How Common is Imperforate Anus?

Imperforate anus affects about 1 in 5,000 new births in the U.S.

What are signs and symptoms of Imperforate Anus?

Signs and symptoms of Imperforate Anus include: - Anal opening missing or presence of a small pit - Abnormal opening before the anal controlling muscle - Fistula leading to urinary tract - Signs of meconium in male newborns' urine - In females, single, three, or two openings in the genital area along with absent anus - Flat bottom or perineum and missing buttocks fold

How do you get Imperforate Anus?

The exact cause of anorectal malformations, including imperforate anus, is not known. It is believed to be due to a mix of different factors, including genetic conditions like trisomy 13, 18, or 21, as well as certain syndromes like Currarino syndrome, Townes-Brock syndrome, and Pallister-Hall syndrome. Other risk factors include the father smoking and the mother being overweight, obese, or having diabetes.

What else can Imperforate Anus be?

The doctor needs to rule out the following conditions when diagnosing Imperforate Anus: 1. Abnormalities in the genitourinary system (reproductive and urinary organs) 2. Abnormalities in the musculoskeletal system (muscles and bones) 3. Issues with the spine and spinal cord 4. Vertebral anomalies 5. Associated heart defects 6. Tethered spinal cord syndrome

What kinds of test are needed for Imperforate Anus?

The types of tests that are needed for Imperforate Anus (anorectal malformation) include: 1. Ultrasound imaging: This includes an ultrasound of the abdomen and pelvis to check for abnormalities in the digestive and urinary systems, and another ultrasound specifically for the perineum to estimate the distance between the rectal pouch and the perineum. 2. Lateral radiograph: This type of X-ray is performed while the patient is lying on their stomach to determine the location of any air in the lower part of the bowel. 3. X-ray of the entire spine: This is done to identify any vertebral anomalies and evaluate the condition of the sacrum. 4. Echocardiogram: This ultrasound of the heart is used to detect any associated heart defects. 5. Contrast study of the lower colon: This technique, called a distal colostography, involves injecting a contrast agent into the distal mucous fistula to better identify the exact location of the rectal pouch and any fistula. 6. MRI of the pelvis: This imaging study provides a clearer look at the pelvic floor muscles, the location of the rectal pouch, and any potential fistula. It can also be used to check the progress of anatomical development after surgical treatment. These tests help doctors diagnose and evaluate the severity and location of the imperforate anus, as well as identify any associated conditions or abnormalities.

How is Imperforate Anus treated?

Imperforate Anus, also known as anorectal malformations (ARMs), can be treated through surgery. The specific surgical procedure used is called posterior sagittal anorectoplasty (PSARP), which involves reconstructing the anus and rectum through a surgical cut in the perineal area. This procedure may be done in one go or in three stages, including the colostomy, the PSARP, and the closing of the colostomy. The definitive repair is typically done 4-8 weeks later if the newborn is growing well, well-nourished, and free from infections. Post-surgical care involves managing pain and performing anal dilation to prevent narrowing of the anus. The colostomy can be closed once the appropriate size is achieved, usually after 6-12 months.

What type of doctor should I see for Imperforate Anus?

A pediatric surgeon or a pediatric urologist.

Imperforate Anus

What is Imperforate Anus?

An imperforate anus, also known as anal atresia, is a condition a baby is born with, where the normal opening to the anus is not present. This condition is a type of anorectal malformation (ARM); these are a variety of abnormalities ranging from minor issues like a thin cover over the anus, to complicated conditions where the urinary and sexual organs are also affected. Because of this variety, the outcomes for each infant with ARM can differ widely.

It’s common for the muscles in the pelvis, including the muscles that control the anus (external anal sphincter), and the nerves in this area, to not be fully developed in babies with ARM. Surprisingly, about half of the babies with ARM also have issues with the development of other organs. These issues most commonly involve the organs in charge of reproduction and urination (genitourinary system) and the network of muscles and bones (musculoskeletal system).

Despite regular checks after birth, in about one in five newborns this condition might not be detected early, which can lead to increased health problems (morbidity) and possibly a higher death rate (mortality).

What Causes Imperforate Anus?

The exact cause of anorectal malformations isn’t known; chances are it’s due to a mix of different factors. Sometimes these conditions seem to run in families, as we see 1.4% of cases have a family history. Certain syndromes like Currarino syndrome, Townes-Brock syndrome, and Pallister-Hall syndrome show signs of these conditions passing from parent to child. The likelihood of having an anorectal malformation is higher if there is a genetic condition like trisomy 13, 18, or 21.

Around half the people with anorectal malformations also have other abnormalities. The risk for these extra abnormalities is higher if the level of the anorectal malformation is even further from the norm. The abnormalities could be in the genital or urinary system, the spine, the face, the heart, the spinal cord or elsewhere in the gut. Research has also shown that risk factors for having a child with an anorectal malformation include the father smoking, and the mother being overweight, obese, or having diabetes.

Imperforate anus (when the opening to the anus is missing or blocked) often happens together with other birth defects. These are known as VACTERL Syndrome/Associations, a term where each letter stands for a type of defect:

* Vertebral defects – for example smaller than usual or half-formed back bones
* Anal defects – anal atresia/imperforate anus
* Cardiac defects – heart problems, like ventricular septal defects, atrial septal defects, or tetralogy of Fallot
* Tracheoesophageal fistula (an abnormal connection between the windpipe and the food pipe)
* Renal defects – problems with the kidneys forming, or other issues in the genital or urinary systems
* Limb defects – missing or misplaced fingers or toes, too many fingers or toes, or fused fingers or toes

To be diagnosed with VACTERL/VACTER associations, at least 3 of these defects must be present.

Anorectal malformations can also be a sign of other syndromes like MURCS (Mullerian duct aplasia, renal aplasia, and cervicothoracic somite dysplasia), or OEIS (omphalocele, exstrophy, imperforate anus, and spinal defects).

Doctors have different systems to classify anorectal malformations. The classification system called “Wingspread” from 1984 categorized them into high, intermediate, or low malformation. The category is based on how high or low the end of the rectal pouch is relative to the levator ani muscle, a muscle in the lower pelvis. This system had separate categories for males and females, as well as categories for special cases and unusual malformations. The category would help the doctor decide what type of surgery to use.

However, in 1995, Dr. Pena and colleagues found that the type of fistula (an abnormal connection) present could also affect the outcome for the patient. He developed a classification system based on the type of fistula. Knowing the position and type of fistula helps guide the surgeon on what type of surgery to do and how much they need to move the blind pouch during surgery.

In 2005, the Krickenbeck group modified Pena’s classification system to make it easier to compare the results of different surgeries for patients with anorectal malformations. This system allows for standardization in diagnosing and classifying the conditions, deciding on surgical procedures, and judging the post-surgery results.

Risk Factors and Frequency for Imperforate Anus

Imperforate anus is a health condition that affects about 1 in 5,000 new births in the U.S. It’s a bit more common in males than in females. In males, the most common issue related to this condition is a rectourethral fistula, while in females it’s a rectovestibular fistula.

Signs and Symptoms of Imperforate Anus

Anal atresia, a condition in which the anus is not developed properly, can be suspected during a routine post-birth checkup. This can also be suspected when a newborn does not pass a bowel movement within 24 hours after birth, which is their first stool known as meconium. Some other signs of this condition can be abdominal bloating and meconium coming out via an abnormal opening around the perineum or the urethra.

Doctors usually examine the perineum twice, firstly at birth, and then after 24 hours. They might find there is no anal opening or just a small dent, called an anal pit, instead of an opening. The opening in the wrong place might be indicating a fistula, an abnormal connection between two body parts. This is usually situated before the muscle that controls the anus. An abnormal opening to the urinary tract might be there if stool can be seen coming out of the urethra or vagina instead of the anus. However, sometimes it may take more than a day for the fistula to manifest itself as it requires a considerable amount of pressure to push meconium through it.

In male newborns, doctors examine the urine for signs of meconium. In female newborns, a thorough examination of the area between the labia is done. Normally, there are two openings, one for the urethra and one for the vagina. A single opening might mean a condition known as persistent cloaca is present. Additionally, three openings could potentially mean a fistula is there. If there are two openings and no anus, it might indicate a rectovaginal fistula or a rectum with no exit. Babies with severe anorectal malformations may have a flat bottom or perineum, and a missing fold in the middle of the buttocks. These signs can point towards weak muscles in the perineum or sacral deformities, and can often predict a poor prognosis for gaining control of bowel movements.

Anal opening missing or presence of a small pit
Abnormal opening before the anal controlling muscle
Fistula leading to urinary tract
Signs of meconium in male newborns’ urine
In females, single, three, or two openings in the genital area along with absent anus
Flat bottom or perineum and missing buttocks fold

In patients with anorectal malformation, it is common to find other associated malformations. Therefore, doctors perform a thorough checkup to find these. For instance, the existence of specific findings on the physical exam could potentially point towards a particular syndrome, like vertebral defects or irregularities of the radial bone in the arms. To check for esophageal atresia, a condition in which the baby’s esophagus isn’t connected correctly, a nasogastric tube is typically utilized. NB: Any irregularities of the umbilical cord at birth, such as the presence of a single umbilical artery, can suggest a potential renal malformation. A cardiovascular examination might reveal a heart murmur.

Testing for Imperforate Anus

If a patient is suspected of having an anorectal malformation, meaning a problem with the structure of their anus or rectum, doctors will need to identify the severity and location of the issue and also look for other possible related conditions. These patients often also have issues with their reproductive and urinary systems, as well as their muscles, particularly around the sacrum which is the large, triangular bone at the base of the spine.

Checking for any issues with the spine and spinal cord is really important. The doctor’s team for this will often be made up of pediatricians, neonatologists (doctors who specialize in newborns), pediatric surgeons, and pediatric urologists (doctors who specialize in urinary issues in children).

For initial screening, doctors usually rely on ultrasound imaging. This screening will include an ultrasound of the abdomen and pelvis to see if there are any abnormalities in the digestive or urinary systems, and another, specifically for the perineum (the area between the anus and the genitals), to estimate the distance between the rectal pouch (the end part of the rectum where faeces are stored until they leave the body) and the perineum.

If the patient’s abdomen starts to swell, a lateral (from the side) radiograph (a type of X-ray) can be performed while the patient is lying on their stomach to determine the location of any air in the lower part of the bowel, marked by a lead marker placed on the anal dimple (a small dent or crease in the skin). If this air is closer than 1 cm from the marker, it can signal a low severity defect; if it’s more than 1 cm away, it may indicate a more severe defect.

Doctors used to use another technique, called an invertogram (where the baby is held upside down), to determine the pouch-perineum distance, but it often made the baby uncomfortable, and the resulting crying could cause the muscles around the rectum to contract and hide the rectal pouch. As a result, many doctors now prefer to use the prone cross-lateral view instead.

Physicians will also perform an X-ray of the patient’s entire spine, from the sacrum to the tips of both wing-like iliac bones on the pelvis, to identify any vertebral anomalies and evaluate the condition of the sacrum. If there are any abnormal findings on a physical examination, X-rays of the extremities (arms, legs, hands, and feet) may also be necessary. An echocardiogram, which is an ultrasound of the heart, can be used to detect any associated heart defects.

In more complex cases, there can be a need for a contrast study of the patient’s lower colon, especially if a colostomy (making an opening in the abdomen to connect to the colon) has been performed. This technique, called a distal colostography, can better identify the exact location of the rectal pouch and any fistula (an abnormal connection within the body). This process involves injecting a contrast agent (a substance that makes the body’s structures more visible on imaging studies) into the distal mucous fistula.

Lastly, an MRI (a type of imaging study that uses a magnetic field and radio waves to create detailed images of the body’s organs and tissues) of the pelvis can provide a clearer look at the pelvic floor muscles, the location of the rectal pouch, and any potential fistula. It is potentially beneficial to have MRI performed if there is suspicion of tethered spinal cord syndrome; this is a medical condition where the spinal cord is fixed or attached at the base of the spine, which can restrict its movement. A recent progress in MRI imaging technology allows for more detailed pictures of pelvic structures, often helping doctors to determine the best surgical approach. MRI can also be used to check the progress of a patient’s anatomical development after surgical treatment of the anorectal malformation.

Treatment Options for Imperforate Anus

When a baby is found to have anorectal malformations (ARMs), which are birth defects that affect the rectum and anus, the first steps involve keeping the baby hydrated and preventing infections. Surgery is not urgently required, and the baby should receive a detailed medical evaluation during the first 24 to 36 hours after birth. Medical professionals will insert tubes for fluids, antibiotics, and to prevent stomach bloating, which also helps reduce the chance of vomiting and inhalation of food particles.

Depending on the complexity of the ARMs, any associated birth defects, and any other medical conditions present at birth, the baby may need surgery. A simple ARM might be fixed with a procedure to reconstruct the anus, while a complicated one might initially require a procedure called a colostomy. With a colostomy, part of the large intestine (colon) is diverted to an opening in the abdomen to allow stool to bypass the rectum. The definitive surgery is typically done 4-8 weeks later.

If a colostomy is required, it can divert the flow of feces, address immediate concerns of bowel obstruction or infection associated with ARMs, and help to confirm the depth of the rectum.

Currently, the go-to surgical treatment for most ARMs is a procedure called posterior sagittal anorectoplasty (PSARP), which involves reconstructing the anus and rectum through a surgical cut in the perineal area, the region between the anus and the genitals. This procedure may be done in one go, or it might be performed in three stages. These stages include the colostomy, the PSARP, and then the closing of the colostomy. Usually, this definitive repair is done 4-8 weeks later if the newborn is growing well, well-nourished, and free from infections.

Post-surgical care typically involves managing pain and, in some cases, using a urinary catheter for patients having genitourinary repairs. Two weeks after surgery, patients undergo a procedure to stretch the anus to prevent it from narrowing. Once the appropriate size is achieved, usually after 6-12 months, and no skin narrows have developed, the colostomy can be closed.

Parents need to be educated about how to manage aftercare, such as how to perform anal dilation and treat diaper rash, which may develop as the patient’s skin is exposed to feces for the first time after the colostomy closure. Achieving a regular bowel movement pattern may take a few months. For the best results, these procedures should be done by an experienced surgeon in a high-volume facility.

Usually, newborn babies with imperforate anus (a birth defect where the opening to the anus is missing or blocked) are diagnosed early. However, some babies with complicated abnormalities and perineal fistulas (an abnormal connection between the rectum and the skin near the anus) might not be detected immediately. Imperforate anus can lead to a range of physical differences from a simple membrane covering over the anal dimple to complex defects with fistulous disease.

Babies with these conditions need specialized care from skilled medical professionals in high-end care centers. It’s also essential for these babies to be checked for other associated abnormalities or disorders. Full and thorough tests are essential to ensure nothing is missed.

What to expect with Imperforate Anus

Anorectal malformations are complex conditions that, along with any associated abnormalities, can greatly affect a person’s quality of life. Patients with less severe forms of these malformations, referred to as ‘low lesions,’ are more likely to gain control over bowel movements.

For many patients, these conditions can result in either constipation or lack of bowel control, known medically as ‘incontinence.’ To manage these symptoms, they may need to modify their diet or take laxatives regularly. It’s important to note that these patients will need ongoing medical care throughout their lives.

Possible Complications When Diagnosed with Imperforate Anus

If this condition is not diagnosed early in newborns, they might get dehydrated, start vomiting, get an infection in the bloodstream or lungs due to harmful substances entering the wrong passageway. Complications such as surgical site infections, healing complications where the wound reopens, and urinary tract infections can occur after most surgeries in the belly area.

Complications specific to the surgical repair of Anorectal Malformations (ARMs) can include the fistula (abnormal connection between two body parts) coming back or not going away, narrowing of the anus, narrowed reconstructed structures, or the rectum protruding out of the anus.

The long-term results typically depend on how complicated the malformations and accompanying anomalies (for example, irregularities in the vertebral column or the spine) are. Those suffering from severe vertebral irregularities, spinal cord binding (inappropriate fusion of tissues), or complicated ARMs might be disabled for the rest of their lives.

Common Complications: