Usually, fistulas occur between the 7th and 12th day after obstetric or gynecologic surgery. The diagnosis can be established by filling the bladder with a dilute solution of methylene blue. In a patient with urinary incontinence, the tampon test, where a tampon is inserted into the vagina after filling the bladder with the solution and the patient is ambulated, can lead to the confirmation of diagnosis. Cystoscopy is also of particular help and can clarify the exact anatomic origin. For small fistulas, it may be helpful to attempt to pass a small ureteric catheter through the suspected fistula tract to determine if it enters the vagina.

Dr. Pawan lal
MBBS, MS, DNB (Surgery), MNAMS 
FICS, FIAS, FIMSA, FIAGES, DA
FRCS (Glasg), FACS, FACRSI
 
Professor of Surgery  
Maulana Azad Medical College
(University of Delhi)