Describe vesicovaginal fistula — its aetiology, clinical features and management.

Definition

A vesicovaginal fistula (VVF) is an abnormal communication between the urinary bladder and the vagina, resulting in continuous, involuntary escape of urine through the vagina.

Causes

• Obstetric (commonest in developing countries) — pressure necrosis from prolonged/obstructed labour, and instrumental/operative delivery injury.
• Gynaecological/surgical — injury during hysterectomy or pelvic surgery.
• Radiation for pelvic malignancy, and advanced cervical/vaginal carcinoma.

Classification

VVF is classified by site (juxta-urethral, mid-vaginal, juxta-cervical/vault), by size, and by complexity (simple vs complex — large, scarred, radiation-induced, or involving the ureter/urethra), which together determine the route and difficulty of repair.

Clinical Features and Diagnosis

Continuous dribbling of urine per vaginum with a constantly wet, excoriated vulva. Diagnosis is by speculum examination, the dye (methylene-blue/three-swab) test to locate and distinguish it from a ureterovaginal fistula, and cystoscopy with imaging (IVU) to assess the ureters.

Management

• Small, fresh fistulae — continuous bladder catheter drainage may allow spontaneous healing.
• Surgical repair — usually after about 3 months (once inflammation settles), by the vaginal or abdominal route, with interposition of healthy tissue.

Investigations (detail)

The three-swab (dye) test — methylene blue is instilled into the bladder and three swabs are placed in the vagina; staining of the upper swab suggests a ureterovaginal and of the lower/middle swab a vesicovaginal fistula. Cystoscopy, examination under anaesthesia and intravenous urography define the site, size and ureteric relations.

Principles of Repair

Repair is by the vaginal or abdominal route with wide mobilisation and tension-free, layered closure and, where needed, interposition of healthy tissue (e.g. Martius graft); a catheter is left for continuous drainage afterwards.

A Note on WHY VVF Is a Disease of Obstructed Labour and Poverty

A useful point is understanding why the vesicovaginal fistula is, in India and much of the developing world, an obstetric rather than a surgical disease — and why it is a tragedy of access. In prolonged obstructed labour, the fetal head is impacted against the pelvis for hours or days, and the soft tissues of the bladder base, urethra and anterior vaginal wall are crushed between the head and the pubic bone. The pressure occludes their blood supply, so the tissue becomes ischaemic, necroses and sloughs — typically several days after delivery, when the woman (who has usually lost her baby) suddenly begins to leak urine continuously. The consequences go far beyond the physical: the woman is constantly wet and offensive, and is frequently abandoned by her husband, ostracised by her community and reduced to destitution — so that VVF is as much a social catastrophe as a medical one. Two conclusions follow. First, that in the developed world the same fistula arises instead from surgery (hysterectomy) or radiotherapy. Second, and far more important, that obstetric VVF is entirely preventable — by the partogram, by timely caesarean section, and by access to emergency obstetric care; its continued existence is a direct indictment of maternal health services.

Continuous painless leak of urine is diagnostic.

• VVF = an abnormal communication between bladder and vagina → continuous, painless leakage of urine per vaginam.
• In India the commonest cause is obstructed labour (pressure necrosis of the bladder base against the pubis); in the West it is surgery (hysterectomy) or radiotherapy.
• Diagnosis: three-swab (dye) test, methylene blue instillation, cystoscopy and IVU (to exclude a coexisting ureteric fistula).
• Repair after ~3 months (allowing the inflammation to settle) — by the vaginal (Latzko) or abdominal route; continuous bladder drainage afterwards is essential.
• It is entirely preventable — by the partogram, timely caesarean section and access to emergency obstetric care; the social consequences (abandonment, ostracism) are devastating.