title: Lack of effficacy of botulinum toxin in chronic anal fissure.
abstract: OBJECTIVE
  Hypertonicity of internal anal sphincter plays a major role in the persistence of chronic anal fissure. Botulinum toxin could induce internal anal sphincter relaxation without the adverse effects of surgery (long-term faecal incontinence) or topical nitrates (anal burning, headaches, hypotension).
  
  
  METHODS
  We conducted a placebo-controlled, randomised, double-blind study to assess the efficacy of a single injection of botulinum toxin in the internal anal sphincter of patients with chronic anal fissure in six ambulatory care clinics. Eligibility criteria included a mean value of post-defecation anal pain >or= 30 mm on a 100 mm visual analogue scale over the week preceding inclusion. Main endpoint was the proportion of patients with symptomatic improvement during the fourth week after inclusion (post-defecation anal pain below 10 mm).
  
  
  RESULTS
  Forty-four patients (22 in each group) were included. At inclusion, there was no significant difference between groups on age, sex ratio, pain duration, post-defecation anal pain, analgesic consumption and stool frequency. Ten (45%) and 11 (50%) patients reported symptomatic improvement on the main endpoint (P=0.76) in placebo and botulinum toxin groups, respectively. Ten patients (five in each group) had healed fissure at week 4 and ten patients (five in each group) required surgical treatment between weeks 4 and 12. Similarly, there was no significant difference between groups on other variables between weeks 4 and 12.
  
  
  CONCLUSIONS
  The efficacy of a single injection of botulinum toxin in the internal anal sphincter does not differ from that of a placebo in patients with chronic anal fissure.
authors.affiliation: Service des Maladies de l'Appareil Digestif, Hôpital de Pontchaillou, Rennes, France. laurent.siproudhis@chu-rennes.fr
authors.forename: L
authors.initials: L
authors.lastname: Siproudhis
authors.forename: V
authors.initials: V
authors.lastname: Sébille
authors.forename: F
authors.initials: F
authors.lastname: Pigot
authors.forename: P
authors.initials: P
authors.lastname: Hémery
authors.forename: F
authors.initials: F
authors.lastname: Juguet
authors.forename: E
authors.initials: E
authors.lastname: Bellissant
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001905:Botulinum Toxins / Q000008:administration & dosage*; D002908:Chronic Disease; D004311:Double-Blind Method; D005260:Female; D005401:Fissure in Ano / Q000188:drug therapy*; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged
chemical_list: D001905:Botulinum Toxins