FORT LAUDERDALE, FLA. — Obstetric trauma is the most common cause of rectovaginal fistulas, Eric G. Weiss, M.D., said at a symposium on pelvic floor disorders sponsored by the Cleveland Clinic Florida.
Reported series suggest such trauma accounts for 50%-90% of fistulas, said Dr. Weiss, director of surgical endoscopy and a staff colorectal surgeon at Cleveland Clinic Florida, Weston.
“We don't really have a good way to prevent these—it's just one of those things that can happen after delivery,” he said, noting that such fistulas occur in fewer than 1% of vaginal deliveries.
But for such tiny holes—sometimes the size of a pinhole—these defects can lead to extensive symptoms, and can be very difficult to repair.
Rectovaginal fistulas associated with obstetric trauma usually are the result of unrecognized third- or fourth-degree perineal tears or repairs that break down as a result of infection or hematoma. Other causes include inflammatory bowel disease, infection, and other types of trauma, such as pelvic radiation therapy, Dr. Weiss noted.
A number of treatment options exist, but for simple fistulas—or those that are less than 2.5 cm in diameter, distal, surrounded by otherwise healthy tissue, and caused by trauma or infection—Dr. Weiss' treatment of choice is the transanal endorectal advancement flap.
Reported success rates for this type of advancement flap range from 41% to 100%, and the variation may be explained by differences in the way results are reported. For example, some studies include patients who also underwent sphincteroplasty, which would most likely improve results.
Patients with fistulas associated with obstetric trauma are more likely than other patients to also require sphincteroplasty. In his experience, success rates are generally in the range of 60%-65%, with higher success rates of up to 91% reported in those with an intact sphincter.
Other transanal surgical options include layered closure and the anocutaneous advancement flap, and transvaginal options include fistula inversion and vaginal flap advancement. Reported success rates for these approaches range from 72% to 100%, but findings are based mainly on very small case series.
Surgical failure is usually attributable to infection or hematoma. Prompt drainage and antibiotic therapy for infections may salvage the repair. When necessary, surgical correction can be reattempted, but success rates decline with each successive attempt, Dr. Weiss said.
Repeat surgery should be delayed until inflammation has resolved and the wounds have healed; patients with activity-limiting symptoms may require temporary diversion during this time.
One option for the repair of recurrent rectovaginal fistulas includes perineoproctotomy, which involves re-creation and repair (by closure in layers) of a third- or fourth-degree tear. Success rates are in the 88% to 100% range, and although a downside of this surgery is division of the sphincter muscle, there are no reports of postoperative incontinence in the literature, he noted.
Sphincteroplasty is the best option for those with sphincter injury. Success rates with this procedure also range from 88% to 100%.
Tissue interposition using the Martius procedure (bulbocavernosus interposition) and graciloplasty are other surgical options with reasonable success rates, he noted.
Complex fistulas—or those that are larger than 2.5 cm in diameter and caused by inflammatory bowel disease, malignancy, or radiation—are more difficult to treat, in part because patients often have complicating medical problems.
For high rectovaginal fistulas, transabdominal division of the fistula with resection and primary anastomosis is recommended. An alternative in patients with a normal rectum is division of the fistula and interposition of omentum or muscle.
Temporary diversion may be necessary in patients with a failed transabdominal surgery. If the fistula does not close spontaneously during diversion, repeat resection or interposition of the omentum is recommended, but few data are available to guide decision making regarding surgery in these patients, he said.
For radiation-induced complex fistulas, temporary diversion is usually performed first. Repair is appropriate when the patient is otherwise healthy and has no evidence of recurrent cancer. One option is coloanal anastomosis to bring in healthy tissue to replace the tissue devascularized as a result of the radiation. Other options are the Bricker on-lay patch and muscle interposition.
A number of surgeries, including transvaginal repairs, endorectal advancement flaps, and muscle interposition and resection, have been described in patients with Crohn's disease. Initial failure requires endoscopic evaluation. If proctitis is present, medical treatment or proctectomy are recommended, but if the rectum is not inflamed, a repeat repair may be successful, Dr. Weiss said.