Strictures are a narrowing of the lumen due to cicatricial tissue. Injury may result from foreign bodies or trauma (eg, bite wounds, accidents), as a complication of inflammatory disease (eg, perianal fistula disease, histoplasmosis, inflammatory bowel disease, anal sacculitis), or due to neoplasia (eg, scirrhous adenocarcinoma).
Neoplasia, enlarged prostate, and scar tissue after perianal fistula or anal sac abscess may all predispose to extraluminal constriction. In small animals, anorectal stricture is more common than rectal strictures, but neither is frequent. Strictures are more common in German Shepherds, Beagles, and Poodles.
Rectal stricture in cattle may result from trauma, neoplasia, or fat necrosis impinging on or within the lumen, or from defects associated with rectal and vaginal strictures. Rectal strictures in pigs are seen secondary to enterocolitis, after repair of rectal prolapse, and as a sequela of ulcerative proctitis induced by salmonellae.
Treatment in small animals for benign strictures includes general anesthesia followed by digital bougienage or balloon dilation of the stricture, which may need to be repeated. Intralesional injections of long-acting corticosteroids (triamcinolone) are used, but the benefit of this therapy is unclear. Rectal stenting may be used for recurrent or malignant strictures if surgical resection is not an option. Treatment in large animals may include resection of the strictured area or rectal pull-through.
