Failure of holmium:yttrium-aluminum-garnet laser lithotripsy in two horses with calculi in the urinary bladder

Laser lithotripsy appears to be a viable alternative to standard techniques for the treatment of urolithiasis in horses. Holmium:yttrium-aluminum-garnet lasers fragment uroliths primarily through a photothermal mechanism, which is distinct from the photoacoustic fragmentation process associated with pulsed dye lasers. Lithotripsy with a holmium:yttrium-aluminum-garnet laser may require longer surgical times than lithotripsy with a pulsed dye laser and may be ineffective in horses with certain types of urinary calculi.