24- hirschsprung disease

1-Hirschsprung disease is a developmental disorder of the enteric nervous system and is

characterized by an absence of ganglion cells in the distal colon resulting in a functional obstruction.

2-Most cases are now diagnosed in the newborn period. Hirschsprung disease should be considered in any newborn who fails to pass meconium within 24-48 hours after birth. Although contrast enema is useful in establishing the diagnosis, full-thickness rectal biopsy remains the criterion standard. Once the diagnosis is confirmed, the basic treatment is to remove the poorly functioning aganglionic bowel and create an anastomosis to the distal rectum with the healthy innervated bowel (with or without an initial diversion).

3-Hirschsprung disease should be considered in any newborn with delayed passage of meconium or in any child with a history of chronic constipation since birth. Other symptoms include bowel obstruction with bilious vomiting, abdominal distention, poor feeding, and failure to thrive.

4-Surgical management of Hirschsprung disease begins with the initial diagnosis, which often requires a full-thickness rectal biopsy. Traditionally, treatment also includes creating a diverting colostomy at the time of diagnosis, and, once the child grows and weighs more than 10 kg, the definitive repair is performed.

This standard of treatment was developed in the 1950s after reports of relatively high leak and stricture rates with the single stage procedure were initially described by Swenson. However, with the advent of safer anesthesia and more advanced hemodynamic monitoring, a primary pull-through procedure without a diverting colostomy is increasingly being performed. Contraindications to a one-stage procedure include massively dilated proximal bowel, severe enterocolitis, perforation, malnutrition, and inability to accurately determine the transition zone by frozen section.

For neonates who are first treated with a diverting colostomy, the transition zone is identified and the colostomy is placed proximal to this area. The presence of ganglion cells at the colostomy site must be unequivocally confirmed by a frozen-section biopsy. Either a loop or end stoma is appropriate, usually based on the surgeon's preference.

A number of definitive procedures have been used, all of which have demonstrated excellent results in experienced hands. The 3 most commonly performed repairs are the Swenson, Duhamel, and Soave procedures. Regardless of the pull-through procedure chosen, cleaning the colon prior to definitive repair is necessary.

• Swenson procedure

• The Swenson procedure was the original pull-through procedure used to treat Hirschsprung disease.
• The aganglionic segment is resected down to the sigmoid colon and the remaining rectum, and an oblique anastomosis is performed between the normal colon and the low rectum.

• Duhamel procedure

• The Duhamel procedure was first described in 1956 as a modification to the Swenson procedure.
• Key points are that a retrorectal approach is used and a significant portion of aganglionic rectum is retained.
• The aganglionic bowel is resected down to the rectum, and the rectum is oversewn. The proximal bowel is then brought through the retrorectal space (between the rectum and sacrum), and an end-to-side anastomosis is performed on the remaining rectum.

• Soave (endorectal) procedure

• The Soave procedure was introduced in the 1960s and consists of removing the mucosa and submucosa of the rectum and pulling the ganglionic bowel through the aganglionic muscular cuff of the rectum.
• The original operation did not include a formal anastomosis, relying on scar tissue formation between the pull-through segment and the surrounding aganglionic bowel. The procedure has since been modified by Boley to include a primary anastomosis at the anus.

• Anorectal myomectomy

• For children (and occasionally adults) with ultrashort-segment Hirschsprung disease, removing a strip of posterior midline rectal wall is an alternative surgical option.
• The procedure removes a 1-cm wide strip of extramucosal rectal wall beginning immediately proximal to the dentate line and extending to the normal ganglionic rectum proximally.
• The mucosa and submucosa are preserved and closed.

• Procedures for long-segment Hirschsprung disease
  • Patients with total colonic involvement require modified procedures to bypass the aganglionic colon yet preserve the absorptive surface area and allow for proper growth and nutritional support.
  • Most procedures include a side-to-side anastomosis of the ganglionic/propulsive small bowel to a short segment of the aganglionic/absorptive colon.
  • Whether a short right colonic patch or a small bowel-to-rectal wall Duhamel anastomosis is created is perhaps less important than maintaining a short patch length (<10>
  • Long-segment anastomoses, such as the Martin procedure, are no longer advocated.

• A laparoscopic approach to the surgical treatment of Hirschsprung disease was first described in 1999 by Georgeson. The transition zone is first identified laparoscopically, followed by mobilization of the rectum below the peritoneal reflection. A transanal mucosal dissection is performed, followed by prolapsing of the rectum through the anus and anastomosis. Functional outcomes appear to be equivalent to open techniques based on short-term results (Georgeson, 1999; de Lagausie, 1999; Curran, 1996).
• Transanal pull-through in which no intra-abdominal dissection is performed has also been described (Langer, 1999; De La Torre-Mondregan, 1998). The entire procedure is performed from below in a manner similar to perineal rectosigmoidectomy. The transition zone is identified and anastomosis is performed. Similar to the laparoscopic approach, outcomes have been similar to open single stage approaches with the benefits of minimal analgesia and shortened hospital stays (Langer, 2000; De La Torre, 2000; Langer, 2003).
• ---------------------------------------------