Important colic distension (red arrows) on the x-ray with lack of air in the recto-sigma x
The barium contrast enema is simple and exhaustive in the case of evident transition zone (“funnel” aspect) between the two segments (the narrow aganglionic distal segment and the proximal dilated one) (Fig. 22.2). Another finding that is suggestive for HD is the retention of contrast in the colon on a 24-h post-evacuation film. In case of total colic aganglia, it is characteristic the presence of the microcolon associated with massive ileal reflux of contrast mean.
Barium contrast enema showing a distal narrow aganglionic segment (yellow arrow) and a proximal dilated segment (red arrow)
Anorectal manometry in affected patients shows the presence of a high-pressure rectal baseline reflex at rest and the absence of the recto-anal inhibitory reflex (RAIR).
Physiologically there is a reflex relaxation of the internal anal sphincter in response to recto-anal inhibitory reflex (RAIR). In patients with HD, the rectal baseline pressure is higher than normal, and the recto-anal inhibitory reflex is absent (negative RAIR). This technique has yielded good results when used in children, but it is not widely available for neonates.
The rectal biopsy (full-thickness biopsy) directly demonstrates the absence of ganglion cells in the myenteric plexus and the presence of cholinergic AChE-positive fibers in the hypertrophic submucosa. It is the most sensitive and specific investigation for the diagnosis of HD but also the most invasive because it requires a surgical procedure (Fig. 22.3). The suction biopsy was introduced in order to reduce this invasiveness. The procedure does not involve the colonic mucosa incision, as it is unnecessary for the diagnosis. The rectal suction biopsy with the immunochemical demonstration of acetylcholinesterase has become the gold standard for the diagnosis of HD. The procedure can be performed in an outpatient clinic. The rectal suction biopsy (RSB) is performed with the transanal Noblett clamp. Three samples are taken from 2 to 5 cm above the dentate line, and all samples must include a fragment of submucosa. The samples are taken at different points of the rectal circumference (“3, 6, and 9 h”).
Laparoscopic-assisted biopsy. The intestinal segment is chosen and exteriorized through the umbilical wound (a). The biopsy is performed outside the abdomen (b, c). Laparoscopic control at the end of the procedure (d)
The immunochemical diagnosis is based on the HD physiopathology. In recto-colic aganglionic segments, there is a significant increment of the parasympathetic cholinergic elements from the sacrum. The cholinergic fibers in AChE-positive patient with HD are thick and intricate nervous trunks that cross the muscularis mucosa and as hypertrophied nerves in the submucosa. The immunochemical examination looks for the increment in cholinergic AChE-positive fibers in the submucosa.
When there is a clinical suspicion of HD, the first therapeutic measure consists of performing rectal stimulations or irrigations in order to keep the colon clean and decompressed and avoid the onset of HAEC.
The irrigations are performed with physiological solution (approximately 10–20 cm3/kg) to be repeated two to three times a day. Once the diagnosis is confirmed, the surgical timing depends on the patient’s age. The majority of the diagnosis is performed in newborns, and the operation is planned between 2 and 4 months of life. In older patients, surgery is performed once the diagnosis has been confirmed. The “one-stage” correction has emerged as the procedure of choice, thanks to the proven effectiveness of the “conservative bowel management” and the proven benefits of a neonatal intervention, reducing the role of the colostomy that today remains indicated for total colonic aganglia (ileostomy) and recurrent HAEC.
There are numerous surgical techniques described for the treatment of HD. The goals of surgery are the removal of the aganglionic bowel and the lowering (pull-through) of the normally innervated intestinal tract down to the anus, preserving the sphincter function.
The most commonly performed, and therefore considered “the major pull-through procedures,” are:
Duhamel retrorectal transanal pull-through
Rehbein pull-through with anterior colorectal anastomosis
Soave rectosigmoidectomy with aseptic endorectal colon pull-through
The Swenson procedure consists of removing the entire aganglionic colon and performing an end-to-end anastomosis above the anal sphincter after the perineal eversion of the aganglionic rectum. The procedure is associated with high risk of injuring the pelvic nerves, vessels, and other pelvic structures.
The Duhamel technique provides for the creation of a retrorectal pull-through (between the rectum and the sacrum) with subsequent anastomosis between the normally innervated bowel (posterior) and the aganglionic segment (anterior). Although the less pelvic dissection makes the procedure safer, there can be problems related to the persistence of aganglionic segments.
The Soave technique is largely used, thanks to the effectiveness and safety of the endorectal dissection. The technique involves an abdominal and a perineal step.
The abdominal step classically requires a laparotomy (left pararectal or sovrapubic incision according to Pfannenstiel) to access the abdominal cavity. The procedure starts from the determination of the distal normally ganglionic segment: the region is visually identified above the transition zone (“funnel zone”) and confirmed performing a seromuscular biopsy in the colon next to the suspected transition zone. The sample is sent for histological examination. The mesocolon of the aganglionic segment (distal to the intestinal biopsy) is dissected once the presence of ganglia has been confirmed. Then the seromuscular layer is circumferentially separated from the rectal mucosa.
The perineal step provides for the transanal eversion of the rectal mucosal cylinder maintaining the seromuscular layer inside the pelvis. In other words, the pull-through bowel is lowered within a “cuff” made of aganglionic muscle. Once the everted mucosa has been resected, the aganglionic colon is lowered outside the perineum until the normally ganglionic region is reached. The aganglionic colon is removed, and the remaining mucosa of the colon is anastomosed with the residual anal mucosa.
At the end of the pull-through, the neorectum consists of a double muscular layer. The outer shell is the rectal native musculature (“cuff”) located in anatomical continuity with the external sphincter, responsible for the physiological continence mechanisms. The internal muscular layer is represented by the musculature of the lowered normally ganglionic bowel whose function is to ensure the normal fecal progression.
In recent years, the evolution in the treatment of HD has permitted the use of laparoscopic surgery that gained acceptance becoming the technique of choice for the treatment of almost all type of HD.
In 1995, Keith E. Georgeson described “the primary laparoscopic-assisted transanal endorectal colon pull-through for Hirschsprung’s disease.” The procedure described by Georgeson may be defined as a “minimally invasive Soave-type operation” because it is based on the same surgical principles of the Soave technique with few differences: the section of the mesocolon is performed laparoscopically and the endorectal dissection is completed through the anus (transanal) and not through the abdominal cavity.
The technique has a first laparoscopic step and a subsequent perineal step. The laparoscopic step starts with the identification of the transition zone (by laparoscopic biopsy). Once the presence of ganglia has been confirmed, the mesocolon of the distal aganglionic bowel is dissected until you reach the peritoneal rectal reflection (Fig. 22.4).
Laparoscopic mesocolon dissection of the aganglionic bowel, performed distally to the biopsy
The rectum is then dissected starting from the circumferential section of the peritoneal reflection. The rectal isolation proceeds with blunt dissection adjacent to the rectal walls (Fig. 22.5).
Section of the rectal peritoneal reflection
The perineal step involves the dissection of the rectal mucosa and the subsequent pull-through of the colon. The transanal mucosal rectal dissection starts with a mucosal incision performed 0.5–1 cm above the dentate line (Fig. 22.6).
Circumferential mucosal incision, 5–10 mm above the pectinate line
The blunt approach permits the identification of a submucosal plane of dissection (Fig. 22.7). The mucosectomy proceeds proximally for 10–15 cm until the plane of the rectal dissection (performed laparoscopically) has been reached. At this point, the rectum “prolapses” outside.
A submucosal dissection plane is identified by blunt dissection (m anal mucosa with traction stitches, M muscular cuff)
The rectal muscular layer (“cuff”) is sectioned at its distal part, and it is reintroduced into the pelvis after the section of the anterior and posterior edges (Fig. 22.8).
Mucosectomy proceeds until the rectum prolapses (once the point of the laparoscopic isolation has been reached). The rectal muscular wall without the mucosa is sectioned and reintroduced into the pelvis (m mucosa, M muscle, C muscular cuff)
The next step is the lowering of the colon inside the rectal muscular cuff until the normally ganglionic region (where there the biopsy was performed) is identified (Fig. 22.9).
Pull-through of the aganglionic colon inside the muscular cuff until the site of the biopsy (yellow arrow) is reached
22.11 Postoperative Care
A nasogastric tube is maintained for 12–24 h. The patient continues broad-spectrum antibiotic therapy for 5–7 days. The patient can be fed once bowel movements resume and discharged once full fed is reached. Two weeks after surgery, the anal anastomosis is dilated to avoid strictures. Anal dilatations continue for about 1 year.
The most frequent early postoperative complication is represented by colo-anal anastomosis dehiscence (3.2 %) which, if not massive, is solvable conservatively.
Late postoperative complications are more frequent:
HAEC (2–40 %) treated by intensive bowel irrigations, broad-spectrum antibiotics, and, in severe unresponsive cases, packaging colostomy.
Colo-anal anastomosis stenosis (0–20 %): a risk factor in the onset of a stenosis is its previous dehiscence; conservative treatment with anal dilatation is usually sufficient to resolve the stenosis.
22.13 Redo Pull-Through for Hirschsprung’s Disease
Härold Hirschsprung first described congenital aganglionosis and the associated clinical features in 1886. While Swenson is credited for the first successful treatment of Hirschsprung’s disease (HD)  in 1948, there are descriptions of the disease process dating back several centuries . Over the last 65 years, many modifications to the surgical repair of HD have been proposed. The operative principles remain the same in that the aganglionic bowel is resected and healthy, and ganglionated bowel is sutured or stapled low in the anal canal above the dentate line, known as a pull-through (PT). The most common techniques performed today are a transanal approach with or without laparoscopic assistance, a modified endorectal PT, and a Duhamel retrorectal PT.
Regardless of the technique, repair most often leads to satisfactory results. However, some children experience long-term postoperative complications . These problems can present with a wide array of stooling disorders after an apparent successful PT procedure. These disorders can range from intermittent enterocolitis to far more significant issues such as severe stool retention, intestinal obstruction, as well as incontinence . Many of these disorders can be managed medically or may even be self-limiting, but on rare occasions (<3 % of children from our own group of primary-PT cases), the child may require a redo-PT procedure.
22.13.2 Redo Pull-Through Data
There is a lack of data with respect to outcomes following redo PT for HD, and while studies have suggested that approach is superior, there is no consensus as to which is the superior approach [8–10]. Specific gaps in data include indications and timing for redo-PT surgery, surgical procedure for redo PT, and stooling outcomes. The University of Michigan recently published their experience over 40 years with PTs for Hirschsprung’s disease, including 467 primary pull-through procedures . Nine (2 %) of these eventually underwent redo PT. An additional 37 patients were referred after primary PT elsewhere required redo PT for a total of 46 individuals (52 % male) who underwent redo PT. Since that publication, five additional redo-PT cases have been performed. The child’s primary PT was performed for varying levels of aganglionosis, with 59 % having rectosigmoid, 13 % left-sided, and 9 % mid-colon or right-sided (including one patient with total colonic) disease. For 19 % of patients, no recorded length of involved aganglionosis was documented. Open endorectal PT (ERPT) was the most frequent primary PT (41 %), followed by transanal ERPT (22 %), Swenson (17 %), Duhamel (11 %), and unknown operation (9 %).
22.214.171.124 Outcomes After Primary Pull-Through
Common and serious long-term complications after definitive treatment for HD are divided into three groups. These include soiling/incontinence, persistent problems with the passage of stool (e.g., constipation), and recurrent Hirschsprung-associated enterocolitis (HAEC) . Factors contributing to these problems are either pathologic or anatomic. Pathologic causes comprise residual aganglionosis or transitional zone pathology. The anatomic causes involve stricture, with or without anastomotic leak, retained dilated segment, obstructing Duhamel pouch/Soave cuff, or twisted pull-through.
The complications were similar in the Michigan review of redo-PT patients. Early complications after the patient’s primary PT occurred in 44 % of all cases that eventually underwent a redo PT. This rate was higher than a historical cohort of patients not requiring a redo PT (16 % P = 0.01) . These early complications included anastomotic leak (19 %), obstruction (9 %), twisted PT (4 %), and enterocolitis (6 %). Late complications in those children eventually requiring a redo PT included obstructive symptoms (87 %) of which functional constipation made up the majority (54 %). Obstruction was caused by stricture in 22%, and 9 % had a specific technical cause for constipation, including obstructing Duhamel pouch (n = 3) and a twisted PT segment (n = 1).