Identification of an Operative Time Threshold for Substantially Increased Postoperative Complications After Thoracolumbar Spine Surgery: A Nationwide Retrospective Cohort Analysis

Background: The literature extensively describes the influence of operative time (OT) on postoperative outcomes, but the extent of its impact on thoracolumbar fusion outcomes remains unclear. This study aims to identify the threshold beyond which OT increases the risk of surgical adverse events and to quantify the association between increased OT and postoperative complications. Methods: A total of 66,904 patients who underwent thoracolumbar fracture surgery between 2010 and 2021 were identified from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) dataset. We used the receiver operating characteristic curve to determine an OT threshold that significantly increased 30-day morbidity. Univariate analysis was performed before and after propensity matching for covariates. Multivariate regression was used to further validate the risk of OT on 30-day morbidity. Results: A total of 66,898 patients met the inclusion criteria, of whom 20% experienced 30-day morbidity and 0.38% 30-day mortality. An OT threshold of 215 minutes best discriminates risk of 30-day morbidity. On univariate analysis, longer OT was significantly associated with all-cause 30-day morbidity (odds ratio, 3.28; 95% confidence interval, 3.12–3.45), including wound infection, increased length of stay, deep vein thrombosis, bleeding requiring transfusion, pneumonia, pulmonary embolism, urinary tract infection, and failure to wean off ventilation. Further analysis with multivariate regression validated that OT was independently associated with an increased risk of overall complications (odds ratio, 3.50; confidence interval, 3.25–3.78; P < 0.0001). Conclusions: This study shows that OT ≥215 minutes is strongly associated with increased incidence of postoperative adverse events and longer hospital length of stay after thoracolumbar spine fixation.