**7.1 Type I atresia ani**

Animals with this type of atresia ani are placed in ventral decumbency and treated with resection of the strictured portion of the rectum through a 3600 anoplasty. After excision of the stricture the rectal mucosa is brought distally so as mucosa to skin apposition is achieved with simple interrupted sutures using synthetic non absorbable monofilament 4/0- 5/0 suture material (Figure 19). Care is taken during dissection to preserve the external anal

Fig. 19. Anoplasty in the dog of figure 8 with atresia ani type I.

Atresia Ani in Dogs and Cats 191

Fig. 21. The rectum of the dog of figure 9 was mobilized and opened to allow an anoplasty

Fig. 22. The rectal mucosa of the dog of figure 9 was sutured to the skin with simple

symphisiotomy procedure (Hosgood & Hoskins, 1998; Aronson, 2003).

Animals with this type of atresia may need an abdominal approach to isolate, mobilize and anastomose the cranial colon with the distal colon and rectum usually through a pubic

interrupted nylon sutures to complete the anoplasty.

**7.3 Type IV atresia ani** 

procedure.

sphincter and anal sacs (Hosgood & Hoskins, 1998; Aronson, 2003; Prassinos et al., 2003; Ellison & Papazoglou, 2011). Type I atresia ani may also be treated with bougienage or balloon dilatation in a single or multiple treatments; however, failures are not uncommon (Hosgood & Hoskins, 1998; Webb et al., 2007; Tomsa et al., 2011; Ellison & Papazoglou, 2011). Recently, a single balloon dilatation procedure alone or combined with intralesional triamcinolone injection was used to successfully treat type I atresia ani in 5 kittens and two dogs (Webb et al., 2007; Tomsa et al., 2011). Prospective studies are needed to evaluate balloon dilatation for the treatment of congenital anorectal strictures in small animals.
