Long-term clinical outcome after botulinum toxin injection in children with nonrelaxing internal anal sphincter.

Abstract

Children with surgically repaired Hirschsprung's disease (HD) and those with internal anal sphincter (IAS) achalasia may develop obstructive gastrointestinal symptoms and/or enterocolitis due to a functional obstruction caused by an inability of the IAS to relax. Anal sphincter Clostridium botulinum toxin (BoTox) injections may provide a reversible therapy. However, there is limited information regarding the long-term outcomes of children receiving this therapy. The primary aim of this study was to determine the long-term clinical outcomes of BoTox therapy in children with a nonrelaxing IAS. The secondary aim of this study was to determine prognostic factors predicting a favorable outcome following BoTox IAS injection. We conducted a retrospective review of children with nonrelaxing IAS who received anal sphincter BoTox at a tertiary medical center. Children were classified into one of four long-term clinical outcome groups (excellent, good, fair, poor). A total of 73 children (30 HD, 43 IAS achalasia) received anal sphincter BoTox injections and had a mean follow-up of 32.1+/-2.9 (s.e.) months. A mean of 2.7+/-0.2 injections were given to each child, with 56 (76.7%) children receiving multiple injections. An initial clinical improvement was seen in 65 of 73 (89%) children after the first injection. A total of 39 (53.4%) children had an excellent or good long-term outcome that was maintained for a mean of 17.1+/-3.1 months from the time of the last BoTox injection. Hospitalization rates significantly decreased in those previously hospitalized before initial BoTox injection. Seven (9.5%) patients developed transient fecal incontinence, and one (1.3%) developed significant pain after an injection. Factors predicting a favorable long-term clinical outcome were initial short-term improvement after the first BoTox injection and having IAS achalasia rather than HD. Anal sphincter BoTox may be an effective and safe long-term therapy for children with nonrelaxing IAS.