The Nephrometry Score: Is It Effective for Predicting Perioperative Outcome During Robot-Assisted Partial Nephrectomy?

PURPOSE: Robot-assisted partial nephrectomy (RPN) has emerged as an alternative treatment for the management of small renal masses. This study was designed to investigate parameters that predict perioperative outcomes during RPN. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 113 patients who underwent RPN between September 2008 and May 2012 at the Seoul National University Bundang Hospital. Clinical parameters, including warm ischemia time (WIT), estimated blood loss (EBL), and R.E.N.A.L and PADUA scores, were evaluated to predict perioperative outcomes. RESULTS: Of the 113 patients, 81 were men and 32 were women. The patients' mean age was 53.5 years, and their mean body mass index was 22.3 kg/m(2). Age, gender, and mass laterality had no effect on perioperative complications, WIT, or EBL. Univariate analysis revealed that a distance between the tumor and the collecting system of ≤4 mm or a renal mass size of >4 cm were associated with adverse profiles of complications, WIT, and EBL. However, multivariate analysis showed no association between the predictive parameters and tumor complexity as assessed by nephrometry scores. Tumor size of >4 cm increased the risk of blood loss >300 mL (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.3.9.7; p=0.016). A distance between the tumor and the collecting system of ≤4 mm was associated with increased risk of WIT exceeding 20 minutes (OR, 2.8; 95% CI, 1.3.6.3; p=0.012). CONCLUSIONS: Tumor size and proximity of the mass to the collecting system showed significant associations with EBL and WIT, respectively, during RPN. The R.E.N.A.L and PADUA nephrometry scoring systems did not predict perioperative outcomes.