Percutaneous Endoscopic Posterior Decompression for Therapy of Spinal Cord Compression Due to Ossification of the Ligamentum Flavum: A Long-Term Follow-up

Abstract

Thoracic ossification of the ligamentum flavum (OLF) is a pathologic condition that affects ligamentation of the OLF and causes slowly progressive myeloradiculopathy. There is a trend toward performing minimally invasive surgery. In this study, we assess the long-term efficacy of percutaneous endoscopic surgical management of thoracic OLF. Twenty patients with thoracic myelopathy due to thoracic OLF underwent percutaneous endoscopic surgical management. We investigated clinical outcomes and neurologic improvements. Magnetic resonance imaging was performed on all patients preoperatively and postoperatively, and intramedullary signal changes were evaluated. The operation time averaged at 170.4 minutes (range 110-320 minutes). The mean intraoperative blood loss was 29.6 mL (range 5-100 mL). Cerebrospinal fluid leakage occurred in 1 patient and healed well. The follow-up period ranged from 60 to 72 months. The mean score on the Japanese Orthopedic Association scale improved from (6.0 ± 1.41) preoperatively to (7.83 ± 1.40) at 1 month postoperatively to (9.67 ± 1.30) at the final follow-up (P<0.05). At the final follow-up stage, 11 patients had excellent outcomes, 6 good, 2 fair, and 1 unchanged, according to the Hirabayashi recovery rate. No patient had postoperative deterioration in neurologic status. Percutaneous endoscopic surgical management of thoracic OLF has proven to be both safe andeffective for the resection of the OLF in the thoracic spine.