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

Abstract

Purpose: This was a multicenter, randomized, controlled trial to compare the effectiveness of topical nitroglycerin with internal sphincterotomy in the treatment of chronic anal fissure.

Methods: Patients with symptomatic chronic anal fissures were randomly assigned to 0.25 percent nitroglycerin tid 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 were 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, 38.7 years). At six weeks 34 patients (89.5 percent) in the internal sphincterotomy group compared with 13 patients (29.5 percent) in the nitroglycerin group had complete healing of the fissure (P = 5x10(-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) patients in the internal sphincterotomy group compared with 12 (27.2 percent) patients in the nitroglycerin group had healed (P = 3x10(-9)). One (2.6 percent) patient in the internal sphincterotomy group required further surgery for a superficial fistula compared with 20 (45.4 percent) patients in the nitroglycerin group who required an internal sphincterotomy (P = 9x10(-6)). Eleven (28.9 percent) patients in the internal sphincterotomy group developed side effects compared with 37 (84 percent) patients in the nitroglycerin group (P<0.0001). Nine (20.5 percent) patients discontinued the nitroglycerin because of headaches (8) or a severe syncopal attack (1).

Conclusions: Internal sphincterotomy is superior to topical nitroglycerin 0.25 percent in the treatment of chronic anal fissure, with a high rate of healing, few side effects, and low risk of early incontinence. Thus, internal sphincterotomy remains the treatment of choice for chronic anal fissure.