Imperforate Anus: Intermediate and High Type

Abstract

Newborns with intermediate- or high-type imperforate anus mostly have no anal opening. Invertography can suggest the level of the rectal end and a stoma is constructed. It is necessary to determine the correct subtype by contrast studies of the colon and the urinary tract before anorectoplasty. Full understanding of the muscle anatomy is necessary for desirable anorectoplasty, and the procedure includes approach to the rectum, transection of the fistula, rectal mobilization, construction of the pull-through route, and anoplasty.

The rectum can be mobilized by sacral approach after minimal incision of the posterior muscle and the fistula is transected. If the rectum ends up high, abdominal or laparoscopic approach is necessary to transect the fistula. Tunnel is made from the anterior aspect of the puborectalis muscle to the anal pit with angulation while confirming muscle contraction by electrical stimulation. By posterior-sagittal anorectoplasty, long vertical sacroperineal incision is made, and the muscle complex is divided sharply in the midline to reach the rectum. The mobilized rectum is pulled through or placed at the center of the muscle complex while making an anterior angulation. The rectum is anchored to the external sphincter muscle, and its end is sutured to the skin flap.

Postoperative management includes dilatation immediately after anorectoplasty and daily enemas for a long period. Enemas can be reduced after achieving fecal continence. Laxatives are prescribed if necessary to prevent constipation. For children with high type, care should be focused to prevent an accident in public and be multidisciplinary and sometimes would be necessary beyond the adult life.

The figures in this chapter are reprinted with permission from Standard Pediatric Operative Surgery (in Japanese), Medical View Co., Ltd., 2013, with the exception of occasional newly added figures that may appear.