Shock wave lithotripsy can alter urinary acid-base pH regulation.

The renal papilla is particularly susceptible to injury by shock waves (SWs). Since the papilla is vital for urinary pH regulation, we hypothesized that shock wave lithotripsy (SWL)-induced damage of papillae will alter the pH of the urine. Experiments were conducted in four female adult Gottingen minipigs. The HM3 lithotripter delivered a total of 8000 SWs (24 kV, 120 SWs/min) among all papillae of one kidney, while the untreated, opposite kidney was used as control. The pigs were allowed to recover and 5 weeks later they were anesthetized. Serial urine collections were obtained from the SW-treated and untreated kidney. Urine was collected under mineral oil and immediately tested for its pH. Both kidneys were then perfusion fixed for histological analysis. Urinary pH was 0.17 units greater (P<0.05) in the SW-treated kidney compared to the untreated kidney. Histology showed scarring in all regions of the SW-treated kidney, with thick ascending limbs and collecting ducts having grossly abnormal morphologies indicative of cellular proliferation. These results suggest that SWL-induced injury can cause remodeling of nephron structures and long-term impairment in the regulation of urinary pH.