C1-C2 transarticular screw fixation for atlantoaxial instability: A 6-yearexperience

OBJECTIVE: We review a 6-year, single-center experience using the technique of C1-C2 transarticular screw fixation for atlantoaxial instability in 75 consecutive operations. METHODS: The study group was composed of 43 men and 32 women, with a mean a ge of 44 years (range, 8-76 yr). Each patient had documented atlantoaxial i nstability. In 28 patients (37%), atlantoaxial instability was a result of trauma; in 22 patients, (29%), it was a result of rheumatoid arthritis; in 16 patients (21%), it was a result of prior surgery; and in 9 patients (12% ), it was a result of congenital abnormalities. All patients underwent stab ilization with C1-C2 transfacetal screws and a posterior interspinous const ruct. Nine patients had unilateral screws placed. Postoperatively, the pati ents were maintained in a rigid cervical orthosis for a mean of 11 weeks (r ange, 8-15 wk); five patients were immobilized with halo fixation for a mea n of 13 weeks (range, 10-16 wk). The mean follow-up period was 2.4 years (r ange, 1-5.5 yr). RESULTS: Osseous fusion was documented in 72 patients (96%). There were no hardware failures; however, three patients developed pseudarthrosis. Two su perficial wound infections tone at the graft site and one at the cervical i ncision site) required antibiotic therapy. Four patients had transient subo ccipital hypesthesia. No instances of an errant screw, dural laceration, or injury to the vertebral artery, spinal cord, or hypoglossal nerve were not ed. CONCLUSION: C1-C2 transarticular screw fixation supplemented with an inters pinous construct yielded a 96% fusion rate, with a low incidence of complic ations. We attribute our successful outcomes to careful preoperative assess ment and meticulous surgical technique.