Abstract: objective:To explore the surgical feasibility of C1-C2 pedicle screw instrument by direct vision in atlas.Method:12 adult patients with atlantoaxial instability were treated with C1-C2 pedicle screws instrument by direct vision under general anesthesia.Bone graft were administered in all patients.Result:A total of 24 screws were successfully placed in atlas.All patients were followed up from 3 to 15 months,averaged 4.2 months.No cases of implant failure were observed,and there were no neural or vascular injure.All patients had a bone fusion on radiographs after three or six months.Conclusion:The application of C1-C2 pedicle screw instrument by direct vision in atlas is safe,and the clinical result is satisfactory.

Key words: atlas;pedicle , screw;internal fixation