Imperforate anus is a condition in which the anus is absent. It is diagnosed at birth by physical exam. It occurs in approximately one in 5,000 births and occurs slightly more frequently in males.
There are many different types of defects that present as imperforate anus. The defects are often referred to as low or high, depending on where the end of the intestine is. Your doctors are able to evaluate the type of defect by performing a series of tests. An X-ray may be done which can show where the meconium (baby’s first bowel movement) is in relation to the perineum. An ultrasound can also be useful in determining the relation between the meconium-filled bowel and the perineum.
Imperforate anus may also be associated with a fistula (tunnel connecting) between the rectum and either the urethra in boys or the vagina in girls. In some very low defects, there may be a small fistula to the skin of the perineum where some meconium drains. In the cases of fistulas to the bladder, these children may have multiple urinary tract infections.
Imperforate anus can be associated with other birth defects. The term VACTERL is an acronym that defines a set of birth defects that are often found in relation to one another and may occur in children with imperforate anus. VACTERL stands for: Vertebral defects, Anal atresia, Cardiac anomalies, Tracheoesophageal fistula, Esophageal atresia, Renal anomalies, and Limb anomalies. These associated conditions can be evaluated by physical exam and by radiographic studies.
Treatment of imperforate anus depends on multiple factors, including where the bowel ends (how high or low the defect) and whether or not it is associated with other abnormalities of the perineum, mainly if there is any associated defect with the bladder or urethra, or the vagina.
Prior to surgery, your baby will be given fluids and antibiotics by vein, a tube will be placed into his stomach in order to remove any fluids from his GI tract, and an ultrasound will be performed to diagnose any associated abnormalities with the urinary system.
A low imperforate anus can be treated in the newborn period with a surgical procedure called a perineal anoplasty. In this procedure, an anal opening is created and the rectum is sutured down to the new anal opening.
In newborns with a high imperforate anus, the first step is to perform a colostomy to divert the stool. The child is then able to grow and develop prior to performing a pull-through operation in which the bowel is sewn down to a new anal opening in the perineum. After the new anus has matured and is soft, the colostomy may be closed.
After surgery, your child will be kept in the hospital. He will be closely monitored and given fluids and antibiotics by vein until he are passing stool and gas and tolerating a diet.
Most children who had a low defect and a perineal anoplasty go on to have normal bowel control. However, they often have difficulties with constipation requiring a stool softener or laxatives. Anal dilation is done at home for 2-4 months after surgery to assure good healing. Children with associated defects, especially spinal defects, have more difficulty with bowel function and may need special bowel training.
- Perineum – The area between the vagina or scrotum and the rectum.
- Meconium – Baby’s first bowel movement