Imperforate anus

Imperforate anus – what is it?

Imperforate anus refers to a congenital malformation of the rectum and anus. It is classified as a rare anorectal malformation, occurring in approximately 1 in 3,000 to 1 in 5,000 births, with boys being more commonly affected than girls.

In the case of imperforate anus, there is no regular connection between the rectum and the anus, and as a result affected children fail to pass their first stool after birth. There are different types of imperforate anus. For example, the anus may only be obstructed by a thin membrane, or it may be completely absent.

In addition, there can be an alternative opening of the rectum (medically known as a fistula), which is located elsewhere in the urogenital or rectal area.

What are causes for an imperforate anus?

Imperforate anus develops between the 8th and 12th week of gestation due to an anatomical malformation of the urogenital tract.

The exact cause is still unclear. Hereditary factors seem to play a key role in the development of the condition. Teratogenic substances (i.e. substances that harm the embryo already in the womb) are also considered potential causes.

Other risk factors for the development of imperforate anus of the embryo are obesity, diabetes or smoking during pregnancy.

What are the different types? 

Medically, imperforate anus is classified into different forms based on the location of the existing fistula. This classification describes the fistulas as either "high" or "low," depending on their anatomical location. The prevalence of these forms varies between boys and girls.

• Boys - in males, the recto-urethral fistula is the most common type of an imperforate anus. Besides the missing opening of the anus, there is a defective connection between the rectum and the urethra. As a result, the affected children excrete not only urine but also stool via the urethra.

• Girls - in females, the fistula is often located in the perineum, the area between the vagina and the theoretical position of the anus, lower than in healthy individuals. This area is medically referred to as the perineum, and the condition is known as a low, or rectoperineal, fistula.

What are the typical symptoms of an imperforate anus?

The most significant symptom of an imperforate anus is the absence of the first stool after birth. Affected children may also experience a bloated abdomen and accompanying abdominal pain. The condition is also associated with frequent vomiting and a lack of weight gain.

Moreover, other malformations of the urogenital tract often coincide with an imperforate anus. Therefore, additional symptoms, like problems with urination, may indicate the presence of anatomical abnormalities.

How is an imperforate anus diagnosed?

Usually, an imperforate anus is diagnosed shortly after birth. This may happen during the first physical examination immediately following birth or it may be due to the absence of the child's first bowel movement.

The absence of the anus is usually clearly identifiable allowing a visual diagnosis to be made. In some cases, there may be a dimple of some kind in the normal position of the anus, meaning that the diagnosis can only be confirmed by a digital rectal examination.

If the suspected diagnosis of an imperforate anus is made, it is necessary to examine the affected child for a potential fistula and to determine its exact position. Imaging techniques like an X-ray or ultrasound examination are also used to rule out any other anatomical malformations.

What treatment and surgical methods are available?

The treatment of an imperforate anus depends on the type of the condition and is individually adjusted to the patient.

• In many situations, it is possible to surgically reposition the rectum to its normal anatomical position and to reconstruct the rectum and anus. This operation is known medically as a posterior sagittal anorectalplasty, or pull through surgery, and is usually performed within the first few months of life. In many cases, the existing additional fistula is permeable enough to allow the first bowel movements to pass so that there is no urgent time pressure for surgery.

• In some cases, it may be necessary to create a temporary colostomy immediately after birth, particularly if the fistula is anatomically unfavorable or not adequately patent for stool passage. This colostomy allows the child to be fed normally and gives the medical team more time to plan the next steps of treatment. The colostomy is later repositioned to the normal site once reconstructive surgery of the anus is possible.

• After one of the procedures mentioned above, it may be necessary to regularly dilate the newly constructed anus over several months. This helps prevent the formation of scar tissue that could close the new opening. However, dilation is not required after every anorectal surgery.

What is the life expectancy with an imperforate anus?  

Children who are diagnosed with and treated for an imperforate anus early on generally have a near-normal life expectancy. However, since imperforate anus often occurs in combination with other urogenital malformations or genetic changes, it is difficult to make a generalized prognosis.

In some cases, the affected individual’s quality of life may be impaired by the effects of the surgery. Incontinence can occur after the procedure and this may be a strain for many patients, although this does not affect their life expectancy.

Depending on the severity of the disease, untreated imperforate anus initially leads to constipation and its consequences. By the time the child's diet no longer consists exclusively of breast milk, the stool can no longer be excreted through the fistula and the condition, if left untreated, leads to death.

What are the possible long-term complications of imperforate anus?  

Most patients develop incontinence or recurrent constipation following the treatment for an imperforate anus. This can be particularly distressing for affected individuals, especially as they transition out of childhood.

Therefore, regular follow-up examinations are necessary and treatment with laxatives or a modified diet is recommended.

Which doctors and clinics specialize in imperforate anus?

Imperforate anus is generally diagnosed early after birth by the responsible pediatrician. This usually takes place in hospital and allows further measures to be initiated quickly.

The treatment itself is performed surgically by pediatric surgeons, who can carry out the operation and the initial follow-up examinations during a hospital stay. For ongoing care, which typically continues for life in cases of a treated imperforate anus, initial responsibility lies with outpatient pediatricians and later with general practitioners.

Anyone in need of a doctor would expect the best possible medical care for themselves. Therefore, patients are looking for the most suitable clinic for their needs. Since this is not an objective decision and a respectable doctor would refrain from claiming to be the best, patients must trust the experience of a doctor.

We can help you find an appropriate expert for your condition. All the doctors and clinics listed have undergone extensive review and have been verified by us for their outstanding expertise in the field of imperforate anus. They are looking forward to and are ready to address your questions and treatment requests.