Acoustic Energy Fragments Painful Kidney Stones

A new study describes a next-generation lithotripsy device that uses cyclic pulses of ultrasound to fracture kidney stones at lower pressures than traditional shockwave technologies.

Developed at UC San Diego Health (UCSDH; CA, USA), Break Wave is a novel investigational device designed to apply burst wave lithotripsy (BWL) on the skin, either over the kidney or over the ureter. Once positioned, the stone is located via real-time ultrasound image guidance and a low amplitude burst of sound waves is emitted to fragment the stones, typically composed of hardened calcium oxalate, calcium phosphate, uric acid, or magnesium-ammonium-phosphate. The procedure requires little to no anesthesia.

Pre-clinical studies with a range of probes, interfaces, and outputs demonstrated the feasibility and consistent safety of BWL, which was used painlessly and without adverse events to reposition stones in 14 of 15 human study participants without restrictions on patient size, stone size, or stone location. An international, multi-center non-randomized clinical trial of the Break Wave device will recruit up to 30 patients with stones of a diameter up to 20 millimeters, with the primary goal of evaluating the device and to determine if the procedure can be done with minimal or zero anesthesia and in a non-surgical environment.

“Think of an opera singer hitting the right vocal pitch to produce vibrations that stress and break a wine glass. This is a similar concept,” said urologist Roger Sur, MD, director of the Comprehensive Kidney Stone Center at UCSDH. “The idea behind this investigational technology is to repeatedly stress certain points in the stone that cause it to fracture into small fragments, while avoiding damage to surrounding tissue.”

“If this study shows that this technology is both safe and effective in fragmenting kidney stones and does so with little to no anesthesia, it could be a game changer for patients,” concluded Dr. Sur, who performed the world’s first clinical trial procedure. “While watchful waiting is a good approach for the majority of kidney stones, we are in need of more non-invasive technologies that can treat stones without harming other structures.”

Kidney stones are often no larger than a grain of rice, yet some can grow to a diameter of several centimeters, causing blockage of the ureters. If it cannot be dissolved chemically, the kidney stone is treated using extracorporeal shock-wave therapy or minimally invasive endoscopic modalities. Many of these patients suffer from disease recurrence and need retreatment, but new stone formation might be reduced by adapting dietary habits or the use of particular medication strategies, as based on stone composition.

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