Botulinum toxin injection into the internal anal sphincter (IAS) is a second line therapy for anal fissures.
High-dose circumferential chemodenervation (HDCC) of 100 IU is proposed.
Of the 62 patients, the overall success rate was greater than 70% at 3 months follow-up.
Combination therapy involving HDCC-IAS is a safe and effective method.