Effect of multiple access tracts during percutaneous nephrolithotomy on renal function: evaluation of risk factors for renal function deterioration

To assess the impact of multiple access tracts during percutaneous nephrolithotomy (PCNL) on short- and midterm renal function, and to determine risk factors predicting renal function deterioration and/or recoverability. Patients undergoing PCNL with multiple punctures were prospectively enrolled. Preoperative evaluation included dimercaptosuccinic acid and diethylenetriaminepentaacetic acid renography. Patients were classified according to baseline renal function into patients with normal (