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Ramesh S, Chen TT, Maxwell AD, Cunitz BW, Dunmire B, Thiel J, Williams JC, Gardner A, Liu Z, Metzler I, Harper JD, Sorensen MD, Bailey MR. In Vitro Evaluation of Urinary Stone Comminution with a Clinical Burst Wave Lithotripsy System. J Endourol 2020; 34:1167-1173. [PMID: 32103689 DOI: 10.1089/end.2019.0873] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Objective: Our goals were to validate stone comminution with an investigational burst wave lithotripsy (BWL) system in patient-relevant conditions and to evaluate the use of ultrasonic propulsion to move a stone or fragments to aid in observing the treatment endpoint. Materials and Methods: The Propulse-1 system, used in clinical trials of ultrasonic propulsion and upgraded for BWL trials, was used to fragment 46 human stones (5-7 mm) in either a 15-mm or 4-mm diameter calix phantom in water at either 50% or 75% dissolved oxygen level. Stones were paired by size and composition, and exposed to 20-cycle, 390-kHz bursts at 6-MPa peak negative pressure (PNP) and 13-Hz pulse repetition frequency (PRF) or 7-MPa PNP and 6.5-Hz PRF. Stones were exposed in 5-minute increments and sieved, with fragments >2 mm weighed and returned for additional treatment. Effectiveness for pairs of conditions was compared statistically within a framework of survival data analysis for interval censored data. Three reviewers blinded to the experimental conditions scored ultrasound imaging videos for degree of fragmentation based on stone response to ultrasonic propulsion. Results: Overall, 89% (41/46) and 70% (32/46) of human stones were fully comminuted within 30 and 10 minutes, respectively. Fragments remained after 30 minutes in 4% (1/28) of calcium oxalate monohydrate stones and 40% (4/10) of brushite stones. There were no statistically significant differences in comminution time between the two output settings (p = 0.44), the two dissolved oxygen levels (p = 0.65), or the two calyx diameters (p = 0.58). Inter-rater correlation on endpoint detection was substantial (Fleiss' kappa = 0.638, p < 0.0001), with individual reviewer sensitivities of 95%, 86%, and 100%. Conclusions: Eighty-nine percent of human stones were comminuted with a clinical BWL system within 30 minutes under conditions intended to reflect conditions in vivo. The results demonstrate the advantage of using ultrasonic propulsion to disperse fragments when making a visual determination of breakage endpoint from the real-time ultrasound image.
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Affiliation(s)
- Shivani Ramesh
- Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, University of Washington, Seattle, Washington, USA
| | - Tony T Chen
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Adam D Maxwell
- Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, University of Washington, Seattle, Washington, USA.,Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Bryan W Cunitz
- Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, University of Washington, Seattle, Washington, USA
| | - Barbrina Dunmire
- Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, University of Washington, Seattle, Washington, USA
| | - Jeff Thiel
- Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, University of Washington, Seattle, Washington, USA
| | - James C Williams
- Department of Anatomy, Cell Biology and Physiology and Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Anthony Gardner
- Department of Anatomy, Cell Biology and Physiology and Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ziyue Liu
- Department of Biostatistics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ian Metzler
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Jonathan D Harper
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Mathew D Sorensen
- Division of Urology, VA Puget Sound Health Care System, Seattle, Washington, USA
| | - Michael R Bailey
- Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, University of Washington, Seattle, Washington, USA.,Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
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