Colorectal Quiz Episode 12: Newborn ARM Part 1

Anorectal malformations (imperforate anus) occur in 1 in 5,000 live births.

Anorectal malformations occur when the anus, rectum, and nerves do not develop properly during fetal growth.

More than 90% of anorectal malformation patients have anatomy that can be ascertained on physical exam alone.

Male rectal-urethral fistulas are categorized by location on the urethra: bulbar, prostatic, or bladder neck.

95% of boys with anorectal malformations have a fistula somewhere.

The vast majority of male anorectal malformation fistulas enter into the urinary tract.

Patients with rectal-urethral fistulas need colostomies, then distal colostograms, then definitive surgery.

A flat bottom (absence of normal midline groove) is usually associated with a very high located rectum and usually associated with a bad prognosis.

With a bucket-handle malformation, you can be very confident that you have a perineal fistula right under that little bucket handle.

You can gently dilate a perineal fistula to get meconium out and spare a baby a trip to the OR if they are too ill (e.g., have a coarctation).

In black-ribbon malformations, the fistula parallels the urethra for a long distance, creating potential for urethral injury during surgery.

For black-ribbon malformations, you don't have to go crazy finding the fistula; you just need to unroof the meconium, find healthy rectum, and make an anoplasty.

In male patients with perineal fistula, the fistula is always located anterior to the center of the sphincter.

No surgical repair should be done before the first 24 hours because a patient may pass meconium through a tiny orifice and the perineal fistula should be identified.

The no-fistula defect is quite rare, only about 5% of cases.

The no-fistula defect is not surprising if you had a trisomy 21 patient.

The no-fistula defect is almost uniformly at the same level as the bulbar urethra.