Application of 3D printed porous artificial vertebra in reconstruction of thoracolumbar tumor

Objective To evaluate the clinical effectiveness of the reconstruction of the thoracic and lumbar spine using the 3D-printed vertebral body after total en bloc spondylectomy. Methods From December 2016 to September 2019, 33 patients with spinal tumors were treated with total en bloc spondylectomy, including 25 males and 8 females with an average age of 58.0 years(range, 15 to 76). The locations of the lesions contained: 29 in the thoracic and 4 in the lumbar. The surgical segments includeda single vertebra in 30 cases, 2 vertebrae in 2 cases, and 3 vertebrae in 1 case. The tumor type: the primary malignant tumor in 6 cases, the metastatic tumor in 27 cases. The preoperative Tomita score was 2-5 points (mean 3.9 points), while Tokuhashi score was 9-15 points (average 11.1 points). Divided into two groups according to different reconstruction methods during total spinal resection, 33 patients with thoracolumbar vertebral body malignant tumors were divided into 3D printed artificial vertebral body reconstruction group (21 patients, 3D printed artificial vertebral body was used for anterior column reconstruction) and titanium Mesh reconstruction group (12 cases, titanium mesh implanted with allograft bone was used for reconstruction). The main observation indicators included the degree of spinal nerve damage and pain recovery, the local tumor control rate, and the incidence of prosthesis sinking. The visual analogue scale (VAS) at 24 hours and 3 months after operation was compared with that before operation using paired design t test. Results All cases were followed up for 3 to 31 months. There was no statistically significant difference in intraoperative blood loss (t=2.042, P>0.05), surgical time (t=0.591, P>0.05), and postoperative drainage (t=0.118, P>0.05) between the two groups. The visual analogue scale (VAS) between the two groups at preoperative, 24 hours and 3 months after operation was not statistically different (P<0.05). The Frankel grading of 31 patients (97.0%) had at least one grade improvement 3 months after operation. During the follow-up period, 12 patients (41.7%) who underwent reconstruction with titanium mesh showed different degrees of subsidence in imaging, and 21 patients who used 3D printed artificial vertebral reconstruction did not exhibit prosthetic deposition. Chi-square test results of postoperative sink rate of the two methods was statistically different (χ2=10.313, P=0.013). Conclusion This preliminary report suggests the 3D-printed vertebral body has good biocompatibility and mechanical stability, which can be used for reconstruction after total en bloc spondylectomy. Key words: Spinal neoplasms; Spinal fusion; Prostheses and implants