title: Long-term outcome of the use of botulinum toxin injection for functional anal pain.
abstract: OBJECTIVE
  Anal pain may occur in the absence of demonstrable anal pathology. Spasm of the sphincter muscles has been suggested as a cause in some patients. We aimed to assess the effectiveness of injection of botulinum toxin in treating this condition.
  
  
  METHODS
  Patients who had injection of botulinum toxin over a 3-year period were identified retrospectively. Patients were excluded if anal fissure or other organic pathology was found to account for their symptoms on examination under anaesthetic. Long-term outcome was assessed at a minimum 3-year post-procedure telephone follow up.
  
  
  RESULTS
  Fourteen (eight male) patients were identified, of median age 50 years. Botulinum toxin (20-200 u) was injected into the internal sphincter. Seven of the 14 patients reported significant improvement in symptoms at 3 months. Seven were available for a structured telephone review at a median of 59 (42-68) months. The four patients who had benefited from the injection had remained asymptomatic.
  
  
  CONCLUSIONS
  Injection of botulinum toxin into the internal anal sphincter has a role in alleviating symptoms in a small proportion of patients with functional anal pain.
authors.affiliation: St Mark's Hospital, Harrow, Middlesex, UK.
authors.forename: J R F
authors.initials: JR
authors.lastname: Hollingshead
authors.forename: Y
authors.initials: Y
authors.lastname: Maeda
authors.forename: T J
authors.initials: TJ
authors.lastname: Brown
authors.forename: J
authors.initials: J
authors.lastname: Warusavitarne
authors.forename: C J
authors.initials: CJ
authors.lastname: Vaizey
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000187:drug effects* / Q000503:physiopathology; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage / Q000627:therapeutic use*; D059350:Chronic Pain / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A