title: Hemifacial spasm: results of treatment with low dose botulinum toxin injection.
abstract: BACKGROUND
  Hemifacial Sapsm (HFS) is a common movement disorder in Thailand. Botulinum toxin type A (BTA) is an effective and safe treatment for this condition. The success of BTA treatment depends on the experience of the clinician.
  
  
  OBJECTIVE
  To study the demographic data, efficacy and safety of low dose BTA injection in HFS patients.
  
  
  METHODS
  The Spastic and Dystonia Clinic, Department of Rehabilitation Medicine, King Chulalongkorn Memorial Hospital.
  
  
  METHODS
  Open-label, prospective case-series study.
  
  
  METHODS
  All patients with HFS referred for BTA injection from December 1st, 1995 to November 30th, 2003.
  
  
  METHODS
  Sex, age, side of spasm, onset of symptoms before BTA injection, underlying diseases, sites of BTA injection, dose of each BTA treatment, duration of response, efficacy, and side-effects were analyzed. 3-5 units of BOTOX were intramuscularly injected per site to all muscles that had spasm. After injection, a 20-minute cold compression on the first day was followed by 20-minute warm compression with massage at each injection site per day for 14 days.
  
  
  RESULTS
  A total of 112 patients with HFS were treated with 874 BTA treatments. There were 71 females (63.4%) and 41 males (36.6%). The mean age was 45 years. 75 patients (67%) were affected on the left side. Mean duration of symptoms was 3.4 years. The sites of injection were orbicularis occuli and orbicularis oris muscles in all 874 treatments (100%). The mean dose of all treatments was 25 units. The mean initial dose was 30.5 units. The mean dose for subsequent injection was 23 units. The mean duration between treatments was 4.7 months. The mean initial duration was 3.5 months. The mean duration for subsequent injection was 4.8 months. The outcomes of treatment assessed at 4 weeks after injection classified as excellent (>80% improvement) were found in 845 treatments (96.7%). Most treatments had no complication (91.9%). Ptosis, facial paresis and double vision were mild and transient, lasting 1-4 weeks. There were no long-term complications of BTA treatment in the present series.
  
  
  CONCLUSIONS
  Low dose BTA injection is an effective treatment for hemifacial spasm patients. There was a longer duration of response in subsequent injections and a lower complication rate in the present study when compared to others.
authors.affiliation: Department of Rehabilitation Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Areerat
authors.initials: A
authors.lastname: Suputtitada
authors.forename: Kammant
authors.initials: K
authors.lastname: Phanthumchinda
authors.forename: Chaichon
authors.initials: C
authors.lastname: Locharernkul
authors.forename: Nijasri C
authors.initials: NC
authors.lastname: Suwanwela
mesh_terms: D000328:Adult; D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D019569:Hemifacial Spasm / Q000188:drug therapy*; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A