An experimental model of bulbar urethral stricture in rabbits using endoscopic radiofrequency coagulation

To develop an experimental model of endoscopic urethral stricture mimicking the human clinical situation.

Twenty-four New Zealand male rabbits were included. Eighteen animals (study group) underwent videourethroscopy with a pediatric resectoscope, and a 3 to 5-mm-long circumferential electrocoagulation of the bulbar urethra was performed, without postoperative urinary diversion. Six animals underwent the same procedure without application of electrocautery (control group). Each animal was assessed for urethral stricture on day 15 and day 30 by videourethroscopy and voiding cystogram. Among the study group, 8 animals were killed on day 15 and 10 on day 30 for histologic evaluation. All the control animals were killed on day 30 for histologic examination.

Nine animals (50%) in the study group developed a significant bulbar stricture (reducing the lumen by more than 50%) at day 15. Histologic examination confirmed the presence of hyalin fibrosis mutilating the urethral wall. No spontaneous improvement of the stricture was observed on day 30. None of the controls developed urethral stricture, and histologic examination showed a normal urethra in each case.

Endoscopic electrocoagulation of the urethral wall provides a reproducible model of stricture in the rabbit.