Assessment of the colon innervation with serial biopsies above the aganglionic zone before the pull-through procedure in Hirschsprung's disease

Different types of colonic dysganglionosis, and in particular intestinal neuronal dysplasia (IND) have been blamed for certain postoperative complications after surgery for Hirschsprung's disease (HD). We prospectively assessed colon innervation above the aganglionic zone (AZ) before proceeding to pull-through (PT) in order to rule-out IND as a cause of those complications. We first used a two-stage procedure (TSP): Full-thickness biopsies were harvested above the AZ and a colostomy was established during a first stage. Biopsies were assessed postoperatively with conventional acetyl-cholinesterase (AChE) histochemistry and immunohistochemistry for protein gene product 9.5 (PGP 9.5) and antigen CD56 (CD56). Biopsies were repeated after 6 months if IND was found. When the innervation was normal, the PT was performed during a second stage. Since having refined a rapid AChE reaction, we now use a single-stage procedure (SSP). Biopsies are harvested above the AZ and assessed intraoperatively with rapid AChE staining, proceeding to PT during the same stage when the innervation is normal. Four patients underwent the TSP; 3 had normal innervation above the AZ and subsequently underwent PT. In 1 patient serial biopsies revealed IND-like dysganglionosis; 9 months later, the innervation was normal in repeat biopsies and PT was undertaken. Eleven patients underwent the SSP. Biopsies were normal in 9 but showed unclassifiable forms of dysganglionosis in 2. As these changes were not typical for IND, all patients underwent PT in the same stage. Both patients had a poor outcome of bowel function that required a colostomy in I and daily saline irrigations in the other. IND was found in repeat biopsies made during the colostomy in the Ist patient and markedly hypertrophied nerves in the submucosa as well as ectopic nerve cells in the lamina propria in the proximal border of the pulled-through colon in the other. All 13 other patients have normal bowel function. The assessment of colon innervation above the AZ before proceeding to PT allows safer surgical treatment of HD. Intraoperative AChE staining is reliable, but due to the size and number of the biopsies, IND might be overlooked. Non classifiable dysganglionosis should thus be taken into account in the diagnosis and follow-up of the patients, as it may be clinically significant.