Experimental and Clinical Experiences with Extracorporeal Shock Wave Lithotripsy with Lithocut

Abstract

A new generator for extracorporeal shock wave lithotripsy—Lithocut—utilizes the spark gap technique but has filters to modify the frequency content of the wave in order to minimize pain and reduce electrode tip wear. Induction of the shock wave is triggered by the R-wave in the ECG but starts in the end-expiratory phase to minimize focusing errors caused by renal movement. The total time of exposure to high pressure is brief, as is the time needed to fragment a stone, because of the very rapid rise and short duration of the shock wave. The method has been used on 139 calculi in 102 patients. Most were treated as outpatients, as only intravenous analgesia was required. Fragmentation was observed immediately after treatment in 86% of the stones, and after 3 months, 68% of the renal and 63% of the ureteral stones had disappeared at radiographic examination. Fragments 5 mm or larger remained from only 14% and 29% of these kinds of calculi, respectively.