Evaluation and Management of Persistent Problems After Surgery for Hirschsprung Disease in a Child

Abstract

Hirschsprung disease occurs approximately once in every 5000 live-born infants. It is characterized by the absence of ganglion cells in the myenteric and submucosal plexuses of the intestine. Once the diagnosis of Hirschprung disease has been made, most patients are now treated with a transanal approach to resection. We review the early and late postoperative complications. Late complications include persistent mechanical obstruction, recurrent or acquired aganglionosis, disordered motility in the proximal colon or small bowel, internal sphincter achalasia, or functional megacolon caused by stool-holding behavior. These children require complex interdisciplinary care to ensure an adequate quality of life.

Hirschsprung disease was described by Harald Hirschsprung in 1887 and occurs approximately once in every 5000 live-born infants. It is a developmental disorder of the enteric nervous system and is characterized by the absence of ganglion cells in the myenteric and submucosal plexuses of the intestine ^(1,2). This results in absence of peristalsis in the affected bowel and the development of functional intestinal obstruction. Most cases are diagnosed in the neonatal period because of a distended abdomen, failure to pass meconium, and bilious aspirates or vomiting with feeding intolerance ⁽³⁾. Some children present later with chronic constipation. Commonly, the onset of constipation is around the time when solids are initiated. Although most children who present after the neonatal period have short segment disease, this same history may also be found in those with longer segment or even total colonic involvement. Children with Hirschsprung disease may also present with enterocolitis, a potentially life-threatening condition of unclear etiology that is characterized by fever, abdominal distention, and diarrhea ⁽⁴⁾.

The diagnosis is suspected on the basis of a clinical picture and plain abdominal radiographs showing distal colonic obstruction. A contrast study reveals the affected aganglionic segment as a relatively narrow region, which begins at the anus and connects to the dilated normal ganglionic segment via a “transition zone,” although these findings may be absent in as many as 10% of newborns with Hirschsprung disease ⁽⁵⁾. Anorectal manometry also can aid in the diagnosis of Hirschsprung disease by identifying absence of the recto-anal inhibitory reflex in response to rectal distension ⁽⁶⁾. This reflex is present in normal children but absent in the vast majority of children with Hirschsprung disease ⁽⁷⁾. A recent review of diagnostic tests showed that the most accurate tests for the diagnosis of Hirschsprung disease are rectal suction biopsy and anorectal manometry ⁽⁸⁾. Suction biopsy is generally thought to be accurate in children up to 3 years of age ^(8,9).

The goals of surgical management for Hirschsprung disease are to remove the aganglionic bowel and reconstruct the intestinal tract by bringing the normally innervated bowel down to the anus while preserving normal sphincter function. The first definitive treatment for Hirschsprung disease was described in 1949 by Swenson et al ⁽²⁾, who recommended rectosigmoidectomy with an end-to-end anastomosis just above the anal sphincter, done by prolapsing the rectum and pulled-through bowel outside the anus. Subsequent modifications of this operation have attempted to avoid the theoretical risk of injury to pelvic nerves and blood vessels, by avoiding complete rectal dissection. The Duhamel operation leaves the native rectum in situ, and the normally innervated colon is brought behind the rectum in the presacral space ⁽¹⁰⁾. An end-to-side anastomosis is then done, and the 2 lumens are joined. The Soave procedure (or endorectal pull-through) consists of a mucosal proctectomy with preservation of the rectal muscular cuff, and the normally innervated colon is pulled through the muscular cuff and anastomosed just above the dentate line ⁽¹¹⁾.

For many years after the original description by Swenson et al ⁽²⁾, most children with Hirschsprung disease were given a colostomy, and definitive reconstruction was done at a later time. In the 1980s, several surgeons began to report 1-stage pull-through procedures without the use of a defunctioning colostomy, even in smaller children ⁽¹²⁾, and this approach has been increasingly adopted. Despite this, it is still universally accepted that a stoma may be indicated for children with severe enterocolitis, perforation, malnutrition, or massively dilated proximal bowel, and in situations in which there is inadequate pathology support to reliably identify the transition zone on frozen section.

With the popularity of laparoscopic surgery in the early 1990s, many pediatric surgeons began to include these techniques in their practices. Georgeson et al ⁽¹³⁾ were the first to describe a laparoscopic approach to surgery for Hirschsprung disease. Their operation involves laparoscopic biopsy to identify the transition zone, laparoscopic mobilization of the rectum below the peritoneal reflection, and a short mucosal dissection from below. The transanal Soave procedure uses the same mucosal dissection from below as the Georgeson operation, but without the laparoscopic intraabdominal mobilization of the rectum ^(14,15). The submucosal dissection is continued for several centimeters, then the dissection is continued full thickness on the rectal wall, dividing the vessels as they enter the rectum. The entire rectum and part of the sigmoid colon can be delivered through the anus. The transition zone is identified, and the anastomosis is done from below. Both the laparoscopic and the transanal approaches seem to be associated with shorter hospital stay, less pain, earlier feeding, and better cosmetic results than the open procedures ⁽¹⁶⁾.

Long segment Hirschsprung disease is usually defined as a transition zone that is proximal to the mid-transverse colon, and occurs in approximately 5% to 10% of all patients. This group of patients tends to present at an earlier age, has an equal male-to-female incidence (compared with shorter segment disease, which has a 4:1 male predominance), and has a higher risk of enterocolitis both before and after surgical repair. The surgical approach to long segment disease is similar to that for standard Hirschsprung disease, except that most surgeons use a preliminary stoma. Definitive reconstruction can be done with a straight pull-through by use of any of the previously described operations. Some surgeons prefer to use a “colon patch,” anastomosing either the left colon (the Martin procedure) or the right colon (the Kimura procedure) to the pulled-through small bowel, in an attempt to maximize water absorption and decrease stool frequency ⁽⁴⁾.

POSTOPERATIVE COMPLICATIONS

Early Postoperative Complications

The complications of surgery for Hirschsprung disease include the general group of complications of any abdominal surgery, including bleeding, infection, injury to adjacent organs, and the risks of anesthesia. Children who undergo a staged procedure with a preliminary stoma may experience stoma-specific complications, including stricture, retraction, prolapse, and skin breakdown ⁽¹⁷⁾.

Anastomotic complications, although uncommon, can be seen after any of the pull-through procedures. Great care should be taken during the pull-through to prevent twisting of the anastomosis (Fig. 1). Anastomotic leak occurs infrequently and can be avoided by close attention to adequate blood supply of the pulled-through bowel and to minimizing tension on the anastomosis. Although it has never been studied in a prospective fashion, to our knowledge, the incidence of anastomotic leak in series of laparoscopic and transanal pull-throughs seems to be lower than that reported in the older literature of open pull-throughs. Strictures and retraction of the pull-through may also occur as a result of poor blood supply and tension (Fig. 2). Anastomotic stricture is also generally thought to be less common with the Duhamel procedure and in patients undergoing a 1-stage reconstruction.

FIG. 1: Early postoperative contrast enema showing torsion of the pulled-through bowel. This complication can be avoided in most cases by strict attention to the orientation of the bowel during the operation. Early recognition and repair is usually possible.

FIG. 2: Stricture after a Soave procedure. The pulled-through bowel has retracted and resulted in a tight ischemic narrowing.

Perianal excoriation is seen in as many as 50% of children undergoing pull-through surgery and tends to be more common in children with long segment disease. This complication is best managed by the use of barrier creams, and the help of a stomal therapist is extremely important. In some cases perineal excoriation may be a manifestation of low-grade enterocolitis, and metronidazole can be helpful.

Late Complications

Long-term problems in children with Hirschsprung disease include ongoing obstructive symptoms, incontinence, and enterocolitis. Quite often an individual child may have a combination of problems. The incidence of these problems varies in the literature but ranges up to 50% in some series, likely as a result of increased recognition ⁽¹⁸⁾.

Obstructive Symptoms

Obstructive symptoms may take the form of abdominal distension, bloating, vomiting, or ongoing severe constipation. Many of these children have postoperative symptoms that are identical to their symptoms at initial presentation. In some cases, the child will have a good response to surgery and then experience obstructive symptoms later. In other cases, the child may not have any improvement in the postoperative period.

The major reasons for persistent obstructive symptoms after a pull-through are shown in the following ⁽¹⁹⁾:

Persistent Obstructive Symptoms

• Mechanical obstruction
• Persistent or acquired aganglionosis
• Colonic motility disorder
• Internal sphincter achalasia
• Stool-holding behaviour

Incontinence

• Abnormal sphincter function
• Abnormal sensation
• “Overflow” incontinence due to constipation

Enterocolitis

• Obstruction
• Genetic or immunologic predisposition
• Abnormal mucin

Mechanical Obstruction

Mechanical obstruction may result from a stricture after any of the pull-through operations, or from a retained aganglionic spur after a Duhamel procedure, which may fill with stool and obstruct the pulled-through bowel (Fig. 3A). The Duhamel procedure may also be complicated by a kink at the top of the anastomosis, which leads to obstruction (Fig. 3B). These complications can be identified by a combination of digital rectal examination and contrast enema. Although some strictures can be managed by repeated dilatations, many require revision of the pull-through ⁽²⁰⁾ (Fig. 4). Duhamel spurs can be resected from above or managed by extending the staple line from below, with or without the aid of laparoscopic visualization.

FIG. 3: Obstructive complications after the Duhamel procedure. A, Anterior aganglionic spur. Because it is aganglionic, stool gradually fills the spur, and ultimately it causes obstruction owing to direct compression of the pulled-through bowel. B, Kink at the top of the side-to-side stapled anastomosis.

FIG. 4: Revision of a pull-through complicated by a stricture. The Duhamel procedure is preferred for this situation.

Obstructive symptoms can also be caused by small bowel obstruction due to peritoneal adhesions, and can occur many years after surgery. The diagnosis can be made from a picture of dilated bowel loops with air-fluid levels on plain abdominal radiographs. In some cases in which the obstruction is intermittent or partial, a contrast study with small bowel follow-through may be helpful.

Persistent or Acquired Aganglionosis

Although rare, some children may have persistent aganglionosis. This may be caused by a pathologist's error ⁽²¹⁾ or a transition zone pull-through, and in some cases there may be ganglion cell loss after a pull-through ⁽²²⁾. It is imperative to do a rectal biopsy on the pulled-through bowel to determine whether normal ganglion cells are present; if there are not, most children should undergo a repeat pull-through. This can be done by use of either a Soave or a Duhamel approach ^(23,24).

Motility Disorder

It is well recognized that children with Hirschsprung disease may also have associated motility disorders, which may be focal (usually involving the left colon) or diffuse. In some cases, these abnormalities may be associated with histological abnormalities such as intestinal neuronal dysplasia ⁽²⁵⁾. In children who have been shown not to have a mechanical obstruction and who have normal ganglion cells on rectal biopsy, investigations for motility disorders should be undertaken. This can include a radiopaque sitzmarker transit study, colonic manometry ⁽⁶⁾, and laparoscopic biopsy in a search for intestinal neuronal dysplasia ⁽²⁶⁾. If a focal abnormality is found, then consideration should be given to resection and repeat pull-through using normal bowel. If the abnormality is diffuse, then the appropriate treatment is medical and includes bowel management and the use of prokinetic agents.

Internal Sphincter Achalasia

Internal sphincter achalasia refers to the nonrelaxation of the internal anal sphincter that is present in all children with Hirschsprung disease because they lack a normal recto-anal inhibitory reflex. Most children with Hirschsprung disease are able to overcome this nonrelaxation, but in some children it may result in persistent obstructive symptoms. Traditionally, the treatment for this was internal sphincterotomy or myectomy, which is still recommended by many surgeons ⁽²⁷⁾. Other authors have suggested the use of intrasphincteric botulinum toxin ⁽²⁸⁾ (Fig. 5) or the application of nitroglycerine paste ⁽²⁹⁾, both of which relax the sphincter in a reversible fashion. The advantage of the latter approaches is that they do not result in any permanent damage to the sphincter, and in most cases the obstructive symptoms from internal sphincter achalasia tend to resolve spontaneously over time and are gone by the age of 5 years. In many cases, repeated injection of botulinum toxin or the application of nitroglycerine paste is necessary during the wait for resolution of the problem ⁽³⁰⁾. Botulinum toxin can also be used as a diagnostic test, in the sense that absence of a clinical response to botulinum toxin suggests that the sphincter is not the problem and that myectomy is likely to fail.

FIG. 5: Injection of botulinum toxin for the treatment of internal sphincter achalasia. The procedure is done under general anesthesia. Multiple injections into the sphincter are done circumferentially at the level of the dentate line.

Functional Megacolon

There remains a group of children who do not have an identifiable cause of their symptoms and who do not respond to surgical or chemical relaxation of the sphincter. Most of these children have stool-holding behavior and are best treated by a bowel management regimen consisting of laxatives, enemas, and behavior modification, including support for the child and family. In some severe cases of obstructive symptoms, the child may be best served by use of a cecostomy ⁽³¹⁾ and the administration of antegrade enemas, or by the creation of a proximal stoma.

An algorithm for the investigation and management of obstructive symptoms in a child is shown in Figure 6. Consideration should also be given to initial evaluation for functional constipation and to continuation with the algorithm if the history is inconsistent with functional constipation or if the patient does not respond to treatment.

FIG. 6: Algorithm for the investigation and treatment of a child with obstructive symptoms after a pull-through procedure.

Incontinence

There are several reasons for a child to be incontinent after a pull-through: abnormal sphincter function, abnormal sensation, or “overflow” incontinence due to constipation, and loss of the rectocolonic inhibitory reflex. Abnormal sphincter function may be due to sphincter injury during the pull-through or to a previous myectomy or sphincterotomy. Several techniques exist for identifying this kind of injury, including anorectal manometry ⁽³²⁾, anal sonography ⁽³³⁾, and direct examination of the anal canal in a search for the dentate line ⁽³⁴⁾. Abnormal sensation may involve either lack of sensation of a full rectum (which can also be identified by use of anorectal manometry) or injury to the transitional epithelium, which permits differentiation between gas, liquid stool, and solid stool. This injury may occur during a pull-through, especially if the anastomosis is too low.

Most children with incontinence after a pull-through have overflow of stool because of ongoing constipation. Once sphincter injury and a problem with sensation have been ruled out, the obstructive symptoms should be investigated and the child treated as described in the previous section.

An additional problem seen in some children is excessive motor activity in the proximal colon combined with loss of the native rectum, which leads to loss of the normal rectocolonic inhibitory reflex. These high-amplitude contractions may also cause incontinence ⁽⁸⁾.

Enterocolitis

As mentioned previously, enterocolitis may be a presenting feature of Hirschsprung disease; however, it may also occur after surgical correction of the disease. Although the clinical features of enterocolitis are generally agreed upon (fever, abdominal distention, and diarrhea), a precise definition has not yet been developed. There is therefore wide variation in the reported incidence of this problem postoperatively, with estimates ranging from 17% to 50%, calling into the question the specific clinical definition of enterocolitis ⁽¹⁸⁾. Enterocolitis also seems to be more common in children with longer segment disease and those with trisomy 21 ⁽³⁵⁾. The absence of enterocolitis preoperatively does not ensure that the child will not experience enterocolitis in the postoperative period ⁽³⁶⁾. A recent study has implicated the presence of intestinal neuronal dysplasia as a risk factor for the development of postoperative enterocolitis ⁽³⁷⁾. Abnormal mucin, particularly MUC-2, has also been implicated in increased susceptibility to enterocolitis caused by the decreased intestinal barrier ⁽³⁸⁾.

The treatment of postoperative enterocolitis is largely symptomatic and involves bowel rest with nasogastric drainage, intravenous fluids, broad-spectrum antibiotics, and decompression of the rectum and colon by use of rectal stimulation and irrigations. The risk of enterocolitis can be minimized by the use of prophylactic measures such as routine irrigations ⁽³⁹⁾ or the long-term administration of metronidazole, particularly in those who are thought to be at higher risk for this complication ⁽⁴⁰⁾. Inasmuch as enterocolitis is the most common cause of death in children with Hirschsprung disease and can occur postoperatively even in patients who did not have it preoperatively, it is extremely important that the surgeon educate the family about the risk of this complication and urge early return to the hospital if the child should experience any concerning symptoms ⁽⁴¹⁾.

Children with total colonic Hirschsprung disease are at particular risk for ongoing enterocolitis, and those who have had a colon pouch procedure such as a Martin or Kimura reconstruction are at even higher risk. In these children, the retained aganglionic colon tends to dilate over time and act as a source of bacterial overgrowth (Fig. 7). The best approach for these children is to resect the colon pouch, which can often be done without revising the pull-through.

FIG. 7: Contrast enema in a 10-year-old child who underwent a Martin procedure for total colonic Hirschsprung disease as an infant. The “ileo-rectum” is extremely dilated and acts as a source of bacterial overgrowth. This child was successfully treated by surgical excision of the retained aganglionic rectosigmoid, without revision of the pull-through.

Long-term Prognosis

Despite the relatively common occurrence of postoperative complications, there is evidence from long-term follow-up studies that most children with Hirschsprung disease overcome these issues and do well ⁽⁴²⁾. Obstructive symptoms and incontinence seem to resolve with time, and the risk of enterocolitis, in the absence of an ongoing obstructive cause, is almost eliminated after the first 5 years of life. Sexual function, social satisfaction, and quality of life seem to be relatively normal in the vast majority of patients. It is too early to determine what effect newer approaches, such as the single-stage pull-through and the use of minimal access surgical techniques, will have on the postoperative complication rate and the long-term outcome, but this is an important question that will require close follow-up and analysis.