SonoMotion has received de novo clearance from the FDA for its Stone Clear device, a non-invasive solution designed to aid in the passage of residual kidney stone fragments following lithotripsy. This clearance marks a significant advancement in the management of kidney stones, offering a new option for patients seeking to avoid complications and repeat procedures.
The Stone Clear device utilizes non-invasive ultrasound pulses to facilitate the clearance of residual kidney stone fragments in a clinic setting, eliminating the need for anesthesia. According to James E. Lingeman, MD, Clinical Professor of Urology at Indiana University School of Medicine, "Patients with post-lithotripsy residual fragments are more likely to have complications, emergency department visits, or repeat procedures, yet they have no reliable non-invasive option aside from passive observation. The Stone Clear device provides patients with a non-invasive option to reduce their residual fragment stone burden in the clinic environment while being fully awake."
Clinical Evidence Supporting Stone Clear
The safety and effectiveness of ultrasonic propulsion were demonstrated in a prospective, open-label, randomized, controlled study (NCT02028559). The results, published in The Journal of Urology, indicated that ultrasonic propulsion reduced relapse—defined as stone growth, a stone-related urgent medical visit, or surgery—and added minimal risk in facilitating kidney stone fragment clearance compared with observation.
At a 5-year follow-up, the time to relapse was significantly longer in the ultrasonic propulsion arm compared to the control arm (P < .003). Specifically, the restricted mean time-to-relapse was 1530 days (± 92 days) for patients receiving ultrasonic propulsion, compared to 1009 days (± 118 days) in the observation arm. This translates to a 52% longer restricted average time to relapse with the intervention.
Overall, 8 of 40 patients in the ultrasonic propulsion arm and 21 of 42 patients in the observation arm experienced relapse (HR, 0.30; 95% CI, 0.13-0.68), indicating a 70% lower risk of relapse in the treatment arm. Furthermore, 63% of patients (n = 24) in the treatment arm visually passed kidney stone fragments within 3 weeks of treatment, compared to only 5% of patients (n = 2) in the control arm.
Safety Profile
Regarding safety, 63% of patients (n = 25) in the ultrasonic propulsion cohort and 40% of patients (n = 17) in the observation cohort experienced an adverse event (AE) (OR, 2.45; 95% CI, 1.01-5.96). However, all AEs were reported as mild, transient, and self-resolving.
The study included 82 patients, with 40 receiving ultrasonic propulsion and 42 undergoing observation. Eligible patients had at least one suspected stone remaining following lithotripsy, with individual stone fragments of 5 mm or smaller in largest dimension, and were at least 4 weeks post-lithotripsy. The median follow-up was 3.0 years (IQR, 1.8-3.2), with relapse defined as stone growth, a stone-related urgent medical visit, or surgery by 5 years or study end.
The study authors suggest that ultrasonic propulsion may be a valuable option for removing small stones or residual fragments, especially when combined with other ultrasound-based technologies like burst wave lithotripsy.
SonoMotion's Break Wave, another solution for kidney stone management, is currently undergoing clinical trials in the United States and Canada.
