Multivariate analysis of poor outcome after anterior surgery in multilevel cervical spondylotic myelopathy patients with heterotopic ossification and preoperative kyphotic alignment

The aim of this study was to evaluate the risk factors for poor outcome in patients who underwent multi-segmental anterior surgery, and analyze postoperative complications. We retrospectively reviewed 158 patients after anterior surgery due to multilevel cervical spondylotic myelopathy (m-CSM) between June 2008 and June 2016. Adjusted ORs and 95% CIs were determined by multivariate logistic regression analysis. Cutoff values and the area under the curve for continuous risk factors were calculated through receiver operating characteristic curve analysis. The chi-squared test was performed for the comparison of complications among the three surgical groups. By analyzing 105 patients with good outcome and 53 patients with poor outcome, we established that the risk factors for poor outcome were advanced age (OR =1.12, =0.003), longer duration of symptoms (OR =1.07, =0.028), and bigger kyphotic angle at final follow-up (OR =1.29,