CHOOSING A POWERFUL LITHOTRIPTOR

Clinicians have no yardstick to help them choose the most efficient lithotriptor. Their leading priority is a system allowing complete disintegration 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 output measurements were recorded on 3 commercial lithotriptors representing the 3 main shock wave generating systems. These were the Dornier MPL 9000 (standard and X-155 electrodes), the Siemens (Lithostar, Lithostar Plus and System C) and the Wolf Piezolith 2300. The shock wave measurements were correlated to the capability of the lithotriptors to disintegrate 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 help clinicians to identify and choose the most efficient shock wave generating systems.