[Second generation of an extracorporeal shock wave lithotripsy (Lithostar)]

Use of external shock-wave lithotripsy and adjuvant ursodiol for treatment of radiolucent gallstones. A national multicenter study

A prospective multicenter trial was performed to evaluate the use of external shockwave lithotripsy (ESL) and adjuvant medical therapy for the treatment of gallstones. A Medstone STS lithotripter was used together with ursodiol. Two hundred twenty-three patients were treated under general anesthesia (75%) or with intravenous analgesia (25%). Initial treatments were on an inpatient basis, but as centers gained experience, outpatient treatments became more common. Stone fragmentation and clearance were greatest in patients with solitary gallstones less than 2 cm in diameter. In this group of patients, stone fragmentation occurred in 97% of patients, and the cumulative stone-free rates at three and six months were 54% and 90%, respectively. These results indicate that fragmentation of gallstones can be achieved by a dry shock-wave lithotripter and that stone clearance is induced more rapidly by external shock-wave lithotripsy and adjuvant ursodiol therapy than by ursodiol therapy alone.

Electromagnetically generated extracorporeal shock waves for gallstone lithotripsy: in vitro experiments and clinical relevance

First generation shock wave sources have been proved to disintegrate gallstones effectively, but they require the immersion of the patient's body in a tank of water. A recently developed second generation shock wave source (Siemens-Lithostar, Erlangen, FRG) generates shock waves electromagnetically. It presents several novel features. In particular the waterbath can be omitted and due to lower shock wave pressure general anaesthesia is not required. In vitro studies showed that 36 out of 38 gallstones (11-30 mm in diameter) could be disintegrated. Two concrements resisting lithotripsy were pure white cholesterol stones. Independent of shape, size, and composition (cholesterol or pigment) the maximum diameter of remaining fragments after lithotripsy was between 1 and 8 mm. For sufficient disintegration precise focusing (+/- 1 cm) of the stones and maximum power of the shock wave generator were required.