Ureteral injuries in colorectal surgery and the impact of laparoscopic and robotic-assisted approaches.

BACKGROUND Ureteral injury is a feared complication in colorectal surgery that has been increasing over the past decade. Some have attributed this to an increased adoption of minimally invasive surgery (MIS), but the literature is hardly conclusive. In this study we aim to further assess the overall trend of ureteral injuries in colorectal surgery, and investigate propensity adjusted contributions from open and MIS to include robotic-assisted surgery. METHODS This is a retrospective analysis of colorectal surgeries from 2006 to 2016 using the Nationwide Inpatient Sample (NIS) database. Multivariable logistic regression was performed to identify predisposing and protective factors. Demographics, hospital factors, and case-mix differences for open and MIS were accounted for via propensity analysis. The NIS coding structure changed in 2015, which could introduce a potential source of incongruity in complication rates over time. As a result, all statistical analyses included only the first nine years of data, or were conducted before and after the change for comparison. RESULTS Of 514,162 colorectal surgeries identified there were 1598 ureteral injuries (0.31%). Ureteral injuries were found to be increasing through 2015 (2.3/1000 vs 3.3/1000; p < 0.001) and through the coding transition to 2016 (4.8/1000; p < 0.001). This trend was entirely accounted for by injuries made during open surgery, with decreasing injury rates for MIS over time. Adjusted odds ratio (OR) for ureteral injury with all MIS vs. open cases was 0.81 (95% CI 0.70-0.93, p = 0.003) and for robotic-assisted surgery alone versus open cases was 0.50 (95% CI 0.33-0.77, p = 0.001). CONCLUSIONS The incidence rate of ureteral injuries during open colorectal surgery is increasing over time, but have been stable or decreasing for MIS cases. These findings hold even after using propensity score analysis. More research is needed to further delineate the impact of MIS and robotic-assisted surgery on ureteral injuries.