Risk factors for non-fusion segment disease after anterior cervical spondylosis surgery: a retrospective study with long-term follow-up of 171 patients

• Main Authors: Ziqiang Wang, Liangliang Zhou, Bin Lin, Keran Song, Qinghe Niu, Dongfeng Ren, Jiaguang Tang
• Format: Article
• Language: English
• Published: BMC 2018-02-01
• Series: Journal of Orthopaedic Surgery and Research
• Subjects: Non-fusion segment disease; Anterior cervical arthrodesis; Cervical spondylosis; Adjacent segment disease
• Online Access: http://link.springer.com/article/10.1186/s13018-018-0717-1

Abstract Background The purpose of this study was to investigate the incidence and causes of non-fusion segment disease (NFSD), both adjacent and non-adjacent to a fused segment, after anterior cervical arthrodesis. Methods This is a single-center study. Between January 1998 and January 2011, two surgeons’ 171 patients who had an anterior cervical decompression and fusion were followed clinically for more than 5 years. The correlation between the incidence of symptomatic non-fusion segment disease and the following clinical parameters (age at operation, fusion levels,) and radiological parameters (number of patients who had a plate, anterior cervical decompression and fusion (ACDF) or corpectomies, preoperative and postoperative cervical spine alignment, Pavlov’s ratio at the C5 level, and preoperative existence of a non-fusion segment degeneration on magnetic resonance imaging) was evaluated. Results Of the 171 patients reviewed, 16 patients had non-fusion segment disease (9.36%), of which 12 had adjacent segment disease and 4 had non-adjacent segment disease. Postoperative cervical lordosis in the non-fusion segment disease group was significantly smaller than that of the disease-free group (P < 0.001). Fusion levels in the NFSD group were 1.69 whereas 2.26 in disease-free group (P = 0.005). The incidences of disc degeneration in unfused segments was more severe in the NFSD group than in the disease-free group (P = 0.004). The results of binary logistic regression showed that the major factor affecting NFSD is postoperative cervical lordosis (P = 0.000) followed by disc degeneration (P = 0.024). The other parameters did not show a statistically significant difference. Conclusions The incidence of symptomatic non-fusion segment disease after anterior cervical arthrodesis has multifactorial causes. Postoperative cervical lordosis and disc degeneration in non-fusion segments were major factors in the incidence of NFSD.