Purpose: Revision surgery in an irreducible atlantoaxial dislocation (IAAD) previously operated with a posterior approach is challenging. Multiple modalities using anterior, posterior, and dual approaches have been described. We report a so far unreported technique of revision surgery by posterior implant removal and decompression with anterior transoral release followed by posterior instrumentation.

Methods: 14-year male with basilar invagination (BI) with IAAD, previously operated with posterior decompression and instrumented occipitocervical fusion presented three months later with post-traumatic recurrence of myelopathy with quadriparesis with Di Lorenzo grade 4 and loss of reduction. He was operated with a posterior implant and early fusion mass removal with extended foramen magnum decompression (FMD), followed by anterior transoral release with a satisfactory reduction on traction, and finally, a posterior revision instrumented occipitocervical fusion.

Results: At 2-year follow-up, the patient was symptom-free with Di Lorenzo grade 1 and cervicomedullary angle improvement from 97.4° to 141.2°; achieving bony fusion.

Conclusion: Single-stage posterior-anterior transoral-posterior approach can be used to achieve satisfactory reduction for a revision BI with IAAD with prior posterior instrumentation.