ABSTRACT Objectives: The aim of this study was to evaluate whether criteria exist to guide election between the use the three- or four-arm technique in robotic partial nephrectomy (RPN) instead of just the surgeon’s preference. Material and Methods: We performed a retrospective review of 80 patients submitted to RPN from May 2016 to February 2020. The patients were divided into two groups of 40, the first submitted to the surgical procedure with use of three robotic arms and the second with four arms. The group division was performed independently of the complexity of the cases, age or gender of the patients and laterality of the renal lesions. Peri- and postoperative data were analyzed for comparison between the two groups. Results: Both techniques had similar oncological outcomes (positive tumor margins), renal function preservation (warm ischemia time) and hemorrhagic complications (estimated blood loss and renal artery pseudoaneurysm), with a small difference in the need for blood transfusion, favoring the technique with three arms. Conclusions: The two robotic partial nephrectomy techniques had similar oncological and postoperative outcomes, with minimal perioperative complications. The three-arm technique is safe and feasible regardless of the complexity and size of the tumor. Additionally, the use of the three-arm technique reduced surgery costs by US$ 413.00 per patient.

ABSTRACT Introduction: Nephrometric scores play an interesting role in nephron sparring surgery (NSS) planning. The aim of this study is to evaluate if R.E.N.A.L. score (RS) is capable to predict the occurrence of adverse events in laparoscopic NSS. Materials and Methods: We prospectively studied 150 laparoscopic NSS between 2015 and 2018 to evaluate the relationship between RS and incidence of adverse events. Clavien 3 or superior complications, warm ischemia time (WIT) over 30 minutes, tumor violation, positive surgical margins (PSM) and necessity of amplification of renal parenchyma during the resection of the masses to obtain free margins were considered as adverse events. We compared each item of the RS isolated and divided the patients between low risk and high risk. Results: Adverse results occurred in 48 cases (32%). Amplification of the margin of resection was observed in 28 cases (19%). WIT exceeded 30 minutes in 9 cases (6.1%), complications Clavien 3 or superior occurred in 13 cases (9%) and PSM were detected en 6 cases (4%). Comparing the patients with adverse outcomes and each item of the RS we did not find any statistical difference, but when divided into high risk and low risk, we found that patients in the high risk group had a higher tendency to present ad-verse results - 25.84% vs. 44.26% (p=0.03). Conclusions: RS system is a good way to predict adverse outcomes in NSS, especially in cases over 7. Further studies should focus on robotic approach and patient's characteristics other than the masses’ aspects.