Procedure

Obtain preliminary film of lower abdomen and pelvis to identify any residual contrast media and abnormal gas collections and to accurately locate any pelvic calcifications.

With the patient lying in the left lateral position, insert a Foley catheter (Bard Urological Co., Covington, GA) with a 30-ml balloon into the introitus of the vagina. While the catheter is held in place, the balloon is gently inflated just inside the introitus until a snug fit is achieved. Occasionally, a larger balloon may be required to prevent leakage; in which case, a barium enema tip with balloon cuff (90-100 ml) may be used.

Hypaque 60 or Renografin 60 is gently injected into the catheter from a syringe. Between 25 and 50 ml is usually sufficient to demonstrate most fistulas, unless there is a particularly large associated abscess cavity. 

Note: If the patient has not undergone a hysterectomy, there may be filling of the cervical canal, uterine cavity and fallopian tubes during a normal examination. The use of barium as a contrast agent is contraindicated because of the risk of venous intravasation and peritoneal spillage.