Anorectal Malformations in Children: What Causes Anorectal malformation and How to Correct Them?
What is anorectal malformation?
Anorectal malformations are congenital birth defects that occur during pregnancy. The malformation occurs in the lower part of the digestive tract where the anus and rectum do not form properly.
Types of anorectal malformation:
Abnormalities in both male and female:
- Imperforate anus: The absence or misplacement of the anal opening.
- The presence of membrane or tissue over the anal opening.
- Rectal atresia and stenosis: Narrowing of anus or rectum where the passing of stool is difficult.
- Rectoperineal fistula: An abnormal connection between the rectum and perineum. Abnormalities in male:
- Rectobulbar urethral fistula and rectoprostatic fistula: The rectum is linked with the urethra.
- Rectobladder neck fistula/rectovesical fistula: The rectum is linked to the bladder. Abnormalities in female:
- Rectovestibular fistula: The rectum is linked to the exterior of the vagina (vulval vestibule).
- Cloaca: A channel formed where the vagina, rectum, and urinary tract are connected to each other.
What causes anorectal malformation?
A baby’s lower part of the digestive tract starts forming early during pregnancy. In later weeks, while the baby is growing in the uterus, many other organs undergo development. There are some events that must occur for the rectum and anus to separate from the urinary tract in order to form normal anatomy, but sometimes, these events do not occur and it leads to malformation of the rectum and anus. The cause is usually not known but in some cases, it is hereditary. Anorectal abnormalities can be associated with genetic syndromes or other congenital anomalies such as:
- VACTERL: A disorder with abnormalities of the vertebrae, anus, heart, trachea, esophagus, kidneys, and limbs.
- Abnormalities of the spine
- Abnormalities of the urinary tract
- Abnormalities of the digestive system
- Down syndrome
- Townes-Brocks syndrome: Abnormalities of the anus, kidneys, ears, and limbs.
- Currarino’s syndrome: Malformation of the lower spine (sacrum), presacral mass, and anorectal.
- Pallister-Hall syndrome: A condition that involves fusion or having extra fingers and/or toes. Imperforate anus may also be a feature of this condition.
What are the correcting surgical options?
In most cases, surgery is the only option but the type of surgery depends on the medical condition.
Types of surgical management for anorectal malformation include:
- A constricted anal passage: Surgery is not required. Anal dilation is performed to elongate the anal muscles.
- Anal opening covered with membrane: Surgery is required to remove the membrane covering the anus and anal dilation may be needed in case of a constricted anal passage.
- Improper connection of the rectal or anal with or without a fistula: A combination of surgeries is needed and these include:
- Colostomy: A procedure where the ends of the large intestine is brought out through the abdominal wall. The upper part forms a stoma (an opening where a bag is attached to collect stool). The lower part allows mucus to be collected into a collection bag.
- Connecting the rectum to the anus: A procedure performed in the first few months of life. Colostomies remain in place and the rectum and anus are attached. Anal dilation can be done a few weeks after surgery to prepare for the next step.
- Closing the colostomies: Performed after two or three months. After some days, the child will be able to pass stool through the rectum.
- Posterior sagittal anorectoplasty (PSARP): Also known as “pull-through procedure” where a middle sagittal incision is made. In this procedure, the rectum is placed in the right position and a new anus is formed in the perineum.
- Anterior sagittal anorectoplasty: Performed in females with rectovestibular fistula where in lithotomy position, an incision of the anterior sphincter muscle is made through the perineal and rectum is pulled through and place in the right position.
- Sacroperineal approach: Designed for high imperforate anus.
- Abdominoperineal pull-through: Performed in high or intermediate anorectal malformations.
- Sacroabdominoperineal approach: Designed for imperforate anus.
For better diagnosis and treatment, consult the best proctologist in India to receive the best surgical management of anorectal malformation at Shreyas Ano Rectal Hospital and Research Center.