PREDICTING LONG-TERM OUTCOME AFTER CLOSTRIDIUM BOTULINUM TOXIN INJECTION IN SYMPTOMATIC CHILDREN AFTER HIRSCHSPRUNG'S DISEASE CORRECTIVE SURGERY

Abstract

Background: The injection of Clostridium botulinum toxin (Botox) into the internal anal sphincter (IAS) in children with obstructive symptoms and/or enterocolitis after corrective surgery for Hirschsprung's disease (HD) is initially successful in 77%. However, predictors of long-term outcome after Botox are unknown. Aim: To determine which factors predict favorable long-term outcomes in symptomatic postoperative children with HD after initial Botox. Methods: A retrospective chart review of symptomatic postoperative children with HD that received Botox. Botox was usually given at the same time as rectal biopsies were performed to exclude aganglionosis. Long-term outcome was classified into four groups (excellent, good, fair, poor) based on continued symptoms, laxative usage, rectal therapies, or subsequent surgery. Excellent and good outcomes were considered favorable. Regression analyses using long term response as the outcome was performed. Results: 36 children received Botox, with a mean age of 5.3 ± 0.7 years and a follow-up of 32.9 ± 4.2 months. 29 (81%) had short segment disease and 4 (11%) total colonic HD. Past surgeries were Soave in 19 (53%), Duhamel in 9 (25%), Swenson in 5 (14%), and unknown type in 3 (8%). 16 (44%) had enterocolitis. During evaluation 7 (19%) were found to have persistent aganglionosis. 22 (61%) had multiple injections. A favorable long-term outcome was found in 15 (42%). After multivariate analysis, persistent aganglionosis predicted a poor long-term outcome (P < 0.05) with 6 (85.7%) doing poorly. Improvement after initial Botox occurred in 14 (93%) of those with a favorable long term outcome, and strongly predicted for this (P < 0.05). Other factors, including age, type of surgery, and extent of aganglionosis, were not significant predictors. Conclusions: An initial improvement after Botox is the strongest predictor of a favorable long-term outcome in children with HD after corrective surgery. Those with persistent aganglionosis are unlikely to benefit.