Imaging of anorectal malformations in the neonatal period

The classification of anorectal malformations (ARM) as high or low is based on clinical and anatomical characteristics. It has an impact on the surgical management but also on the functional prognosis. In the absence of consensus, our goal was to determine the value of imaging in the neonatal period for diagnosis and management of infants with ARM. Retrospective study of 43 infants imaged over a 9 year period. The different imaging studies (abdominal and pelvic ultrasound, radiographs, percutaneous opacifications and fistulograms) performed for each infant were collected and analyzed then correlated to clinical and surgical findings. Clinical evaluation could classify 30 ARM as low and 4 ARM as high while 9 ARM without fistula remained indeterminate. Imaging findings were mixed: on ultrasound, the rectal cul-de-sac to perineum distance did not appear to be determinant, contrary to published data. Pelvimetry showed limitations, irrespective of the technique. Morphological evaluation provided the following data: presence of fistula, sphincter anatomy, rectal cul-de-sac to perineum distance. Classification relies on clinical evaluation in most cases. Opacification techniques and ultrasound remain useful in some cases. MRI could become the preferred imaging modality.