An experimental model of urethral stricture in rabbits using holmium laser under urethroscopic direct visualization.

OBJECTIVE: To establish an experimental rabbit model of urethral stricture using holmium laser under direct urethroscopic visualization. METHODS: Sixteen adult male New Zealand rabbits were divided into equally-sized control and experimental groups. All rabbits underwent retrograde urethrography and transurethral endoscopy with a 7.5 F urethroscope after intramuscular anesthetic injection. We used a holmium:YAG laser to injure the distal urethra in all rabbits in the experimental group under direct visualization. Thirty days after surgery, all animals were evaluated with retrograde urethrography and urethroscopy. The flow rate of the isolated urethras was measured to evaluate urethral stricture formation. RESULTS: One rabbit in the experimental group (12.5%) died of infection 4 days after surgery. Thirty days after surgery, retrograde urethrography and urethroscopy revealed strictures in all seven surviving rabbits (87.5%) in the experimental group. The mean flow rate of the isolated urethras was significantly lower in the experimental group than in the control group. CONCLUSION: A rabbit model of urethral stricture can be successfully established using holmium laser under direct urethroscopic visualization, providing an ideal object for research concerning the pathogenesis and molecular biology of urethral strictures.