Medical Student University of Utah School of Medicine Salt Lake City, Utah, United States
Introduction: Spine surgery can improve quality of life in elderly patients; however, both advanced age and prolonged operative duration carry higher complication rates. We sought to identify whether a threshold exists beyond which either operative duration or advanced age results in increased complication risk. Secondarily, we examined whether prolonged surgery or advanced age poses greater complication risk, which is yet unknown.
Methods: All spine surgeries in the 2006-2019 American College of Surgeons National Surgical Quality Improvement database were captured. Patients < 65 years or with infection/trauma/tumors were excluded. Patients were subdivided into five groups based on operation duration, and univariate analysis compared 30-day complication rates between groups. Confounder-adjusted multivariate models quantified the risk of prolonged operative duration on complications. Cases were stratified by age, and the complication rates of each age group per operative duration group were calculated. A generalized linear model (GLM) assessed the individual and combined effect strength of age and operative duration on complications.
Results: A total of 87,705 patients were included. Overall, 30-day complication rates rose nonlinearly as operative duration increased, with a sharp rise after 4.0-4.9 hours (28.3% at 4.0-4.9 hours, 51.7% at ≥5 hours, p < 0.001). Multivariate analysis found operative duration was independently associated with increased risk of overall complications (odds ratio 1.10 → 1.69, p < 0.001) and medical complications (odds ratio 1.19 → 1.98, p < 0.001). Significant increases in complication rates per operative duration group were recorded as age increased (all p< 0.001); however, multivariate analysis found age was not predictive of overall complications within any time grouping. The GLM found operative duration had significantly greater effect (η2p=0.067) than age (η2p=0.003) on overall complication rates.
Conclusion : We identified a 5-hour threshold, after which complication rates dramatically rise in elderly patients. Operative duration had a notably larger effect on overall complication rates than advanced age.
