Abnormal communication between urinary system and skin or internal hollow viscus. Persistence of skin fistula implies distal obstruction or chronic infection e.g. TB or foreign body like store or non-absorbable ligature.

Types

• Congenital:

- ectopic vesicae, patent urachus and urachal cyst
- anorectal malformations

• Traumatic:

- penetrating wounds

- Iatrogenic (bladder, prostate, urethral surgery)

• Vesico-vagino-fistula [see 18.8. abscesses and fistulae].