A prototype device for nonimmersion shock wave lithotripsy using ultrasonography for calculus localization.

Extracorporeal shock wave lithotripsy has revolutionized the clinical treatment of renal calculi. A device was constructed with a spark gap for shock wave generation and a water-filled ellipsoidal reflector to focus the shock wave energy. A membrane coupled the device to the pig and an ultrasonic transducer was used for stone visualization. Initial in vitro experiments and in vivo studies using dwarf pigs demonstrated fragmentation of calculi.