Impact of repeated hilar clamping on renal function during laparoscopic and robot-assisted partial nephrectomy

Background and Purpose: Conventional wisdom and small animal studies suggest repeated hilar clamping during partial nephrectomy is deleterious to renal function. We describe the impact of repeated renal hilar clamping during laparoscopic partial nephrectomy (LPN) and robot-assisted partial nephrectomy (RPN) on the overall function of the operated kidney. Patients and Methods: A retrospective analysis of all patients undergoing RPN or LPN with repeated hilar clamping was performed. Patient and tumor characteristics were recorded. All patients had preoperative and postoperative mercaptoacetyltriglycine (MAG)3 renal scans, and the change in function was calculated. Change in glomerular filtration rate (GFR) was calculated with the modified Modification of Diet in Renal Disease equation as well. Results: Seven patients were studied with an average age of 60 and a body mass index of 32. Tumors averaged 3.6 cm, and there were four and three right- and left-sided tumors, respectively. The reasons for repeated clamping were bleeding in three patients and either gross or microscopic positive margins in four patients, all of whom had repeated resection. The average initial clamp time was 20 minutes, and the average reclamp time was 12 minutes. The average operative time was 185 minutes. and average blood loss was 171 mL. All renal units were functioning postoperatively. The average change in absolute renal function on the operated kidney was -4.9%, and the relative loss of function was -10%, both measured on MAG3 scan. The average GFR before surgery was 61.4 (mL/min/1.73m ²); after surgery, the average GFR was 57.1 (mL/min/1.73m ²), for an average loss of -7%. The range of change in GFR was from 0% to -23%. Conclusions: Although not optimal, repeated clamping of the renal hilum during partial nephrectomy to control bleeding or to obtain a clear surgical margin is associated with minimal loss of renal function.