BWL plus ultrasonic propulsion shows safety, efficacy for small renal stones

Combination treatment with burst wave lithotripsy (BWL) and ultrasonic propulsion was shown to be an effective and safe method of removing small, asymptomatic renal stones in awake patients in a clinic setting, according to recent findings published in Journal of Urology.¹

Jonathan D. Harper, MD

“Burst wave lithotripsy is a new noninvasive way to fragment stones. Ultrasonic propulsion is a way to non-invasively reposition the fragments from the kidney to the ureter so they pass,” explained lead author Jonathan D. Harper, MD, in correspondence with Urology Times®. “Both are done with awake patients in the office or emergency department—no anesthesia, sedation or medications, and no stents. Both can be done with 1 machine and 1 probe, just [by] pushing a button to swap between the 2 treatments.”

He added, “Here, we focused on treating small (2 mm to 7 mm) renal stones that were not indicated for surgery yet but could be considered a ticking time-bomb.”

In total, 20 patients with 31 stones received the procedure. Of those, 7 patients underwent a repeat procedure.

Data showed that the primary effectiveness outcome of no fragment greater than 2 mm was achieved in 22 of 31 stones (71%) treated. Additionally, 17 of 31 stones (55%) were stone-free following treatment. The median reduction in stone volume was 100% (IQR, 88% to 100%).

Participants in the study also completed the Wisconsin Stone Quality-of-Life (WISQOL) questionnaire at 90 days prior to and 120 days after the procedure. WISQOL scores improved from baseline in 10 of 15 completed questionnaires.

Regarding safety, all adverse events (AEs) were grade I.

Matthew D. Sorensen, MD, MS, FACS

“All tolerated the treatment,” said senior author Matthew D. Sorensen, MD, MS, FACS, in correspondence with Urology Times. “No one returned unexpectedly for additional care such as obstruction or pain. Adverse events were minimal.”

Previous data

These findings support previous work on the safety and efficacy of BWL and ultrasonic propulsion for stone therapy.

Data from a prospective study (NCT03811171) published in 2024 in the Journal of Urology, for example, demonstrated that BWL was safe and effective approach to fragmenting urinary stones.² Among the 44 patients included in the study, stone fragmentation occurred in 88% of cases. Of those, 70% had fragments of 4mm or less and 51% had fragments of 2mm or less on CT. Additionally, 49% were rendered stone free.

No serious AEs were reported.

Further, combination treatment with BWL and ultrasonic propulsion demonstrated efficacy in a 2022 study published in Journal of Urology.³ The study included 29 patients, of whom 16 underwent ultrasonic propulsion alone and 13 underwent ultrasonic propulsion with BWL. Overall, 86% (18 of 21) of stones were passed among those with distal ureteral stones. Fragmentation was observed in 7 of the patients who also received BWL.

Adverse events included hematuria on initial urination post-procedure and mild pain.

On future directions for this combination approach, Sorensen added, “The FDA has cleared the first ultrasonic propulsion device which is called Stone Clear by SonoMotion. SonoMotion's BWL device Break Wave is in clinical trials in the US and Canada. SonoMotion’s aim is to develop a commercial single platform featuring both BWL and ultrasonic propulsion. We hope that means both BWL and ultrasonic propulsion will soon be available to use clinically.”

REFERENCES

1. Harper JD, Dunmire B, Thiel J, et al. Facilitated clearance of small, asymptomatic renal stones with burst wave lithotripsy and ultrasonic propulsion. J Urol. 2025:101097JU0000000000004533. Doi:10.1097/JU.0000000000004533

2. Chew BH, Harper JD, Sur RL, et al. Break wave lithotripsy for urolithiasis: Results of the first-in-human international multi-institutional clinical trial. J Urol. 2024 Oct;212(4):580-589. doi:10.1097/JU.0000000000004091

3. Hall MK, Thiel J, Dunmire B, et al. First series using ultrasonic propulsion and burst wave lithotripsy to treat ureteral stones. J Urol. 2022 Nov;208(5):1075-1082. doi:10.1097/JU.0000000000002864