Perioperative Factors Associated with the Conversion of Robotic-Assisted Partial Nephrectomy to Open Partial and Radical Nephrectomy

Objective: To evaluate factors associated with the conversion of robotic-assisted partial nephrectomy (RAPN) to open partial nephrectomy (OPN) and radical nephrectomy (RN). Methods: We retrospectively reviewed 775 consecutive RAPNs from a single surgeon. Perioperative factors were evaluated for association with RAPN conversion such as Mayo Adhesive Probability (MAP) score, length of stay (LOS), and operative time (OT). A logistic regression model was utilized to evaluate factors associated with conversion and reported as odds ratio (OR) with 95% confidence intervals. Continuous and categorical variables were analyzed through the Wilcoxon rank-sum and chi-square tests. Results: Thirty-two (4.1%) patients had a conversion including 19 (2.5%) to OPN and 13 (1.7%) to RN. OPN conversions were related to bleeding ( n = 7), inability to dissect perinephric fat ( n = 4), liver retraction ( n = 1), and failure to secure renal hilum/progress ( n = 7). In contrast, conversions to RN were due to tumor involvement of the renal vein ( n = 3) or ureter ( n = 5) and inability to achieve negative margins ( n = 5). Patients in the conversion cohort were more likely to have larger tumor size (3.7 vs 2.8 cm; p < 0.001) and higher MAP score (3.0 vs 2.0; p = 0.04). Median LOS was higher in the conversion group (3.0 vs 2.0 days; p = 0.003). Conversions were associated with postoperative complications (28.1% vs 13.7%; p = 0.023). After adjusting tumor size in our regression model, longer OT and dissection time were statistically higher in the conversion group (OR = 2.19 [1.50–3.21]; p < 0.001 and OR = 2.67 [1.82–3.94]; p < 0.001, respectively). Conclusions: Larger tumor size and higher MAP score were associated with conversions during RAPN. Conversions were associated with higher LOS, longer OT, and postoperative complications.