Clinical effectiveness of percutaneous endoscopic spinal surgery via transforaminal approach for single-level thoracic ossification of the posterior longitudinal ligament

Abstract Background Percutaneous endoscopic spinal surgery (PESS) was performed for a series of cases with single-level thoracic ossification of the posterior longitudinal ligament (T-OPLL). This study was to evaluate the clinical feasibility and effectiveness of percutaneous endoscopic spinal surgery via a transforaminal approach for T-OPLL. Methods 15 patients with thoracic single-level ossification of the posterior longitudinal ligament (T-OPLL) were admitted to our hospital from October 2016 to October 2019 and treated with percutaneous endoscopic spinal surgery via transforaminal approach. There were 7 males and 8 females with an average age of (56.4 ± 8.4) years (range: 41 to 71 years). Computed tomography (CT) with 3-dimensional reconstruction and magnetic resonance imaging (MRI) were used to confirm the vertebral level of T-OPLL. Levels of T-OPLL: T7/T8 in 1 case, T9/T10 in 2 cases, T10/T11 in 6 cases, T11/T12 in 4 cases, and T12/L1 in 2 cases. The surgical index, neurological function, and clinical results were recorded in this study. Results All surgeries were successfully completed without any conversion to open surgery, no severe intraoperative complications such as dural sac tear, major vessel or spinal cord injury were reported in our study. The average operation time was 79.1 ± 29.4 min (ranged, 43 to 132 min). The amount of intraoperative blood loss was 62.3 ± 20.8 mL. The lengths of postoperative hospital stays were 4.1 ± 1.1 days. The follow-up rate was 93.3% (14/15). The follow-up time ranged from 13 to 32 months (mean, 20.3 ± 6.3 months). the satisfactory decompression was confirmed by the CT and MRI. The Visual Analog Scale (VAS) score improved from 5.9 ± 0.7 preoperatively to 2.1 ± 0.9 at the last follow-up ( P < 0.001), and Oswestry Disability Index (ODI) improved from 46.9 ± 4.5 preoperatively to 9.9 ± 8.0 at the last follow-up ( P < 0.001). Neurological function was evaluated by Japanese Orthopedic Association 29 (JOA29) score, which significantly improved from 16.0 ± 1.9 to 21.2 ± 1.1 ( P < 0.0001). The good and excellent rates were 71.4% according to the modified MacNab criteria. No revision surgery was performed because of the residual nucleus pulposus or recurrent disc herniation. Conclusion As a minimally invasive spinal technique, PESS is a clinically feasible, safe and effective alternative approach to conventional procedures in the treatment of single-level T-OPLL.