Posterior atlanto-axial fusion with the Olerud Cervical Fixation System for odontoid fractures and C1-C2 instability in rheumatoid arthritis.

In posterior C1-C2 fusion, traditional wire fixation gives poor stability. The bone quality is often insufficient to provide the competent structural bone graft that is required, and the introduction of sublaminar wires is somewhat dangerous. The stability is markedly improved by adding transarticular screws, but the drawbacks of structural bone graft and sublaminar wires remain. The C1 claw of the Olerud Cervical Fixation System improves C1-C2 fixation without relying on structural bone graft or compromising the spinal canal. The aim of this study was to evaluate radiological healing and possible complications in a consecutive series of C1-C2 fusions from our department operated with the C1 claw device. Twenty-six patients (14 women) with a mean age of 73 (range 37-93) years were included. The diagnoses were odontoid fracture in 18 patients, rheumatoid instability in 6, and odontoid non-union and os odontoideum in 1 each. The patients were followed clinically and with plain radiographs for an average of 15 (range 3-27) months. There were no neurological or vascular complications, and no secondary displacements or reoperations in the series. Twenty patients followed for 6-27 months were radiographically healed. Six patients died from unrelated causes 1-38 months postoperatively. Three of these patients had no radiographs later than the postoperative control, one had a healed odontoid fracture but resorbed bone graft at 8 months, while the remaining two patients were not healed, but showed no signs of healing disturbance at the time of death. On the basis of the findings of this study, posterior C1-C2 fusion with the Olerud Cervical Fixation System seems promising. No serious complications related to the surgical procedure were encountered. The stability of the implant obviates the use of a solid bone block as a graft and still allows a high frequency of fusion healing.