Correlation analysis between C 7 slope and cervical sagittal parameters in short segment anterior cervical discectomy with fusion

目的: 通过影像学测量探讨短节段颈前路椎间盘切除融合术（anterior cervical discectomy with fusion，ACDF）中术前 C 7 倾斜角（C 7 slope，C 7S）与颈椎矢状位参数变化的关系。. Methods: A retrospective analysis of 54 patients (24 males and 30 females) with ACDF for cervical spondylosis between January 2012 and January 2017 was performed. The age ranged from 23 to 71 years (mean, 46.6 years). There were 29 cases of cervical spondylotic radiculopathy and 25 cases of cervical spondylotic myelopathy. The disease duration ranged from 3 to 48 months, with an average of 16.8 months. In the 55 patients, 44 were single-segment ACDF and 10 were double-segment ACDF. Sagittal parameters of cervical spine were measured on cervical X-ray films before operation and at last follow-up, including C 2-7 Cobb angle, C 2-7 sagittal vertical axis (C 2-7 SVA), C 7S, and segment Cobb angle (SCobb), and the changes of C 2-7 Cobb angle (the difference between the last follow-up and the preoperative angle) were calculated. Pearson correlation was used to analyze the correlation between the parameters before operation and at last follow-up. According to the preoperative median value of C 7S (15°), the patients were divided into group A (C 7S 0.05）。根据患者术前 C 7S 中位数分组，A 组 28 例，C 7S 为（11.82±3.60）°；B 组 26 例，C 7S 为（20.77±4.09）°；两组患者性别及年龄比较差异均无统计学意义（ P>0.05）。A 组术前 C 2～7 Cobb 角和 C 2-7 SVA 显著小于 B 组（ P 0.05）；但 A 组 C 2～7 Cobb 角变化值显著大于 B 组（ t=2.321， P=0.024）。. Conclusion: Preoperative C 7S≥15° group has more physiological lordosis before operation, but its postoperative cervical curvature changes less, while ACDF is more conducive to correct the preoperative C 7S<15 ° cervical curvature.