Cervical sagittal parameters were closely related to Neck Disability Index score after anterior cervical decompression and fusion.

ACDF treatment of CSM is currently recognized as a surgical method with reliable efficacy. However, the cervical radiographic findings in a certain group of patients showed that the symptoms were not completely relieved. This study will investigate the relationship between cervical parameters and prognoses after ACDF surgery. This study collected cases of CSM treated with ACDF in Zhongda Hospital from May 2014 to June 2018. The investigators recorded gender, age, cervical sagittal parameters, fusion segment, BMI, symptom duration, and NDI score. To compare the changes of parameters after surgery and explore the correlation between each factor and NDI score. Generally, cervical lordosis increased and TS-CL decreased after surgery and during follow-up. Postoperative T1S, SVA and SCA decreased significantly compared to preoperative. T1S was positively correlated with CL (r = 0.245), SVA (r = 0.184), and negatively correlated with SCA (r = − 0.314) and NT (r = − 0.222). The last follow-up NDI score was positively correlated with T1S (r = 0.689), SVA (r = 0.155), TS-CL (r = 0.496), and age (r = 0.194), while negatively correlated with SCA (r = − 0.142). A linear regression model was established with the following formula: NDI = 0.809 × (T1S) − 0.152 × (CL) + 1.962 × (Sex) + 0.110 × (Age). T1S (B = 0.205, P < 0.001), CL (B = − 0.094, P = 0.041), and NT (B = 0.142, P = 0.023) were independent risk factors that affected whether the last follow-up NDI score was greater than preoperative. In ACDF treatment of CSM, there exists a close correlation between cervical sagittal parameters and NDI scores. T1S, CL, sex, and age were linearly dependent on NDI scores. The increase of T1S, NT, and the decrease of CL were risk factors that affected follow-up NDI score greater than preoperative. Reducing T1S is beneficial to clinical recovery.