A modified microsurgical interfacet release and direct distraction technique for management of congenital atlantoaxial dislocation: technical note.

Various techniques have been used for management of congenital atlantoaxial dislocation. Recently, the reduction of atlantoaxial dislocation through a single posterior approach has attracted more and more attention. Here, we present a modified technique including direct interfacet release and distraction between C1 and C2 by a specially designed distractor, posterior internal fixation and bone graft fusion. The illustrated technique was performed in 15 consecutive patients, and the outcomes were recorded and analyzed. Follow-up ranged from 12 to 26 months. Clinical symptoms improved in 14 patients (93.3%) and were stable in 1 patient (6.7%). Radiologically, 60-100% reduction was achieved in 13 patients (86.6%). Bone fusion was obtained in all patients at 12 months after the operation. The two-tailed Wilcoxon signed-rank test was used to analyze the preoperative and postoperative Japanese Orthopedic Association scores (JOA), atlas-dens interval (ADI), and cervicomedullary angle (CMA) (P < 0.001). Our results suggested that this direct interfacet release and distraction technique with a specially designed C1-2 distractor can provide a definite effective C1-2 facet distraction and odontoid process restoration through a single posterior approach.