Have you ever had a ureter stone? Ureter stones are kidney stones that are trapped in the tube between the kidney and the bladder. If so, you likely experienced significant pain and needed emergency care. At the emergency room, most patients with a ureter stone are advised to wait a few days or even weeks to see if the stone passes and resolves on its own. 

To help bring patients faster relief, the University of Washington School of Medicine (UW Medicine) is researching a non-invasive ultrasound technique to treat ureter stones. Learn more about the benefits of this technique and what researchers have found.* 

What are kidney stones?

Nearly one in every 20 people will have a kidney stone in their lifetime. Stones form when crystal-forming minerals in your kidneys become too abundant and become fused together, hardening into stones. There are multiple types made of different minerals. Calcium kidney stones are the most common and are often seen in patients with chronic kidney disease (CKD). 

What is the new technique to treat ureter stones?

In the new procedure being tested by UW Medicine, a physician places a handheld device, called a transducer, on the skin where ultrasound waves can be used to move, reposition, or break up the stone. The process of moving or repositioning stones is called ultrasound propulsion, while the process of breaking up a stone is called burst wave lithotripsy (BWL). 

Unlike the standard procedure used currently, the new technology does not require sedation and does not hurt. Lead author Dr. M. Kennedy Hall, a UW Medicine emergency room doctor, says, “It’s nearly painless, and you can do it while the patient is awake, and without sedation, which is critical.”

What have researchers discovered so far?

For its first clinical trial, published in the Journal of Urology, UW Medicine recruited 29 participants with ureter stones to test the feasibility of using ultrasound technology to treat stones in patients who are awake and unanesthetized. Of the 29 patients, 16 were treated with propulsion, and 13 were treated with a combination of propulsion and BWL. 

Results of the trial showed that:

• 19 patients experienced movement in their stones
• In 2 cases, the stones moved from the ureter into the bladder.
• In 7 cases, BWL fragmented the stones. 
• At a two-week follow-up, 18 of 21 patients (86%) whose ureter stones were close to the bladder passed their stones, with a four-day average passage time. 

The scientists’ next step is to conduct a clinical trial that involves both patients who would receive treatment and a control group that would not receive treatment, to further test the effectiveness of both propulsion and BWL using the new technique. Given the positive results so far, the study authors believe this technology could be used widely in outpatient clinics and emergency room settings. 

*University of Washington School of Medicine. (2022, October 7). Awake patients can have kidney stones moved, blasted: Ultrasound can be used to move, reposition or break up kidney stones, all while the patient is awake, a new study finds. ScienceDaily. Retrieved October 25, 2022, from https://www.sciencedaily.com/releases/2022/10/221007190634.htm