Role of C1-2 Facet Distraction in Treating Basilar Invagination: A Meta-Analysis

Introduction: The surgical management of basilar invagination with anterior transoral odontoidectomy followed by posterior cervical fixation or posterior foramen magnum decompression carries high morbidity and mortality. The Goel's technique with C1-2 facet distraction has offered indirect ventral brain stem decompression via vertical reduction of basilar invagination. Such technique has gained popularity over the past decade. In this study, we aim to evaluate the safety and efficacy of C1-2 facet distraction in reduction of basilar invagination.

Methods: With adherence to PRISMA guideline, comprehensive database searches were conducted to identify studies that evaluate C1-2 facet distraction for reduction of basilar invagination. Various clinical and radiographic outcome parameters were assessed. Independent reviewers extracted data and assessed the outcome. A meta-analysis using random effect weight mean difference model (WMD) was constructed.

Results: A total of 9 studies comprising of 218 patients underwent C1-2 distraction and fixation for basilar invagination. The most common cage material used was PEEK along with autologous bone grafts. Approximately, 9.2% of patients did not require occipital fixation. The most common reasons for occipital fixation was due to occipital assimilation and for cantilevel reduction. There was marked improvement of neurological functions with mean postop JOA of 14.8 ± 1.0. The mean postoperative distance from the odontoid tip improved to 5.0 ± 4.1mm. Other radiological parameters such as ADI and clival canal angle have also improved postoperatively. 1 patient had incidental vertebral artery injury that did not lead to neurological damange.

Conclusion : In conclusion, atlantoaxial distraction and fixation offer safe and lower morbid approach to treat basilar invagination of various etiologies.