Ultrasound to help pass kidney stones
Official title: Ultrasound Technology to Fragment and Reposition Urinary Stones
Run by University of Washington · NCT04796792 · Data updated 2026-11-12
This test uses focused ultrasound to break and push small (2–7 mm) kidney stones to see if adults can pass them without anesthesia.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 18 Years and up |
| Sex | All |
| Enrollment | 140 (estimated) |
| Sponsor | University of Washington Academic / other |
| Locations | 3 sites (Carmel, Indiana and 2 other locations) |
| Status | Recruiting |
| Started | April 1, 2023 |
| Main results expected | May 31, 2028 |
| Study ends | October 31, 2028 |
| Registry record updated | December 9, 2025 |
| Trial ID | NCT04796792 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Adults who have at least one kidney stone measuring >2 mm and ≤7 mm on clinical imaging, can tolerate positioning for ultrasound, and are willing to follow study procedures are the best candidates, with Phase 2b specifically including people with spinal cord injury.
✕Probably not a fit
People under 18, pregnant people, those with stones larger than 7 mm, ipsilateral calcified abdominal aortic or renal artery aneurysms, uncorrected bleeding disorders, or those unable or unwilling to pause anticoagulation or be positioned for ultrasound are unlikely to benefit from this approach.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This is a prospective, open-label, multi-center protocol that combines burst wave lithotripsy (BWL) to fragment stones and ultrasonic propulsion (UP) to reposition them. It enrolls adults with kidney stones measuring greater than 2 mm and up to 7 mm and allows up to three targets per session with a maximum of 30 minutes of ultrasound exposure. The program includes a 20-subject Phase 1 feasibility cohort (completed), a planned 100-subject randomized Phase 2a arm, and a 20-subject Phase 2b cohort focused on individuals with spinal cord injury, with Phase 2b currently recruiting. Participants may return for an additional same-side session after at least 21 days once adverse events have resolved and may be treated on the contralateral side after imaging follow-up.
Why it matters
Potential benefit: If successful, the approach could allow many people to pass small kidney stones noninvasively without anesthesia, reducing the need for surgical procedures or hospital stays.
How similar studies have gone: Early feasibility reports of ultrasonic propulsion and burst wave lithotripsy have shown promising results in small cohorts, but the techniques remain experimental and are not yet widely adopted.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Individuals presenting with at least one kidney stone * Stone with maximum dimension \> 2 mm and ≤ 7 mm as determined by clinical imaging * Individuals with SCI - (Phase 2b only) Exclusion Criteria: * Individuals under 18 years of age * Individuals who are pregnant or who are trying to get pregnant * Prisoners * with cognitive impairment that would limit their ability to comprehend their role in consent or participation. * Individuals who are unable to read or understand English * Individuals who are unable or unwilling to participate in follow up activities * Individuals who cannot be positioned for ultrasound imaging * Individuals with uncorrected bleeding disorders or coagulopathies * Individuals receiving anticoagulants and who are unable or not willing to temporarily cease the medication for the investigational procedure * Individuals with a calcified abdominal aortic aneurysm or calcified renal artery aneurysm ipsilateral to the renal stone targeted by the investigational procedure * Individuals with a solitary kidney * Individuals with an uncorrected urinary tract obstruction * Individuals with an untreated infection * Individuals with a comorbidity risk which, at the discretion of the physician, would make the patient a poor candidate for the investigational procedure * Individuals who have received two previous investigational procedures for the same stone target * Individuals who have undergone the investigational procedure within the last 21 days or still have unresolved AEs from a previous investigational procedure.
Where it's running
-
VA Puget Sound Health Care System
Seattle, Washington, United States Recruiting -
University of Washington
Seattle, Washington, United States Recruiting -
Indiana University Health - North Hospital
Carmel, Indiana, United States Withdrawn
Study contacts
- Principal investigator: Jonathan Harper, MD — University of Washington
- Study coordinator: Michael Bailey, PhD
- Email: mbailey@uw.edu
- Phone: 206-619-2035
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.