Colorectal Quiz 25: Perineal Groove

In the UK, surgeons are addressed as 'Mr.' rather than 'Dr.' because barbers were the forerunners of surgeons, while doctors were a separate profession.

Visual inspection ('eyeballing') is reliable for assessing anal position and presence of perineal body; measurements can be difficult in wriggling babies and it's hard to define the center and measurement points reliably.

The anus needs to be supple without narrowing or stenosis; even if an adequately sized Hagar passes through a stenotic ringed anus, that anus might not function well.

Checking anal size with Hagar dilators alone can give a false sense that size is adequate; distensibility is more important than just passing a dilator through.

If uncertain whether the anus is properly centered in the sphincter by visual inspection, examination under anesthesia with electrical stimulation can confirm that the sphincter maps correctly and closes around the anal opening.

Perineal groove is not a common diagnosis, but there is a sense that it is being seen more often than in the past.

Perineal groove has been misdiagnosed as perianal fissure, perineal trauma, non-accidental injury (NAI), dermatitis, or infection; if you haven't seen it before, it's hard to spot.

Perineal groove is seen less than half a dozen times per year, probably countable on one hand.

An 'anterior anus' is a normal anus that happens to be anterior and does not need fixing; Arthur Alsis said it's very hard to improve on an asymptomatic patient.

A perineal fistula (as distinct from an anterior anus) is fistulous tissue that is too small, not distensible, lacks a dentate line, and is anterior to the center of the sphincter.

When repairing a perineal fistula that coexists with a perineal groove, the mucosal trough is excised at the same time.

Most perineal grooves will epithelialize over time and become squamous epithelium of no consequence.

Excision of perineal groove is considered only in rare cases with problematic weeping of mucus; this has been done perhaps once in clinical practice.

Perineal groove is probably the most minor part of the anorectal malformation spectrum, based on observation of 2-3 cases in association with either perineal fistula or rectovaginal fistula, occurring more than random chance would suggest.

A VACTERL workup is recommended for any patient with an anorectal malformation, including perineal groove, because the tests are non-invasive and stratifying workup by severity leads to system errors and confusion.

Spinal ultrasound should be performed within a reasonable time period (institution-dependent) because if not done early and a question about tethered cord arises later, it cannot be answered.

If a patient has no anus, it's a cloaca with a single perineal opening; if a patient has a patent normal anus and a urogenital sinus, that suggests an endocrine problem.

With proper labial retraction in this case, a urethra and vagina could be easily seen, ruling out an endocrine problem and confirming appropriate gender assignment.

Perineal fistulas with tethered cord have been observed, and incomplete VACTERL workup has resulted in missed diagnoses such as solitary kidney discovered only at age 6.