A prospective study evaluating impact on renal function following percutaneous nephrolithotomy using Tc99m ethylenedicysteine renal scan: Does multiplicity of access tracts play a role?

Purpose: A prospective study evaluating impact of percutaneous nephrolithotomy (PCNL) on renal function following PCNL using ethylenedicysteine (EC) renal scan. Does multiplicity of access tracts play a role? Materials and Methods: A prospective observational study was done and patients undergoing PCNL for renal calculi at our urology department were selected. Renal Tc99m EC scan was done pre-surgery and at 3 months follow-up. An assessment was done on decline in glomerular filtration rate (GFR) in postoperative period based on number of access tracts required. Results: A total of 110 patients were enrolled in the study. The total number of punctures was 170 with 141 being supra-costal puncture and 29 infra-costal. The total number of single punctures were 60 and classified as Group I whereas patients with double puncture and triple puncture (40 and 10 patients, respectively) were classified as Group II. Mean postoperative split renal function (in Tc99m EC scans) of patients of Group I (40.93 +/- 19.62%) was found to be higher than that of Group II (32.82 +/- 16.98%). Mean change (decline) in GFR for single, double and triple tracts were 2.68 mL/min, 3.80 mL/min, and 4.2 mL/min, respectively. Conclusions: PCNL used for stone removal can improve renal function by eradicating obstruction; however, this procedure may itself negatively impact the functions of the targeted kidney. Our study showed post PCNL decrease in GFR which worsens with an increasing number of accesses.