OBJECTIVETo evaluate the operative strategy and therapeutic outcomes of the atlantoaxial instability.

METHODSClinical data of 29 patients with atlantoaxial instability were retrospectively analyzed. There were 27 males and 2 females. The mean age was 33 years old with a range from 18 to 54 years. There were fracture of anterior arch of atlas accompanied with ligamentum transversum rupture in 5 cases, odontiod fracture in 7 cases, Hangman fracture in 6 cases, dysplasia of atlas and axis in 10 cases, ankylosing spondylitis in 1 case. The clinical and imaging manifestation of atlantoaxial instability were found in all patients. The symptoms and physical signs of superior cervical spinal cord disease or cervical spinal injury were found in 18 cases. The patients were treated with simple modified Magerl method (7 cases), cannutated screw fixation(6 cases), resection of C2,3 disc throuth the anterior approach and fusion with Zephir titanium plate (4 cases), percutaneous pedicle screw fixation of C2 (2 cases), release and reduction through anterior oropharynx (LRAO) combined with modified Magerl method (4 cases), LRAO and atlas lateral mass screw and plate fixation through posterior approach (3 cases), cervical occipital fusion through C2 pedicle (3 cases).

RESULTSAll patients were followed up with an average time of 17.2 months ranging from 11 to 38 months. All patients obtained anatomical reduction and bone healing. Using Odom standard to evaluation for 18 cases with spinal injury before operation, the results were excellent in 9 cases,good in 7,fair in 2. No injury of vertebral artery, nerve root, spinal cord, infection of incisional wound, breaking or loosening of internal fixatir were found in the study.

CONCLUSIONIdentifying the causes of atlantoaxial instability, rational plan of operation can get satisfactory clinical results.