Higher RENAL nephrometry score is predictive of longer warm ischemia time and collecting system entry during laparoscopic and robotic-assisted partial nephrectomy

Objective: To investigate the predictive value of the RENAL Nephrometry Score (RNS) on operative outcomes during both laparoscopic partial nephrectomy (LPN) and robotic-assisted partial nephrectomy (RPN). Methods: We reviewed 67 consecutive patients with suspicious renal lesions and available radiographic data who underwent LPN or RPN by a single surgeon. Data included operative type, body mass index (BMI), gender, age, and side of tumor. RNSs were recorded using either magnetic resonance imaging or computed tomography scans. Warm ischemia time (WIT), estimated blood loss (EBL), and collecting system entry (CSE) were the endpoints for the analyses. Results: Total RNS entered as a continuous or dichotomous variable (<7 or <7), R-score, and N-score were independent predictors of WIT on multivariable analyses (P <.001, P =.001, P =.026, and P <.01, respectively). The total RNS and N-score were predictive of CSE in univariate analysis (P <.001). Neither total RNS nor its individual components were predictive of EBL. Conclusion: Total RNS, as well as the N- and R-scores, can help predict both longer WIT and CSE during LPN and RPN. The RNS and its individual components may be useful in the preoperative planning and counseling of patients undergoing LPN or RPN.