Rectovaginal fistulae (RVFs)

Fistulae between the rectum and the vagina (RVFs) are less common than those between the bladder and the vagina (VVFs). When a patient has a large VVF, she often has an RVF too, because both fistulae are caused in the same way[md]by pressure from the presenting part during a neglected obstructed labour. This causes the adjacent rectal and vaginal walls to necrose; as they heal they unite to form a fistula.

The diagnosis is obvious[md]faeces start to leak through a patient's vagina 2 to 4 days after an obstructed labour, as necrotic tissue starts to separate. To distinguish an RVF from a third-degree tear, clean away her faeces, and look at her perineum. Closing an RVF can be very difficult, because it is so difficult to get at. If you have not repaired one before, make your decision to do so in her best interests. How difficult will it be to repair her, or to refer her? If you cannot refer her, you may have to try to ]]repair her yourself. Unless someone repairs her fistula, she will have to remain with a permanent colostomy.

RECTOVAGINAL FISTULAE Keep the patient in hospital, and give her salt baths three times a day. If possible refer her. Only if you cannot refer her, consider proceeding as follows.

Make a defunctioning sigmoid colostomy (9.5) as soon as the diagnosis is made, and her condition is satisfactory. Continue with salt baths for about 6 weeks.

ASSESSMENT. Under general anaesthesia explore her vaginally, pass a proctoscope, and, if necessary, a sigmoidoscope to see her RVF. How big is it? Is it clean, with all slough gone? Are its edges oedematous? Decide if it will be easier to close from above or below. If you are going to refer her, do so now, while her tissues are healthy. Delay may lead to the formation of fibrous tissue round the fistula, but less so than with a VVF.

If her fistula is at her pelvic brim (common), plan to repair it from above.

If her fistula is within easy reach vaginally (up to 8 cm from her fourchette, less common), plan to repair it from below.

If she also has a VVF, repair this first. Now that she has a colostomy, faeces no longer leak into her vagina.

REPAIR FROM ABOVE [s7](common) ANAESTHESIA. (1) General anaesthesia and intubation, with a relaxant if possible. (2) Subarachnoid (spinal) anaesthesia. Blood for transfusion is usually not necessary, but should be available. Pass a nasogastric tube.

POSITION. Lay her supine with a 5 or 10[de] head-down tilt. Stand on her left.

INCISION. Make a left lower paramedian or subumbilical midline incision. Carefully pack her gut out of the way with a large damp pack, marked by a tape, to which a haemostat is attached.

You will recognize the RVF as the place where her rectum is fixed to her vagina, and often to her bladder also, perhaps with considerable fibrosis. The attachment of her rectum to her bladder may obscure her upper vagina. Use fine curved dissecting scissors to separate her rectum from her vagina. As you do this, you will open into the fistula. As you separate her rectum from her bladder and vagina, avoid cutting through any normal tissue[md]or you may create another fistula! The area is rather inaccessible, because an RVF usually lies at the brim of the pelvis and extends into it.

Freshen the edges of the rectal wound and close it transversely with continuous ''0' chromic catgut on a 5/8 atraumatic needle. If it is large, this may be difficult, but avoid closing it longitudinally, because this will narrow her rectum.

If access to her vaginal defect is easy, close it. Otherwise leave it. It will heal spontaneously, now that her rectal defect is closed.

REPAIR FROM BELOW [s7](uncommon) ANAESTHETIC. Give her a general anaesthetic. Blood is not often necessary, but it should be available.

Lay her supine in the lithotomy position, and work through her vagina. Have an assistant to help you on your right, and a trolley assistant on your left.

Infiltrate the tissues around the fistula with adrenalin solution, as for a VVF. Use a No. 12 blade to dissect the fistula and separate her vagina from her rectal wall. Extend the incision with curved dissecting scissors.

Close her rectum with continuous ''0' catgut on an atraumatic 5/8 needle. Use similar, but interrupted, sutures for her vaginal

wall. There is no intermediate layer, like the one which you may be able to define between her bladder and her anterior vaginal wall.

POSTOPERATIVELY, (both approaches) care for her as if she had had a large gut repair (9.5). At about 4 weeks, inspect the repair vaginally and with a proctoscope and a sigmoidoscope. Pass a rectal tube (26 to 30 Ch) up to the colostomy. If all is well, close it. If she becomes pregnant again section her.

DIFFICULTIES [s7]WITH FISTULAE (VVFs and RVFs) For vesico-uterine and ureterovaginal fistulae, see Section 18.10.

If she has SEVERE VAGINAL STENOSIS associated with an RVF or VVF, which cannot be reconstituted, she may need a hysterectomy (20.12)[md]which should be subtotal, if you are inexperienced. She and her relatives may be reluctant to accept this. So you may have to wait until she has pain from a haematometra, before she will accept it. She and her husband or a relative must sign for it, before you do it.

If she has a URETHROVAGINAL FISTULA (not uncommon) it is usually an extension from a vesicovaginal fistula, and seldom occurs in isolation, unless it is mistakenly produced surgically.

If it involves the proximal half of her urethra only, and you are experienced, repair it as part of a VVF repair. If she is still incontinent after this, and her fistula has closed, her bladder/urethral junction is incompetent. Refer her for a sling urethroplasty.

If it is more extensive (rare, unless caused by bad surgery, such as a disastrous symphysiotomy), refer her. She is likely to need ureteric diversion.

If you are operating on a JUXTA-URETHRAL VVF or a fistula which involves her urethra, (not advised until you become expert), you will find a Martius graft useful. Repair the first two layers as usual. Leave her vaginal mucosa open for the moment. Make a longitudinal incision in a labium majus and retract the skin edges. Use scissors and dissector to separate a broad-based finger-like pedicle of fibro-fatty tissue from her underlying fascia, taking care to preserve its blood supply. Base it posteriorly and and extend it to about the level of her clitoris: make it long enough to reach her urethra without tension. Before closing her vaginal skin, use scissors to make a tunnel under her labium minor and surrounding skin, through from your present incision to the fistula repair. Stretch the tunnel until it easily accommodates the pedicle. Pass a strong catgut stitch through the tip of the pedicle, draw it into its new bed and suture it over the repair with 2/0 catgut sutures. Finally, cover its tip with her vaginal mucosa. The pedicle will fill dead space, separate her bladder and vaginal mucosa, and improve the repair. If necessary do it on both sides

If she has a ''GISHIRI CUT', it may extend into her bladder or divide her urethra and cause a formidable defect which is almost impossible to close. Traditionally, the Hausas of Nigeria cut the anterior vaginal wall on a variety of indications. Most cuts on non-pregnant women are small and easily repaired.

If SEVERAL ATTEMPTS AT REPAIRING A VVF FAIL, her ureters will have to be diverted into her colon, but only after the most skilled surgeon in the region has done all he can. Diversion of the ureters has an appreciable operative mortality, and urinary infection will shorten her expectation of life.

If she has an unrepaired VVF and succeeds in becoming PREGNANT AGAIN, she is at risk of premature labour. Severe scarring (18.4) may prevent delivery of even a small fetus.

Fig. 18-24 FISTULAE. A, the mechanism of fistula formation. B, various fistulae. C, a vesicovaginal fistula.

1, a vesicovaginal fistula (commonest) is almost always due to pressure from the child's head in a prolonged obstructed labour. 2, a urethrovaginal fistula (not uncommon) is usually an extension from a vesicovaginal fistula, and seldom occurs in isolation, unless it is mistakenly produced surgically. 3, a vesico-uterine fistula (uncommon) is due to damage to the bladder at Caesarean section which is not recognized and repaired (18.10). 4, a rectovaginal fistula (next commonest after a VVF) is usually fairly high in the vagina,, and is due to pressure necrosis of the child's head against the sacral promontary and upper sacrum. (5) An ileovaginal fistula (very rare). Fistulae between the ureters and and the vagina also occur (rare, 18.10), but are not shown here.