Bilateral locked facets of the cervical spine

Abstract

Bilateral locked facets (BLF) is a relatively common, unstable injury of the cervical spine. Severe neurologic deficit often is present due to marked narrowing of the spinal canal. Occasionally, BLF may be associated with ring-disrupting posterior element fractures. It has been suggested in the literature that associated ring-disrupting fractures decompress the spinal canal, preserving neurologic function. To evaluate this assertion, we reviewed the medical records and radiologic studies of 31 patients with BLF, collected at our institution over the past 15 years. Complete (Frankel A) or incomplete (Frankel B, C) neurologic deficit was present in 24 (77%) patients and minimal or no neurologic deficit (Frankel D, E) in the remaining 7 patients. Radiologically detected fractures associated with BLF were noted in 11 (35%) patients, of which 9 (29%) involved either bilateral laminar or pedicle fractures (ring-disrupting) at the level of dislocation, theoretically allowing decompression of the spinal canal. However, no statistically significant association between the presence of ring-disrupting fracture and minimal or no neurologic deficit was found. Our study suggests that ring-disrupting posterior element fractures associated with BLF do not necessarily offer protection to the spinal cord and that dynamic factors at the time of injury are primarily responsible for eventual neurologic outcome.