Combined open and minimally invasive strategy for thoracic ossification of posterior longitudinal ligament: a case report and technical notes

Introduction and importance: Thoracic ossification of the posterior longitudinal ligament (T-OPLL) causes severe neurological deficits. Surgical management is challenging due to the thoracic spine's anatomical complexity. This case report aims to describe a novel hybrid open-endoscopic technique for the treatment of severe thoracic OPLL, with the objective of demonstrating its feasibility and safety in a high-risk obese patient. Presentation of case: A 29-year-old male with class III obesity was hospitalized for progressive bilateral lower extremity weakness over 2 months, recently worsening with new-onset numbness. Examination revealed hypoesthesia below the costal margin, decreased lower extremity motor strength, and reduced anal tone. Imaging showed T-OPLL at T5/6 with significant spinal cord compression and stenosis. Complete 360° decompression was achieved via posterior open laminectomy using an ultrasonic bone scalpel, combined with ventral decompression via minimally invasive endoscopy. The patient had satisfactory outcomes without complications. Clinical discussion: The full endoscopic transforaminal approach has been successfully used in ventral thoracic spinal cord compression. However, due to the narrow spinal canal and small intervertebral foramina in the thoracic region, the limited operational space during cannula placement and removal of ventral ossified lesions still leads to complications. To address this, we first performed a total laminectomy in this case to achieve indirect dorsal decompression, followed by foraminotomy under direct visualization. This preparatory step created sufficient working space for subsequent cannula insertion and ventral decompression, minimizing spinal cord manipulation and effectively reducing iatrogenic spinal cord injury. Conclusion: This study introduces a combined surgical approach. Integrating open and minimally invasive endoscopic techniques achieves comprehensive 360° decompression while minimizing trauma and complications. This hybrid technique is an alternative for severe thoracic spinal stenosis primarily from ventral compression.