Twenty-two patients with 24 fistulae were examined prospectively with real-
time sonography. Sonographic were compared with those of intravenous urogra
ms and correlated with the findings at examination under anesthesia and at
surgery. Various genital abnormalities not revealed by intravenous urograph
y were demonstrated by sonography preoperatively. These included cervical i
njuries, vesicovaginal fistula showing "flat tire" sign and hourglass defor
mities, and identification of the site, size, and course of fistulae in sev
en (29%) of the cases. However, the demonstration of the fistulae by sonogr
aphy is poor relative to that of examination under anesthesia, in which 21
(87%) of the fistulae were identified. The factors responsible for the diff
iculty in demonstrating the fistulae on sonography, which included size and
multiplicity, are discussed. Sonography is complementary to examination un
der anesthesia in preoperative evaluation of the patients with obstetric fi
stulae in general and in those with previous unsuccessful repairs in partic
ular.