Abstract: Objective　To compare the effects of two fixation methods on changes of cervical sagittal parameters in patients after short segment of anterior cervical discectomy and fusion (ACDF). Methods　A restrospective analysis was performed on 59 patients with cervical spondylotic myelopathy and/or cervical spondylotic radiculopathy with short segment of ACDF in Department 1 of Spine Surgery, Tianjin Union Medical Hospital from September 2017 to January 2019. There were 31 males and 28 females in these patients, aged 23-71 years old, average (47.17±11.95) years, and follow-up time was 6-25 months, average 12 (7, 15) months. Patients were divided into titanium plate allied with cage group (titanium plate group, n=39) and ROI-C group (ROI-C group, n=20) according to the fixation methods. The patients were routinely examined with cervical X-rays, CT and MRI prior to surgery. Postoperative follow-up continued at least 6 months. The frontal and lateral cervical X-rays were performed at the follow-up, CT and MRI were also performed when necessary. Both preoperative and follow-up cervical sagittal parameters were measured through X-ray films, including C2-C7 Cobb angle (Cobb angle), C2-C7 sagittal vertical axis (C2-C7 SVA) and segment Cobb angle (SCobb angle). The differences of corresponding cervical sagittal parameters measured preoperatively and at final follow-up were calculated, including ΔCobb angle (the difference value of C2-C7 Cobb angle before operation and at last follow-up), ΔC2-C7 SVA (the difference value of C2-C7 SVA before operation and at last follow-up) and ΔSCobb angle (the different value of segment Cobb angle before operation and at last follow-up). The differences of above indicators were compared between two groups. Results　There were no significant differences in age, gender, operation time, bleeding volume and operative level between the two groups. The final follow-up Cobb angle and SCobb angle were significantly increased after operation in titanium plate group, and the C2-C7 SVA significantly decreased compared with those before operation. In ROI-C group, SCobb angle was significantly increased at the last follow-up. There were no significant differences in preoperative and final follow-up Cobb angle, C2-C7 SVA and SCobb angle between the two groups. There were no significant differences in ΔCobb angle          and ΔC2-C7 SVA between the two groups. However, the ΔSCobb angle was statistically higher in the titanium plate group than that in the ROI-C group. Conclusion　Both short segment of ACDF with either titanium plate + Cage or ROI-C fixation method can effectively correct the lordosis of the cervical spine, but the titanium plate group has better operation segment cervical lordosis in the recovery. For the choice of surgical methods, surgical complications should also be taken into account.

Key words: discectomy, spinal fusion, cervical spondylosis, cervical lordosis, cervical sagittal parameters