Computer-assisted Magerl's transarticular screw fixation for atlantoaxial subluxation.

We report two patients with rheumatoid arthritis in whom posterior atlantoaxial fixation was carried out using transarticular screws with computer assistance. Two bilateral transarticular screws were inserted in one patient; however, in the other patient, only a unilateral screw was used, because computerized images showed that the vertebral artery at the other side was placed too medially to allow insertion of the screw. Neither of these patients had any neurovascular complications after surgery. Computer-assisted surgery is useful for avoiding neurovascular complications with transarticular screw fixation of C1-2.