The term "anorectal malformations" covers congenital malformations of the rectum and anus. These form a broad spectrum of disorders that occur in both boys and girls and can also affect the urogenital tract.

The defects develop in the fifth to seventh week of fetal development. About 1 in 4000 children are born with an anorectal malformation.

At the time of birth, the absence of the anorectal opening or anus is noticeable in the newborn or the anal opening is in an atypical location. The disease spectrum ranges from mild findings that can be treated relatively easily (and then usually have an excellent functional prognosis) to very complex malformations with a variety of diagnoses that can be corrected depending on gender.

Anorectal malformations occur slightly more frequently in boys than in girls. As with all anorectal malformations, the disease spectrum ranges from minor to complex. The most common malformation in boys is anal atresia with a connection (fistula) to the urethra (rectobulbar or rectoprostatic fistula).

The following ARMs are common in boys and are treated at our center:

Anal atresia without fistula
The colon ends blindly without a connection to the skin or another organ

Rectoperineal fistula
The fistula opens into the skin of the perineum, scrotum or penis before the anal dimple (Fig. 2)

Rectobulbar and rectoprostatic fistula
The rectum opens into the upper or lower urethra via a fistula (Fig. 3)

Bladder neck fistula
The fistula runs from the rectum into the bladder neck (Fig. 4, see also Fig.9+14+15)

Rectal atresia and rectal stenosis
The anal opening is normal, but the rectum is interrupted, e.g. by a membrane or a missing section of bowel

 

 

Anorectal malformations are somewhat rarer in girls than in boys. As with all anorectal malformations, the disease spectrum ranges from mild to complex. The most common variant in girls is the rectovestibular fistula. Most "high anal atresias" (a term that is now rarely used) are so-called cloacal malformations. A rectovaginal fistula is an absolute rarity.

The following ARMs are common in girls and are treated at our center:

Anal atresia without fistula
The colon ends blindly without a connection to the skin or another organ

Rectoperineal fistula
The fistula opens in front of the anal dimple between the dimple and the vaginal vestibule

Rectovestibular fistula
The fistula opens into the vaginal vestibule, most common form in girls

Cloacal malformation
The bowel, vagina and urethra open into a common canal. The length of this common canal can vary. If it is longer than 3 cm, the operation is more complex

As a rule, the absence of the anus or the anorectal malformation is noticed at the maternity clinic. Your child will then be referred to us from there. We will first take a close look at your child and examine the region of the anus and perineum. In addition to this "visual diagnosis", further examinations are carried out: An ultrasound examination of the abdomen, kidneys and urinary tract, heart and spinal cord; a urine examination; X-rays of the abdomen, sacrum and coccyx if necessary. These examinations are important in order to get an idea of the shape of the anorectal malformation.

After these initial examinations, we can usually make a diagnosis and discuss the next steps with you. We also offer all parents the very well-written brochures of the self-help group SOMA e.v. (www.soma-ev.de), which explain the topic of "anorectal malformation" in detail and in layman's terms. We have found that these are generally very gratefully received by parents and that well-founded information alleviates rather than reinforces many fears.

Depending on the severity and type of malformation, only one operation or three or more operations may need to be performed. We usually perform the first operation in the first few days of life.



Here are some examples:

Rectoperineal fistula: This is a "mild or deep form" of ARM. Soon after birth, we perform a relatively superficial, standardized operation. This involves moving the mouth of the rectum (the fistula) to the actual target location (anal dimple). As a rule, no further operations then follow.
If your child passes enough stool via the fistula, this operation does not have to be performed in the first few days. As a rule, this form of ARM does not require an artificial anus.

Rectovestibular fistula: This is also a "mild or deep form" of ARM. A relatively superficial, standardized operation is also performed here. The opening of the rectum in the vaginal vestibule (the fistula) is moved to the actual target location (anal dimple). As a rule, no further operations then follow.
If your child passes enough stool via the fistula, this operation does not have to be performed in the first few days. If the fistula is very small and cannot be dilated, an artificial anus must be temporarily inserted.

Complex forms (e.g. with a fistula connection to the urinary tract) or cloacal malformations
These children require more comprehensive treatment. First, an artificial anus (anus praeter, colostomy) is temporarily inserted. We usually do this on the first or second day of life. The artificial anus is created by making an abdominal incision, cutting the colon, passing the two ends out through the abdominal wall and stitching them into the skin. This procedure allows the child to defecate, feed normally and thrive.

The artificial anus usually remains in place for one to three months. During this time, your child can be cared for at home. We will organize home care for you from the MHH by a special paediatric stoma therapist who can answer many questions and give you helpful advice on care during the initial period at home.


Typical artificial bowel outlet (anus praeter, colostomy) created. The large intestine is cut through an abdominal incision, the two ends are passed through the abdominal wall to the outside and sutured into the skin. This procedure allows the child to pass stool via the "feeding stoma", feed normally and thrive. The ARM can be precisely classified via the "draining" stoma using contrast medium at a later stage or before the pull-through operation (see "distal colostogram")


Pull-through operation (= actual restoration or Formation of the anal opening) usually second operation:

Before the actual restoration or formation of the anal opening (pull-through operation), it is very important to precisely classify the form of the malformation. This may require further examinations. A special X-ray examination called a "distal colostogram" (Fig. 9+10) is particularly important in order to understand your child's individual anatomy precisely, to diagnose any connection between the fistula and the urinary tract and then to choose the correct surgical approach.

In the distal colostogram, a contrast medium is introduced into the lower part of the artificial bowel outlet ("laxative limb"). This allows us to see how far the distance is between the rectal blind sac and the actual rectal opening on the skin, whether there is a fistula to the urinary tract and how it runs. The position of the rectum in relation to the sacrum can also be determined. The higher the rectum is located, the more difficult it is to reach it using only a surgical approach from the buttocks without laparoscopy (see below).


For pull-through surgery, which we perform in the first year of life (3rd-4th month or 5-6kg body weight), two procedures are used in our Clinical Department:

- PSARP (posterior sagittal anorectal plasty)

- Laparoscopically assisted anorectoplasty(LAARP)



PSARP (posterior sagittal an orectal plasty)

This surgical method can be used to treat 90% of all ARMs. It is performed in the prone position. First, the existing force for contraction is determined using electrical stimulation of the sphincter muscle. This determination can be an initial indication of the subsequent continence prognosis. We then separate the rectum from the urogenital tract with an incision exactly in the midline until there is sufficient length to suture it into the anal skin at the perineum in an anatomically correct position (Fig. 11-13).

Lifelong support

In addition to expertise in the surgical correction of colorectal diseases, the MHH has a program for long-term care. In addition to achieving the best possible functional outcome, the aim is to maximize the quality of life for patients and their families. We want to ensure long-term follow-up from day one to adolescence and help children and parents to deal with the challenges of puberty and the numerous possible problems in the long term.

After about two weeks, the surgeon will see you again in our senior physician's special consultation for anorectal malformations. During the first stage of aftercare, the anal opening will be stretched. This is to prevent scarring of the newly formed anus. Dilation (bougienage) is performed using round metal pins of various diameters, known as Hegar pins. These are moistened with plenty of lubricant (e.g. Vaseline), inserted into the anus and the scar is carefully stretched. The diameter and size of the Hegar sticks are increased over several weeks until the average anus size of a healthy child of the same age is reached. These stretches are initially performed daily, but later with decreasing frequency. Even if they can still be very uncomfortable, especially at the beginning, bougienage is very important in order to prevent scarred constrictions or closure of the newly formed anus. Once a severe narrowing (stenosis) of the anus has developed, it is very difficult to treat and can sometimes only be corrected by further surgery.

In our experience, most parents initially find the bougienage procedure very difficult. However, after we have repeatedly explained this procedure to you in detail and with a great deal of calm, and you have performed it here in our Clinical Department under supervision, you will usually manage it very well at home. However, if there are any problems, we are there for you every day by telephone and also in our outpatient clinic to provide you with help and advice. It is important to us that you do not feel left alone after the operation and that we walk the sometimes difficult path together.