UCSF

Purpose

This study reports on a prospective, multicenter, single-arm, clinical trial utilizing the SonoMotion (San Mateo, California) Break Wave lithotripsy (BWL) device to fragment urinary stones.

Materials and methods

Patients with a urinary stone underwent a single treatment of 30 minutes and peak negative pressure of 4.5 to 8 MPa. Subjects were contacted and outcomes assessed at 7, 14, and 35 days after treatment, with clinical follow-up and CT imaging 70 ± 14 days postprocedure. The primary objectives were to assess the safety (hematomas, complications, etc) and effectiveness of BWL (any fragmentation, residual fragments ≤4 mm or ≤2 mm, and completely stone-free rate) as assessed via noncontrast CT-kidneys, ureters, and bladder.

Results

Forty-four patients with a ureteral (43%) or renal (57%) stone were treated across 5 centers. Stone fragmentation occurred in 88% of cases; 70% had fragments ≤ 4 and 51% ≤ 2 mm, while 49% were completely stone free on CT; no serious adverse events were reported. Eighty-six percent of patients received either no analgesic medication at all (50%) or minor analgesia (36%). After determining optimal therapy settings, 36 patients were treated and the effectiveness improved exhibiting fragmentation in 92% (33/36), residual fragments ≤ 4 mm in 75% and 58% with fragments ≤ 2 mm with 58% completely stone free. Effectiveness was less in subjects with lower pole stones with 81% fragmentation, 71% having fragments ≤ 4 mm, 29% with fragments ≤ 2 mm, and 29% completely stone free; of distal ureteral stone patients, 89% were completely stone free.

Conclusions

BWL offered safe and effective noninvasive stone therapy requiring little to no anesthesia and was carried out successfully in nonoperative environments.

Trial registration

ClinicalTrials.gov identifier: NCT03811171.