Congenital megacolon has been recognized since the 17th century, but its classic clinicopathological description is attributed to Harald Hirschsprung's autopsy report of 1886. Despite this early report, the appropriate surgical treatment of Hirschsprung's disease dates to Swendon's article in 1948, which advocated resection of the histologically denervated rectosigmoid. The current mortality rate of 1 to 3 per cent reflects increased recognition of the disease, improved neonatal management, and timely surgical intervention.

Hirschsprung's disease has an incidence of 1 in 5000 births and is the most common cause of intestinal obstruction in the neonate. There is a male to female preponderance of 3.5: 1 in the more common short-segment disease and 2: 1 in long-segment disease. There is a genetic influence, with a risk of 2.5 to 6 per cent for siblings of a male propositus and 7.6 per cent for siblings of a female patient. Children who have long-segment disease convey a family risk of 9 to 12.5 per cent.

Between 5 and 9 per cent of patients with Hirschsprung's disease have trisomy 21 (Down's syndrome); 3.6 per cent of those with Hirschsprung's disease have genitourinary abnormalities. Neural crest abnormalities, such as congenital central hypoventilation syndrome (Ondine's curse) and Waardenburg's syndrome, are also associated with congenital aganglionosis. While aganglionosis was originally thought to affect only term infants, it is now recognized that 5 to 10 per cent of babies with Hirschsprung's disease are premature.

The basic defect in neuroenteric dysfunctional disorders is caused by inappropriate signals in the intrinsic nervous system of the intestinal wall. Neural crest cells migrate from somites 1 to 7 to innervate the intestines, starting in the oesophagus at week 4 of embryonic development and migrating distally until the entire intestinal tract becomes seeded. It is not clear what contributes to the failure of aboral migration which leads to distal aganglionosis. The abnormality may reside in the neural crest cells themselves, in the extracellular matrix, which may inhibit normal migration of neurogenic precursors, or neurogenic precursors may be destroyed after their migration, by vascular or possibly immune mechanisms. Whatever the aetiology, the failure of normal neurogenic precursors to enter the most distal hindgut results in abnormal innervation. This segment remains contracted but otherwise appears normal. As cranial–caudad propulsive waves proceed they stop at the aganglionic segment, which therefore acts as a functional obstruction. Progressive hypertrophy and dilatation occurs in the normally innervated segment, producing the abnormal and classical congenital megacolon.

The pathological hallmark of Hirschsprung's disease is absence of ganglion cells in the submucosal plexus of Meissner and aganglionosis or hypoganglionosis in the intermyenteric plexus of Auerbach. Hypertrophic nerve trunks are scattered throughout the submucosa. Neurofibrillary elements extend abnormally into the lamina propria mucosae and an area of transition can be identified between the distal involved segment and the more proximal segment. At this point, hypertrophic nerve trunks can still be identified, but the intermyenteric plexus contains dysplastic and immature ganglion cells. Hypoganglionosis and ‘skip-area’ aganglionosis may exist or coexist.

The increased expression of cholinergic transmitters in this area can be identified by acetylcholinesterase histochemistry. This enzyme, which cleaves acetylcholine to acetate and choline, marks an area with an abundance of cholinergic nerve fibres. An impressive display of cholinergic fibres can be seen scattered throughout the submucosa and lamina propria, providing a diagnostic accuracy of 91 per cent. Staining of areas with hypoganglionosis or aganglionosis with haematoxylin and eosin stain affords an accurate diagnosis only 8.5 per cent of the time. Other stains for nerve cells, such as neurone-specific enolase, S–100, CD 11, N-cam (neural adhesion molecule) or neurofilament protein have not improved the accuracy of diagnosis.

The neonate who presents with bilious vomiting must be considered to require surgical intervention until proved otherwise. The most common presentation of a patient with Hirschsprung's disease is failure to pass meconium within the first 24 h of life and abdominal distension, with bilious vomiting or bilious gastric aspirate. Although sepsis, maternal factors, meconium plug, or ileus may be obvious, an evaluation for aganglionosis is indicated with these clinical signs and symptoms: 10 to 20 per cent of infants who have meconium plug syndrome have concomitant aganglionosis.

One-third of children with untreated Hirschsprung's disease develop enterocolitis, manifested by foul smelling diarrhoea and occasionally by hypotension, by 3 months of age, with one-third of these cases occurring within the first 30 days of life. Enterocolitis itself is the leading mortality risk in Hirschsprung's disease and needs to be treated with fluid resuscitation, broad-spectrum antibiotics and levelling colostomy to divert the faecal stream. Infants who have had enterocolitis as neonates remain at increased risk of continued enterocolitis, even after successful pull-through operations.

Plain films of the abdomen show gas-filled intestinal loops throughout the abdominal cavity and an absence of gas in the pelvis. Barium enema, often considered diagnostic, is less accurate in the neonatal period than at any other time. Transition zone narrowing and secondary proximal megacolon may not be found. If a transition zone is not identified, abdominal radiographs obtained after 24 to 48 h may disclose failure of the colon to evacuate the contrast material. This finding is highly suggestive of aganglionosis.

Failure of intrarectal distension to relax the internal sphincter complex produces abnormal anorectal manometric tracings that have an 85 per cent diagnostic accuracy for Hirschsprung's disease (Fig. 1) 2148. These studies can be performed at the bedside; however, this technique cannot be employed in children who weigh less than 3 kg or have a postconceptual age of less than 39 weeks, as the neural reflex is immature and manometric results in these groups are equivocal.

The rectal biopsy, either suction, punch or open, remains the gold standard for diagnosis (Fig. 2) 2149. The biopsy specimen must include the submucosa to allow evaluation of the presence of absence of ganglion cells. There is an area of relative hypoganglionosis in the rectum immediately proximal to the dentate line. The biopsy should be performed at least 1 cm above this area of transition. Since the rectum in the small infant is only 3 to 4 cm long, caution needs to be exercised to avoid perforation above the peritoneal reflection. Absence of ganglion cells or elevated acetylcholinesterase staining is pathognomonic for Hirschsprung's disease (Fig. 3) 2150. If the combination of punch biopsy and manometry cannot establish the diagnosis, a full-thickness, longitudinal, carefully oriented biopsy obtained under general anaesthesia is required to determine whether hypoganglionosis, aganglionosis, or other neuroenteric disorders are present.

Once the diagnosis of Hirschsprung's disease has been established, relief of the functional obstruction is important to avoid the high mortality that follows enterocolitis. Some centres have reported early neonatal pull-through procedures with excellent outcomes. Others use enemas when definitive surgery is to be performed at a later date, but the relative inconvenience and stress of this treatment to the parent and child must be considered. Currently most surgeons prefer to perform a levelling colostomy at the most distal colonic site where ganglion cells are identified.

During the initial intra-abdominal procedure frozen sections, generally 5 cm apart, are needed to identify ganglion cells in the intermyenteric plexus. Excessive and prolonged propulsive activity to overcome functional obstruction can cause the area of megacolon to extend beyond the normal ganglionic segment into the transition zone and even into the area of aganglionosis. The biopsies, performed over the taenia coli, need not enter the lumen to confirm the diagnosis of Hirschsprung's disease and are crucial when determining the site of the colostomy.

Divided colostomies are preferred to prevent carry-over of the faecal stream, but loop colostomies may be more appropriate in the severely ill baby with enterocolitis. We prefer to evert the colostomy as for the Brooke ileostomy, to allow the appropriate placement of appliances that protect the peristomal skin. Unfortunately, the incidence of distal prolapse of the colostomy is high,and increases proportionately with decreasing size of the baby. For the older infant and child, an initial definitive procedure can occasionally be performed. However, the objective is rarely achieved as there is usually a significant size discrepancy between the proximally dilated colon and the pelvis. A temporary diverting colostomy is usually indicated.

If a levelling colostomy is performed, definitive repair is accomplished between 2 and 6 months of age. This period allows enterocolitis to subside and the proximal colonic distension to lessen. Surgical repair performed before 6 months of age seems to provide the optimal functional outcome in infants: improved toilet training is seen compared to infants whose definitive surgery is delayed until they are 12 months of age.

The four major procedures used in North America and Europe in the treatment of Hirschsprung's disease are those described by Swenson, Duhamel, Soave, and Rehbein. The rectosigmoidectomy as recommended by Swenson has had the widest application in North America and has enjoyed considerable success. Nevertheless, disturbances of the lumbar parasympathetic chain may result from dissection in the pelvis and this had led to increased use of the Duhamel and Soave procedures. The Duhamel procedure, which limits the pelvic dissection to the retrorectal plane, places the ganglionic colon behind the rectum in the sacral hollow. With division of the intervening septum, the complication of faecal impaction in the aganglionic ventral pouch is averted. The Martin modification of the Duhamel procedure is often the procedure of choice in infants with total colonic aganglionosis. The Soave endorectal dissection, first advocated for children with familial polyposis and ulcerative colitis, takes place within the muscular rectal cuff and completely avoids injury to the filigrous lumbosacral complex. The normally innervated colon is then brought through the rectal cuff and is anastomosed to an area approximately 0.5 to 1.0 cm above the dentate line, preserving the fine continence afforded by anal sensation. The advocates of the Rehbein procedure dissect the anterior rectal cuff to within 2 cm of the anal verge but leave the posterior rectal wall undisturbed. A diagonal anastomosis is then performed between the distal rectum and the normally innervated proximal colon.

Regardless of the procedure performed, in a large, multi-institutional review, complications following definitive surgery included disturbances in micturition (3.6 per cent), enuresis (10.7 per cent), disruption of the anastomosis (2 per cent), and mild anal stenosis (5–14 per cent). Reoperation was required in 2 to 5 per cent of patients. However, 85 per cent of patients have satisfactory to excellent results, with normal sensations of rectal fullness, urgency, and an ability to discriminate flatus, liquid, and solid stool. The 15 per cent of patients in whom symptoms persist require aggressive re-evaluation, with rebiopsy to confirm that the transition zone is not involved at the site of the anastomosis and to eliminate the presence of other neuroenteric disorders, in particular neuronal intestinal dysplasia. In those instances, reoperation can result in significant improvement.

Most patients (75 per cent) have short-segment aganglionosis, limited to the rectosigmoid, in 14 per cent the disease involves the transverse and descending colon (long-segment disease), and a further 10 per cent of patients have total colonic or universal aganglionosis (Zuelzer-Wilson syndrome), for which treatment is suboptimal. If total colonic Hirschsprung's disease is encountered, the transition zone must be identified. Multiple biopsies to site the levelling ileostomy appropriately may be required. Because the ileum has diminished water absorptive capabilities even with adaptation, use of the right colon as a patch as proposed by Kimura or the left colon as a long anastomosis to the terminal ileum (the Martin procedure) has led to improved survival.

Ultrashort-segment Hirschsprung's disease is a disorder of the internal sphincter complex. While ganglion cells are found in the rectum, appropriate innervation may not be present at the level of the internal sphincter. Diagnosis of ultrashort-segment Hirschsprung's disease can only be made with manometry, which shows failure of the internal sphincter to relax, while normal ganglion cells are found above. Treatment is directed toward release of the internal sphincter with a sphincter myotomy.

Other disorders of the neuronal intestinal network are increasingly being recognized. In neuronal intestinal dysplasia, ganglion cells are present but are in an ectopic location; there is also hyperplasia of the submucosal and intermyenteric plexuses. Occasionally, hypertrophic nerve trunks and aberrant neurofibrils are identified by acetylcholinesterase stain in addition to these expansive plexuses. Children with neuronal intestinal dysplasia will most often present with a long-standing history of constipation, often dating from early infancy. It is estimated that 25 per cent of children with Hirschsprung's disease have concomitant neuronal intestinal dysplasia, which may explain why some patients continue to have symptoms following definitive surgery.

Boley SJ. New modification of the surgical treatment of Hirschsprung's disease. Surgery 1964; 56: 1015–7.

Duhamel B. A new operation for the treatment of Hirschsprung's disease. Arch Dis Child 1960; 178: 38–9.

Holschneider AM, ed. Hirschsprung's disease. New York: Thieme-Stratton, Inc, 1982.

Kimura K, Nishijima E, Muraji T, Tsugawa C, Matsutmo Y. Extensive aganglionosis: further experience with the colonic patch graft procedure and long-term results. J Pediatr Surg 1988; 23: 52–6.

Kleinhaus S, Boley SJ, Sheran M, Sieber WK. Hirschsprung's disease: a survey of the members of the surgical section of the American Academy of Pediatrics. J Pediatr Surg 1979; 14: 588–97.

Martin LW, Caudill DR. A method for the elimination of the blind rectal pouch in the Duhamel operation for Hirschsprung's disease. Surgery 1967; 62: 951–3.

Martin LW. Surgical management of Hirschsprung's disease involving the small intestine. Arch Surg 1968; 97: 183–9.

Schärli AF, Meier-Ruge PW. Localized and disseminated forms of neuronal intestinal dysplasia mimicking Hirschsprung's disease. J Pediatr Surg 1981; 16: 164–170.

Sieber WK. Hirschsprung's disease. Current Problems in Surgery 1978; 15: 1–93.

Soave F. A new surgical technique for treatment of Hirschsprung's disease. Surgery 1964; 56: 1007–14.

Swenson O, Bill AH. Resection of rectum and rectosigmoid with preservation of the sphincter for benign spastic lesions producing megacolon: an experimental study. Surgery 1948; 24: 212–20.