First fragmentation of stones in humans by burst wave lithotripsy

Abstract

We report stone comminution in the first 18 human subjects by burst wave lithotripsy (BWL). Subjects undergoing clinical ureteroscopy (URS) for at least one stone ≤12 mm on computed tomography (CT) are recruited. During the planned URS, either before or after ureteroscope insertion, BWL is administered with a handheld probe for 10 min, and any stone fragmentation and tissue injury are observed. The primary effectiveness outcome is the volume percent comminution of the stone into fragments ≤2 mm, where fragment volume is determined by μCT of basketed fragments or image processing of the URS video using the laser fiber as a size reference. The primary safety outcome is independent, blinded grading of tissue injury from the URS video. Overall, 10 of 22 stones (45%) fragmented completely in 10 min. 64% and 73% were projected to fragment completely in 15 and 40 min, respectively. For reference, shock wave lithotripsy success is about 65% to fragments ≤4 mm in 40 min. Of the other six stones, one was larger than the beamwidth, two were smaller than the wavelength, and the ureteroscope introduced air bubbles around another. Only mild reddening with some hematuria was observed ureteroscopically. [Work supported by NIH-P01-DK04331.]