Facilitated Clearance of Small, Asymptomatic Renal Stones With Burst Wave Lithotripsy and Ultrasonic Propulsion.

Abstract

We tested feasibility of burst wave lithotripsy and ultrasonic propulsion to noninvasively fragment and expel small, asymptomatic renal stones in awake participants. Adult patients suspected of having 2- to 7-mm stones were consented and screened for eligibility. Burst wave lithotripsy and ultrasonic propulsion were applied to up to 3 stones in 1 kidney of qualifying participants for a 30-minute total exposure. Participants completed a CT scan and the Wisconsin Stone Quality-of-Life (WISQOL) questionnaire within 90 days before and 120 days after the procedure. Participants were contacted weekly for 3 weeks after the procedure to assess adverse events (AEs). Outcomes included (1) no fragment > 2 mm, (2) unanticipated health care visits, (3) change in stone volume, (4) reported AEs, and (5) WISQOL score. Forty-one participants were enrolled between April 2023 and October 2024. Twenty-one participants failed screening because no stones were seen, stones were too large or small, stone visibility was too deep or obstructed, or they declined to participate. Twenty participants with 31 stones received the research procedure with 7 undergoing a single repeat procedure. Twenty-two of 31 stones (71%) met the primary effectiveness outcome of no fragment > 2 mm, with 17 of 31 stones (55%) reported as stone free. Median stone volume reduction (IQR) was 100% (88%-100%). No participants returned unexpectedly for care related to the procedure. AEs were all grade I by modified Clavien classification. WISQOL scores improved on 10 of 15 completed questionnaires. Small, asymptomatic renal stones were effectively and safely removed in awake participants in a clinic setting.