The Use of Chemical Treatments for Improved Comminution of Artificial Stones

No AccessJournal of UrologyCLINICAL UROLOGY: Original Articles1 May 2004The Use of Chemical Treatments for Improved Comminution of Artificial Stones D. HEIMBACH, J. KOURAMBAS, P. ZHONG, J. JACOBS, A. HESSE, S.C. MUELLER, F.C. DELVECCHIO, F.H. COCKS, and G.M. PREMINGER D. HEIMBACHD. HEIMBACH More articles by this author , J. KOURAMBASJ. KOURAMBAS More articles by this author , P. ZHONGP. ZHONG More articles by this author , J. JACOBSJ. JACOBS More articles by this author , A. HESSEA. HESSE More articles by this author , S.C. MUELLERS.C. MUELLER More articles by this author , F.C. DELVECCHIOF.C. DELVECCHIO More articles by this author , F.H. COCKSF.H. COCKS More articles by this author , and G.M. PREMINGERG.M. PREMINGER More articles by this author View All Author Informationhttps://doi.org/10.1097/01.ju.0000118962.31123.fdAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract Purpose: The acoustic and mechanical properties of various stone compositions are significantly different and thus result in varying degrees of fragility. Consequently, results to shock wave lithotripsy (SWL) are influenced accordingly. We report the results of a study of fragility of various stone compositions, and the influence on each stone's baseline physical properties and fragility when exposed to various chemolytic solutions. Materials and Methods: Before SWL artificial stones of differing compositions were irrigated with various chemolytic solutions. Calcium oxalate monohydrate (COM) stones were treated with ethylenediaminetetraacetic acid (EDTA), stones composed of magnesium ammonium phosphate hydrogen were treated with hemiacidrin, and stones made of uric acid (UA) were treated with tromethamine. Synthetic urine served as a control for all stone groups. Using an ultrasound transmission technique, longitudinal wave propagation speed was measured in all groups of artificial stones. Stone density was also measured by using a pycnometer (based on Archimedes’ principle). Based on these measurements transverse (shear) wave speed (assuming a constant Poisson’s ratio), wave impedance and dynamic mechanical properties of the artificial stones were calculated. Moreover, the microhardness of these artificial stones was measured, and fragility testing using SWL with and without pretreatment with the previously mentioned chemolytic solutions, was performed. Results: Wave speed, wave impedance, dynamic mechanical properties and microhardness of EDTA treated COM stones and tromethamine treated UA stones were found to decrease compared to untreated (synthetic urine) control groups. The suggestion that chemolytic pretreatment increases stone fragility was verified by the finding of increased stone comminution after SWL testing. Combining this medical pretreatment and SWL, the findings demonstrate a significant impact of various solvents on stone comminution, in particular EDTA treated COM stones, tromethamine treated UA stones and hemiacidrin treated magnesium ammonium phosphate hydrogen stones. These data suggest that by altering the chemical environment of the fluid surrounding the stones it is possible to increase the fragility of renal calculi in vitro. Conclusions: These results indicate that appropriate chemical treatments may provide a useful adjunctive modality for improving the efficacy of stone comminution during shock wave lithotripsy. References 1 : Acoustic and mechanical properties of renal calculi: implications in shock wave lithotripsy. J Endourol1993; 7: 437. Google Scholar 2 : Effect of pH on the microhardness of renal calculi. J Biomed Mater Res1986; 20: 945. Google Scholar 3 : Extracorporeal shock wave lithotripsy: the use of chemical treatments for improved stone comminution. J Urol1987; 138: 1295. Abstract, Google Scholar 4 : Dissolution of artificial (natural) stones in a standard model: first results. J Endourol1997; 11: 63. Google Scholar 5 : A continuous wave technique for the measurement of the elastic properties of cortical bone. J Biomech1984; 17: 349. Google Scholar 6 : Urease. The primary cause of infection-induced urinary stones. Invest Urol1976; 13: 346. 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Edited by . Philadelphia: Lippincott-Raven Publishers1996: 529. Google Scholar From the Department of Urology, Section of Experimental Urology, University of Bonn, Bonn, Germany, the Departments of Mechanical Engineering and Materials Science (PZ, FHC) and Urology (JK, FCD, GMP), and the Comprehensive Kidney Stone Center, Duke University Medical Center, Durham, North Carolina© 2004 by American Urological Association, Inc.FiguresReferencesRelatedDetails Volume 171Issue 5May 2004Page: 1797-1801 Advertisement Copyright & Permissions© 2004 by American Urological Association, Inc.Keywordssolutionslithotripsykidney calculiMetricsAuthor Information D. HEIMBACH More articles by this author J. KOURAMBAS More articles by this author P. ZHONG More articles by this author J. JACOBS More articles by this author A. HESSE More articles by this author S.C. MUELLER More articles by this author F.C. DELVECCHIO More articles by this author F.H. COCKS More articles by this author G.M. 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