Comprehensive Drilling of C1-2 Facets and Multiplanar Realignment for Atlanto-Axial Dislocation and Basilar Invagination: 2-Dimensional Operative Video

Abstract The management for congenital atlantoaxial dislocation (AAD) and basilar invagination (BI) has significantly changed in the last 2 decades. Authors operate these cases through a direct posterior approach by opening and manipulating the C1-2 joints (irrespective of C1 assimilation), modifying Goel's technique. The joints in these cases are often oblique in both sagittal and coronal planes giving rise to anteroposterior and vertical slip of C1 on C2. Asymmetry on either side gives rise to coronal/lateral angular tilt along with rotational component. The authors have described comprehensive drilling of the facets (osteotomies) in sagittal and coronal planes to release the joints. Metallic spacers with graft window packed with bone chips are inserted to compensate for the drilled bone. Screws are inserted in C1 lateral mass and C2 pedicle. A rod is fastened between the screw heads and further multiplanar realignment can be achieved by manipulating the rod. The technique obviates the need for transoral decompression and the C1-2 joints are closely fused. The facetal osteotomies coupled with manipulation for realignment in all planes provides a composite solution for even the extremely complex lateral dislocation or complete spondyloptosis with severely deformed C1-2 joints that may be difficult with techniques described earlier. There is no need to include occipital squama and multiple cervical vertebrae in the construct, irrespective of the C1 assimilation. The authors have operated over 200 cases of irreducible CAAD/BI with good outcome and have illustrated their technique in this video. Proper informed consent was obtained from the patient.