关键词: 颈椎病, 颈椎前路减压融合, 矢状位参数, 矢状位失衡, 临床疗效

Abstract: BACKGROUND: Some patients with cervical spondylosis have not been fully corrected sagittal position balance after cervical surgery, and this continuous sagittal position imbalance may be an important reason for the poor long-term clinical outcome of patients.
OBJECTIVE: To analyze the correlation between the cervical sagittal position balance parameters and their changes and the clinical efficacy of patients in the unbalanced state after anterior cervical decompression and fusion and to explore the necessity of surgical correction of sagittal balance in order to improve the clinical effect in the later stage. 
METHODS: A retrospective analysis was performed on 125 patients with cervical spondylosis who underwent anterior cervical decompression and fusion in the Department of Spinal Surgery of Affiliated Hospital of Southwest Medical University from July 2019 to July 2022. Follow-up patients had good postoperative recovery (neck disability index score less than 10% one week after surgery) and had complete follow-up data. According to the axial vertical distance (C2-7 SVA) in sagittal position one week after surgery, patients were divided into type I imbalance group (C2-7 SVA loss ≤ 5 mm, n=27), type II imbalance group (C2-7 SVA loss > 5 mm, and ≤ 10 mm, n=19), and type III imbalance group (C2-7 SVA loss> 10 mm, n=12), and non-unbalanced group (C2-7 SVA in the normal range, n=67). The changes of visual analog scale score and neck disability index were compared among groups postoperatively and the last follow-up, as well as the changes of imaging sagittal balance parameters C2-7 cobb angle, C2-7 SVA value, neck inclination angle, T1 inclination angle, and thoracic entrance angle. The correlation between the late clinical effect and postoperative cervical sagittal disequilibrium was explored. 
RESULTS AND CONCLUSION: (1) There was no statistical difference in general data among the four groups (P > 0.05). All patients underwent successful surgery without serious complications and postoperative wound infection. The follow-up time was more than 1 year. (2) There was no significant difference in preoperative symptom score and clinical efficacy one week after surgery (P > 0.05). At the last follow-up, pain visual analog scale score, neck disability index and C2-7 SVA were lower than those before surgery but higher than those one week after surgery (P < 0.05). C2-7 cobb angle was increased compared with those before operation (P < 0.05). T1 inclination angle was decreased compared with those before operation (P < 0.05). (3) Pearson correlation test showed that the change of neck disability index was positively correlated with the change of C2-7 SVA (P < 0.05). (4) It is indicated that anterior cervical decompression and fusion is effective in the treatment of cervical spondylosis, and can effectively relieve the symptoms of patients. Patients with more severe cervical sagittal disequilibrium after surgery had worse curative effect in the later period. Continuous sagittal disequilibrium in patients with cervical spondylosis after surgery is an important cause of poor curative effect in the later stage. Clinicians should pay more attention to the correction of cervical sagittal balance before and during surgery, formulate surgical strategies and plans according to sagittal balance parameters before surgery, and correct C2-7 SVA intraoperatively to the normal range.

Key words: cervical spondylopathy, anterior cervical decompression and fusion, sagittal position parameter, sagittal disequilibrium, clinical effect