Nonstop leakage of urine, stool or gas is the hallmark of a fistula and needs to be evaluated. A fistula is an abnormal opening between two organs or an organ and the outside. The urine or stool flows from the high-pressure side (urinary tract or bowel) to the low-pressure side (vagina). The most common types are between the bladder and vagina (vesicovaginal), urethra and vagina (urethra-vaginal), and rectum and vagina (recto-vaginal). Less commonly you may see fistulas between the ureter (tube that carries urine from the kidneys to the bladder) and vagina (ureterovaginal) or the colon and the uterus (colo-uterine).
Urinary fistulas leak urine constantly while rectal fistulas leak intermittently with the presence of gas or stool. In developing countries, fistulas are almost always due to injury from childbirth, or ritual cutting of the vagina to enhance fertility or the labor process. In the states, urinary fistulas are usually due to surgery complications while rectal fistulas can due to delivery injuries, surgery or inflammatory bowel diseases such as Crohn’s. Sometimes women develop colo-uterine (colon to uterus) or colo-vaginal fistulas with diverticulitis. Fistula due to colon cancer must be excluded in these cases. Fistulas almost always require surgery to close.
Principles of fistula surgery are the same, no matter where the fistula occurs. The tissues must be relatively free of inflammation and the fistulous tract must be mobilized from the surrounding tissues. Closure of the high-pressure side should occur without tension and only with the minimum number of stitches required for a watertight closure. Urinary fistulas require catheter drainage to allow the fistula closure to seal. Rectal fistulas require proper bowel prep to prevent stressing the repair with constipation. After surgery, bowel rest and the use of laxatives to allow for the repair to seal are necessary for optimum outcome.