The Impact of Obesity on Spine Surgery Operative Time: A Quantitative Analysis

Study Design Retrospective cohort study. Objective The study aimed to determine how obesity modifies operative time and the influence of operative time on wound complications or surgical infections for patients undergoing a single-level anterior cervical discectomy and fusion (ACDF) or a single-level posterior lumbar fusion (PLF). Methods The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried to identify patients who had undergone either a single-level ACDF or a single-level PLF. Multivariable regression was used to determine the relationship between obesity and operative time as well as the relationship between operative time and wound complications or surgical infections. Results For every BMI unit of increase, ACDF operative times increased by 0.38 minutes while PLF operative times increased by 0.84 minutes. As operative time increased from the 25 th to 75 th quartile, the probability of a wound complication increased by 19.7% after a single-level PLF procedure, while there was an increase by 17.1% after a single-level ACDF procedure. The probability of a postoperative surgical infection increased by 30.0% and 12.5% for ACDF and PLF procedures, respectively. Conclusion Increases in BMI lead to a greater increase in operative time for patients undergoing single-level PLF compared to patients undergoing single-level ACDF. Patients undergoing either procedure with a prolonged operative time have a greater probability of developing a wound complication or surgical infection. This is the first study to establish a quantitative relationship between obesity and operative time in spine surgery.