ossification pattern: a single ossification center for the vertebral body and an ossification center for each neural arch (Fig. 23-12). The neural arch fuses posteriorly between the second and third years, and the neurocentral synchondroses between the neural arches and the vertebral body fuse by 3 to 6 years of age. These vertebrae normally are wedge-shaped until 7 to 8 years of age.16,170,239 The vertebral bodies, neural arches, and pedicles enlarge by periosteal appositional growth, similar to that seen in long bones. By 8 to 10 years of age, a child's spine usually reaches near adult size and characteristics. There are five secondary ossification centers that can remain open until 25 years of age.169 These include one each for the spinous processes, transverse processes, and the ring apophyses about the vertebral endplates. These should not be confused with fractures. 
Figure 23-12
Diagram of typical cervical vertebrae, C3 to C7.
 
The body (A) appears by the fifth fetal month. The anterior (costal) portion of the transverse process (B) may develop from a separate center that appears by the sixth fetal month and joins the arch by the sixth year. Neural arches (C) appear by the seventh to ninth fetal week. The synchondrosis between spinous processes (D) usually unites by the second or third year. Secondary centers for bifid spine (E) appear at puberty and unite with spinous process at 25 years. Neurocentral synchondrosis (F) fuses at 3 to 6 years. Superior and inferior epiphyseal rings (G) appear at puberty and unite with the body at about 25 years. The seventh cervical vertebra differs slightly because of a long, powerful, nonbifid spinous process.
 
(From Bailey DK. Normal cervical spine in infants and children. Radiology. 1952; 59:713–714, with permission.)
The body (A) appears by the fifth fetal month. The anterior (costal) portion of the transverse process (B) may develop from a separate center that appears by the sixth fetal month and joins the arch by the sixth year. Neural arches (C) appear by the seventh to ninth fetal week. The synchondrosis between spinous processes (D) usually unites by the second or third year. Secondary centers for bifid spine (E) appear at puberty and unite with spinous process at 25 years. Neurocentral synchondrosis (F) fuses at 3 to 6 years. Superior and inferior epiphyseal rings (G) appear at puberty and unite with the body at about 25 years. The seventh cervical vertebra differs slightly because of a long, powerful, nonbifid spinous process.
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Figure 23-12
Diagram of typical cervical vertebrae, C3 to C7.
The body (A) appears by the fifth fetal month. The anterior (costal) portion of the transverse process (B) may develop from a separate center that appears by the sixth fetal month and joins the arch by the sixth year. Neural arches (C) appear by the seventh to ninth fetal week. The synchondrosis between spinous processes (D) usually unites by the second or third year. Secondary centers for bifid spine (E) appear at puberty and unite with spinous process at 25 years. Neurocentral synchondrosis (F) fuses at 3 to 6 years. Superior and inferior epiphyseal rings (G) appear at puberty and unite with the body at about 25 years. The seventh cervical vertebra differs slightly because of a long, powerful, nonbifid spinous process.
(From Bailey DK. Normal cervical spine in infants and children. Radiology. 1952; 59:713–714, with permission.)
The body (A) appears by the fifth fetal month. The anterior (costal) portion of the transverse process (B) may develop from a separate center that appears by the sixth fetal month and joins the arch by the sixth year. Neural arches (C) appear by the seventh to ninth fetal week. The synchondrosis between spinous processes (D) usually unites by the second or third year. Secondary centers for bifid spine (E) appear at puberty and unite with spinous process at 25 years. Neurocentral synchondrosis (F) fuses at 3 to 6 years. Superior and inferior epiphyseal rings (G) appear at puberty and unite with the body at about 25 years. The seventh cervical vertebra differs slightly because of a long, powerful, nonbifid spinous process.
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The superior and inferior endplates are firmly bound to the adjacent disk. The junction between the vertebral body and the endplate is similar to a physis of a long bone. The vertebral body is analogous to the metaphysis and the endplate to the physis, where longitudinal growth occurs. The junction between the vertebral body and the endplate has been shown to be weaker than the adjacent vertebral body or disk, which can result in a fracture at the endplate in the area of columnar and calcified cartilage of the growth zone, similar to a Salter–Harris type I fracture of a long bone.16 The inferior end plate may be more susceptible to this injury than the superior endplate because of the mechanical protection afforded by the developing uncinate processes.31 
The facet joints of the cervical spine change in orientation with age. The angle of the C1 to C2 facet is 55 degrees in newborns and increases to 70 degrees at maturity. In the lower cervical spine, the angle of the facet joints is 30 degrees at birth and 60 to 70 degrees at maturity. This may explain why the pediatric cervical spine may be more susceptible to injury from the increased motion or translation allowed by the facet joint orientation. 
Increased ligamentous laxity in young children allows a greater degree of spinal mobility than in adults. Flexion and extension of the spine at C2 to C3 are 50% greater in children between the ages of 3 and 8 years than in adults. The level of the greatest mobility in the cervical spine descends with increasing age. Between 3 and 8 years of age, the most mobile segment is C3 to C4; from 9 to 11 years, C4 to C5 is the most mobile segment, and from 12 to 15 years, C5 to C6 is the most mobile segment.4,231 This explains the tendency for craniocervical injuries in young children. 
Several anomalies of the cervical spine may influence treatment recommendations. The atlas can fail to segment from the skull, a condition called occipitalization of the atlas, and can lead to narrowing of the foramen magnum, neurologic symptoms, and increased stresses to the atlantoaxial articulation, which often causes instability. Failure of fusion of the posterior arch of C1 is not uncommon and should be sought before any procedure that involves C1. Wedge-shaped vertebrae, bifid vertebrae, or a combination of these also can occur. Klippel–Feil syndrome consists of the classic triad of a short neck, low posterior hairline, and severe restriction of motion of the neck from fusion of the cervical vertebrae.134,160 Congenital fusion of the cervical spine may predispose a child to injury from trauma by concentrating stresses in the remaining mobile segments. 
Hensinger et al.133 reported congenital anomalies of the odontoid, including aplasia (complete absence), hypoplasia (partial absence in which there is a stubby piece at the base of the odontoid located above the C1 articulation), and os odontoideum. Os odontoideum consists of a separate ossicle of the odontoid with no connection to the body of C2. The cause may be traumatic. These anomalies also may predispose a child to injury or instability. 

Treatment Options for Cervical Spine Injuries

Initial Management of Patients with Suspected Cervical Spine Injury

The initial management of a child with a suspected cervical spine injury is paramount to avoiding further injury to the cervical spine and spinal cord. The initial management of any child suspected of having a cervical spine injury starts with immobilization in the field. Extraction from an automobile or transport to the hospital may cause damage to the spinal cord in a child with an unstable cervical spine injury if care is not taken to properly immobilize the neck. The immobilization device should allow access to the patient's oropharynx and anterior neck if intubation or tracheostomy becomes necessary. The device should allow splintage of the head and neck to the thorax to minimize further movement. 
The use of backboards in pediatric trauma patients deserves special attention because of the anatomic differences between children and adults. Compared to adults, children have a disproportionately larger head with respect to the body. This anatomic relationship causes a child's cervical spine to be placed in flexion if immobilization is done on a standard backboard. Herzenberg et al.136 reported 10 children under the age of 7 years whose cervical spines had anterior angulation or translation on radiograph when they were placed on a standard backboard. The use of a backboard with a recess so that the head can be lowered into it to obtain a neutral position of the cervical spine is one way to avoid unnecessary flexion. Another is a split-mattress technique in which the body is supported by two mattresses and the head is supported by one mattress, allowing the cervical spine to assume a neutral position. Children younger than 8 years of age should be immobilized on a backboard using one of these techniques (Figs. 23-13 and 23-14).57,213 
Figure 23-13
 
A: Adult immobilized on a standard backboard. B: Young child on a standard backboard. The relatively large head forces the neck into a kyphotic position.
 
(From Herzenberg JE, Hensinger RN, Dedrick DK, et al. Emergency transport and positioning of young children who have an injury of the cervical spine: the standard backboard may be hazardous. J Bone Joint Surg Am. 1989; 71:15–22, with permission.)
A: Adult immobilized on a standard backboard. B: Young child on a standard backboard. The relatively large head forces the neck into a kyphotic position.
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Figure 23-13
A: Adult immobilized on a standard backboard. B: Young child on a standard backboard. The relatively large head forces the neck into a kyphotic position.
(From Herzenberg JE, Hensinger RN, Dedrick DK, et al. Emergency transport and positioning of young children who have an injury of the cervical spine: the standard backboard may be hazardous. J Bone Joint Surg Am. 1989; 71:15–22, with permission.)
A: Adult immobilized on a standard backboard. B: Young child on a standard backboard. The relatively large head forces the neck into a kyphotic position.
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Figure 23-14
 
A: Young child on a modified backboard that has a cutout to the recess of the occiput, obtaining better supine cervical alignment. B: Young child on modified backboard that has a double-mattress pad to raise the chest, obtaining better supine cervical alignment.
 
(From Herzenberg JE, Hensinger RN, Dedrick DK, et al. Emergency transport and positioning of young children who have an injury of the cervical spine: the standard backboard may be hazardous. J Bone Joint Surg Am. 1989; 71:15–22, with permission.)
A: Young child on a modified backboard that has a cutout to the recess of the occiput, obtaining better supine cervical alignment. B: Young child on modified backboard that has a double-mattress pad to raise the chest, obtaining better supine cervical alignment.
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Figure 23-14
A: Young child on a modified backboard that has a cutout to the recess of the occiput, obtaining better supine cervical alignment. B: Young child on modified backboard that has a double-mattress pad to raise the chest, obtaining better supine cervical alignment.
(From Herzenberg JE, Hensinger RN, Dedrick DK, et al. Emergency transport and positioning of young children who have an injury of the cervical spine: the standard backboard may be hazardous. J Bone Joint Surg Am. 1989; 71:15–22, with permission.)
A: Young child on a modified backboard that has a cutout to the recess of the occiput, obtaining better supine cervical alignment. B: Young child on modified backboard that has a double-mattress pad to raise the chest, obtaining better supine cervical alignment.
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Cervical collars supplement backboards for immobilization in the trauma setting. While soft collars tend to be more comfortable and cause less soft tissue irritation, rigid collars are preferred for patients with acute injuries because they provide better immobilization. Even rigid collars may allow up to 17 degrees of flexion, 19 degrees of extension, 4 degrees of rotation, and 6 degrees of lateral motion.63,196 Supplemental sandbags and taping on either side of the head are recommended in all children and have been shown to limit the amount of spinal motion to 3 degrees in any plane.142 
Further displacement of an unstable cervical injury may occur if resuscitation is required. The placement of pediatric patients on an appropriate board with the neck in a neutral position makes recognition of some fractures difficult because positional reduction may have occurred, especially with ligamentous injuries or endplate fractures. An apparently normal lateral radiograph in a patient with altered mental status or multiple injuries does not rule out a cervical spine injury. A study of four patients with unstable cervical spine injuries who had attempted resuscitation in the emergency department showed that axial traction actually increased the deformity.31 Any manipulation of the cervical spine, even during intubation, must be done with caution and with the assumption that the patient has an unstable cervical spine injury until proven otherwise. 
The physical evaluation of any patient with a suspected cervical spine injury should begin with inspection. Head and neck trauma is associated with a high incidence of cervical spine injuries.4,16 Soft tissue abrasions or shoulder-harness marks on the neck from a seatbelt are clues to an underlying cervical spine injury (Fig. 23-15).95,106,140 Unconscious patients should be treated as if they have a cervical spine injury until further evaluation proves otherwise. The next step in the evaluation is palpation of the cervical spine for tenderness, muscle spasm, and overall alignment. The most prominent levels should be the spinous processes at C2, C3, and C7. Anterior palpation should focus on the presence of tenderness or swelling. The entire spine should be palpated and thoroughly examined because 20% of patients with cervical spine injuries have other spinal fractures. 
Note location of skin contusions from the seatbelt.
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Figure 23-15
Clinical photograph of a patient with a cervical spine injury resulting from impact with the shoulder harness of a seatbelt.
Note location of skin contusions from the seatbelt.
Note location of skin contusions from the seatbelt.
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A thorough neurologic examination should be done, which can be difficult in pediatric patients. Strength, sensation, reflexes, and proprioception should be documented. In patients who are uncooperative because of age or altered mental status, repeat examinations are important; however, the initial neurovascular examination should be documented even if it entails only gross movements of the extremities. The evaluation of rectal sphincter tone, bulbocavernosus reflex, and perianal sensation are important, especially in obtunded patients and patients with partial or complete neurologic injuries, regardless of age. Patients who are cooperative and awake can be asked to perform supervised flexion, extension, lateral rotation, and lateral tilt. Uncooperative or obtunded patients should not have any manipulation of the neck. 

Nonoperative Treatment of Cervical Spine Injury

Immobilization of the cervical spine may continue after the emergency setting if there is an injury that requires treatment. Specific injuries and their treatment are described later in this chapter. Further immobilization of some cervical spine injuries requires a cervical collar. A rigid collar can be used for immobilization if it is an appropriately fitting device with more padding than a standard cervical collar placed in the emergency department. More unstable or significant injuries can be treated with a custom orthosis, a Minerva cast, or a halo device. An advantage of custom devices is the ability to use lightweight thermoplastic materials that can be molded better to each patient's anatomy and can be extended to the thorax (Fig. 23-16). These devices must be properly applied for effective immobilization, and skin breakdown, especially over the chin region, needs to be carefully monitored. Minerva casts tend to provide more immobilization than thermoplastic devices, but their use is not as common and their application requires attention to detail. 
Figure 23-16
Custom-made cervicothoracic brace used to treat a C2 fracture that reduced in extension.
Flynn-ch023-image016.png
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A halo device can be used for the treatment of cervical spine injuries even in children as young as 1 year old.253 The halo can be used as either a ring alone to apply traction or with a vest for definitive immobilization of an unstable cervical spine injury. Prefabricated vests are available in sizes for infants, toddlers, and children, with measurements based on the circumference of the chest at the xiphoid process. 
The fabrication of a halo for any patient needs to consider both the size of the ring and the size of the vest. Prefabricated rings and prefabricated vests are available for even the smallest of patients and are based on circumferential measurements at the crown and at the xiphoid process. If the size of the patient or the anatomy of the patient does not fit within these standard sizes, the fabrication of a custom halo may be necessary. Mubarak et al.203 recommended the following steps in the fabrication of a custom halo for a child: (a) the size and configuration of the head are obtained with the use of the flexible lead wire placed around the head, (b) the halo ring is fabricated by constructing a ring 2 cm larger in diameter than the wire model, (c) a plaster mold of the trunk is obtained for the manufacture of a custom bivalved polypropylene vest, and (d) linear measurements are made to ensure appropriate length of the superstructure. 
The placement of pins into an immature skull deserves special attention because of the dangers of inadvertent skull penetration with a pin. CT imaging before halo application aids in determining bone structure and skull thickness. It also aids in determining whether or not cranial suture interdigitation is complete and if the fontanels are closed. The thickness of the skull varies greatly up to 6 years of age and is not similar to that of adults until the age of 16 years.175 Garfin et al.97 evaluated the pediatric cranium by CT and determined that the skull is thickest anterolaterally and posterolaterally, making these the optimal sites for pin placement. 
The number of pins used for placement of a ring and the insertion torques used in younger children also deserve special mention. The placement of pins at the torque pressures used in adults will lead to penetration during insertion.175 Pins should be inserted at torques of 2- to 4-in pounds; however, the variability and reliability of pressures found with various torque wrenches during cadaver testing are great, and each pin must be inserted cautiously.61 The use of 8 to 12 pins inserted at lower torque pressures aids in obtaining a stable ring with less chance of inadvertent penetration (Fig. 23-17). The insertion of each pin perpendicular to the skull also improves the pin–bone interface and the overall strength of the construct.62 We have had success using halo vests even in children younger than 2 years of age by using multiple pins inserted to finger-tightness rather than relying on torque wrenches. 
Figure 23-17
“Safe Zone” for halo pin insertion.
 
(Adapted from Manson NA, An HS. Halo placement in the pediatric and adult patient. In: Vaccaro AR, Barton EM: Operative Techniques in Spine Surgery. Philadelphia, PA: Saunders (2008), p. 13.185)
(Adapted from 


Manson NA,

An HS
. Halo placement in the pediatric and adult patient. In: 

Vaccaro AR,

Barton EM
: Operative Techniques in Spine Surgery. Philadelphia, PA: Saunders (2008), p. 13.185)
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Figure 23-17
“Safe Zone” for halo pin insertion.
(Adapted from Manson NA, An HS. Halo placement in the pediatric and adult patient. In: Vaccaro AR, Barton EM: Operative Techniques in Spine Surgery. Philadelphia, PA: Saunders (2008), p. 13.185)
(Adapted from 


Manson NA,

An HS
. Halo placement in the pediatric and adult patient. In: 

Vaccaro AR,

Barton EM
: Operative Techniques in Spine Surgery. Philadelphia, PA: Saunders (2008), p. 13.185)
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Technique of Halo Application
A halo can be applied in older children and adolescents with a local anesthetic; however, in most younger children a general anesthetic should be used. The patient is positioned on the operating table in a position that prevents unwanted flexion of the neck and maintains the proper relationship of the head and neck with the trunk. The area of skin in the region of pin insertion is cleaned with antiseptic solution and appropriate areas are shaved as needed for pin placement posteriorly. The ring is placed while an assistant holds the patient's head; it should be placed just below the greatest circumference of the skull, which corresponds to just above the eyebrows anteriorly and 1 cm above the tips of the earlobes laterally. We recommend injection of local anesthetic into the skin and periosteum through the ring holes in which the pins will be placed. The pins are placed with sterile technique. 
To optimize pin placement, a few points should be kept in mind. The thickest area of the skull is anterolaterally and posterolaterally, and pins inserted at right angles to the bone have greater force distribution and strength.62,97 Anterior pins should be placed to avoid the anterior position of the supraorbital and supratrochlear nerves (Fig. 23-18). Placement of the anterior pins too far laterally will lead to penetration of the temporalis muscle, which can lead to pain with mastication and talking, as well as early pin loosening. The optimal position for the anterior pins is in the anterolateral skull, just above the lateral two-thirds of the orbit and just below the greatest circumference of the skull. The posterior pins are best placed posterolaterally directly diagonal from the anterior pins. We also recommend placing the pins to finger-tightness originally and tightening two directly opposing pins simultaneously. During placement of the pins, meticulous attention should be paid to the position of the ring to have a circumferential fit on the patient's skull and to avoid any pressure of the ring on the scalp, especially posteriorly. 
Figure 23-18
Child immobilized in a halo for C1 to C2 rotary subluxation.
 
Note the position of the anterior pins, as well as the placement of the posterior pins at 180 degrees opposite the anterior pins.
Note the position of the anterior pins, as well as the placement of the posterior pins at 180 degrees opposite the anterior pins.
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Figure 23-18
Child immobilized in a halo for C1 to C2 rotary subluxation.
Note the position of the anterior pins, as well as the placement of the posterior pins at 180 degrees opposite the anterior pins.
Note the position of the anterior pins, as well as the placement of the posterior pins at 180 degrees opposite the anterior pins.
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The number of pins used and the torque pressures applied vary according to the age of the patient. In infants and younger children, we recommend the placement of multiple pins (8 to 12) tightened to finger-tightness or 2- to 4-in pounds to avoid unwanted skull penetration. In older children, six to eight pins are used and tightened to 4-in pounds. In adolescents, four to eight pins can be tightened with a standard torque wrench to 6- to 8-in pounds. Once the pins are tightened, they must be fastened to the ring by the appropriate lock nuts or set screws. The halo vest and superstructure are then applied, with care to maintain the position of the head and neck. Appropriate positioning of the head and neck can be done by adjusting the superstructure (Fig. 23-19). 
Figure 23-19
 
(Left)Custom halo vest and superstructure. (Right)In the multiple-pin, low-torque technique, 10 pins are used for an infant halo ring attachment. Usually, four pins are placed anteriorly, avoiding the temporal region, and the remaining six pins are placed in the occipital area.
 
(From Mubarak SJ, Camp JF, Fuletich W, et al. Halo application in the infant. J Pediatr Orthop. 1989; 9:612–613, with permission.)
(Left)Custom halo vest and superstructure. (Right)In the multiple-pin, low-torque technique, 10 pins are used for an infant halo ring attachment. Usually, four pins are placed anteriorly, avoiding the temporal region, and the remaining six pins are placed in the occipital area.
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Figure 23-19
(Left)Custom halo vest and superstructure. (Right)In the multiple-pin, low-torque technique, 10 pins are used for an infant halo ring attachment. Usually, four pins are placed anteriorly, avoiding the temporal region, and the remaining six pins are placed in the occipital area.
(From Mubarak SJ, Camp JF, Fuletich W, et al. Halo application in the infant. J Pediatr Orthop. 1989; 9:612–613, with permission.)
(Left)Custom halo vest and superstructure. (Right)In the multiple-pin, low-torque technique, 10 pins are used for an infant halo ring attachment. Usually, four pins are placed anteriorly, avoiding the temporal region, and the remaining six pins are placed in the occipital area.
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Daily pin care should consist of hydrogen peroxide/saline cleaning at the pin–skin interface. Retightening of pins at 48 hours should be avoided in infants and children to prevent skull penetration; however, in adolescents, the pins can be retightened at 48 hours with a standard torque wrench. Local erythema or drainage may occur about the pins and can be managed with oral antibiotics and continued pin site care. If significant loosening occurs or the infection is more serious, the pin or pins should be removed. Occasionally, a dural puncture occurs during pin insertion or during the course of treatment. This necessitates pin removal and prophylactic antibiotics until the tear heals, usually at 4 to 5 days. 
Outcomes
The complication rate related to the use of a halo in one series of patients was 68%; however, all patients were able to wear the halo until fracture healing occurred or arthrodesis was achieved.56 The most common complications in this series were superficial pin track infection and pin loosening. Other complications that occur less frequently include dural penetration, supraorbital nerve injury, unsightly pin scars, and deep infection.23,71 Prefabricated halo vests are used in adults and are easily fitted to older adolescents. Because of the age and size ranges of children, however, a custom vest or even a cast vest may be needed. Improper fitting of a vest may allow unwanted movement of the neck despite the halo, and any size mismatch requires a custom vest or cast vest (see Fig. 23-19). 

Nonoperative Treatment of Spinal Cord Injury

If an acute spinal cord injury is determined by examination, the administration of methylprednisolone within the first 8 hours after injury has been shown to improve the chances of neurologic recovery.3336 Methylprednisolone in the treatment of acute spinal cord injuries has been shown to improve motor and sensory recovery when evaluated 6 weeks and 6 months after injury35; however, this positive effect on neurologic recovery is limited to those treated within the first 8 hours of injury. The initial loading dose of methylprednisolone is 30 mg/kg body weight. If the loading dose is given within 3 hours after injury, then a maintenance infusion of 5.4 mg/kg is given for 24 hours after injury. If the loading dose is given between 3 and 8 hours after injury, then a maintenance infusion of 5.4 mg/kg is given for 48 hours after injury. Methylprednisolone decreases edema, has an anti-inflammatory effect, and protects the cell membranes from scavenging oxygen-free radicals.3336 
Once spinal cord injury is diagnosed, routine care includes prophylaxis for stress ulcers, routine skin care to prevent pressure sores, and initial Foley catheterization followed by intermittent catheterization and a bowel training program. 
Outcomes
In several series,3336 there was a slight increase in the incidence of wound infections but no significant increase in gastrointestinal bleeding. All of these studies involved patients 13 years or older, so no documentation of the efficacy in young children exists. A combination of methylprednisolone and GM1-ganglioside (GM1) is being studied for its possible beneficial effect on an injured spinal cord.99102 GM1 is a complex acid-like lipid found at high levels in the cell membrane of the central nervous system that is thought to have a neuroprotective and neurofunctional restorative potential. Early studies have shown that patients given both drugs had improved recovery over those who had received just methylprednisolone. Spinal cord injury remains the most devastating complication after cervical spine fractures. The outcome after a spinal cord injury has been shown to be better in children than in adults and varying and unpredictable improvement in function may occur.225 The role of steroids in minimizing the inflammatory cascade and limiting neuronal injury has been well received after the results of the National Acute Spinal Cord Injury Studies (NASCIS) were published.3336 Recently, the results of the studies have been called into question, and the evidence remains confusing to the physician taking care of patients with spinal cord injuries. There currently are no randomized clinical trials that have been performed in children with regard to pharmacologic measures to be taken after a spinal cord injury.226 With that being said, many clinicians continue administer steroids to children in the acute setting of a spinal cord injury given the potentially devastating effects of such an injury. The original recommendations to be followed were: methylprednisolone sodium succinate in a dose regimen of bolus 30 mg/kg over 15 minutes, with maintenance infusion of 5.4 mg/kg per hour infused for 23 hours. No clear evidence exists for the administration of steroids after spinal cord injury; however, a recent review on the subject reveals that many physicians continue to practice this in the face of an injury because of the perceived risks of litigation.113 The potential side effects of steroids, namely pulmonary complications and wound complications, should be weighed against both the paucity of evidence regarding their therapeutic value and the institutional protocols that may be in place for spinal cord injury patients. 
With incomplete lesions, children have a better chance than adults for useful recovery. Hadley et al.115 noted that 89% of pediatric patients with incomplete spinal cord lesions improved, whereas only 20% of patients with complete injuries had evidence of significant recovery. Laminectomy has not been shown to be beneficial and can actually be harmful270,320 because it increases instability in the cervical spine; for example, it can cause a swan neck deformity or progressive kyphotic deformity.188,274 The risk of spinal deformity after spinal cord injury has been investigated by several researchers.21,25,47,85,158,188 Mayfield et al.188 found that patients who had a spinal cord injury before their growth spurt all developed spinal deformities, 80% of which were progressive. Ninety-three percent developed scoliosis, 57% kyphosis, and 18% lordosis. Sixty-one percent of these patients required spinal arthrodesis for stabilization of their curves. Orthotic management usually is unsuccessful, but in some patients it delays the age at which arthrodesis is necessary. Lower extremity deformities also may occur, such as subluxations and dislocations about the hip. Pelvic obliquity can be a significant problem and may result in pressure sores and difficulty in seating in a wheelchair. 

Nonoperative Treatment of Neonatal Injury

Treatment of neonatal cervical spine injuries is nonoperative and should consist of careful realignment and positioning of the child on a bed with neck support or a custom cervical thoracic orthosis. Healing of bony injuries usually is rapid and complete.281 

Operative Treatment of Cervical Spine Injury

Indications and contraindications are discussed with specific techniques later in the chapter. 
Surgical Procedure(s)
Specific procedures are discussed later the chapter. 
Preoperative Planning
The patient with an unstable cervical spine injury must be intubated and properly positioned to avoid further injury. 
Stabilization
The injured cervical spine should be immobilized during transport. As discussed early in this chapter, in patients younger than 8 years of age the use of a backboard with and occipital recess or having the trunk elevated approximately 2.5 cm is recommended. This will allow the cervical spine to remain in neutral alignment due to the relative large head size compared with the trunk size in these younger patients. Soft cervical collars provide no significant stability to the cervical spine. Properly fitting cervical collars offer better support. The addition of sandbags and tape immobilization offers even more support. 
Airway Management
In a patient with an unstable cervical spine, manipulation during intubation may injure the spinal cord. Axial traction, in particular, has been shown to result in increased distraction during intubation compared with either no immobilization or manual stabilization and is not recommended.172 Manual in-line stabilization (MILS) is the most widely accepted technique for immobilization during intubation. This technique consists of grasping the mastoid processes with the fingertips with no traction being applied and then cupping the occiput in the palm of the hands.104,183 Studies have confirmed the clinical safety of orotracheal intubation by direct laryngoscopy with MILS in patients with cervical spine injury.256,267 
Several methods for intubation have been described for the patient with an unstable cervical spine. Awake intubation that is sometimes performed in adult patients is not feasible in the pediatric patient. Direct laryngoscopy with MILS is the method most often used. Fiberoptic intubation with MILS is a popular alternative. This causes minimal cervical movement and facilitates improved visualization of the vocal cords during intubation. However the time to intubation with the fiberoptic technique is twice as long compared with direct laryngoscopy. The GlideScope videolaryngoscopy (Verathon, Bothell, WA) provides an indirect view of the glottis on a screen and has the potential for reduced motion. Nasotracheal intubation can be performed fiberoptically or without direct visualization. This technique is contraindicated in patient with basilar skull fractures or craniofacial trauma, which often is the case in pediatric cervical spine trauma. 
Spinal Cord Monitoring
Spinal cord monitoring is usually used during surgical stabilization of the unstable cervical spine. Motor potential and SSEP are used for monitoring (Table 23-2). 
 
Table 23-2
Cervical Spine Injury
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Table 23-2
Cervical Spine Injury
Preoperative Planning Checklist
  •  
    Appropriate stabilization and immobilization
  •  
    Airway management and intubation
  •  
    Spinal cord monitoring
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Positioning
The two primary techniques for prone positioning of patients with cervical spine injuries are manual turning using the log-roll technique or use of a spinal positioning table. Cadaver models have shown that turning using a spinal positioning table and a cervical collar results in the least amount of motion and is the preferred technique. If a spinal positioning table is not available, however, the log-roll technique with a cervical collar can be used. Once the patient is positioned, Gardner-Wells tongs or a halo are applied and attached to a Mayfield headrest attachment. Care must be taken when using these devices, because the head is in a fixed position and the torso is relatively free. Distraction and translation at the fracture site can occur, and fluoroscopy is recommended to verify proper alignment of the cervical spine when the patient is prone. 
Surgical Approaches
The two most common approaches for surgical treatment of the unstable pediatric cervical spine are the posterior approach and anterior approach.265 The posterior approach is the most commonly used and is most familiar to most orthopedic surgeon.289 
Posterior Approach
This approach has been well described and can extend from the base of the occiput to the upper thoracic spine. 
Technique
An incision is made in the midline from the suboccipital area down to C3 and can extend distally to C7 or T1 The dissection is extended deep within the relatively avascular intermuscular septum (also known as the ligamentum nuchae) and the cervical musculature is released from the spinous process of C2 and C3. The inferior suboccipital region, the entire posterior arch of C1, and the posterior elements of the C2 to C3 are exposed in a subperiosteal fashion. Bipolar cautery should be used judiciously and hemostatic products incorporated as needed to control bleeding from the perivertebral artery venous plexus, particularly at the C1 to C2 interlaminar space. Dissection at C1 should not go more than 1.5 cm lateral to the midline due to the vertebral artery being 2 cm from the midline in adults and sometimes closer in small children (Table 23-3). 
 
Table 23-3
Posterior Approach to Cervical Spine
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Table 23-3
Posterior Approach to Cervical Spine
Surgical Steps
  •  
    Incision: Midline from suboccipital area to C3
  •  
    Dissect deep to ligamentum nuchae
  •  
    Release cervical musculature
  •  
    Expose inferior suboccipital region, posterior arch of C1 and posterior elements of C2–C3 congenital fusion mass
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Postoperative Care
Postoperative care depends on the type of procedure performed (see specific techniques later in the chapter). 
Potential Pitfalls and Preventative Measures
  1.  
    Autofusion of all exposed vertebrae
  2.  
    Vertebral artery injury with lateral dissection at C1
  3.  
    Lordosis in posterior-only fusion
Anterior Approach
The anterior exposure is performed with the patient supine through a lateral retropharyngeal approach. The lateral retropharyngeal approach described by Whitesides and Kelly is an extension of the Henry approach to the vertebral artery. The sternocleidomastoid muscle is everted and retracted posteriorly, and the remainder of the dissection follows a plane posterior to the carotid sheath. 
Technique
A longitudinal incision is made along the anterior margin of the sternocleidomastoid muscle. At the superior end of the muscle, the incision is carried posteriorly across the base of the temporal bone. The muscle is divided at its mastoid origin. The splenius capitis muscle is partially divided at its insertion in the same area. At the superior pole of the incision is the external jugular vein, which crosses the anterior margin of the sternocleidomastoid; this vein should be divided and ligated. Branches of the auricular nerve also may be encountered and may require division. The sternocleidomastoid muscle is everted and the spinal accessory nerve is identified as it approaches and passes into the muscle. The vascular structures that accompany the nerve are divided and ligated. The approach posterior to the carotid sheath and anterior to the sternocleidomastoid muscle is developed (Fig. 23-20). The transverse processes of all the exposed cervical vertebrae are palpable in this interval. Using sharp and blunt dissection, the plane between the alar and prevertebral fascia are developed along the anterior aspect of the transverse processes of the vertebral bodies. The dissection plane is anterior to the longus colli and capitis muscles and the overlying sympathetic trunk and superior cervical ganglion. (An alternative approach is to elevate the longus colli and capitis muscles from their bony insertion on the transverse processes, and retract the muscles anteriorly; however, this approach may disrupt the sympathetic rami communicantes and cause Horner syndrome.) When the vertebral level is identified, a longitudinal incision to bone is made through the anterior longitudinal ligament. The ligament and soft tissues are dissected subperiosteally to expose the vertebral bodies. Instrumentation and fusion may be performed as needed. The wound is irrigated and closed in layers over a suction drain in the retropharyngeal space (Table 23-4). 
Figure 23-20
Anterior approach to the cervical spine
 
(From Canale ST, Beaty JH, Campbell's operative orthopaedics. 12th ed. Philadelphia, PA: Elsevier/Mosby; 2013.)
(From 


Canale ST, and

Beaty JH
, Campbell's operative orthopaedics. 12th ed. Philadelphia, PA: Elsevier/Mosby; 2013.)
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Figure 23-20
Anterior approach to the cervical spine
(From Canale ST, Beaty JH, Campbell's operative orthopaedics. 12th ed. Philadelphia, PA: Elsevier/Mosby; 2013.)
(From 


Canale ST, and

Beaty JH
, Campbell's operative orthopaedics. 12th ed. Philadelphia, PA: Elsevier/Mosby; 2013.)
View Original | Slide (.ppt)
X
 
Table 23-4
Anterior Approach to Cervical Spine
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Table 23-4
Anterior Approach to Cervical Spine
Surgical Steps
  •  
    Incise along anterior margin of sternocleidomastoid muscle and carry posteriorly across base of temporal bone
  •  
    Divide muscles and nerve and ligate external jugular vein
  •  
    Identify spinal accessory nerve and divide and ligate the vascular structures accompanying the nerve
  •  
    Develop plane between alar and prevertebral fascia anterior to longus colli and capitis muscles
  •  
    Identify vertebral level and make incision through anterior longitudinal ligament
  •  
    For fusion place corticocancellous strips in trough made in vertebral bodies
  •  
    Irrigate and close wound in layers
X
Postoperative Care
The patient should be monitored closely for postoperative edema and airway obstruction. The patient is immobilized in a cervicothoracic brace or halo vest or halo cast. 
Anterior Approach
deAndrade and Macnab described an approach to the upper cervical spine that is an extension of the approach described by Robinson and Southwick and Bailey and Badgley. This approach is anterior to the sternocleidomastoid muscle, but the dissection is anterior to the carotid sheath rather than posterior. This approach carries an increased risk of injury to the superior laryngeal nerve. 
Potential Pitfalls and Preventive Measures
  1.  
    Recurrent laryngeal nerve
  2.  
    Implant size
  3.  
    Progressive kyphosis

Occiput-C1 Injuries

Introduction to Occipital Condylar Fracture

Occipital condylar fractures are rare, and their diagnosis requires a high index of suspicion.198,209 
This fracture was described by Bell in 1817 after a postmortem examination of a patient who fell backward off a wall, and upon being discharged from the hospital turned his head to bid farewell and died immediately because of the instability of his neck injury. The use of CT scan as a diagnostic tool in patients with cranial cervical trauma has led to increased recognition of this injury. The reported incidence of occipital condylar fractures in pediatric patients is not known, as most reported cases are in adult patients.151 Hanson et al.121 estimated an incidence of 1 to 20 per 1000 patients. Nobel and Smoker reported an incidence of 1% after CT examination of head and neck in trauma patients.209 

Assessment of Occipital Condylar Fracture

Mechanisms of Injury for Occipital Condylar Fracture

Fracture may be caused by axial loading with a component of ipsilateral flexion, by an extension of a basilar skull fracture, or by extreme rotation or lateral bending causing avulsion fracture of the inferomedial portion of the condyle that is attached to the alar ligament. 

Associated Injuries with and Signs and Symptoms of Occipital Condylar Fracture

Most patients with occipital condylar fractures have associated head injuries.198 Reports of associated cranial nerve deficits vary from 31% to 53% of patients with occipital condylar fractures.10,121,296 Damage to the hypoglossal nerve can occur as the nerve passes through the hypoglossal canal that is located above the middle third of the occipital condyle. The function of the hypoglossal nerve can be assessed by asking the patient to protrude the tongue. It will deviate to the paralyzed side.56 When cranial nerve deficits are noted, the presentation is acute in two-thirds of patient and delayed in one-third of the patients. Delayed cranial nerve palsies may be the result of migration of the fractured bony fragments or compression from proliferation of bone and fibrous tissue during the healing process. Vascular injuries involving the posteroinferior cerebellar artery and carotid arteries also have been reported with occipital condylar fracture.54,149,152,164,173,177 
The clinical presentation is variable. Pain and tenderness in the posterior occipitocervical region or torticollis may be the only complaints, whereas others may have significant neurologic deficits. 

Imaging and Other Diagnostic Studies for Occipital Condylar Fracture

Plain radiographs often do not clearly show occipital condylar fractures, and CT with multiplanar reconstruction usually is necessary to establish the diagnosis.17,51 
The presence of a retropharyngeal hematoma on a lateral radiograph of the cervical spine may be the only clue to a fracture of the occipital condyle. Tuli et al.296 recommended that a CT scan be obtained in the following circumstances: presence of lower cranial nerve deficits, associated head injury or basal skull fracture, or persistent neck pain despite normal radiographs. 

Classification of Occipital Condylar Fracture

Anderson and Montesano10 described three types of occipital condylar fractures (Table 23-5 and Fig. 23-21): type I, impaction fracture; type II, basilar skull fracture extending into the condyle; and type III, avulsion fractures. An avulsion fracture is the only type of occipital condylar fracture that is unstable. Type I injuries are the result of axial compression with a component of ipsilateral flexion. Type II injuries are basilar skull fractures that extend to involve the occipital condyle and usually are caused by a direct blow. Type III injuries are avulsion fractures of the inferomedial portion of the condyle that is attached to the alar ligament. Types I and II occipital condylar fractures usually are stable. Type III or avulsion fractures can be stable or unstable.6 
Table 23-5
Anderson and Montesano Classification of Occipital Condylar Fractures
Type Description Biomechanics
I Impaction Results from axial loading; ipsilateral alar ligament may be compromised, but stability is maintained by contralateral alar ligament and tectorial membrane.
II Skull base extension Extends from occipital bone via condyle to enter foramen magnum; stability is maintained by intact alar ligaments and tectorial membrane.
III Avulsion Mediated via alar ligament tension; associated disruption of tectorial membrane and contralateral alar ligament may cause instability.
 

From Hanson JA et al.121 compiled from Anderson PA and Montesano PX. Morphology and treatment of occipital condyle fractures. Spine. 1988; 13:731–736.

X
Figure 23-21
Classification of occipital condylar fractures according to Anderson and Monsanto.9
 
A: Type I fractures can occur with axial loading. B: Type II fractures are extensions of basilar cranial fractures. C: Type III fractures can result from an avulsion of the condyle during rotation, lateral bending, or a combination of mechanisms.
 
(From Hadley MN. Occipital condyle fractures. Neurosurgery. 2002; 50(Suppl):S114–S119, with permission.)114
A: Type I fractures can occur with axial loading. B: Type II fractures are extensions of basilar cranial fractures. C: Type III fractures can result from an avulsion of the condyle during rotation, lateral bending, or a combination of mechanisms.
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Figure 23-21
Classification of occipital condylar fractures according to Anderson and Monsanto.9
A: Type I fractures can occur with axial loading. B: Type II fractures are extensions of basilar cranial fractures. C: Type III fractures can result from an avulsion of the condyle during rotation, lateral bending, or a combination of mechanisms.
(From Hadley MN. Occipital condyle fractures. Neurosurgery. 2002; 50(Suppl):S114–S119, with permission.)114
A: Type I fractures can occur with axial loading. B: Type II fractures are extensions of basilar cranial fractures. C: Type III fractures can result from an avulsion of the condyle during rotation, lateral bending, or a combination of mechanisms.
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Tuli et al.296 also classified occipital condylar fractures based on displacement and stability of the occiput/C1 to C2 complex (Table 23-6). In their classification, type 1 fractures are nondisplaced and type 2 are displaced. They further subdivided type 2 fractures into type 2A, displaced but stable, and type 2B, displaced and unstable. 
 
Table 23-6
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Table 23-6
Classification of Occipital Condylar Fractures226
Type Description Biomechanics
1 Nondisplaced Stable
2A Displaceda Stable; no radiographic, CT, or MRI evidence of occipitoatlantoaxial instability of ligamentous disruption
2B Displaceda Unstable; positive radiographic, CT, or MRI evidence of occipitoatlantoaxial instability or ligamentous disruption
 

Information from Hanson JA et al.121 compiled from: Tuli S, Tator CH, Fehlings MG, Mackay, M. Occipital condyle fractures. Neurosurgery. 1997; 41:368–377.

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Treatment Options for Occipital Condylar Fracture

Nonoperative Treatment of Occipital Condylar Fracture

Most occipital condylar fractures are stable and can be treated with a cervical orthosis or halo immobilization. Anderson and Montesano Type I and II are stable fractures and can be treated with a cervical orthosis. Tuli type 1 and type 2A are stable and can be treated with a cervical orthosis (Table 23-7). 
 
Table 23-7
Occipital Condylar Fracture
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Table 23-7
Occipital Condylar Fracture
Nonoperative Treatment
Indications Relative Contraindications
Stable Anderson and Montesano type I and II occipital condylar fracture Anderson and Montesano Type III fracture
Tuli type 1 and type 2A Tuli type 2B fracture
Cranial cervical instability
X

Operative Treatment of Occipital Condylar Fracture

The decision for surgery is based on cranial cervical instability. Bilateral occipital condylar fractures usually are unstable and require occipital cervical fusion.121 Type III may be unstable and require occipital cervical fusion. Type 2B will need an occipital cervical fusion. 
Surgical Procedure
See pp. 865–868 for occipital cervical fusion techniques. 

Atlantooccipital Instability

Atlantooccipital dislocation was once thought to be a rare fatal injury found only at the time of autopsy (Fig. 23-22).16,30,33,43,273 This injury is now being recognized more often, and children are surviving.71,78,82,223,280 Bulas et al.44 reported 11 atlantooccipital dislocations in 1,600 pediatric trauma patients (a 0.7% prevalence) seen over a 5-year period; six children died with severe neurologic deficits, but five patients survived with minimal or no neurologic sequela. This increase in the survival rate may be due to increased awareness and improved emergency care with resuscitation and spinal immobilization by emergency personnel. 
Figure 23-22
Patient with atlantooccipital dislocation.
 
Note the forward displacement of the Wackenheim line and the significant anterior soft tissue swelling.
Note the forward displacement of the Wackenheim line and the significant anterior soft tissue swelling.
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Figure 23-22
Patient with atlantooccipital dislocation.
Note the forward displacement of the Wackenheim line and the significant anterior soft tissue swelling.
Note the forward displacement of the Wackenheim line and the significant anterior soft tissue swelling.
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Assessment of Atlantooccipital Instability

Mechanisms of Injury for Atlantooccipital Instability

Atlantooccipital dislocation occurs in sudden acceleration and deceleration accidents, such as motor vehicle or pedestrian–vehicle accidents. The head is thrown forward, and this can cause sudden craniovertebral separation. 
The atlantooccipital joint is a condylar joint that has little inherent bony stability. Stability is provided by the ligaments about the joint. The primary stabilizers are the paired alar ligaments, the articular capsule, and the tectorial membrane (a continuation of the posterior longitudinal ligament and the major stabilizer of the atlantooccipital joint). In children, this articulation is not as well formed as in adults and it is less cup-shaped. Therefore, there is less resistance to translational forces.16,27,30,43,44,273 Sectioning of the tectorial membrane in biomechanical cadaver studies have resulted in instability from the occiput to C2.126,149 

Associated Injuries with and Signs and Symptoms of Atlantooccipital Instability

Diagnosis may be difficult because atlantooccipital dislocation is a ligamentous injury. Spontaneous reduction after initial immobilization may occur and up to 60% may be missed on initial examination.149,283,286 Although patients with this injury have a history of trauma, some may have no neurologic findings. Others, however, may have symptoms such as cranial nerve injury, vomiting, headache, torticollis, or motor or sensory deficits.43,49,58,123,138,223 Brain stem symptoms, such as ataxia and vertigo, may be caused by vertebrobasilar vascular insufficiency. Closed head injury and facial trauma are frequently associated with atlantooccipital instability. The high association of closed head injures that may mask other physical findings. Unexplained weakness or difficulty in weaning off a ventilator after a closed head injury may be a sign of this injury. 

Imaging and Other Diagnostic Studies for Atlantooccipital Instability

The treating physician must have a high index of suspicion in children with closed head injuries or associated facial trauma and must be aware of the radiographic findings associated with atlantooccipital dislocation. A significant amount of anterior soft tissue swelling usually can be seen on a lateral cervical spine radiograph. This increased anterior soft tissue swelling should be a warning sign that an atlantooccipital dislocation may have occurred. 
Radiographic findings that aid in the diagnosis of atlantooccipital dislocation are the Wackenheim line, Powers ratio, dens–basion interval, and occipital condylar distance. The Wackenheim line is drawn along the clivus and should intersect tangentially the tip of the odontoid. A shift anterior or posterior of this line represents either an anterior or posterior displacement of the occiput on the atlas (Fig. 23-23). This line is probably the most helpful because it is reproducible and easy to identify on a lateral radiograph. The Powers ratio (see Fig. 23-1) is determined by drawing a line from the basion to the posterior arch of the atlas (BC) and a second line from the opisthion to the anterior arch of the atlas (OA). The length of line BC is divided by the length of the line OA, producing the Powers ratio. A ratio of more than 1.0 is diagnostic of anterior atlantooccipital dislocation. A ratio of less than 0.7 is diagnostic of posterior atlantooccipital dislocation. Values between 1.0 and 0.7 are considered normal.156 The Powers ratio has the advantage of not being affected by magnification of the radiograph, but the landmarks may be difficult to define. Another radiographic measurement is the dens–basion interval. The distance is measured between the apex of the dens and the tip of the clivus (basion). If the interval measures more than 1.2 cm, then disruption of the atlantooccipital joint has occurred.44,235 Kaufman et al.153 described an occipital condylar facet distance of more than 5 mm from the occipital condyle to the C1 facet as indicative of atlantooccipital injury. They recommended measuring this distance from five reference points along the occipital condyle and the C1 facet (Fig. 23-24). Harris et al.125,126 described the basion–axial interval. A posterior axial line (PAL) is drawn tangential to the posterior wall of the C2 vertebra. A line parallel to the PAL is drawn through the basion. Normal values for children are from 0 to 12 mm. Sun et al.286 proposed using an interspinous ratio that was sensitive and specific in detecting tectorial membrane injuries. The interspinous distance between C1 and C2 and between C2 and C3 are determined on lateral radiographs or CT scans. The ratio C1 to C2:C2 to C3 of more than 2.5 was indicative of injury to the tectorial membrane.149,218,286 
Figure 23-23
Craniovertebral dislocation.
 
A: Lateral view shows extensive soft tissue swelling. The distance between the basion and the dens is 2.4 cm (arrows) (normal is 1 cm). B: Line drawing shows the abnormal relationship between the occiput and the upper cervical spine.
 
(From El-Khoury GY, Kathol MH. Radiographic evaluation of cervical trauma. Semin Spine Surg. 1991; 3:3–23, with permission.)80
A: Lateral view shows extensive soft tissue swelling. The distance between the basion and the dens is 2.4 cm (arrows) (normal is 1 cm). B: Line drawing shows the abnormal relationship between the occiput and the upper cervical spine.
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Figure 23-23
Craniovertebral dislocation.
A: Lateral view shows extensive soft tissue swelling. The distance between the basion and the dens is 2.4 cm (arrows) (normal is 1 cm). B: Line drawing shows the abnormal relationship between the occiput and the upper cervical spine.
(From El-Khoury GY, Kathol MH. Radiographic evaluation of cervical trauma. Semin Spine Surg. 1991; 3:3–23, with permission.)80
A: Lateral view shows extensive soft tissue swelling. The distance between the basion and the dens is 2.4 cm (arrows) (normal is 1 cm). B: Line drawing shows the abnormal relationship between the occiput and the upper cervical spine.
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Figure 23-24
 
Atlantooccipital joint measurement points 1 through 5 demonstrated on a normal cross-table lateral skull radiograph in an 8-year-old (A) and a 14-year-old (B).
 
(From Kaufman RA, Carroll CD, Buncher CR. Atlantooccipital junction: standards for measurement in normal children. AJNR Am J Neuroradiol. 1987; 8:995–999, with permission.)
Atlantooccipital joint measurement points 1 through 5 demonstrated on a normal cross-table lateral skull radiograph in an 8-year-old (A) and a 14-year-old (B).
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Figure 23-24
Atlantooccipital joint measurement points 1 through 5 demonstrated on a normal cross-table lateral skull radiograph in an 8-year-old (A) and a 14-year-old (B).
(From Kaufman RA, Carroll CD, Buncher CR. Atlantooccipital junction: standards for measurement in normal children. AJNR Am J Neuroradiol. 1987; 8:995–999, with permission.)
Atlantooccipital joint measurement points 1 through 5 demonstrated on a normal cross-table lateral skull radiograph in an 8-year-old (A) and a 14-year-old (B).
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MRI is useful in diagnosing atlantooccipital dislocation by showing soft tissue edema around the tectorial membranes and lateral masses and ligament injury or disruption.45 Steinmetz et al.283 and Sun et al.286 suggested that the disruption of the tectorial membrane is the critical threshold for instability of the occipitoatlantal joint. Disruption of the tectorial membrane can best be identified by MRI. 

Classification of Atlantooccipital Instability

Atlantooccipital dislocation is classified radiographically into three types: longitudinal distraction with axial occipital separation, rotational injury, and anterior or posterior occipital displacement with respect to the atlas.294 

Treatment Options for Atlantooccipital Instability

Nonoperative Treatment of Atlantooccipital Instability

Because atlantooccipital dislocation is a ligamentous injury, nonoperative treatment usually is unsuccessful. Although Farley et al.84 reported successful stabilization in a halo, Georgopoulos et al.103 found persistent atlantooccipital instability after halo immobilization. Immobilization in a halo should be used with caution: if the vest or cast portion is not fitted properly, displacement can increase (Fig. 23-25) because the head is fixed in the halo but movement occurs because of inadequate immobilization of the trunk in the brace or cast. Traction should be avoided because it can cause distraction of the skull from the atlas (Table 23-8). 
Figure 23-25
 
A: Lateral radiograph of a patient with atlantooccipital dislocation. Note the increase in the facet condylar distance. B: Lateral radiograph after occipital C1 arthrodesis.
A: Lateral radiograph of a patient with atlantooccipital dislocation. Note the increase in the facet condylar distance. B: Lateral radiograph after occipital C1 arthrodesis.
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Figure 23-25
A: Lateral radiograph of a patient with atlantooccipital dislocation. Note the increase in the facet condylar distance. B: Lateral radiograph after occipital C1 arthrodesis.
A: Lateral radiograph of a patient with atlantooccipital dislocation. Note the increase in the facet condylar distance. B: Lateral radiograph after occipital C1 arthrodesis.
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Table 23-8
Atlantooccipital Instability
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Table 23-8
Atlantooccipital Instability
Nonoperative Treatment
Indications Relative Contraindications
Nonoperative treatment is usually unsuccessful
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Operative Treatment of Atlantooccipital Instability

Surgical stabilization is the recommended treatment.137 Posterior arthrodesis can be performed in situ, with wire fixation or fixation with a contoured Luque rod and wires or contoured rod and screw fixation.13,86,109,122,128,130,193,247,249 If the C1 to C2 articulation is stable, arthrodesis may be only from the occiput to C1 so that C1 to C2 motion is preserved.279,316 Stability of the C1 to C2 articulation often is questionable, and arthrodesis may need to be extended to C2.150 Most researchers also have expressed reservations about the chance of obtaining fusion in the narrow atlantooccipital interval and have recommended arthrodesis from the occiput to C2.15,149 
For a patient who presents very late with an unreduced dislocation, an in situ arthrodesis is recommended. DiBenedetto and Lee67 recommended arthrodesis in situ with a suboccipital craniectomy to relieve posterior impingement. 
Instability at the atlantooccipital joint is increased in patients with Down syndrome as well as in those with a high cervical arthrodesis below the axis. These patients may be at risk of developing chronic instability patterns and are at higher risk of having instability after trauma. 
Several methods of obtaining an occiput to C2 arthrodesis are available to the treating surgeon. The decision of which technique is used usually is based on stability and anatomy of the upper cervical spine of the patient. Because of the inherent instability associated with traumatic injuries to the upper cervical spine, internal fixation is preferred. Instrumentation with rods and screws may not always be possible because of the patient's size and anatomy. When instrumentation cannot be used, the surgeon must be aware of fusion and other stabilization techniques that may rely on stability obtained from the bone graft or wires and cables. These techniques will usually need to be supplemented with external immobilization such as a halo vest or cast or a Minerva cast. Acute hydrocephalus can occur after this injury or in the early postoperative period because of changes in cerebrospinal fluid flow at the cranial-cervical junction. 

Surgical Procedures for Occiput-C1 Injuires

Surgical Procedure: Occiput to C2 Arthrodesis without Internal Fixation

In younger children in whom the posterior elements are absent at C1 or separation is extensive in the bifid part of C1 posteriorly, posterior cervical arthrodesis from the occiput to C2 with iliac crest bone graft may be performed using a periosteal flap from the occiput to provide an osteogenic tissue layer for the bone graft (Fig. 23-26).163 
Figure 23-26
Technique of occipitocervical arthrodesis used when the posterior arch of C1 is absent.
 
A: Exposure of the occiput, atlas, and axis. B: Reflection of periosteal flap to cover defect in atlas. C: Decortication of exposed vertebral elements. D: Placement of autogenous cancellous iliac bone grafts.
 
(From Koop SE, Winter RB, Lonstein JE. The surgical treatment of instability of the upper part of the cervical spine in children and adolescents. J Bone Joint Surg Am. 1984; 66:403, with permission.)
A: Exposure of the occiput, atlas, and axis. B: Reflection of periosteal flap to cover defect in atlas. C: Decortication of exposed vertebral elements. D: Placement of autogenous cancellous iliac bone grafts.
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Figure 23-26
Technique of occipitocervical arthrodesis used when the posterior arch of C1 is absent.
A: Exposure of the occiput, atlas, and axis. B: Reflection of periosteal flap to cover defect in atlas. C: Decortication of exposed vertebral elements. D: Placement of autogenous cancellous iliac bone grafts.
(From Koop SE, Winter RB, Lonstein JE. The surgical treatment of instability of the upper part of the cervical spine in children and adolescents. J Bone Joint Surg Am. 1984; 66:403, with permission.)
A: Exposure of the occiput, atlas, and axis. B: Reflection of periosteal flap to cover defect in atlas. C: Decortication of exposed vertebral elements. D: Placement of autogenous cancellous iliac bone grafts.
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Preoperative Planning
See p. 859 for preoperative planning for cervical spine injury. 
Positioning
See p. 859 for positioning in cervical spine injury. The patient is placed in a prone position using Gardner-Wells tongs or a halo ring attached to a Mayfield headrest. A radiograph is obtained to evaluate the position of the head and cervical spine in the prone position. The radiograph also aids in identifying landmarks and levels; although once the skin incision is made, the occiput and spinous processes can be palpated. 
Surgical Approach
See p. 860 for posterior approach. 
Technique
A straight posterior incision is made from the occiput to about C3, with care not to expose below C2 to avoid extension of the fusion to lower levels. An epinephrine and lidocaine solution is injected into the cutaneous and subcutaneous tissues to help control local skin and subcutaneous bleeding. The incision is deepened in the midline to the spinous processes of C2. Once identified, the level of the posterior elements of C1 or the dura is more easily found. After C2 is identified, subperiosteal dissection is carried proximally. Extraperiosteal dissection is used to approach the occiput (see Fig. 23-26A). The dura is not completely exposed; if possible, any fat or ligamentous tissue present is left intact. The interspinous ligaments also should be left intact. 
The occipital periosteum is mobilized by making a triangular incision directly on the posterior skull, with the apex posteriorly and the broad base over the foramen magnum region. A flap of 3 or 4 cm at the base can be created. With subperiosteal elevation, the periosteum can be reflected from the occiput to the spinous processes of C2 (see Fig. 23-26B). The apex of the flap is sutured to the spinous process of C2 and is attached laterally to any posterior elements that are present at C1 or other lateral soft tissues. After the periosteum is secured to the bone and any rudimentary C1 ring is exposed subperiosteally, a power burr is used to decorticate the occiput and any exposed portions of C1 and C2 (see Fig. 23-26C). 
Iliac crest bone graft is harvested, and struts of iliac bone are placed across the area on the periosteal flap (see Fig. 23-26D). No internal fixation is used other than sutures to secure the periosteum. The wound is closed in a routine fashion, and a body jacket or cast is applied and attached to the halo (Table 23-9). 
 
Table 23-9
Occiput to C2 Arthrodesis without Internal Fixation
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Table 23-9
Occiput to C2 Arthrodesis without Internal Fixation
Surgical Steps
  •  
    Make incision from occiput to C3
  •  
    Identify C2
  •  
    Dissect subperiosteally proximally and extraperiosteally to approach occiput
  •  
    Mobilize occipital periosteum and reflect from occiput to spinous processes of C2
  •  
    Secure periosteum to bone
  •  
    Decorticate occiput and exposed portions of C1 and C2
  •  
    Harvest iliac crest bone graft and place across periosteal flap
  •  
    No internal fixation is used
  •  
    Close wound and apply body jacket or cast attached to halo
X
Postoperative Care
The halo cast is worn until radiographs show adequate posterior arthrodesis, usually in 8 to 12 weeks. 

Surgical Procedure: Occiput to C2 Arthrodesis with Triple-Wire Fixation

In patients in whom the posterior elements of C1 and C2 are intact, a triple wire technique, as described by Wertheim and Bohlman,311 can be used (Fig. 23-27). The wires are passed through the outer table of the skull at the occipital protuberance. Because the transverse and superior sagittal sinuses are cephalad to the protuberance, they are not endangered by wire passage. 
Figure 23-27
Technique of occipitocervical arthrodesis used in older adolescents with intact posterior elements of C1 and C2.
 
A: A burr is used to create a ridge in the external occipital protuberance, and then a hole is made in the ridge. B: Wires are passed through the outer table of the occiput, under the arch of the atlas, and through the spinous process of the axis. C: Corticocancellous bone grafts are placed on the wires. D: Wires are tightened to secure grafts in place.
 
(From Wertheim SB, Bohlman HH. Occipitocervical fusion: indications, technique, and long-term results. J Bone Joint Surg Am. 1987; 69:833, with permission.)311
A: A burr is used to create a ridge in the external occipital protuberance, and then a hole is made in the ridge. B: Wires are passed through the outer table of the occiput, under the arch of the atlas, and through the spinous process of the axis. C: Corticocancellous bone grafts are placed on the wires. D: Wires are tightened to secure grafts in place.
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Figure 23-27
Technique of occipitocervical arthrodesis used in older adolescents with intact posterior elements of C1 and C2.
A: A burr is used to create a ridge in the external occipital protuberance, and then a hole is made in the ridge. B: Wires are passed through the outer table of the occiput, under the arch of the atlas, and through the spinous process of the axis. C: Corticocancellous bone grafts are placed on the wires. D: Wires are tightened to secure grafts in place.
(From Wertheim SB, Bohlman HH. Occipitocervical fusion: indications, technique, and long-term results. J Bone Joint Surg Am. 1987; 69:833, with permission.)311
A: A burr is used to create a ridge in the external occipital protuberance, and then a hole is made in the ridge. B: Wires are passed through the outer table of the occiput, under the arch of the atlas, and through the spinous process of the axis. C: Corticocancellous bone grafts are placed on the wires. D: Wires are tightened to secure grafts in place.
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Preoperative Planning
See p. 859 for preoperative planning in cervical spine injury. 
Positioning
For positioning see p. 859. The patient is placed prone, and a lateral radiograph is obtained to document proper alignment. The subcutaneous tissues are injected with an epinephrine solution (1:500,000). 
Surgical Approach
See p. 860 for posterior approach. 
Technique
A midline incision is made extending from the external occipital protuberance to the spine of the third cervical vertebra. The paraspinous muscles are sharply dissected subperiosteally with a scalpel, and a periosteal elevator is used to expose the occiput and cervical laminae, with special care to stay in the midline to avoid the paramedian venous plexus. 
At a point 2 cm above the rim of the foramen magnum, a high-speed diamond burr is used to create a trough on either side of the protuberance, making a ridge in the center (see Fig. 23-27A). A towel clip is used to make a hole in this ridge through only the outer table of bone. A 20-gauge wire is looped through the hole and around the ridge; then another 20-gauge wire is looped around the arch of the atlas. A third wire is passed through a hole drilled in the base of the spinous process of the axis and around this structure, giving three separate wires to secure the bone grafts on each side of the spine (see Fig. 23-27B). 
A thick, slightly curved graft of corticocancellous bone of premeasured length and width is removed from the posterior iliac crest. The graft is divided horizontally into two pieces, and three holes are drilled into each graft (see Fig. 23-27C). The occiput is decorticated and the grafts are anchored in place with the wires on both sides of the spine (see Fig. 23-27D). Additional cancellous bone is packed around and between the two grafts. The wound is closed in layers over suction drains (Table 23-10). 
 
Table 23-10
Occiput to C2 Arthrodesis with Triple-Wire Fixation
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Table 23-10
Occiput to C2 Arthrodesis with Triple-Wire Fixation
Surgical Steps
  •  
    Expose occiput and cervical laminae avoiding the paramedian venous plexus
  •  
    Create trough on either side of occipital protuberance and make a hole in the outer table of bone of the ridge created
  •  
    Pass three wires to secure bone graft
  •  
    Harvest bone graft from iliac crest and divide into two pieces
  •  
    Drill three holes in each graft
  •  
    Decorticate occiput and anchor grafts with the wires and pack with cancellous bone
  •  
    Close wound in layers
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Postoperative Care
Either a rigid cervical orthosis or a halo cast is worn for 6 to 12 weeks, followed by a soft collar that is worn for an additional 6 weeks. 

Surgical Procedure: Occipitocervical Arthrodesis

Preoperative Planning
See p. 859 for preoperative planning in cervical spine injury. 
Positioning
See p. 859 for positioning in cervical spine injury. A halo ring is applied initially with the patient supine. The patient is carefully placed in the prone position, the halo is secured to the operating table with a halo positioning device, and the alignment of the occiput and the cervical spine is confirmed with a lateral radiograph. 
Surgical Approach
See p. 860 for posterior approach. 
Technique
The midline is exposed from the occiput to the second or third cervical vertebra. Particular care is taken to limit the lateral dissection to avoid damaging the vertebral arteries.87 Four holes, aligned transversely, with two on each side of the midline, are made with a high-speed drill through both cortices of the occiput, leaving a 1-cm osseous bridge between the two holes of each pair. The holes are placed caudal to the transverse sinuses. A trough is fashioned into the base of the occiput to accept the cephalad end of the bone graft. A corticocancellous graft is obtained from the iliac crest and is shaped into a rectangle, with a notch created in the inferior base to fit around the spinous process of the second or third cervical vertebra. The caudal extent of the intended arthrodesis (the second or third cervical vertebra) is determined by the presence or absence of a previous laminectomy, congenital anomalies, or the level of the instability. On each side, a looped 16- or 18-gauge Luque wire is passed through the burr holes and looped on itself. Wisconsin button wires (Zimmer, Warsaw, IN) are passed through the base of the spinous process of either the second or the third cervical vertebra. The wire that is going into the left arm of the graft is passed through the spinous process from right to left. The graft is placed into the occipital trough superiorly and about the spinous process of the vertebra that is to be at the caudal level of the arthrodesis (the second or third cervical vertebrae). The graft is precisely contoured so that it fits securely into the occipital trough and around the inferior spinous process before the wires are tightened. The wires are subsequently crossed, twisted, and cut. An intraoperative radiograph is made at this point to assess the position of the graft and the wires as well as the alignment of the occiput and the cephalad-cervical vertebrae. Extension of the cervical spine can be controlled by positioning of the head with the halo frame, by adjustment of the size and shape of the graft, and to a lesser extent by appropriate tightening of the wires (Fig. 23-28 and Table 23-11). 
Figure 23-28
Occipitocervical arthrodesis.
 
A: Four burr holes are placed into the occiput in transverse alignment, with two on each side of the midline, leaving a 1-cm osseous bridge between the two holes of each pair. A trough is fashioned into the base of the occiput. B: Sixteen- or 18-gauge Luque wires are passed through the burr holes and looped on themselves. Wisconsin button wires are passed through the base of the spinous process of either the second or third cervical vertebra. The graft is positioned into the occipital trough and spinous process of the cervical vertebra at the caudal extent of the arthrodesis. The graft is locked into place by the precise contouring of the bone. C: The wires are crossed, twisted, and cut. The extension of the cervical spine can be controlled by positioning of the head with the halo frame, by adjustment of the size and shape of the bone graft, and to a lesser extent by tightening of the wires.
 
(From Dormans JP, Drummond DS, Sutton LN, et al. Occipitocervical arthrodesis in children. J Bone Joint Surg Am. 1995; 77:1234–1240, with permission.)72
A: Four burr holes are placed into the occiput in transverse alignment, with two on each side of the midline, leaving a 1-cm osseous bridge between the two holes of each pair. A trough is fashioned into the base of the occiput. B: Sixteen- or 18-gauge Luque wires are passed through the burr holes and looped on themselves. Wisconsin button wires are passed through the base of the spinous process of either the second or third cervical vertebra. The graft is positioned into the occipital trough and spinous process of the cervical vertebra at the caudal extent of the arthrodesis. The graft is locked into place by the precise contouring of the bone. C: The wires are crossed, twisted, and cut. The extension of the cervical spine can be controlled by positioning of the head with the halo frame, by adjustment of the size and shape of the bone graft, and to a lesser extent by tightening of the wires.
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Figure 23-28
Occipitocervical arthrodesis.
A: Four burr holes are placed into the occiput in transverse alignment, with two on each side of the midline, leaving a 1-cm osseous bridge between the two holes of each pair. A trough is fashioned into the base of the occiput. B: Sixteen- or 18-gauge Luque wires are passed through the burr holes and looped on themselves. Wisconsin button wires are passed through the base of the spinous process of either the second or third cervical vertebra. The graft is positioned into the occipital trough and spinous process of the cervical vertebra at the caudal extent of the arthrodesis. The graft is locked into place by the precise contouring of the bone. C: The wires are crossed, twisted, and cut. The extension of the cervical spine can be controlled by positioning of the head with the halo frame, by adjustment of the size and shape of the bone graft, and to a lesser extent by tightening of the wires.
(From Dormans JP, Drummond DS, Sutton LN, et al. Occipitocervical arthrodesis in children. J Bone Joint Surg Am. 1995; 77:1234–1240, with permission.)72
A: Four burr holes are placed into the occiput in transverse alignment, with two on each side of the midline, leaving a 1-cm osseous bridge between the two holes of each pair. A trough is fashioned into the base of the occiput. B: Sixteen- or 18-gauge Luque wires are passed through the burr holes and looped on themselves. Wisconsin button wires are passed through the base of the spinous process of either the second or third cervical vertebra. The graft is positioned into the occipital trough and spinous process of the cervical vertebra at the caudal extent of the arthrodesis. The graft is locked into place by the precise contouring of the bone. C: The wires are crossed, twisted, and cut. The extension of the cervical spine can be controlled by positioning of the head with the halo frame, by adjustment of the size and shape of the bone graft, and to a lesser extent by tightening of the wires.
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Table 23-11
Occipitocervical Arthrodesis
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Table 23-11
Occipitocervical Arthrodesis
Surgical Steps
  •  
    Expose midline from occiput to second or third cervical vertebra
  •  
    Create four transverse holes, two on each side of midline of occiput
  •  
    Create trough into base of occiput to accept bone graft
  •  
    Shape bone graft from iliac crest into rectangle
  •  
    Determine caudal extent of arthrodesis
  •  
    Pass wires
  •  
    Place precisely contoured graft into occipital trough and spinous process at caudal level of arthrodesis
  •  
    Cross, twist, and cut wires
  •  
    Assess position of graft and alignment
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Surgical Procedure: Atlantooccipital Arthrodesis

Although most patients with atlantooccipital dislocations are treated with fusion from the occiput to C2 or lower, Sponseller and Cass279 described occiput–C1 fusion in two children with atlantooccipital arthrodesis who had complete or near-complete neurologic preservation. Their rationale was that rotation would be preserved by sparing the C1 to C2 articulation from fusion and that less stress would be concentrated on the lower cervical spine by fusing one level instead of two. In both of their patients, stable fusion was obtained and neurologic status was maintained. 
Preoperative Planning
See p. 859 for preoperative planning in cervical spine injury. Before surgery, radiographs and CT scans should be reviewed to be sure a bifid or hypoplastic C1 arch is not present. A halo ring is applied before positioning the patient. 
Positioning
See p. 859 for positioning in cervical spine injury. The patient is placed prone, the halo ring is secured to the operating table with a halo positioning device, and the alignment of the occiput and the cervical spine is confirmed with a lateral radiograph, using a halo ring and attachment. 
Surgical Approach
See p. 860 for posterior approach. 
Technique
The base of the skull to the ring of C1 is exposed, and the periosteum of the skull is elevated so that it forms a flap from the foramen magnum located posteriorly–superiorly. 
The ring of C1 is carefully exposed, with care taken not to dissect more than 1 cm to either side of the midline to protect the vertebral arteries. Care also is taken not to expose any portion of C2 to prevent bridging of the fusion. The dissection of C1 should be done gently. A trough for the iliac crest bone graft is made in the occiput at a level directly cranial to the ring of C1. This trough is unicortical only and extends the width of the exposed portion of C1. Superior to this, two holes are drilled through the occiput as close to the trough as possible to avoid an anteriorly translating vector on the skull when tightening it down to C1. One 22-gauge wire is passed through the holes and another is placed around the ring of C1. The periosteal flap is turned down to bridge the occiput–C1 interval. A small, rectangular, bicortical, iliac crest bone graft approximately 1.5 cm wide and 1 cm high is shaped to fit the trough in the occiput; the graft is contoured to fit the individual patient's occiput–C1 interval. The inferior surface of the bone graft is contoured to fit snugly around the ring of C1 to keep it from migrating anteriorly into the epidural space. Two holes are drilled directly above the distal end of the graft, and the wire around C1 is passed through these holes, forming two distal strands; the wire passed through the occiput forms two proximal strands. These are twisted together and sequentially tightened to apply slight compression to the bone graft. This keeps the graft in the occipital trough and prevents migration into the canal by the occiput. Additional cancellous bone is added to any available space (Table 23-12). 
 
Table 23-12
Atlantooccipital Arthrodesis
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Table 23-12
Atlantooccipital Arthrodesis
Surgical Steps
  •  
    Expose base of skull to ring of C1 and elevate periosteum to create flap
  •  
    Create unicortical trough in occiput at level directly cranial to ring of C1
  •  
    Drill two holes through occiput close to trough
  •  
    Pass wires
  •  
    Bridge occiput-C1 interval with periosteal flap
  •  
    Shape iliac crest bone graft to fit in trough and place graft in occiput-C1 interval
  •  
    Drill two more holes above distal end of graft and pass wires
  •  
    Should form two strands and wire through occiput forms two strands
  •  
    Twist wires together and tighten
  •  
    Add additional cancellous bone to any available space
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Postoperative Care
The halo vest is kept in place for 6 to 8 weeks in a young child and for as long as 12 weeks in an older child or adolescent. Union is confirmed by a lateral radiograph of the posterior occiput–C1 interval and by flexion–extension lateral views. A rigid cervical collar is used for an additional 2 to 4 weeks to protect the fusion and support the patient's cervical muscles while motion is regained. 

Surgical Procedure: Occipitocervical Arthrodesis with Contoured Rod and Segmental Wire

Occipitocervical arthrodesis using a contoured rod and segmental wire has the advantage of achieving immediate stability of the occipitocervical junction (Fig. 23-29), which allows the patient to be immobilized in a cervical collar after surgery, avoiding the need for halo immobilization. 
Figure 23-29
Occipitocervical arthrodesis using a contoured rod and segmental wire or cable fixation.
 
(A, B: Reprinted from Warner WC. Pediatric cervical spine. In: Canale ST, ed. Campbell's Operative Orthopaedics. St. Louis, MO: Mosby, 1998, with permission.)308
(A, B: Reprinted from 


Warner WC
. Pediatric cervical spine. In: 

Canale ST, ed.
Campbell's Operative Orthopaedics. St. Louis, MO: Mosby, 1998, with permission.)308
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Figure 23-29
Occipitocervical arthrodesis using a contoured rod and segmental wire or cable fixation.
(A, B: Reprinted from Warner WC. Pediatric cervical spine. In: Canale ST, ed. Campbell's Operative Orthopaedics. St. Louis, MO: Mosby, 1998, with permission.)308
(A, B: Reprinted from 


Warner WC
. Pediatric cervical spine. In: 

Canale ST, ed.
Campbell's Operative Orthopaedics. St. Louis, MO: Mosby, 1998, with permission.)308
View Original | Slide (.ppt)
X
Preoperative Planning
See p. 859 for preoperative planning in cervical spine injury. 
Positioning
See p. 859 for positioning in cervical spine injury. 
Surgical Approach
See p. 860 for posterior approach to the cervical spine. 
Technique
The base of the occiput and the spinous processes of the upper cervical vertebrae are approached through a longitudinal midline incision, which extends deep within the relatively avascular intermuscular septum. The entire field is exposed subperiosteally. 
A template of the intended shape of the stainless steel rod is made with the appropriate length of Luque wire. Two burr holes are made on each side, about 2 cm lateral to the midline and 2.5 cm above the foramen magnum. Care should be taken to avoid the transverse and sigmoid sinus when making these burr holes. At least 10 mm of intact cortical bone should be left between the burr holes to ensure solid fixation. Luque wires or Songer cables are passed in an extradural plane through the two burr holes on each side of the midline. The wires or cables are passed sublaminar in the upper cervical spine. The rod is bent to match the template; this usually will have a head–neck angle of about 135 degrees and slight cervical lordosis. A Bend Meister (Sofamor/Danek, Memphis, TN) may be helpful in bending the rod. The wires or cables are secured to the rod. The spine and occiput are decorticated, and autogenous cancellous bone grafting is performed (Table 23-13). 
Table 23-13
Occipitocervical Arthrodesis with Contoured Rod and Segmental Wire
Surgical Steps
  •  
    Expose base of occiput to spinous process of upper cervical vertebrae
  •  
    Create a template of intended shape of rod
  •  
    Make two burr holes on each side 2 cm lateral from midline and 2.5 cm above foramen magnum
  •  
    Pass wires or Songer cables
  •  
    Bend rod to match template
  •  
    Secure wires or cables to rod
  •  
    Decorticate spine and occiput and place autogenous cancellous bone graft
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Surgical Procedure: Plate and Rod Fixation Occiput-C2

This technique uses a contoured occipital plate that attaches to a rod for fixation. 
Preoperative Planning
See p. 859 for preoperative planning in cervical spine injury. 
Positioning
See p. 859 for positioning in cervical spine injury. 
Surgical Approach
See p. 860 for posterior approach. 
Technique
Screw fixation is used in the occiput, and, if the anatomy allows, screw fixation may be used at C1 and C2. The occipital plate is positioned in the midline (occipital keel) between the external occipital protuberance and the posterior border of the foramen magnum. The plate is contoured for an anatomic fit against the occiput. Avoid repeated bending of the plate because this may compromise its integrity. It may be necessary to contour the bone of the occiput to allow for an optimal fit of the plate. With an appropriate-size drill bit and guide that match the screw diameter, a hole is drilled into the occiput to the desired predetermined depth. Drilling must be done through the occipital plate to ensure proper drilling depth. Each hole should be completely tapped. The appropriate size occipital screw is inserted and provisionally tightened. The rest of the screws are then inserted and hand-tightened. 
If the anatomy allows, a C1 lateral mass screw and a C2 pedicle screw can be placed. If the anatomy does not allow placement of screws, then sublaminar wires or cables may be used for fixation at C1 and C2. The rods are bent to approximately 130 to 135 degrees to allow attachment to the occipital plate. The rods are placed into the implants and stabilized by tightening the set screws. If cables or sublaminar wires are used, these are tightened to secure the rods to the cervical spine. Final tightening of the occipital plate set screws is performed, and all connections of the final construct are checked before wound closure (Table 23-14). 
 
Table 23-14
Plate and Rod Fixation Occiput to C2
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Table 23-14
Plate and Rod Fixation Occiput to C2
Surgical Steps
  •  
    Expose the occiput and spinous processes of the upper cervical vertebrae
  •  
    Position plate in midline of occiput
  •  
    Contour plate but avoid repeated bending–-may be necessary to contour bone
  •  
    Drill holes in occiput and tap
  •  
    Insert screws and provisionally tighten
  •  
    Place C1 lateral mass screw and C2 pedicle screw or sublaminar cable or wire
  •  
    Bend rod to allow attachment to occipital plate
  •  
    Place rods into implants and tighten
  •  
    Perform final tightening of occipital plate set screws
  •  
    Check all connections
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Postoperative Care
The cervical spine is immobilized in an orthosis for 8 to 12 weeks. 
Pitfalls and Preventative Measures of Surgical Treatment of Atlantooccipital Instability
It is important to remember that acute hydrocephalus can occur after this injury or in the early postoperative period because of changes in cerebrospinal fluid flow at the cranial cervical junction. See p. 860 for further pitfalls with the posterior approach. 

C1-C2 Injuries

Fractures of the Atlas

A fracture of the ring of C1 (Jefferson fracture) is a rare injury and accounts for less than 5% of all cervical spine fractures in children.12,28 

Assessment of Fractures of the Atlas

Mechanisms of Injury of Fractures of the Atlas

This fracture is caused by an axial load applied to the head.20,29,147,150,186,245,293 The force is transmitted through the occipital condyles to the lateral masses of C1, causing a disruption in the ring of C1, usually in two places, with fractures occurring in both the anterior and posterior rings. In children, an isolated single fracture of the ring can occur with the remaining fracture hinging on a synchondrosis.24 This is an important distinction in children because fractures often occur through a normal synchondrosis. In addition, there can be plastic deformation of the ring with no evidence of a fracture.18,150,242,292 This distinction can be seen on plain radiographs and CT scan, with fractures appearing through what appears to be normal physes. As the lateral masses separate, the transverse ligament may be ruptured or avulsed, resulting in C1 and C2 instability.195 If the two lateral masses are widened more than 7 mm beyond the borders of the axis on an anteroposterior radiograph, then an injury to the transverse ligament is presumed. 

Associated Injuries with and Signs and Symptoms of Fractures of the Atlas

Other cervical spine fractures may be present with an atlas fracture, and MRI should be carefully scrutinized to identify other fractures.189 
The classic signs of an atlas fracture in a child are neck pain, cervical muscle spasm, decreased range of motion, and head tilt.150 

Imaging and other Diagnostic Studies of Fractures of the Atlas

Injury to the transverse ligament may be from a rupture of the ligament or an avulsion of the ligament attachment to C1. Jefferson fractures may be evident on plain radiographs, but CT scans are superior at showing this injury (Fig. 23-30). CT scans also can be used to follow the progress of healing. MRI is useful in determining the integrity of the transverse atlantal ligament (TAL) and detecting fractures through the normal synchondroses of the atlas. With a fracture through a synchondrosis, associated edema and hemorrhage are seen on MRI.165 
Figure 23-30
 
A: Initial CT scan through the atlas, demonstrating left anterior synchondrosis diastasis (arrow). B: CT scan 1 month after presentation with callus formation at the synchondrosis, demonstrating healing at the fracture site. C: CT scan 4 months after presentation, showing bony bridging across the fracture site.
 
(From Judd D, Liem LK, Petermann G. Pediatric atlas fracture: A case of fracture through a synchondrosis and review of the literature. Neurosurgery. 2000; 46:991–994, with permission.)
A: Initial CT scan through the atlas, demonstrating left anterior synchondrosis diastasis (arrow). B: CT scan 1 month after presentation with callus formation at the synchondrosis, demonstrating healing at the fracture site. C: CT scan 4 months after presentation, showing bony bridging across the fracture site.
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Figure 23-30
A: Initial CT scan through the atlas, demonstrating left anterior synchondrosis diastasis (arrow). B: CT scan 1 month after presentation with callus formation at the synchondrosis, demonstrating healing at the fracture site. C: CT scan 4 months after presentation, showing bony bridging across the fracture site.
(From Judd D, Liem LK, Petermann G. Pediatric atlas fracture: A case of fracture through a synchondrosis and review of the literature. Neurosurgery. 2000; 46:991–994, with permission.)
A: Initial CT scan through the atlas, demonstrating left anterior synchondrosis diastasis (arrow). B: CT scan 1 month after presentation with callus formation at the synchondrosis, demonstrating healing at the fracture site. C: CT scan 4 months after presentation, showing bony bridging across the fracture site.
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Classification of Fractures of the Atlas

Treatment algorithms for Jefferson fractures are based on the integrity of the TAL. These fractures are considered potentially unstable if the TAL is disrupted. Dickman68 classified these unstable fractures into Type I, an intrasubstance tear of the TAL and Type II, an avulsion fracture of the insertion of the TAL. According to Spence et al.,277 a loss of structural properties of the TAL can occur when the combined overhang of the lateral masses of the atlas extends more than 7 mm beyond the lateral masses of the axis. 

Treatment Options for Fractures of the Atlas

Nonoperative Treatment of Fractures of the Atlas

Most Atlas fractures are stable fractures and treatment consists of immobilization in an orthosis (rigid collar or sternal occipital mandibular immobilizer), Minerva cast, or halo brace. The extent of this immobilization is debatable and should consider the patient's age and cooperation.165 Immobilization usually is for 8 weeks but is based on documented healing by CT imaging and no instability on flexion and extension views. If there is excessive widening (7 mm), halo traction followed by halo brace or cast immobilization is recommended. Stability of C1 to C2 must be documented on flexion and extension lateral radiographs once the fracture is healed (Table 23-15). 
 
Table 23-15
Fractures of the Atlas
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Table 23-15
Fractures of the Atlas
Nonoperative Treatment
Indications Relative Contraindications
Stable atlas fracture Intrasubstance tear of transverse atlantal ligament
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Operative Treatment of Fractures of the Atlas

Surgery rarely is necessary to stabilize these fractures but may be indicated if there is a documented intrasubstance tear of the transverse atlantal ligament (Fig. 23-31). 
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Figure 23-31
CT scan of an atlas fracture.
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Odontoid (Atlantoaxial) Fracture

Odontoid fracture is a relatively common fracture of the cervical spine in children,87 occurring at an average age of 4 years.72,112,264 This fracture accounts for approximately 10% of all cervical spine fractures and dislocations in children. The unique feature of odontoid fractures in children is that the fracture most commonly occurs through the synchondrosis of C2 distally at the base of the odontoid. This synchondrosis is a cartilage line at the base of the odontoid and looks like a physeal or Salter–Harris type I injury. Most odontoid injuries are anteriorly displaced and usually have an intact anterior periosteal sleeve that provides some stability to the fracture when immobilized in extension and allows excellent healing of the fracture.12,246,257,268 Growth disturbances are uncommon after this type of fracture. This synchondrosis normally closes at about 3 to 6 years of age and adds little to the longitudinal growth of C2. 

Assessment of Odontoid Fracture

Mechanism Injury of Odontoid Fracture

A fracture of the odontoid usually is associated with head trauma from a motor vehicle accident or a fall from a height, although it also can occur after trivial head trauma.261 Odent et al.214 reported that 8 of 15 odontoid fractures in children were the result of motor vehicle accidents, with the child fastened in a forward-facing seat. The sudden deceleration of the body as it is strapped into the car seat while the head continues to travel forward causes this fracture. 

Associated Injuries with and Signs and Symptoms of Odontoid Fracture

Head and facial trauma may be associated with odontoid fracture. Radiographs should be obtained in any child complaining of neck pain. Clinically, children with odontoid fractures complain of neck pain and resist attempts to extend the neck. 

Imaging and Other Diagnostic Studies for Odontoid Fracture

Most often, the diagnosis is made by viewing the plain radiographs. Anteroposterior views usually appear normal, and the diagnosis must be made from lateral views because displacement of the odontoid usually occurs anteriorly. Plain radiographs sometimes can be misleading when the fracture occurs through the synchondrosis and has spontaneously reduced. When this occurs, the fracture has the appearance of a nondisplaced Salter–Harris type I fracture. CT scans with three-dimensional reconstruction views may be needed to fully delineate the injury.269 MRI also may be useful to diagnose nondisplaced fractures by detecting edema around the injured area, indicating that a fracture may have occurred. Flexion and extension views to demonstrate instability may be obtained if a nondisplaced fracture is suspected. These studies should be done only in a cooperative child and under the direct supervision of the treating physician. 

Classification of Odontoid Fracture

Odontoid fractures have been classified in adults by location.8 Type I (<5%) occurs at the tip of dens at the insertion of alar ligament that connects the dens to the occiput. Type II (>60%) is a fracture at the base of the dens at its attachment to the body of C2. Type III (30%) does not actually involve the dens but is subdentate through the body of C2. Other fractures include a rare longitudinal fracture through dens and body of C2. This classification is useful in older children and adolescents after the C2 synchondrosis has fused. Prior to this most odontoid fractures in children occur through the synchondrosis 

Outcome Measures for Odontoid Fracture

Odontoid fractures in children generally heal uneventfully and rarely have complications. Neurologic deficits rarely have been reported after this injury.214,284 Odent et al.214 described neurologic injuries in 8 of 15 patients, although most were stretch injuries to the spinal cord at the cervical thoracic junction and not at the level of the odontoid fracture. 

Treatment Options for Odontoid Fracture

Nonoperative Treatment of Odontoid Fracture

Treatment of odontoid fractures is by closed reduction (usually extension or slight hyperextension of the neck), although complete reduction of the translation is not necessary. At least 50% apposition should be obtained to provide adequate cervical alignment, and then the patient should be immobilized in a Minerva or halo cast or custom orthosis. This fracture will heal in about 6 to 8 weeks. After bony healing, stability should be documented by flexion–extension lateral radiographs. Once the Minerva cast or halo is removed, a cervical collar is worn for 1 to 2 weeks. If an adequate reduction cannot be obtained by recumbency and hyperextension, then a head halter or halo traction is needed (Table 23-16). 
 
Table 23-16
Odontoid Fracture
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Table 23-16
Odontoid Fracture
Nonoperative Treatment
Indications Relative Contraindications
Reducible odontoid fracture Irreducible fracture
Grossly unstable fracture
 

From Warner WC Jr: Pediatric cervical spine. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics. 12th ed., Philadelphia, PA: Elsevier; 2013.

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Operative Treatment of Odontoid Fracture

Rarely, manipulation under general anesthesia is needed for irreducible fractures (Fig. 23-32). Surgery with internal fixation rarely is needed due to the good results that are achieved with conservative treatment in children.110,236,259,266,297 In a grossly unstable fracture, a posterior C1 to C2 fusion and instrumentation may be needed (see pp. 877–881; and Table 23-17 for various fusion techniques).305 
Figure 23-32
Lateral radiograph and CT reconstruction view of odontoid fracture through the synchondrosis of C2.
Note the anterior displacement.
Note the anterior displacement.
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Table 23-17
Posterior Fusion Techniques
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Table 23-17
Posterior Fusion Techniques
Atlantoaxial Fusion
Gallie96
Advantage: One wire passed beneath lamina of C1
Disadvantage: Wire may cause unstable C1 vertebra to displace posteriorly and fuse in dislocated position
Brooks and Jenkins
42
Advantage: Greater resistance to rotational movement, lateral bending, and extension
Disadvantage: Requires sublaminar wires at C1 and C2
HARMS AND MELCHER
124
Advantage: Individual placement of polyaxial screws simplifies technique and involves less risk to C1–C2 facet joint and vertebral artery
Disadvantage: Possible irritation of the C2 ganglion from instrumentation
MAGERL AND SEEMAN
181
Advantage: Significant improvement in fusion rates over traditional posterior wire stabilization and bone grafting techniques
Disadvantage: Technically demanding and must be combined with Gallie or Brooks fusion for maximum stability
Occipitocervical Fusion
CONE AND TURNER; WILLARD AND NICHOLSON; ROGERS
Required when other bony anomalies occur at occipitocervical junction
WERTHEIM AND BOHLMAN311
Wires passed through outer table of skull at occipital protuberance instead of through inner and outer tables near foramen magnum
Lessens risk of danger to superior sagittal and transverse sinuses (which are cephalad to occipital protuberance)
KOOP, WINTER, LONSTEIN163
No internal fixation used
Autogenous corticocancellous iliac bone graft
DORMANS ET AL.
72Stable fixation is achieved by exact fit of autogenous iliac-crest bone graft and fixation of the spinous process with button wire and fixation of the occiput with wires through burr holes
Can be used in high-risk patients (Downs syndrome) with increased stabilization and shorter immobilization time
CONTOURED ROD, SCREW OR CONTOURED PLATE FIXATION
Has the advantage of achieving immediate stability of the occipitocervical junction
 

From Warner WC Jr: Pediatric cervical spine. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics. 12th ed., Philadelphia, PA: Elsevier; 2013.309

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Os Odontoideum

Os odontoideum consists of a round ossicle that is separated from the axis by a transverse gap, which leaves the apical segment without support. 

Assessment of Os Odontoideum

Mechanisms of Injury for Os Odontoideum

Fielding et al.8791 suggested that this was an unrecognized fracture at the base of the odontoid. Some studies have documented normal radiographs of the dens with abnormal radiographs after trivial trauma. This can be explained by a distraction force being applied by the alar ligaments, which pulls the tip of the fractured odontoid away from the base and produces a nonunion.127,143,167,244,260,285,301 Other authors believe this to be of congenital origin because of its association with other congenital anomalies and syndromes.107,270,319 Sankar et al.254 reported that six of their 16 patients had associated congenital anomalies in the cervical spine and only eight of the 16 reported any previous trauma.14 

Associated Injuries with and Signs and Symptoms of Os Odontoideum

Cerebellar infarctions due to vertebrobasilar artery insufficiency caused by an unstable os odontoideum were described by Sasaki et al.255 The presentation of an os odontoideum can be variable. Signs and symptoms can range from a minor to a frank compressive myelopathy or vertebral artery compression. Presenting symptoms may be neck pain, torticollis, or headaches caused by local irritation of the atlantoaxial joint. Neurologic symptoms can be transient or episodic after trauma to complete myelopathy caused by cord compression.74 Symptoms may consist of weakness and loss of balance with upper motor neuron signs, although upper motor neuron signs may be completely absent. Proprioceptive and sphincter dysfunctions also are common. 

Imaging and Other Diagnostic Studies of Os Odontoideum

Os odontoideum usually can be diagnosed on routine cervical spine radiographs, which include an open-mouth odontoid view (Fig. 23-33). Lateral flexion and extension views should be obtained to determine if any instability is present. With os odontoideum, there is a space between the body of the axis and a bony ossicle. The free ossicle of the os odontoideum usually is half the size of a normal odontoid and is oval or round, with smooth sclerotic borders. The space differs from that of an acute fracture in which the space is thin and irregular instead of wide and smooth. The amount of instability should be documented on lateral flexion and extension plain radiographs that allow measurement of both the anterior and posterior displacement of the atlas on the axis. Because the ossicle is fixed to the anterior arch of C1 and moves with the anterior arch of C1 both in flexion and extension, measurement of the relationship of C1 to the free ossicle is of little value because they move as a unit. A more meaningful measurement is made by projecting lines superiorly from the body of the axis to a line projected inferiorly from the posterior border of the anterior arch of the atlas. This gives more information as to the stability of C1 to C2. Another measurement that is very helpful is space available for the cord, which is the distance from the back of the dens to the anterior border of the posterior arch of C1. 
Figure 23-33
Lateral radiograph (A) and open-mouth odontoid radiograph (B) showing os odontoideum.
 
(From Warner WC. Pediatric cervical spine. In: Canale ST, ed. Campbell's Operative Orthopaedics. St. Louis, MO: A Mosby Year Book, 1998:2817, with permission.)
(From 


Warner WC
. Pediatric cervical spine. In: 

Canale ST, ed.
Campbell's Operative Orthopaedics. St. Louis, MO: A Mosby Year Book, 1998:2817, with permission.)
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Figure 23-33
Lateral radiograph (A) and open-mouth odontoid radiograph (B) showing os odontoideum.
(From Warner WC. Pediatric cervical spine. In: Canale ST, ed. Campbell's Operative Orthopaedics. St. Louis, MO: A Mosby Year Book, 1998:2817, with permission.)
(From 


Warner WC
. Pediatric cervical spine. In: 

Canale ST, ed.
Campbell's Operative Orthopaedics. St. Louis, MO: A Mosby Year Book, 1998:2817, with permission.)
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Watanabe, Toyama, and Fujimura described two radiographic measurements that correlate with neurologic signs and symptoms.310 They found that if there is a sagittal plane rotation angle of more than 20 degrees or an instability index of more than 40%, a patient is likely to have neurologic signs and symptoms. The instability index is measured from lateral flexion and extension radiographs. Minimal and maximal distances are measured from the posterior border of the C2 body to the posterior arc of the atlas. The instability index is calculated by the following equation: 
The sagittal plane rotation angle is measured by the change in the atlantoaxial angle between flexion and extension. MRI can be useful in identifying reactive retrodental lesions that can occur with chronic instability. This reactive tissue is not seen on routine radiographs but can be responsible for a decrease in the space available for the spinal cord and compressive myelopathy. 

Classification of Os Odontoideum

Os odontoideum is radiographically classified as either orthotopic (in which the ossicle may appear free and in a relatively anatomic position) or dystopic (in which the ossicle may be fixed to the clivus or to the anterior ring of the atlas). See above discussion on radiographic findings. 

Outcomes Measures for Os Odontoideum

The prognosis of os odontoideum depends on the clinical presentation. The prognosis is good if only mechanical symptoms (torticollis or neck pain) or transient neurologic symptoms exist. It is poor if neurologic deficits slowly progress. 

Treatment Options for Os Odontoideum

Nonoperative Treatment of Os Odontoideum

There is little role for nonoperative treatment because of the potential instability of this injury. 

Operative Treatment of Os Odontoideum

Absolute indications for surgical stabilization include: evidence of spinal instability, neurologic involvement, or intractable pain.303 A general guideline for significant instability may include a posterior ADI of less than 13 mm, sagittal plane rotation angle >20 degrees, and instability index of more than 40%, and C1 to C2 translation of more than 5 mm. Due to the abnormal anatomy and potential instability the treating surgeon may still recommend instrumentation and fusion. 
Surgical Procedure: Posterior Arthrodesis of C1 to C2
Preoperative Planning
See p. 859 for preoperative planning in cervical spine injury. Before arthrodesis is attempted, the integrity of the arch of C1 must be documented by CT scan. Incomplete development of the posterior arch of C1 is uncommon but has been reported to occur with increased frequency in patients with os odontoideum. This may necessitate an occiput to C2 arthrodesis for stability. 
Positioning
See p. 859 for positioning in cervical spine surgery. 
Surgical Approaches
See for posterior approach to the cervical spine. 
Technique
See pp. 866–868 for C1 to C2 arthrodesis. If a C1 to C2 arthrodesis is done, one must be careful not to over reduce the odontoid and cause posterior translation. Care also must be taken in positioning the neck at the time of arthrodesis and when tightening the wires if a Gallie or Brooks arthrodesis is performed to prevent posterior translation (Figs. 23-34 to 23-36). 
Figure 23-34
Posterior translation of atlas after C1 to C2 posterior arthrodesis.
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Figure 23-35
 
A: Lateral radiograph of traumatic C1 to C2 instability. B: Note the increase in the atlanto–dens interval. C: Lateral radiograph after C1 to C2 posterior arthrodesis.
A: Lateral radiograph of traumatic C1 to C2 instability. B: Note the increase in the atlanto–dens interval. C: Lateral radiograph after C1 to C2 posterior arthrodesis.
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Figure 23-35
A: Lateral radiograph of traumatic C1 to C2 instability. B: Note the increase in the atlanto–dens interval. C: Lateral radiograph after C1 to C2 posterior arthrodesis.
A: Lateral radiograph of traumatic C1 to C2 instability. B: Note the increase in the atlanto–dens interval. C: Lateral radiograph after C1 to C2 posterior arthrodesis.
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Figure 23-36
 
MRI (A) and CT scan (B) of 9-year-old girl with os odontoideum. C: After Brooks posterior fusion and transarticular screw fixation.
MRI (A) and CT scan (B) of 9-year-old girl with os odontoideum. C: After Brooks posterior fusion and transarticular screw fixation.
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Figure 23-36
MRI (A) and CT scan (B) of 9-year-old girl with os odontoideum. C: After Brooks posterior fusion and transarticular screw fixation.
MRI (A) and CT scan (B) of 9-year-old girl with os odontoideum. C: After Brooks posterior fusion and transarticular screw fixation.
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Potential Pitfalls and Preventative Measures
See p. 860 for potential pitfalls with the posterior approach. 
Treatment-Specific Outcomes
Brockmeyer et al.41 and Wang et al.306 both reported good results with transarticular screw fixation and fusion in the treatment of children with os odontoideum (see Fig. 23-35). Wang et al.306 reported the use of this technique in children as young as 3 years of age. This technique may be preferred depending on the patient's anatomy and the surgeon's experience. Harms and Melcher.124 and Brecknell and Malham37 reported that a high-riding vertebral artery may make transarticular screw placement impossible in about 20% of patients. 
Traumatic Transverse Ligamentous Disruption
The transverse ligament is the primary stabilizer of an intact odontoid against forward displacement. Secondary stabilizers consist of the apical and alar ligaments, which arise from the tip of the odontoid and pass to the base of the skull. These also stabilize the atlantooccipital joint indirectly.111 The normal distance from the anterior cortex of the dens to the posterior cortex of the anterior ring of C1 is 3 mm in adults and 4.5 mm in children. In children, if the distance is more than 4.5 mm, disruption of the transverse ligament is presumed. The spinal canal at C1 is large compared with other cervical segments and accommodates a large degree of rotation and some degree of pathologic displacement without compromising the spinal cord. Steel282 expressed this as a rule of thirds: the spinal canal at C1 is occupied equally by the spinal cord, odontoid, and a free space, which provides a buffer zone to prevent neurologic injury. Steel282 found that anterior displacement of the atlas that exceeds a distance equal to the width of the odontoid may place the spinal cord at risk. 
Acute rupture of the transverse ligament is rare and reportedly occurs in fewer than 10% of pediatric cervical spine injuries.178,191 However, avulsion of the attachment of the transverse ligament to C1 may occur instead of rupture of the transverse ligament. 

Assessment of Transverse Ligamentous Disruption

Mechanisms of Injury for Traumatic Transverse Ligamentous Disruption

This injury may occur from a fall with a blow to the back of the head or other associated upper cervical spine trauma. 

Associated Injuries with and Signs and Symptoms of Traumatic Transverse Ligamentous Disruption

A patient with disruption of the transverse ligament usually has a history of cervical spine trauma and complains of neck pain, often with notable muscle spasms. 

Imaging and Other Diagnostic Studies for Traumatic Transverse Ligamentous Disruption

Diagnosis is confirmed on lateral radiographs that show an increased ADI. An active flexion view may be required to show instability in cooperative patients with unexplained neck pain or neurologic findings. CT scans are useful to demonstrate avulsion of the transverse ligament from its origins to the bony ring of C1. MRI is also useful in determining the integrity of the transverse atlantal ligament. 

Treatment Options for Traumatic Transverse Ligamentous Disruption

Nonoperative Treatment of Traumatic Transverse Ligamentous Disruption

Nonoperative treatment is not effective for ligamentous disruption. Nondisplaced avulsion injuries with a significant fragment may be treated nonoperatively to allow for bone healing. Stability and bone healing must be documented at the end of the nonoperative period. 

Operative Treatment of Traumatic Transverse Ligamentous Disruption

For acute injuries, reduction in extension is recommended, followed by surgical stabilization of C1 and C2. Depending on what type of instrumentation is feasible, immobilization for 8 to 12 weeks in a Minerva cast, a halo brace, or a cervical orthosis may be needed. Flexion and extension views should be obtained after stabilization to document stability. 

Surgical Procedures for C1-C2 Injuries

Surgical Procedure: Atlantoaxial Arthrodesis (Brooks and Jenkins)

Depending on the anatomy and size of the patient, wire or cables may be used to stabilized C1 and C2. If anatomy allows for placement of screws in C1 and C2 then a screw and rod construct can be used that will allow for more stable fixation. 
Preoperative Planning
See p. 859 for preoperative planning in cervical spine injury. 
Positioning
See p. 859 for positioning in cervical spine injury. The patient is placed prone using Gardner-Wells tongs or a halo ring attached to a Mayfield headrest.42 
Surgical Approach
See p. 860 for posterior approach. 
Technique
A lateral cervical spine radiograph is obtained to ensure proper alignment before surgery. The skin is prepared and draped in a sterile fashion and a solution of epinephrine (1:500,000) is injected intradermally to aid hemostasis. C1 and C2 are exposed through a midline incision. 
With an aneurysm needle, a Mersiline suture is passed from cephalad to caudad on each side of the midline under the arch of the atlas and then beneath the lamina of C2. These serve as guides to introduce two doubled 20-gauge wires or Songer cables. Another technique is to pass the sublaminar wires or cables subperiosteally around the ring of C1 and lamina of C2. The periosteum can be easily elevated with a periosteal elevator and allows for some protection of the spinal cord when passing the wires or cables, since they do not pass directly into the epidural space with this technique. The size of the wire used may vary depending on the size and age of the patient. Two full-thickness bone grafts, approximately 1.25 × 3.5 cm, are harvested from the iliac crest and beveled so that the apex of the graft fits in the interval between the arch of the atlas and the lamina of the axis. Notches are fashioned in the upper and lower cortical surfaces to hold the circumferential wires or cables and prevent them from slipping. The doubled wires or cables are tightened over the graft. The wound is irrigated and closed in layers over suction drains (Table 23-18 and Fig. 23-37). 
 
Table 23-18
Atlantoaxial Arthrodesis (Brooks and Jenkins)
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Table 23-18
Atlantoaxial Arthrodesis (Brooks and Jenkins)
Surgical Steps
  •  
    Expose C1 and C2 through a midline incision
  •  
    Pass sublaminar wires or cables
  •  
    Harvest two full-thickness bone grafts from the iliac crest
  •  
    Bevel grafts to fit in the interval between arch of atlas and lamina of axis
  •  
    Create notches in upper and lower cortical surfaces to hold wires or cables
  •  
    Tighten wires or cables
  •  
    Close wound in layers
X
Figure 23-37
Technique of atlantoaxial arthrodesis (Brooks-Jenkins).
 
A: Wires are inserted under the atlas and axis. B: Full-thickness bone grafts from the iliac crest are placed between the arch of the atlas and the lamina of the axis. C, D: The wires are tightened over the graft and twisted on each side.
 
(Adapted from Brooks AL, Jenkins EB. Atlantoaxial arthrodesis by the wedge compression method. J Bone Joint Surg Am. 1978; 60:279, with permission.)
A: Wires are inserted under the atlas and axis. B: Full-thickness bone grafts from the iliac crest are placed between the arch of the atlas and the lamina of the axis. C, D: The wires are tightened over the graft and twisted on each side.
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Figure 23-37
Technique of atlantoaxial arthrodesis (Brooks-Jenkins).
A: Wires are inserted under the atlas and axis. B: Full-thickness bone grafts from the iliac crest are placed between the arch of the atlas and the lamina of the axis. C, D: The wires are tightened over the graft and twisted on each side.
(Adapted from Brooks AL, Jenkins EB. Atlantoaxial arthrodesis by the wedge compression method. J Bone Joint Surg Am. 1978; 60:279, with permission.)
A: Wires are inserted under the atlas and axis. B: Full-thickness bone grafts from the iliac crest are placed between the arch of the atlas and the lamina of the axis. C, D: The wires are tightened over the graft and twisted on each side.
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Postoperative Care
A halo cast or vest is used for postoperative immobilization for 6 to 8 weeks in a young child and for as long as 12 weeks in an older child or adolescent. 
Potential Pitfalls and Preventative Measures
See p. 860 for potential pitfalls with the posterior approach. 

Surgical Procedure: Atlantoaxial Arthrodesis (Gallie)

Preoperative Planning
See p. 859 for preoperative planning in cervical spine injury. 
Positioning
See p. 859 for positioning in cervical spine injury. The patient is placed prone using Gardner-Wells tongs or a halo ring attached to a Mayfield headrest.96 
Surgical Approach
See p. 860 for posterior approach. 
Technique
A lateral cervical spine radiograph is obtained to ensure proper alignment before surgery. The skin is prepared and draped in a sterile fashion, and a solution of epinephrine (1:500,000) is injected intradermally to aid hemostasis. 
A midline incision is made from the lower occiput to the level of the lower end of the fusion, extending deeply within the relatively avascular midline structures, the intermuscular septum, or ligamentum nuchae. Care should be taken not to expose any more than the area to be fused to decrease the chance of spontaneous extension of the fusion. 
By subperiosteal dissection, the posterior arch of the atlas and the lamina of C2 are exposed. The muscular and ligamentous attachments from C2 are removed with a curet. Care should be taken to dissect laterally along the atlas to prevent injury to the vertebral arteries and vertebral venous plexus that lie on the superior aspect of the ring of C1, less than 2 cm lateral to the midline. The upper surface of C1 is exposed no farther laterally than 1.5 cm from the midline in adults and 1 cm in children. Decortication of C1 and C2 generally is not necessary. From below, a wire loop of appropriate size is passed upward under the arch of the atlas either directly or with the aid of a Mersiline suture. The Mersiline suture can be passed with an aneurysm needle. The free ends of the wire are passed through the loop, grasping the arch of C1 in the loop. 
A corticocancellous graft is taken from the iliac crest and placed against the lamina of C2 and the arch of C1 beneath the wire. One end of the wire is passed through the spinous process of C2, and the wire is twisted on itself to secure the graft in place. The wound is irrigated and closed in layers with suction drainage tubes (Table 23-19 and Fig. 23-38). 
 
Table 23-19
Atlantoaxial Arthrodesis (Gallie)
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Table 23-19
Atlantoaxial Arthrodesis (Gallie)
Surgical Steps
  •  
    Expose the posterior arch of the atlas and lamina of C2
  •  
    Pass a wire loop under arch of atlas
  •  
    Harvest corticocancellous bone graft from iliac crest
  •  
    Place graft against lamina of C2 and arch of C1 beneath wire
  •  
    Pass wire through spinous process of C2 and twist wire on itself to secure graft
  •  
    Irrigate wound and close in layers
X
Figure 23-38
Wires are passed under the lamina of the atlas and through the spine of the axis and tied over the graft.
 
This method is used most frequently.
 
(From Fielding JW, Hawkins RJ, Ratzan SA. Spine fusion for atlanto-axial instability. J Bone Joint Surg Am. 1976; 58:400, with permission.)
This method is used most frequently.
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Figure 23-38
Wires are passed under the lamina of the atlas and through the spine of the axis and tied over the graft.
This method is used most frequently.
(From Fielding JW, Hawkins RJ, Ratzan SA. Spine fusion for atlanto-axial instability. J Bone Joint Surg Am. 1976; 58:400, with permission.)
This method is used most frequently.
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Postoperative Care
A halo cast or vest is used for postoperative immobilization for 6 to 8 weeks in a young child and for as long as 12 weeks in an older child or adolescent. 
Potential Pitfalls and Preventative Measures
See p. 860 for potential pitfalls with the posterior approach. 

Surgical Procedure: Atlantoaxial Arthrodesis with Posterior C1 to C2 Transarticular Screw Fixation

Posterior C1 to C2 transarticular screw fixation can be used to stabilize the atlantoaxial joint. This technique has the advantage of being biomechanically superior to posterior wiring techniques,131 and postoperative halo vest immobilization usually is not required. The disadvantages of this technique are potential injury to the vertebral artery, its technical difficulty, and the requirement for sublaminar wire and fusion (Brooks or Gallie technique). 
Preoperative Planning
See p. 859 for preoperative planning for cervical spine injury. Preoperative imaging should include plain radiographs, CT scan, MRI, and MRA of the cervical spine. Supervised dynamic lateral flexion and extension views must determine the reducibility of the atlantoaxial joint.192 If an anatomic reduction cannot be obtained, transarticular screws cannot be safely used. MRA can delineate the course of the vertebral artery through the foramen transversarium and its relationship to the surrounding bony architecture. Approximately 20% of patients show anatomic variations in the path of the vertebral artery and osseous anatomy that would preclude transarticular screw placement.1,37,124 
Positioning
See p. 859 for positioning in cervical spine injury. 
Surgical Approach
See p. 860 for posterior approach. 
Technique
The patient is placed prone with the head held in a Mayfield skull clamp or with a halo ring attached to the Mayfield attachment. Under fluoroscopic guidance, proper alignment of the atlantoaxial joint is confirmed. The spine is prepared and draped from the occiput to the upper thoracic spine. The upper thoracic spine must be included in the surgical field to allow percutaneous placement of the transarticular screw. Percutaneous screw placement may be necessary because of the cephalad orientation of the C1 to C2 transarticular screw. 
A midline posterior cervical exposure is made from C1 to C3. 
The C2 inferior facet is used as the landmark for screw entry: the entry point is 2 mm lateral to the medial edge and 2 mm above the inferior border of the C2 facet (Fig. 23-39A). The drill trajectory is angled medially 5 to 10 degrees. On the lateral fluoroscopic radiograph, the drill trajectory is adjusted toward the posterior cortex of the anterior arch of C1. Percutaneous placement of the C1 to C2 facet screws may be necessary if the intraoperative atlantoaxial alignment precludes drilling or placement of screws through the operative incision. After tapping, a 3.5-mm lag screw is placed across the C1 to C2 joint (Fig. 23-39B). Another screw is then placed in exactly the same way on the other side. After placement of the C1 to C2 transarticular screw, a bone graft is harvested from the posterior iliac crest. A traditional posterior C1 to C2 fusion is done using either the Gallie or the Brooks technique (Fig. 23-40 and Table 23-20). 
Figure 23-39
Posterior C1 to C2 transarticular screw fixation.
 
A: Location of entry points in C1 and C2 for screw placement. B: Polyaxial screws placed bicortically into the lateral mass.
 
(From Harms J, Melcher RP. Posterior C1–C2 fusion with polyaxial screw and rod fixation. Spine. 2001; 26:2467–2471, with permission.)
A: Location of entry points in C1 and C2 for screw placement. B: Polyaxial screws placed bicortically into the lateral mass.
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Figure 23-39
Posterior C1 to C2 transarticular screw fixation.
A: Location of entry points in C1 and C2 for screw placement. B: Polyaxial screws placed bicortically into the lateral mass.
(From Harms J, Melcher RP. Posterior C1–C2 fusion with polyaxial screw and rod fixation. Spine. 2001; 26:2467–2471, with permission.)
A: Location of entry points in C1 and C2 for screw placement. B: Polyaxial screws placed bicortically into the lateral mass.
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Figure 23-40
Position of vertebral arteries and position of screws across atlantoaxial joint.
 
(From Menezes AH. Surgical approaches to the craniocervical junction. In: Weinstein SL, ed. Pediatric Spine Surgery. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)
(From 


Menezes AH
. Surgical approaches to the craniocervical junction. In: 

Weinstein SL, ed.
Pediatric Spine Surgery. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)
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Figure 23-40
Position of vertebral arteries and position of screws across atlantoaxial joint.
(From Menezes AH. Surgical approaches to the craniocervical junction. In: Weinstein SL, ed. Pediatric Spine Surgery. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)
(From 


Menezes AH
. Surgical approaches to the craniocervical junction. In: 

Weinstein SL, ed.
Pediatric Spine Surgery. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.)
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Table 23-20
Atlantoaxial Arthrodesis with Posterior C1–C2 Transarticular Screw Fixation
Surgical Steps
  •  
    Expose the spine from C1 to C3
  •  
    Using C2 inferior facet as landmark, entry point for drill is 2 mm lateral to medial edge and 2 m above inferior border of C2 facet
  •  
    Tap hole and place 3.5-mm lag screw across C1–C2 joint on both sides
  •  
    Harvest bone graft from posterior iliac crest
  •  
    Perform C1–C2 fusion using either Brooks or Gallie technique
X
Postoperative Care
The patient is immobilized in a hard cervical collar only; no halo or Minerva cast is used postoperatively. 
Potential Pitfalls and Preventative Measures
The disadvantages of this technique are potential injury to the vertebral artery, its technical difficulty, and the requirement for sublaminar wire and fusion (Brooks or Gallie technique). See p. 860 for potential pitfalls with the posterior approach. 

Surgical Procedure: Atlantoaxial Arthrodesis with Posterior C1 to C2 Polyaxial Screw and Rod Fixation

Harms and Melcher124 described a technique of atlantoaxial stabilization using fixation of the C1 lateral mass and the C2 pedicle with polyaxial screws and rods (Fig. 23-41). This technique has the advantages of minimizing the risk of vertebral artery injury, does not require the use of sublaminar wires, and does not require an intact posterior arch of C1. 
Figure 23-41
 
Radiograph (A) and MRI (B) after fixation with polyaxial screws and rods.
Radiograph (A) and MRI (B) after fixation with polyaxial screws and rods.
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Figure 23-41
Radiograph (A) and MRI (B) after fixation with polyaxial screws and rods.
Radiograph (A) and MRI (B) after fixation with polyaxial screws and rods.
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Preoperative Planning
See p. 859 for preoperative planning for cervical spine injury. 
Positioning
See p. 859 for positioning in cervical spine injury. 
Surgical Approach
See p. 860 for posterior approach to the cervical spine. 
Technique
The patient is placed prone with the head held in a Mayfield skull clamp or with a halo ring attached to the Mayfield attachment. Under fluoroscopic guidance, proper alignment of the atlantoaxial joint is confirmed. The cervical spine is exposed from the occiput to C3. 
The C1 to C2 complex is exposed to the lateral border of the C1 to C2 articulation. The C1 to C2 joint is exposed and opened by dissection over the superior surface of the C2 pars interarticularis. The dorsal root ganglion of C2 is retracted in a caudal direction to expose the entry point for the C1 screw. This entry point is at the midpoint of the C1 lateral mass at its junction with the posterior arch of C1. A 2-mm high-speed burr is used to mark the starting point for the drill. The drill bit is directed in a straight to slightly convergent trajectory in the anteroposterior plane and parallel to the posterior arch of C1 in the sagittal plane. After determining the appropriate screw length, the drill hole is tapped and a 3.5-mm polyaxial screw is inserted. A number 4 Penfield elevator is used to define the medial border of the C2 isthmus or pedicle. The starting point for the C2 pedicle screw is in the superior and medial quadrant of the C2 lateral mass. A C2 pedicle pilot hole is drilled with a 2-mm drill in a 20- to 30-degree convergent and cephalad trajectory, using the superior and medial surface of the C2 pedicle as a guide. The hole is tapped, and a 3.5-mm polyaxial screw of appropriate length is inserted. Fixation of the rods to the polyaxial screws is obtained with locking nuts (Fig. 23-42). C1 and C2 are decorticated posteriorly and cancellous bone from the posterior iliac crest is used for bone graft (Table 23-21). 
Figure 23-42
 
Lateral (A) and posterior (B) views after C1 to C2 fixation by the polyaxial screw and rod technique.
 
(From Harms J, Melcher RP. Posterior C1 to C2 fusion with polyaxial screw and rod fixation. Spine. 2001; 26:2467–2471, with permission.)
Lateral (A) and posterior (B) views after C1 to C2 fixation by the polyaxial screw and rod technique.
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Figure 23-42
Lateral (A) and posterior (B) views after C1 to C2 fixation by the polyaxial screw and rod technique.
(From Harms J, Melcher RP. Posterior C1 to C2 fusion with polyaxial screw and rod fixation. Spine. 2001; 26:2467–2471, with permission.)
Lateral (A) and posterior (B) views after C1 to C2 fixation by the polyaxial screw and rod technique.
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Table 23-21
Atlantoaxial Arthrodesis with Posterior C1–C2 Polyaxial Screw and Rod Fixation
Surgical Steps
  •  
    Expose the spine from the occiput to C3
  •  
    Expose entry point for C1 screw
  •  
    Direct drill bit to midpoint of C1 lateral mass
  •  
    Tap drill hole and insert 3.5-mm polyaxial screw
  •  
    Drill pilot hole for C2 pedicle screw in superior and medial quadrant of C2 lateral mass
  •  
    Tap drill hole and insert a 3.5-mm polyaxial screw into CT
  •  
    Fix rods to polyaxial screws with locking nuts
  •  
    Decorticate C1 and C2 and insert cancellous bone from posterior iliac crest
X
Postoperative Care
Rigid cervical collar immobilization is used postoperatively. 
Potential Pitfalls and Preventative Measures
Disadvantages of this technique are the anatomic limitations of the C1 lateral mass, which may prevent the use of a 3.5-mm screw, and the potential risk of irritation or injury of the C2 ganglion. See p. 860 for potential pitfalls with posterior approach.145 

C1-C2 Injuries Associated with Other Conditions

Atlantoaxial Instability Associated with Congenital Anomalies and Syndromes

Although acute atlantoaxial instability in children is rare, chronic atlantoaxial instability occurs in certain conditions such as juvenile rheumatoid arthritis, Reiter syndrome, Down syndrome, and Larsen syndrome. Bone dysplasia—such as Morquio polysaccharidosis, spondyloepiphyseal dysplasia, and Kniest syndrome—also may be associated with atlantoaxial instability, as well as os odontoideum, Klippel–Feil syndrome, and occipitalization of the atlas.48,65,120,132,161,166,197 Certain cranial facial malformations have high incidences of associated anomalies of the cervical spine, such as Apert syndrome, hemifacial microsomy, and Goldenhar syndrome.272 Treatment recommendations are individualized based on the natural history of the disorder and future risk to the patient. Minimal trauma may result in significant instability and neurologic compromise in patients with these conditions. There has been considerable interest in the incidence and treatment of atlantoaxial instability in children with Down syndrome.5,64,237,238,276,299,317 

Assessment of Atlantoaxial Instability Associated with Congenital Anomalies and Other Conditions

Mechanisms of Injury for Atlantoaxial Instability Associated with Congenital Anomalies and Syndromes

Generalized ligamentous laxity caused by the underlying collagen defect can result in atlantoaxial and atlantooccipital instability in children with Down syndrome. Pizzutillo and Herman233 made a distinction between cervical instability and hypermobility in Down syndrome patients. Instability implies pathologic motion that jeopardizes neurologic integrity. Hypermobility refers to increased excursions that occur in the cervical spine of patients with Down syndrome compared with normal controls but do not result in loss of structural integrity of the anatomical restraints that protect neural tissues. 318 
Atlantoaxial instability has been reported to occur in 10 to 20% of children with Down syndrome.277 Atlantooccipital instability may also occur in patients with Down syndrome. Despite reports of atlantoaxial and atlantooccipital instability in Down syndrome patients, the exact natural history related to this instability is unknown. Differentiating between hypermobility and clinically significant instability in these patients may be difficult. 

Associated Injuries with and Signs and Symptoms of Atlantoaxial Instability Associated with Congenital Anomalies and Syndromes

Cervical instability usually is discovered on routine screening examination or cervical radiographs obtained for other reasons. Neurologic symptoms are present in 1% to 2.6% of patients with cervical instability. Progressive instability leading to neurologic symptoms is most common in boys older than 10.5 years of age. Involvement of the pyramidal tract usually results in gait abnormalities, hyperreflexia, and motor weakness. Other neurologic symptoms include neck pain, occipital headaches, and torticollis. Detailed neurologic examination often is difficult in patients with Down syndrome, and somatosensory-evoked potentials may be beneficial in documenting neurologic involvement. 

Imaging and Other Diagnostic Studies for Atlantoaxial Instability Associated with Congenital Anomalies and Syndromes

Radiographic examination should include anteroposterior, flexion and extension lateral, and odontoid views. CT scans in flexion and extension or cineradiography in flexion and extension may be needed to evaluate the occipitoatlantal joint and the atlantoaxial joint for instability. MRI may help to demonstrate spinal cord signal changes in suspected instability and neurologic compromise in patients in whom it is often difficult to obtain a detailed neurologic examination. Radiographic evidence of atlantooccipital instability is not as well defined as that for atlantoaxial instability, but measurements described by Wackenheim (see Fig. 23-2), Wiesel and Rothman (Fig. 23-43), Powers (See Fig. 23-1), and Tredwell et al.295 are helpful. A Powers ratio of more than 1.0 is indicative of abnormal anterior translation of the occiput, and a ratio of less than 0.55 indicates posterior translation. However, some studies have reported the poor reliability and reproducibility of these measurements in Down syndrome. CT scans in flexion and extension or cineradiography may be needed to give better detail and information about possible atlantooccipital instability. An ADI of 4.5 to 5 mm indicates instability in normal pediatric patients. An increased ADI in patients with Down syndrome has not been directly correlated with an increase in neurologic compromise. This suggests that radiographs of the cervical spine in Down syndrome must be evaluated by standards specific to that population and not by standards for general pediatric patients because this may result in overdiagnosis of a pathologic process. Neurologic compromise occurs with a similar incidence in individuals with Down syndrome who have a normal ADI and those with an ADI from 4 to 10 mm. In Down syndrome, an ADI of less than 4.5 mm is normal; an ADI of 4.5 to 10 mm is considered hypermobile but not unstable unless there are neurologic findings; and an ADI of more than 10 mm is considered unstable; the patient is at risk for neurologic compromise because of the decrease in the space available for the spinal cord. 
Figure 23-43
Atlantooccipital instability measurement according to Wiesel and Rothman.
 
Lines are drawn on flexion and extension lateral radiographs. Translation should be no more than 1 mm. Atlantal line joins points 1 and 2. Line drawn perpendicular to atlantal line at posterior margin of anterior arch of atlas. Point 3 is basion. Distance from point 3 to perpendicular line is measured in flexion and extension. Differences represent anteroposterior translation.
 
(Adapted from Warner WC Jr. Pediatric cervical spine. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics. 12th edition, Philadelphia, PA: Elsevier, 2013.)
Lines are drawn on flexion and extension lateral radiographs. Translation should be no more than 1 mm. Atlantal line joins points 1 and 2. Line drawn perpendicular to atlantal line at posterior margin of anterior arch of atlas. Point 3 is basion. Distance from point 3 to perpendicular line is measured in flexion and extension. Differences represent anteroposterior translation.
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Figure 23-43
Atlantooccipital instability measurement according to Wiesel and Rothman.
Lines are drawn on flexion and extension lateral radiographs. Translation should be no more than 1 mm. Atlantal line joins points 1 and 2. Line drawn perpendicular to atlantal line at posterior margin of anterior arch of atlas. Point 3 is basion. Distance from point 3 to perpendicular line is measured in flexion and extension. Differences represent anteroposterior translation.
(Adapted from Warner WC Jr. Pediatric cervical spine. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics. 12th edition, Philadelphia, PA: Elsevier, 2013.)
Lines are drawn on flexion and extension lateral radiographs. Translation should be no more than 1 mm. Atlantal line joins points 1 and 2. Line drawn perpendicular to atlantal line at posterior margin of anterior arch of atlas. Point 3 is basion. Distance from point 3 to perpendicular line is measured in flexion and extension. Differences represent anteroposterior translation.
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Classification of Atlantoaxial Instability Associated with Congenital Anomalies and Syndromes

See p. 873 for discussion on atlantoaxial injuries. 

Treatment Options for Atlantoaxial Instability Associated with Congenital Anomalies and Syndromes

Nonoperative Treatment of Atlantoaxial Instability Associated with Congenital Anomalies and Syndromes

Hypermobility of the occipitoatlantal junction has been observed in more than 60% of patients with Down syndrome, but this usually is not associated with neurologic risk. If hypermobility of this joint is documented but the patient is neurologically normal, then high-risk activities should be restricted. When the ADI is less than 4.5 mm, no restriction of activities is necessary. In those who have an ADI of 4.5 to 10 mm, with no neurologic symptoms, high-risk activities also are restricted (Table 23-22). 
 
Table 23-22
Atlantoaxial Instability Associated with Down Syndrome
View Large
Table 23-22
Atlantoaxial Instability Associated with Down Syndrome
Nonoperative Treatment
Indications Relative Contraindications
ADI 4.5–10 mm with no neurologic symptoms Hypermobility
Neurologic deficit
Abnormal MRI signal change in spinal cord
ADI more than 10 mm
X

Operative Treatment of Atlantoaxial Instability Associated with Congenital Anomalies and Syndromes

If there is hypermobility and a neurologic deficit or an abnormal signal change in the spinal cord on MRI, then an occiput to C2 or C3 fusion is recommended. If there is a neurologic deficit or spinal cord changes on MRI, a C1 to C2 fusion is indicated (See pp. 877–881). If the ADI is 10 mm or more, posterior fusion and wiring are recommended (See pp. 866–867). 
Surgical Procedure
See pp. 877–881 for surgical procedures. Before fusion and passage of the wire, the unstable C1 to C2 joint should be reduced by traction. If reduction cannot be obtained, an in situ fusion reduces the risk of neurologic compromise, which may occur if intraoperative reduction is performed and the wires are passed through a narrowed space available for the spinal cord. 
Postoperative Care
Postoperative immobilization in a halo cast or halo vest should be continued for as long as possible because graft resorption 6 months after fusion has been reported. More stable fixation may decrease this complication. C1 to C2 transarticular screw fixation or occiput to C2 instrumentation with plates and rods can be used successfully. 
Potential Pitfalls and Preventative Measures
See p. 860 for potential pitfalls with posterior approach. 
Treatment-Specific Outcomes
Complications are relatively common after cervical fusions in children with Down syndrome. Segal et al.263 reported frequent graft resorption after 10 posterior fusions and suggested as causes inadequate inflammatory response and collagen defects. Msall et al.202 reported the frequent development of instability above and below C1 to C2 fusion in patients with Down syndrome. 

Atlanto-Rotatory Subluxation

Atlantoaxial rotatory subluxation is a common cause of childhood torticollis. This condition is known by several names, such as rotatory dislocation, rotatory displacement, rotatory subluxation, and rotatory fixation. Atlantoaxial rotatory subluxation probably is the most accepted term used, except for long-standing cases (3 months), which are called rotatory fixation. 
A significant amount of motion occurs at the atlantoaxial joint; half of the rotation of the cervical spine occurs there. Through this range of motion at the C1 to C2 articulation, some children develop atlantoaxial rotatory subluxation. Differential diagnoses include torticollis caused by ophthalmologic problems, sternocleidomastoid tightness from muscular torticollis, brain stem or posterior fossa tumors or abnormalities, congenital vertebral anomalies, and infections of the vertebral column. 

Assessment of Atlanto-Rotatory Subluxation

Mechanisms of Injury for Atlanto-Rotatory Subluxation

The two most common causes are trauma and infection; the most common cause is an upper respiratory infection (Grisel syndrome).312 Subluxation also can occur after a retropharyngeal abscess, tonsillectomy, pharyngoplasty, or trivial trauma. There is free blood flow between the veins and lymphatics draining the pharynx and the periodontoid plexus.228 Any inflammation of these structures can lead to attenuation of the synovial capsule or transverse ligament or both, with resulting instability. Another potential etiologic factor is the shape of the superior facets of the axis in children. Kawabe et al.154 showed that the facets are smaller and more steeply inclined in children than in adults. A meniscus-like synovial fold was found between C1 and C2 that could prohibit reduction after displacement has occurred. Although atlantoaxial rotatory subluxation is most commonly seen from inflammatory syndromes, it also can occur after trauma. 

Associated Injuries with and Signs and Symptoms of Atlanto-Rotatory Subluxation

If the cause is traumatic, other spine and head injuries may be associated. Clavicular fracture associated with atlanto-rotatory subluxation also has been described.206 
Clinical findings include neck pain, headache, and a cock-robin position of rotating to one side, as well as lateral flexion to the other (Fig. 23-44). When rotatory subluxation is acute, the child resists attempts to move the head and has pain with any attempts at correction. Usually, the child is able to make the deformity worse but cannot correct it. Associated muscle spasms of the sternocleidomastoid muscle occur predominantly on the side of the long sternocleidomastoid muscle in an attempt to correct the deformity. If the deformity becomes fixed, the pain subsides but the torticollis and the decreased range of motion will persist.89 If rotatory fixation has been present for a long time in a small child, plagiocephaly is sometimes noted. Neurologic abnormalities are extremely rare, although a few cases have been reported. 
Figure 23-44
Child with rotary subluxation of C1 on C2.
 
Note the direction of head tilt and rotation of the neck.
Note the direction of head tilt and rotation of the neck.
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Figure 23-44
Child with rotary subluxation of C1 on C2.
Note the direction of head tilt and rotation of the neck.
Note the direction of head tilt and rotation of the neck.
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Imaging and Other Diagnostic Studies for Atlanto-Rotatory Subluxation

Adequate radiographs may be difficult to obtain because of the associated torticollis and difficulty in positioning the head and neck. Anteroposterior and open-mouth odontoid views should be taken with the shoulders flat and the head in as neutral a position as possible.182 Lateral masses that have rotated forward appear wider and closer to the midline, whereas the opposite lateral mass appears narrower and farther away from the midline on this view. One of the facet joints may be obscured because of apparent overlapping. The distance between the lateral mass and the dens also will be asymmetric. On the lateral view, the lateral facet appears anterior and usually appears wedge-shaped instead of the normal oval shape. The posterior arches of the atlas may fail to superimpose because of head tilt, giving the appearance of fusion of C1 to the occiput (occipitalization). Flexion and extension lateral views are recommended to exclude C1 to C2 instability. 
Cineradiography has been used for the evaluation of atlantoaxial rotatory subluxation.87,91,137 This technique is limited in the acute stage because pain restricts the motion necessary for a satisfactory study. With atlantoaxial rotatory fixation, cine-radiography may be helpful in confirming the diagnosis by showing that the atlas and axis are rotating as a unit. However, this technique requires high radiation exposure and generally has been replaced by CT imaging.12,73,91,98,234 CT should be performed with the head and body positioned as close to neutral as possible. This will show a superimposition of C1 on C2 in a rotated position and will allow the degree and amount of malrotation to be quantified. Some researchers have recommended dynamic CT scans taken with the patient looking to the right and the left to diagnose rotatory fixation.232 McGuire et al.192 classified findings on dynamic CT scans into three stages: stage 0, torticollis but a normal dynamic CT scan; stage 1, limitation of motion with less than 15 degrees difference between C1 and C2, but with C1 crossing the midline; and stage 2, fixed with C1 not crossing the midline. Duration of treatment and intensity of treatment were greater the higher the stage. Three-dimensional CT scans also are helpful in identifying rotatory subluxation.257 Ishii et al.144 reported the use of the lateral inclination angle to grade the severity of subluxation: grade 1, no lateral inclination; grade 2, less than 20 degrees; and grade 3, more 20 degrees (Fig. 23-45). They also noted adaptive changes in the superior facet joint of C2 in grade 3 subluxations and reported that grade 3 subluxations were more commonly irreducible. MRI demonstrates more soft tissue detail, such as associated spinal cord compression, integrity of the transverse atlantal ligament and underlying vertebral or soft tissue infections (Fig. 23-46).248 
Figure 23-45
Classification of chronic atlantoaxial rotatory fixation: grade I, no lateral inclination; grade II, 20 degrees; grade III, 20 degrees.
 
(From Ishii K, Chiba K, Maruiwa H, et al. Pathognomonic radiological signs for predicting prognosis in patients with chronic atlantoaxial rotatory fixation. J Neurosurg Spine. 2006; 5:385–391, with permission.)
(From 


Ishii K,

Chiba K,

Maruiwa H
, et al.
Pathognomonic radiological signs for predicting prognosis in patients with chronic atlantoaxial rotatory fixation.
J Neurosurg Spine.
2006;
5:385–391, with permission.)
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Figure 23-45
Classification of chronic atlantoaxial rotatory fixation: grade I, no lateral inclination; grade II, 20 degrees; grade III, 20 degrees.
(From Ishii K, Chiba K, Maruiwa H, et al. Pathognomonic radiological signs for predicting prognosis in patients with chronic atlantoaxial rotatory fixation. J Neurosurg Spine. 2006; 5:385–391, with permission.)
(From 


Ishii K,

Chiba K,

Maruiwa H
, et al.
Pathognomonic radiological signs for predicting prognosis in patients with chronic atlantoaxial rotatory fixation.
J Neurosurg Spine.
2006;
5:385–391, with permission.)
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X
Figure 23-46
 
A, B: Odontoid view and lateral cervical spine radiograph of rotary subluxation of C1 on C2. C: Note the asymmetry on the open-mouth odontoid view. D: CT and CT reconstruction documenting rotary subluxation.
A, B: Odontoid view and lateral cervical spine radiograph of rotary subluxation of C1 on C2. C: Note the asymmetry on the open-mouth odontoid view. D: CT and CT reconstruction documenting rotary subluxation.
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Figure 23-46
A, B: Odontoid view and lateral cervical spine radiograph of rotary subluxation of C1 on C2. C: Note the asymmetry on the open-mouth odontoid view. D: CT and CT reconstruction documenting rotary subluxation.
A, B: Odontoid view and lateral cervical spine radiograph of rotary subluxation of C1 on C2. C: Note the asymmetry on the open-mouth odontoid view. D: CT and CT reconstruction documenting rotary subluxation.
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Classification of Atlanto-Rotatory Subluxation

Fielding and Hawkins89 classified atlantoaxial rotatory displacements into four types based on the direction and degree of rotation and translation (Fig. 23-47). Type 1 is a unilateral facet subluxation with an intact transverse ligament. This is the most common and benign type. Type 2 is a unilateral facet subluxation with anterior displacement of 3 to 5 mm. The unilateral anterior displacement of one of the lateral masses may indicate an incompetent transverse ligament with potential instability. Type 3 is bilateral anterior facet displacement with more than 5 mm of anterior displacement. This type is associated with deficiencies of the transverse and secondary ligaments, which can result in significant narrowing of the space available for the cord at the atlantoaxial level. Type 4 is an unusual type in which the atlas is displaced posteriorly. This usually is associated with a deficient dens. Although types 3 and 4 are rare, neurologic involvement may be present. Both types must be managed with great care. 
Figure 23-47
Classification of rotary displacement.
 
(From Fielding JW, Hawkins RJ. Atlantoaxial rotary fixation. J Bone Joint Surg Am. 1977; 59:37, with permission.)
(From 


Fielding JW,

Hawkins RJ
.
Atlantoaxial rotary fixation.
J Bone Joint Surg Am.
1977;
59:37, with permission.)
View Original | Slide (.ppt)
Figure 23-47
Classification of rotary displacement.
(From Fielding JW, Hawkins RJ. Atlantoaxial rotary fixation. J Bone Joint Surg Am. 1977; 59:37, with permission.)
(From 


Fielding JW,

Hawkins RJ
.
Atlantoaxial rotary fixation.
J Bone Joint Surg Am.
1977;
59:37, with permission.)
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Treatment Options for Atlanto-Rotatory Subluxation

Nonoperative Treatment of Atlanto-Rotatory Subluxation

Treatment depends on the duration of the symptoms.232 Many patients probably never receive medical treatment because symptoms may be mild and the subluxation may reduce spontaneously over a few days before medical attention is sought. If rotatory subluxation has been present for a week or less, a soft collar, anti-inflammatory medication, and an exercise program are indicated. If this fails to produce improvement and the symptoms persist for more than a week, head halter traction should be initiated. This can be done either at home or in the hospital, depending on the social situation and the severity of symptoms. Muscle relaxants and analgesics also may be needed. Phillips and Hensinger232 found that if rotatory subluxation was present for less than 1 month, head halter traction and bed rest were usually sufficient to relieve symptoms. If the subluxation has been present for longer than a month, successful reduction is not very likely.49 However, halo traction can still be used to try to reduce the subluxation. The halo allows increased traction weight to be applied without interfering with opening of the jaw or causing skin pressure on the mandible. While the traction is being applied, active rotation to the right and left should be encouraged. Once the atlantoaxial rotatory subluxation has been reduced, motion has been restored, and the reduction is documented by CT scan, the patient is maintained in a halo vest for 6 weeks (Table 23-23). 
 
Table 23-23
Atlanto-Rotatory Subluxation
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Table 23-23
Atlanto-Rotatory Subluxation
Nonoperative Treatment
Indications Relative Contraindications
Reducible subluxation Irreducible subluxation
Instability
Neurological deficits
X

Operative Treatment of Atlanto-Rotatory Subluxation

If reduction cannot be maintained, posterior atlantoaxial arthrodesis is recommended.217 Even though internal rotation and alignment of the atlas and axis may not be restored, successful fusion should result in the appearance of normal head alignment by relieving the muscle spasms that occurred in response to the malrotation. Posterior arthrodesis also is recommended if any signs of instability or neurologic deficits secondary to the subluxation are present, if the deformity has been present for more than 3 months, or if conservative treatment of 6 weeks of immobilization has failed. 
Surgical Procedure
Posterior atlantoaxial arthrodesis (See pp. 877–881). 

C2-C3 Injuries

Hangman's Fracture

Bilateral spondylolisthesis of C2, or Hangman's fractures, also may occur in children.234 This injury probably occurs more frequently in this age group because of the disproportionately large head, poor muscle control, and hypermobility. The possibility of child abuse also must be considered.159,241,300 

Assessment of Hangman's Fracture

Mechanism of Injury for Hangman's Fracture

The mechanism of injury is forced hyperextension and axial loading. Most reports of this injury have been in children under the age of 2 years.83,94,139,159,227,234,243,251 

Associated Injuries with and Signs and Symptoms of Hangman's Fracture

Facial and head injuries may be associated. 
Patients present with neck pain and resist any movement of the head and neck. There should be a positive history of trauma (Fig. 23-48). 
Figure 23-48
Lateral radiograph of patient with traumatic C2 spondylolisthesis (Hangman's fracture).
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Imaging and Other Diagnostic Studies for Hangman's Fracture

Radiographs reveal a lucency anterior to the pedicles of the axis, usually with some forward subluxation of C2 on C3. One must be sure this is a fracture and not a persistent synchondrosis of the axis.187,210,275,300,315 Differentiating a persistent synchondrosis from a fracture may be difficult. Several radiographic findings can help distinguish congenital spondylolysis from a Hangman's fracture. With congenital spondylolysis, there should be a symmetrical osseous gap with smooth, clearly defined cortical margins; no prevertebral soft tissue swelling should be observed; and there should be no signs of instability. Often, small foci of ossification are seen in the defect. CT scans show the defect to be at the level of the neurocentral chondrosis. MRI does not show any edema or soft tissue swelling that typically is present with a fracture.199,300 

Classification of Hangman's Fracture

The classification by Effendi et al.,77 which was modified by Levine176 and later by Müller,204 is based on the severity of associated soft tissue injuries. Type I is a bilateral pars fracture with less than 3 mm of anterior C2 to C3 subluxation with intact C2 to C3 discoligamentous complex. It is considered stable. Type II fracture is associated with a discoligamentous injury at C2 to C3 with displacement of the pars fracture and anterior translation of the C2 body. Type IIB is distraction across C2 to C3 disc and flexion angulation of C2–body and dens. Müller subclassified type II fractures as flexion, extension, and listhesis. Type III is a fracture of the pars interarticularis with C2 to C3 facet dislocations. This classification is for adult patients and may not be completely applicable to pediatric patients.176,213 

Treatment Options for Hangman's Fracture

Nonoperative Treatment of Hangman's Fracture

Treatment of stable Hangman's fractures should be with immobilization in a Minerva cast, halo, or cervical orthosis for 8 to 12 weeks. Pizzutillo et al.234 reported that four of five patients healed with immobilization (Table 23-24). 
 
Table 23-24
Hangman's Fracture
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Table 23-24
Hangman's Fracture
Nonoperative Treatment
Indications Relative Contraindications
Stable fracture Nonunion
Documented instability
X

Operative Treatment of Hangman's Fracture

If union does not occur or there is documented instability, a posterior or anterior arthrodesis can be done to stabilize this fracture. Posterior or anterior arthrodesis may be necessary (pp. 877–881). 

Subaxial (C3-C7) Injuries

Fractures and dislocations involving C3 to C7 are rare in children and infants.92,148,190,271 and usually occur in teenagers or older children. Lower cervical spine injuries in children as opposed to those in adults can occur through the cartilaginous endplate.67 The endplate may break completely through the cartilaginous portion (Salter–Harris type I) or may exit through the bony edge (Salter–Harris type II). Usually, the inferior endplate fractures because of the protective effect of the uncinate processes of the superior endplate.16,307 
Depending on the size and anatomy of the patient, adult posterior instrumentation techniques with screw and rods usually can be used in subaxial spine fractures.146 Occasionally, wire fixation may be needed for posterior stabilization of subaxial spine fractures. Posterior instrumentation techniques that are used in the adult spine (plate or rods and lateral mass screws) can be used in the pediatric cervical spine. Before these techniques are used, the size of the lateral masses must be evaluated to ensure that there is adequate room to place these screws. 

Posterior Ligamentous Disruptions
Assessment of Posterior Ligamentous Disruptions

Mechanism of Injury for Posterior Ligamentous Disruption

Posterior ligamentous disruption can occur with a flexion or distraction injury to the cervical spine. 

Associated Injuries with and Signs and Symptoms of Posterior Ligamentous Disruption

Intervertebral disc disruption, facet fracture, and other ligamentous disruptions may be associated with this injury. The patient usually has point tenderness at the injury site and complains of neck pain. 

Imaging and Other Diagnostic Studies for Posterior Ligamentous Disruption

Initial radiographs may be normal except for loss of normal cervical lordosis. This may be a normal finding in young children but should be evaluated for possible ligamentous injury in an adolescent. Widening of the posterior interspinous distance is suggestive of this injury. Guidelines for instability in children have not been fully developed. Instability in adults has been defined as angulation between adjacent vertebrae in the sagittal plane of 11 degrees more than the adjacent normal segment or translation in the sagittal plane of 3.5 mm or more.167,168,237,238 Brockmeyer39 has suggested that more than 7 degrees of kyphotic angulation between adjacent vertebral bodies in the pediatric spine implies an unstable ligamentous injury.200,201 MRI may be helpful in documenting ligamentous damage. 

Classification of Posterior Ligamentous Disruption

The Subaxial Injury Classification (SLIC) and Severity score identifies three major injury characteristics to describe subaxial cervical injuries: injury morphology, discoligamentous complex integrity, and neurologic status (Table 23-25).229 
 
Table 23-25
The SLIC System
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Table 23-25
The SLIC System
Characteristic Points
Morphology
 No abnormality 0
 Compression 1
  Burst +1 = 2
 Distraction (e.g., facet perch, hyperextension) 3
 Rotation/translation (e.g., facet dislocation, unstable teardrop or advanced staged flexion compression injury) 4
DLC
 Intact 0
 Indeterminate (e.g., isolated interspinous widening, MRI signal change only) 1
 Disrupted (e.g., widening of anterior disc space, facet perch or dislocation, kyphotic deformity) 2
Neurologic Status
 Intact 0
 Root injury 1
 Complete cord injury 2
 Incomplete cord injury 3
 Ongoing cord compression (in setting of a neurologic deficit) +1
 

Reproduced with permission from Patel JC, Dailey A, Brodke DS, et al. Subaxial cervical spine trauma classification: The Subaxial Injury Classification system and case examples. Neurosurg Focus. 2008; 25:E8.

X

Treatment Options for Posterior Ligamentous Disruption

Nonoperative Treatment of Posterior Ligamentous Disruption

Posterior ligamentous injuries if stable should be protected with an extension orthosis, and patients should be followed closely for the development of instability (Table 23-26). 
 
Table 23-26
Posterior Ligamentous Disruption
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Table 23-26
Posterior Ligamentous Disruption
Nonoperative Treatment
Indications Relative Contraindications
Stable posterior ligamentous disruption Instability
X

Operative Treatment of Posterior Ligamentous Disruption

If signs of instability are present, then a posterior arthrodesis should be performed (See pp. 891–894). 
Compression Fracture
Compression fractures are stable injuries and heal in children in 3 to 6 weeks. 

Assessment of compression fracture

Mechanisms of Injury for Compression Fracture

Compression fractures, the most common fractures of the subaxial spine in children, are caused by flexion and axial loading that result in loss of vertebral body height. 

Associated Injuries with and Signs and Symptoms of Compression Fracture

Associated injuries can include anterior teardrop, laminar, and spinous process fractures. Pain and neurologic symptoms may be present. 

Imaging and Other Diagnostic Studies for Compression Fracture

These injuries can be detected on a lateral radiograph. Because the vertebral disks in children are more resilient than the vertebral bodies, the bone is more likely to be injured. Many compression fractures may be overlooked because of the normal wedge shape of the vertebral bodies in young children. Flexion and extension films to confirm stability should be obtained 2 to 4 weeks after injury. In children under 8 years of age, the vertebral body may reconstitute itself with growth, although Schwarz et al.262 reported that kyphosis of more than 20 degrees may not correct with growth. 

Classification of Compression Fracture

See Table 23-25 for subaxial cervical spine injury classification. 

Treatment Options for Compression Fracture

Nonoperative Treatment of Compression Fracture

Immobilization in a cervical collar is recommended for 3 to 6 weeks. 

Operative Treatment of Compression Fracture

Operative treatment is not usually necessary. 
Unilateral and Bilateral Facet Dislocations
Unilateral facet dislocations and bilateral facet dislocations are the second most common injuries in the subaxial spine in children. Most occur in adolescents and are similar to adult injuries. 

Assessment of Unilateral and Bilateral Facet Dislocations

Mechanisms of Injury for Unilateral and Bilateral Facet Injury Dislocations

Facet dislocations can occur from a range of injury mechanisms that include hyperflexion, hyperextension, and/or axial rotation injuries from motor vehicle accidents, diving accidents, and falls. 

Associated Injuries with and Signs and Symptoms of Unilateral and Bilateral Facet Dislocations

Cervical spine ligamentous injuries are often associated with bilateral dislocations as well as disc herniations. Bilateral facet dislocation has a high risk of cord damage. 
Unilateral facet dislocation may have minimal localized pain or no symptoms; however, pain and neurologic symptoms are frequent in bilateral dislocations. 

Imaging and Other Diagnostic Studies for Unilateral and Bilateral Facet Dislocations

The diagnosis usually can be made on anteroposterior and lateral radiographs. In children, the so-called perched facet is a true dislocation. The cartilaginous components are overlapped and locked. On the radiograph, the facet appears perched because the overlapped cartilage cannot be seen. 

Classification of Unilateral and Bilateral Facet Dislocations

See Table 23-25 for subaxial spine injury classification. 

Treatment Options for Unilateral and Bilateral Facet Dislocations

Nonoperative Treatment of Unilateral and Bilateral Facet Dislocations

Unilateral facet dislocation is treated with traction and reduction. 

Operative Treatment of Unilateral and Bilateral Facet Dislocations

Indications/Contraindications
If reduction cannot be easily obtained, open reduction and arthrodesis are indicated. Complete bilateral facet dislocation, although rare, is more unstable and has a higher incidence of neurologic deficit (Fig. 23-49). In a patient with bilateral jumped facets and motor-complete spinal cord injury, and emergent reduction followed by immediate MRI to evaluate for an epidural hematoma or herniated disk should be done. In a patient who is neurologically intact or has a motor-incomplete lesion with jumped facets, an urgent MRI is obtained to evaluate for a herniated disk or hematoma in the canal. In the absence of such a lesion, a closed reduction is obtained by traction. After reduction, treatment may consist of either an anterior or posterior instrumentation and arthrodesis (pp. 891–894). 
Figure 23-49
 
A, B: Lateral radiograph of a patient with the so-called perched facets, demonstrating a facet dislocation. C, D: Lateral and anteroposterior radiographs after reduction and posterior arthrodesis.
A, B: Lateral radiograph of a patient with the so-called perched facets, demonstrating a facet dislocation. C, D: Lateral and anteroposterior radiographs after reduction and posterior arthrodesis.
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Figure 23-49
A, B: Lateral radiograph of a patient with the so-called perched facets, demonstrating a facet dislocation. C, D: Lateral and anteroposterior radiographs after reduction and posterior arthrodesis.
A, B: Lateral radiograph of a patient with the so-called perched facets, demonstrating a facet dislocation. C, D: Lateral and anteroposterior radiographs after reduction and posterior arthrodesis.
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Burst Fracture
Although rare, burst fractures can occur in children. 

Assessment of Burst Fracture

Mechanisms of Injury for Burst Fracture

These injuries are caused by an axial load after high-energy trauma. 

Associated Injuries with and Signs and Symptoms of Burst Fracture

Patients may present with pain, deformity, and neurologic symptoms. 

Imaging and Other Diagnostic Studies for Burst Fracture

Radiographic evaluation should consist of anteroposterior and lateral views. CT scans aid in detecting any spinal canal compromise from retropulsed fracture fragments and occult laminar fractures. The posterior aspect of the vertebral body can displace posteriorly, causing canal compromise and neurologic deficit. Loss of body height may be noted on radiographs. 

Classification of Burst Fracture

See Table 23-25 for classification of subaxial injuries. Treatment decisions are based on the severity of deformity, canal compromise, degree of vertebral body height loss, and degree of neurologic deficit. 

Treatment Options for Burst Fracture

Nonoperative Treatment of Burst Fracture

If no neurologic deficit or significant canal compromise is present, treatment consists of traction followed by halo immobilization (Table 23-27). 
 
Table 23-27
Burst Fracture
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Table 23-27
Burst Fracture
Nonoperative Treatment
Indications Relative Contraindications
Burst fracture with no neurologic complications or canal compromise Significant canal compromise
X

Operative Treatment of Burst Fracture

Anterior arthrodesis rarely is recommended in pediatric patients, except in a patient with a burst fracture and significant canal compromise.264 Anterior arthrodesis destroys the anterior growth potential; as posterior growth continues, a kyphotic deformity may occur (Fig. 23-50). In older children and adolescents, anterior instrumentation can be used for stabilization (Fig. 23-51). Anterior instrumentation can be used for stabilization in older children and adolescents when there is significant canal compromise (p. 895). 
Figure 23-50
Anteroposterior and lateral radiographs and CT scan of patient with a minimally displaced burst fracture of C5.
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Figure 23-51
 
Radiograph (A) and MRI (B) of 12-year-old boy with three-column injury sustained during football game. C, D: After anterior and posterior fusion and fixation with anterior plate and screws and posterior instrumentation.
Radiograph (A) and MRI (B) of 12-year-old boy with three-column injury sustained during football game. C, D: After anterior and posterior fusion and fixation with anterior plate and screws and posterior instrumentation.
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Figure 23-51
Radiograph (A) and MRI (B) of 12-year-old boy with three-column injury sustained during football game. C, D: After anterior and posterior fusion and fixation with anterior plate and screws and posterior instrumentation.
Radiograph (A) and MRI (B) of 12-year-old boy with three-column injury sustained during football game. C, D: After anterior and posterior fusion and fixation with anterior plate and screws and posterior instrumentation.
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Spondylolysis and Spondylolisthesis

Spondylolysis and spondylolisthesis of C2 to C6 have been reported. 

Assessment of Spondylolysis and Spondylolisthesis

Mechanisms of Injury for Spondylolysis and Spondylolisthesis

These injuries can occur from either a hyperextension or flexion axial loading injury. 

Associated Injuries with and Signs and Symptoms of Spondylolysis and Spondylolisthesis

Associated anterosuperior avulsion or compression fractures of the vertebral body may occur. Patients may present with shoulder or localized neck pain. 

Imaging and Other Diagnostic Studies for Spondylolysis and Spondylolisthesis

The diagnosis usually is made on plain radiographs that show a fracture line through the pedicles. Oblique views may be necessary to better identify the fracture line. CT imaging and MRI may be useful in differentiating an acute fracture from a normal synchondrosis. 

Classification of Spondylolysis and Spondylolisthesis

See Table 23-5 for SLIC. 

Treatment Options for Spondylolysis and Spondylolisthesis

Nonoperative Treatment of Spondylolysis and Spondylolisthesis

Treatment consists of immobilization in a cervical orthosis or halo brace (Table 23-28). 
 
Table 23-28
Spondylolysis and Spondylolisthesis
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Table 23-28
Spondylolysis and Spondylolisthesis
Nonoperative Treatment
Indications Relative Contraindications
Stable spondylolysis and spondylolisthesis Instability
Nonunion
X

Operative Treatment of Spondylolysis and Spondylolisthesis

Surgical stabilization is recommended only for truly unstable fractures or nonunions. Neurologic involvement is rare. 

Surgical Procedure for Subaxial Injuries

Posterior Arthrodesis (Fig. 23-52)

Figure 23-52
Technique of posterior arthrodesis in subaxial spine levels C3 to C7.
 
A: A hole is made in the spinous process of the vertebrae to be fused. B: An 18-gauge wire is passed through both holes and around the spinous processes. C: The wire is tightened. D: Corticocancellous bone grafts are placed.
 
(From Murphy MJ, Southwick WO. Posterior approaches and fusions. In: Cervical Spine Research Society. The Cervical Spine. Philadelphia, PA: JB Lippincott, 1983:506–507, with permission.)205
A: A hole is made in the spinous process of the vertebrae to be fused. B: An 18-gauge wire is passed through both holes and around the spinous processes. C: The wire is tightened. D: Corticocancellous bone grafts are placed.
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Figure 23-52
Technique of posterior arthrodesis in subaxial spine levels C3 to C7.
A: A hole is made in the spinous process of the vertebrae to be fused. B: An 18-gauge wire is passed through both holes and around the spinous processes. C: The wire is tightened. D: Corticocancellous bone grafts are placed.
(From Murphy MJ, Southwick WO. Posterior approaches and fusions. In: Cervical Spine Research Society. The Cervical Spine. Philadelphia, PA: JB Lippincott, 1983:506–507, with permission.)205
A: A hole is made in the spinous process of the vertebrae to be fused. B: An 18-gauge wire is passed through both holes and around the spinous processes. C: The wire is tightened. D: Corticocancellous bone grafts are placed.
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Preoperative Planning
See p. 859 for preoperative planning. 
Positioning
See p. 859 for position for cervical spine injury. The patient is placed prone using a Mayfield headrest or Gardner-Wells tongs or a halo ring attached to a Mayfield headrest. 
Surgical Approach
See p. 860 for posterior approach to the cervical spine. 
Technique
Radiographs are obtained to confirm adequate alignment of the vertebrae and to localize the vertebrae to be exposed. Extension of the fusion mass can occur when extra vertebrae or spinous processes are exposed in the cervical spine. A midline incision is made over the chosen spinous processes, and the spinous process and lamina are exposed subperiosteally to the facet joints. 
If the spinous process is large enough, a hole is made in the base of the spinous process with a towel clip or Lewin clamp. An 18-gauge wire is passed through this hole, looped over the spinous process, and passed through the hole again. A similar hole is made in the base of the spinous process of the inferior vertebra to be fused, and the wire is passed through this vertebra. The wire is then passed through this hole, looped under the inferior aspect of the spinous process, and then passed back through the same hole. The wire is tightened and corticocancellous bone grafts are placed along the exposed lamina and spinous processes. The wound is closed in layers. If the spinous process is too small to pass wires, then an in situ arthrodesis can be performed and external immobilization used. 
Hall et al.117 used a 16-gauge wire and threaded Kirschner wires. The threaded Kirschner wires are passed through the bases of the spinous processes of the vertebrae to be fused. This is followed by a figure-of-eight wiring with a 16-gauge wire (Fig. 23-53). After tightening the wire about the Kirschner wires, strips of corticocancellous and cancellous bone are packed over the posterior arches of the vertebrae to be fused (Table 23-29). 
Figure 23-53
Alternative fixation method for posterior arthrodesis of C3 to C7.
 
A 16-gauge wire is placed in a figure-of-eight pattern around two threaded Kirschner wires passed through the bases of the spinous processes of the vertebrae to be fused.
 
(From Hall JE, Simmons ED, Danylchuk K, et al. Instability of the cervical spine and neurological involvement in Klippel–Feil syndrome: A case report. J Bone Joint Surg Am. 1990; 72:460, with permission.)118
A 16-gauge wire is placed in a figure-of-eight pattern around two threaded Kirschner wires passed through the bases of the spinous processes of the vertebrae to be fused.
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Figure 23-53
Alternative fixation method for posterior arthrodesis of C3 to C7.
A 16-gauge wire is placed in a figure-of-eight pattern around two threaded Kirschner wires passed through the bases of the spinous processes of the vertebrae to be fused.
(From Hall JE, Simmons ED, Danylchuk K, et al. Instability of the cervical spine and neurological involvement in Klippel–Feil syndrome: A case report. J Bone Joint Surg Am. 1990; 72:460, with permission.)118
A 16-gauge wire is placed in a figure-of-eight pattern around two threaded Kirschner wires passed through the bases of the spinous processes of the vertebrae to be fused.
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Table 23-29
Posterior Arthrodesis for Subaxial Injuries
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Table 23-29
Posterior Arthrodesis for Subaxial Injuries
Surgical Steps
  •  
    Expose the chosen spinous processes with a midline incision
  •  
    Make a hole in the base of the spinous process and in spinous process of inferior vertebra to be fused
  •  
    Pass wire and tighten
  •  
    Place corticocancellous bone graft
  •  
    Close wound in layers
X
Surgical Procedure: Posterior Arthrodesis with Lateral Mass Screw Fixation
Several techniques of lateral mass screw fixation for the lower cervical spine have been described. They differ primarily in the entry points for the screws and in the trajectory of screw placement, which yield different exit points.180,249 
Preoperative Planning
See p. 859 for preoperative planning. 
Positioning
See p. 859 for position for cervical spine injury. The patient is placed prone using a Mayfield headrest or Gardner-Wells tongs or a halo ring attached to a Mayfield headrest. 
Surgical Approach
See p. 860 for posterior approach to the cervical spine. 
Technique (Roy-Camille).250
The entry point for the screw is at the center of the rectangular posterior face of the lateral mass or can be measured 5 mm medial to the lateral edge and midway between the facet joints (Fig. 23-54A). The drill is directed perpendicular to the posterior wall of the vertebral body with a 10-degree lateral angle (Fig. 23-54B). This trajectory establishes an exit point slightly lateral to the vertebral artery and below the exiting nerve root. The lateral mass depth from C3 to C6 ranges from 6 to 14 mm in men (average 8.7 mm) and 6 to 11 mm in women (average 7.9 mm). An adjustable drill guide set to a depth of 10 to 12 mm is used to prevent penetration beyond the anterior cortex. The depth can be gradually and safely increased if local anatomy permits. If the additional 20% of pullout strength with bicortical fixation is desired, the exit point should be at the junction of the lateral mass and the transverse process. Lateral fluoroscopic imaging makes it easier to choose the optimal trajectory and avoid penetration of the subjacent facet joint (Fig. 23-54C), which is especially important at the caudal level of fixation because this joint should be included in the fusion (Table 23-30). 
Figure 23-54
Roy-Camille technique of lateral mass screw insertion.
 
A: Entry point for screw insertion. B: Drill is directed perpendicular to posterior wall of vertebral body with a 10-degree lateral angle. C: Final screw position.
 
(From Heller JG, Jeffords P. Internal fixation of the cervical spine. Posterior instrumentation of the lower cervical spine. In: Frymoyer JW, Wiesel SW, eds. The Adult and Pediatric Spine. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2004, with permission.)
A: Entry point for screw insertion. B: Drill is directed perpendicular to posterior wall of vertebral body with a 10-degree lateral angle. C: Final screw position.
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Figure 23-54
Roy-Camille technique of lateral mass screw insertion.
A: Entry point for screw insertion. B: Drill is directed perpendicular to posterior wall of vertebral body with a 10-degree lateral angle. C: Final screw position.
(From Heller JG, Jeffords P. Internal fixation of the cervical spine. Posterior instrumentation of the lower cervical spine. In: Frymoyer JW, Wiesel SW, eds. The Adult and Pediatric Spine. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2004, with permission.)
A: Entry point for screw insertion. B: Drill is directed perpendicular to posterior wall of vertebral body with a 10-degree lateral angle. C: Final screw position.
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Table 23-30
Posterior Arthrodesis with Lateral Mass Screw Fixation (Roy-Camille)
Surgical Steps
  •  
    Place entry point for screw at center of rectangular posterior face of lateral mass
  •  
    Drill perpendicular to posterior wall to a safe depth
  •  
    Exit point should be at junction of lateral mass and transverse process for additional pullout strength
X
Technique (Magerl)
The entry point for the screw is 1 mm medial and rostral (proximal) to the center point of the posterior surface of the lateral mass (Fig. 23-55A). It is oriented at a 45- to 60-degree rostral angle, parallel to the adjacent facet joint articular surface, and at a 25-degree lateral angle (Fig. 23-55B). This trajectory establishes an exit point lateral to the vertebral artery and above the exiting nerve root while engaging the lateral portion of the ventral cortex of the superior articular facet (Fig. 23-55C). The proper trajectory for this technique is more difficult to achieve that in the Roy-Camille technique. The prominence of the thorax can impede proper alignment of the drill and guide, risking injury to the nerve root if the second cortex is penetrated. The depth of penetration at this angle is approximately 18 mm, compared to 14 mm with the Roy-Camille technique, which has some implications for purchase strength and mode of screw failure (Table 23-31). 
Figure 23-55
Magerl technique of lateral mass screw insertion.
 
A: Entry point for screw insertion. B: Drill is directed at a 25-degree lateral angle. C: Final screw position.
 
(From Heller JG, Jeffords P. Internal fixation of the cervical spine. Posterior instrumentation of the lower cervical spine. In: Frymoyer JW, Wiesel SW, eds. The Adult and Pediatric Spine. 3rd ed. Philadelphia, PA: Lippincott C Williams & Wilkins, 2004, with permission.)
A: Entry point for screw insertion. B: Drill is directed at a 25-degree lateral angle. C: Final screw position.
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Figure 23-55
Magerl technique of lateral mass screw insertion.
A: Entry point for screw insertion. B: Drill is directed at a 25-degree lateral angle. C: Final screw position.
(From Heller JG, Jeffords P. Internal fixation of the cervical spine. Posterior instrumentation of the lower cervical spine. In: Frymoyer JW, Wiesel SW, eds. The Adult and Pediatric Spine. 3rd ed. Philadelphia, PA: Lippincott C Williams & Wilkins, 2004, with permission.)
A: Entry point for screw insertion. B: Drill is directed at a 25-degree lateral angle. C: Final screw position.
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Table 23-31
Posterior Arthrodesis with Lateral Mass Screw Fixation (Magerl)
Surgical Steps
  •  
    Place entry point for screw 1 mm medial and rostral to center point of posterior surface of lateral mass
  •  
    Drill at a 45- to 60-degree rostral angle parallel to adjacent fact joint articular surface and 25-degree lateral angle
  •  
    Depth of penetration is approximately 18 mm
X
Surgical Procedure: Crossed Translaminar Screw Fixation of C2
Crossed translaminar screws may be used for posterior fixation if the lateral masses are not adequate for screw fixation. This has been described for fixation at C2 but can also be used in the lower cervical spine. 
Preoperative Planning
See p. 859 for preoperative planning. 
Positioning
See p. 859 for position for cervical spine injury. The patient is placed prone with the head maintained in the neutral position in a Mayfield head holder. 
Surgical Approach
See p. 860 for posterior approach to the cervical spine. 
Technique
The posterior arch of C1 and the spinous process, laminae, and medial–lateral masses of C2 are exposed. A high-speed drill is used to open a small cortical window at the junction of the C2 spinous process and the lamina on the left, close to the rostral margin of the C2 lamina (Fig. 23-56). With a hand drill, the contralateral (right) lamina is carefully drilled along its length, with the drill visually aligned along the angle of the exposed contralateral laminar surface. A small ball probe is used to palpate the length of the drill hole and verify that no cortical breakthrough into the spinal canal has occurred. A 4-mm diameter polyaxial screw is inserted along the same trajectory. In the final position, the screw head remains at the junction of the spinous process and lamina on the left, with the length of the screw within the right lamina. Next, a small cortical window is made at the junction of the spinous process and lamina of C2 on the right, close to the caudal aspect of the lamina. Using the same technique, a 4-mm diameter screw is placed into the left lamina, with the screw head remaining on the right side of the spinous process (Fig. 23-57). Appropriate rods are then placed into the screw heads and attached to C1 screws or lateral mass screws below C2 (Fig. 23-58 and Table 23-32).53,174 
Figure 23-56
C2 translaminar screw placement (see text).
 
(From Leonard Jr, Wright NM. Pediatric atlantoaxial fixation with bilateral, crossing C2 translaminar screws. Technical note. J Neurosurg Pediatr. 2006; 104:59–63, with permission)
(From 


Leonard Jr, 
Wright NM
.
Pediatric atlantoaxial fixation with bilateral, crossing C2 translaminar screws. Technical note.
J Neurosurg Pediatr.
2006;
104:59–63, with permission)
View Original | Slide (.ppt)
Figure 23-56
C2 translaminar screw placement (see text).
(From Leonard Jr, Wright NM. Pediatric atlantoaxial fixation with bilateral, crossing C2 translaminar screws. Technical note. J Neurosurg Pediatr. 2006; 104:59–63, with permission)
(From 


Leonard Jr, 
Wright NM
.
Pediatric atlantoaxial fixation with bilateral, crossing C2 translaminar screws. Technical note.
J Neurosurg Pediatr.
2006;
104:59–63, with permission)
View Original | Slide (.ppt)
X
Flynn-ch023-image057.png
View Original | Slide (.ppt)
Figure 23-57
CT shows placement of screws.
Flynn-ch023-image057.png
View Original | Slide (.ppt)
X
Figure 23-58
Lateral (left) and anteroposterior (right) views of completed C1 to C2 fixation with C1 lateral mass screws connected to C2 laminar screws (lateral view).
 
(From Leonard JR, Wright NM. Pediatric atlantoaxial fixation with bilateral, crossing C2 translaminar screws. Technical note. J Neurosurg Pediatr. 2006; 104:59–63, with permission.)
(From 


Leonard JR,

Wright NM
.
Pediatric atlantoaxial fixation with bilateral, crossing C2 translaminar screws. Technical note.
J Neurosurg Pediatr.
2006;
104:59–63, with permission.)
View Original | Slide (.ppt)
Figure 23-58
Lateral (left) and anteroposterior (right) views of completed C1 to C2 fixation with C1 lateral mass screws connected to C2 laminar screws (lateral view).
(From Leonard JR, Wright NM. Pediatric atlantoaxial fixation with bilateral, crossing C2 translaminar screws. Technical note. J Neurosurg Pediatr. 2006; 104:59–63, with permission.)
(From 


Leonard JR,

Wright NM
.
Pediatric atlantoaxial fixation with bilateral, crossing C2 translaminar screws. Technical note.
J Neurosurg Pediatr.
2006;
104:59–63, with permission.)
View Original | Slide (.ppt)
X
 
Table 23-32
Crossed Translaminar Screw Fixation of C2
View Large
Table 23-32
Crossed Translaminar Screw Fixation of C2
Surgical Steps
  •  
    Open a small cortical window at C2 spinous process and lamina on left
  •  
    Drill right lamina and insert a 4-mm polyaxial screw
  •  
    Make a small cortical window at junction of spinous and lamina of C2 on right
  •  
    Drill left lamina and insert a 4-mm polyaxial screw
  •  
    Place rods into screw heads and attach to C1 screws or lateral mass screws
X
Potential Pitfalls and Preventative Measures
See p. 860 for potential pitfalls with posterior approaches. 

Anterior Arthrodesis

In older pediatric patients and adolescents, adult anterior instrumentation and fusion techniques may be used. Anatomy of the vertebral body should be evaluated preoperatively to determine if anterior plates and screws may be used.22 

Author's Preferred Treatment for Cervical Spine Injury

Occipital Condyle Fracture

Most occipital condyle fractures can be treated nonoperatively with an orthosis. A rigid occipital mandibular orthosis or cervical collar is the preferred method of immobilization. In the rare case that surgical stabilization is needed (type III), fusion from the occiput to C2 with a Luque rod and wire instrumentation or an occipital plate with screw fixation are recommended. 

Atlantooccipital Instability

Atlantooccipital dislocation is an unstable ligamentous injury. The author recommends operative treatment in the vast majority of patients. Fusion with instrumentation of the occiput to C2 is the preferred treatment. Instrumentation will depend on the size of the patient and the anatomy of the upper cervical spine. In small children in whom placement of screws will be difficult, contoured Luque rods and cables will give adequate stabilization. This provides immediate stabilization, and the patient can be mobilized in a cervical collar. If the patient's anatomy allows, an occipital plate and C1 and C2 screw fixation can be used; this rod and screw fixation provides more secure fixation than Luque rods and cables. These injuries usually are in younger patients, and screw and plate instrumentation may not be possible. Instrumentation to C2 is preferred over ending instrumentation at C1. There are usually significant soft tissue injuries and associated injuries. Extending the fusion and instrumentation to C2 gives better fixation and more surface area for fusion but is at the expense of increased loss of motion of the upper cervical spine postoperatively. 

Fractures of the Atlas

Most pediatric patient with an atlas fracture may be treated nonoperatively. Minimally displaced fractures or greenstick type fractures through the synchondrosis often can be treated in a rigid collar. If there is significant displacement on plain radiographs (>7 mm overhand) or on CT scan, then a short period of traction followed by halo immobilization is recommended. 

Odontoid Fracture

Most odontoid fractures can be treated nonoperatively in an extension Minerva cast or halo cast or brace. If the patient cannot be managed nonoperatively, then a C1 to C2 fusion is the authors' preferred method. In older children, the Harms C1, C2 instrumentation is used. If the anatomy does not allow for screw fixation, then a Brooks-type fusion is performed, and patient is immobilized in a halo. 

Atlantoaxial Instability

Atlantoaxial instability from rupture of the transverse ligament is rare in children. 
When an avulsion fracture of the transverse ligament occurs and is nondisplaced, nonoperative treatment may be considered in this special situation. Most injuries to the transverse ligament are unstable. The authors' preferred method of stabilization is with the Harms C1, C2 screw and rod technique and posterior fusion. Transarticular screw fixation is another acceptable stabilization method but is more difficult in a small child because of anatomical consideration. If the anatomy does not allow for safe placement of screws, then Brooks instrumentation and fusion are recommended. This will require halo or Minerva cast immobilization postoperatively. 

Subaxial Injuries

Most subaxial injuries occur in older children and adult instrumentation and fusion techniques are appropriate. In unstable subaxial injuries, such as facet fracture dislocations, lateral mass screw and rod fixation usually can be performed in children. Anterior instrumentation and fusion may need to be performed in burst type fractures or fracture-dislocation with disc herniation. 

References

1.
Abou Madawi A, Solanki G, Casey AT, et al. Variation of the groove in the axis vertebra for the vertebral artery. Implications for instrumentation. J Bone Joint Surg Br. 1997; 79:820–823.
2.
Adlegais KM, Grossman DC, Langer SC, et al. Use of helical computed tomography for imaging the pediatric cervical spine. Acad Emerg Med. 2004; 11:228–236.
3.
Allington JJ, Zembo M, Nadell J, et al. C1–C2 posterior soft tissue injuries with neurologic impairment in children. J Pediatr Orthop. 1990; 10:596–601.
4.
American Academy of Orthopaedic Surgeons, Committee on Pediatric Orthopaedics. Trauma of the Cervical Spine. Position Statement. Rosemont, IL: Author; 1990.
5.
American Academy of Pediatrics. Committee on Sports Medicine. Atlantoaxial instability in Down syndrome. Pediatrics. 1984; 74:152–154.
6.
American Academy of Pediatrics Committee on Sports Medicine and Fitness. Atlantoaxial instability in Down syndrome: subject review. Pediatrics. 1995; 96(1 Pt 1):151–154.
7.
Anderson JM, Schutt AH. Spinal injury in children: A review of 156 cases seen from 1950 through 1978. Mayo Clin Proc. 1980; 55:499–504.
8.
Anderson LD, D'Alonzo RT. Fractures of the odontoid process of the axis. J Bone Joint Surg Am. 1974; 56(8):1663–1674.
9.
Anderson LD, Smith BL Jr, DeTorre J, et al. The role of polytomography in the diagnosis and treatment of cervical spine injuries. Clin Orthop Relat Res. 1982; 165:64–68.
10.
Anderson PA, Montesano PX. Morphology and treatment of occipital condyle fractures. Spine. 1988; 13:731–736.
11.
Annis JA, Finlay DB, Allen MJ, et al. A review of cervical-spine radiographs in casualty patients. Br J Radiol. 1987; 60:1059–1061.
12.
Apple JS, Kirks DR, Merten DF, et al. Cervical spine fractures and dislocations in children. Pediatr Radiol. 1987; 17:45–49.
13.
Arlet V, Aebi M. Anterior and posterior cervical spine fusion and instrumentation. In: Weinstein SL, ed. Pediatric Spine Surgery. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2001:209–226.
14.
Arvin B, Fournier-Gosselin MP, Fehlings MG. Os odontoideum: etiology and surgical management. Neurosurgery. 2010; 66(3):22–31.
15.
Astur N, Klimo P Jr, Sawyer JR, et al. Traumatic atlanto-occipital dislocation in children: Evaluation, treatment and outcomes. J Bone Joint Surg. 2013; 95(A):e194(1–8).
16.
Aufdermaur M. Spinal injuries in juveniles: Necropsy findings in 12 cases. J Bone Joint Surg Br. 1974; 56:513–519.
17.
Aulino JM, Tutt LK, Kaye JJ, et al. Occipital condyle fractures: Clinical presentation and imaging findings in 76 patients. Emerg Radiol. 2005; 11:342–347.
18.
AuYong N, Piatt J Jr. Jefferson fractures of the immature spine. Report of 3 cases. J Neurosurg Pediatr. 2009; 3:15–19.
19.
Bachulis BL, Long WB, Hynes GD, et al. Clinical indications for cervical spine radiographs in the traumatized patient. Am J Surg. 1987; 153:473–477.
20.
Bailey DK. Normal cervical spine in infants and children. Radiology. 1952; 59:713–714.
21.
Banniza von Bazan UK, Paeslack V. Scoliotic growth in children with acquired paraplegia. Paraplegia. 1977; 15:65–73.
22.
Baron EM, Loftus CM, Vaccaro AR, et al. Anterior approach to the subaxial cervical spine in children: A brief review. Neurosurg Focus. 2006; 20:E4.
23.
Baum JA, Hanley EN Jr, Pullekines J. Comparison of halo complications in adults and children. Spine. 1989; 14:251–252.
24.
Bayar MA, Erdem Y, Ozturk K, et al. Isolated anterior arch fracture of the atlas: Child case report. Spine. 2002; 27:E47–E49.
25.
Bedbrook GM. Correction of scoliosis due to paraplegia sustained in pediatric age group. Paraplegia. 1977; 15:90–96.
26.
Benzel EC, Zhang DH, Iannotti C, et al. Occipitocervical fusion in an infant with atlantooccipital dislocation. World Neurosurg www.worldneurosurgery.org, 2012.
27.
Bernini EP, Elefante R, Smaltino F, et al. Angiographic study on the vertebral artery in cases of deformities of the occipitocervical joint. AJR Am J Roentgenol. 1969; 107:526–529.
28.
Birney TJ, Hanley EN Jr. Traumatic cervical spine injuries in childhood and adolescence. Spine. 1989; 14:1277–1282.
29.
Bivins HG, Ford S, Bezmalnovic Z, et al. The effect of axial traction during orotracheal intubation of the trauma victim with an unstable cervical spine. Ann Emerg Med. 1988; 17:25–29.
30.
Bohlman HH. Acute fractures and dislocations of the cervical spine. J Bone Joint Surg Am. 1969; 61:1119–1142.
31.
Bohn D, Armstrong D, Becker L, et al. Cervical spine injuries in children. J Trauma. 1990; 30:463–469.
32.
Booth TN. Cervical spine evaluation in pediatric trauma. Am J Radiol. 2012; 198:W417–W425.
33.
Bracken MB. Treatment of acute spinal cord injury with methylprednisolone: Results of a multicenter randomized clinical trial. J Neurotrauma. 1991; 8(Suppl 1):47–50.
34.
Bracken MB. Pharmacological treatment of acute spinal cord injury: current status and future projects. J Emerg Med. 1993; 11(Suppl 1):43–48.
35.
Bracken MB, Shepard MJ, Collins WF Jr, et al. A randomized controlled trial of methylprednisolone or naloxone in the treatment of acute spinal cord injury: Results of the Second National Spinal Cord Injury Study. N Engl J Med. 1990; 322:1405–1411.
36.
Bracken MB, Shepard MJ, Collins WF Jr, et al. Methylprednisolone or naloxone treatment after acute spinal cord injury: 1-year follow-up data. Results of the Second National Acute Spinal Cord Injury Study. J Neurosurg. 1992; 76:23–31.
37.
Brecknell JE, Malham GM. Os odontoideum: Report of three cases. J Clin Neurosci. 2008; 15:295–301.
38.
Bresnan MJ, Abroms IF. Neonatal spinal cord transection secondary to intrauterine hyperextension of neck in breech presentation. J Pediatr. 1974; 84:734–737.
39.
Brockmeyer DL, Apfelbaum RI. A new occipitocervical fusion construct in pediatric patients with occipitocervical instability. Technical note. J Neurosurg. 1999; 90(Suppl 2):271–275.
40.
Brockmeyer DL, Ragel BT, Kestle JR. The pediatric cervical spine instability study. A pilot study assessing the prognostic value of four imaging modalities in clearing the cervical spine for children with severe traumatic injuries. Childs Nerv Syst. 2012; 28:699–705.
41.
Brockmeyer DL, York JE, Apfelbaum RI. Anatomic suitability of C1–C2 transarticular screw placement in pediatric patients. J Neurosurg. 2000; 92(Suppl 1):7–11.
42.
Brooks AL, Jenkins EB. Atlantoaxial arthrodesis by the wedge compression method. J Bone Joint Surg Am. 1978; 60:279–290.
43.
Bucholz RW, Burkhead WZ. The pathological anatomy of fatal atlanto-occipital dislocations. J Bone Joint Surg Am. 1979; 61:248–250.
44.
Bulas DI, Fitz CR, Johnson DL. Traumatic atlanto-occipital dislocation in children. Radiology. 1993; 188:155–158.
45.
Bundschuh CV, Alley JB, Ross M, et al. Magnetic resonance imaging of suspected atlanto-occipital dislocation. Spine. 1992; 17:245–248.
46.
Burke DC. Spinal cord trauma in children. Paraplegia. 1971; 9:1–14.
47.
Burke DC. Traumatic spinal paralysis in children. Paraplegia. 1971; 9:268–276.
48.
Burke SW, French HG, Roberts JM, et al. Chronic atlanto-axial instability in Down syndrome. J Bone Joint Surg Am. 1985; 67:1356–1360.
49.
Burkus JK, Deponte RJ. Chronic atlantoaxial rotatory fixation: correction by cervical traction, manipulation, and branching. J Pediatr Orthop. 1986; 6:631–635.
50.
Caffey J. The whiplash shaken infant syndrome. Pediatrics. 1974; 54:396–403.
51.
Capuano C, Costagliola C, Shamsaldin M, et al. Occipital condyle fractures: A hidden nosological entity. An experience with 10 cases. Acta Neurochir (Wien). 2004; 146: 779–784.
52.
Cattell HS, Filtzer DL. Pseudosubluxation and other normal variations in the cervical spine in children. J Bone Joint Surg Am. 1965; 47:1295–1309.
53.
Chamoun RB, Relyea KM, Johnson KK, et al. Use of axial and subaxial translaminar screw fixation in the management of upper cervical spinal instability in a series of 7 children. Neurosurgery. 2009; 64(4):734–739.
54.
Chen JY, Soares G, Lambiase R, et al. A previously unrecognized connection between occipital condyle fractures and internal carotid injuries. Emerg Radiol. 2006; 12(4):192–195.
55.
Chern JJ, Chamoun RB, Whitehead WE, et al. Computed tomography morphometric analysis for axial and subaxial translaminar screw placement in the pediatric cervical spine. J Neurosurg Pediatr. 2009; 3:121–128.
56.
Chugh S, Kamian K, Depreitere B, et al. Occipital condyle fracture with associated hypoglossal nerve injury. Can J Neurol Sci. 2006; 33:322.
57.
Chung S, Mikrogianakis A, Wales PW, et al. Trauma Association of Canada Pediatric Subcommittee National Pediatric Cervical Spine Evaluation Pathway: Consensus guidelines. J Trauma. 2011; 70:873–884.
58.
Collalto PM, DeMuth WW, Schwentker EP, et al. Traumatic atlanto-occipital dislocation. J Bone Joint Surg Am. 1986; 68:1106–1109.
59.
Conry BG, Hall CM. Cervical spine fractures and rear car seat restraints. Arch Dis Child. 1987; 62:1267–1268.
60.
Copley LA, Dormans JP. Cervical spine disorders in infants and children. J Am Acad Orthop Surg. 1998; 6:204–214.
61.
Copley LA, Dormans JP, Pepe MD, et al. Accuracy and reliability of torque wrenches used for halo application in children. J Bone Joint Surg Am. 2003; 85:2199–2204.
62.
Copley LA, Pepe MD, Tan V, et al. A comparison of various angles of halo pin insertion in an immature skull model. Spine. 1999; 24:1777–1780.
63.
Curran C, Dietrich AM, Bowman MJ, et al. Pediatric cervical-spine immobilization: achieving neutral position? J Trauma. 1995; 39:729–732.
64.
Davidson RG. Atlantoaxial instability in individuals with Down syndrome: A fresh look at the evidence. Pediatrics. 1988; 81:857–865.
65.
Dawson EG, Smith L. Atlanto-axial subluxation in children due to vertebral anomalies. J Bone Joint Surg Am. 1979; 61:582–587.
66.
de Beer JD, Hoffman EB, Kieck CF. Traumatic atlantoaxial subluxation in children. J Pediatr Orthop. 1990; 10:397–400.
67.
DiBenedetto T, Lee CK. Traumatic atlanto-occipital instability: a case report with follow-up and a new diagnostic technique. Spine. 1990; 15:595–597.
68.
Dickman CA, Greene KA, Sonntag UK. Injuries involving the transverse atlantal ligament: classification and treatment guidelines based on experience with 39 injuries. Neurosurgery. 1996; 38:44–50.
69.
Dietrich AM, Ginn-Pease ME, Bartkowski HM, et al. Pediatric cervical spine fractures: Predominately subtle presentation. J Pediatr Surg. 1991; 26:995–1000.
70.
Donahue D, Maulbauer MS, Kaufman RA, et al. Childhood survival of atlanto-occipital dislocation: underdiagnosis, recognition, treatment, and review of the literature. Pediatr Neurosurg. 1994; 21:105–111.
71.
Dormans JP, Criscitiello AA, Drummond DS, et al. Complications in children managed with immobilization in a halo vest. J Bone Joint Surg Am. 1995; 77:1370–1373.
72.
Dormans JP, Drummond DS, Sutton LN, et al. Occipitocervical arthrodesis in children. J Bone Joint Surg Am. 1995; 77:1234–1240.
73.
Dvorak J, Panjabi M, Gerber M, et al. CT-functional diagnostics of the rotatory instability of the cervical spine: 1. An experimental study on cadavers. Spine. 1987; 12: 197–205.
74.
Dyck P. Os odontoideum in children: neurological manifestations and surgical management. Neurosurgery. 1978; 2:93–99.
75.
Easter JS, Barkin R, Rosen CL, et al. Cervical spine injuries in children, part I: Mechanism of injury, clinical presentation, and imaging. J Emerg Med. 2011; 41:142–150.
76.
Easter JS, Barkin R, Rosen CL, et al. Cervical spine injuries in children, part II: Management and special considerations. J Emerg Med. 2011; 41(3):252–256.
77.
Effendi B, Roy D, Cornish B, et al. Fracture of the rung of the axis. A classification based on the analysis of 131 cases. J Bone Joint Surg Br. 1981; 63:319–327.
78.
Ehlinger M, Charles Y-P, Adam P, et al. Survivor of a traumatic atlanto-occipital dislocation. Orthop Traumatol Surg Res. 2011; 97:335–340.
79.
Eleraky MA, Theodore N, Adams M, et al. Pediatric cervical spine injuries: report of 102 cases and review of the literature. J Neurosurg. 2000; 92(Suppl 1):12–17.
80.
El-Khoury GY, Kathol MH. Radiographic evaluation of cervical trauma. Semin Spine Surg. 1991; 3:3–23.
81.
Evans DL, Bethem D. Cervical spine injuries in children. J Pediatr Orthop. 1989; 9:563–568.
82.
Evarts CM. Traumatic occipito-atlanto dislocation. J Bone Joint Surg Am. 1970; 52:1653–1660.
83.
Fardon DF, Fielding JW. Defects of the pedicle and spondylolisthesis of the second cervical vertebra. J Bone Joint Surg Br. 1981; 63:526–528.
84.
Farley FA, Graziano GP, Hensinger RN. Traumatic atlanto-occipital dislocation in a child. Spine. 1992; 17:1539–1541.
85.
Farley FA, Hensinger RN, Herzenberg JE. Cervical spinal cord injury in children. J Spinal Disord. 1992; 5:410–416.
86.
Ferri-de-Barros F, Little DG, Bridge C, et al. Atlantoaxial and craniocervical arthrodesis in children. A tomographic study comparing suitability of C2 pedicles and C2 laminae for screw fixation. Spine. 2010; 35(3)291–293.
87.
Fielding JW. Cineroentgenography of the normal cervical spine. J Bone Joint Surg Am. 1957; 39:1280–1288.
88.
Fielding JW, Griffin PP. Os odontoideum: an acquired lesion. J Bone Joint Surg Am. 1974; 56:187–190.
89.
Fielding JW, Hawkins RJ. Atlanto-axial rotary fixation (fixed rotary subluxation of the atlanto-axial joint). J Bone Joint Surg Am. 1977; 59:37–44.
90.
Fielding JW, Hensinger RN, Hawkins RJ. Os odontoideum. J Bone Joint Surg Am. 1980; 62:376–383.
91.
Fielding JW, Stillwell WT, Chynn KY, et al. Use of computed tomography for the diagnosis of atlanto-axial rotatory fixation. A case report. J Bone Joint Surg Am. 1978; 60:1102–1104.
92.
Finch GD, Barnes MJ. Major cervical spine injuries in children and adolescents. J Pediatr Orthop. 1998; 18:811–814.
93.
Flynn JM, Closkey RF, Mahboubi S, et al. Role of magnetic resonance imaging in the assessment of pediatric cervical spine injuries. J Pediatr Orthop. 2002; 22:573–577.
94.
Francis WR, Fielding JW, Hawkins RJ, et al. Traumatic spondylolisthesis of the axis. J Bone Joint Surg Br. 1981; 63:313–318.
95.
Fuchs S, Barthel MJ, Flannery AM, et al. Cervical spine fractures sustained by young children in forward-facing car seats. Pediatrics. 1989; 84:348–354.
96.
Gallie WE. Fractures and dislocations of the cervical spine. Am J Surg. 1939; 46:495–499.
97.
Garfin SR, Roux R, Botte MJ, et al. Skull osteology as it affects halo pin placement in children. J Pediatr Orthop. 1986; 6:434–436.
98.
Geehr RB, Rothman SLG, Kier EL. The role of computed tomography in the evaluation of upper cervical spine pathology. Comput Tomogr. 1978; 2:79–97.
99.
Geisler FH, Dorsey FC, Coleman WP. GM-1 ganglioside in human spinal cord injury. J Neurotrauma. 1992; 9(Suppl 1):407–416.
100.
Geisler FH, Dorsey FC, Coleman WP. Past and current clinical studies with GM-1 ganglioside in acute spinal cord injury. Rev Ann Emerg Med. 1993; 22:1041–1047.
101.
Geisler FH, Dorsey FC, Coleman WP. Recovery of motor function after spinal cord injury—a randomized, placebo-controlled trial with GM-1 ganglioside. N Engl J Med. 1991; 324:1829–1838.
102.
Geisler FH, Dorsey FC, Coleman WP. Recovery of motor function after spinal cord injury—a randomized, placebo-controlled trial with GM-1 ganglioside [erratum]. N Engl J Med. 1991; 325:1669–1670.
103.
Georgopoulos G, Pizzutillo PD, Lee MS. Occipito-atlanto instability in children. A report of five cases and review of the literature. J Bone Joint Surg Am. 1987; 69:429–436.
104.
Gerling MC, Davis DP, Hamilton RS, et al. Effects of cervical spine immobilization technique and laryngoscope blade selection on an unstable cervical spine in a cadaver model of intubation. Ann Emerg Med. 2000; 36:279–300.
105.
Ghanem I, El Hage S, Rachkidi R, et al. Pediatric cervical spine instability. J Child Orthop. 2008; 2:71–84.
106.
Ghatan S, Ellenbogen RG. Pediatric spine and spinal cord injury after inflicted trauma. Neurosurg Clin North Am. 2002; 13:227–233.
107.
Giannestras NJ, Mayfield FH, Maurer J. Congenital absence of the odontoid process. J Bone Joint Surg Am. 1964; 46:839–843.
108.
Givens T, Polley KA, Smith GF, et al. Pediatric cervical spine injury: a 3-year experience. J Trauma. 1996; 41:310–314.
109.
Gluf WM, Brockmeyer DL: Atlantoaxial transarticular screw fixation: a review of surgical indications, fusion rate, complications, and lessons learned in 67 pediatric patients. J Neurosurg Spine. 2005; 2:164–169.
110.
Godard J, Hadji M, Raul JS. Odontoid fractures in the child with neurologic injury. Direct osteosynthesis with a cortico-spongious screw and literature review. Childs Nerv Syst. 1997; 13:105–107.
111.
Grantham SA, Dick HM, Thompson RC, et al. Occipitocervical arthrodesis: Indications, technique, and results. Clin Orthop Relat Res. 1969; 65:118–129.
112.
Griffiths SC. Fracture of the odontoid process in children. J Pediatr Surg. 1972; 7:680–683.
113.
Gupta R, Bathen ME, Smith JS, et al. Advances in the management of spinal cord injury. J Am Acad Orthop Surg. 2010; 18(4):210–222.
114.
Hadley MN. Occipital condyle fractures. Neurosurgery. 2002; 50(Suppl):S114–S119.
115.
Hadley MN, Zabramski JM, Browner CM, et al. Pediatric spinal trauma: Review of 122 cases of spinal cord vertebral column injuries. J Neurosurg. 1988; 68:18–24.
116.
Haffner DL, Hoffer MM, Wiedebusch R. Etiology of children's spinal injuries at Rancho Los Amigos. Spine. 1993; 18:679–684.
117.
Hall JE, Denis F, Murray J. Exposure of the upper cervical spine for spinal decompression by a mandible and tongue-splitting approach. Case report. J Bone Joint Surg Am. 1977; 59:121–125.
118.
Hall JE, Simmons ED, Danylchuk K, et al. Instability of the cervical spine and neurological involvement in Klippel-Feil syndrome: A case report. J Bone Joint Surg Am. 1990; 72:460.
119.
Hamilton MG, Myles ST. Pediatric spinal injury. Review of 61 deaths. J Neurosurg. 1988; 77:705–708.
120.
Hammerschlag W, Ziv I, Wald U, et al. Cervical instability in an achondroplastic infant. J Pediatr Orthop. 1988; 8:481–484.
121.
Hanson JA, Deliganis AV, Baxter AB, et al. Radiologic and clinical spectrum of occipital condyle fractures: retrospective review of 107 consecutive fractures in 95 patients. AJR Am J Roentgenol. 2002; 178:1261–1268.
122.
Haque A, Price AV, Sklar FH, et al. Screw fixation of the upper cervical spine in the pediatric population. J Neurosurg Pediatr. 2009; 3:529–533.
123.
Harmanli O, Kaufman Y. Traumatic atlanto-occipital dislocation with survival. Surg Neurol. 1993; 39:324–330.
124.
Harms J, Melcher RP. Posterior C1–C2 fusion with polyaxial screw and rod fixation. Spine. 2001; 26:2467–2471.
125.
Harris JH Jr, Carson GC, Wagner LK, et al. Radiologic diagnosis of traumatic occipitovertebral dissociation: 2. Comparison of three methods of detecting occipitovertebral relationships on lateral radiographs of supine subjects. AJR Am J Roentgenol. 1994; 162:887–892.
126.
Harris MB, Duval MJ, Davis JA Jr, et al. Anatomical and roentgenographic features of atlantooccipital instability. J Spinal Disord. 1993; 6:5–10.
127.
Hawkins RJ, Fielding JW, Thompson WJ. Os odontoideum: congenital or acquired. J Bone Joint Surg Am. 1976; 58:413.
128.
Hedequist D, Hresko T, Proctor M. Modern cervical spine instrumentation in children. Spine. 2008; 33:379–383.
129.
Hedequist DJ, Emans JB. The correlation of preoperative three-dimensional computed tomography reconstructions with operative findings in congenital scoliosis. Spine. 2003; 28:2531–2534.
130.
Heller JG, Jeffords P. Internal fixation of the cervical spine. C. Posterior instrumentation of the lower cervical spine. In: Frymoyer JW, Wiesel SW, eds. The Adult and Pediatric Spine. Philadelphia, PA: Lippincott Williams & Wilkins; 2004:803–816.
131.
Henriques T, Cunningham BW, Olerud C, et al. Biomechanical comparison of five different atlantoaxial posterior fixation techniques. Spine. 2000; 25:2877–2883.
132.
Hensinger RN, DeVito PD, Ragsdale CG. Changes in the cervical spine in juvenile rheumatoid arthritis. J Bone Joint Surg Am. 1986; 68:189–198.
133.
Hensinger RN, Fielding JW, Hawkins RJ. Congenital anomalies of the odontoid process. Orthop Clin North Am. 1978; 9:901–912.
134.
Hensinger RN, Lang JE, MacEwen GD. Klippel-Feil syndrome: A constellation of associated anomalies. J Bone Joint Surg Am. 1974; 56:1246–1252.
135.
Herzenberg JE, Hensinger RN. Pediatric cervical spine injuries. Trauma Q. 1989; 5:73–81.
136.
Herzenberg JE, Hensinger RN, Dedrick DK, et al. Emergency transport and positioning of young children who have an injury of the cervical spine: The standard backboard may be hazardous. J Bone Joint Surg Am. 1989; 71:15–22.
137.
Hohl M, Baker HR. The atlanto-axial joint: Roentgenographic and anatomical study of normal and abnormal motion. J Bone Joint Surg Am. 1964; 46:1739–1752.
138.
Hosono N, Yonenobu K, Kawagoe K, et al. Traumatic anterior atlanto-occipital dislocation. Spine. 1993; 18:786–790.
139.
Howard AW, Letts RM. Cervical spondylolysis in children: Is it posttraumatic? J Pediatr Orthop. 2000; 20:677–681.
140.
Hoy GA, Cole WG. The paediatric cervical seat belt syndrome. Injury. 1993; 24:297–299.
141.
Hubbard DD. Injuries of the spine in children and adolescents. Clin Orthop Relat Res. 1974; 100:56–65.
142.
Huerta C, Griffith R, Joyce SM. Cervical spine stabilization in pediatric patients. Evaluation of current techniques. Ann Emerg Med. 1987; 16:1121–1126.
143.
Hukda S, Ota H, Okabe N, et al. Traumatic atlantoaxial dislocation causing os odontoideum in infants. Spine. 1980; 5:207–210.
144.
Ishii K, Chiba K, Maruiwa H, et al. Pathognomonic radiological signs for predicting prognosis in patients with chronic atlantoaxial rotatory fixation. J Neurosurg Spine. 2006; 5:385–391.
145.
Ishikawa M, Matsumoto M, Chiba K, et al. Long-term impact of atlantoaxial arthrodesis on the pediatric cervical spine. J Orthop Sci. 2009; 14:274–278.
146.
Jea A, Johnson KK, Whitehead WE, et al. Translaminar screw fixation in the subaxial pediatric cervical spine. J Neurosurg Pediatr. 2008; 2:386–390.
147.
Jefferson G. Fracture of the atlas vertebra: Report of four cases and a review of those previously recorded. Br J Surg. 1920; 7:407–422.
148.
Jones ET, Hensinger RN. Cervical spine injuries in children. Contemp Orthop. 1982; 5:17–23.
149.
Jones TM, Anderson PA, Noonan KJ. Pediatric cervical spine trauma. J Am Acad Orthop Surg. 2011; 19:600–611.
150.
Judd DB, Liem LK, Petermann G. Pediatric atlas fracture: A case of fracture through a synchondrosis and review of the literature. Neurosurgery. 2000; 46:991–995.
151.
Junewick JJ. Pediatric craniocervical junction injuries. Am J Radiol. 2011; 196:1003–1010.
152.
Karam YR, Traynelis VC. Occipital condyle fractures. Neurosurgery. 2010; 33:322–324.
153.
Kaufman RA, Carroll CD, Buncher CR. Atlanto-occipital junction: Standards for measurement in normal children. AJNR Am J Neuroradiol. 1987; 8:995–999.
154.
Kawabe N, Hirotoni H, Tanaka O. Pathomechanism of atlanto-axial rotatory fixation in children. J Pediatr Orthop. 1989; 9:569–574.
155.
Keenan HT, Hollingshead MC, Chung CJ, et al. Using CT of the cervical spine for early evaluation of pediatric patients with head trauma. AJR Am J Roentgenol. 2001; 177:1405–1409.
156.
Kenter K, Worley G, Griffin T, et al. Pediatric traumatic atlanto-occipital dislocation: Five cases and a review. J Pediatr Orthop. 2001; 21:585–589.
157.
Kewalramani LS, Kraus JF, Sterling HM. Acute spinal-cord lesions in a pediatric population: Epidemiological and clinical features. Paraplegia. 1980; 18:206–219.
158.
Kilfoyle RM, Foley JJ, Norton PL. Spine and pelvic deformity in childhood and adolescent paraplegia. J Bone Joint Surg Am. 1965; 47:659–682.
159.
Kleinman PK, Shelton YA. Hangman's fracture in an abused infant: Imaging. Pediatr Radiol. 1997; 27:776–777.
160.
Klippel M, Feil A. Anomalies de la collone vertebrale par absence des vertebres cervicales; avec cage thoraque remontant jusqu'ala bas du crane. Bull Soc Anat Paris. 1912; 87:185.
161.
Kobori M, Takahashi H, Mikawa Y. Atlanto-axial dislocation in Down syndrome: Report of two cases requiring surgical correction. Spine. 1986; 11:195–200.
162.
Kokoska ER, Keller MS, Rallo MC, et al. Characteristics of pediatric cervical spine injuries. J Pediatr Surg. 2001; 36:100–105.
163.
Koop SE, Winter RB, Lonstein JE. The surgical treatment of instability of the upper part of the cervical spine in children and adolescents. J Bone Joint Surg Am. 1984; 66:403–411.
164.
Kopelman TR, Berardon NE, O'Neill PJ, et al. Risk factors for blunt cerebrovascular injury in children: Do they mimic those seen in adults? J Trauma. 2011; 71:559–564.
165.
Korinth MC, Kapser A, Weinzierl MR. Jefferson fracture in a child—illustrative case report. Pediatr Neurosurg. 2007; 43:526–530.
166.
Kransdorf MJ, Wherle PA, Moser RP Jr. Atlantoaxial subluxation in Reiter syndrome. Spine. 1988; 13:12–14.
167.
Kuhns LR, Loder RT, Farley FA, et al. Nuchal cord changes in children with os odontoideum: Evidence for associated trauma. J Pediatr Orthop. 1998; 18:815–819.
168.
Kuhns LR, Strouse PJ. Cervical spine standards for flexion radiograph interspinous distance ratios in children. Acta Radiol. 2000; 7:615–619.
169.
Lally KP, Senac M, Hardin WD Jr, et al. Utility of the cervical spine radiograph in pediatric trauma. Am J Surg. 1989; 158:540–542.
170.
Lawson JP, Ogden JA, Bucholz RW, et al. Physeal injuries of the cervical spine. J Pediatr Orthop. 1987; 7:428–435.
171.
Lebwohl NH, Eismont FJ. Cervical spine injuries in children. In: Weinstein SL, ed. The Pediatric Spine: Principles and Practice. Philadelphia, PA: Lippincott Williams & Wilkins; 2001:553–566.
172.
Lennarson PJ, Smith D, Todd MM, et al. Segmental cervical spine motion during orotracheal intubation of the intact and injured spine with and without external stabilization. J Neurosurg. 2000; 92:201–206.
173.
Leonard JC, Kuppermann N, Olsen C, et al. Factors associated with cervical spine injury in children after blunt trauma. Ann Emerg Med. 2011; 58:145–155.
174.
Leonard JR, Wright NM. Pediatric atlantoaxial fixation with bilateral, crossing C2 translaminar screws. Technical note. J Neurosurg Pediatr. 2006; 104:59–63.
175.
Letts M, Kaylor D, Gouw G. A biomechanical study of halo fixation in children. J Bone Joint Surg Br. 1987; 70:277–279.
176.
Levine AM, Edwards CC. The management of traumatic spondylolisthesis of the axis. J Bone Joint Surg Am. 1985; 67:217–222.
177.
Liu JK, Decker D, Tenner MS, et al. Traumatic arteriovenous fistula of the posterior inferior cerebellar artery treated with endovascular coil embolization: Case report. Surg Neurol. 2004; 61(3):255–261.
178.
Lui TN, Lee ST, Wong CW, et al. C1–C2 fracture-dislocations in children and adolescents. J Trauma. 1996; 40:408–411.
179.
Lynch JM, Meza MP, Pollack IF, et al. Direct injury to the cervical spine of a child by a lap-shoulder belt resulting in quadriplegia: Case report. J Trauma. 1996; 41:747–749.
180.
Maekawa K, Masaki T, Kokubun Y. Fetal spinal cord injury secondary to hyperextension of the neck: No effect of caesarean section. Dev Med Child Neurol. 1976; 18:228–232.
181.
Magerl F, Seeman P. Stable posterior fusion of the atlas and axis by transarticular screw fixation. In: Kehr P, Weidner A, eds. Cervical Spine. Vienna: Springer-Verlag; 1985:322–327.
182.
Maheshwaran S, Sgouros S, Jeyapalan K, et al. Imaging of childhood torticollis due to atlanto-axial rotatory fixation. Childs Nerv Syst. 1995; 11:667–671.
183.
Majernick TG, Bieniek R, Houston JB, et al. Cervical spine movement during orotracheal intubation. Ann Emerg Med. 1986; 15:417–420.
184.
Mannix R, Nigrovic LE, Schutzman SA, et al. Factors associated with the use of cervical spine computed tomography imaging in pediatric trauma patients. Acad Emerg Med. 2011; 18:906–911.
185.
Manson NA, An HS: Halo placement in the pediatric and adult patient. In: Vaccaro AR, Barton EM, eds Operative Techniques in Spine Surgery. Philadelphia, PA: Saunders; 2008:13.
186.
Marlin AE, Gayle RW, Lee JF. Jefferson fractures in children. J Neurosurg. 1983; 58:277–279.
187.
Matthews LS, Vetter LW, Tolo VT. Cervical anomaly stimulating hangman's fracture in a child. J Bone Joint Surg Am. 1982; 64:299–300.
188.
Mayfield JK, Erkkila JC, Winter RB. Spine deformities subsequent to acquired childhood spinal cord injury. Orthop Trans. 1979; 3:281–282.
189.
Mazur JM, Loveless EA, Cummings RJ. Combined odontoid and Jefferson fracture in a child: a case report. Spine. 2002; 27:E197–E199.
190.
McClain RF, Clark CR, El-Khoury GY. C6–C7 dislocation in a neurologically intact neonate: a case report. Spine. 1989; 14:125–126.
191.
McGrory BJ, Klassen RA, Chao EY, et al. Acute fracture and dislocations of the cervical spine in children and adolescents. J Bone Joint Surg Am. 1993; 75:988–995.
192.
McGuire KJ, Silber J, Flynn JM, et al. Torticollis in children: can dynamic computed tomography help determine severity and treatment? J Pediatr Orthop. 2002; 22:766–770.
193.
Menezes AH. Surgical approaches to the craniocervical junction. In: Weinstein SL, ed. Pediatric Spine Surgery. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2001:127–148.
194.
Menezes AH, Ryken JC. Craniovertebral junction abnormalities. In: Weinsten SL, ed. The Pediatric Spine: Principles and Practice. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2001:219–238.
195.
Mikawa Y, Watanabe R, Yamano Y, et al. Fractures through a synchondrosis of the anterior arch of the atlas. J Bone Joint Surg Br. 1987; 69:483.
196.
Millington PJ, Ellingsen JM, Hauswirth BE, et al. Thermoplastic Minerva body jacket—a practical alternative to current methods of cervical spine stabilization. Phys Ther. 1987; 67:223–225.
197.
Miz GS, Engler GL. Atlanto-axial subluxation in Larsen's syndrome: A case report. Spine. 1987; 12:411–412.
198.
Momjian S, Dehdashti AR, Kehrli P, et al. Occipital condyle fractures in children: Case report and review of the literature. Pediatr Neurosurg. 2003; 38:265–270.
199.
Mondschein J, Karasick D. Spondylolysis of the axis vertebra: A rare anomaly simulating hangman's fracture. AJR Am J Roentgenol. 1999; 172:556–557.
200.
Mortazavi M, Gore PA, Chang S, et al. Pediatric cervical spine injuries: A comprehensive review. Childs Nerv Syst. 2011; 27:705–717.
201.
Mortazavi MM, Dogan S, Civelek R, et al. Pediatric multilevel spine injuries: An institutional experience. Childs Nerv Syst. 2011; 27:1095–1100.
202.
Msall ME, Reese ME, DiGaudio K, et al. Symptomatic atlantoaxial instability associated with medial and rehabilitative procedures in children with Down syndrome. Pediatrics. 1990; 85:447–449.
203.
Mubarak SJ, Camp JF, Vuletich W, et al. Halo application in the infant. J Pediatr Orthop. 1989; 9:612–614.
204.
Müller EJ, Wick M, Muhr G. Traumatic spondylolisthesis of the axis: Treatment rationale based on the stability of the different fracture types. Eur Spine J. 2000; 9:123–128.
205.
Murphy MJ, Southwick WO. Posterior approaches and fusions. In: Cervical Spine Research Society. The Cervical Spine. Philadelphia, PA: JB Lippincott; 1983:506–507.
206.
Nannapaneni R, Nath FP, Papastefanou SL. Fracture of the clavicle associated with a rotatory atlantoaxial subluxation. Injury. 2001; 32:71–73.
207.
Nigrovic LE, Rogers AJ, Adelgais KM, et al. Utility of plain radiographs in detecting traumatic injuries of the cervical spine in children. Pediatr Emerg Care. 2012; 28:426–432.
208.
Nitecki S, Moir CR. Predictive factors of the outcome of traumatic cervical spine fracture in children. J Pediatr Surg. 1994; 29:1409–1411.
209.
Noble ER, Smoker WRK. The forgotten condyle: The appearance, morphology, and classification of occipital condyle fractures. AJNR Am J Neuroradiol. 1996; 17:507–513.
210.
Nordström RE, Lahrendanta TV, Kaitila II, et al. Familial spondylolisthesis of the axis is vertebra. J Bone Joint Surg Br. 1986; 68:704–706.
211.
Norman MG, Wedderburn LC. Fetal spinal cord injury with cephalic delivery. Obstet Gynecol. 1973; 42:355–358.
212.
Nuckley DJ, Van Nausdle JA, Eck MP, et al. Neural space and biomechanical integrity of the developing cervical spine in compression. Spine. 2007; 32:E181–E187.
213.
Nypaver M, Treloar D. Neutral cervical spine positioning in children. Ann Emerg Med. 1994; 23:208–211.
214.
Odent T, Langlais J, Glorion C, et al. Fractures of the odontoid process: A report of 15 cases in children younger than 6 years. J Pediatr Orthop. 1999; 19:51–54.
215.
Orenstein JB, Klein BL, Gotschall CS, et al. Age and outcome in pediatric cervical spine injury: 11-year experience. Pediatr Emerg Care. 1994; 10:132–137.
216.
Orenstein JB, Klein BL, Oschensclager DW. Delayed diagnosis of pediatric cervical spine injury. Pediatrics. 1992; 89:1185–1188.
217.
Pang D. Atlantoaxial rotatory fixation. Neurosurgery. 2010; 66(3):A161–A183.
218.
Pang D, Nemzek WR, Zovickian J. Atlanto-occipital dislocation—part 2: The clinical use of (occipital) condyle-C1 interval, comparison with other diagnostic methods, and the manifestation, management, and outcome of atlanto-occipital dislocation in children. Neurosurgery. 2007; 61:995–1015.
219.
Pang D, Pollack IF. Spinal cord injury without radiologic abnormality in children: The SCIWORA syndrome. J Trauma. 1989; 29:654–664.
220.
Pang D, Wilberger JE. Spinal cord injury without radiologic abnormalities in children. J Neurosurg. 1982; 57:114–129.
221.
Panjabi MM, White AA III, Johnson RM. Cervical spine mechanics as a function of transection of components. J Biomech. 1975; 8(5):327–336.
222.
Panjabi MM, White AA III, Keller D, et al. Stability of the cervical spine under tension. J Biomech. 1978; 11:189–197.
223.
Papadopoulos SM, Dickman CA, Sonntag VK, et al. Traumatic atlanto-occipital dislocation with survival. Neurosurgery. 1991; 28:574–579.
224.
Parbhoo AH, Govender S, Corr P. Vertebral artery injury in cervical spine trauma. Injury. 2001; 32:565–568.
225.
Parent S, Dimar J, Dekutoski M, et al. Unique features of pediatric spinal cord injury. Spine. 2010; 35(Suppl 21):S202–S208.
226.
Parent S, Mac-Thiong JM, Roy-Beaudry M, et al. Spinal cord injury in the pediatric population: A systematic review of the literature. J Neurotrauma. 2011; 28:1515–1524.
227.
Parisi M, Lieberson R, Shatsky S. Hangman's fracture or primary spondylolysis: A patient and a brief review. Pediatr Radiol. 1991; 21:367–368.
228.
Parke WW, Rothman RH, Brown MD. The pharyngovertebral veins: an anatomical rationale for Grisel syndrome. J Bone Joint Surg Am. 1984; 66:568–574.
229.
Patel JC, Dailey A, Brodke DS, et al. Subaxial cervical spine trauma classification: The Subaxial Injury Classification system and case examples. Neurosurg Focus. 2008; 25:E8.
230.
Patel JC, Tepas JJ 3rd, Mollitt DL, et al. Pediatric cervical spine injuries: defining the disease. J Pediatr Surg. 2001; 36:373–376.
231.
Pennecot GF, Gourard D, Hardy JR, et al. Roentgenographical study of the stability of the cervical spine in children. J Pediatr Orthop. 1984; 4:346–352.
232.
Phillips WA, Hensinger RN. The management of rotatory atlantoaxial subluxation in children. J Bone Joint Surg Am. 1989; 71:664–668.
233.
Pizzutillo PD, Herman MJ. Cervical spine issues in Down syndrome. J Pediatr Orthop. 2005; 25:253–259.
234.
Pizzutillo PD, Rocha EF, D'Astous J, et al. Bilateral fractures of the pedicle of the second cervical vertebra in the young child. J Bone Joint Surg Am. 1986; 68:892–896.
235.
Powers B, Miller MD, Kramer RS, et al. Traumatic anterior occipital dislocation. Neurosurgery. 1979; 4:12–17.
236.
Price E. Fractured odontoid process with anterior dislocation. J Bone Joint Surg Br. 1960; 42:410–413.
237.
Pueschel SM. Atlantoaxial subluxation in Down syndrome. Lancet. 1983; 1:980.
238.
Pueschel SM, Scolia FH. Atlantoaxial instability in individuals with Down syndrome: Epidemiologic, radiographic, and clinical studies. Pediatrics. 1987; 4:555–560.
239.
Rachesky I, Boyce WT, Duncan B, et al. Clinical prediction of cervical spine injuries in children: Radiographic abnormalities. Am J Dis Child. 1987; 141:199–201.
240.
Ralston ME, Chung K, Barnes PD, et al. Role of flexion-extension radiographs in blunt pediatric cervical spine injury. Acad Emerg Med. 2001; 8:237–245.
241.
Ranjith RK, Mullett JH, Burke TE. Hangman's fracture cause by suspected child abuse. A case report. J Pediatr Orthop B. 2002; 11:329–332.
242.
Reilly CW, Leung F. Synchondrosis fracture in a pediatric patient. Can J Surg. 2005; 48:158.
243.
Reinges MH, Mayfrank L, Rohde V, et al. Surgically treated traumatic synchondrotic disruption of the odontoid process in a 15-month-old girl. Childs Nerv Syst. 1998; 14:85–87.
244.
Ricciardi JE, Kaufer H, Louis DS. Acquired os odontoideum following acute ligament injury. J Bone Joint Surg Am. 1976; 58:410–412.
245.
Richards PG. Stable fractures of the atlas and axis in children. J Neurol Neurosurg Psychiatry. 1984; 47:781–783.
246.
Ries MD, Ray S. Posterior displacement of an odontoid fracture in a child. Spine. 1986; 11:1043–1044.
247.
Ringel F, Reinke A, Stüer C, et al. Posterior C1-2 fusion with C1 lateral mass and C2 isthmic screws: Accuracy of screw position, alignment and patient outcome. Acta Neurochir. 2012; 154:305–312.
248.
Roche CJ, O'Malley M, Dorgan JC, et al. A pictorial review of atlantoaxial rotatory fixation: Key points for the radiology. Clin Radiol. 2001; 56:947–958.
249.
Rodgers WB, Coran DL, Emans JB, et al. Occipitocervical fusions in children. Retrospective analysis and technical considerations. Clin Orthop Relat Res. 1999; 364:125–133.
250.
Roy-Camille R, Saillant G, Mazel C. Internal fixation of the unstable cervical spine by posterior osteosynthesis with plates and screws. In: Sherk HH, ed. The Cervical Spine. 2nd ed. Philadelphia, PA: JB Lippincott; 1989:390–412.
251.
Ruff SJ, Taylor TKF. Hangman's fracture in an infant. J Bone Joint Surg Br. 1986; 68:702–703.
252.
Ruge JR, Sinson GP, McLone DG, et al. Pediatric spinal injury: the very young. J Neurosurg. 1988; 68:25–30.
253.
Sanborn MR, Diluna ML, Whitmore RG, et al. Fluoroscopically guided, transoral, closed reduction, and halo vest immobilization for an atypical C-1 fracture. J Neurosurg Pediatr. 2011; 7:380–382.
254.
Sankar WN, Wills BPD, Dormans JP, et al. Os odontoideum revisited: the case for a multifactorial etiology. Spine. 2006; 31:979–984.
255.
Sasaki H, Itoh T, Takei H, et al. Os odontoideum with cerebellar infarction. A case report. Spine. 2000; 25:1178–1181.
256.
Scannell G, Waxman K, Tominaga G, et al. Orotracheal intubation in trauma patients with cervical fractures. Arch Surg. 1993; 128(8):903–905.
257.
Scapinelli R. Three-dimensional computed tomography in infantile atlantoaxial rotatory fixation. J Bone Joint Surg Br. 1994; 76:367–370.
258.
Schiff DC, Parke WW. The arterial supply of the odontoid process. J Bone Joint Surg Am. 1973; 55:1450–1464.
259.
Schippers N, Könings P, Hassler W, et al. Typical and atypical fractures of the odontoid process in young children. Report of two cases and a review of the literature. Acta Neurochir (Wien). 1996; 138:524–530.
260.
Schuler TC, Kurz L, Thompson DE, et al. Natural history of os odontoideum. J Pediatr Orthop. 1991; 11:222–225.
261.
Schwartz GR, Wright SW, Fein JA, et al. Pediatric cervical spine injury sustained in falls from low heights. Ann Emerg Med. 1997; 30:249–252.
262.
Schwarz N, Genelin F, Schwarz AF. Posttraumatic cervical kyphosis in children cannot be prevented by nonoperative methods. Injury. 1994; 25:173–175.
263.
Segal LS, Drummond DS, Zanotti RM, et al. Complications of posterior arthrodesis of the cervical spine in patients who have Down syndrome. J Bone Joint Surg Am. 1991; 73:1547–1560.
264.
Seimon LP. Fracture of the odontoid process in young children. J Bone Joint Surg Am. 1977; 59:943–948.
265.
Shacked I, Ram Z, Hadani M. The anterior cervical approach for traumatic injuries to the cervical spine. Clin Orthop Relat Res. 1993; 292:144–150.
266.
Shaffer MA, Doris PE. Limitation of the cross-table lateral view in detecting cervical spine injuries: a retrospective review. Ann Emerg Med. 1981; 10:508–513.
267.
Shatney CH, Brunner Rd, Nguyen TQ. The safety of orotracheal intubation in patients with unstable cervical spine fracture or high spinal cord injury. Am J Surg. 1995; 170:676–679.
268.
Shaw BA, Murphy KM. Displaced odontoid fracture in a 9-month-old child. Am J Emerg Med. 1999; 1:73–75.
269.
Sherburn EW, Day RA, Kaufman BA, et al. Subdental synchondrosis fracture in children: the value of three-dimensional computerized tomography. Pediatr Neurosurg. 1996; 25:256–259.
270.
Sherk HH, Dawoud S. Congenital os odontoideum with Klippel-Feil anomaly and fatal atlantoaxial instability. Spine. 1981; 6:42–45.
271.
Sherk HH, Schut L, Lane J. Fractures and dislocations of the cervical spine in children. Orthop Clin North Am. 1976; 7:593–604.
272.
Sherk HH, Whitaker LA, Pasquariello PS. Fascial malformations and spinal anomalies: a predictable relationship. Spine. 1982; 7:526–531.
273.
Shulman ST, Madden JD, Esterly JR, et al. Transection of the spinal cord. A rare obstetrical complication of cephalic delivery. Arch Dis Child. 1971; 46:291–294.
274.
Sim F, Svien HJ, Bickel WH, et al. Swan neck deformity following extensive cervical laminectomy. J Bone Joint Surg Am. 1974; 56:564–580.
275.
Smith T, Skinner SR, Shonnard NH. Persistent synchondrosis of the second cervical vertebra simulating a hangman's fracture in a child. J Bone Joint Surg Am. 1993; 75:1228–1230.
276.
Special Olympics, Inc. Participation byIndividuals with DS Who Suffer from Atlantoaxial Dislocation. Washington, DC: Author; 1983.
277.
Spence KF Jr, Decker S, Sell KW. Bursting atlantal fracture associated with rupture of the transverse ligament. J Bone Joint Surg Am. 1970; 52(3):543–549.
278.
Spitzer R, Rabinowitch JY, Wybar KC. A study of the abnormalities of the skull, teeth and lenses in Mongolism. Can Med Assoc J. 1961; 84:567–572.
279.
Sponseller PD, Cass J. Atlanto-occipital arthrodesis for instability with neurologic preservation. Spine. 1997; 22:344–347.
280.
Sponseller PD, Herzenberg JE. Cervical spine injuries in children. In: Clark CR, Dvorak J, Ducker TB, et al, eds. The Cervical Spine. Philadelphia, PA: Lippincott-Raven; 1998: 357–371.
281.
Stauffer ES, Mazur JM. Cervical spine injuries in children. Pediatr Ann. 1982; 11:502–511.
282.
Steel HH. Anatomical and mechanical consideration of the atlantoaxial articulation. J Bone Joint Surg Am. 1968; 50:1481–1482.
283.
Steinmetz MP, Lechner RM, Anderson JS. Atlantooccipital dislocation in children: Presentation, diagnosis, and management. Neurosurg Focus. 2003; 14:1–7.
284.
Stevens JM, Chong WK, Barber C, et al. A new appraisal of abnormalities of the odontoid process associated with atlantoaxial subluxation and neurological disability. Brain. 1994; 117:133–148.
285.
Stillwell WT, Fielding W. Acquired os odontoideum. Clin Orthop Relat Res. 1978; 135:71–73.
286.
Sun PP, Poffenbarger GJ, Durham S, et al. Spectrum of occipitoatlantoaxial injury in young children. J Neurosurg. 2000; 93(Suppl 1):28–39.
287.
Swischuk EH Jr, Rowe ML. The upper cervical spine in health and disease. Pediatrics. 1952; 10:567–572.
288.
Swischuk LE. Spine and spinal cord trauma in the battered child syndrome. Radiology. 1969; 92:733–738.
289.
Tauchi R, Imagama S, Ito Z, et al. Complications and outcomes of posterior fusion in children with atlantoaxial instability. Eur Spine J. 2012; 21:1346–1352.
290.
Tawbin A. CNS damage in the human fetus and newborn infant. Am J Dis Child. 1951; 33:543–547.
291.
Taylor AR. The mechanism of injury to the spinal cord in the neck without damage to the vertebral column. J Bone Joint Surg Br. 1951; 33:453–547.
292.
Thakar C, Harish S, Saifuddin A, et al. Displaced fracture through the anterior atlantal synchondrosis. Skeletal Radiol. 2005; 34:547–549.
293.
Tolo VT, Weiland AJ. Unsuspected atlas fractures and instability associated with oropharyngeal injury: Case report. J Trauma. 1979; 19:278–280.
294.
Traynelis VC, Marano GD, Dunker RO, et al. Traumatic atlanto-occipital dislocation: Case report. J Neurosurg. 1986; 65:863–870.
295.
Tredwell SJ, Newman DE, Lockitch G. Instability of the upper cervical spine in Down syndrome. J Pediatr Orthop. 1990; 10:602–606.
296.
Tuli S, Tator CH, Fehlings MG, et al. Occipital condyle fractures. Neurosurgery. 1997; 41:368–377.
297.
Uchiyama T, Kawaji Y, Moriya K, et al. Two cases of odontoid fracture in preschool children. J Spinal Disord Tech. 2006; 19:204–207.
298.
Vanderhave KL, Chiravuri S, Caird MS, et al. Cervical spine trauma in children and adults: Perioperative considerations. J Am Acad Orthop Surg. 2011; 19:319–327.
299.
Van Dyke DC, Gahagan CA. Down syndrome: cervical spine abnormalities and problems. Clin Pediatr. 1988; 27:415–418.
300.
van Rijn RR, Kool DR, de Witt Hamer PC, et al. An abused 5-month-old girl: Hangman's fracture or congenital arch defect? J Emerg Med. 2005; 29:61–65.
301.
Verska JM, Anderson PA. Os odontoideum. A case report of one identical twin. Spine. 1997; 22:706–709.
302.
Viccellio P, Simon H, Pressman BD, et al. A prospective multicenter study of cervical spine injury in children. Pediatrics. 2001; 108:E20.
303.
Visocchi M, Fernandez E, Ciampini A, et al. Reducible and irreducible os odontoideum in childhood treated with posterior wiring, instrumentation and fusion. Past or present? Acta Neurochir. 2009; 151:1265–1274.
304.
Walsh JW, Stevens DB, Young AB. Traumatic paraplegia in children without contiguous spinal fracture or dislocation. Neurosurgery. 1983; 12:439–445.
305.
Wang J, Vokshoor A, Kim S, et al. Pediatric atlantoaxial instability: management with screw fixation. Pediatr Neurosurg. 1999; 30:70–78.
306.
Wang MY, Hoh DJ, Leary SP, et al. High rates of neurological improvement following severe traumatic pediatric spinal cord injury. Spine. 2004; 29:1493–1497; discussion E1266.
307.
Ware ML, Gupta N, Sun PP, et al. Clinical biomechanics of the pediatric craniocervical junction and the subaxial spine. In: Brockmeyer DL, ed. Advanced Pediatric Craniocervical Surgery. New York, NY: Thieme; 2006: 27–42.
308.
Warner WC. Pediatric cervical spine. In: Canale ST, ed. Campbell's Operative Orthopaedics. St. Louis, MO: Mosby; 1998.
309.
Warner WC Jr. Pediatric cervical spine. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics. 12th edition. Philadelphia, PA; Elsevier; 2013.
310.
Watanabe M, Toyama Y, Fujimura Y. Atlantoaxial instability in os odontoideum with myelopathy. Spine. 1996; 21:1435–1439.
311.
Wertheim SB, Bohlman HH. Occipitocervical fusion: Indications, technique, and longterm results. J Bone Joint Surg Am. 1987; 69:833–836.
312.
Wetzel FT, Larocca H. Grisel syndrome. A review. Clin Orthop Relat Res. 1989; 240:141–152.
313.
White AA III, Johnson RM, Panjabi MM, et al. Biomechanical analysis of clinical stability in the cervical spine. Clin Orthop Relat Res. 1975; 109:85–96.
314.
White AA III, Panjabi MM. The basic kinematics of the human spine. A review of past and current knowledge. Spine. 1978; 3:12–20.
315.
Williams JP III, Baker DH, Miller WA. CT appearance of congenital defect resembling the hangman's fracture. Pediatr Radiol. 1999; 29:549–550.
316.
Wills BPD, Jencikova-Celerin L, Dormans JP. Cervical spine range of motion in children with posterior occipitocervical arthrodesis. J Pediatr Orthop. 2006; 26(6):753–757.
317.
Wind WM, Schwend RM, Larson J. Sports for the physically challenged child. J Am Acad Orthop Surg. 2004; 12:126–137.
318.
Windell J, Burke SW. Sports participation of children with Down syndrome. Orthop Clin North Am. 2003; 34:439–443.
319.
Wollin DG. The os odontoideum. J Bone Joint Surg Am. 1971; 45:1459–1471.
320.
Yasuoko F, Peterson H, MacCarty C. Incidence of spinal column deformity after multiple level laminectomy in children and adults. J Neurosurg. 1982; 57:441–445.
321.
Yngve DA, Harris WP, Herndon WA, et al. Spinal cord injury without osseous spine fracture. J Pediatr Orthop. 1988; 8:153–159.