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

Evaluating Cervical Stability

Several methods have been developed to determine cervical spine stability. Some rely on objective measurements, whereas others are more descriptive. No individual method is definitive, but they all have value in that they provide a systematic approach to this difficult and often confusing clinical dilemma.

In a study of adult cadavers performed by White and colleagues,[103] when all ligaments were intact the horizontal motion of one VB on the next did not exceed 3.5 mm and the angular displacement of one VB on another did not exceed 11°. These results became the basis for the well-accepted radiographic criteria of cervical instability proposed by White and Panjabi.[104] Specifically, cervical spine instability should be considered when a static lateral x-ray film demonstrates sagittal plane displacement of greater than 3.5 mm or relative plane angulation of greater than 11° in the setting of acute trauma. In one series,[105] however, investigators identified eight patients with occult cervical ligamentous instability and ages ranging from 18 to 23 years who did not meet the criteria of White and Panjabi for instability.

Applying the criteria of White and Panjabi to the pediatric spine is problematic because increased elasticity due to factors discussed previously allows for more recoil of the spine after injury. The increased recoil helps restore alignment to the cervical spine following injury, and therefore the upper limit of acceptable angulation in children needs to be lower than that in adults. Currently, angulation greater than 7° is considered a sign of ligamentous injury in the pediatric cervical spine.[102] Furthermore, 3.5 mm of subluxation in children may be physiological, based on studies describing pseudosubluxation.[20] Therefore, if a child is younger than 8 years of age, cervical instability should be considered if more than 4.5 mm of subluxation is present at C2-3 or C3-4, and greater than 3.5 mm of subluxation should not be tolerated at any level in patients older than 8 years of age.[71]

Another paradigm for evaluating the spine is the two-column model, in which the cervical spine is divided into anterior and posterior columns.[47,79] The anterior column consists of the anterior longitudinal ligament, VB, posterior longitudinal ligament, anterior and posterior portions of the anulus fibrosus, and the intertransverse ligaments. The posterior column includes the pedicles, laminae, transverse processes, spinous process, interspinous ligaments, supraspinous ligaments, ligamentum flavum, and capsular ligaments. In adults, the spine remains stable under physiological loads if all of the anterior and one posterior element or all of the posterior and one anterior element are intact.[73,103] A three-column model has also been proposed, but it was developed in a retrospective review of thoracolumbar injuries and does not provide much added benefit for clinical decisions regarding the cervical spine.[25] The two-column model fits nicely with the binary option of surgical approaches, these being either anterior or posterior.

Spine stability may also be considered with respect to the type of cervical injury. Anterior wedge compression fractures are usually stable, although greater than 15° of VB angulation should be considered a sign of instability. Tear-drop fractures can be unstable, depending on the severity of injury to the disc, facet joints, and anterior and posterior ligaments.[42] Unilateral or bilateral locked facets, burst fractures, and fracture-dislocations are unstable, and ligamentous injury without an associated fracture may be either stable or unstable.

Physial injuries are specific to young children, occurring when the vertebral endplate is separated from the body through the epiphysis. Autopsy findings in 12% of juvenile trauma cases revealed a physial injury, most commonly involving the inferior endplate.[5] Salter-Harris Type I injuries (in which the epiphysis is intact but separated from the metaphysis) are very unstable, require surgical stabilization, and are seen in infants and young children. Type III injuries (in which the fracture traverses the epiphysis and extends into the epiphysial plate), which may be treated with immobilization, are associated with older adolescents.[56,67] These injuries can be difficult to diagnose on plain radiographs; often the only finding is widening of the intervertebral disc space.

Delayed or occult cervical instability is defined as "instability at least 20 days after trauma, in patients who underwent sufficiently thorough x-ray investigations during the acute phase who either did not present traumatic lesions or had only minimal lesions initially judged to be stable."[24] Occult cervical instability has been described in both adult and pediatric populations, although patients younger than 25 years may be at higher risk.[45,105] Because it is difficult to predict which patients will experience delayed cervical instability, some authors recommend a complete radiographic and clinical reevaluation 3 weeks after injury in all patients in whom these studies are normal initially.[45,105] Although these recommendations will not always be practical, patients considered to have a high risk for delayed cervical instability include those with neurological deficits, persistent pain, microfractures, dislocations less than 3 mm, or inversion of physiological lordosis.[24]

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