Rectovaginal fistulas

By Magdy Abdelrahman mohamed

Lecturer of OB/GYN2016

Rectovaginal Fistula is an abnormalcommunication between the rectum and thevagina .

RVFs are classified on the basis of location,size, and etiology, each of which affects thetreatment plan and prognosis

The rectovaginal septum is the thinseptum separating the anterior rectalwall and the posterior vaginal wall.

The caudal portion of the septum is theperineal body.

The anal sphincters are located in theposterior portion of the perineal body.

A more precise definition is that a lowRVF is between the lower third of therectum and the lower half of the vagina,and a high fistula is between the middlethird of the rectum and the posteriorvaginal fornix.

Low RVFs are closest to the anus and canbe corrected with a perineal approach.High fistulas require a transabdominalapproach for repair

RVFs may vary greatly in size, but mostare less than 2 cm in diameter.

Small-sized fistulas are less than 0.5 cmin diameter, medium-sized fistulas are0.5-2.5 cm, and large-sized fistulas exceed2.5 cm.

Traumatic:

Obstetrical trauma.(commonest)

Surgical trauma.

Direct trauma.

Inflammatory:

Pelvic abscess.

TB.

crohn’s disease.

Neoplastic

post-irradiation.

A few patients are asymptomatic. Mostpatients report passage of flatus or stoolthrough the vagina.

Patients may also experience vaginitis orcystitis.

At times, a foul-smelling vaginaldischarge develops, but frank stool pervagina usually occurs only when thepatient has diarrhea.

The clinical picture may include fecalincontinence due to associated analsphincter damage .

Physical examination is essential. Thisusually confirms the diagnosis andaffords much information regarding thesize and location of the fistula, thefunction of the sphincters, and thepossibility of IBD ( Inflammatory BowelDisease) or local neoplasm.

The suspicion of Crohn’s disease should behigh if there is any other abnormality of therectal mucosa or a previous or currentlycoexisting fistula.

Failure to recognize Crohn disease can lead toinappropriate operative intervention and canworsen the patient's situation

Flexible endoscopy (sigmoidoscopy orcolonoscopy) is used to fully evaluate thepossibility of IBD or malignancy.

When IBD is in the differential diagnosis,endoscopy with biopsies must precede anyoperative approach to the fistula because thetreatment varies, depending upon thediagnosis.

Indications:

Because the symptoms of RVFs are sodistressing, surgical therapy is almost alwaysindicated.

Exceptions include patients who unfit forsurgery.

Treat acute fistulas of traumatic origin(including those caused by obstetric andoperative trauma) and fistulas complicated bysecondary infection or of infectious origin withlocal care, drainage of abscesses, and directedantibiotic therapy.

Allow tissues to heal for 6-12 weeks.

Dietary modification and supplemental fibercan greatly diminish symptoms during thisperiod.

Many fistulas resulting from obstetric oroperative trauma heal completely, requiring nofurther therapy.

RVFs of radiation origin are very difficult totreat surgically, and medical therapy is ofteninitially recommended in this setting. Diet andfiber are the mainstays of therapy.

Preoperative details: Completemechanical bowel preparation &intestinal antiseptics.

Although used in the past, the majorityof RVFs are now repaired without firstperforming a diverting colostomy

Local repair methods

Transanal advancement flap repair:

The best results have been reported with this type ofrepair.

The fistula is identified using the operatinganoscope.

A flap is outlined, extending at least 4 cm superior tothe fistula.

Conversion to complete perineal tear: withlayer closure.

Simple fistulotomy: This procedure workswell for small anovaginal fistulas, in which nosphincter is involved in the tract.

Transabdominal approaches are generally usedfor high RVFs when the fistula originates froma neoplasm, radiation, or, occasionally, IBD.

Fistula division and closure without bowelresection: This is the simplest abdominalapproach. Interposition of healthy tissue, suchas omentum, may be used to separate thesuture lines.

Bowel resection: When tissues are abnormalbecause of radiation, inflammation, orneoplasm.