title: High-dose circumferential chemodenervation of the internal anal sphincter: A new treatment modality for uncomplicated chronic anal fissure: A retrospective cohort study (with video).
abstract: BACKGROUND
  Botulinum toxin injection into the internal anal sphincter is gaining popularity as a second line therapy for chronic anal fissures if medical therapy fails. The dosage of botulinum toxin reported ranged from 20 to 50 IU with no more than 3 injection sites and results in a healing rate of 41%-88% at 3 months. We propose a new injection method of high-dose circumferential chemodenervation of 100 IU in treating chronic anal fissure.
  
  
  METHODS
  This was a retrospective review at a single academic center. 75 patients (50 women and 25 men) with uncomplicated chronic anal fissures underwent high-dose circumferential chemodenervation-internal anal sphincter (100 IU). We measured fissure healing, complication, and recurrence rates at 3 and 6 months post injection.
  
  
  RESULTS
  Of the 75 patients, healing rate was 90.7% at 3 months follow up with the first injection and 81.3% with the second injection. The recurrence rates were 20.6% and 12.5% at 6 months after the 1st and 2nd injections respectively. Excluding 5 patients who lost follow up, the total healing rate of the study cohort was 100%. At 2 weeks and 3 months, there were no major complications including hematoma, infection, flatus, fecal, and urinary incontinence.
  
  
  CONCLUSIONS
  High-dose circumferential chemodenervation-internal anal sphincter (100 IU) is a safe and effective method for uncomplicated chronic anal fissure.
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
authors.forename: Porter H
authors.initials: PH
authors.lastname: Glover
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA. Electronic address: stang@umc.edu.
authors.forename: Shou-jiang
authors.initials: SJ
authors.lastname: Tang
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
authors.forename: James Z
authors.initials: JZ
authors.lastname: Whatley
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Davis
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
authors.forename: Kellen T
authors.initials: KT
authors.lastname: Jex
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
authors.forename: Ruonan
authors.initials: R
authors.lastname: Wu
authors.affiliation: Department of Surgery, University of Mississippi Medical Center, 2500 North State Street Jackson, MS 39216, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lahr
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000294:innervation*; D001905:Botulinum Toxins / Q000008:administration & dosage*; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D005401:Fissure in Ano / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D009498:Neurotoxins / Q000008:administration & dosage*; D012008:Recurrence; D012189:Retrospective Studies; D016896:Treatment Outcome; D014549:Urinary Incontinence; D014945:Wound Healing
chemical_list: D009498:Neurotoxins; D001905:Botulinum Toxins
keywords: Botulinum toxin; Chronic anal fissure; Healing rate; High-dose circumferential chemodenervation; Injection; Lateral internal sphincterotomy