A Complex Urogenital Malformation: Urogenital Sinus with Normal Anus

Why This Exists

Urogenital sinus anomalies represent a spectrum of congenital malformations where the vagina and urinary tract share a common channel instead of opening separately at the perineum 0:05. When the anus develops normally—as it does in roughly half of these cases—the surgical problem becomes purely urogenital: how to separate the vagina from the urinary tract while preserving continence and sexual function 0:05. The approach depends entirely on the anatomy of that shared channel 0:47.

The Core Problem

The urogenital sinus exists in two main configurations. The most common variant has a long urethra and a short common channel 0:05. For these cases, the entire urogenital complex can be mobilized as a unit and brought to the perineum—a procedure called total urogenital mobilization 0:13.

The less common variant—and the subject of this case—inverts that anatomy: a long common channel with a short native urethra 1:37. Here, mobilizing the entire complex would leave the patient with an inadequately short urethra 1:43. The solution is urogenital separation: detach the vagina from the common channel and allow the common channel itself, combined with the short native urethra, to become the neourethra 1:43. The vagina is then brought to the perineum separately 4:12.

Cystoscopy determines which anatomy you are facing and therefore which operation to perform 1:37. This is not a judgment call—it is a measurement that dictates the approach 0:47.

How the Approach Works

Urogenital separation for a patient with a normal anus requires exposure that does not exist through standard perineal incisions 0:32. The trans-anorectal approach solves this by temporarily dividing the anal canal and perineal body in the midline, then extending posteriorly with a posterior sagittal incision 0:32. This is an extension of the ASTRA concept, which involves incising only the anterior wall of the anus for exposure 2:30.

The patient is positioned prone 2:03. The anal canal is marked with silk sutures before it is divided—these marks will guide its reconstruction at the end of the case 2:12. The perineal body and anal canal are then opened in the midline, and the incision is extended posteriorly to create a posterior sagittal exposure 0:32.

Once the vagina is visualized, it is opened in the midline 3:21. This reveals the fistula between the vagina and the common channel 3:21. Silk sutures placed on the anterior vaginal wall provide traction and facilitate mobilization of the vagina off the urinary tract anterior to it 3:36. The goal is to separate the vagina completely while leaving the common channel intact 1:43.

The fistula—now the posterior wall of what will become the neourethra—is repaired in two layers 4:03. An ischiorectal fat pad is mobilized and placed over the repair to provide an additional tissue barrier 4:08. This interposition reduces the risk of recurrent fistula formation 4:08.

The vagina is then mobilized until it reaches the introitus without tension 4:12. It is sutured first to the posterior urethral meatus, then the introitoplasty is completed 4:17. The perineal body is repaired, the anal canal is reconstructed using the previously placed silk sutures as guides, and the anterior rectal wall is closed 2:12.

Where Practice Is Contested

The choice between total urogenital mobilization and urogenital separation is not contested—it is determined by anatomy 0:47. What varies among surgeons is the threshold for using the trans-anorectal approach versus a purely perineal or anterior approach 0:32. Some surgeons reserve the trans-anorectal approach for cases where exposure through the perineum alone is inadequate; others use it routinely for high urogenital sinus repairs to maximize visualization 0:32.

The use of tissue interposition—in this case, an ischiorectal fat pad—is standard practice, but the specific tissue used varies by surgeon preference and local anatomy 4:08.

When to Involve This Team

Urogenital sinus anomalies are typically identified in infancy, either at birth or during evaluation for ambiguous genitalia 0:05. Definitive repair is usually deferred until the child is older to allow for growth and to facilitate reconstruction 0:05.

Referral to a pediatric surgeon or pediatric urologist with experience in complex urogenital reconstruction should occur as soon as the diagnosis is made 0:47. Early consultation allows for coordinated evaluation, including cystoscopy and genitography to define the anatomy, and for family counseling about the planned approach 0:47 1:37.

For referring clinicians, the key is recognizing that a single perineal opening in a female infant is not simply an imperforate hymen or labial adhesion—it is a urogenital sinus until proven otherwise 0:05. Any infant with a single perineal opening requires imaging and specialist referral before any intervention is attempted 0:47.