Effect of anterior cervical discectomy and decompression with different fusion segments on sagittal spine-pelvis balance

To explore the effect on sagittal spine-pelvis balance of different fusion segments in anterior cervical discectomy and fusion (ACDF). The clinical data of 326 patients with cervical spondylotic myelopathy, treated by ACDF between January 2010 and December 2016, was retrospectively analysed. There were 175 males and 151 females with an average age of 56 years (range, 34-81 years). Fusion segments included single segment in 69 cases, double segments in 85 cases, three segments in 90 cases, and four segments in 82 cases. Full spine anterolateral X-ray films were performed before operationand at 12 months after operation. The spine-pelvis parameters of fusion segments were measured and compared. The parameters included C Cobb angle, C Cobb angle, C sagittal vertical axis (C SVA), T slope (T S), thoracic inlet angle (TIA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), C sagittal vertical axis (C SVA), T pelvic angle (TPA). The Japanese Orthopaedic Association (JOA) score