Tissue damage of the extracorporeal shock wave lithotripsy(ESWL) is proven histologically in the past, but its mechanism of damage causing cellular disruption has yet to be elucidated. Our s´study is designed to investigate further the cellular. damage of ESWL using 13 normal rabbit livers and analyzing its postshock wave changes by transmission electron microscopy.
Preliminary study was performed in two rabbits for dosage determination of shock waves at a ;.,frequency of 20 shots per second, 75% power, and 100 shock wave storage with piezoelectric lithotriptor. And shock waves were administrated to group I (4 rabbits), H (4 rabbits) and III (3 rabbits) with _a frequency of 20 shots per second, 87% power, and 100, 50, 25 storage respectively
The rabbits were sacrified 6-12 hour thereafter.
Macroscopically, all livers showed subcapsular and parenchymal hemorrhage. On the other hand, the light microscopy showed multiple areas of hemorrhagic necrosis, sinusoidal congestion, portal vein thrombosis and small vein rupture in all specimens. Bile ducts were damaged only in one case of group I. Trasmissiom electron microscopy showed vacuolization and peripheral redistribution of intracellular organells with minimal structural changes at 25 and 50 storage. At 100 storage, how-ever, above pathologic changes were more profound, showing marked dilatation with structural alteration of endoplasmic reticulum, cell membrane rupture and necrosis.
Therefore, early histopathologic changes induced by shock wave is dose dependent and might be due to rupture of small veins, structural alteration and redistribution of intracellular components.
|