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Fecal Incontinence and Anorectal Malformations

Fecal Incontinence and Anorectal Malformations

Bowel control depends on three main factors:

  • Sensation (feeling)
  • Movement of the colon (called motility)
  • The muscles or sphincter around the anus 

Having an anorectal malformation likely means that one or all of these factors did not form the right way.  This can range from a minor lack of forming to not forming at all.

Sensation within the Rectum

Children born with anorectal malformations often lack some degree of sensation.  This means they are not able to feel stool or gas pass through their rectum. The child may have no feeling at all or may be able to feel solid stool, but not loose stool.  Many times the child may soil their pants without knowing it. They may also get used to the smell of their stool.

Motility of the Colon

Rectosigmoid colon image.


The rectosigmoid colon is the part of the bowel where stool collects and is “stored” between bowel movements. In most cases, the rectosigmoid is quiet for about 24 hours. This is the time needed to collect the stool. Then a big contraction allows it to fully empty the stool. Then it is quiet again.

If the rectosigmoid is slow, the stool stays in the rectum. Constipation occurs and the child may suffer from soiling. This is caused by stool leaking around the hard stool. On the other hand, if a child has no rectosigmoid (due to surgery), they will pass stool all the time.

What Is a Voluntary Sphincter and Why Is It Important?

The voluntary sphincter is a group of muscles that surround the rectum and anus. These muscles are vital for bowel control.

  • In children with anorectal malformations, these muscles are less developed and are not able to keep the stool from leaking out.
  • The more complex the anorectal malformation, the less developed the sphincter muscles are.
  • It is vital for the placement of the rectum to be exactly within the limits of the sphincter at the time of the child's Pull-Through / PSARP surgery.

Are There Things that Help Predict Good Bowel Control?

After the main repair and the colostomy closure, the surgeon can predict if the child may have good bowel control.   

Indicators of Good Bowel Control  

  • Normal sacrum (lowest part of the spine / backbone) 
  • Well-formed buttocks muscles 
  • Some types of anorectal malformations. This includes rectal atresia, vestibular fistula, imperforate anus without fistula, cloaca with less than 3cm common channel, perineal fistula.

Indicators of Poor Bowel Control 

  • Abnormal sacrum (lowest  part of the spine / backbone) 
  • Flat buttocks (poor muscles) 
  • The presence of a tethered spinal cord (spinal cord abnormally attached to the spine) 
  • Some types of anorectal malformations. This includes rectobladderneck fistula, cloaca with greater than 3cm common channel, complex malformations. 

It is vital to prevent constipation and promote regular bowel movements in the months and years between the final surgery and the time of potty training (most often around 3 years of age).

What Determines How Well My Child Is Doing?

Children with good bowel control will have: 

  • Good bowel movement patterns. They will have one to two bowel movements per day with no soiling in between 
  • Signs of feeling when passing stool (pushing, making faces) 
  • Urinary control 

Children with good bowel control may have soiling if they: 

  • Have a viral illness  
  • Take medicine that causes diarrhea (e.g., antibiotics) 
  • Become constipated

When the cause of the diarrhea has resolved (a viral illness or medicine), they should get their bowel control back. 

Children with poor bowel control may have:

  • Soil and pass stool all the time
  • No signs of feeling when passing stool (no pushing, making faces or saying they have to go)
  • No urinary control or dribbling of urine

Parents must be informed about their child's chances for bowel control to avoid needless frustration later. It is vital to figure out the level of bowel control the child is able to have as early as possible so parents know what to expect. Since there are a wide range of defects, we should expect a wide range of results.

For Anorectal Defects Linked to Poor Outcomes

If the child's type of defect is linked with a poor outcome, they will likely have to start a bowel management program with a daily enema to stay clean of stool.

For these children, this program with a daily enema should be started when the child is 3 or 4 years old, or when their peers are out of diapers.

We always give each child the chance to prove their potential for bowel control. Children who have poor bowel control now may become more aware of their bodies as they get older. When this happens, we let them try a program that does not have of a daily enema.

Last Updated 07/2018

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