Split renal function of both kidneys after robot-assisted partial nephrectomy for renal tumor larger than 4 cm.

PURPOSE: Relative few studies reported the changes in split renal function using renal scintigraphy for robot-assisted partial nephrectomy (RaPN) for renal tumor >4 cm. This study aimed at demonstrating that RaPN is safe for renal tumor >4 cm without damaging the renal function of ipsilateral and contralateral kidney.

METHODS: Patients who underwent RaPN for single renal tumor from December 2009 to December 2013 were identified from a prospectively collected database. We compared demographic, perioperative, and postoperative outcomes between patients with renal tumor >4 cm (case group) and patients with renal tumor ≦4 cm (control group). Renal function was assessed by serum creatinine, estimated glomerular filtration rate, and effective renal plasma flow (ERPF).

RESULTS: One hundred and three consecutive patients (45 in case group and 58 in control group) were identified. Case group had significantly longer operative time (P = 0.011), longer warm ischemia time (P < 0.001), and more estimated blood loss (P = 0.010) than control group. Only one patient in the case group had conversion surgery. There was no significant difference regarding hospital stay, blood transfusion, complications rate, and positive surgical margin. The changes in ipsilateral ERPF and contralateral ERPF were not significantly different between groups (ipsilateral kidney: -10.5 vs. -12.5%, P = 0.989; contralateral kidney: -3.6 vs. -5.2%, P = 0.611).

CONCLUSIONS: RaPN is a safe and feasible modality of nephron-sparing surgery for renal tumor >4 cm, as it is for renal tumor ≦4 cm.