Age as a Risk Factor for Complications Following Anterior Cervical Discectomy and Fusion Analysis From the Michigan Spine Surgery Improvement Collaborative (MSSIC)

Study Design. Retrospective analysis of prospectively collected registry data using multivariable analyses of imputed data Objective. We sought to demonstrate that age would not be associated with complications in patients undergoing anterior cervical discectomy and fusion (ACDF). Summary of Background Data. Elderly patients (>= 70 yrs) undergoing ACDF are considered a higher risk for complications. However, conclusive evidence is lacking. The Michigan Spine Surgery Improvement Collaborative (MSSIC) is a quality improvement collaborative with 30 hospitals across Michigan. Methods. The study included all patients who had 1 to 4 level ACDF (September 2015-August 2019) for 90-day complications. Major and minor complications were defined using a validated classification. Multiple imputations were used to generate complete covariate datasets. Generalized estimating equation model was used to identify associations with complications using the whole cohort and elderly subgroup analyses. Bonferroni correction was used. Results. Nine thousand one hundred thirty five patients (11.1% >= 70 yrs and 88.9% <70 yrs) with 2266 complications were analyzed. Comparing elderly versus non-elderly, the elderly had a significantly higher rate of any complications (31.5% vs. 24.0%, P < 0.001) and major complications (14.1% vs. 7.0%, P < 0.001). On multivariable analysis, age was not independently associated with any complication. POD#0 ambulation and preop independent ambulation were independently associated with significantly decreased odds of any complication. In the elderly, independent preoperative ambulation was protective for any complication (odds ratio [OR] 0.53, 0.39-0.73 95% confidence interval [CI]), especially major complications (OR 0.41, 0.27-0.61 95% CI). Conclusion. Age was not an independent risk factor for complications in patients that underwent ACDF. In the elderly, independent preoperative ambulation was especially protective for major complications.