Internal sphincterotomy is superior to topical nitroglycerin in the treatment of chronic anal fissure - Results of a randomized, controlled trial by the Canadian Colorectal Surgical Trials Group

PURPOSE: This was a multicenter, randomized, controlled trial to compare th e effectiveness of topical nitroglycerin with internal sphincterotomy in th e treatment of chronic anal fissure. METHODS: Patients with symptomatic chr onic anal fissures were randomly assigned to 0.25 percent nitroglycerin tin or internal sphincterotomy. Both groups received stool softeners and fiber supplements and were assessed at six weeks and six months. RESULTS: Ninety patients were accrued, but 8 were excluded from the analysis because they refused internal sphincterotomy after randomization (6), the fissure healed before surgery (1), or a fissure was not observed at surgery (1). There we re 38 patients in the internal sphincterotomy group (22 males; mean age, 40 .3 years) and 44 patients in the nitroglycerin group (15 males; mean age, 3 8.7 years). At six weeks 34 patients (89.5 percent) in the internal sphinct erotomy group compared with 13 patients (29.5 percent) in the nitroglycerin group had complete healing of the fissure (P = 5 x 10(-8)). Five of the 13 patients in the nitroglycerin group relapsed, whereas none in the internal sphincterotomy group did. At six months fissures in 35 (92.1 percent) pati ents in the internal sphincterotomy group compared with 12 (27.2 percent) p atients in the nitroglycerin group had healed (P = 3 x 10(-9)). One (2.6 pe rcent) patient in the internal sphincterotomy group required further surger y for a superficial fistula compared with 20 (45.4 percent) patients in the nitroglycerin group who required an internal sphincterotomy (P = 9 x 10(-6 )). Eleven (28.9 percent) patients in the internal sphincterotomy group dev eloped side effects compared with 37 (84 percent) patients in the nitroglyc erin group (P < 0.0001), Nine (20.5 percent) patients discontinued the nitr oglycerin because of headaches (8) or a severe syncopal attack (1). CONCLUS IONS: Internal sphincterotomy is superior to topical nitroglycerin 0.25 per cent in the treatment of chronic anal fissure, with a high rate of healing, few side effects, and low risk of early incontinence. Thus, internal sphin cterotomy remains the treatment of choice for chronic anal fissure.