COMPARISON OF DIFFERENT LITHOTRIPTERS IN REGARD TO DISINTEGRATIVE EFFICACY (DE) AND DISINTEGRATIVE RANGE (DR) USING AN IN-VITRO STONE MODEL

The disintegration capacity of shock wave sources plays an important p art in the clinical efficacy of lithotripters. We endeavoured to asses s the disintegrative efficacy and range of diverse shock wave generato rs by means of an established, standardized in vitro stone model. An a rtificial stone was focussed in a wire mesh and then disintegrated by shock waves (SW) until all fragments passed through the mesh. The reci procal value of the required number of SW corresponded to the disinteg rative efficacy (DE = 100/SW). The disintegrative range was calculated between minimum and maximum generator voltage (DR = DE(min) - DE(max) ). These parameters varied distinctly between the electrohydraulic (Do rnier HM 3, MPL 9000), electromagnetic (Storz Medical Modulith SL, Sie mens Lithostar Plus undercouch- and overhead-module) and piezoelectric (Wolf Piezolith 2500 and 2300, EDAP LT02) generators tested. The corr elation between SW and generator voltage enabled the determination of typical central lines for these machines. The Modulith SL, followed by both the electrohydraulic lithotripters, MPL 9000 and HM 3 demonstrat ed the highest disintegrative efficacy. The widest range was achieved by the piezoelectric lithotripters as well as the Lithostar undercouch module and the Modulith. The DE value for the generator voltage appli ed in clinical kidney stone lithotripsy was concurrent for the various SW sources between 0.2 and 0.9. The EDAP LT02 demonstrated inferior e fficacy and therefore requires an alternative treatment strategy. Howe ver, there were distinct differences in output reserve in the high- an d low-energy ranges, which are desirable for a wide spectrum of clinic al indications.