[Minimally invasive anterior transarticular screw fixation and fusion for atlantoaxial instability].

OBJECTIVE: To investigate the clinical results and complications of minimally invasive anterior transarticular screw fixation and fusion for atlantoaxial instability.

METHODS: Between May 2007 and December 2010, 13 patients with atlantoaxial instability were treated with minimally invasive anterior transarticular screw fixation and fusion under endoscope. There were 11 males and 2 females, aged 17-61 years (mean, 41.3 years). The time between injury and operation was 5-14 days (mean, 7.4 days). All cases included 6 patients with Jefferson fracture, 5 with odontoid fracture, and 2 with os odontoideum. According to Frankel classification of nerve functions, 2 cases were rated as grade D and 11 cases as graed E. The operation time, intra-operative blood loss, radiation exposure time, and complications were recorded and analyzed. The stability was observed by X-ray films. The clinical outcome was assessed using the Frankel scale, and the fusion rates were determined by CT scan three-dimensional reconstruction at last follow-up.

RESULTS: The mean operation time was 124 minutes (range, 95-156 minutes); the mean intra-operative blood loss was 65 mL (range, 30-105 mL); and the mean radiation exposure time was 41 seconds (range, 30-64 seconds). Thirteen patients were followed up 12-47 months (mean, 25.9 months). No blood vessel and nerve injuries or internal fixator failure occurred. The bone fusion time was 6 months, and the dynamic cervical radiography showed no instability occured. At last follow-up, the neurological function was grade E in all patients. The fusion rate was 84.6% (11/13). No continuous bone bridge was seen in the joint space of 2 patients, but they achieved stability.

CONCLUSION: Minimally invasive anterior transarticular screw fixation and fusion is a safe and effective procedure for treatment of atlantoaxial instability.