The effect of 3D printed individualized artificial vertebra on spinal stability reconstruction after multi-level spinal tumor resection: an exploratory clinical study

English Keywords:Spinal tumor  3D printing  Multilevel vertebrectomy  Artificial vertebral body

English Abstract:

  【Abstract】 Objectives: To investigate the safety and effectiveness of 3D printed individualized artificial vertebra on spinal stability reconstruction after multi-level spinal tumor resection. Methods: From May 2017 to December 2019, 9 patients who underwent multi-level total vertebrectomy and spinal reconstruction using individualized 3D printed artificial vertebralbody were analyzed retrospectively. There were 3 males and 6 females, with a mean age of 41.7±10.5 years(range, 20-57). 9 primary tumors were included. Based on the tumor location and surrounding soft tissue invasion range, posterior approach(8 cases) and combined anterior and posterior approach(1 case) were adopted for total vertebral resection, with 3D printed artificial vertebral body for reconstruction. The mean follow-up period was 18.3±11.4 months(range, 6-36 months). The operation time, intraoperative bleeding volume, postoperative stability of artificial vertebral body and bone ingrowth of adjacent vertebral body, preoperative and postoperative neurological changes, preoperative and postoperative VAS score, local control, metastasis and survival of patients were collected and analyzed. Meanwhile, according to Brantigan & Steffee classification of spinal fusion, X-ray(1 month, 3 months, 6 months, 12 months, and every 6 month) and CT(6 months, 12 months, 24 months, and every 6 month) were used to evaluate the stability of artificial vertebral body and bone fusion during the follow-up. Results: All 9 patients were successfully treated with 3D printed artificial vertebral body reconstruction, among them 4 cases underwent 2 levels vertebrectomy and 5 cases underwent 3 levels vertebrectomy. The mean operation time was 433.3 minutes(range, 235-740 minutes), and the mean blood loss was 4816.7ml(range, 1000-14000ml). Compared to the preoperative VAS score(4.1±1.1), the score at 7 days postoperative(1.2±0.4) was significantly reduced(P<0.001). At 7 days postoperatively, for the 3 patients of Frankel grade D before operation, except 1 with no obvious change, the other 2 gradually recovered to grade E, and no obvious change was found in 6 grade E patients. During the follow-up, there was no loosening or displacement of the artificial vertebral body and no failure of internal fixation. Preliminary bone growth was found between the artificial vertebral body and the adjacent vertebral body 6 months after operation. The bone growth was more obvious at 12 months postoperatively, and the artificial vertebral body was fused with the adjacent vertebral bodies to form bone integration. There was no tumor recurrence and metastasis in 7 patients. One patient with chondrosarcoma developed local recurrence at 16 months after operation. A case of epithelioid angiosarcoma died at 18 months postoperatively. The median survival time was 18 months. Conclusions: 3D printed individualized artificial vertebral body can meet the requirements of spinal stability reconstruction after resection of multi-level spinal tumors. It can effectively restore the continuity of the spine, and precisely match the adjacent vertebral bodies. In addition, its own pore structure is conducive to bone growth. Therefore, it is an ideal spinal reconstruction method after multi-level spinal tumor resection.