Burst wave lithotripsy for the treatment of obstructive ureteroliths in cats

Background: Ureteroliths are a major source of morbidity and mortality in cats, and limited non-surgical options are available for their treatment. Ultrasound-guided, burst wave lithotripsy (BWL) is approved by the Food and Drug Administration to fragment renal and ureteral calculi noninvasively in awake human patients. Hypothesis/Objectives: Assess the safety and efficacy of a veterinary BWL device for the treatment of obstructive ureteroliths in cats. Animals: Eleven client-owned cats; 10 with unilateral ureteral obstruction and 1 with bilateral ureteral obstruction. Methods: In this single-arm clinical trial, BWL was performed under general anesthesia in treatments ≤90 min. Outcomes included apparent fragmentation, ureterolith passage, decrease in pyelectasia or hydroureter, and decrease in serum creatinine concentration. Adverse events were characterized by severity and relationship to BWL. Results: In total, 12 ureters with 17 ureteroliths were treated with BWL. Five ureters received 1 treatment, 6 received 2, and 1 received 3, resulting in 20 total treatments. Ureterolith fragmentation was apparent in 11 of 12 treated ureters. Of 10 ureters with follow-up imaging, 8 had ureterolith passage and an accompanying decrease in ureteral dilatation. For the cats with ureterolith passage, the median serum creatinine concentration change was −29% (range, −56% to 28%) at 1-3 weeks. One serious BWL-related adverse event of worsening obstruction from residual fragments occurred, but was solved with retreatment. Conclusions and clinical importance: Burst wave lithotripsy shows promise as a minimally invasive treatment for obstructive ureteroliths in cats. With the system used in our study, more than 1 treatment was often necessary.