Therapeutic properties of botulinum toxin on chronic anal fissure treatment and the patient factors role

BACKGROUND: One of the most frequent distressing diseases which causes anal pain and bleeding after defecation is anal fissure. Despite a poorly understood pathogenesis, the internal anal sphincter spasm has been identified to play a central role in pathogenesis. Recently, botulinum toxin is being used increasingly for the treatment of chronic anal fissure to achieve chemical sphincterotomy and reduce internal sphincter tonicity. Based on the heterogeneity among the published studies, we aimed this study to evaluate its healing rate and for recognizing the factors of patients which may affect the outcome. SUBJECTS AND METHODS: In a prospective case series medical research, 106 patients who suffer from chronic anal fissure were treated by botulinum toxin injections. All patients received 30 units of botulinum toxin and were physically examined every week for 2 months. They were evaluated for bleeding, pain, hematoma, thrombosis, infection, incontinence, and healing of the fissure. At the end of the follow-up period, the fissure healing rate and its relation to age, gender, prior topical therapy, duration of symptoms, and the position of the fissure were assessed. RESULTS: At the end of the study (8 weeks), the healing rate was 84.9% (90 patients responded to injections). Healing rate was higher in females and in patients who experienced a shorter duration of symptoms before injection. The mean healing time was 4.68 weeks. In addition, patients with one fissure (anterior or posterior) demonstrated higher healing rate and shorter healing time compared to patients with two fissures (anterior and posterior). CONCLUSION: This study demonstrated that botulinum toxin injection is safe and effective for the treatment of chronic anal fissures, with a low complication rate. In addition, the healing rate was higher in females, patients with shorter duration of symptoms, and those with one fissure.