Urine leak in minimally invasive partial nephrectomy: analysis of risk factors and role of intraoperative ureteral catheterization

Purpose: To investigate risk factors for urine leak in patients undergoing minimally invasive partial nephrectomy (MIPN) and to determine the role of intraoperative ureteral catheterization in preventing this postoperative complication. Materials and Methods: MIPN procedures done from September 1999 to July 2012 at our Center were reviewed from our IRB-approved database. Patient and tumor characteristics, operative techniques and outcomes were analyzed. Patients with evidence of urine leak were identified. Outcomes were compared between patients with preoperative ureteral catheterization (C-group) and those without (NC-group). Univariable and multi-variable analyses were performed to identify factors predicting postoperative urine leak. Results: A total of 1,019 cases were included (452 robotic partial nephrectomy cases and 567 laparoscopic partial nephrectomy cases). Five hundred twenty eight patients (51.8%) were in the C-group, whereas 491 of them (48.2%) in the NC-group. Urine leak occurred in 31(3%) cases, 4.6% in the C-group and 1.4% in the NC-group (p<0.001). Tumors in NC-group had significantly higher RENAL score, shorter operative and warm ischemic times. On multivariable analysis, tumor proximity to collecting system (OR=9.2; p<0.01), surgeon's early operative experience (OR=7.8; p<0.01) and preoperative moderate to severe CKD (OR=3.1; p<0.01) significantly increased the odds of the occurrence of a postoperative urine leak. Conclusion: Clinically significant urine leak after MIPN in a high volume institution setting is uncommon. This event is more likely to occur in cases of renal masses that are close to the collecting system, in patients with preoperative CKD and when operating surgeon is still in the learning curve for the procedure. Our findings suggest that routine intraoperative ureteral catheterization during MIPN does not reduce the probability of postoperative urine leak. In addition, it adds to the overall operative time.