OBJECTIVETo explore the feasibility of C1-2 pedicle screw fixation and fusion technique in treating atlantoaxial instability.

METHODSFrom January 2006 to January 2009,18 patients with atlantoaxial instability were treated with C1-2 pedicle screws and plates fixation under general anesthesia. There were 11 males and 7 females, the age for 17-62 years with the mean of 37.7 years. The course of disease was from 3 days to 30 months with an average of 10.6 months. The patients had different degrees neck pain and disturbance of sensation or (and) dyskinesia, had atlantoaxial instability from images before operation. The JOA scoring before operation were from 8 to 15 with an average of 11.4. Bone fusion of patients was observed with X-rays, CT and MR image at the same time after operation and the JOA scoring was compared with preoperative.

RESULTSA total of 72 screws were successfully placed in 18 cases, among them, 15 cases were followed up from 6 to 24 months with an average of 11.5 months. Fifteen cases obtained bone fusion with time for 3-6 months without the complications of internal fixation failure or redislocation of atlas. The spinal compression had differently improved, postoperative JOA scoring was from 12 to 17 scores with an average of 14.5 scores.

CONCLUSIONPedicle screw fixation and fusion in atlas has advantages of firm fixation and high fusion rate, it is a better choices for atlantoaxial instability. It is not suitable for variations of sulcus of vertebral artery of atlas and posterior arch of atlas.