This study examines the use of ultrasonic propulsion for removing small residual kidney stone fragments, a non-invasive, non-surgical technique aimed at promoting stone clearance and preventing relapse. The researchers previously demonstrated that removing small, asymptomatic renal stones during surgery for other ureteral or contralateral stones significantly reduced the risk of relapse. In this trial, 82 adults with kidney stone fragments smaller than 5 mm were randomized into two groups: one group received ultrasonic propulsion to reposition fragments for easier passage, while the other group underwent observation without intervention. The primary outcome measured was relapse, which was defined as symptomatic medical visits, surgeries, or stone growth assessed via annual CT scans.
After an average follow-up period of 2.6 years, the treatment group showed a 70% reduction in relapse risk compared to the control group (hazard ratio 0.30), with relapse occurring in only 20% of treated patients versus 50% in the control group. Furthermore, the treatment group experienced 52% longer time-to-relapse, and the passage of fragments within the first three weeks was significantly higher (63% vs. 5% in the control group). The adverse events reported were mild and transient, with 63% of patients in the treatment group and 40% in the control group experiencing some form of side effect. These findings suggest that ultrasonic propulsion is an effective, low-risk method to help remove small stone fragments, reduce relapse, and improve long-term outcomes for patients with kidney stones.
