Botulinum toxin versus other therapies for treatment of chronic anal fissure

Anal fissure is the most frequent of proctological pathology after hemorrhoids. The hypertonicity of the internal sphincter and the hypovascularization of the posterior pole of the anus play a central role in its pathophysiology. Treatment aims to reduce the hypertonicity of the internal sphincter, thus eliminating pain, allowing healing, and avoiding recurrence. Treatment of acute anal fissure is essentially medical; treatment of chronic anal fissure resistant to therapy is surgical. The reference surgical treatments are lateral internal sphincterotomy (LIS), regardless of its risk for flatus incontinence, and posterior sphincterotomy with anoplasty. Conservative approaches such as topical application of ointment or botulinum toxin injections have been proposed in order to treat this condition without any risk of permanent injury to the internal anal sphincter. These treatments are effective in a large number of patients. Furthermore, with the availability of medical therapies to induce healing of anal fissure, the risk of a first-line surgical approach is difficult to justify. The conservative treatments have a lower cost than surgery. This paper reports the most recent findings on conservative treatment of chronic anal fissure.