In developed countries, gynecologic surgery is the most common cause of urinary tract fistulae; abdominal hysterectomy accounts for more than 50% of urinary tract fistulae associated with gynecologic surgery. Vesicovaginal fistulae are the most common type of urinary tract fistula. The incidence of vesicovaginal fistula is estimated at 1 in 1000 hysterectomies.

Bladder injury and devascularization is often the underlying etiology in the development of vesicovaginal fistulae. Suture erosion, hematoma formation, and infection may also play a role. In a rabbit model, the simple placement of a suture through the bladder and vaginal walls did not lead to fistula formation, suggesting that accompanying tissue necrosis and devascularization are necessary for the development of a urinary tract fistula. A history of pelvic irradiation, prior pelvic surgery, prior cesarean delivery, presence of pelvic infection, diabetes mellitus, chronic steroid use, and tobacco use increase the risk of fistula formation.

The most common symptom associated with urinary tract fistulae is continuous urinary incontinence and constant leakage of urine per vagina. Symptoms are often worse with positional changes, such as moving from supine to upright position. Other symptoms include vaginal discharge, hematuria, and recurrent cystitis. Postoperative fistulae usually become symptomatic 1–2 weeks after surgery but may become apparent any time in the postoperative period. Radiation-induced fistulae can take years to develop. On exam, urine is often present on the vulva and can be seen as a fluid collection in the posterior vagina. There may be evidence of skin irritation from constant contact with urine. Careful inspection with a speculum will often locate the fistula. However, it is sometimes too small to visualize on speculum exam. In these cases, a “tampon test” may help confirm a vesicovaginal or ureterovaginal fistula. To perform this test, three cotton balls are placed in the vagina, and approximately 250 mL of water or saline containing a blue dye, such as methylene blue, is instilled into the bladder via a catheter. If there is concern for an ureterovaginal fistula, the patient may be given oral pyridium or intravenous indigo carmine. The use of pyridium will allow the practitioner to distinguish between a vesicovaginal and ureterovaginal fistula by looking at the color of the cotton balls. The patient should be asked to ambulate for at least 20–30 minutes. The cotton balls are then removed and inspected for color change and wetness. Cotton balls are preferred to a tampon because they allow the physician to distinguish the level at which the staining occurs. Tampons act as a wick, drawing fluid up through the tampon regardless of the level at which the fluid exposure occurs. If the cotton ball does not change color, a fistula is less likely. Staining of the lowermost cotton ball may suggest other forms of incontinence. A cystogram may also be helpful in the diagnosis of a vesicovaginal fistula.

Cystourethroscopy is essential to determine the exact anatomic location of the fistula in the bladder and its relation to the ureteral orifices. The condition of surrounding tissues can also be evaluated with cystoscopy. Intravenous pyelogram or retrograde pyelography is recommended for all cases of vesicovaginal fistula as well as all suspected cases of ureterovaginal fistula to evaluate ureteral involvement.

When the diagnosis of vesicovaginal fistula is confirmed, bladder drainage should be accomplished. If the fistula is less than 2 cm, continuous bladder drainage with an indwelling catheter alone may allow for spontaneous closure of the fistula. Prompt diagnosis and institution of bladder drainage increases the chances of spontaneous healing. In one study, 15–20% of fistulae closed spontaneously with up to 6 weeks of bladder drainage. To maximize the chances for a successful surgical repair, a waiting period of at least 3 months is usually indicated to allow maturation of the fistulous tract and minimize the associated inflammation. This waiting period is somewhat controversial; the basic principle is that the repair should be timed such that surrounding inflammation and edema are minimized. It is generally recommended that continuous bladder drainage be maintained until the time of surgical repair. Antibiotic prophylaxis is controversial in this setting. In general, it is not recommended that patients receive continuous antibiotic prophylaxis with prolonged catheterization as it only leads to the development of antibiotic resistance and does not reduce the incidence of symptomatic infections. Bacterial colonization of the catheter is nearly universal after 30 days; therefore, only symptomatic infections should be treated. However, a course of antibiotics is indicated perioperatively to sterilize the urine when surgical intervention is planned.