Perianal topical nitroglycerin has been widely used as a means for avoiding surgery in patients with anal fissure. However, nitroglycerin has not been universally accepted for this application because of inconsistency of efficacy and side effects. Recent studies (Dis Colon Rectum. 2007 Apr;50(4):509-16) have demonstrated that nitroglycerin ointment products compounded by pharmacies did not meet the USP specifications for potency and/or content uniformity when filling a prescription for 0.3 percent nitroglycerin ointment. These results raise significant issues as to whether the patient is put at undue risk relative to the relief of their anal fissure pain. In addition, one study (Dis Colon Rectum. 2006 Jun;49(6):865-8) has demonstrated that intra-anal dosing of topical nitroglycerin produces a significantly greater reduction in sphincteric pressure and lower incidence of headaches than with perianal administration of the same dose of ointment.

Topical glyceryl trinitrate 0.4% ointment has been developed and tested in clinical trials and is effective in healing chronic anal fissures. It assures exactly dose and concentration of nitroglycerin.

Hypothesis: The endoanal application of exactly dose and concentration of nitroglycerin must reduced headache and the final recurrence.

The purpose of this study is:

1. Principal end-point: to compare perianal vs endoanal application of Rectogesic and evaluate the different morbidity of the two presentation

inclusion criteria: chronic anal fissure. Outcome measures: recurrence and headache.

Inclusion Criteria:

• Before a definitive definition of chronic anal fissure and ensuring inclusion in the study, all patients diagnosed as having chronic anal fissure based on their medical history and physical exploration were treated for a minimum of six weeks with conservative medical treatment (high residue diet, analgesics, and warm sitz baths). Chronic anal fissure was defined by the presence of a fibrous induration or exposed internal sphincter fibres.

Exclusion Criteria:

• Associated anal pathologies (incontinence, stenosis, abscess, fistula and haemorrhoids)
• Patients with associated conditions (inflammatory bowel disease, acquired immunodeficiency syndrome, tuberculosis, sexually transmitted disease and immunosuppression)
• Cardiopathy
• Headache and pregnancy.