Randomized, prospective trial comparing 0.2 percent isosorbide dinitrate ointment with sphincterotomy in treatment of chronic anal fissure: A two-year follow-up

PURPOSE: The aim of this trial was to compare lateral internal sphincterotomy with local 0.2 percent isosorbide dinitrate in the treatment of chronic anal fissure to minimize surgical complications such as minor fecal incontinence. METHODS: Fifty-four patients with chronic anal fissure were randomized in a prospective trial to either sphincterotomy or local 0.2 percent isosorbide dinitrate. All patients had anal function tests before and 5 weeks after treatment. RESULTS: In the ointment group, 18 patients (67 percent) healed at 5 weeks and 24 (89 percent) healed at 10 weeks of treatment. Maximum resting anal pressure was reduced 30 percent. Eight patients (30 percent) had minor side effects. In the surgical group, 26 patients (96 percent) healed at 5 weeks and 100 percent healed at 10 weeks after treatment, with 33 percent reduction in maximum resting anal pressure. Forty-four percent of patients had minor fecal incontinence, which remained in 15 percent after 24 months follow-tip. No statistical difference in maximum resting anal pressure was found between groups (P = 0.16), but the percentage of healing at 5 weeks was greater in the surgical group (P < 0.001). CONCLUSIONS: Isosorbide dinitrate ointment must be considered as the first choice of treatment in patients with chronic anal fissure. Surgery should be indicated if chemical sphincterotomy fails.