The impact of facet dislocation on clinical outcomes after cervical spinal cord injury: Results of a multicenter North American prospective cohort study

STUDY DESIGN.: A multicenter prospective cohort study. OBJECTIVE.: To define differences in baseline characteristics and long-term clinical outcomes in patients with cervical spinal cord injury (SCI) with and without facet dislocation (FD). SUMMARY OF BACKGROUND DATA.: Reports of dramatic neurological improvement in patients with FD and cervical SCI, treated with rapid reduction have led to the hypothesis that this represents a subgroup of patients with significant recovery potential. However, without a large systematic comparative analysis, this hypothesis remains untested. METHODS.: Patients were classified into FD and non-FD groups based on imaging investigations at admission. The primary outcome was change in American Spinal Injury Association (ASIA) motor score (AMS) at 1-year follow-up. Secondary outcome measures included ASIA impairment scale (AIS) grade conversion and functional independence measure score at 1-year postinjury, as well as length of acute hospitalization. Baseline characteristics and long-term outcomes were also compared for patients with unilateral and bilateral FD. RESULTS.: Of 421 patients who enrolled, 135 (32.1%) had FD and 286 (67.9%) had no FD. Patients in the FD group presented with a significantly worse AIS grade and higher energy injury mechanisms (P < 0.01). Patients with bilateral FD had a greater severity of baseline neurological deficit compared with those with unilateral FD, measured by AIS grade and AMS. The mean length of acute hospitalization was 41.2 days among patients with FD and 30 days among patients without FD (P = 0.04). At 1-year follow-up, patients with FD experienced a mean AMS improvement of 18.0 points, whereas patients without FD experienced an improvement of 27.9 points (P < 0.01). In the adjusted analysis, patients with FD continued to demonstrate less AMS recovery compared with the patients without FD (P = 0.04). CONCLUSION.: Compared with patients without FD, cervical SCI patients with FD tended to present with a more severe degree of initial injury and displayed less potential for motor recovery at 1-year follow-up.