The RENAL Nephrometry Score and the PADUA Classification for the Prediction of Perioperative Outcomes in Patients Receiving Nephron-Sparing Surgery: Feasible Tools to Predict Intraoperative Conversion to Nephrectomy

Abstract

Objective: To evaluate the potential of the RENAL nephrometry score and the PADUA classification in the prediction of perioperative outcomes represented by intraoperative conversion to nephrectomy in patients with renal tumors for which nephron-sparing surgery (NSS) was attempted. Methods: Recent 100 open NSSs attempted for cT1 renal tumors at a single institution were studied retrospectively. Results: With the RENAL, the operation time and ischemia time were longer in the high complexity group (p = 0.01 and p = 0.03, respectively), and blood loss was seemingly greater in this group (394 vs. 220 and 167 ml, p = 0.09). Conversion to nephrectomy was more frequent in the high complexity (4 procedures, 33.3%) than in the low (0%) and moderate (1 procedures, 1.5%) groups (p < 0.01). Regarding the PADUA, the operation time, blood loss and ischemia time increased according to the complexity (p = 0.04, p = 0.02, and p = 0.02, respectively). Conversion to nephrectomy was more frequent in the high complexity (4 procedures, 22.2%) than in the low (0%) and moderate (1 procedure, 1.8%) groups (p < 0.01). In patients with achieved NSS, postoperative estimated glomerular filtration rate was more impaired in the high complexity group in the PADUA (p = 0.02), although not significant in the RENAL (p = 0.11). Conclusions: Both the RENAL and PADUA are useful in the prediction of conversion to nephrectomy in addition to NSS-associated perioperative outcomes.