Cervical Spine Trauma in Children: A Review

Todd Mccall, MD; Dan Fassett, MD; Douglas Brockmeyer, MD

Disclosures

Neurosurg Focus. 2006;20(2):E5 

In This Article

Neuroimaging Studies

Plain Radiographs

Multiple studies have been conducted in an attempt to stratify pediatric patients into low- and high-risk groups and to try to identify which patients require static cervical spine x-ray films (AP and lateral) to evaluate for traumatic injury. Laham, et al.,[55] defined low-risk patients as those who were able to communicate verbally and had no cervical discomfort. Of the 135 children at low risk who were studied retrospectively, no cases of cervical spine injury were diagnosed using plain x-ray films.

More recently, a prospective multicenter trial was conducted to evaluate the NEXUS decision instrument for identifying pediatric patients who have suffered blunt trauma and in whom radiographs of the cervical spine should be obtained.[99] Low-risk patients must meet all five NEXUS criteria, which are as follows: 1) absence of midline cervical tenderness; 2) no evidence of intoxication; 3) normal level of alertness; 4) normal results on neurological examination; and 5) absence of a painful or distracting injury. If a patient fulfills all five of the NEXUS criteria, plain radiographs are of marginal value. None of the 603 children designated as low-risk had evidence of cervical spine trauma on plain x-ray films. Of note, approximately 1% of patients who did not meet all of the NEXUS criteria had a cervical spine injury. Most patients for whom a trauma response is activated do not meet all of the NEXUS criteria acutely, and therefore at our institution we initially obtain anterolateral and posterior x-ray films as a component of the trauma protocol in all of these patients.

The usefulness of an odontoid view in very young children is questionable. In a retrospective review, 10 patients younger than 9 years of age who had sustained a cervical spine injury between the occiput and C-3 were identified, but in none of these cases was the diagnosis based on a transoral odontoid plain x-ray film.[17] In another study that was based on a questionnaire, investigators suggested that children younger than 5 years of age do not require a transoral x-ray film as part of a trauma protocol.[95] At our institution, in children 5 years of age or younger we obtain only AP and lateral plain x-ray films when the trauma protocol has been activated, whereas children older than 5 years also undergo a transoral view.

Flexion and extension radiographs are still the gold standard for evaluating instability of the cervical spine. If a patient does not meet the NEXUS criteria but has normal results on AP and lateral views, then flexion and extension views are indicated to evaluate stability. Dynamic x-ray films should be obtained only if the patient is neurologically intact. Otherwise, MR imaging should be considered for further evaluation. The authors of some studies suggest that if results of AP and lateral x-ray films are normal, however, then the value of dynamic films is disputable.[29,77] Dynamic views are often unsatisfactory initially because of muscle spasms, and in these cases the studies must be repeated once the spasm has resolved.

Usefulness of CT Scans

For children younger than 10 years of age, the benefit of CT scans for diagnosing cervical injuries is limited because most of these types of injuries in this age group are ligamentous, with no osseous component.[26,41] Even in children older than 10 years, 20% of cervical injuries will be ligamentous and will not involve a fracture.[31,99] Therefore, normal anatomical findings on a CT scan cannot be used to exclude a cervical injury in children and should not be used exclusively for cervical spine clearance.[81] Still, CT scans are superior to radiographs for defining bone anatomy and are a useful adjunct to other imaging modalities for presurgical planning.

Usefulness of MR Imaging

An MR imaging session can provide several useful functions in the setting of pediatric cervical spine trauma. First, MR imaging can be used to clear the cervical spine of a child if initial plain x-ray films show normal results but the child is obtunded, intubated, or uncooperative.[35] Also, if results on plain x-ray films or CT scans are equivocal, an MR image can also be used to clear the cervical spine. Second, if a child has persistent or delayed neurological symptoms with normal findings on x-ray films and a CT scan, an MR imaging study may reveal soft-tissue, ligamentous, or disc injury that would otherwise remain unrecognized. In one study of 52 pediatric patients with trauma, 31% had significant MR imaging findings, and in four of these children the results of MR imaging directly influenced the surgical management.[51] Finally, in cases of SCI, MR imaging can provide useful prognostic information.[23]

Pitfalls of Neuroimaging in Pediatric Patients

The radiographic appearance of the cervical spine in children differs in several ways from that of adults, and to further complicate matters, these differences change with age. As a result, pediatric cervical spine injuries can often have a delayed or inaccurate diagnosis. In a retrospective review of 37 trauma cases, a misdiagnosis was identified in 24% of cases involving children younger than 9 years of age and in 15% of cases in which the child was 9 years of age or older.[6]

Pseudosubluxation in the upper cervical spine of children is considered a normal finding.[74,86] To determine the incidence of pseudosubluxation, Cattell and Filtzer[20] evaluated 160 pediatric patients ranging from 1 to 16 years of age. They found that among children younger than 8 years, at least 3 mm of anterior displacement was present in 40% at C2-3, and in 14% of children it was present at C3-4. In pediatric patients with trauma, pseudosubluxation is not associated with intubation, injury severity, or outcome, from which we infer that pseudosubluxation is an incidental finding in these cases.[84] The only variable that correlates with pseudosubluxation appears to be age; this condition occurs in children up to 14 years of age. Shaw and colleagues[84] have provided strict criteria for determining the presence of pseudosubluxation. A line drawn through the posterior arches of C-1 and C-3 should touch, pass through, or lie within 1 mm anterior to the anterior cortex of the posterior arch of C-2. If none of these conditions is met, then true dislocation should be suspected.

A second common feature of the pediatric spine that can be misleading is the collection of synchondroses in all cervical vertebrae. The C-2 vertebra, which is especially prone to injury in these young children, has a total of three synchondroses between the dens, body, and arch, which usually close between the ages of 3 and 7 years.[7,94] Of these three synchondroses, the densarch one is most pronounced and is therefore most frequently mistaken for a fracture. A key feature that distinguishes the densarch synchondrosis from a true fracture is that the synchondrosis is visible on an oblique but not on a straight lateral x-ray film. Subaxial vertebrae in young children will have synchondroses between the posterior and anterior elements, which can be mistaken for fractures.

Other radiographic features that may be misread as evidence of cervical spine injury include a lack of cervical lordosis and notable angulation at individual intervertebral spaces.[20,92] Pronounced vascular channels in the ossification center can be misconstrued as fractures.[43]

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