Colorectal Quiz: Episode 40

About 60% of anorectal malformation patients in Chris Westgarth-Taylor's practice were discharged home without being identified as having an anorectal malformation.

Anorectal malformation occurs more commonly in females and has a prevalence of about one in 5,000 births.

When you look in laparoscopically and see an end of the colon with nothing else visible, you do not have to do a divided colostomy—you can bring out that distal end as your stoma rather than interfering with the blood supply for the distal segment.

The only potential benefit of doing a divided colostomy when encountering blind-ending colon is protecting the ultimate rectal repair, but this risks the blood supply to the distal rectum.

A single perineal orifice with no rectal or vaginal fistula must be called a cloaca.

Meyer-Rokitansky-Küster-Hauser syndrome can present with anorectal malformation, creating Meyer-Rokitansky-like anatomy where ovaries and remnant tubes are present but no midline Müllerian structures.

The more common scenario of anorectal malformation with absent vagina is a recto-vestibular fistula with completely normal urethra but no vagina in between—this is called recto-vestibular fistula with distal vaginal atresia, where the rectum ends as a fistula in the vestibule.

In this case, the rectum ended blind and quite high in the pelvis, making it unreachable through a posterior sagittal incision.

The foreshortened sacrum in this case suggests caudal regression, where everything below that level forgot to develop.

Not diverting after limited posterior sagittal anorectoplasty is safe when you have a colocolonic anastomosis at the colostomy closure site and only an anoplasty with a couple of posterior sutures.

The limited posterior sagittal incision was deliberately kept out of the perineal body to avoid destroying or scarring it for future incorporation of gynecologic structures after puberty.

In the past, vaginal replacement would have been done at the same time as rectal repair in these patients, but time and research have shown that colonic neovaginas are not great for patients 20 years down the road, and surgeons should try very hard to avoid them.

In most cloacas, you should be able to get the native vagina to reach without needing vaginal replacement.

Options for vaginal reconstruction when native vagina cannot reach include: dilating the existing introitus, opening the area and laying in a buccal graft, or waiting for tissue engineering options expected within 20 years or less.

If a neovagina bridge is functioning well without problems, there may be no reason to remove it later.

Vascular anomalies associated with anorectal malformation have not been much written about in the literature.

An aberrant external iliac artery can loop up within the abdominal wall, looking very much like the obliterated umbilical artery, while actually being a blood supply to one of the extremities.