Low Versus High Dose OnabotulinumtoxinA for Chronic Anal Fissure

Background: Severe anal pain and a lower quality of life are two consequences of chronic anal fissure (CAF). The ideal dosage for botulinum toxin type A (BoNT-A), a sphincter-preserving substitute for lateral internal sphincterotomy, is still unknown. In this study, fixed-site 20 U and 50 U onabotulinumtoxinA regimens were compared using a structured 1-year follow-up and a standard injection technique at 3 and 9 o'clock. Aim of the study:The aim of the work is to evaluate the efficacy of botulinum toxin injection in treatment of patients with chronic anal fissures comparing between two doses of botulinum toxin injection focusing on healing rate, fissure pain, incontinence and return to daily activity Methods: OnabotulinumtoxinA 20 U (10 U per site) or 50 U (25 U per site) were randomly assigned to 70 adults with CAF who were refractory to at least 8 weeks of medical therapy in this prospective, randomized, double-blind, parallel-group trial. At eight weeks, complete clinical fissure healing was the main result. Pain and bleeding response, healing time, recurrence following initial healing, temporary flatus incontinence, and the need for surgery during a one-year follow-up were secondary outcomes. Recurrent and persistent non-healing cases went straight to surgery instead of another injection.