2304 IN VIVO STONE COMMINUTION PRODUCED BY A MODIFIED ACOUSTIC LENS FOR ELECTROMAGNETIC LITHOTRIPTERS (2013)

You have accessJournal of UrologyStone Disease: Basic Research (II)1 Apr 20132304 IN VIVO STONE COMMINUTION PRODUCED BY A MODIFIED ACOUSTIC LENS FOR ELECTROMAGNETIC LITHOTRIPTERS Andreas Neisius, Nathan Smith, Nicholas J. Kuntz, Tim Schykowski, Gaston M. Astroza, Ramy Youssef, Muhammad W. Iqbal, Michael E. Lipkin, Michael N. Ferrandino, Walther N. Simmons, Glenn M. Preminger, and Pei Zhong Andreas NeisiusAndreas Neisius Durham, NC More articles by this author , Nathan SmithNathan Smith Durham, NC More articles by this author , Nicholas J. KuntzNicholas J. Kuntz Durham, NC More articles by this author , Tim SchykowskiTim Schykowski Durham, NC More articles by this author , Gaston M. AstrozaGaston M. Astroza Durham, NC More articles by this author , Ramy YoussefRamy Youssef Durham, NC More articles by this author , Muhammad W. IqbalMuhammad W. Iqbal 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 , Walther N. SimmonsWalther N. 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.2013.02.2245AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The acoustic lens of a Siemens Modularis electromagnetic shock wave lithotripter has been further modified to reduce pre-focal cavitation while generating a pressure waveform and broad focal zone mimicking that of the Dornier HM3. In this study, we sought to determine the comminution efficiency of the modified lens following a clinical therapy regime and compared the results to comminution produce by the original lens in a swine model. METHODS Using the maximum energy level (E+ = 44 mJ) that is safe for lithotripsy (i.e., without formation of gross hematoma), we have compared stone comminution produced by the original and modified lenses in vivo using hard cylindrical Begostones of 5 x10 mm, surgically implemented in pig kidneys. A clinical protocol with a soft ramping scheme was used to deliver 3000 shock waves to each kidney using a pulse repetition frequency of 1.5 Hz, leading to a total accumulated energy of 112.84 J. Following lithotripsy, kidneys were harvested, dissected, all visible stone fragments were collected, dried and filtered with standard sieves with decreasing mesh size of 4, 2.8, and 2 mm, respectively. Final comminution efficiencies were determined by the percentage (by weight) of fragments less than 2 mm. An unpaired two-tailed student's t-test was used to compare fragmentation results. RESULTS At E+ = 44 mJ, the modified lens (12 renal units) showed a comminution efficiency of 72.8% (±21.4%) compared to 63.6% (±21.8%) for the original lens (10 renal units) overall, p= 0.058. When considering stones not trapped in the DJ loop and those with no spread >2cm, comminution efficiency was 88.8% (±10.9%) for the modified lens vs 54.1% (±23.3%) for the original lens, p=0.013. CONCLUSIONS With our latest lens modification the electromagnetic lithotripter demonstrates better stone comminution under a clinically relevant energy setting and treatment protocol when compared to the original lens. This lens modification could be retrofitted to most electromagnetic lithotripters, thereby improving efficiency of clinical stone fragmentation. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e944 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Andreas Neisius Durham, NC More articles by this author Nathan Smith Durham, NC More articles by this author Nicholas J. Kuntz Durham, NC More articles by this author Tim Schykowski Durham, NC More articles by this author Gaston M. Astroza Durham, NC More articles by this author Ramy Youssef Durham, NC More articles by this author Muhammad W. Iqbal 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 Walther N. 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 ...