Botulinum Toxin Injection Plus Topical Diltiazem for Chronic Anal Fissure: A Randomized Double-Blind Clinical Trial and Long-term Outcome.

Background: Chemical sphincterotomy avoids the risk of permanent incontinence in the treatment of chronic anal fissure, but it does not reach the efficacy of surgery and recurrence is high. Drug combination has been proposed to overcome these drawbacks.

Objective: This study aimed to compare the clinical, morphological, and functional effects of combined therapy with botulinum toxin injection and topical diltiazem in chronic anal fissure and to assess the long-term outcome after healing.