Evaluation

Dye test
Methylene blue dye is introduced into urinary bladder by a catheter a little wait is done for dye to leak through the fistula.

Three swab test
Methylene blue dye is introduced into urinary bladder by a catheter then three swabs are introduced into the vagina, one at the vault, another at the middle aspect and the third at the introitus. The patient is instructed to take a walk for 3 to 5 minutes after which the swabs are taken out for inspection.