University Research Will Improve Lives

Major milestones were achieved in the past year by an investigative team at the Center for Industrial and Medical Ultrasound and their multi-institutional collaborators who developed ultrasonic therapies to treat kidney stones. Results of several successful clinical trials have been published and the spin-out company commercializing the University inventions has received medical device clearance from the Food and Drug Administration. "These recently published studies are the culmination of our work to invent ultrasonic therapies for kidney stones," says Senior Principal Engineer Mike Bailey. "Stones can be treated when first discovered and patients are not sent home to wait in pain and anxiety over whether they'll have more pain or surgery," adds Bailey.

The team's office-based system to visualize and treat kidney stones in awake patients uses transcutaneous, focused ultrasound waves from a handheld probe to break (burst wave lithotripsy) and push (ultrasonic propulsion) stone fragments within the kidney toward the renal pelvis and ureter to facilitate their natural passage through the urine. "The two technologies we’ve been working on are different than anything that exists currently," notes University of Washington Professor of Urology Matthew Sorensen. "This changes how patients are treated. We focus on treating any stone rather than trying to avoid surgery at the risk of painful stone passage."

Recent clinical trial results are conclusive. In one study subjects were recruited to receive treatment with ultrasonic propulsion (UP) to reposition residual stone fragments from a previous surgery. Fragment passage rate was 58% greater in the treatment group, they had a 70% lower incidence of relapse, and their time to relapse was longer by nearly 1.5 years than patients who did not receive UP. These results were duplicated in another trial conducted by an independent group of UW investigators who were novice users of the ultrasonic system. They achieved a 66% greater rate of residual fragment clearance in the UP treatment group vs. controls, and in one year of follow-up, 0 of 12 in the treatment group returned to the emergency department or operating room for their stones versus 6 of 12 in the control group. And in the first human feasibility study of burst wave lithotripsy followed by ultrasonic propulsion in a clinical setting, the investigators achieved a clearance rate of 70% for small, asymptomatic stones. In all trials, the awake participants, now totaling over 200, tolerated the procedure without anesthesia or serious adverse events.

SonoMotion, the medical device company spun off from the University of Washington inventions, has developed a single platform that can fragment stones with Break Wave and reposition stones with Stone Clear. The company received FDA 510 (k) de novo clearance for Stone Clear in late 2024 and a multicenter pivotal trial conducted in the U.S. and Canada has been completed to support clearance of Break Wave.

As the SonoMotion device appears poised to come online in clinics, Bailey describes the impact of their research and development journey. "This technology isn’t just another tool that might work better. We are proving that it can access a different set of patients." Sorensen adds that the ultrasonic system will dramatically change the way urologists approach stone treatment, resetting the bar of whether to treat or not. "Instead of deciding whether it’s worth taking someone to surgery, we can treat asymptomatic, but potentially troublesome, stones right in the clinic."