18.20 Rectovaginal fistulae (RVFs)

Fistulae between the rectum and the vagina (RVFs) are less common than those between the bladder and the vagina (VVFs). When a patient has a large VVF, she often has an RVF too, because both fistulae are caused in the same way—by pressure from the presenting part during a neglected obstructed labour. This causes the adjacent rectal and vaginal walls to necrose; as they heal they unite to form a fistula.

The diagnosis is obvious—faeces start to leak through a patient’s vagina 2 to 4 days after an obstructed labour, as necrotic tissue starts to separate. To distinguish an RVF from a third-degree tear, clean away her faeces, and look at her perineum. Closing an RVF can be very difficult, because it is so difficult to get at. If you have not repaired one before, make your decision to do so in her best interests. How difficult will it be to repair her, or to refer her? If you cannot refer her, you may have to try to repair her yourself. Unless someone repairs her fistula, she will have to remain with a permanent colostomy.