The pelvis of fetuses in the exstrophy complex.

Abstract

By using a three-dimensional computed tomography (CT) scanner, we compared the anatomic features of the pelvis of three fetuses of same gestational age, one with a normal pelvis representing the reference model, one with classic bladder exstrophy, and one with cloacal exstrophy. The tomography slices were selected at the same levels for each case. Three angles expressing external opening of the pelvis were defined. Comparing normal and abnormal pelvises allowed definition of three criteria for the correction of the malformation: (a) the sum of the differential angles gives the amplitude of the correction needed; (b) a supraacetabular osteotomy appears to allow best closure of the pelvic ring; (c) only three slices of a CT scan are needed, which cannot be harmful, especially for neonates. Therefore, we believe that a CT scan of the pelvis should be performed whenever an osteotomy is planned in the surgical reconstruction of bladder and cloacal exstrophy.