- Acquired: This is the commonest type. The causes of this type are following:
- Obstetric Trauma in delayed and obstructive labour, instrumental delivery or incomplete healing of the repair for complete perineal tear caused by difficult labour.
- Operative trauma
- Pelvic Abscess
- Cancerous fistula
- Forgotten pessary
- Congenital Causes: This may very rarely lie in the form of small opening or a big opening. There may or may not be anal opening in its normal position. Rarely the anal opening may be present at the posterior part of the vestibule of the vagina without any anal opening in the perineum. This is called vestibular anus.
Sites: This may be on:
- a) The lower third of the vagina- commonest;
- b) Middle third or
- c) Upper third of the vagina.
Symptoms: In small fistula, there may not be any symptom but leakage of gas; faecal vaginal discharge occurs only when there is diarhhoea. In big fistula, incontinence of stool per vagina is an annoying symptom.
Signs: It is easy to detect the moderate to big size fistula by exposing the posterior vaginal wall by a vaginal speculum as well as by a rectal examination. In these fistulae, much of scarring at the fistula margin or even vaginal atresia may be also present. In case of very small fistula, examination under anesthesia is done; a probe is pushed through the fistula from the vaginal opening and the tip of the probe can be felt by the rectal examination.
Treatment/Prevention: This is most important by providing good obstetric care and respect to bowel during gynecological operations.
Curative: Surgical local repair of the rectovaginal fistula is the treatment of choice for non malignant cases. The methods of the treatment may be as follows:
- V.F. low down in the vagina: The fistulous tract is adequately exposed by converting the fistula into complete perineal tear by incising the scarred perineum and external anal sphincter below the fistula.
- V.F. in the middle or upper part of the vagina: Repair by dissection and mobilization of the bowel by the flap splitting method is performed.
Malignant R.V.F.: Colostomy is performed as a palliative measure.