Burst wave lithotripsy - a paradigm shift: inferences from a scoping review

Abstract

Purpose: Urolithiasis, a condition affecting approximately 10% of the global population, is primarily treated with Shock Wave Lithotripsy (SWL) and endoscopic methods. However, SWL's high-pressure pulses can cause tissue injury, often necessitates some level of anaesthesia, and may require repeated sessions or ancillary treatment to achieve stone free status. Burst Wave Lithotripsy (BWL) emerges as a promising alternative, utilizing multi-cycle, ultrasound bursts at lower pressure amplitude to fragment stones, while minimizing cavitation under real-time imaging in a portable manner.

Methods: This scoping review evaluated BWL's efficacy, safety, and clinical potential. A systematic search identified 19 eligible studies, including in vitro experiments, preclinical trials, and human clinical trials.

Results: In vitro studies demonstrated BWL's capability to fragment urinary stones of diverse compositions with high comminution rates. Higher ultrasound frequencies produced smaller fragments (< 1 mm), while lower frequencies resulted in larger fragments (3-4 mm), allowing for controlled fragmentation tailored to clinical needs. Preclinical trials in porcine models showed lower pressure and reduced cavitation, which account for BWL's safety, causing less associated tissue injury even in anticoagulated subjects. Human trials reported BWL as well tolerated in awake patients with high fragmentation success rates (88-91%) and low complication rates. BWL offers distinct advantages, including lower cavitation and tissue injury risks, portability, and anaesthesia-free application. Ongoing trials aim to validate BWL's efficacy and explore its combined use with ultrasonic propulsion.

Conclusion: BWL represents a paradigm shift in lithotripsy, offering controlled fragmentation, reduced tissue injury, fragment propulsion and portability for office-based or ambulatory care. Early clinical evidence underscores its safety and efficacy, even in anticoagulated patients. While large-scale trials are needed to solidify its role, BWL's procedural flexibility positions it as a transformative alternative to SWL, poised to redefine urolithiasis management.

Keywords: Break wave; Burst wave; Lithotripsy; Nephrocalcinosis; Shock wave; Ultrasound propulsion.

Fig. 1

(a) Burst Wave Lithotripsy machine; (b) Burst Wave Lithotripsy probe