Vesicovaginal and Ureterovaginal Fistula

Updated: Dec 18, 2018
  • Author: Sandip P Vasavada, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Overview

Practice Essentials

A fistula is defined as a communication between 2 organ sites. Vesicovaginal fistula is a free communication between the urinary bladder and the vagina. The urine from the bladder freely flows into the vaginal vault, leading to total or continuous incontinence. Ureterovaginal fistula is a communication between the distal ureter and the vagina. The urine from the ureter bypasses the bladder and flows into the vagina. This also results in total or continuous incontinence. Urinary incontinence resulting from these fistulas may mimic symptoms of stress urinary incontinence. 

Obstetric trauma resulting in fistula formation is most common cause of urinary fistulas in developing countries. In developed countries, more than 50% of such fistulas occur after hysterectomy for benign diseases such as uterine fibroids, menstrual dysfunction, and uterine prolapse. [1, 2]  

The acute onset of urinary incontinence occurring shortly after a difficult hysterectomy should raise suspicions for vesicovaginal or ureterovaginal fistulas. If vesicovaginal or ureterovaginal fistula is suspected, as an immediate therapy, insertion of a urethral catheter to minimize urine leakage and the patient's distress can be considered. Spontaneous closure can occur in up to 15% of cases using catheter drainage Conservative approaches are more likely to be successful for nonradiotherapy fistulae. [3]

The commonly chosen surgical approaches for the correction of vesicovaginal fistula include the transabdominal and transvaginal approaches. Historically, the site of the fistula often dictated the surgical approach. Supratrigonal fistulas (fistulas above the interureteric ridge) were typically approached transabdominally. Infratrigonal fistulas (fistulas below the interureteric ridge) were corrected transvaginally. Most surgeons prefer the transabdominal approach for both supratrigonal and infratrigonal fistulas because access to the fistula is easier. Supratrigonal fistulas are more difficult to reach transvaginally.

Currently, the transvaginal approach is preferred because it results in less morbidity. The transvaginal approach is the safest and most comfortable for the patient. Additionally, it has been reported that closure is significantly more likely to be achieved using a transvaginal approach than a transabdominal technique (90.8% success vs 83.9%). [3] However, if the fistula site is difficult to access transvaginally, the transabdominal route remains a safe and effective alternative.

For excellent patient education resources, see eMedicineHealth's patient education articles Intravenous PyelogramCystoscopy, and Foley Catheter.

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Pathophysiology

Unrecognized bladder injury during a difficult hysterectomy or cesarean delivery may result in vesicovaginal fistula formation. Most vesicovaginal fistulas are caused by dissection of the bladder during the mobilization of the bladder flap, which causes devascularization or an unrecognized tear of the posterior bladder wall. Alternatively, if the vaginal cuff suture was unknowingly incorporated into the bladder, this can result in tissue ischemia, necrosis, and subsequent fistula formation.

The ureter may become injured during the dissection around the infundibulopelvic ligament or ligation of the uterine vessels. Unexpected pelvic hemorrhage may obscure the surgeon's vision and result in ureteral injury that manifests as delayed ureterovaginal fistula.

Fistulas resulting from vaginal birthing occur during difficult or prolonged labor. The head of the fetus compresses the trigone or the bladder neck against the anterior arch of the pubic symphysis. This may result in tissue ischemia, necrosis, and eventual fistula formation. Today, this is rare in the United States.

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Etiology

In the United States, more than 50% of vesicovaginal and ureterovaginal fistulas occur after hysterectomy for benign diseases such as uterine fibroids, menstrual dysfunction, or uterine prolapse.

Pelvic radiation is the primary cause of delayed fistula, which can occur from one month to many years after the initial radiation treatment. Radiation treatment is typically used to treat cervical or endometrial carcinoma. Vesicovaginal fistula may occur with or without cancer recurrence.

In developing countries, obstetrical complications are the most common cause of vesicovaginal and ureterovaginal fistulas. This may develop in cases of long-standing and obstructed labor leading to pressure necrosis on the anterior vaginal wall. Fistulas in this setting may be large and have extensive local tissue damage and necrosis.

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Epidemiology

A systematic review over a 35-year period reported 83.2% of fistula in developed countries were iatrogenic whereas 95.2% of fistula in developing countries were the result of obstetric complications. [3]  However, the incidence of vesicovaginal fistula resulting from hysterectomy is estimated to be less than 1%. Approximately 10% of such fistulas may involve one or both ureters. Some fistulas may be more complex, involving adjacent organs. If the rectum is involved in the inflammatory reaction, rectovaginal fistula may develop. [4]

The estimates of the global prevalence of untreated obstetric fistula vary from 654,000 to 3,500,000. In Ethiopia, Malawi, and Bangladesh, reported incidence ranges between 1.5 and 1.7 per 1000 women. An estimated 33,451 new cases occur annually in rural sub-Saharan Africa. Hospital-based reports show the incidence to be between 0.6 and 6.5 per 1,000 births. [5]

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Prognosis

The success rate of vesicovaginal and ureterovaginal fistula repair approaches 90% at first attempt and approaches 100% after a second attempt. However, realize that the second operation is more extensive and more complex than the first operation. Often, the surgical approach must be changed, and additional procedures, such as Martius flap, peritoneal flap, omental flap, or gracilis muscle flap, must be performed in combination with the fistula repair. For complex repairs involving radiated tissues, the success rate is less than 90%, but, for experienced surgeons, the outcome remains highly successful.

Keep in mind that the first operation is the best one. Any attempts at further surgical repair after an initial failed approach may yield unsatisfactory results. To maximize outcomes and minimize further potential morbidity, it is highly recommended to seek out a surgeon who is adept at this type of reconstruction and performs this in a high volume.

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