Anorectal malformation (imperforate anus or ARM)

What are anorectal malformations?

Anorectal malformations occur when a child’s rectum (last section of the large intestine), anus (opening where stool comes out) or both don’t form correctly. A child may be born with an opening that’s missing, too small and/or in the wrong place. This congenital condition happens while a baby is developing in the womb and is present at birth.

Anorectal malformations can affect a child’s ability to poop. If stool backs up too much, it can cause a potentially life-threatening blockage. Many children with anorectal malformations may have other birth defects as well.

What causes anorectal malformations?

About 1 in every 5,000 newborns has an anorectal malformation. This congenital condition occurs for no apparent reason while a baby develops in the womb. There’s nothing a pregnant woman can do to prevent it. Rarely, the condition runs in families, which suggests that gene changes may play a role.

What other conditions may occur with anorectal malformations?

About half of children born with an anorectal malformation also have other problems. This is because these structures are developing all around the same time during the pregnancy.

VACTERL – Children diagnosed with VACTERL often have 3 or more other problems of the structures listed below:

• Vertebral – bones that make up the spine and sacrum (tailbone)

• Anus – anorectal malformation

• Cardiac – heart

• Trachea – windpipe

• Esophagus – tube that joins the mouth to the stomach

• Renal – kidneys or other parts of the urinary tract

• Limbs – arms and legs

Tethered cord – This occurs when the spinal cord is attached to tissue around the spine, most often at the lowest part of the spinal cord. It keeps a child from moving freely when they bend and move.

Sacrum and Spine anomalies – Some children are missing part or all of the sacrum (the large group of bones at the lower spine).

Cardiac defect – A congenital heart defect is a problem with the structure of the heart. It is the most common type of defect found with an anorectal malformation. The type and how bad the defect is, will be different for each child.

Esophageal Atresia / Tracheoesophageal Fistula – Esophageal atresia is a defect that occurs when the upper esophagus does not join with the lower esophagus and stomach. A tracheoesophageal fistula (TEF) is present when the esophagus joins with the trachea (windpipe).

Kidneys and Urinary tract – The kidneys may not be formed or work normally. Pee (urine) may back up from the bladder towards the kidneys, or the bladder may be small and not drain normally.

Gynecologic anomalies – Girls born with an anorectal malformation may not have normal development of the inside female structures, also called gynecologic or reproductive structures (uterus, fallopian tubes, and vagina).

What are the different types of anorectal malformations

The various types of anorectal malformations affect boys and girls differently.

Anorectal malformations that affect boys and girls

These malformations can occur in boys or girls:

• Rectoperineal fistula: The rectum opens in a hole on the perineum (the skin between the anus and genitals). The opening may look like an anus, but it’s not in the normal place for an anal opening.

• Anal atresia, anal stenosis, rectal atresia and rectal stenosis: Atresia means the structures are missing or didn’t form correctly so that it is a blind end. Stenosis means the structures are too narrow or only open partially. As a result, poop can’t pass through as it should.

• Cloacal exstrophy: The intestines and other abdominal (belly) organs are located outside the body. Certain parts of the reproductive, urinary and digestive systems may not form properly.

Anorectal malformations that affect only boys

These malformations only happen in boys:

• Rectobulbar urethral fistula: The anus is missing. The rectum connects to the lower (bulbar) part of the urethra (the tube that carries pee out of the body).

• Rectoprostatic urethral fistula: The anus is missing. The rectum connects to the upper part of the urethra, closer to the bladder (where pee is stored).

• Recto-bladder neck fistula: The anus is missing. The rectum connects to the bottom of the bladder, where the urethra starts.

Anorectal malformations that affect only girls

These malformations only happen in girls:

• Rectovestibular fistula: The anus is missing. The rectum opens behind the vagina.

• Cloacal malformation: The anus is missing. The urethra, vagina and rectum join into a single channel (tunnel) instead of three separate channels.

How are anorectal malformations diagnosed?

Doctors often detect an anorectal malformation while performing a physical exam on your baby shortly after birth. Physical exam findings might include:

• Lack of an anal opening

• An opening that is too tight or narrow or in the wrong location, such as too close to the vagina or scrotum

• Not passing bowel movements normally

• Stool coming out of the urethra, vagina, base of the penis or scrotum

• Swollen abdomen

Sometimes, anorectal malformations are diagnosed in older children when the malformation is not as obvious on physical exam. Often times these children will have issues with pooping.

How are anorectal malformations treated?

Nearly all anorectal malformations require a reconstructive surgery called anorectoplasty.

Your child’s treatment depends on the type of anorectal malformation and severity. Some children need a single surgery without an ostomy (opening in the belly for poop to leave the body). Surgeries to repair complex malformations require an ostomy and take place in stages.

Our Colorectal and Pelvic Center brings together all the specialists your child needs, including pediatric surgeons, urologists and gastroenterologists. Girls may also see a gynecologist.

You can entrust your child’s care to us. We’re a designated Level I Children’s Surgery Center by the American College of Surgeons Children’s Surgery Verification™ Quality Improvement Program. This verification is the highest level of recognition for pediatric hospitals that perform complex surgeries on newborns and children.

We offer:

Ostomy

A doctor diverts part of your child’s large intestine and connects it to a surgically created opening in the belly (stoma). Stool exits through this opening into a bag outside the belly. A second small surgical opening (mucous fistula) allows the closed end of the rectum to drain fluid or mucous into the bag.

Our care team will teach you how to care for your child while they have the ostomy. Your child may undergo further surgeries in the future to reconnect the digestive tract and close the stoma.

Posterior sagittal anorectoplasty (PSARP)

In a posterior sagittal anorectoplasty (PSARP), a surgeon repositions the rectum to create an anal opening at the correct location. This surgery is typically performed only on the bottom. Sometimes additional surgery is done through the belly. Our surgeons have the expertise to perform that surgery laparoscopically, so the surgery takes place through small, keyhole-sized incisions. With this approach, your child has a faster, less painful recovery. If your child has an ostomy, it will stay in place after the PSARP until the digestive tract heals.

• Children’s Health Colorectal and Pelvic Center: Patient Education Resources

• ONE in 5000 Foundation: Resources for the imperforate anus/anorectal malformation community

• The Rare and Resilient - ONE in 5000 Podcast: Podcast produced by the ONE in 5000 Foundation

• Youth Rally: Camp experience for youth living with conditions of the bowel and/or bladder system

• Pull-Thru Network: Support for families of people born with an ARM, colon disease and associated issues

• United Ostomy Associations of America, Inc.: Support, empowerment and advocacy for people who have had ostomy and/or continent diversion surgery

• Imperforate Anus USA Support Group: Private Facebook group to support families of people who have imperforate anus