Reasons for failure of glyceryl trinitrate treatment of chronic fissure-in-ano: a multivariate analysis.

PURPOSE: Although glyceryl trinitrate ointment has become the first-line treatment for chronic anal fissure, healing rates are lower than after lateral internal sphincterotomy. The purpose of this study was to identify which factors are associated with treatment failure of glyceryl trinitrate ointment.
METHODS: All patients who presented with chronic anal fissure from March 1997 to November 1998 were treated with 0.2 percent glyceryl trinitrate ointment. They were prospectively evaluated until healing or lateral internal sphincterotomy occurred, and long-term follow-up was obtained by standardized telephone questionnaire. A Cox model multivariate analysis was used with seven variables to determine significant factors related to healing.
RESULTS: Sixty-four patients (42 men and 22 women; mean age, 37.5 years) with chronic fissure-in-ano were treated with 0.2 percent glyceryl trinitrate ointment. Sentinel piles were observed in 19 patients (29.7 percent). Twenty-six patients (40.6 percent) were healed initially, but 12 (46.2 percent) experienced recurrence. Mean follow-up time was 15.6 (+/-5.5) months. Twenty-nine patients (45.3 percent) had known risk factors for anal fissure, including constipation (n = 21; 32.8 percent), recent childbirth (n = 6; 9.3 percent), colonoscopy (n = 1; 1.6 percent), and anoreceptive intercourse (n = 1; 1.6 percent). Fissures were significantly less likely to heal initially (P < 0.05), more likely to recur (P < 0.05), and more likely to remain unhealed in the long term (P < 0.05) in the presence of a sentinel pile. Fissures with a history of more than six months were less likely to heal initially (P < 0.05).
CONCLUSION: The presence of a sentinel pile adversely affects the outcome of treatment of chronic anal fissures with glyceryl trinitrate ointment, and a long history of the fissure reduces the rate of initial healing. Reasons for these findings are discussed.