Histomorphologic and ultrastructural findings of shockwave-induced lesions in the isolated perfused kidney of the pig.

The aim of this investigation was the development of an easily reproducible model with which to evaluate shockwave-induced renal tissue damage using light and electron microscopy. Kidneys (n = 45) from freshly slaughtered pigs were perfused under physiologic conditions and treated with shockwaves at different doses (2-250 shockwaves; 12-20 kV) on the Modulith SL 20 lithotripter. The dose-dependent alterations in tissue structure were characterized by disintegration of tubular cells leading to circumscribed gap-like defects resulting from reticular fiber disruptions. Even after low shockwave doses, cellular and subcellular alterations could be observed. Our findings in this ex vivo model verify the development of considerable strictly localized, dose-dependent shockwave-induced damage of the renal parenchyma. On morphologic grounds, we cannot confirm a primary lesion or rupture of blood vessel walls as the cause of the shockwave lesions. The destruction of tubular cells in combination with disruption of peritubular and pericapillary reticular fiber coats results in capillarotubular leaks, which can explain even severe transitory macrohematuria after clinical shockwave lithotripsy without renal hematoma formation.