Pediatric Surgery

Pediatric surgery

Hirschsprung disease

Hirschsprung disease is a congenital disorder of the colon that causes a functional obstruction to the passage of stool.The disease is characterized by a lack of ganglion cells--nerve cells that coordinate peristalsis of the bowel--in the rectum and occasionally in the entire colon, or even the small intestine.The diagnosis of Hirschsprung disease may be made in a newborn because of late passage of stool, vomiting, or severe abdominal distension.Sometimes, Hirschsprung disease is not detected until later in childhood as part of the evaluation of severe constipation. Infants and children with Hirschsprung disease can become extremely ill due to a condition called enterocolitis, in which the colon becomes very dilated and inflamed. Children with this complication can die if treatment is not instituted immediately.

Diagnosis

The definitive diagnosis of Hirschsprung disease is made by obtaining a biopsy of the rectum.This can usually be done with the child awake since there is no sensation of pain in the rectum.The biopsy is obtained using a device narrower than a pencil that is passed into the anus.If no ganglion cells are seen in the specimens obtained, then Hirschsprung disease is diagnosed.Children suspected of having Hirschsprung disease will also undergo a barium enema.This will often show a "transition zone" where dilated colon becomes narrow at the point where there are no ganglion cells.This test is important for planning operative treatment.

 Dialated colon
 Massively dilated colon in a child with Hirschsprung disease.

Treatment

The ultimate treatment of Hirschsprung disease involves an operation that brings colon containing ganglion cells--normally contracting colon--down to a point just above the anus.If an infant or child is not severely ill when the diagnosis is made, this operation can often be done within a week of the diagnosis.However, some patients are extremely ill when they first present with Hirschsprung disease because of enterocolitis or a dramatically dilated colon from long-term obstruction.In these children, it is necessary to perform a colostomy to allow the colon to decompress.After several months, the definitive "pull through" operation can be performed.

The operation

The definitive operation for Hirschsprung disease has a number of variations, all of which are effective.We use an operation called the Soave endorectal pullthrough.We usually perform this operation using a minimally-invasive technique that avoids an abdominal incision and usually requires only the placement of a single three millimeter wide laparoscope into the abdomen.The mucosa or inner lining of the rectum is removed through the anus and the colon with normal ganglion cells is "pulled through" the remaining cuff of rectal muscle to near the anus where it is sewn in place.The laparoscope is used only to monitor the process of pulling the rectum through and occasionally to assist with dividing the blood vessels to the colon.

Before the operation, it is very important that the colon be well-irrigated and any enterocolitis be under control. This may require from several days to a week of antibiotics, rectal irrigations, and dilations.

In cases where it had been necessary to place a colostomy, we still can use a relatively minimally invasive technique, but an abdominal incision must still be made to take down the colostomy.

Postoperative course

After the operation children are permitted to eat once bowel function has returned, and they may then be discharged home.This is usually within one to two days of the operation when the minimally invasive procedure has been used.Many children have difficulties with severe diaper rash after the operation due to an increased frequency of stool output.This persists until there has been accommodation to the operation.We instruct parents in the application of various cream preparations that reduce the severity of the inflammation in the skin around the anus. After several weeks we begin a regimen of occasional dilatation of the rectum that can be performed at home. In addition we usually ask parents to give rectal irrigations for three months after the operation in order to decrease the incidence of colon infection.

The long-term results from pullthrough operations for Hirschsprung disease are quite good.However, children are still at risk for the development of enterocolitis in the colon that remains, even though it has ganglion cells.This presents as fever, abdominal pain, abdominal distension, and possibly bloody diarrhea.Urgent medical attention must be obtained.

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