A genitourinary fistula is defined as an abnormal communication between the urinary (ureters, bladder, and urethra) and the genital (uterus, cervix, and vagina) systems. The true incidence of genitourinary fistula is unknown, although the generally accepted incidence approximates 1 percent or less of all genitourinary operations.This is most likely an underestimation because many are unreported or unrecognized. The most common type of genitourinary fistula is the vesicovaginal fistula. Vesicovaginal fistulas can also be characterized by their size and location in the vagina. They are termed high vaginal when found proximally in the vagina, low vaginal when noted distally, or midvaginal when identified centrally. Post-hysterectomy
vesicovaginal fistulas are often proximal or high in the vagina, and located at the level of the vaginal cuff. Alternatively, some have classified vesicovaginal fistulas based on the complexity and extent of involvement (Elkins, 1999). In this scheme, complicated vesicovaginal fistulas are those that involve pelvic malignancy, prior radiation therapy, shortened vaginal length, or bladder trigone, or are distant from the vaginal cuff or greater than 3 cm in diameter.
In obstetric classification, high-risk vesicovaginal fistulas are described by their size (greater than 4 to 5 cm in diameter); involvement of urethra, ureter, or rectum; juxtacervical location with an inability to visualize the superior edge; and reformation following a failed repair.
Occasionally, genitourinary fistulas may spontaneous close during continuous bladder drainage using an indwelling urinary catheter. In 10 percent of cases, urinary fistulas close spontaneously after 2 to 8 weeks of transurethral catheterization, especially if the fistula is small (2 to 3 mm diameter). Small fistulas up to 2 cm in diameter spontaneously healed in 50 to 60 percent of patients treated with an indwelling catheter. If the fistula has not closed within 4 weeks, however, it is unlikely to do so, probably secondary to collagen deposition and epithelialization of the fistulous tract.Moreover, continued urinary drainage may lead to further
inflammation and irritation of the bladder. Fibrin sealant has been described for the treatment of vesicovaginal fistula. However, its use has been limited to an adjunctive capacity rather than primary surgical treatment.
Route of Surgical Repair
Among important surgical considerations,
ability to gain access to the fistula is essential and commonly dictates surgery selection. Fortunately, success rates are high
whether the route of repair is transvaginal or transabdominal.
The transvaginal approach to genitourinary fistula repair is straightforward and direct. Compared with abdominal approaches, it is
associated with shorter operative times, decreased blood loss, less morbidity, and shorter hospital stays.The transvaginal route also allows the use of ancillary equipment, such as ureteral stents. This is particularly useful if the fistula is located near ureteral orifices.
The Latzko technique has been likened to a partial colpocleisis.
Typically, it surgically apposes the most proximal portions of the anterior and posterior vaginal walls and thus partially obliteratesthe uppermost vagina. Since vaginal depth is potentially compromised, this technique is not an appropriate option if preservation of
vaginal depth and retention of sexual function are desired.
In contrast to the Latzko method, the classical technique involves excision of the fistulous tract. After excision of the fistula, the vaginal epithelium is undermined and widely mobilized. The bladder mucosa is closed, followed by subsequent closure of two layersof fibromuscular tissue. A watertight repair is confirmed and the vaginal epithelium is reapproximated.
Difficult fistulas or those requiring supravesical urinary diversion require an abdominal approach.The fistula is accessed through an intentional cystotomy. Similar to the transvaginal approach, the bladder and vaginal epithelia at the fistula site are undermined for approximately 1.5 cm in all directions. After adequate mobilization, the fistula site is closed in layers. This approach is used in situations in which: (1) the fistula is located proximally ina narrow vagina; (2) it is in close proximity to the ureteral orifices; (3) a concomitant ureteric fistula is present; (4) previous
repairs of the fistula have been unsuccessful and the fistula is recurrent; (5) the vaginal walls are rigid with little mobility; (6) thefistula is large or complex in configuration; or (7) there is a need for an abdominal interposition graft.
Evidence-based support for laparoscopic genitourinary fistula repair has been limited to case reports and expert opinion.The technique was first described in 1994 by Nezhat and requires advanced laparoscopic surgical skills. As a result, success with this approach appears to be highly dependent on surgeon expertise and experience.
Viability of the surrounding tissue is an important consideration in the repair of genitourinary fistula. When intervening tissues for fistula closure are weak and poorly vascularized, various tissue flaps may be placed vaginally or abdominally between the bladder and the vagina to lend support and blood supply. Interposition flaps are useful in situations in which tissue viability is in question. However, their utility in uncomplicated cases of vesicovaginal fistula is unclear.
Urethrovaginal and Other Genitourinary Fistulas
Although vesicovaginal fistulas are the most common type of genitourinary fistula, other fistulas can exist and may be described based on their communication between anatomic structures. Urethrovaginal fistulas commonly result from surgery involving the anterior vaginal wall, in particular, anterior colporrhaphy and urethral diverticulectomy. As with
vesicovaginal fistula, obstetric trauma remains the most common cause of urethrovaginal fistulas in developing countries. Here, prolonged labor with ensuing tissue necrosis results in development of fistulas. Frequently, patients present with continuous urinary drainage into the vagina or with stress urinary incontinence. The principles of repair are similar: layered closure, tension-freerepair, and postoperative bladder drainage. Other types of genitourinary fistula can also occur
A urethral diverticulum is a cystic enlargement of a paraurethral gland, which is found in the anterior vaginal wall and communicates directly with the urethra. Often fluid filled, this outpouching of the urethra is commonly asymptomaticand frequently diagnosed incidentally on routine examination. However, many present with symptoms and often require Surgery.
Rectovaginal fistulas are abnormal epithelial-lined connections between the rectum and vagina. They can be quite bothersome to both the patient and the surgeon due to their irritating and embarrassing symptoms and high failure rate after repair.
Fistulas can be the result of congenital malformations or acquired etiologies. In this article, we will address acquired rectovaginal fistulas.
Rectovaginal fistulas may be caused by childbirth. Prolonged labor with necrosis of the rectovaginal septum or obstetric injury with a third- or fourth-degree perineal tear or episiotomy can lead to rectovaginal fistula. Inadequate repair, breakdown of the repair, or infection can all result in fistula development. Fortunately, rectovaginal fistula from childbirth is less common in developed countries.
Infectious processes within the rectovaginal septum can also result in a rectovaginal fistula. Cryptoglandular anorectal abscesses and Bartholin gland infections may spontaneously drain causing a low rectovaginal fistula. Diverticular disease in the setting of previous hysterectomy is the most common infectious cause of a high fistula. Cases of rectovaginal fistula as a result of tuberculosis and lymphogranuloma venereum have also been reported.
Malignancies may cause rectovaginal fistulas. These are usually seen in the setting of rectal, uterine, cervical, or vaginal malignancies that have significant local extension or have been treated with radiation therapy. Following radiation therapy, the patient may develop proctitis followed by ulceration of the anterior rectal wall. Rectal ulcers then progress to fistula formation around 6 months to 2 years posttherapy. The incidence of rectovaginal fistula increases with high-dose radiation and previous hysterectomyIf suspicion for an undiagnosed malignancy is present, biopsy of the fistula should be undertaken.
Operative trauma can result in rectovaginal fistula. Low fistulas may be the result of anorectal and vaginal operations. Low stapled colorectal anastomoses may cause a fistula if the vaginal wall becomes incorporated in the stapler or if an anastomotic leak leads to abscess that then drains into the vagina. Alternatively, pelvic procedures may result in high rectovaginal fistulas. Hysterectomy following radiation treatment or with unrecognized intraoperative rectal injury may result in fistula development.
Inflammatory bowel disease is another possible culprit. Both ulcerative colitis and Crohn disease can be associated with rectovaginal fistula. Crohn disease is more frequently associated with rectovaginal fistula because it causes transmural inflammation of the rectal wall. The incidence may increase with the severity of a Crohn’s flare-up, with one study noting an increase in incidence from 0.2% with mild flares to 2.1% with severe attacks. In Crohn disease, rectovaginal fistulas can precede intestinal symptoms.Rectovaginal fistula may occur in ulcerative colitis patients after ileo-anal pouch anastomoses with associated anastomotic leak or pelvic abscess.
A small subset of patients may respond to medical optimization. This usually includes regulating bowel function and controlling diarrhea. Patients with rectovaginal fistula of obstetric origin may experience fistula healing with this regimen. Unfortunately, most women have persistent symptomatic disease that will not heal without surgical intervention.
Timing is an important part of the surgical decision-making process. In the face of infection or inflammation, it is critical to allow resolution prior to repair. Antibiotic therapy or immunosuppressive medications play an important role for surgical preparation. A recommended period of 3 to 6 months for medical therapy has been suggested, but if surrounding tissues appear healthy prior to this, it is reasonable to proceed with surgical repair. Some fistulas may even close spontaneously during this time.
Preoperatively, the patient undergoes mechanical bowel preparation and receives antibiotics. Procedures may be performed under local anesthetic with sedation, but spinal or general anesthesia is typically preferred. Patients are placed in a prone jackknife or left lateral (Simms’) position with exposure obtained by taping the buttocks or using a Lone Star retractor. Patients who require abdominal procedures are placed in the lithotomy position.
Simple Rectovaginal Fistulas
Advancement flaps are the most popular transanal procedure among colorectal surgeons. Many variations exist; however, the general principle remains the same—excision and closure of the rectal portion of the fistula and coverage with a vascularized mucosal flap on the high pressure side of the fistula. The tract is identified by palpation and probing. The fistula tract is débrided and excised. A flap is created that includes mucosa, submucosa, and muscle placed over reapproximated rectovaginal septum. The flap base should be at least 2 to 3 times the width of the apex to ensure adequate vascular supply. Flap mobilization should continue 4 to 5 cm cephalad to the fistula defect. These principles ensure a tensionless suture line. success rates vary from 29 to 100%. This wide discrepancy may be explained by differences in technique as well as patient selection. Complications are rare and minor, including fever, urinary tract infection, and spinal headaches.
Two newer approaches that were developed for the treatment of intersphincteric anorectal fistulas have been adopted for treatment of simple rectovaginal fistulas. One approach involves the use of a bioprosthetic fistula plug made from porcine intestinal submucosa (Anal Fistula Plug, Cook Surgical Inc., Bloomington, IN). After management of local sepsis with drainage procedures, a tapered plug is placed through the rectovaginal fistula tract. Excess plug length is excised at both the rectal and vaginal ends. The plug is then secured with 2–0 absorbable suture in a figure-of-eight fashion on the rectal side and the vaginal side left open to drain. Experience with this technique in patients with rectovaginal fistula is limited.Trials that compare rectal mucosal flap advancement to bioprosthetic plug placement for the treatment of fistula in ano are ongoing. Smaller studies show that bioprosthetic plugs are more successful in the treatment of simple compared with complicated anorectal fistulas.Recent modifications to the bioprosthesis to accommodate anatomic features of a rectovaginal fistula may make this approach more successful.however, additional experience is needed to determine the utility of bioprosthetics in the use of rectovaginal fistula treatment.
A second recently popularized surgical treatment for fistula in ano has been adopted to treat rectovaginal fistula. The procedure which is coined LIFT (ligation of intersphincteric fistula tract), involves dissection in a bloodless plane between the internal and external anal sphincters beyond the fistula tract. The tract is then ligated and closed on both the rectal and perineal side. The intersphincteric dissection is then closed at the skin. High success rates after LIFT treatment of fistula in ano are encouraging (60–94%), but experience with LIFT treatment of rectovaginal fistula is limited. The bioprosthetic plug and LIFT repair for both rectovaginal fistula and fistula in ano are attractive because they allow the surgeon to avoid anal sphincter muscle division. Long-term impact on fecal continence in patients with other risk factors for incontinence remains a high priority for both patient and surgeon.
Complex Rectovaginal Fistulas
Due to the abnormal surrounding tissue, high location, and large size of complex fistulas, attempts at local repair are fraught with failure. The unhealthy tissue must be removed and new, viable tissue introduced to correct the problem. This is usually accomplished with abdominal resection procedures or tissue interposition techniques. Low anterior resection is one option. This allows for resection of diseased bowel and colon anastomosis below the level of the fistula. Abdominoperineal resection or pelvic exenteration may be necessary in the presence of extensive malignancy. Rectovaginal fistula repair should be postponed in the face of inflammation. This is especially important for postradiation fistulas and those caused by inflammatory bowel disease. Initially, diverting loop colostomy or ileostomy with concomitant medical therapy allows for resolution of inflammation. A subsequent rectovaginal fistula repair can then be performed with greater success. Tissue interposition through a perineal approach may be appropriate for high-risk surgical patients. Advantages include avoidance of a high-risk abdominal procedure; however, the disadvantage is that damaged tissue may be left in the surgical field. Options for tissue interposition using a perineal approach include a labial fat pad, bulbocavernous muscle, and pedicled muscle flaps (rectus, sartorius, and gluteal muscles), as well as bioprosthetic materials. The actual surgical approach in patients with complex rectovaginal fistulas should be individualized to each patient.
Management of rectovaginal fistulas in patients with Crohn disease has improved secondary to advances in medical therapy. Control of inflammation has allowed some patients to be treated with local repair techniques. Advancement flap success rates have recently approached 60 to 70%. The failure rate is still considered high, and nearly 50% may need additional surgical treatment. Patients with refractory proctitis, anal stricture, and rectovaginal fistula require permanent ostomy placement, proctectomy, and fistula repair. Symptomatic ulcerative colitis that has failed medical management is treated with total proctocolectomy. Complicated ulcerative colitis with associated rectovaginal fistula may also be treated in this manner. Restoration of continence can be performed with ileo-anal pouch construction, although the pouch-to-sphincter anastomosis must be separated from a rectovaginal fistula repair.