What is a genital fistula?
A genital (genitourinary or genitoanal) fistula is an abnormal opening between the genital tract and the urinary tract or bowel. The two exam favourites are the vesicovaginal fistula (VVF) — bladder to vagina, the commonest — and the rectovaginal fistula (RVF) — rectum to vagina. Others include ureterovaginal, urethrovaginal and vesicouterine fistulae.
The hallmark of VVF is continuous, involuntary leakage of urine through the vagina — day and night, unrelated to effort or urgency. An RVF causes passage of flatus or faeces per vaginam, foul-smelling discharge and dyspareunia.
What causes vesicovaginal and rectovaginal fistulae?
| Setting / type | VVF | RVF |
|---|---|---|
| Low-resource countries | Prolonged obstructed labour → pressure necrosis of the bladder base trapped between fetal head and pubis | Obstructed labour; third- and fourth-degree perineal tears |
| High-resource countries | Gynaecological surgery — bladder injury at hysterectomy is the commonest cause in North America | Obstetric injury is still the commonest cause of traumatic RVF and probably of all RVFs |
| Other acquired causes | Malignancy (cervical cancer), pelvic radiation, other pelvic or urological surgery, instrumentation, infection, sexual trauma, vaginal foreign bodies | Crohn's disease, radiation, diverticular disease, rectal or gynaecological cancer, pelvic surgery |
| Congenital | Very rare, with other urogenital malformations | — |
In obstructed labour the presenting part continually compresses the birth canal, bladder base, urethra or sometimes the rectum, causing ischaemia and necrosis. The dead tissue sloughs, so leakage usually appears 1–2 weeks after the delivery. After surgery, a VVF classically presents with leakage 7–12 days post-operatively, reflecting tissue necrosis or a strangulating suture.
How big is the problem of obstetric fistula?
WHO estimates that 50,000–100,000 women develop obstetric fistula every year, and more than 2 million young women live with untreated fistula in Asia and sub-Saharan Africa. Women live with constant incontinence, shame and social isolation, skin infections and kidney disease — and untreated fistula can be fatal.
- Poverty and malnutrition
- Early marriage and early first pregnancy
- Low literacy
- Lack of skilled birth attendance and of emergency obstetric care, including timely caesarean section
- Harmful traditional practices
Indian community data show the same pattern. A study in a rural south-eastern Indian community found obstetric fistula more common among women with poor education, low socioeconomic status, fewer antenatal visits, prolonged labour and delays in reaching emergency obstetric care — including repeated moves between home and delivery points. An earlier analysis of national household (DLHS-3) data likewise tied fistula to prolonged obstructed labour without timely help and highlighted auxiliary nurse midwives in early detection and referral of cephalopelvic disproportion, malpresentation and obstructed labour.
How do the three-swab and dye tests localise a fistula?
Diagnosis starts with the history (recent surgery, obstructed labour, radiation) and a careful speculum examination, which may show the fistula or pooling of urine. Dye tests then confirm that the fluid is urine and show where it comes from.
| Test | How it is done | Interpretation |
|---|---|---|
| Tampon (methylene blue) dye test | Tampon or gauze placed in the vagina first; bladder back-filled with dilute methylene blue (200–300 mL); patient walks | Blue at the upper (apical) end → VVF. Blue only on the distal tampon → spillage or ordinary incontinence |
| Double-dye test | Oral phenazopyridine (turns urine orange) before the visit; tampon in; then bladder filled with methylene blue | Orange only → ureterovaginal fistula. Orange + blue → VVF (a coexisting ureteric fistula is not excluded) |
| Three-swab test | Three separate cotton swabs placed one above the other in the upper, middle and lower vagina; bladder filled with methylene blue; swabs removed after about 10 minutes | Swabs wet with urine but not blue → ureterovaginal fistula. All three blue → high (pinhole) VVF. Lower two blue, upper one dry → mid-vaginal VVF |
| Vaginal fluid creatinine | Fluid sent for creatinine | A high creatinine level confirms the fluid is urine |
| Investigation | Purpose |
|---|---|
| Cystoscopy | Number, site and size of bladder openings; relation to ureteric orifices and trigone; residual bladder injury |
| Retrograde pyelography | Ureteric integrity |
| CT urogram (multiphasic) | Recommended before repair to detect a concomitant ureteric fistula or obstruction (IVU can miss a leak close to the trigone) |
| Transvaginal ultrasound, MRI | Size and course of the tract; MRI or endoanal ultrasound for RVF and complex disease |
| Examination under anaesthesia | Early post-injury assessment and dye testing |
When should a vesicovaginal fistula be repaired?
A simple VVF is single, small (< 0.5 cm), in a non-irradiated patient with no malignancy. Small, early-detected, non-malignant fistulae may close spontaneously with continuous bladder drainage — a Foley catheter for 2–8 weeks, with anticholinergics for bladder spasm.
- If tissues are inflamed, oedematous or necrotic, surgery is postponed for up to 2–3 months to let tissue health recover.
- If there is no inflammation and the tissue looks healthy, repair need not be delayed.
- After a failed repair, wait about 2–3 months before trying again.
- The first operation offers the best chance of cure — it should be done by an experienced surgeon at the right time.
Which surgical approach is used, and what is a Martius flap?
| Approach | When used | Notes |
|---|---|---|
| Transvaginal | Preferred when feasible — most obstetric and low fistulae | Less invasive, allows earlier repair; success about 91% in non-irradiated patients |
| Transabdominal (transvesical, extravesical, laparoscopic or robotic) | High fistulae at the vault, need for ureteric reimplantation, associated abdominal pathology | Success about 97% in non-irradiated patients |
| Interposition flap | Complex fistulae — after radiation, recurrent or large defects | Brings well-vascularised tissue between bladder and vaginal repairs |
Overall reported success of VVF repair ranges from 70% to 100%. Of the tissue interposition flaps, the Martius flap (labial fibrofatty tissue, used transvaginally) is the most frequently used autologous flap; the omental flap is also widely used, mainly with abdominal repairs. Synthetic options include fibrin glue.
- Post-operatively the bladder is drained continuously — catheter for 2–3 weeks — often with a cystogram before removal.
- Main complication: recurrence of the fistula.
- Other complications: urgency and frequency early; stress incontinence later, especially after obstetric fistulae that damaged the urethral sphincter.
How is a rectovaginal fistula classified and treated?
| Type | Location | Usual approach |
|---|---|---|
| Low RVF | Lower third of the rectum and lower half of the vagina — close to the anus (often obstetric) | Perineal (transperineal) repair; sphincteroplasty with fistulectomy if the sphincter is damaged; endorectal advancement flap for simple fistulae |
| High RVF | Between the middle third of the rectum and the posterior vaginal fornix | Abdominal approach; resection of the diseased rectal segment in radiation, cancer or diverticular disease |
- Treat the cause — control Crohn's disease, diverticulitis or cancer before or alongside repair.
- A draining seton controls acute or recurrent infection and prepares tissue for repair.
- Fibrin glue and plugs are simple but have low success rates.
- Gracilis muscle interposition for complex or recurrent fistulae; a diverting stoma for high-risk patients or severe disease.
- Complications: faecal incontinence, perineal irritation, abscess and recurrence.
How can obstetric fistula be prevented?
WHO states that obstetric fistula is preventable — it can largely be avoided by timely, quality obstetric care. Prevention targets the chain from early pregnancy to unrelieved obstructed labour:
- Delaying the age at first pregnancy and ending harmful traditional practices.
- Family planning, adequate antenatal visits and skilled attendance at every birth.
- Timely access to emergency obstetric care, including caesarean section, so obstructed labour is relieved early.
- Early recognition of leakage after a difficult labour or pelvic surgery — small, early fistulae may close with continuous catheter drainage for 2–8 weeks.
- Care to avoid bladder and ureteric injury at hysterectomy and other pelvic surgery — the leading cause in high-resource settings.
- Affordable fistula repair services and social reintegration for women already affected.