A novel posterior decompression technique (anterior sliding decompression osteotomy) for beak-type ossification of the posterior longitudinal ligament in the thoracic spine

OBJECTIVE Conventional decompression surgery for beak-type ossification of the posterior longitudinal ligament (OPLL) of the thoracic spine, whether approached anteriorly or posteriorly, poses several challenges, including technical complexity, cerebrospinal fluid leakage, incomplete decompression, and potential neurological deterioration. Therefore, the authors introduce a novel technique, anterior sliding decompression osteotomy (ASDO), for thoracic myelopathy caused by OPLL and evaluate the efficacy and safety of this technique. METHODS Six patients (4 men and 2 women) who underwent ASDO surgery for beak-type OPLL in the thoracic spine with a follow-up period of at least 2 years were included in the cohort. Clinical and surgical outcomes, including modified Japanese Orthopaedic Association (mJOA) score, neurological recovery rate, canal occupying ratio, operation time, and blood loss, were evaluated. RESULTS The mean ± SD follow-up period was 26.5 ± 2.0 months. The mean mJOA score improved from 6.0 to 9.7, with the mean recovery rate reaching 63.6% at 6 weeks postoperatively to 73.9% at 2 years after surgery. Neural decompression was effective in all patients, reducing the mean canal occupying ratio from 70.8% to 29.1% without complications. CONCLUSIONS ASDO surgery achieves sufficient spinal cord decompression for beak-type OPLL in the thoracic spine. It represents an effective, feasible technique, offering surgeons a familiar view from the conventional posterior approach.