Randomized clinical trial Randomized clinical trial comparing botulinum toxin injections with 0·2 per cent nitroglycerin ointment for chronic anal fissure G. Brisinda, F. Cadeddu, F. Brandara, G. Marniga and G. Maria Department of Surgery, Catholic University Hospital Agostino Gemelli, Istituto di Clinica Chirurgica Generale, Policlinico Universitario Agostino Gemelli, Largo Agostino Gemelli 8, 00168 Rome, Italy Correspondence to: Dr G. Brisinda (e-mail: gbrisin@tin.it) 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. Paper accepted 8 January 2007 Published online in Wiley InterScience (www.bjs.co.uk). DOI: 10.1002/bjs.5514 Introduction Anal fissure, a split in the skin of the distal anal canal, is a common problem that causes substantial morbidity in people who are otherwise healthy 1 . The incidence of anal fissure is similar in men and women. Most fissures occur in the posterior midline of the anal canal 2 ; multiple fissures or lateral fissures may have other causes, such as Crohn’s disease, ulcerative colitis, tuberculosis, or infection with human immunodeficiency virus or syphilis 2,3 . Chronic anal fissure is usually associated with spasm of the internal anal sphincter, relief of which is central to fissure healing 4,5 . Since 1951, the most common treatment for chronic anal fissure in the USA and Europe has been lateral internal sphincterotomy, as described by Eisenhammer 6 , and this remains the ‘gold standard’ for treatment of anal fissure 7,8 . Although Eisenhammer’s technique is simple and effective, the fundamental drawback of this operation is its potential to cause minor but sometimes permanent alterations in the control of gas, mucus and, occasionally, stool. Traditional surgery permanently weakens the internal anal sphincter, and incontinence after internal sphincterotomy is not insignificant 9 . Whether an open or closed technique is used does not seem to influence incontinence rates 1,10–12 . Caution must be exercised when contemplating internal sphincterotomy, particularly in elderly patients or those with diarrhoea, irritable bowel syndrome, diabetes, or recurrent fissure after previous surgery 13 . Furthermore, with the ready availability of medical therapy, the risk of a first-line surgical approach is difficult to justify 1 . Treatment of chronic anal fissure has shifted in recent years from surgical to medical. Primary medical therapy is an inexpensive and convenient way of curing most chronic anal fissures 1 . With medication, it is possible to create the effect of a temporary or reversible sphincterotomy, reducing anal sphincter pressure only until the fissure has healed. Two such approaches – injection of botulinum toxin and application of nitroglycerin ointment – have been Copyright  2007 British Journal of Surgery Society Ltd British Journal of Surgery 2007; 94: 162–167 Published by John Wiley & Sons Ltd Downloaded from https://academic.oup.com/bjs/article/94/2/162/6142586 by guest on 01 January 2024