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Urology. 2014 Aug;84(2):484-9. doi: 10.1016/j.urology.2014.04.041. Epub 2014 Jun 26.

Preclinical safety and effectiveness studies of ultrasonic propulsion of kidney stones.

Author information

1
Department of Urology, University of Washington School of Medicine, Seattle, WA. Electronic address: jdharper@uw.edu.
2
Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA.
3
Department of Comparative Medicine, University of Washington School of Medicine, Seattle, WA.
4
Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
5
Department of Urology, University of Washington School of Medicine, Seattle, WA.
6
Department of Urology, University of Washington School of Medicine, Seattle, WA; Division of Urology, Department of Veteran Affairs Medical Center, Seattle, WA.

Abstract

OBJECTIVE:

To provide an update on a research device to ultrasonically reposition kidney stones transcutaneously. This article reports preclinical safety and effectiveness studies, survival data, modifications of the system, and testing in a stone-forming porcine model. These data formed the basis for regulatory approval to test the device in humans.

MATERIALS AND METHODS:

The ultrasound burst was shortened to 50 ms from previous investigations with 1-s bursts. Focused ultrasound was used to expel 2- to 5-mm calcium oxalate monohydrate stones placed ureteroscopically in 5 pigs. Additionally, de novo stones were imaged and repositioned in a stone-forming porcine model. Acute safety studies were performed targeting 2 kidneys (6 sites) and 3 pancreases (8 sites). Survival studies followed 10 animals for 1 week after simulated treatment. Serum and urine analyses were performed, and tissues were evaluated histologically.

RESULTS:

All ureteroscopically implanted stones (6/6) were repositioned out of the kidney in 14 ± 8 minutes with 13 ± 6 bursts. On average, 3 bursts moved a stone more than 4 mm and collectively accounted for the majority of relocation. Stones (3 mm) were detected and repositioned in the 200-kg stone-forming model. No injury was detected in the acute or survival studies.

CONCLUSION:

Ultrasonic propulsion is safe and effective in the porcine model. Stones were expelled from the kidney. De novo stones formed in a large porcine model were repositioned. No adverse effects were identified with the acute studies directly targeting kidney or pancreatic tissue or during the survival studies indicating no evidence of delayed tissue injury.

PMID:
24975708
PMCID:
PMC4304777
DOI:
10.1016/j.urology.2014.04.041
[Indexed for MEDLINE]
Free PMC Article

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