2080 ASSESSING THE EFFECTS OF RESPIRATORY MOTION ON STONE COMMINUTION DURING SHOCK WAVE LITHOTRIPSY (SWL) IN AN IN VITRO MODEL

Abstract

You have accessJournal of UrologyStone Disease: Basic Research I1 Apr 20122080 ASSESSING THE EFFECTS OF RESPIRATORY MOTION ON STONE COMMINUTION DURING SHOCK WAVE LITHOTRIPSY (SWL) IN AN IN VITRO MODEL Muhammad W. Iqbal, Agnes J. Wang, Nathan B. Smith, Gregory T. Baldwin, Gastón M. Astroza, Zachariah G. Goldsmith, F. Hadley Cocks, Michael E. Lipkin, Michael N. Ferrandino, W. Neal Simmons, Glenn M. Preminger, and Pei Zhong Muhammad W. IqbalMuhammad W. Iqbal Durham, NC More articles by this author , Agnes J. WangAgnes J. Wang Durham, NC More articles by this author , Nathan B. SmithNathan B. Smith Durham, NC More articles by this author , Gregory T. BaldwinGregory T. Baldwin Durham, NC More articles by this author , Gastón M. AstrozaGastón M. Astroza Durham, NC More articles by this author , Zachariah G. GoldsmithZachariah G. Goldsmith Durham, NC More articles by this author , F. Hadley CocksF. Hadley Cocks Durham, NC More articles by this author , Michael E. LipkinMichael E. Lipkin Durham, NC More articles by this author , Michael N. FerrandinoMichael N. Ferrandino Durham, NC More articles by this author , W. Neal SimmonsW. Neal Simmons Durham, NC More articles by this author , Glenn M. PremingerGlenn M. Preminger Durham, NC More articles by this author , and Pei ZhongPei Zhong Durham, NC More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2246AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Various methods have been employed to improve stone comminution during SWL. We evaluated the effects of respiratory motion in an in vitro model with an electromagnetic lithotripter, incorporating both an original acoustic focusing lens and a newer lens modified to have a focal size that better resembles that of the Dornier HM3. METHODS Spherical Bego Stone phantoms (44 trials with each lens) 1 cm in diameter were placed in a flat-based cylindrical tube holder attached to a translational stage and set into translational motion with various excursion distances (D), representing kidney displacement, with D = 15mm representing normal respiration and D = 30mm representing deep respiration. Three respiratory rates representative of slow, fast , and very fast breathing were chosen along with various drift factors. The Siemens electromagnetic lithotripter was aligned to focus stone at the superior position representing the kidney position at expiratory pause. Each stone treatment consisted of 2000 shock waves delivered with two different acoustic lenses, the standard and the novel with large focal size resembling that of Dornier HM3 with equivalent energies. RESULTS In 4 of 6 configurations tested with low drift, the new lens statistically improved stone comminution (p<0.01) compared to the original lens design. Comparing single lens results for different respiratory motion patterns, an excursion distance of D = 30 mm resulted in statistically lower comminution (p < 0.01) than D = 15 mm for all cases except for high drift respiration using the new lens. An increase in breathing rate from 12 to 24 Breaths per min resulted in statistically lower comminution for both lenses (p<0.01). CONCLUSIONS Comminution efficiency has a strong dependence on excursion distance, respiratory rate, and stone drift. A new acoustic lens with a wider focal zone provided better stone comminution despite differences in respiratory rate or excursion. Further in vivo studies are needed to determine if these results translate into improved clinical outcomes. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e838 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Muhammad W. Iqbal Durham, NC More articles by this author Agnes J. Wang Durham, NC More articles by this author Nathan B. Smith Durham, NC More articles by this author Gregory T. Baldwin Durham, NC More articles by this author Gastón M. Astroza Durham, NC More articles by this author Zachariah G. Goldsmith Durham, NC More articles by this author F. Hadley Cocks Durham, NC More articles by this author Michael E. Lipkin Durham, NC More articles by this author Michael N. Ferrandino Durham, NC More articles by this author W. Neal Simmons Durham, NC More articles by this author Glenn M. Preminger Durham, NC More articles by this author Pei Zhong Durham, NC More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...