Botulinum toxin for the treatment of anal fissure

BACKGROUND: The classic treatment for uncomplicated anal fissure is surgical sphincterotomy, i.e. cutting of the internal anal sphincter, thus eliminating spasm of this muscle and breaking the vicious circle of pain, spasm and inflammation. Recently, however, botulinum toxin has become available for the treatment of muscular dystonias, and thus for anal fissure. In the present study, we investigated the effectiveness of treatment with botulinum toxin in 76 patients with uncomplicated anal fissure. MATERIAL AND METHOD: The 76 patients received an injection of 40 U of botulinum toxin on each side of the fissure. Response was monitored 7, 30 and 90 days later. All patients who did not show clear improvement after 30 days received a second dose of 40 U on each side. RESULTS: After 90 days, 51 patients (67%) showed complete recovery, 19 patients (25%) substantial improvement though not complete recovery, and 6 patients (8%) no significant improvement. Transitory gas incontinence was reported by 2 patients (2.6%), and 1 patient presented hemorrhoidal thrombosis. DISCUSSION: Botulinum toxin enables chemical denervation of the internal sphincter, facilitating healing of the anal fissure. Its principal advantages with respect to surgical sphincterotomy are the absence of the general risks of surgery, and reduced incidence of incontinence, which even if it occurs tends to be transitory. The technique does not require hospitalization and is well tolerated. It appears suitable for the initial treatment of uncomplicated anal fissure, reserving surgical treatment for those cases which fail to response adequately.