Browsing by Subject "stone fragmentation"

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    Impact of stone type on cavitation in burst wave lithotripsy
    (Acoustical Society of America, 2018-12-26) Hunter, Christopher; Maxwell, Adam D.; Cunitz, Bryan; Dunmire, Barbrina; Sorensen, Mathew D.; Williams, James C.; Randad, Akshay; Bailey, Michael; Kreider, Wayne; Anatomy and Cell Biology, School of Medicine
    Non-invasive kidney stone treatments such as shock wave lithotripsy (SWL) and burst wave lithotripsy (BWL) rely on the delivery of pressure waves through tissue to the stone. In both SWL and BWL, the potential to hinder comminution by exciting cavitation proximal to the stone has been reported. To elucidate how different stones alter prefocal cavitation in BWL, different natural and synthetic stones were treated in vitro using a therapy transducer operating at 350 kHz (peak negative pressure 7 MPa, pulse length 20 cycles, pulse repetition frequency 10 Hz). Stones were held in a confined volume of water designed to mimic the geometry of a kidney calyx, with the water filtered and degassed to maintain conditions for which the cavitation threshold (in the absence of a stone) matches that from in vivo observations. Stone targeting and cavitation monitoring were performed via ultrasound imaging using a diagnostic probe aligned coaxially with the therapy transducer. Quantitative differences in the extent and location of cavitation activity were observed for different stone types—e.g., “softer” stones (natural and synthetic) that disintegrate into “dusty” fragments produced larger prefocal cavitation clouds. Future work will focus on correlation of such cavitation metrics with stone fragmentation.
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    Randomized controlled trial comparing three different modalities of lithotrites for intracorporeal lithotripsy in pcnl
    (Liebert, 2017) York, Nadya E.; Borofsky, Michael S.; Chew, Ben H.; Dauw, Casey A.; Paterson, Ryan F.; Denstedt, John D.; Razvi, Hassan; Nadler, Robert B.; Humphreys, Mitchell R.; Preminger, Glenn M.; Nakada, Stephen Y.; Krambeck, Amy E.; Miller, Nicole L.; Terry, Colin; Rawlings, Lori D.; Lingeman, James E.; Department of Urology, School of Medicine
    Purpose: To compare the efficiency (stone fragmentation and removal time) and complications of three models of intracorporeal lithotripters in percutaneous nephrolithotomy (PCNL). Materials and Methods: Prospective, randomized controlled trial at nine centers in the North America from 2009 to 2016. Patients were randomized to one of three lithotripter devices: the Cyberwand, a dual probe ultrasonic device; the Swiss Lithoclast Select, a combination pneumatic and ultrasonic device; and the StoneBreaker, a portable pneumatic device powered by CO2 cartridges. Since the StoneBreaker lacks an ultrasonic component, it was used with the LUS‐II ultrasonic lithotripter to allow fair comparison with combination devices. Results: 270 patients were enrolled, 69 were excluded after randomization. 201 patients completed the study: 71 in the Cyberwand group, 66 in the Lithoclast Select, and 64 in the StoneBreaker group. The baseline patient characteristics of the three groups were similar. Mean stone surface area was smaller in the StoneBreaker group at 407.8mm2 vs 577.5mm2 (Lithoclast Select) and 627.9mm2 (Cyberwand). The stone clearance rate was slowest in the StoneBreaker group at 24.0 mm2/min vs 28.9 mm2/min and 32.3 mm2/min in the Lithoclast Select and Cyberwand groups respectively. After statistically adjusting for the smaller mean stone size in the StoneBreaker group, there was no difference in the stone clearance rate among the three groups (p=0.249). Secondary outcomes, including complications and stone free rates, were similar between the groups. Conclusions: The Cyberwand, Lithoclast Select, and the StoneBreaker lithotripters have similar adjusted stone clearance rates in PCNL for stones > 2cm. The safety and efficacy of these devices are comparable.