The overall incidence of vesicovaginal fistula is unknown but was reported to be 2.11 per 100 births in Nigeria 1.
The tract is lined by squamous epithelium at the vaginal end and transitional epithelium at the bladder end, often with focal ulcerations and fibrosis.
There are a number of causes including
- prolonged obstructed labour (most common in developing countries)
- surgery, e.g. hysterectomy (most common in developed countries)
- pelvic malignancy (e.g. bladder carcinoma, endometrial carcinoma)
- uterine rupture
Other risk factors include trauma, pelvic inflammatory disease and diabetes 3.
A fluoroscopic cystogram is a commonly-used method for evaluating this type of fistula. Contrast is injected into the bladder through a Foley catheter and the fistulous tract is outlined. A number of oblique and lateral projections are needed to determine the location.
Gas-fluid levels are seen within the vagina which disappear with 3-4 micturitions, whereas gas bubbles are seen within the bladder for up to one week.
The fistula may be seen as a hypodense area with excretion of contrast into the vagina on delayed CECT images. The tract may be visible if a CT cystogram is performed.
- T1: tract is centrally hypointense (fluid)
- T2: tract is hyperintense with gas bubbles seen as low signal intensities
- T1 C+ (Gd): peripheral enhancement on contrast
- 1. Ijaiya MA, Rahman AG, Aboyeji AP et-al. Vesicovaginal fistula: a review of nigerian experience. West Afr J Med. 29 (5): 293-8. - Pubmed citation
- 2. Hricak H. Diagnostic Imaging, Gynecology. Amirsys Incorporated. (2007) ISBN:1416033386. Read it at Google Books - Find it at Amazon
- 3. Yu NC, Raman SS, Patel M et-al. Fistulas of the genitourinary tract: a radiologic review. Radiographics. 2004;24 (5): 1331-52. Radiographics (full text) - doi:10.1148/rg.245035219 - Pubmed citation