location ~75% of all facet dislocations occur within the subaxial spine (C3 to C7)
17% of all injuries are fractures of C7 or dislocation at the C7-T1 junction this reinforces the need to obtain radiographic visualization of the cervicothoracic junction Pathophysiology mechanism flexion and distraction forces +/- an element of rotation
Cervical facet dislocations are among the most common traumatic spinal injuries.
The injury usually results from forced flexion of the cervical spine. However, where there is a degree of rotation, the facet dislocation may only occur to one facet joint:
bilateral facet dislocation: unstable
unilateral facet dislocation: stable
Facet dislocation can occur to varying degrees:
Represent spectrum of osteoligamentous pathology that includes unilateral facet dislocation most frequently missed cervical spine injury on plain xrays leads to ~25% subluxation on xray associated with monoradiculopathy that improves with traction
bilateral facet dislocation leads to ~50% subluxation on xray often associated with significant spinal cord injury facet fractures more frequently involves superior facet may be unilateral or bilateral.
A database search identified 96 patients (mean age = 37.9, range = 14-74 yr, 68 (70%) male. The most common affected levels were C4-C5 (30), C5-C6 (29), and C6-C7 (30). Bilateral dislocation occurred in 51 patients (53%). Seventy-eight (81%) patients had neurological deficits, 31 (32%) being complete (Abbreviated Injury Score A) spinal cord injuries. Preoperative closed reduction was attempted in 60 (63%) patients, with 33 (55%) achieving satisfactory alignment. After anterior cervical discectomy, reduction, allograft placement, and instrumentation, a total of 92 (96%) patients had achieved satisfactory realignment. Median time to surgery was 13.27 h. Eight (8%) patients required posterior fixation due to intraoperative determination of incomplete realignment (4; 4%) and development of early progressive deformity (4; 4%). Mean follow-up was 4.5 mo (range 0.5-24 mo) with 33 (34%) patients lost to follow-up.
Anterior approaches are viable for reduction and stabilization of cervical facet dislocations. Further prospective studies are required to evaluate clinical and long-term success 1).