Evaluation of Residual Stone Fragments Following Lithotripsy: Sonography v Radiography

Abernathy, Brett B.; Morris, James S.; Wilson, W. Tad; Miller, George; Preminger, Glenn M.

doi:10.1007/978-1-4757-2052-5_47

Cited by 4 publications

References 3 publications

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Lithotripsy

Weizer¹,

Preminger²

2006

Encyclopedia of Medical Devices and Instrumentation

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Shock wave lithotripsy (SWL) is a noninvasive method for the treatment of stones within the urinary tract. Since its clinical introduction over 25 years ago, SWL has revolutionized the way in which renal and ureteral stones are managed. Despite the wide array of currently available lithotripters, all rely on the same fundamentals of acoustic physics. Shock waves (i.e., high pressure sound waves) consisting of a sharp peak in positive pressure followed by a trailing negative wave are generated extracorporeally and passed through the body to fragment stones. Ultrasound or fluoroscopy are used to focus the shock wave on the stone inside the patients’ body. When the shock wave encounters the kidney stone, the force generated in the plane of the shock wave places stress on the imperfections within the stone resulting in compression‐induced tensile cracking. In addition, shock waves can cause microbubble formation on the surface of the stone. As the shock wave passes, these bubbles collapse releasing secondary shock waves or microjets impinging against the stone that result in stone destruction. While these mechanisms result in stone fragmentation, they may also be responsible for kidney injury, by primarily damaging small blood vessels within the kidney. Modifications to the design of the original lithotripter (Dornier HM3, Dornier MedTech America, Inc., Kennesaw, GA) resulted in improved patient comfort, but inferior stone fragmentation. Better understanding of the mechanisms of stone fragmentation and tissue injury caused by SWL have resulted in modifications to lithotripters that make the current machines safer and more effective.

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