Application of three-dimensional visualization technology in surgical resection of thoracic ossification of ligamentum flavum

Abstract

Objective To evaluate the for thoracic ossification of the ligamentum flavum (OLF) by preoperative planning of preoperative three-dimensional visualization. Methods From November 2013 to December 2016, forty-four patients (25 males, 19 females, 40-76 years old) with thoracic OLF underwent preoperative three-dimensional (3D) visualization surgery planning. The three-dimensional structure of OLF were reconstructed with digital imaging, and the positional relationship with pedicle, articular process and lamina were displayed. The numerical simulation of osseointegration volume were calculated. We performed a simulated resection of the OLF on a 3D visualization digital model by Zoning laminectomy . Duration of operation, volume of bleeding, complication were recorded. The neurological function of the patients was evaluated by the Japan Orthopaedic Association (JOA) spinal function scale and calculated the improvement rate. Results The 44 preoperative three-dimensional reconstruction models were used to simulate surgical resection. The volume of digital simulation single OLF was (1 831±443)mm3. The average operating duration was 65-180(96.7±19.6)min, the average bleeding was 230-1 350(432±83.5)mL . The symptoms of spinal cord nerve injury did not increase after operation. The neurological symptoms of the patients were gradually improved after surgery. Forty-four patients were followed up after surgery. Follow-up time was 13-46 (25±10.3) months. No complications, such as delayed infection, aggravation of neurological symptoms and failure of internal fixation, occurred during follow-up. JOA score was 8.8±1.8 at 12 months after surgery, which was significantly higher than that before surgery 5.3±2.0, and the difference was statistically significant (t=11.566, P<0.01). JOA score improvement rate was 64.2%±21.7%. The curative effect evaluation was excellent in 13 cases, good in 21 cases, and fair in 10 cases, with the excellent and good rate of 77.3% (34/44). Conclusions The preoperative evaluation is performed using 3d visualization technology, and the morphology of ossified ligament flavum can be understood stereoscopic and comprehensively. The surgical resection area is designed by simulating the operation. It can improve surgical accuracy, safety and effectiveness. It provides a new preoperative imaging assistant method for the diagnosis and treatment of ossification of thoracic vertebra ligament yellow. Key words: Ligamentum flavum; Ossification, heterotopic; Thoracic vertebrae; Imaging, three-dimensional; Laminectomy; Preoperative planning