1277 IN VITRO EFFICACY OF HOLMIUM:YAG LASER LITHOTRIPSY IN NON FLOATING STONES. - EFFECT OF PULSE FREQUENCY, ENERGY AND LENGTH -

Abstract

You have accessJournal of UrologyTechnology & Instruments: Ureteroscopy1 Apr 20101277 IN VITRO EFFICACY OF HOLMIUM:YAG LASER LITHOTRIPSY IN NON FLOATING STONES. - EFFECT OF PULSE FREQUENCY, ENERGY AND LENGTH - Felix Wezel, Christoph Hammes, Axel Haecker, Patrick Krombach, Maurice Stephan Michel, and Thorsten Bach Felix WezelFelix Wezel More articles by this author , Christoph HammesChristoph Hammes More articles by this author , Axel HaeckerAxel Haecker More articles by this author , Patrick KrombachPatrick Krombach More articles by this author , Maurice Stephan MichelMaurice Stephan Michel More articles by this author , and Thorsten BachThorsten Bach More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.848AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Holmium:YAG (Ho:Yag) laser lithotripsy is the gold standard in endoscopic stone treatment. Aim of this study was to evaluate the influence of pulse frequency, power and length on the effectiveness of Ho:Yag laser lithotripsy using two different artificial stone compositions in-vitro. METHODS Three different Ho:Yag laser devices (Sphinx, RevolixDuo (both LisaLaser, Germany) and Odyssey 30 (Cook, Ireland) were tested. The devices were used at different pulse energy rates (1 and 2 Joule) and frequency settings (5 and 10 Hz) all resulting in an output power of 10W, respectively. Where possible (Sphinx and Odyssey 30), pulse length was modified (350 vs. 700 msec). The light was transmitted via flexible 365μm fibers. Experiments were performed in a water bath using cone shaped artificial stone (20ml volume) consisting of a soft stone composition (plaster of paris; Quick-mix, Germany) and a hard stone composition (Fujirock type 4 dental stone; GC Europe, Belgium). Lithotripsy was performed for 60 sec in contact mode on fixed stones applying 600 W in total per setting. Stones were dried for 72 h; fine granulated sand was used to measure the volume of the craters. Sample size was n=10 for all settings using hard stones, and n=6 when using soft stones. Unpaired t-test was used for statistical analysis. RESULTS In all of the 5 tested groups per stone type, a slower pulse rate but increased pulse energy (5 Hz/ 2 J vs. 10 Hz/1 J) resulted in a higher stone disintegration. At 5 Hz/ 2 J Ho:Yag laser lithotripsy was more effective applied on hard stones (+ 27.46% (10-55.4%); all p < 0.05) and on soft stones (+ 33.62% (8-54.3%); 3 of 5 tested groups p < 0.05) compared to the 10 Hz/ 1 J setting. Furthermore, reduction of the pulse length from 700 to 350 msec resulted in a significantly higher stone disintegration (+ 71.58% (57-120.6%); all p < 0.05) in soft stone composition in 4 tested groups. In hard stone composition, reducing the pulse length was associated with a significant higher stone disintegration (+ 27.25% (23.8-30.7%); all p < 0.05) in combination with higher pulse energy (2 J/ 5 Hz). At lower pulse energy (1 J/ 10 Hz), the increased stone disintegration rate was not significant (+ 6,5% (6.4-6.5%), p > 0.05, respectively). CONCLUSIONS Our results indicate that higher pulse energy and shorter pulse length increase disintegration rates of Holmium:YAG laser lithotripsy when retropulsion is excluded in vitro. This may help to improve efficacy of Holmium:YAG laser lithotripsy in non floating stones in vivo. Mannheim, Germany© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e495 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Felix Wezel More articles by this author Christoph Hammes More articles by this author Axel Haecker More articles by this author Patrick Krombach More articles by this author Maurice Stephan Michel More articles by this author Thorsten Bach More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...