Anorectal sphincter myectomy:simple forgotten operation for Ultrashort segment Hirschsprung Disease

High Index of suspicion series 1.

Simple forgotten operation for Ultrashort segment Hirschsprung Disease

Case Notes 1:

A 3.2 kg female neonate delivered by full term normal delivery referred for vomiting, abdominal distension and not passed meconium within 24 hours. She developed abdominal distension and non-bilious vomiting with refusal of feeds. The septic workup was normal, and x-ray abdomen showed gaseous distension of small and large bowel loops up to sigmoid colon (Fig.1). A Dye study showed a short spastic segment in the rectum with dilatation of proximal rectum with a transitional zone (Fig.2). Patient was put on iv fluids and Nasogastric tube decompression and with a tentative diagnosis of ultrashort segment HD a full thickness rectal biopsy was planned. Rectal manometry was not done due to a very short spastic segment. The patient passed meconium after per rectal examination. A full thickness rectal biopsy from the posterior wall of rectum 2.5 cm above the dentate line was performed under caudal anaesthesia and simultaneously 3cm long longitudinal strip of spastic circular muscle (Anorectal Myectomy) was taken and the mucosa was closed with Vikryl sutures. Histopathological examination revealed rectal mucosa with absent ganglion cells and hypertrophic nerve bundles confirming the diagnosis of Ultra short segment HD (Fig 3).

The patient did well and passed normal stools and well 4 months after surgery.

Hirschsprung disease occurs when certain nerve cells in the wall of the colon do not develop antenatally. In normal individuals without Hirschsprung disease, large muscles move gas and stool through the colon with the help of nerve cells called ganglion cells. Children with Hirschsprung disease do not have ganglion cells in the rectum. They sometimes do not have them in other parts of the colon either. Therefore, gas and stool get backed up. This can cause partial or total bowel obstruction. They can have problems passing gas and stool. Almost all children with Hirschsprung disease will need surgery.

The levels of Hirschsprung disease:

• Ultrashort segment: Missing ganglion cells in the last one to two centimetres of the rectum.

• Short-segment: Missing ganglion cells in the rectum and sigmoid colon (the last segment of the colon).

• Long-segment: Also missing ganglion cells in the first third of the colon.

• Total colonic aganglionosis: Lack ganglion cells throughout the colon. This level is the least common. It causes more severe symptoms than other forms of the disease.

Incidence

Hirschsprung disease occurs in about 1 out of 5,000 live births. It is three times more common in boys than girls. About 12% of cases are linked to a genetic disorder. This is most often Down syndrome or a rare condition called Mowat-Wilson syndrome.

About 80% of people with the disease do not have a family history of the disease. But, if one parent has Hirschsprung disease, there is about a 1% chance the child will have it too. If a couple has a child with Hirschsprung disease, there is a 4% chance that a sibling will be born with it. It appears that if a parent or child has long-segment Hirschsprung disease, the chances a sibling will be born with Hirschsprung disease are higher than if the parent or child has ultrashort or short-segment Hirschsprung disease.

Investigations:

A careful history, physical exam and testing are required to diagnose Hirschsprung disease. Abdominal X-ray: An X-ray of the belly may show a bowel obstruction. This test is a first step. It cannot give an exact diagnosis of Hirschsprung disease.

• Contrast enema: This test uses X-ray images with an enema with a contrast solution. The solution makes the features of the colon show up better on an X-ray. This is the most helpful imaging study to assist in finding out if a child has Hirschsprung disease.

• Rectal biopsy: This test gives the definitive diagnosis. A full thickness biopsy of the posterior rectal wall is taken under anaesthesia and the pathologist confirms that a child has Hirschsprung disease based on the absence of ganglion cells and other abnormal nerve-related findings. In infants, the care team does a “suction” rectal biopsy at the bedside in the hospital room. Since there are no sensory nerves at the site of biopsy, the procedure is not painful. If this is inconclusive or if the patient is older, a surgical biopsy is done under general anaesthesia in the operating room.

• Anorectal manometry: This test measures anal pressure. It also checks if normal reflexes of the rectum and the anus are present. It can be done at the bedside in the hospital room. Basically, it asses recto-sphincteric reflex.

Treatment

Each child with Hirschsprung disease has unique needs. The treatment plan has to be modified according to child’s condition and overall health.

Surgery

The surgical options are

1. Swenson’s Operation

2. Duhamel’s Operation

3. Soave’s Operation

4. Lilly’s operation for total colonic aganglionosis.

5. Anorectal sphincter Myectomy for Ultra short segment Hirschsprung’s disease.

Almost all children with Hirschsprung disease need a surgery called a “pull-through procedure". This involves taking out the diseased segment of colon. Then the rest of the colon is pulled down and connected to the anus. Sometimes, the surgeon can do this surgery using minimally invasive laparoscopic or robot-assisted surgery. This can mean less pain, less blood loss, smaller scars with faster healing and shorter hospital stays, compared to what patients may have with an “open” or traditional surgery.

Sodium Supplementation

Some patients, in particular those with long-segment Hirschsprung disease, may need sodium supplements. A simple urine test is used to check your child’s sodium levels. Your child’s primary care doctor and nutritionist, can prescribe the right oral sodium supplement. Patients who need sodium supplements need to be followed closely for growth and watched closely for dehydration.

Long-Term Outlook for Children with Hirschsprung Disease

Even after surgery, children with Hirschsprung disease may have constipation, faecal incontinence or enterocolitis. This affects their long-term outcomes. But, with a successful surgery and long-term follow-up care, most children are able to achieve normal bowel habits.

Other Treatment Options

Patients can have constipation, faecal incontinence and enterocolitis before and after surgery. A number of other treatment options exist such as bowel management, sacral nerve stimulation, and biofeedback (therapy to help improve the strength and coordination of pelvic floor muscles that are responsible for bowel and bladder control). Some times dietary modulations and probiotics for a long period are beneficial.

References:

1. Khope S, Dalal S: Recurrent post redo pull-through stricture; what is the option? Ind J Surg. June 2016

2. Khope S, Dias Ryan, Faldesai N: Ultrashort segment HD, sphincter myectomy in postnatal period is curative treatment.

Fig.1: Abdominal distension

Fig.2 Plain X-ray abdomen showing gaseous abdominal distension upto rectum taken 24 hrs after birth.

Fig.3 Dye study showing Ultra short segment spastic segment.

Fig.4 Histopathological slide. (HE X 10) showing rectal mucosa with hypertrophic nerve bundles and no ganglion cells.