Posterior circumferential decompression for multilevel thoracic ossification of the posterior longitudinal ligament: a case report and literature review.

Multilevel thoracic ossification of the posterior longitudinal ligament (T-OPLL), especially when it involves more than five consecutive vertebrae, remains surgically challenging. In recent years, a strategy focused on "spinal cord de-tension" has been proposed for such extensive involvements. This report describes a 52-year-old woman who presented with progressive thoracic myelopathy due to continuous OPLL from T3 to T10, causing severe canal stenosis. The surgical approach included a posterior laminectomy from T4 to T10, circumferential decompression at the most compressed level (T8-9), and long-segment instrumentation from T3 to T11. A postoperative cerebrospinal fluid leak was suspected but managed conservatively with controlled drainage and bed rest. By the 12-month follow-up, the patient's neurological status had improved markedly: her modified Japanese Orthopaedic Association (mJOA) score rose from 5 to 10, corresponding to a Hirabayashi recovery rate of 83.3%. Radiographs showed adequate decompression, solid fusion, and no implant failure. Taken together, for symptomatic, ultra-long segment T-OPLL, posterior circumferential decompression combined with long-segment fusion under the spinal cord de-tension principle appears to be highly effective. Spinal shortening achieved through parallel osteotomy and compression provides indirect longitudinal de-tension, complementing direct ventral decompression while maintaining stability. Careful surgical technique and systematic management of complications like cerebrospinal fluid leakage remain essential for a good outcome. This approach offers a favorable risk-benefit balance in these complex cases.