Surgical Treatment Of Atlantoaxial Instability

ObjectiveTo retrospectively analyse the surgical method and its clinical effectiveness for atlantoaxial instability and evaluate surgical options for different types.MethodsSixty one patients with atlantoaxial instability were surgical treated at the authors'clinic from December 2007 to August 2010. There were 32 males and 29 females and the average age was 38 years old (range,12-68years old). There were 10 patients with unstable odontiod fracture,6 cases with odontoid deformity and os odontiodeum,27 cases with atlantoaxial dislocation,20 cases with sub luxation. The causes include:trauma in 12 cases, inflammatory arthropathy in 3 cases, congenital developmental malformation in 38 cases, and etiology unknown in 8 cases. Patients were treated by different surgical approaches,5 cases by external fixation with Halo-vest,5 cases by anterior fixation of the dens fractue with a cannulate screw,23 cases by posterior C1-C2 fusion,28 cases by occipitocervical fusion. The preoperative and postoperative Japanese Orthopaedic Association (JOA) scores were adopted to evaluate neural functions and medical imaging examination was taken to evaluate bone fusion.ResultsAll the Sixty one patients were followed up for an average of 19.6 months range,10 days to 36mnths). One patient died of multiple organ dysfunction syndrome 10 days after surgery, the other 60 patients were followed up from 3 to 36 months. Solid union was obtained in 60 cases with delayed union among them. The symptoms subsided in 37cases, significantly improved in 11 cases, slightly improved in 2 cases. JOA score improved with the average of 5.54, the total improvement rate was 0.76. Obvious limitation of rotative activity were founed in all 51 patients with posterior internal fixation. No such complications as injury to vertebral artery and spinal cord were met in all patients. There were one case had cerebrospinal leak and one with incision fat liquefy. No migration, loosening and breakage of internal fixators were founded in all patients.ConclusionSelection of surgical method mainly depends on causes and types of atlantoaxial instability and the result of traction reduction to achive atlantoaxial stability and preserve the upper cervical spine function as more as possible. According to this principle, appropriate surgery and treatment strategies could be selected, and satisfactory treatment effectiveness could be obtained.