Sonographic detection and localization of fistulas in fetuses with imperforate anus: Case reports.

Imperforate anus (IA) requires urgent treatment after birth, which is dependent on the type of IA, and is also frequently associated with other congenital abnormalities. Most patients with IA have an accompanying fistula, whose location is strongly associated with the type of IA. The fistula location can be a key factor in defining appropriate treatment, especially in neonates presenting with severe associated abnormalities. Herein, we report three cases of IA in which fistulas were detected and localized prenatally. Examination of the fetal pelvis through the sagittal or coronal view, using high-frequency transducers, revealed the location of the fistulas. In particular, the sagittal view obtained using the fetal infracoccygeal or perineal approach allowed us to determine the precise anatomy of the fistulas. Neonatal assessment confirmed the fistula locations. We recommend using the sagittal view obtained using the fetal infracoccygeal or perineal approach with high-frequency transducers to assess fistulas in fetuses with IA.