Treatment of benign tumors in thoracic spinal canal by modified replanting posterior ligament complex applying piezoelectric osteotomy

Yuwei LI

ABSTRACT

Objective: To investigate the feasibility and effectiveness of modified replanting posterior ligament complex (PLC) applying piezoelectric osteotomy in the treatment of primary benign tumors in thoracic spinal canal. Methods: The clinical data of 38 patients with primary benign tumors in thoracic spinal canal between March 2014 and March 2016 were retrospectively analyzed. There were 16 males and 22 females, aged from 21 to 72 years (mean, 47.1 years). The disease duration ranged from 6 to 57 months (mean, 32.6 months). Pathological examination showed 24 cases of schwannoma, 6 cases of meningioma, 4 cases of ependymoma, 2 cases of lipoma, and 2 cases of dermoid cyst. The lesions located in 18 cases of single segment, 15 cases of double segments, and 5 cases of three segments. The length of the tumors ranged from 0.7 to 6.5 cm. There were boundaries between the tumors and the spinal cord, cauda equina, and nerve roots. The preoperative Japanese Orthopaedic Association (JOA) score was 12.2±2.3 and the thoracic Cobb angle was (11.7±2.7)°. Modified PLC replantation and microsurgical resection were performed with piezoelectric osteotomy. Continuity of uniside supraspinal and interspinous ligaments were preserved during the operation. The PLC was exposed laterally. After removing the tumors under the microscope, the pedicled PLC was replanted in situ and fixed with bilateral micro-reconstruction titanium plate. X-ray film, CT, and MRI examinations were performed to observe spinal stability, spinal canal plasty, and tumor resection after operation. The effectiveness was evaluated by JOA score. Results: The operation time was 56-142 minutes (mean, 77.1 minutes). The intraoperative blood loss was 110-370 mL (mean, 217.2 mL). The tumors were removed completely and the incisions healed well. Three cases complicated with cerebrospinal fluid leakage, and there was no complications such as spinal cord injury and infection. All the 38 patients were followed up 24-28 months (mean, 27.2 months). There was no internal fixation loosening, malposition, or other related complications. At last follow-up, X-ray films showed no sign of kyphosis and instability. CT showed no displacement of vertebral lamina and reduction of secondary spinal canal volume, and vertebral lamina healed well. MRI showed no recurrence of tumors. At last follow-up, the thoracic Cobb angle was (12.3±4.1)°, showing no significant difference when compared with preoperative value ( t=0.753, P=0.456). JOA score increased to 23.7±3.8, showing significant difference when compared with preoperative value ( t=15.960, P=0.000). Among them, 14 cases were excellent, 18 were good, 6 were fair, and the excellent and good rate was 84.2%. Conclusion: Modified replanting PLC applying piezoelectric osteotomy and micro-reconstruction with titanium plate for the primary benign tumors in thoracic spinal canal can reconstruct the anatomy of the spinal canal, enable patients to recover daily activities quickly. It is an effective and safe treatment.