Anorectal Malformation

Etiology:
— Congenital
— Is high if rectal pouch is above levator sling
— Is low if rectal pouch is below levator sling
Imaging AXR prone cross table lateral with child over bolster:
— Most helpful in patients without clinical evidence of fistula
— Can outline rectal pouch and evaluate length of anorectal malformation,
Imaging Fluoroscopy:
— Rectourethral fistula demonstrated by colostomy anterograde injection
— Enterolith – intraluminal meconium may calcify when mixed with urine from rectourethral fistula
Imaging MRI: Useful in evaluating levator sling and to look for post operative complications
DDX:
Complications:
— Rectoperinal fistula – 95% of anorectal malformation have recto-perineal fistula, in male 50% goes to urethra and 30% goes to seminal vesicle, in female 40% goes to urethra and 30% goes to vestibule and 25% goes to vagina
— Often have continence issues post op
Treatment:
Clinical: Have VACTERL syndrome

Radiology Cases of Anorectal Malformation

AXR of anorectal malformation — AXR (above) shows multiple dilated loops of bowel within the abdomen that are progressively more dilated as they near the rectum. Prone cross-table lateral radiograph of the abdomen obtained after 10 minutes in the prone position (below) with a radio-opaque BB on the anus shows a short distance between the anus and the gas in the rectum.

AXR of cloacal exstrophy — AXR AP shows diastasis of the symphysis pubis and multiple spinal segmentation defects while the AXR lateral shows a small amount of bowel herniated anterior to the abdomen and inferior to the umbilicus along with a large skin covered spinal dysraphism posteriorly and a radioopaque marker being held in place over where the anus should be.

AXR of cloacal exstrophy — AXR shows diastasis of the symphysis pubis, multiple loops of bowel outside the contour of the abdomen inferiorly, and multiple segmentation anomalies in the lower lumbar spine and sacrum.

Radiology Cases of Low Anorectal Malformation

US of low anorectal malformation — CXR AP (left) shows a hemivertebra at L1 causing spinal curvature convex left. Transverse US of the pelvis (above right) shows in the midline anteriorly an anechoic fluid-filled bladder with a round echogenic stool-filled rectum posterior to it while a transverse US of the perineum (below right) shows a very short distance between the calipers superiorly on the skin and inferiorly on the anterior wall of the rectum.

Radiology Cases of High Anorectal Malformation

AXR of anorectal malformation — AXR shows a distal bowel obstruction with gas down to the rectum. On physical exam the anus was absent.

Clinical Cases of Anorectal Malformation

Clinical image of anorectal malformation / imperforate anus — Clinical image shows absence of the anal orifice. There is a good buttock cleft. There were no perineal or scrotal raphe fistula seen.

Clinical image of anorectal malformation — Clinical image shows meconium exiting the urethral meatus.

Clinical image of anorectal malformation — Clinical image shows electrical stimulation of the perineal tissues causing strong muscular contractions suggesting excellent anal sphincters for later reconstruction.

Clinical image of anorectal malformation — Clinical image shows normal appearing external genitalia, but no anus. Examination of the vaginal introitus reveals a rectal fistula to the posterior vaginal fourchette in the midline, located just inferior to the vagina.

Surgery Cases of Anorectal Malformation

Surgical image of anorectal malformation — Surgical image shows the rectum opened posteriorly through a posterior sagittal incision. A small catheter (in the center) is shown coursing through a rectourethral fistula.