title: Enhanced High-Rate Shockwave Lithotripsy Stone Comminution in an In Vivo Porcine Model Using Acoustic Bubble Coalescence.
abstract: Cavitation plays a significant role in the efficacy of stone comminution during shockwave lithotripsy (SWL). Although cavitation on the surface of urinary stones helps to improve fragmentation, cavitation bubbles along the propagation path may shield or block subsequent shockwaves (SWs) and potentially induce collateral tissue damage. Previous in vitro work has shown that applying low-amplitude acoustic waves after each SW can force bubbles to consolidate and enhance SWL efficacy. In this study, the feasibility of applying acoustic bubble coalescence (ABC) in vivo was tested. Model stones were percutaneously implanted and treated with 2500 lithotripsy SWs at 120 SW/minute with or without ABC. Comparing the results of stone comminution, a significant improvement was observed in the stone fragmentation process when ABC was used. Without ABC, only 25% of the mass of the stone was fragmented to particles <2 mm in size. With ABC, 75% of the mass was fragmented to particles <2 mm in size. These results suggest that ABC can reduce the shielding effect of residual bubble nuclei, resulting in a more efficient SWL treatment.
authors.affiliation: 1 Department of Biomedical Engineering, University of Michigan , Ann Arbor, Michigan.
authors.forename: Hedieh
authors.initials: H
authors.lastname: Alavi Tamaddoni
authors.affiliation: 2 Department of Urology and Biomedical Engineering, University of Michigan , Ann Arbor, Michigan.
authors.forename: William W
authors.initials: WW
authors.lastname: Roberts
authors.affiliation: 3 HistoSonics, Inc. , Ann Arbor, Michigan.
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Duryea
authors.affiliation: 1 Department of Biomedical Engineering, University of Michigan , Ann Arbor, Michigan.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Cain
authors.affiliation: 1 Department of Biomedical Engineering, University of Michigan , Ann Arbor, Michigan.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Hall
mesh_terms: D000162:Acoustics; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy; D013552:Swine; D014159:Transducers; D014545:Urinary Calculi / Q000628:therapy*
keywords: acoustic bubble coalescence; extracorporeal shock wave lithotripsy; high rate SWL; in vivo; renal stone; shielding effect