Role of rectal biopsy in predicting response to intrasphincteric botulinum toxin injection for obstructive symptoms after a pullthrough operation.

OBJECTIVE Our aim was to correlate the pathological results and clinical response in patients who underwent botulinum toxin (BT) injection for obstructive symptoms (OS) after a pullthrough operation for Hirschsprung's disease (HD). METHODS Between August 2002 and February 2006, 16 of 107 HD patients (15%) were referred with persistent OS after pull-through (PT) operation in this center. They underwent rectal biopsy and BT injection in the internal sphincter. Their responses to BT injection were evaluated by the constipation score before, and at 1, 3 and 8 months after the injection, and anorectal manometry (ARM) before and at 2 weeks, and 1 and 8 months after the injection. The association between response to BT and acetylcholinesterase (AChE) staining of rectal biopsy was also assessed. RESULTS Fourteen of 16 patients (87%) had improvement in bowel function after 2 weeks, and two patients did not respond at all. Six of the 14 patients with early response had recurrence of symptoms after 2-3 months. Eight patients with normal ganglia and negative AChE had good response with no recurrence on follow-up. However, 4 of 6 recurrences were neurogenic dysfunctions and 2 were intestinal neuronal dysplasia (2-4+AChE). Two patients with no response had an aganglionic segment (4+AChE). Four of 6 patients with recurrence showed improvement with BT re-injection and only 2 did not improve. CONCLUSION A higher degree of AChE staining is associated with lack of response to BT injection. This is also a test for predicting the severity of neurogenic dysfunction in the intestinal wall.