Predicting surgical outcomes in single-port robot-assisted partial nephrectomy: external validation and comparative analysis of PADUA, RENAL, and SPARE scores

Abstract

PURPOSE: Nephrometry scores are essential tools for classifying and comparing tumor complexity and guiding surgical planning in partial nephrectomy. However, their performance in single-port robot-assisted partial nephrectomy (SP-RAPN) has not been formally assessed. We aimed to externally validate and compare the predictive performance of the Preoperative Aspects and Dimensions Used for an Anatomical (PADUA), Radius-Exophytic/Endophytic-Nearness-Anterior/Posterior-Location (RENAL), and Simplified PADUA Renal (SPARE) nephrometry scores in patients undergoing SP-RAPN. METHODS: We retrospectively reviewed 211 consecutive patients who underwent SP-RAPN for solitary ≤ cT2 renal tumors at two academic centers between 2019 and 2024. The primary endpoint was Trifecta achievement, defined as the simultaneous presence of negative surgical margins, absence of perioperative complications, and warm ischemia time ≤ 25 min. Discrimination and clinical utility of each nephrometry score were assessed using receiver operating characteristic (ROC) curve analysis and decision curve analysis (DCA). Multivariable logistic regression adjusted for relevant clinical covariates. RESULTS: Trifecta was achieved in 50.7% of patients. The SPARE score demonstrated the highest discriminative performance (AUC 0.681), followed by PADUA (0.661) and RENAL (0.654), though these differences were not statistically significant. DCA showed overlapping net benefit curves, with SPARE offering marginally superior. Limitations include the retrospective design and underrepresentation of highly complex tumors. CONCLUSIONS: PADUA, RENAL, and SPARE scores show comparable performance in predicting Trifecta achievement in the setting of SP-RAPN. SPARE may perform slightly better, and it represents a more practical choice for routine preoperative assessment due to its ease of use.