Utility of spinal MRI in children with anorectal malformation

Background: The association between spinal cord anomalies and imperforate anus is well recognized. Until now, the incidence of tethered cord has been assumed to be higher in patients with high-type imperforate anus. However, recent reports suggest that tethered cord is as common in patients with a low lesion as in those with a high lesion. Objective: To review the incidence of spinal cord anomalies in those with a low lesion and those with a high (including intermediate) anorectal malformation (ARM), and to determine the best diagnostic imaging strategy. Materials and methods: A group of 50 consecutive patients with postoperative ARM and in whom spinal MRI had been performed were identified retrospectively. We reviewed and compared the following factors between those with a high lesion and those with a low lesion: (1) clinical symptoms, (2) spinal cord anomalies, and (3) vertebral anomalies. Results: The incidence of spinal cord anomalies was no different between those with a high lesion and those with a low lesion, and spinal cord anomalies were present regardless of the presence of vertebral anomalies or symptoms. Conclusion: Owing to the high incidence of spinal cord anomalies in patients with imperforate anus, MRI is the best imaging tool for detecting such anomalies regardless of the level of the lesion.