PURPOSE: Focused ultrasound has the potential to expel small stones or residual stone fragments from the kidney, or move obstructing stones to a non-obstructing location.
The purpose of this study was to evaluate the efficacy and safety of ultrasonic propulsion in a live porcine model.
MATERIAL AND METHODS: Calcium oxalate monohydrate kidney stones and laboratory model stones (2-8 mm) were ureteroscopically implanted within the renal pelvicalyceal system of 12 kidneys in eight domestic swine. Transcutaneous ultrasonic propulsion was performed using a Philips HDI C5-2 imaging transducer and Verasonics diagnostic ultrasound platform. Successful stone relocation was defined as stone movement from the calyx to the renal pelvis, ureteropelvic junction (UPJ) or proximal ureter. Efficacy and procedure time were determined. Three blinded experts evaluated for histologic injury to the kidney in control, sham, and treatment arms.
RESULTS: All stones were observed to move during treatment, and 65% (17/26) were relocated successfully to the renal pelvis (3), UPJ (2), or ureter (12). Average successful procedure time was 14±8 min and required 23±16 ultrasound bursts of ~1 sec duration. There was no evidence of gross or histologic injury to the renal parenchyma in kidneys exposed to 20 bursts (1 sec duration, 33 sec intervals) at the same output (2400 W/cm2) used to push stones.
CONCLUSIONS: Non-invasive transcutaneous ultrasonic propulsion is a safe, effective, and time-efficient means to relocate calyceal stones to the renal pelvis, UPJ, or ureter. This technology holds promise as a useful adjunct to the surgical management of renal calculi.
Written by:
Harper JD, Sorensen MD, Cunitz BW, Wang YN, Simon JC, Starr F, Paun M, Dunmire B, Liggitt HD, Evan AP, McAteer JA, Hsi RS, Bailey MR. Are you the author?
Department of Urology, University of Washington School of Medicine, 1959 NE Pacific Street, Seattle, WA 98195.
Reference: J Urol. 2013 Apr 9. pii: S0022-5347(13)04029-9.
doi: 10.1016/j.juro.2013.03.120
PubMed Abstract
PMID: 23583535
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