C1-C2 transarticular screw fixation for atlantoaxial instability: a 6-year experience.

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 age of 44 years (range, 8-76 yr). Each patient had documented atlantoaxial instability. 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 stabilization with C1-C2 transfacetal screws and a posterior interspinous construct. Nine patients had unilateral screws placed. Postoperatively, the patients were maintained in a rigid cervical orthosis for a mean of 11 weeks (range, 8-15 wk); five patients were immobilized with halo fixation for a mean of 13 weeks (range, 10-16 wk). The mean follow-up period was 2.4 years (range, 1-5.5 yr). RESULTS: Osseous fusion was documented in 72 patients (96%). There were no hardware failures; however, three patients developed pseudarthrosis. Two superficial wound infections (one at the graft site and one at the cervical incision site) required antibiotic therapy. Four patients had transient suboccipital hypesthesia. No instances of an errant screw, dural laceration, or injury to the vertebral artery, spinal cord, or hypoglossal nerve were noted. CONCLUSION: C1-C2 transarticular screw fixation supplemented with an interspinous construct yielded a 96% fusion rate, with a low incidence of complications. We attribute our successful outcomes to careful preoperative assessment and meticulous surgical technique.