Ano-rectal malformation (ARM) in boys

Introduction

This leaflet provides information for parents / carers on ano-rectal malformation in boys including information on the condition itself and types of ARM, investigations and operations required to correct it and possible complications from them. A separate leaflet is available in relation to ano-rectal malformation in girls.

What is an ano-rectal malformation?

An ano-rectal malformation (ARM) is a congenital condition; this means it is present at birth. When a baby boy is developing in the womb, two separate tubes develop to form two separate openings:

1. The rectum and anus – which allows stool (poo) to exit the body.
2. The urethra – which allows urine (wee) to exit the body.

In a boy with an ARM the anus (bottom hole) does not develop normally and does not open in the correct position on the body. Additionally, for some boys the urethra (wee tube), bladder and kidneys are also affected.

There are several types of ARM which differ in severity. Classification is made according to where the bowel ends or opens on the body and whether there is a connection to the urinary tract. Most boys will have an abnormal connection between the bowel and the urinary tract, this is called a fistula (from the Latin word for tube or pipe).

A diagram of the normal anatomy found in boys without ARM:

What causes ano-rectal malformation?

We do not know why some boys are born with ano-rectal malformation.

How is ano-rectal malformation detected?

Usually an ARM is not detected on routine antenatal scans and only becomes apparent after your son is born. In some boys, if meconium (the baby’s first poo) has not been passed soon after birth, it may be obvious on examination that an anus is not present. In other boys, meconium may be passed in their urine which would indicate a connection (fistula) between the bowel and the urinary tract. Occasionally the anus may be present and functioning at birth, but in a slightly abnormal position; this may be observed during examination after birth, or may not be noticed until your son develops problems with constipation after a few weeks or months.

What are the different types of ano-rectal malformation in boys?

Recto perineal fistula

A recto perineal fistula is the least severe type of ARM. The anus opens slightly further forward towards the scrotum than it should. This may be obvious at birth or not detected until your son has problems with constipation. Sometimes the anus is covered with a layer of thin skin, which prevents the passage of stool.

Recto urethral fistula

A recto urethral fistula is the most common ARM in boys and is often called an ‘imperforate anus’. The anus is not visible when the baby is examined. Rather than the opening occurring on the bottom, the rectum is joined to the urethra (wee tube) via a fistula. It may be noted soon after birth that your son is passing meconium (black poo) in his urine.

Recto vesical fistula

A recto vesical fistula is a severe type of ARM in boys. There is no visible anus on the bottom (called an ‘imperforate anus’) and instead the rectum joins the bladder via a fistula. It may be noted soon after birth that your son passes meconium (black poo) in his urine.

Is ARM associated with other problems?

For some boys ARMs can be associated with other anomalies (defects) including anomalies of the urinary tract, genital tract, spine and heart. In order to identify if your son has any other problems, it is likely he will undergo an ultrasound scan of the kidneys and urinary system and also a scan of the heart called an ECHO (echocardiogram). An x-ray will also be performed to look at the bones of the spine.

Boys with an ARM sometimes have a combination of associated anomalies, which is referred to as VACTERL association. Each letter stands for an anomaly. Boys do not need all of the associated anomalies to be diagnosed as VACTERL.

V – Vertebra (spine)

A – Anus

C – Cardiac

T – Trachea (windpipe)

E – Esophagus/ Oesophagus – (food pipe)

R – Renal (kidneys)

L – Limb

How is ARM treated?

The treatment required will depend on the type of ano-rectal malformation which your son has.

For boys with recto urethral fistula or recto vesical fistula, because there is a connection (fistula) between the bowel and the urinary system, there is an increased risk of developing a urinary tract infection (UTI). To help prevent UTIs, your son will be placed on antibiotics which reduce the risk of infection. Further investigations will be required (such as a micturating cystourethrogram, or MCUG, which is an x-ray test of the urinary system) to determine what type of fistula your son has.

Whilst some boys with a recto perineal fistula may only require one operation, most boys will require three operations in total.

The first operation is performed within the first few days of your baby son’s life, due to the fact that he is unable to pass stool (poo). The operation is called a ‘stoma formation’. The surgeon will bring your son’s bowel on to the surface of his abdomen (tummy) and create an artificial opening called a stoma. The stoma allows stool to be passed directly from the surface of your son’s lower abdomen (tummy) and into a stoma bag, which is secured to the skin. You will be supported and taught to look after your son’s stoma, a skill which is quickly acquired.

The second operation usually happens when your son is between three and five months old and is called an ’anorectoplasty’. During the operation the surgeon will reconstruct the bowel, closing the fistula if there is one, and place the rectum in the correct location on your son’s bottom. Most boys will already have a muscle complex (sphincter) at the location of the newly formed opening although there may be less muscle forming the sphincter than normal. This muscle helps maintain continence by controlling the anus once it is in the correct position.

Approximately one to two weeks following the second operation, your son will require anal dilatations (stretching) to prevent the newly formed anus from narrowing as it heals. You will be taught to perform these dilatations independently as they are carried out daily. The size of the dilator will be decided by your surgeon (the first assessment (check) may be carried out under a short general anaesthetic). Over time the size increases until your son’s anus has slowly been dilated (stretched) to an appropriate size. Some boys will not need dilatations after the third operation; others may require dilatations t for a longer period. A separate leaflet is available in relation to anal dilatation; please ask if you would like one. (Anal dilatation in children).

The third operation usually occurs once your son’s newly formed anus has completely healed and has been dilated to an appropriate size to allow the passage of stool (poo). This normally happens three to five months following the anorectoplasty. During the third operation, the surgeon will assess the newly formed anus and ensure it is dilated enough to allow the passage of stool. If all is well, the surgeon will close the stoma and re-connect the bowel to allow passage of stool to the newly formed anus.

What other tests or investigations may be needed?

A micturating cystourethrogram (MCUG is an x-ray test which is used to identify any abnormalities in your son’s urinary system. A small catheter (tube) is passed into the bladder via the urethra. Some contrast medium (dye) is then injected in through the catheter to fill the bladder. The contrast medium is visible on x-ray and will allow the doctors to see where the fistula (connection) between the bowel and the urinary system occurs. A separate leaflet is available in relation to MCUG; please ask if you would like one. (MCUG in children).

Sometimes before your son’s stoma is closed, he will need to come to hospital to have an x-ray of his bowel, called a loopogram. This involves a small catheter (tube) being inserted into the stoma (or sometimes via the anus) and some contrast medium (dye) being injected. The contrast medium helps to show the outline of the bowel on the x-ray and allows the doctors to assess size and position of the bowel.

What are the possible complications / risks associated with ARM?

As with all operations there are risks. These are rare and include:

• bleeding
• bruising
• infection

There are also specific risks associated with each of the operations which your son’s surgeon will discuss with you in detail:

Stoma formation (the first operation):

Stomal stricture – the stoma becomes scarred and narrowed; further surgery may be required to correct this if it is causing a blockage.

Stomal prolapse – the bowel protrudes too far above the level of the skin; sometimes further surgery may be required to correct this.

Skin problems – the skin around the stoma becomes irritated and sore. Your stoma team will help you manage this.

Stomal ischaemia – the blood supply to the stoma is reduced; further surgery may be required to correct this.

Anorectoplasty (the second operation):

Anal stenosis (narrowing) of the newly formed anus following the anorectoplasty; the dilatations help to prevent this from happening.

Urethral stricture that is, narrowing within the urethra (tube which carries urine from the bladder and out of the body).

Recurrent fistula requiring further surgery.

Stoma reversal (the third operation):

Stenosis (narrowing) of the anastomosis site (the site where the bowel is re-joined) and also leakage from the anastomosis site in the bowel following stoma reversal.

Risks following abdominal (tummy) surgery:

The following two risks are rare but can occur after any abdominal surgery:

Incisional hernia – a protrusion of tissue through the wound that would require a further operation to resolve it.

Adhesions – scar tissue formation which can occur after any abdominal operation. It is a small but lifelong risk which may result in an obstruction (blockage) of the intestine. The main symptom of an adhesion obstruction is bile (green) vomit. If any child or person experiences bilious (green) vomiting, having had abdominal surgery at any time during their life, they should seek medical attention without delay.

Longer term complications:

Some boys may experience difficulty learning to toilet train so your son will be reviewed in our outpatient clinic to discuss progress.

Whilst many boys will, in the long term, have a ‘normal’ bowel habit, some boys will experience problems related to toileting, constipation and continence and require medication or other treatments to support them.

What are the alternatives?

Unfortunately there are no alternatives to surgery to correct ARM.

How long will my son stay in hospital and can I stay with him?

The length of time that your son will be in hospital for depends on the operation being performed but you will be advised of an estimated length of stay prior to each admission. One parent is allowed to be resident with each child on our children’s wards.

Follow up

Your son will be reviewed in the outpatients clinic between his operations and will be followed up until school age as a minimum.

Chaperoning

During your son’s hospital visits he will need to be examined to help diagnosis and to plan care. Examination may take place before, during and after treatment, is performed by trained members of staff and will always be explained to you beforehand. A chaperone is a separate member of staff who is present during the examination. The role of the chaperone is to provide practical assistance with the examination and to provide support to the child, family member/ carer and to the person examining.

Contacts

For further information/ queries please contact:

Your nurse specialist (Monday to Friday 08:00 to 18:00), telephone 01223 586973

The ward your child was on …………………………….