Mini-open percutaneous transarticular screw fixation for acute and late atlantoaxial instability.

The treatment of atlantoaxial instability by means of posterior transarticular screw fixation combined with a Gallie fusion is an established method when direct anterior odontoid screw fixation is not indicated or has failed. In this retrospective study, the results of a modified percutaneous mini-open transarticular C1-C2 screw fixation are presented. Between February 1998 and March 2006, 47 patients with acute or late (after failed conservative treatment) atlantoaxial instability were treated with the modified technique. Their average age was 74.9 years. There were no intraoperative injuries to neural structures or blood vessels; 96.8% of the screws were placed correctly. A revision operation was necessary in one patient because of infection at the graft donor site. No patient experienced a neurological complication. Three patients died during hospitalisation, 6 others later on; 6 could not be traced, leaving thirty-two patients or 68% available for follow-up. The average clinical follow-up was 42 months (range: 12 to 91). The results with respect to the pain and activity status were good or excellent in more than 90% of cases. The radiographic follow-up averaged 25 months (range: 12 to 75). Bony fusion was documented in all cases. The modified technique of transarticular screw fixation presented here is a safe and functionally satisfactory method of achieving stabilisation of the atlantoaxial complex. Special cannulated instruments are not required. This mini-open transcutaneous technique is an alternative to the conventional open procedure, and reduces operation time as well as blood loss.