Anorectal Malformation or Imperforate Anus

An imperforate anus or anorectal malformations (ARMs) are birth defects involving anus and rectum. It includes spectrum of anamolies, viz:

  • Imperforate anus: The absence of an anal opening.
  • The anus opening in the wrong place.
  • Recto-vescical fistula: A connection, or fistula, between the intestine and urinary system.
  • Recto-vaginal fistula: A connection joining the intestine and vagina.
  • Cloaca: In females, the intestine ,the urinary system and vagina open in a single opening.

Associated anomalies:

Usually children with ARM have associated other anomalies called the VACTERL association:

  • V – Vertebral anomalies
  • A – Anal atresia
  • C – Cardiovascular anomalies
  • T – Tracheoesophageal fistula
  • E – Esophageal atresia
  • R – Renal (kidney) and/or radial anomalies
  • L – Limb defects

Other entities associated with an imperforate anus are trisomies 18 and 21, the cat-eye syndrome


Diagnosis is usually made at birth as the defect is evident. Child fails to pass meconium (first stool) or passes it from the place other than the normal place.

  • Careful clinical examination
  • Invertogram/Left lateral cross table X ray: To see the level of defect
  • Cardiac echocardiogram will be needed to rule out heart anomalies.
  • Renal ultrasound will be necessary to identify any urinary anomalies.
  • Spine MRI will be required to rule out a tethered cord or abnormal attachment of the spine cord to the vertebrae


Depends upon the type of anomaly. If small opening/ fistula is present at skin, urethra or vagina, a newborn will pass meconium. If there is no such opening, then the priorty is to create the passage for passing stool-stoma. Thus child will require 3 operations to correct the anorectal malformation, as determined by the anatomy: The first is to create a stoma, the second is to place the rectum through the center of the anal sphincter and the third to close the stoma. Some children will only need one operation, to place the rectum through the center of the anal sphincter.