Longer Operative Time in Elderly Patients Undergoing Posterior Lumbar Fusion Is Independently Associated With Increased Complication Rate

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine the effects of operative time on postoperative complications in patients age 65 and older undergoing posterior lumbar fusion. METHODS: All patients age 65 and older undergoing posterior lumbar fusion were identified in the 2012 to 2015 American College of Surgeons National Surgical Quality Improvement Program database. The primary outcome measures were complications occurring up to 30 days postoperatively, including death, any complication, and complication subtypes. The primary independent variable was operative duration. Both bivariate and multivariate analyses utilized logistic regression and analyzed operative duration as a continuous variable. Statistical significance was considered P < .05. RESULTS: A total of 4947 patients age 65 and older undergoing posterior lumbar fusion were identified. The mean operative time was 3.3 hours (SD 1.7). The overall complication rate was 13.4% (n = 665). In multivariate analysis, each incremental hour of operative time was associated with increased risk of postoperative thromboembolism (odds ratio [OR] = 1.23; 95% confidence interval [CI] = 1.10-1.37), transfusion (OR= 1.25; 95% CI = 1.18-1.32), urinary tract infection (OR = 1.21; 95% CI = 1.10-1.32), and total postoperative complications (OR = 1.22; 95% CI = 1.16-1.27). CONCLUSION: For patients age 65 and older undergoing posterior lumbar fusion, longer operative time is associated with greater risk for thromboembolism, transfusion, intubation, kidney injury, urinary tract infection, surgical site infection, and overall postoperative complications. This data highlights several specific complications that are influenced by operative time in older patients, and further supports the need for future protocols that seek to safely minimize operative time for posterior lumbar fusion.