Off-clamp robot-assisted partial nephrectomy: Initial Washington University experience

Background and Purpose: Because of the impact warm ischemia time may have on renal function, various surgical techniques have been proposed to minimize or eliminate warm ischemia. The purpose of this study is to evaluate our initial renal functional outcomes of off-clamp robot-assisted partial nephrectomy (RAPN), while assessing the safety profile of this unconventional surgical approach. Patients and Methods: We performed a retrospective review of our off-clamp RAPN experience between August 2007 and January 2012. All patients with baseline and postoperative serum creatinine determinations were included. Patient demographics, operative information, perioperative outcomes, and renal functional outcomes were evaluated for this cohort. Results: Forty-two patients with a mean age of 59.9 years (standard deviation [SD]=12) had a median follow-up of 100 days (range 1-1007 days). In all cases, warm ischemia time was 0 minutes. Mean operative time was 143 minutes (SD=59), and median estimated blood loss was 138mL (range 50-1500mL). No intraoperative complications were encountered, and all surgical margins were negative. Our postoperative complication rate was 14.3%. At the most recent follow-up, the mean estimated glomerular filtration rate (eGFR) was 76.2mL/min/1.73m² (SD=27.6), compared with 78.5mL/min/1.73m² (SD=28.9) preoperatively (P=0.11). Therefore, the mean eGFR decline of 2.3mL/min/1.73m² (SD=9.1) was not significant. Conclusions: Off-clamp RAPN is associated with minimal morbidity and minimal decline in renal function on short-term follow-up. Further studies and continued monitoring of renal function are needed to determine if off-clamp RAPN provides any advantage in renal function preservation relative to the traditional RAPN with vascular clamping.