Comparison of preoperative adaptive enlargement of the contralateral normal kidney in patients nephrectomized for benign non-functioning kidney versus renal cell carcinoma.

Abstract

To investigate the potential effects of preoperative volumetric compensation of the contralateral normal kidney on renal function after simple nephrectomy or radical nephrectomy. A total of 306 patients (80 simple nephrectomy patients and 226 radical nephrectomy patients) with 1:3 propensity score matching were included between October 1996 and December 2013. Preoperative three-dimensional kidney volume was estimated from computed tomography images using a specialized volumetric program. Glomerular filtration rate assessed using the Chronic Kidney Disease Epidemiology Collaboration equations was checked preoperatively, 1 week, 3 months and 1 year after nephrectomy. Preoperative mean Chronic Kidney Disease Epidemiology Collaboration glomerular filtration rate was 76.5 mL/min/1.73 m(2) in the simple nephrectomy group and 89.2 mL/min/1.73 m(2) in the radical nephrectomy group. In simple nephrectomy patients, mean Chronic Kidney Disease Epidemiology Collaboration glomerular filtration rate showed a stable pattern up to 3 months (75.5 mL/min/1.73 m(2) at 7 days and 76.2 mL/min/1.73 m(2) at 3 months), and decreased slightly to 72.6 mL/min/1.73 m(2) at 1 year. However, in radical nephrectomy patients, mean Chronic Kidney Disease Epidemiology Collaboration glomerular filtration rate decreased immediately to 63.4 mL/min/1.73 m(2) at 7 days after surgery, and then increased gradually to 64.6 mL/min/1.73 m(2) at 3 months and 65.9 mL/min/1.73 m(2) at 1 year. Preoperative mean contralateral normal kidney volume was 225.7 mL in the simple nephrectomy group and 180.1 mL in the radical nephrectomy group (P < 0.001). The contralateral normal kidney volume to total normal kidney volume ratio was 0.74 in the simple nephrectomy group and 0.51 in the radical nephrectomy group (P < 0.001). Preoperative volumetric compensation of the contralateral normal kidney is important to maintain postoperative renal function in patients undergoing nephrectomy.