Postoperative MRI of anorectal malformation.

Twenty-five patients who had pull-through rectum (PTR) surgery, some of whom suffered from fecal incontinence, soiling or constipation were studied by magnetic resonance imaging (MRI) postoperatively. MRI demonstrated 14 patients with proper placement of the PTR between the puborectal muscle and external sphincter muscle; four patients with improper placement of the PTR outside the puborectal muscle and external sphincter muscle (one with excess perirectal fat); one patient with disruption of the puborectal muscle and external sphincter muscle; three with hypoplasia of the puborectal muscle and external sphincter muscle; three with asymmetric placement of PTR in the levator ani (one with excess perirectal fat). MRI also depicted seven patients with spine anomalies; five with tethered cord; and 10 with genitourinary tract anomalies. The patients with correct location of PTR all had good fecal continence except three patients (two with soiling and one with constipation) who had tethered cord and ganglion cell dysfunction at the PTR. The patients with improper placement of PTR or poorly developed pelvic muscles all had fecal incontinence. Our study emphasizes that MRI can depict the causes of postoperative incontinence, detect anomalies and help to plan further surgery.