Chronic anal fissures treated with botulinum toxin injections: a dose-finding study with Dysport(®).

Botox(®) injection of the anal sphincter muscle cures chronic uncomplicated anal fissures in up to 80% of patients. This study examines the therapeutic efficacy and side effect profile of the British botulinum product Dysport(®) . Fifty patients (29 women) were recruited to participate in this randomized dose-finding study, their mean age being 32.9 years. The low dose group A was treated with a total dose of 20 U injected in two sites each lateral to the fissure, the high dose group B was treated with 40 U. Eighty-two percent of patients were pain-free within a week following the injections. The fissure was healed in 78% of treated patients after 3 months. Three patients relapsed within 6 months. The most common adverse side effect was transient incontinence (n = 4). Clinical outcome was not significantly different between the two treatment groups. The low dose can therefore be regarded sufficient for the treatment of anal fissure. Therapeutic efficacy was equivalent to published data on Botox treatment. Both Dysport(®) and Botox(®) can therefore be used to treat chronic uncomplicated anal fissures. Both Dysport(®) and Botox(®) therapy are well tolerated, can be performed on an out-patient basis and avoid the risk of permanent faecal incontinence which complicates surgical treatment of anal fissures.