Glyceryl trinitrate vs. lateral sphincterotomy for chronic anal fissure: prospective, randomized trial

Glyceryl trinitrate has been shown to be an effective treatment for chronic anal fissure. It decreases anal tone and ultimately heals anal fissures. The aim of this trial was to compare glyceryl trinitrate with lateral sphincterotomy (current standard treatment) as definitive management for chronic anal fissure.

All patients with symptoms of chronic anal fissure were randomly assigned to one of two treatment arms. The glyceryl trinitrate group applied 0.2 percent paste to the perianal area three times a day for eight weeks. Patients in the lateral sphincterotomy group underwent surgery on the next available operating list. Patients were reviewed at two weekly intervals until the fissure healed.

Sixty-five patients were enrolled in the trial, with 31 in the lateral sphincterotomy group and 34 in the glyceryl trinitrate group. Five patients were excluded after randomization. Twenty of 33 (60.6 percent) glyceryl trinitrate patients had healed fissures in eight weeks compared with 26 of 27 (97 percent) in the sphincterotomy group (P = 0.001). Twelve patients in the glyceryl trinitrate group had little improvement in their symptoms and underwent lateral sphincterotomy. Poor tolerance and poor compliance with treatment were important factors in patients whose fissures did not heal with glyceryl trinitrate. Fissures healed significantly faster after sphincterotomy compared with glyceryl trinitrate treatment (P = 0.0001). Nine of the 20 patients whose fissures healed with glyceryl trinitrate paste subsequently had a recurrence of their fissures. There were no long-term complications from lateral sphincterotomy.

Glyceryl trinitrate paste heals the majority of chronic anal fissures. However, a significant minority have little improvement or develop side effects and require conventional surgical treatment. Poor compliance with prescribed treatment often contributes to nonhealing. In addition, some fissures which initially heal with glyceryl trinitrate paste recur and require further treatment. Glyceryl trinitrate treatment is labor intensive for patients and physicians and has not been shown to be superior to lateral sphincterotomy.