Randomized clinical trial comparing botulinum toxin injections with 0.2 per cent nitroglycerin ointment for chronic anal fissure

BACKGROUND: In recent years treatment of chronic anal fissure has shifted from surgical to medical. This study compared the ability of two non-surgical treatments-botulinum toxin injections and nitroglycerin ointment-to induce healing in patients with idiopathic anal fissure. METHODS: One hundred adults were assigned randomly to receive treatment with either type A botulinum toxin (30 units Botox or 90 units Dysport) injected into the internal anal sphincter or 0.2 per cent nitroglycerin ointment applied three times daily for 8 weeks. RESULTS: After 2 months, the fissures were healed in 46 (92 per cent) of 50 patients in the botulinum toxin group and in 35 (70 per cent) of 50 in the nitroglycerin group (P=0.009). Three patients in the botulinum toxin group and 17 in the nitroglycerin group reported adverse effects (P<0.001). Those treated with botulinum toxin had mild incontinence to flatus that lasted 3 weeks after treatment but disappeared spontaneously, whereas nitroglycerin treatment was associated with transient, moderate-to-severe headaches. Nineteen patients who did not have a response to the assigned treatment crossed over to the other therapy. CONCLUSION: Although treatment with either topical nitroglycerin or botulinum toxin is effective as an alternative to surgery for patients with chronic anal fissure, botulinum toxin is the more effective option.