Vertebral artery injury in destabilized midcervical spine trauma; predisposing factors and proposed mechanism.

BACKGROUND

By now it has been well established that vertebral artery injury (VAI) is associated with unstable cervical spine injuries resulting from blunt trauma. A more complete understanding of predisposing factors and the mechanism of injury in VAI should result in improved outcomes and reduced risk for patients with VAI associated with unstable cervical spine injury following blunt trauma. The authors report statistical outcome and hypothesis to more thoroughly examine the predisposing factors for VAI, of which management is controversial, in destabilized midcervical spine trauma.

METHODS

Ninety-one of 131 consecutive patients who underwent surgery for a traumatically destabilized subaxial cervical spine were included, and results were analyzed statistically by logistic regression.

RESULTS

Eighteen patients (19.8 % of 91 patients) had a VAI associated with midcervical spine trauma (C2-C6). In univariate statistical analysis, transverse foramen fracture (P = 0.002), facet dislocation (P = 0.014), and facet fracture (P = 0.001) were significant risk factors. However, only facet fracture was determined to be significant risk factor after multivariate analysis (P = 0.006, odds ratio 20.98). It is hypothesized that a VAI occurs in a midcervical spine injury when a facet fracture allows the bony compartment to impinge on the relatively narrow free space of the intervertebral foramen, which is also occupied by the cervical root.

CONCLUSION

A facet fracture is the most important risk factor for VAI in patients with a destabilized midcervical spine injury. Patients with a C2-C6 facet fracture may require a definitive evaluation with vertebral artery imaging.