Posterior C1-C2 transarticular screw fixation for Atlanto-axial instability.

ABSTRACT

The objective of this study was to reveal that the treatment of C1-C2 instability by transarticular C1-C2 screw fixation with bone graft has a better result than conventional sublaminar wiring with bone graft by Gallie's technique. This technique, proposed by Magerl and Semann in 1987, produces a rigid three points fixation resulting in maximal bone fusion rate and does not require an orthosis post-operatively. This technique is performed in patients with fractured lamina of C1 or in patients who need a laminectomy of C1 for spinal cord decompression. This study revealed 10 patients having C1-C2 instability who were operated on by transarticular C1-C2 screw fixation with bone graft. No complication was encountered. No screw and bone graft slipping were noted. The patients were improved clinically and the average follow-up period was 7.7 months. There were 2 cases which had previously been operated on for sublaminar wiring but the operation was unsuccessful because there was a fractured lamina of C1. Both patients were sent to Prasat Neurological Institute & Hospital for transarticular C1-C2 screw fixation. Another 2 cases were operated on for sublaminar wiring with bone graft. The follow-up X-ray of both cases disclosed a displacement of C1-C2. Lost of C1 lamina was found in one case and there was slipping of wire in another case, because of this the patients were re-explored for transarticular C1-C2 screw fixation with bone graft. The conclusion is, this technique of transarticular C1-C2 screw fixation, is the best surgical treatment for C1-C2 instability, in the hands of experienced surgeons with an excellent knowledge of anatomy.