C2 Nerve Root Sectioning in Posterior C1-2 Instrumented Fusions

OBJECTIVE: To analyze qualitatively C2 nerve dysfunction after its transection in C1-2 posterolateral instrumented fusions. METHODS: From 2002-2010, 20 consecutive patients underwent posterolateral instrumented fusions using C1 lateral mass and C2 pars or pedicle screws, mainly for type 2 dens fractures. Screws were placed under lateral fluoroscopic guidance using standard techniques. Bilateral C2 nerve roots were coagulated and transected in all patients. Mean follow-up was 30.7 months and consisted of clinical and radiographic examinations, telephone interviews, and mailed visual analogue scale (VAS) questionnaires assessing C2 nerve dysfunction. RESULTS: One patient was lost to follow-up after the initial postoperative visit. Fusion was evident in all patients with 12 months of follow-up and two of three patients with <12 months of follow-up. There were no instances of unintended neurologic deficits, vascular injury, cerebrospinal fluid (CSF) leak, or hardware malfunction or malposition. By the 2-week or 6-week office visit, 4 of 20 patients complained of sensory disturbance, and 2 had paresthesias in the C2 distribution. After longer follow-up, one additional patient developed mild sensory symptoms. Quality of life was adversely affected in only one patient. No patient developed neuropathic pain at any time after C2 sectioning. CONCLUSIONS: This study is the first series to describe C2 nerve function after posterior atlantoaxial instrumented fusion in adults of all ages. Sacrifice of the C2 nerve root increases fusion surface, allows for better preparation and decortication of the atlantoaxial joint, improves visualization for screw placement, and decreases blood loss and operative time without major clinical consequences.