3D printing technology assisted the preoperative planning and application value in adult kyphoscoliosis deformity

Abstract

To explore the application value of 3D printing technology in preoperative surgery plan and intraoperative auxiliary operation for adult kyphoscoliosis deformity. The clinical data of 12 adult patients with kyphoscoliosis deformity treated from September 2017 to January 2019 were retrospectively analyzed. There were 3 males and 9 females, aged from 21 to 63 years old with an average of (47.67±13.32) years old. Among them, 4 cases were congenital kyphoscoliosis, 2 cases were old tuberculosis thoracolumbar kyphosis ; 2 cases were idiopathic kyphoscoliosis, 4 cases were degenerative kyphoscoliosis. The CT scan data of the patient's spine was imported into Mimics17.0 software to establish the three dimensional model of the spine, and the spine model was produced by 3D printer. Using the spine model simulated operation, preoperative surgery program planning and formulated a precise surgery, and further analysed postoperative imaging parameters improvement. All the patients were followed up for more than 1 year. Before and after operation and at the last follow-up, the scoliosis Cobb angle, maximum kyphosis Cobb angle, and coronal plane balance (distance between C 7 plumbline and center sacral vertical line, C7PL-CSVL), sagittal plane balance (sagittal vertical axis, SVA), pelvic parameters and other related imaging parameters were measured to further evaluate its orthopedic effect. Twelve patients with spine deformity were treated with different osteotomy and internal fixation fusion methods under the guidance of a 1∶1 spine model (pedicle screw placement of 4 patients with severe deformity were assisted by pedicle screw guide plates), nail placement and osteotomy have good effects, no major tissue damage such as blood vessels, nerves and spinal cord during and after surgery, no complications such as cerebrospinal fluid leakage and infection. Preoperative Cobb angle of scoliosis was (56.5±22.5) °, Cobb angle of kyphosis was (65.2±19.5) °, C7 PL-CSVL was (45.8±16.9) mm, SVA was (48.7±25.4) mm. Postoperative at 4 weeks, Cobb angle of scoliosis was (20.8±11.5) °, and Cobb angle of kyphosis was (22.0±6.6) °, with correction rates of (65.1±9.7)% and (64.6± 10.6)%, respectively ; C7 PL-CSVL was (22.3±8.9) mm, and SVA was (23.3±13.1) mm, all of which were significantly improved compared with preoperative results. The mean follow-up time was (18.5±7.9) months in 12 patients. At the last follow-up, the Cobb angles of scoliosis and kyphosis were (22.2±10.8) ° and (23.6±7.7) °, respectively, C7 PL-CSVL was (23.5±10.8) mm, and SVA was (24.7±12.5) mm. The results were statistically significant compared preoperative (P<0.05). There was no significant difference at the postoperative at 4 weeks and the last follow-up (P>0.05). The 3D print model can visually and clearly show the vertebral morphology and structure of adult kyphoscolisis and its spatial relationship with the adjacent vertebrae, blood vessels, and nerves, which provides a good and intuitive stereoscopic anatomical structure observation for the individualization of the surgical plan. Pre-simulation of operations to determine the internal fixation, fusion segment and osteotomy orthopedic way, may to provide a reference for actual clinical surgery, and can improve the accuracy and safety of surgery.