CHOOSING A POWERFUL LITHOTRIPTOR

Clinicians have no yardstick to help them choose the most efficient li thotriptor. Their leading priority is a system allowing complete disin tegration of the stone with the minimum number of shocks and a low re- treatment rate. One of the prerequisites of this system is a powerful shock wave generator. ''Power'' is as yet ill defined in lithotripsy. Therefore clinicians' choice depends upon other factors. Acoustic outp ut measurements were recorded on 3 commercial lithotriptors representi ng the 3 main shock wave generating systems. These were the Dornier MP L 9000 (standard and X-155 electrodes), the Siemens (Lithostar, Lithos tar Plus and System C) and the Wolf Piezolith 2300. The shock wave mea surements were correlated to the capability of the lithotriptors to di sintegrate standard stone models in vitro. Two factors were identified . The pulse intensity integral in the focus and the size of the focal zone proved to be the most important factors to assess and compare the efficacy or ''power'' of different lithotriptors. Together they can h elp clinicians to identify and choose the most efficient shock wave ge nerating systems.