[Treatment of anal fissures with botulinum toxin].

Chronic anal fissure is a common proctological disease. Botulinum toxin (BTX) can be used for temporary chemical denervation. The administration is by intramuscular injections into either the external or the internal anal sphincter muscles. The mode of action, administration techniques and possible complications or adverse effects of BTX therapy are discussed. The healing rate is dependent on the BTX dosage. The short-term healing rate (< or = 6 months) is between 60 and 90 %. In long-term follow-up studies (> 1 year), about 50 % of patients show a complete response. Adverse effects are generally mild but relapses occur more often compared to surgery. Conservative therapies including BTX are currently considered mostly as the first-line treatment. Among the surgical procedures, lateral sphincterotomy is the most effective treatment but shows higher incontinence and general morbidity rates than BTX.