A rectovaginal fistula (RVF) is an epithelial-lined tract between the rectum and vagina.[1] For thousands of years, women simply tolerated the distressing symptoms generated by RVFs. Today, there is no need for such tolerance, because most RVFs can be surgically corrected via a number of approaches.[2] A small percentage, however, cannot be corrected, because of patient comorbidity or disease-related factors; in these cases, patients can be helped only by fecal diversion.[3]
This article discusses only acquired RVFs. Most RVFs are located at or just above the dentate line. Fistulas below the dentate line are not true RVFs but, rather, anovaginal fistulas; the treatment required for these differs from that required for RVFs.
The rectovaginal septum is the thin septum separating the anterior rectal wall and the posterior vaginal wall. The caudal portion of the septum is the perineal body. The anal sphincters are located in the posterior portion of the perineal body. The transverse perineal muscle traverses the perineal body and is often used in anal sphincteroplasty and RVF repair.
The dentate line is the grossly visible demarcation between the squamous anal epithelium and the transitional-columnar epithelium of the rectum. The anal glands open into the bases of the anal crypts at this location.
The lowest extent of the peritoneal cavity in the female lies in the pelvis and may be anterior to the cervix uteri, posterior to it, or both. The occupation of this space by the small bowel is called an enterocele; when the space is occupied by the sigmoid colon, this is termed a sigmoidocele.
Several traumatic mechanisms for the development of RVF exist. Perineal lacerations during childbirth, especially those due to episioproctotomy, predispose patients to RVFs. Perineal lacerations are more common in primigravidas, in precipitous births, or when forceps or vacuum extraction is used. Failure to recognize and correctly repair perineal lacerations, or secondary infection of perineal lacerations, further increases the chance of RVF. Prolonged labor with pressure on the rectovaginal septum can produce necrosis and result in RVF.
Vaginal or rectal operative procedures, especially those performed near the dentate line, may cause RVFs. Stapled hemorrhoidopexy, STARR (stapled transanal rectal resection), and TRANSTAR (transanal stapler-assisted resection) have been increasingly associated with RVFs.[4] Pelvic operations can be complicated by the development of a high RVF.
Traumatic injury (penetrating or blunt) and forceful coitus also have produced RVFs.
Crohn disease[5] and, less often, ulcerative colitis have been associated with RVFs. The fistula may arise primarily or, more often, in relation to a perirectal abscess or fistula, manifesting as complicated perianal sepsis.
The use of radiation to treat pelvic malignancies may give rise to RVFs.[6] Fistulas that occur during such therapy usually result from tumor regression. Most other fistulas become apparent 6 months to 2 years after completion of treatment. Diabetes, hypertension, smoking, and previous abdominal or pelvic surgery increase the risk of fistula formation. The use of biopsy to differentiate radiation-related change at the fistula from a recurrent tumor is imperative, because neoplasms (primary, recurrent, or metastatic) can produce RVFs.
A variety of infectious conditions can produce RVF. The most common are perirectal abscess/fistula and diverticulitis. Less commonly, tuberculosis, lymphogranuloma venereum, and Bartholin gland abscess can cause RVFs.
Among reported series, the frequency with which RVFs occur varies according to the cause. RVFs are classified on the basis of location, size, and etiology (see Etiology), each of which affects the treatment plan and prognosis.
RVFs can be divided into the following two groups on the basis of location:
RVFs may vary greatly in size, but most are less than 2 cm in diameter. They are stratified by size as follows:
The most common etiology for RVF of traumatic origin, and probably for all RVFs, is obstetric injury.[7, 8] Other etiologies for RVF include the following:
Transanal advancement flap repair is a very safe approach. Results are good to excellent, with success reported in 77-100% of patients in various series. Preoperative assessment of anal sphincter integrity is important. Sphincter repair is easily performed simultaneously and increases the success rate of RVF repair. Vaginal childbirth after RVF repair is not associated with an increased risk of RVF recurrence. However, if a sphincter repair is performed along with the RVF repair, many surgeons recommend cesarean delivery for subsequent pregnancies in order to avoid disruption of the sphincteroplasty.
Transvaginal inversion repair and conversion to complete perineal laceration with layer closure can yield acceptable results in selected cases.
Bioprosthetic repair is a newer technique for RVF repair. Early experience indicates that it produces results that are equal or superior to those of advancement flap repair.[9] The button fistula plug has been successful in 58% of rectovaginal and ileal pouch–vaginal fistulas.[10]
Simple fistulotomy is suitable only for true anovaginal fistulas, which incorporate no sphincter muscle whatsoever. Application of this technique to RVF results in incontinence.
With approximation of healthy tissue in the absence of inflammation, infection, or tension, transabdominal repairs yield good long-term results. It is essential always to consider the morbidities of major abdominal surgery and any comorbid conditions related to the patient's history.
Patients with fistulas due to radiation may have added morbidities associated with other irradiated tissues, such as the following:
Recurrence of an RVF indicates a poorer prognosis for future repair attempts.[11] In a study by Schouten et al, rectal sleeve advancement had an overall healing rate of 75% for persistent RVFs.[12] Recurrence is influenced by the etiology of the fistula and by its complexity. Fistulas of obstetric origin and fistulas that are considered simple (rather than complex) fare better after repeated repair attempts.
Byrnes et al, in a retrospective cohort study assessing the outcomes of primary surgical repair of RVF in relation to fistula etiology and specific surgical approach, found that the surgical approach affected recurrence-free survival at 1 year, with a rate of 35.2% forr the local approach, 55.6% for the transvaginal or endorectal approach, 95% for the abdominal approach, and 33.3% for diversion only.[13] Fistula etiology did not significantly affect recurrence-free survival.
The clinical presentation of rectovaginal fistula (RVF) varies little. A few patients are asymptomatic, but most report the passage of flatus or stool through the vagina, which is understandably distressing. Patients may also experience vaginitis or cystitis. At times, a foul-smelling vaginal discharge develops, but frank stool through the vagina usually occurs only when the patient has diarrhea. The clinical picture may include fecal incontinence due to associated anal sphincter damage or bloody, mucus-rich diarrhea caused by the underlying clinical etiology.
Physical examination is essential. This usually confirms the diagnosis of RVF and provides a great deal of information regarding the size and location of the fistula, the functioning of the sphincters, and the possibility of inflammatory bowel disease (IBD) or local neoplasm. (Anal sphincter disruptions are commonly seen in association with RVFs of obstetric origin. Sphincter function should be evaluated prior to any repair.)
Office examination usually consists of a rectovaginal examination (visual and palpation) and proctosigmoidoscopy. The fistula opening may be seen as a small dimple or pit and occasionally can be gently probed for confirmation.
The suspicion of Crohn disease should be high if there is any other abnormality of the rectal mucosa or a previous or currently coexisting fistula-in-ano. Failure to recognize Crohn disease can lead to inappropriate operative intervention and can worsen the patient's situation.
Placing a vaginal tampon, instilling methylene blue into the rectum, and examining the tampon after 15-20 minutes can often establish the presence of RVF. If the tampon is unstained, another part of the gastrointestinal (GI) tract may be involved.
Laboratory studies (eg, complete blood count [CBC], blood cultures, electrolytes, blood urea nitrogen [BUN], creatinine, and type and screen) are obtained to assess for sepsis, which is extremely rare in fistulas between the gastrointestinal (GI) tract and the female genital tract. Laboratory studies are also helpful in the establishment of preoperative baselines.
Ancillary studies may illustrate a rectovaginal fistula (RVF) that is elusive on physical examination.[14] Barium enema can demonstrate RVF or the more common sigmoid-vaginal cuff fistula observed in diverticulitis. Computed tomography (CT) often shows perifistular inflammation, identifying the responsible digestive organ. Endorectal and transvaginal ultrasonography (US) may be used to help identify low fistulas. Magnetic resonance imaging has been employed in the diagnosis of RVFs.[15]
Flexible endoscopy (sigmoidoscopy or colonoscopy) is used to fully evaluate the possibility of inflammatory bowel disease (IBD). Because treatment varies according to the diagnosis, endoscopy with biopsies must precede any operative approach to the fistula when IBD is in the differential diagnosis.
Histology is most important in the evaluation of possible IBD. Neither a diagnosis of ulcerative colitis nor a diagnosis of Crohn disease completely excludes operative repair of an RVF, but operative planning is altered, as is the prognosis. If the rectum is grossly normal in Crohn disease, the prognosis of RVF repair is fair; if the rectum is abnormal, the prognosis is considerably worse. With any fistula considered suggestive of a primary or recurrent neoplasm, the histopathology is of the utmost importance.
Because the symptoms of rectovaginal fistula (RVF) are so distressing, surgical therapy is almost always indicated. Exceptions include patients who are moribund and those for whom the proposed anesthesia and surgery pose prohibitive risks. Note that surgical therapy means repair in most cases. Some patients, however, are better served by a diverting stoma than by an ill-advised repair attempt.
Guidelines for management of RVF have been developed by the American Society of Colon and Rectal Surgeons (ASCRS; see Guidelines).[16]
Use local care, drainage of abscesses, and directed antibiotic therapy to treat acute RVFs of traumatic origin (including those caused by obstetric[7, 8] and operative trauma), RVFs complicated by secondary infection, and fistulas of infectious origin. Allow tissues to heal for 6-12 weeks. Dietary modification and supplemental fiber can greatly diminish symptoms during this period.
Many fistulas resulting from obstetric or operative trauma heal completely, requiring no further therapy. When the fistula persists after this period of treatment and the tissues become uninflamed and supple, repair may be considered.
Perform a biopsy on any area suggestive of neoplasm. Treat neoplasms as appropriate. In this setting, highly symptomatic fistulas may prompt the physician and patient to consider a diverting colostomy for patient comfort. Otherwise, fecal diversion is rarely used with RVFs.[3]
If the evaluation is consistent with the diagnosis of inflammatory bowel disease (IBD), institute appropriate medical therapy. Repair of an RVF can be performed while the patient is on steroid therapy, with the understanding that the risk of failure is increased. Even after initial failed repair attempts, some patients with Crohn disease can maintain RVF repair while on antimetabolites, such as 6-mercaptopurine or azathioprine. Clinical use of infliximab[17, 18] suggests that few fistulas heal completely, but most patients experience dramatic improvements in their symptoms.
Predictors of failure necessitating fecal diversion have been identified and include significant colonic involvement and the presence of anal stricture.[3] The development of carcinoma has been described in Crohn fistulas.[19]
RVFs originating from radiation therapy are very difficult to treat surgically,[6] and medical therapy is often initially recommended in this setting. Diet and fiber are the mainstays of treatment.
Surgical treatment is almost always indicated. Typically, such treatment consists of repair via either a local or a transabdominal approach (see below).
Minimally invasive approaches have been described.[20] Mukwege et al applied a laparoscopic approach to the treatment of high RVFs in 10 patients and reported a clinical success rate of 90% (median follow-up, 14.3 months).[21] Lamazza et al used endoscopic placement of a self-expanding metal stent to treat 10 patients with RVF after colorectal resection for cancer. At follow-up (mean, 24 months), eight RVFs had healed without major fecal incontinence; the other two had been reduced sufficiently to allow a flap transposition.[22]
Complete mechanical bowel preparation is essential for transabdominal repair of RVF and is also recommended for local repair. The practice of including poorly absorbed oral antibiotics in the bowel preparation is under scrutiny. Data suggest that administering intravenous (IV) antibiotics in such a way as to ensure appropriate tissue levels at the start of the procedure is sufficient for prophylaxis. The author recommends that prophylactic IV antibiotics be given preoperatively to all patients undergoing RVF repairs, whether transabdominal or local.
Although diverting colostomy was used in the past, the overwhelming majority of RVFs are now repaired without this procedure being performed beforehand.
Cleanse the vaginal lumen with an antiseptic solution, such as povidone-iodine. Insert a catheter into the urinary bladder.
If a transabdominal procedure is planned, perform standard preoperative cardiopulmonary evaluation as appropriate. Prophylaxis against venous thromboembolism is essential and may include the use of fractionated or unfractionated heparin, as well as the employment of sequential compression devices. If the pelvis has been irradiated or previously operated on, the use of ureteral catheters may aid in dissection.
Transanal advancement flap repair
The best results have been reported with transanal advancement flap repair.[23] General, regional, or local anesthesia may be used. The patient is placed in the prone, flexed position with a hip roll in place; the buttocks are taped apart for exposure.
The fistula is identified using the operating anoscope. A flap is outlined, extending at least 4 cm cephalad to the fistula, with the base of the flap twice the width of the apex to allow adequate blood supply to the flap tip. Local anesthetic with epinephrine is injected submucosally to facilitate raising the flap and to diminish bleeding.
The flap, consisting of mucosa and submucosa, is raised; some surgeons include circular muscle as well. Meticulous hemostasis is imperative. The fistula tract is curetted gently. Circular muscle is closed over the fistula. The tip of the flap, which includes the fistula opening, is excised. The flap is sutured in place with simple interrupted absorbable sutures, effectively closing the rectal opening of the fistula. The vaginal side of the fistula is left open for drainage.
This approach separates the suture line from the fistula site and interposes healthy muscle between the rectal and vaginal walls. Proponents point out that the relatively high pressure within the rectum serves to buttress the repair, in contrast to a transvaginal repair, in which the intrarectal pressure is more prone to disrupt the repair. If indicated, sphincteroplasty can be performed concomitantly.[24]
Transvaginal inversion repair
The vaginal mucosa is circumferentially elevated, exposing the fistula. Two or three concentric purse-string sutures are used to invert the fistula into the rectal lumen. The vaginal mucosa is reapproximated. This approach has generally been considered suitable only for small, low fistulas in otherwise healthy tissues with an intact perineal body. It is rarely performed today.
Bioprosthetic repair
A bioprosthetic interposition graft is placed by making a transverse incision over the midportion of the perineal body with dissection through the subcutaneous tissue. The fistula tract is transected. The dissection is continued 2 cm proximal to the transected fistula tract and laterally. The fistula openings are closed with 3-0 interrupted absorbable sutures.
The graft requires an overlap of 2 cm on all sides of the rectal and vaginal mucosal closures. A bioprosthetic plug is placed through the rectal opening and out the vaginal opening. The excess plug is trimmed and secured on the rectal side with 2-0 absorbable suture.
Conversion to complete perineal laceration with layer closure
In a conversion to complete perineal laceration with layer closure,[3] the fistulous tract is laid open in the midline, essentially creating a cloaca. Closure in layers follows, identical to the classic obstetric repair of a fourth-degree perineal laceration. This method is described in the gynecologic literature; it is rarely employed by colorectal surgeons, because of concerns about juxtaposed suture lines.
Simple fistulotomy
Simple fistulotomy works well for true anovaginal fistulas, in which no sphincter is involved in the tract. If the technique is used to treat an RVF, however, partial or total fecal incontinence results.
Transabdominal approaches are generally used for high RVFs when the fistula originates from a neoplasm, from radiation, or, occasionally, from IBD. They are also used if concomitant disease (eg, diverticulitis) warrants an abdominal approach.
Fistula division and closure without bowel resection
This is the simplest abdominal approach. The rectovaginal septum is dissected, the fistula is divided, and the rectum and vagina are closed primarily without bowel resection. Interposition of healthy tissue, such as omentum, may be used to buttress the repair and separate the suture lines. Good results have been reported when the fistula is not large and the tissues available for closure are healthy.
Bowel resection
When tissues are abnormal because of irradiation, inflammation, or neoplasm, the repair is doomed to failure unless the abnormal tissues are resected. Preserve functional anal sphincters whenever possible by use of a low anterior resection, a coloanal anastomosis technique, or a pull-through; the last alternative has the poorest results with respect to continence.
Rarely, abdominoperineal resection may be necessary for symptom control in the setting of radiation damage or neoplasm. An alternative, particularly in cases of poor operative risks or with patients whose survival is limited, is simple fecal diversion with a loop ileostomy or colostomy.
Ancillary procedures
A host of supplementary procedures have been described to augment bowel resection in the difficult pelvis. These include local flaps, such as the bulbocavernosus flap, and a variety of muscle, fascial, and musculocutaneous flaps for repair of large pelvic defects. A variety of graft procedures also have been described.[25] All of these procedures have the goal of interposing healthy tissue between vaginal and rectal repairs. They are well described in the plastic surgery literature.
The onlay Bricker patch also has been used to repair RVFs, chiefly those produced by radiation. Briefly, the rectosigmoid colon is mobilized transabdominally, and the RVF is exposed. The rectosigmoid is divided above the fistula. The proximal end is brought out as an end sigmoid colostomy. The distal rectosigmoid is turned down, and the open end is anastomosed to the debrided edge of the rectal opening of the fistula, essentially creating an internal loop with drainage through the anus.
When healing of the inferior-patched rectum can be demonstrated radiologically several months later, continuity of the colon is reestablished by anastomosis of the colostomy to the apex of the patch loop in an end-to-side fashion.
An advantage to this procedure is that it is less difficult than resection and therefore may be less likely to cause hemorrhage or organ injury. A disadvantage is that the radiation-damaged rectum is left in place and in use, with the possibility of further morbidity, including bleeding and stricture.
Although situations exist where this approach may be preferable to a resection approach, the author believes that resection of the radiation-damaged bowel provides the best long-term results in patients who are reasonable operative candidates.
Tong et al reported results from a nonrandomized prospective monocentric study of 16 consecutive patients (median age, 40.1 years) who underwent RVF repair with the Over-The-Scope Clip Proctology system.[26] The primary outcome was RVF healing at 8 months; assessment of morbidity and timing of RVF recurrence were secondary outcomes. Seven of the 16 patients (43.7%) had successful primary healing of the fistula. Short-term complications were rare: Four patients experienced pain, and two had spontaneous clip detachment. Most recurrences developed shortly after the procedure (median delay, 45 days; range, 16-217).
RVFs associated with Crohn disease are difficult to manage.[5, 27] When symptoms are few, operative intervention may not be indicated. Conversely, severely symptomatic patients may require proctectomy.
Patients with relatively normal rectal mucosa and an RVF are good candidates for an endorectal advancement flap. In this specific setting, outcome is good, though not as good as in patients without Crohn disease. An endorectal advancement flap is considered the preferred technique for local RVF repair in patients with Crohn disease and a relatively normal rectum.
A multivariable logistic regression model identified immunomodulators as being associated with successful healing and smoking and steroid usage as being associated with failure.[28]
Attention must be paid to the patient's bowel habits. Constipation or diarrhea can disrupt a repair. The goal is a soft, formed, deformable stool. The patient is carefully counseled regarding diet, copious fluid intake, and the use of stool softeners. The use of bulking agents immediately after repair is at the discretion of the surgeon and is a matter of individual preference rather than of scientifically proven practice. The use of oral antibiotics also varies.
The author prefers that patients use an oral broad-spectrum antibiotic for 3-5 days postoperatively, take 1 tablespoon of mineral oil orally twice daily for 2 weeks postoperatively, and avoid bulking agents for 2 weeks postoperatively. Patients need to refrain from sexual activity or any physical activity more strenuous than a slow walk for 3 weeks.
Postoperative care after transabdominal repair is identical to the care administered to all patients who have undergone major laparotomy with bowel resection and anastomosis. Postoperative gastric decompression is performed selectively, in the expectation that 15-20% of patients require cessation of oral intake or gastric decompression for symptomatic postoperative ileus. Most patients can be offered sips of clear liquids on postoperative day 1.
Early ambulation is beneficial in many ways. Continue perioperative prophylaxis for thromboembolic events until the patient is ambulating well.
Bleeding is rarely encountered postoperatively, probably because of careful intraoperative hemostasis. If bleeding occurs beneath the flap, fistula recurrence is common. Infection is a feared complication, because it almost invariably results in a failed repair. However, good data on the incidence of infection after local repair are few. Of course, repairs may fail in the absence of infection as well (see Prognosis). Rarely, postoperative pain precipitates urinary retention.
These may include the usual complications of any laparotomy with bowel resection, including fistula recurrence. The most common complications are bleeding and wound infection, each with an incidence of less than 2-5% in reasonable-risk candidates. Pelvic abscess occurs in 5-7% of patients. Data from the United States and Europe suggest that anastomotic leaks occur more often than is clinically recognized. However, because intervention is indicated only in clinically evident leaks, routine postoperative anastomotic evaluation is not warranted.
Patients are seen 2 weeks after discharge for evaluation of wounds and bowel habits. In the absence of recurrent fistula symptoms or other specific indications, no follow-up investigation, aside from physical examination, is required.
If specific signs and symptoms are present, they are investigated appropriately. For example, fever, diarrhea, and low abdominal pain indicating an abscess are evaluated by means of computed tomography (CT) of the abdomen and pelvis. In this setting, physical examination may be difficult because of patient discomfort.
In 2016, the American Society of Colon and Rectal Surgeons (ASCRS) published the following guidelines on the management of rectovaginal fistula (RVF)[16] :