Background: The height of the urogenital sinus confluence dictates the type of repair required and is determined by the lengths of the common channel and urethra. Usually the urethra is long (>1.5 cm) and the common channel (CC) is short (<3 cm), and a total urogenital mobilization (TUM) can be performed using a perineal approach. However, in patients with a complex urogenital sinus (short urethra [<1.5 cm] and long CC [>3 cm]), a urogenital separation (UGS) is preferred to preserve urethral length and prevent urinary incontinence. It can be difficult to reach the urogenital complex in patients with a high confluence from a posterior or perineal approach, and thus the anterior wall of the rectum may need to be incised using an anterior sagittal transanorectal (ASTRA) technique if the exposure is inadequate. In rare cases, a transanorectal approach - incising both the anterior and posterior rectal walls - may be necessary.
Methods: We demonstrate our approach to such a case and note the key surgical steps to a urogenital sinus repair in a patient with a complex urogenital sinus and normal anus, in which the common channel was long and the urethra short. The anorectum was split in the midline in both the anterior and posterior walls to gain access to the confluence of the urogenital sinus.
Results: Initial cystoscopy of the patient revealed a long CC (> 3 cm) and a short urethra (<1.5 cm). In this situation, a UGS was planned whereby the vagina is separated from the common channel and pulled through separately to the perineum, and the common channel plus the urethra become the neourethra. The procedure began by incising the perineal body and anus in the midline. An ASTRA approach did not provide adequate exposure and the posterior anorectum was thus additionally incised. This allowed excellent exposure to the urogenital sinus complex, leading to identification of the vagina inserting into the CC. The posterior vagina was opened in the midline and the fistula to the urethra identified. The anterior wall of the vagina was then mobilized off of the urinary tract and the defect in the posterior CC repaired in layers in a watertight fashion and covered with an ischiorectal fat pad. The CC was then in continuity with the urethra, creating a neourethra. The vagina was pulled through and anastomosed to the introitus. The perineal body was repaired and the anal canal and rectum reconstructed. No fecal diversion was utilized.
Conclusions: In patients with a complex urogenital sinus, a transanorectal approach, in which both the anterior and posterior walls of the rectum are incised, is an excellent way to gain additional exposure to the urogenital sinus.