Multi-institutional Retrospective Validation and Comparison of the Simplified PADUA REnal Nephrometry System for the Prediction of Surgical Success of Robot-assisted Partial Nephrectomy

Abstract

BackgroundThe use of a nephron-sparing surgery for the treatment of localized renal masses is being pushed to more challenging cases. However, this procedure is not devoid of risks, and the Radius, Exophytic/Endophytic, Nearness, Anterior/Posterior, Location (RENAL) and Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) classifications are commonly employed in the prediction of complications. Recently, the Simplified PADUA REnal (SPARE) scoring system has been proposed with the aim to provide a more simple system, to improve its reproducibility to predict postoperative risks. ObjectiveWe aim to retrospectively validate and compare the proposed new SPARE system in a multi-institutional population. Design, setting, and participantsThe Transatlantic Robotic Nephron-sparing Surgery (TRoNeS) study group collected data from 737 patients subjected to robot-assisted partial nephrectomy (RAPN) between 2010 and 2016 at three tertiary care referral centers. Of these patients, 536 presented complete demographic and clinical data. Outcome measurements and statistical analysisRenal masses were classified according to the SPARE, RENAL, and PADUA nephrometry scores, and surgical success was defined according to the margin, ischemia, and complication scores. Results and limitationsOf 536 patients, 340 were male; the median age was 61 (53–69) yr and preoperative tumor size was 30 (22–43) mm. The margin, ischemia, and complication score was achieved in 399 of cases (74.4%). All three nephrometry scores were significant predictors of surgical outcomes both in univariate and in adjusted multivariate logistic regression model analysis. In accuracy analysis, the area under the curve (AUC) of the SPARE scoring system (0.73) was significantly higher than those of the PADUA (0.65) and RENAL (0.68) nephrometry scores in predicting surgical success. ConclusionsThe SPARE score appears to be a promising and reliable score for the prediction of surgical outcomes of RAPN, showing a higher accuracy relative to the traditional PADUA and RENAL nephrometry scores. Further, prospective studies are warranted before its introduction in clinical practice. Patient summaryThe Simplified PADUA REnal (SPARE) score is a reproducible and simple nephrometry score, offering better predictive capabilities of surgical success and complications.