Martov A, Gudkov A, Diamant V, Chepovetsky G, Lerner M
Department of Urology, Federal Medical and Biological Agency , Moscow, Russia

Abstract

PURPOSE: To compare the effectiveness of novel nanosecond electropulse lithotripsy with standard electrohydraulic lithotripsy in order to demonstrate and authenticate their differences because both modalities appear to be similar.

MATERIAL AND METHODS: An in-vitro fragmentation study was conducted using cuboid BegoStone phantoms, which mimic hard and soft stones based on an established model. Three different stone sizes were used in the testing having volumes of 100, 256 and 320 mm3. A nanosecond electropulse lithotripter (NEPL) and an electrohydraulic lithotripter (EHL) were operated using a range of probe sizes at comparable energy settings and pulse rates with the objective of obtaining a stone fragment size of less than 2 mm. In order to compare the efficacy of these two lithotripters, the number of pulses required for stone phantom fragmentation was recorded according to probe size and energy setting, which were then converted into units of cumulative energy.

RESULTS: The results clearly demonstrated that, for all operating modes and stone phantom types, the NEPL device requires much less cumulative energy and thus fewer pulses and consequently less time to achieve stone fragmentation than the EHL device. The disparity in the results is explained by the dissimilar mechanisms at work in the compared lithotripters during destruction of the stone. The electropulse stone disintegration mechanism transfers energy directly into the stone due to discharge penetration into a solid body. This contrasts with the electrohydraulic mechanism in EHL in which energy is transferred through the liquid medium, which also creates a damaging shock wave.

CONCLUSIONS: The findings demonstrate that, for all operating modes and stone types, NEPL device requires much less cumulative energy and thus fewer pulses for stone fragmentation than EHL device. The disparity in the results is explained by the dissimilar mechanisms at work in the compared lithotripters during destruction of the stone.

J Endourol. 2014 Jan 24. [Epub ahead of print]
PMID:24313364[PubMed - as supplied by publisher]