Is 3D-printed prosthesis stable and economic enough for anterior spinal column reconstruction after spinal tumor resection? A retrospective comparative study between 3D-printed off-the-shelf prosthesis and titanium mesh cage.

Object: To investigate the stability and cost-effectiveness of the three-dimensional-printed (3DP) off-the-shelf (OTS) prosthesis in the reconstruction of the anterior column of the thoracic/lumbar spine after tumor resection. Methods: Thirty-five patients (26 with primary malignant tumors and nine with metastatic malignant tumors) who underwent tumor resection and anterior column reconstruction between January 2014 and January 2019 were included in a single institute. Patients were divided into the 3DP OTS prosthesis (3DP) group (n = 14) and the titanium mesh cage (TMC) group (n = 21) by the type of implant. The operation time, intraoperative blood loss, hospital stay, history of radiotherapy, surgical level and total cost were collected and compared between the two groups. Mechanical complications and radiological parameters including mean vertebral height, subsidence, fixation failure(nonunion, migration, screw loosening, rod breakage) rate were recorded at preoperation, 1 week, 3 months, 6 months, 12 months after surgery then at 1 year interval or stop until the end of survival. The follow-up patients were also sent with short form-36 to assess their health-related quality of life (HRQoL) and questions about the current condition of their disease. Results: The mean overall follow-up was 24.6 months. Of the 35 patients involved, six patients died and six were lost to follow-up. The differences between the two groups in operative time, intraoperative blood loss, and hospital stay were not statistically significant (p > 0.05). The differences in fixation failure and the subsidence rate between the two groups were not statistical significant (p > 0.05). The difference of subsidence rate between the cases with and without osteoporosis, cases with and without radiotherapy was statistically significant within each group (p < 0.05). However, the difference of subsidence rate between the surgical level above or below T10 was not statistically significant (p > 0.05). The response rate of the questionnaire among the survived patients was 100% (23/23 patients). The results of the Short Form- (SF-)36 between the two groups were similar (p > 0.05). The total cost was higher in the 3DP group (p < 0.05) with its higher graft cost (p < 0.05), but the differences in internal fixation cost and other cost were not statistically significant between groups (p > 0.05). Conclusion: Compared to TMC, the 3DP OTS prosthesis achieved similar clinical and radiological results in spinal anterior spinal column reconstruction of thoracic/lumbar spinal tumor resection. However, the 3DP OTS prosthesis was more expansive than TMC. [ABSTRACT FROM AUTHOR]