A perineal fistula is a type of anorectal malformation (ARM) that involves a misplaced anal passage that is often narrowed. With a perineal fistula, the abnormal anal opening is located outside of the sphincter muscle complex, such that the fistula usually has very few voluntary sphincter muscle fibers surrounding it.
Perineal fistula and other anorectal malformations are generally present from birth. More than half of all patients with anorectal malformations have other conditions such as spinal abnormalities, kidney and urinary tract abnormalities, congenital heart defects or limb defects.
There is no way to determine if a fetus has a perineal fistula prior to birth. Children born with the condition may exhibit the following symptoms after they are born:
- Not passing stool the first day or two after birth
- Passing stool through a misplaced opening
- Swollen belly
- Missing or misplaced anus
Causes and Risk Factors
The causes of congenital anorectal malformations are unknown; however, environmental factors such as drug use during pregnancy may play a part. The condition occurs in one out of every 5,000 births. Males are slightly more likely to develop the condition than females.
After the child is born, the physician will perform a thorough physical exam of the infant, including examining the anus to make sure it is open and in the correct position.
If an abnormality is found during this physical exam, further tests including abdominal X-rays and abdominal or spinal ultrasounds may be done to evaluate for other anomalies.
Treatment varies from one patient to another and depends on each child’s overall health and condition type. For children with anal stenosis, a procedure known as anal dilatation can be performed periodically to stretch the muscles of the anus.
Patients with perineal fistula must undergo surgery – called posterior sagittal anorectoplasty – to move the rectum so that it can be precisely placed within the confines of the sphincter complex to allow for optimal bowel control. In this surgery, the incision is made from the rear of the body and is no longer than roughly 1.5 centimeters in a newborn.
This surgery is relatively simple for newborns who have not had time to experience complications due to the condition. For patients who are a year or more after birth, the same procedure can be performed, but complications such as an enlarged colon or constipation can require additional precautions on the part of the surgical team.
After surgery, the child will still need to have anal dilation performed to ensure the best outcome.
The knowledgeable staff in the Cedars-Sinai Pediatric Bowel Management Program and Pediatric Surgery Services will work with each patient to determine the best treatment option.