Endoscopic-assisted disruption of urinary calculi using a holmium:YAG laser in standing horses.

Objective: To describe a technique for endoscope-assisted disruption and removal of urinary calculi using a holmium:YAG laser in sedated, standing horses.

Study Design: Retrospective study.

Animals: Six horses with urinary calculi.

Methods: A holmium:YAG laser was used to disrupt naturally occurring urinary calculi in horses (4 geldings, 1 stallion, 1 mare). Ischial urethrotomy was performed in male horses to provide a portal for the endoscope and laser fiber. Calculus fragments were removed by a combination of lavage, transendoscopic basket snare removal, forceps, and digital manipulation. Ischial urethrotomies healed by second intention. Follow-up was obtained by recheck examination and telephone interview of owners.

Results: No major operative or postoperative complications occurred. Two calculi (1 stallion and 1 mare) were fragmented by a combination of laser ablation and manual disruption with a lithotrite. Postoperative dysuria occurred in the mare, but resolved after 1 month. Mean (+/- SD) follow-up was 306 +/- 149 days; no other complications were reported.

Conclusions: Calcium carbonate urinary calculi (up to 15 cm in diameter) in horses can be effectively fragmented with a holmium:YAG laser. It is not known if this technique would be completely effective for larger calculi or extremely dense calculi.

Clinical Relevance: Calculus disruption by an endoscopically assisted holmium:YAG laser offers a minimally invasive method that can be performed in standing horses and that minimizes patient risk.