Risk factors associated with clinical adjacent segment pathology following multi-level cervical fusion surgery

Few clinical studies investigate risk factors associated with clinical adjacent segment pathology (CASP) following multi-level cervical fusion surgery. The aim is to record the incidence of postoperative CASP in patients after at least 2 years′ follow-up and to identify possible risk factors that may be associated with the CASP after multi-level cervical surgery. We retrospectively reviewed patients who underwent multi-level cervical surgery in our hospital from January 2004 to February 2016. All patients underwent more than 2 years′ follow-up. The diagnosis of CASP is according to clinical symptoms as well as image findings. Potential risk factors were collected from demographic data and radiographic images. A total of 301 patients after multi-level cervical surgery were analyzed. During follow-up, 28 patients (9.3%) were diagnosed as having CASP. Among these patients, 7 showed symptoms of CASP within 3 years after surgery, 6 showed symptoms between 3 and 5 years, 14 showed symptoms between 5 and 10 years, and the last one showed symptoms more than 10 years later. In the multivariate analysis, degeneration of adjacent segment (OR, 1.592; 95% CI, 1.113–2.277), decreased Cobb angle in fused vertebrae (OR, 2.113; 95% CI, 1.338–3.334) and decreased Cobb angle in cervical spine (OR, 1.896; 95% CI, 1.246–2.886) were correlated with the incidence of CASP during follow-up. The incidence of CASP following multi-level cervical surgery was 9.3% with a mean of about 70 months′ follow-up. Patients with preoperative degeneration of adjacent segment and postoperative imbalance of sagittal alignment have a higher risk of developing CASP after multi-level cervical surgery.