Cystoscopy-assisted urolith retrieval via a perineal urethrostomy stoma in male cats.

ObjectivesWe sought to characterize cystoscopy-assisted urolith retrieval via a perineal urethrostomy stoma (CUPU) initially in a cadaveric model and then in clinical cases. We hypothesized that a CUPU would provide a reasonable alternative to the traditional approach of performing a cystotomy after perineal urethrostomy in male cats with complex or recurrent urolithiasis-associated urethral obstruction (UO).MethodsA perineal urethrostomy (PU) was performed in 20 male cat cadavers. A randomly assigned number of synthetic calculi (SynC) was placed retrograde into the urinary bladder, and an endoscopist blinded to the SynC number, performed CUPU using a flexible ureteroscope and basket retrieval device. Procedure characteristics were summarized with descriptive statistics. After completion of the cadaver phase, two male cats with naturally occurring complex or recurrent urolithiasis-associated UO that warranted PU were recruited to undergo CUPU. Clinical features and outcomes of these cases were described.ResultsFour cadavers were excluded because of urethral tearing during SynC placement. A narrow urethral lumen precluded ureteroscope passage in two cadavers. In the 14 remaining cadavers, a median of 7.5 SynC (range 3-9) were placed in the urinary bladder. The CUPU median procedural time was 13.2 mins (range 6.1-24.0) and all 99 (100%) SynC were successfully retrieved from the 14 cadavers. Scope-associated tearing of the urethra or surgical site was not observed in any cadavers. Two client-owned cats with struvite urolithiasis-associated UO underwent a PU followed by CUPU. All uroliths were successfully retrieved, and periprocedural complications were not observed. Both cats had normal stoma sites 4 weeks postoperatively and neither cat had owner-reported dysuria 3 months postoperatively.Conclusions and relevanceThis study highlighted that CUPU is a feasible procedure with the potential to obviate the need for abdominal surgery in some cats with cystolithiasis and urolithiasis-associated UO that warrant PU.