Vesicovaginal fistulas (VVFs) are the most common type of urogenital fistulas – approximately three times more common than ureterovaginal fistulas – and can be a debilitating problem for women.
Most of the research published in recent years on VVFs and other urogenital fistulas comes from developing countries where these abnormal communications are a common complication of obstructed labor. In the United States, despite a relative paucity of data, VVFs are known to occur most often as a sequelae of gynecologic surgery, usually hysterectomy. Estimates of the incidence of VVF and other urogenital fistula formation are debated but have ranged from 0.5% or less after simple hysterectomy to as high as 2% after radical hysterectomy. Most VVFs are believed to occur after hysterectomy performed for benign disease, and many – but not all – are caused by inadvertent bladder injury that was not recognized intraoperatively.
Women who have had one or more cesarean deliveries and those who have had prior pelvic or vaginal surgery are at increased risk. In addition, both radiation therapy and inflammation that occur with diseases such as pelvic inflammatory disease or inflammatory bowel disease can negatively affect tissue quality and healing from surgical procedures – and can lead ultimately to the development of urogenital fistulas – although even less is known about incidence in these cases.
Prevention
Intraoperatively, VVFs may best be prevented through careful mobilization of the bladder off the vaginal wall, the use of delayed absorbable sutures (preferably Vicryl sutures), and the use of cystoscopy to assess the bladder for injury. If cystoscopy is not available, retrograde filling with a Foley catheter will still be helpful.
An overly aggressive approach to creating the bladder flap during hysterectomy and other surgeries can increase the risk of devascularization and the subsequent formation of fistulas. When the blood supply is found to have been compromised, affected tissue can be strengthened by oversewing with imbrication. When an inadvertent cystotomy is identified, repair is often best achieved with omental tissue interposed between the bladder and vagina. If there is any doubt about bladder integrity, an interposition graft between the bladder flap and the vaginal cuff will help reduce the incidence of fistula formation. Whenever overlapping suture lines occur (the vaginal cuff and the cystotomy repair), the risk of VVF formation will increase. Other than that using omentum, peritoneal grafts will also work well.
VVF formation may still occur, however, despite recognition and repair of an injury – and despite normal findings on cystoscopy. In patients who have had prior cesarean deliveries or other prior pelvic surgery, for example, tissue devascularization may cause a delayed injury, with the process of tissue necrosis and VVF formation occurring up to a month after surgery. It is important to appreciate the factors that predispose patients to VVF and to anticipate an increased risk, but in many cases of delayed VVF, it’s quite possible that nothing could have been done to prevent the problem.
Work-up
Courtesy of John Miklos, MD
This drawing shows the location of a typical posthysterectomy fistula.
Vesicovaginal fistulas typically present as painless, continuous urine leakage from the vagina. The medical history should include standard questions about pelvic health history and symptom characteristics (in order to exclude hematuria or leakage of fluid other than urine), as well as questions aimed at differentiating symptoms of VVF from other causes of urinary incontinence, such as stress incontinence. In my experience, urine leakage is often incorrectly dismissed as stress incontinence when it is actually VVF. A high index of suspicion will help make an earlier diagnosis. This does not usually change the management, but helps manage the anxiety, expectations, and needs of the patient.