Predictors of poor outcomes after posterior decompression surgery in patients with degenerative cervical myelopathy

Retrospective multicenter study. To identify predictors associated with failure of neurological improvement after posterior decompression surgery for degenerative cervical myelopathy (DCM). 17 institutions in Japan. Patients who underwent posterior decompression surgery and were followed up for >1 year were enrolled. The Japanese Orthopedic Association (JOA) recovery rate was determined, and patients were divided into three outcome groups based on the JOA recovery rate: fair (recovery rate, <22.2%: mean-1SD), moderate (22.3%–77.1%), and good (>77.2%: mean+1 SD) groups. Demographic information, postoperative complications, and radiographic parameters were assessed, and predictors of poor outcomes were identified using the multinominal logistic regression analysis. Of 868 patients enrolled, 140 (16.1%), 586 (67.5%), and 142 (16.3%) were assigned to the fair, moderate, and good groups, respectively, with mean JOA recovery rates of 6.2% ± 13.7%, 50.1% ± 15.0%, and 90.6% ± 8.3%. Although there were significant differences in the frequency of diabetes mellitus among the three groups in the univariate analysis (26.4% vs. 23.0% vs. 14.1%; p = 0.03), the multinominal regression analysis revealed that old age was a significant independent predictor of poor outcomes in the comparison between the fair and good groups (odds ratio [OR], 1.62; 95% confidence interval [CI], 1.27–2.07; p < 0.01). Old age was also significantly associated with failure of neurological improvement between the fair and moderate groups (OR, 1.35; 95% CI 1.15–1.59; p < 0.01). Old age may be an independent predictor of failure of neurological improvement after posterior decompression surgery in patients with DCM.