Anorectal malformations, specifically imperforate anus, are said to occur in approximately 1 in 5000 births.

Synonyms or related terms include anal atresia, anal membrane, anal stenosis, anorectal malformations, ectopic anus, high imperforate anus, low imperforate anus, perineal anus, rectoperineal ristula.

With an imperforate anus, a normal anal opening is absent and the anus and rectum are not developed properly. This condition has been found to more slightly affect boys than girls. Some resources indicate that it happens during the fifth to seventh week of pregnancy; some sources say between the seventh and tenth week of gestation.

From my research, imperforate anus may present in different ways, from the total absence of an anal opening, a very small opening in the wrong position, a fistula connecting to part of the urinary tract or the reproductive system, a single opening called a cloaca in girls where the rectum, urethra, and vagina are joined…

The malformations are classified as low malformations or high malformations. High anomolies are more common in male; low lesions in females.

Typically, one of two treatment avenues will be taken. Surgery to perform a perineal anoplasty is indicated in some cases of low imperforate anus.

In most cases, a colostomy is performed. (A colostomy is where a stoma (opening) from the colon to the surface of the body is created to function as an anus. The bowel movements / intestinal contents are contained in a bag / pouch.) The decision for colostomy is usually made after 24 hours of observation.

The child is then permitted to grow and develop for some months before what is known as a “pull through” procedure (otherwise known as Posterior Sagittal AnoRectoPlasty or PSARP) is performed. The PSARP procedure is also known as the “Peña procedure” which is named after Alberto Peña, MD the creator of the posterior sagittal anorectoplasty surgery method.

The pull-through procedure involves “pulling down” the rectum and sewing it into an anal opening which has been created in the perineum. Therapy begins two weeks after surgery and involves anal dilatations being administered by the parent or hospital.

Once the anus is ready, a colostomy closure follows.