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IntroductionThoracic ossification of the ligamentum flavum (TOLF) is a common cause of progressive thoracic myelopathy. Surgical decompression is commonly used to treat TOLF.AimTo evaluate the clinical outcomes of microsurgical decompression of TOLF via a paraspinal approach, using a percutaneous tubular retractor system.Material and methodsFirst, three-dimensional (3D) image reconstruction and printed models were made from thin computed tomography scans for each patient. Then, 3D computer-assisted virtual surgery was performed using the 3D reconstruction to calculate the precise location and sizes of the bone window and the angle of insertion of the percutaneous tubular retractor system. In total, 13 patients underwent the surgery through the percutaneous micro channel unilateral vertebral approach under electrophysiological monitoring. Five days after the surgery, increased creatine phosphokinase levels returned to preoperative levels. The Japanese Orthopedic Association (JOA) score was improved and computed tomography reconstruction and magnetic resonance imaging of the thoracic spine showed that decompression was achieved without injuries to the spinal cord or nerve root. The stability of the spine was not affected, nor were any deformities of the spine detected. Finally, nerve functional recovery was achieved with minimal injury to the paraspinal muscle, articulum, spinous process and ligament.ResultsThe mean operative time was 98.23 ±19.10 min, and mean blood loss was 19.77 ±5.97 ml. At a mean follow-up of 13.3 months (median: 12 months), the mean JOA score was 7.54 ±1.13 at the final follow-up, yielding a mean RR of 49.10 ±15.71%. Using The recovery rate, 7 (53.85%) patients had good outcomes, 5 (38.46%) patients had a fair outcome, and 1 (7.69%) patient had poor outcomes, indicating significant improvement by the final follow-up examination (p < 0.05).ConclusionsThe 3D printed patient model-based microsurgical resection of TOLF via the paraspinal approach can achieve decompression of the spinal canal with minimal complications, faster recovery and improved stability of the vertebral body.

The aim of the present study was to investigate the efficacy of combining paraspinal keyhole surgery with a tubular retractor system for the microsurgical removal of lumbar intraspinal extramedullary schwannomas. A retrospective analysis was conducted of 56 patients with lumbar intraspinal extramedullary schwannomas who were treated using the microsurgical paraspinal keyhole approach with a tubular retractor system. The mean ± standard deviation was calculated for the following parameters: Surgery time (96.21±14.64 min), hemorrhagic volume (28.54±9.72 ml), bed rest (2.55±0.5 days) and hospital stay (5.68±0.72 days). Two patients presented with cerebrospinal fluid leakage and one patient exhibited a nerve root injury. At a 6-month follow-up visit, postoperative Japanese Orthopedic Association (JOA) and visual analog scale (VAS) scores were evaluated. The mean ± standard deviation JOA scores were 12.00±2.07 for preoperative, 14.73±2.05 for 1 week postoperative, 20.07±2.32 for 3 months postoperative and 21.75±2.18 for 6 months postoperative. The improvement rate was 16.07, 47.48 and 59.77%, respectively. The mean ± standard deviation VAS scores were 6.64±1.31 for preoperative, 3.82±1.51 for 1 week postoperative, 2.11±1.17 for 3 months postoperative and 1.50±1.51 for 6 months postoperative. The JOA and VAS scores improved significantly (P<0.05). Magnetic resonance imaging and computed tomography were performed preoperatively, immediately following surgery and at the 6-month postoperative visit to confirm the efficacy of the resections and evaluate spinal stability. No residual tumors were identified at follow-up. No alterations in the stability of the spine were observed postoperatively. The combination of the microsurgical paraspinal keyhole approach with the tubular retractor system was successful in treating lumbar intraspinal extramedullary schwannomas. The surgical approach was associated with decreased hemorrhages, decreased duration of hospital stay, faster recovery and improved postoperative maintenance of spinal stability.