Interposition grafts for rectovaginal fistula repair in the New Zealand white rabbit

Introduction and hypothesis The objective was to use an animal model to study different types of interposition grafts for rectovaginal fistula repair. Methods Twelve New Zealand white rabbits underwent surgical creation of a rectovaginal fistula, followed by repair. Four repair techniques were studied; three with interposition grafts and one control group without a graft. Animals were euthanized at 4-week intervals and underwent gross and histologic analysis. Results The mean rectovaginal wall thickness was greatest in the control group (5.6 mm) and thinnest in the autologous rectus fascia (4.2 mm) and porcine small intestine submucosa (5.1 mm) groups. The polypropylene graft had a mean thickness of 5.4 mm and elicited a strong, protracted inflammatory response. All fistulas were successfully closed except one porcine small intestine submucosa repair. Conclusions There is no benefit from interposition graft use for rectovaginal fistula repair in our New Zealand white rabbit model.