MRI findings in patients with defecatory dysfunction after surgical correction of anorectal malformation

Postoperative anorectal malformation patients frequently have defecatory dysfunction. MRI may be useful in the management of these patients.

To analyze static and dynamic MRI findings in patients with defecatory dysfunction after correction of anorectal malformation (ARM), and compare differences between patients with constipation and fecal incontinence.

Pelvic MRI studies of 20 constipated and 32 incontinent postoperative ARM patients were analyzed retrospectively to determine the location and morphology of the neorectum, presence of peritoneal fat herniation, presence of scarring, development of the striated muscle complex (SMC) and any other abnormalities. The two groups were then compared using χ(2)-test. Eighteen patients also underwent MRI defecography to evaluate pelvic floor function and abnormalities are reported.

The children with incontinence were more likely to have abnormal location of the neorectum (P = 0.031), increased anorectal angle (ARA) (P = 0.031) and peritoneal fat herniation (P = 0.032), and less likely to have dilation of the neorectum (P = 0.027), than the children with constipation. There were no significant differences between the two groups in incidence of focal stenosis of the neorectum (P = 0.797), presence of extensive scarring (P = 0.591) and developmental agenesis of the SMC (P > 0.05). MRI defecography showed 6 anterior rectoceles, 6 cystoceles and 18 pelvic floor descents.

MRI is a helpful imaging modality in postoperative ARM patients with defecatory dysfunction, and it shows distinct differences between the children with constipation and incontinence and provides individualized information to guide further treatment.