Effect of Percutaneous Nephrolithotomy and Tract Dilatation Methods on Renal Function: Assessment by Quantitative Single-Photon Emission Computed Tomography of Technetium-99m-Dimercaptosuccinic Acid Uptake by the Kidneys

Objectives: The aim of this study was to determine the impact of percutaneous nephrolithotomy (PCNL) and tract dilatation methods on global and regional renal function using quantitative single-photon emission computed tomography (QSPECT) of technetium-99m-dimercaptosuccinic acid (Tc-99m-DMSA). Methods: Seventy-five patients undergoing PCNL between May 2008 and April 2009 were included in this randomized study. Of the 75 patients, 50 were evaluated by QSPECT of Tc-99m-DMSA examinations before and at 3 to 6 months after surgery. This group of patients were categorized into three groups according to the dilatation technique used: group I (balloon dilator, n=12 [24%] patients), group II (metal dilator, n=14 [28%] patients), and group III (Amplatz dilator, n=24 [48%] patients). Results: Of 50 renal units, new focal cortical defects on Tc-99m-DMSA scan were seen in nine patients (18%). In six of these kidneys the site of focal defect corresponded to the access site for tract formation during PCNL (two in group II and four in group III). Total relative uptake and total area of treated kidney, for the entire group, increased from 42.2% and 42.3% preoperatively to 44.12% and 43.9% postoperatively. There was no statistically significant differences between the groups for total uptake and area of the treated kidneys before and after the procedure (p>0.05 for each parameter). Conclusions: QSPECT of Tc-99m-DMSA confirms that renal function is preserved or often improved after percutaneous stone removal, and nephrostomy tract dilatation methods have similar effects on renal function.