关键词: 3D打印钛笼, 颈前路, 椎体次全切, 减压植骨融合, 疗效分析, 骨科植入物

Abstract: BACKGROUND: As a mainstream surgical technique for the treatment of cervical spondylotic myelopathy through the anterior cervical subtotal decompression and bone graft fusion, it has many advantages. However, due to the high risk of this surgery and the particularity of the cervical anatomy, it is also a challenge for the surgeon. The gradual maturity of 3D printing technology and the continuous development of applications in the medical field are now able to provide more perfect personalized treatment.
OBJECTIVE: To investigate the efficacy of 3D printed titanium cage cutting model in anterior cervical vertebrae subtotal decompression and bone graft fusion. 
METHODS: Medical records of 57 patients undergoing anterior cervical corpectomy decompression and fusion surgery admitted to the Department of Spine Surgery of Affiliated Hospital of Yan’an University from April 2021 to April 2023 were retrospectively analyzed. According to whether the 3D printed titanium cage cutting model was used in the operation, the patients were divided into the traditional titanium cage bone grafting group (control group, n=30) and the 3D printed titanium cage model group (observation group, n=27). The general data, amount of blood loss during operation, number of C-arm X-ray machine fluoroscopy during operation, operation time, as well as anterior intervertebral edge height (H1), posterior intervertebral edge height (H2) and C2-C7 Cobb angle of the two groups measured on the cervical lateral X-ray films before, 3 days and 6 months after operation were recorded and analyzed. The settling degree of the titanium cage was assessed with the distance of the height of the anterior and posterior edges of the vertebral body at 3 days and 6 months after surgery. Visual analog scale was used to evaluate neck pain and Japanese Orthopaedic Association was used to evaluate nerve function. 
RESULTS AND CONCLUSION: (1) Follow-up was conducted for at least 6 months. (2) The amount of intraoperative blood loss and fluoroscopy times in the observation group were less than those in the control group (P < 0.05). The operative time of the observation group was significantly shorter than that of the control group (P < 0.05). (3) There were no significant differences in C2-C7 Cobb angle, visual analog scale score, Japanese Orthopaedic Association score, anterior vertebral border height (H1) and posterior vertebral border height (H2) before surgery, 3 days and 6 months after surgery between the two groups 
(P > 0.05). (4) There were five patients in the observation group (with severe subsidence rate of 19%) with severe subsidence at the anterior and posterior edges of the surgical segment, and seven patients in the control group (with severe subsidence rate of 23%) with severe subsidence (H1 or H2 subsidence ≥3 mm) at the surgical segment 6 months after surgery. There was no significant difference in the rate of severe subsidence of titanium cage between the two groups (P > 0.05). (5) At the last follow-up, bone fusion was achieved at the operative level in both groups, and there was no statistical significance in bone graft fusion rate between the two groups (P > 0.05). (6) The results showed that the application of 3D printed titanium cage cutting model in anterior cervical corpectomy decompression and fusion surgery had the same clinical effect as that of traditional surgery, but the former could effectively reduce the fluoroscopy times of C-arm X-ray machine, the amount of blood loss and the operation time, and had unique advantages in the pruning and implantation of titanium cage during surgery. 

Key words: 3D printing titanium cage,  anterior cervical path,  subtotal vertebral dissection,  decompression bone grafting fusion,  efficacy analysis, orthopedic implants