Acute effects of percutaneous tract dilation on renal function and structure

Background: Percutaneous nephrolithotomy (PCNL) is performed on a routine basis for the rapid and efficient removal of large caliceal stones. After percutaneous puncture, rigid dilators or an inflatable balloon are used to dilate the nephrostomy tract to allow access to the collecting system for stone removal. Little is known of the acute impact of tract dilation procedures on renal function. Materials and Methods: We compared renal hemodynamic and excretory function in female pigs immediately before and up to 5 hours after percutaneous nephrostonny (PCN) using sequential Amplatz dilators (N = 8) or Nephromax balloon inflation (N = 7) and control pigs with no PCN access (N = 8). We also examined renal function in patients undergoing PCNL. Results: The two PCN procedures produced a renal lesion of comparable size and morphology, as well as similar changes in renal function. Glomerular filtration rate (GFR), renal plasma flow (RPF), and urinary sodium excretion (UNaV) were significantly reduced in Amplatz- and Nephromax-treated kidneys throughout the 5-hour observation period, by about 50%, 60%, and 80%, respectively. In control pigs, GFR and RPF remained stable and UNaV declined progressively to about 50% of baseline over the course of the experiment. The contralateral kidney showed changes in renal function similar to those in the PCN-treated or control kidney in all three groups. A retrospective analysis of 196 adults with normal renal function who underwent unilateral PCNL using the Nephromax balloon dilator revealed a significant increase in serum creatinine of 0.14 mg/dL at 1 day. Conclusion: Both animal and human studies show that PCN is associated with an acute decline in renal function.