Botulinum toxin injection versus lateral internal sphincterotomy in the treatment of chronic anal fissure: a randomized controlled trial

Abstract

Background: Although lateral internal sphincterotomy has been the gold standard of treatment for chronic anal fissure, the main concern remains its effects on anal continence. Intrasphincteric injection of botulinum toxin seems to be a reliable option providing temporary alleviation of sphincter spasm and allowing the fissure to heal. The aim of the present prospective controlled randomized study was to compare the outcome of lateral internal sphincterotomy and botulinum toxin injection treatments in patients with uncomplicated chronic anal fissure.

Methods: Eighty consecutive patients with uncomplicated chronic anal fissure who had failed conservative treatment were randomized to receive either intrasphincteric injection of botulinum toxin (BT) or lateral internal sphincterotomy (LIS). Postoperative pain relief, healing of fissure, continence scores, and fissure relapse during 18 weeks of follow-up were the outcomes assessed.

Results: There was a statistically significantly higher healing in the LIS group than the BT group (p = 0.0086 and 95% CI = 7.38-45.69%). In addition, LIS was associated with a high rate of anal incontinence as compared to BT (p = 0.0338 and 95% CI = -1.64-27.53%). The recurrence rate in the BT group was significantly higher statistically than that in the LIS group (p = 0.0111 and 95% CI = 6.68-46.13%).

Conclusions: Surgical internal sphincterotomy has a higher healing rate and a lower recurrence rate than intrasphincteric injection of botulinum toxin in the treatment of uncomplicated chronic anal fissure. Injection of botulinum toxin, however, is a simple noninvasive technique that avoids the greater risk of incontinence. It could be used as the first therapeutic approach in patients without clinical risk factors of recurrence.