Changes in renal function after nephron‐sparing surgery in patients with a normal contralateral kidney

Objectives:  To evaluate the pattern of the recovery of the overall and isolated renal function in patients with a normal contralateral kidney undergoing nephron‐sparing surgery (NSS). Methods:  Between 2003 and 2006, 62 patients underwent open NSS at our institution. Among them, 35 having unilateral renal tumors smaller than 7 cm and a normally functioning contralateral kidney were included in the analysis. The estimated glomerular filtration rate (eGFR) was checked preoperatively, and 2 weeks, 6 months and 1 year postoperatively, and annually thereafter. Renal scintigraphy was carried out before the procedure, at 6 months and 1 year postoperatively to measure individual renal uptake. Results:  eGFR was 80.9, 70.8, 76.7, 76.9, 75.8, 76.9, 78.6 and 78.2 mL/min/1.73 m 2 preoperatively, and postoperatively at 2 weeks, 6 months, 1, 2, 3, 4 and 5 years, respectively. Average isolated differential function of the operated kidney decreased 11.6% and 5.6% at 6 months and 1 year after surgery, respectively. Conclusions:  Within 6 months after NSS, the overall renal function recovered up to 95% by a compensatory increase of contralateral renal function. Thereafter, isolated function of the operated kidney recovered slowly.