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 fistulae may mimic symptoms of stress urinary incontinence although it is generally more significant than traditional stress urinary incontinence.
Obstetric trauma and delays in receiving obstetric care are the most common causes of urinary fistulae in medically underserved countries. In developed countries, more than 50% of such fistulae 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 hysterectomy should raise suspicions for vesicovaginal or ureterovaginal fistulae. If vesicovaginal or ureterovaginal fistula is suspected, as an immediate step, collection of vaginal fluid should be encouraged so that it can be sent for fluid creatinine measurement; a fluid creatinine level significantly higher than that of a simultaneous serum creatinine level confirms that the fluid is urine. In addition, a methylene blue dye test is a reliable way to establish the diagnosis of vesicovaginal fistula. [3] Cystoscopy with bilateral retrograde pyelogram is necessary for the diagnosis and differentiation between ureterovaginal and vesicovaginal fistula. A double dye test may also be useful for differentiating vesicovaginal and ureterovaginal fistulae. See Workup.
Once the fistula site has been identified, a ureteral stent for ureterovaginal fistula and urethral catheter for vesicovaginal fistula can be employed for symptomatic relief from the incontinence. Spontaneous closure can occur in up to 15% of cases using stent or catheter drainage. [4] Conservative approaches are more likely to be successful for nonradiotherapy fistulae and smaller fistulae. [4]
For surgical correction of vesicovaginal fistula, the transabdominal and transvaginal approaches are commonly chosen. Historically, the site of the fistula and surgeon familiarity often dictated the surgical approach. Supratrigonal fistulae (fistulas above the interureteric ridge) were typically approached transabdominally. Infratrigonal fistulae (fistulae below the interureteric ridge) were corrected transvaginally. Currently, most surgeons prefer the transabdominal approach for both supratrigonal and infratrigonal fistulas because access to the fistula is easier. Supratrigonal fistulae are more difficult to reach transvaginally.
However, in the setting of an infratrigonal fistula, the transvaginal approach (provided that the surgeon is comfortable with it) is beneficial because it avoids the morbidity from a midline incision. The utilization of laparoscopic and robotic-assisted technology is increasing, particularly in the setting of ureterovaginal fistulae and supratrigonal vesicovaginal fistulae, and has lower morbidity than traditional open approaches. [5]
Fistulae can lead to significant impacts on mental health, and repair has been demonstrated to greatly improve both anxiety and depression scales. [6] Fistula can interfere with sexual function, as women may fear urinary leakage during intercourse or pain with intercourse. Athough repair generally improves sexual function, it can also result in de novo urinary stress or urgency incontinence that may contribute to sustained sexual dysfunction. [7, 8]
Pathophysiology
Unrecognized bladder injury during a difficult hysterectomy or cesarean delivery may result in vesicovaginal fistula formation. Most vesicovaginal fistulae occur when dissection of the bladder during the mobilization of the bladder flap 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. Uncommonly, this can also occur in the setting of an unrecognized duplicated ureter.
Fistulae resulting from vaginal birth 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. Currently, this is rare in the United States; however, it remains common throughout much of the world.
Etiology
In the United States, more than 50% of vesicovaginal and ureterovaginal fistulae 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 therapy is typically used to treat cervical or endometrial carcinoma. Vesicovaginal fistulae and ureterovaginal fistulae may occur with or without cancer recurrence.
In countries with limited resources, obstetrical complications are the most common cause of vesicovaginal and ureterovaginal fistulae. This may develop in cases of long-standing and obstructed labor leading to pressure necrosis on the anterior vaginal wall. Fistulae in this setting may be large and involve extensive local tissue damage and necrosis.
Epidemiology
A systematic review over a 35-year period reported that 83.2% of fistula in developed countries were iatrogenic, whereas 95.2% of fistula in developing countries were the result of obstetric complications. [4] However, the incidence of vesicovaginal fistula resulting from hysterectomy is estimated to be less than 1%. Approximately 10% of such fistulae may involve one or both ureters. Some fistulae may be more complex, involving adjacent organs. If the rectum is involved in the inflammatory reaction, rectovaginal fistulae may develop. [9]
The estimates of the global prevalence of untreated obstetric fistula vary from 654,000 to 3,500,000. In Ethiopia, Malawi, and Bangladesh, reported incidences range 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 1000 births. [10]
Prognosis
The success rate of vesicovaginal and ureterovaginal fistula repair approaches 90% at first attempt and approaches 100% after a second attempt. [11, 12] However, the second operation is more extensive and more complex than the first operation. Often, the surgical approach must be changed, and additional procedures (eg, Martius flap, peritoneal flap, omental flap, or gracilis muscle flap) must be performed in combination with the fistula repair. For complex repairs involving irradiated 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 it in a high volume.
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Vaginal view of vesicovaginal fistula.
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Cystoscopic view of vesicovaginal fistula.
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Cystogram of vesicovaginal fistula. Note the contrast extravasating from the bladder into the vaginal canal.
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This patient developed a supratrigonal vesicovaginal fistula immediately over the right ureteral orifice after transabdominal hysterectomy for uterine fibroids. The right ureteral orifice has been cannulated with a ureteral catheter to prevent injury to the ureteral orifice during the fistula repair. A Foley catheter has been inserted into the bladder. A transvaginal repair was performed.
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Percutaneous suprapubic tube is placed prior to repair of a supratrigonal vesicovaginal fistula.
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The supratrigonal vesicovaginal fistula site is marked out.
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Supratrigonal vesicovaginal fistula. Isotonic sodium chloride is injected into the anterior vaginal wall to facilitate hydrodissection.
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Supratrigonal vesicovaginal fistula. A J-shaped incision is made, and the anterior vaginal wall is dissected off proximally and distally to the fistula. The fistula site is not excised. A generous flap is created anteriorly and posteriorly to the fistula site. Surgical sutures have been placed in the fistula to close the site.
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Supratrigonal vesicovaginal fistula. Surgical sutures are tied, and the fistula is closed.
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Supratrigonal vesicovaginal fistula. Reinforcing tissue layers are used to cover up the fistula site in a nonoverlapping fashion. In this case, peritoneum followed by pubocervical fascia was used.
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Supratrigonal vesicovaginal fistula. Vaginal wall is closed.
