Realignment of basilar invagination by C1–C2 joint distraction: A modified approach to a paradigm shift

Background: Distraction of the C1–C2 joint and maintenance thereof by introduction of spacers into the articular cavity can successfully and durably reduce basilar invagination (BI). Thus, with the adjunct of instrumented fusion and decompression, BI-induced myelopathy can be efficiently treated with a one-stage posterior approach. This intervention is technically challenging, and in this paper we describe a procedural variation to facilitate the approach. Methods and Results: Through a description of a case of BI, the main anatomopathological alteration underlying and perpetrating the condition of BI is elucidated. A technique of realignment of BI is then described in which this alteration is specifically targeted and neutralized. The result is a single-stage posterior-only approach with decompression, C1–C2 distraction and introduction of poly(methyl methacrylate) (PMMA) into the joint cavity. Instrumented occipitocervical fusion completes the procedure. Conclusion: C1–C2 joint distraction is a technically demanding procedure. By providing a modification of the original technique and a detailed description of the crucial steps necessary to successfully and safely carry it out, we hope to make this excellent procedure more approachable.