Laser lithotripsy for removal of uroliths in dogs

Abstract

Introduction: This study evaluated the ability to fragment and remove naturally occurring uroliths in dogs using a holmium: YAG laser. Methods: Twenty four dogs with naturally occurring uroliths including 10 spayed females and 14 neutered males. The dogs were 8.7 ± 2.8 years old and weighed 13.7 ± 8.0 kg. All dogs had bladder stones and 5 male dogs also had urethral stones. In female dogs, cystoscopy was performed using a rigid cystoscope with sheath diameter of 14 to 19 french. Cystoscopy was performed in males dogs using a 7.5 french diameter pediatric ureteroscope. Uroliths were fragmented using a 20 watt Holmium: YAG laser and the fragments were removed by basket extraction and voiding urohydropropulsion. Results: Average laser parameters for urolith fragmentation were 0.7 Joules at 8 Hertz (range: 0.5 to 1.3 Joules at 5 to 13 Hertz). All urolith fragments were successfully removed in all 10 female dogs and 11 of 14 male dogs. In one male dog, the urethra was too small to allow passage of the ureteroscope. In one of the male dogs, the urethral stones were successfully removed by laser lithotripsy, but removal of the bladder stones was performed by cystotomy. There was one complication of urethral perforation during attempts to pass an access sheath transurethrally in a dog with extensive proliferative urethritis. Conclusions: Laser lithotripsy is a safe and effective method of removing bladder and urethral stones in dogs provided the dog is large enough to permit transurethral passage of a cystoscope or ureteroscope.