Ischemic Renal Damage after Nephron-Sparing Surgery in Patients with Normal Contralateral Kidney

Background: Although nephron-sparing surgery (NSS) has been reported not to affect total renal function, the functional damage of the operated kidney is masked by the contralateral kidney in elective indications. Objective: To determine ischemic renal damage after NSS. Design, setting, and participants: From August 2005 to October 2007, 32 consecutive patients with elective indications underwent NSS. The mean tumor diameter was 2.6 cm. Intervention: of our patients, the open surgery was performed in 20 patients, and laparoscopic surgery was performed in 12 patients. NSS was performed by hilar clamping with a warm ischemic time of 24.3 min. Measurements: We analyzed effective renal plasma flow (ERPF) calculated from Tc-99m-mercaptoacetyltriglycine (Tc-99m-MAG-3) renal scintigraphy and renal parenchymal volume (RPV) measured from computed tomography (CT) scan. In addition, we analyzed Tc-99m-MAG-3 uptake regionally in the surgically non-affected parts. Tc-99m-MAG-3 and CT scans were performed preoperatively and 1 wk and 6 mo postoperatively. Results and limitations: One week after NSS, ERPF of the operated kidney decreased by 28.7% (from 158.9 to 113.3 ml/min per 1.73 m(2), p < 0.001), and RPV decreased by 12.6% (from 149.8 to 131.0 cm(3), p < 0.001). These changes were stable for 6 mo. Regional Tc-99m-MAG-3 uptake of the operated kidney with an ischemic time of >25 min decreased to 61.8% after 1 wk and 70.9% after 6 mo. in contrast, with ischemic times within 25 min, regional Tc-99m-MAG-3 uptake was 87.4% after 1 wk and 94.4% after 6 mo. This is a relatively small study, and the follow-up period is short. A larger sample size and longer follow-up may be required. Conclusions: Although total renal function was almost unaffected before and after NSS, a warm ischemic time of >= 25 min caused irreversible damage distributed diffusely throughout the operated kidney. (C) 2008 European Association of Urology. Published by Elsevier B.V. All rights reserved.