A comparison of injections of botulinum toxin and topical nitroglycerin ointment for the treatment of chronic anal fissure

Background and Methods Lateral internal sphincterotomy, the most common tre atment for chronic anal fissure, may cause permanent injury to the anal sph incter, which can lead to fecal incontinence, We compared two nonsurgical t reatments that avert the risk of fecal incontinence. We randomly assigned 5 0 adults with symptomatic chronic posterior anal fissures to receive treatm ent with either a total of 20 U of botulinum toxin injected into the intern al anal sphincter on each side of the anterior midline or 0.2 percent nitro glycerin ointment applied twice daily for six weeks. Results After two months, the fissures were healed in 24 of the 25 patients (96 percent) in the botulinum-toxin group and in 15 of the 25 (60 percent) in the nitroglycerin group (P=0.005). No patient in either group had fecal incontinence. At some time during treatment, five patients in the nitrogly cerin group had transient, moderate-to-severe headaches that were related t o treatment. None of the patients in the botulinum-toxin group reported adv erse effects, Ten patients who did not have a response to the assigned trea tment - 1 in the botulinum-toxin group and 9 in the nitroglycerin group - c rossed over to the other treatment; the fissures subsequently healed in all 10 patients. There were no relapses during an average of about 15 months o f follow-up. Conclusions Although treatment with either topical nitroglycerin or botulin um toxin is effective as an alternative to surgery for patients with chroni c anal fissure, botulinum toxin is the more effective nonsurgical treatment . (N Engl J Med 1999;341:65-9.) (C) 1999, Massachusetts Medical Society.