Comparative study on the effects of 3D-printed artificial vertebral body and titanium cage in anterior cervical corpectomy and fusion surgery

English Keywords:Cervical spondylotic myelopathy  Anterior cervical corpectomy and fusion  3D-printed artificial vertebral body  Traditional titanium cage  Outcome

English Abstract:

  【Abstract】 Objectives: To evaluate the clinical effects of 3D-printed artificial vertebral body and titanium cage in anterior cervical corpectomy and fusion(ACCF). Methods: A retrospective analysis was performed on 50 patients with cervical spondylotic myelopathy who underwent ACCF of single vertebra in the Spinal Surgery Department of the Affiliated Hospital of Chengde Medical College from June 2017 to June 2020. Among them, 25 patients were treated with 3D-printed artificial vertebral body(observation group) and 25 patients were treated with traditional titanium cage bone grafting(control group). The operative time, intraoperative blood loss, C-arm fluoroscopy times and follow-up period were recorded. Intervertebral height(H1, H2), C2-7 Cobb, C2-7 sagittal vertical axis(C2-7 SVA) and T1 tilt angle of subtotal resection segment were measured on lateral cervical X-ray films before operation, 3 days after surgery, 3 months after surgery and at the last follow-up. The changes of imaging parameters at each time point were compared between the two groups. Neurologic function was evaluated by Japanese Orthopaedic Association(JOA) score and neck pain was evaluated by visual analogue scale(VAS). Bone graft fusion was evaluated according to Kandziora criteria. Results: All patients were followed up for 12 to 33 months, averaged 24.16±4.95 months(observation group) and 22.60±5.91 months(control group) with no statistical difference between the two groups(P>0.05). There were no significant differences in operative time, intraoperative blood loss and C-arm fluoroscopy frequency between the 2 groups(P>0.05). The JOA score and VAS score of both groups at each time point after surgery were significantly improved compared with those before surgery, with statistical significance(P<0.05), but there was no statistical difference between the two groups at the same time point(P>0.05). Intervertebral height, C2-7 Cobb, C2-7 SVA and T1 tilt angle of the 2 groups at each time point after surgery were significantly improved compared with those before surgery(P<0.05), there were no significant differences between the 2 groups before surgery and at 3 days after surgery(P>0.05), and there were statistical differences between the 2 groups at 3 months after surgery and the last follow-up(P<0.05). At the last follow-up, there was sinking of the artificial vertebral body in 19 patients of the observation group, with a sinking distance of 0.1-0.9mm, and none occurred serious sinking. In the control group, 20 cases occurred titanium cage subsidence at a sinking distance of 1.3-3.5mm, and 4 cases sank seriously. The sinking distance of the artificial vertebral body in the observation group was less than that in the control group, and the difference was statistically significant(P<0.05). Bone fusion was achieved in all patients at the last follow-up. Conclusions: In ACCF surgery for patients with cervical spondylotic myelopathy, both 3D-printed artificial vertebral body and traditional titanium cage bone grafting can restore the intervertebral height, reconstruct the cervical stability and cervical physiological curvature. The 3D-printed artificial vertebra can slow down the settlement of the postoperatively supported prosthesis, thus maintaining the height between the decompressed vertebrae and the physiological curvature of the cervical spine.