Functional and Morphological Changes Associated with Burst Wave Lithotripsy-Treated Pig Kidneys

Burst wave lithotripsy (BWL) is a new technique for comminution of urinary stones. This technology is noninvasive, has a low positive pressure magnitude, and is thought to produce minor amounts of renal injury. However, little is known about the functional changes related to BWL treatment. In this study, we sought to determine if clinical BWL exposure produces a functional or morphological change in the kidney. Twelve female pigs were prepared for renal clearance assessment and served as either sham time controls (6) or were treated with BWL (6). In the treated group, 1 kidney in each pig was exposed to 18,000 pulses at 10 pulses/s with 20 cycles/pulse. Pressure levels related to each pulse were 12 and -7 MPa. Inulin (glomerular filtration rate, GFR) and para-aminohippuric acid (effective renal plasma flow, eRPF) clearance was measured before and 1 hour after treatment. Lesion size analysis was performed to assess the volume of hemorrhagic tissue injury created by each treatment (% FRV). No visible gross hematuria was observed in any of the collected urine samples of the treated kidneys. BWL exposure also did not lead to a change in GFR or eRPF after treatment, nor did it cause a measurable amount of hemorrhage in the tissue. Using the clinical treatment parameters employed in this study, BWL did not cause an acute change in renal function or a hemorrhagic lesion.