Botulinum toxin for the treatment of chronic constipation in children with internal anal sphincter dysfunction.

Internal anal sphincter (IAS) dysfunction is a cause of refractory constipation in children. The goal of this study was to determine whether intrasphincteric injection of botulinum toxin is effective in the treatment of constipation in pediatric patients with IAS dysfunction. A retrospective review was performed of 24 pediatric patients with intractable constipation. All patients had abnormal anorectal manometry, with either elevated IAS resting pressure (> or =100 mm Hg) or an absent or diminished rectoanal inhibitory reflex. Patients with Hirschsprung's disease were excluded. All patients underwent botox injection into the IAS and were followed for a minimum of 6 months. Of 24 patients, 22 experienced significant improvement in their constipation lasting greater than 2 weeks. The duration of effect was variable, with 12 patients demonstrating benefit lasting at least 6 months. Transient postoperative incontinence occurred in five patients. Intrasphincteric injection of botox is a safe and effective treatment for intractable constipation in children with IAS dysfunction.