title: Prospective study of microvascular decompression in hemifacial spasm.
abstract: OBJECTIVE
  Although, in most cases, the symptoms of hemifacial spasm (HFS) disappear immediately after microvascular decompression (MVD), in some cases, they disappear more gradually. The objectives of this study were to observe the time course and the rate of the delayed resolution and to attempt to explain the phenomenon through long-term follow-up of HFS after MVD.
  
  
  METHODS
  Two hundred and sixty-one patients with HFS who underwent MVD were followed up to observe clinical changes. Two hundred and twenty-six of the 261 patients were followed up for a duration of 6 months to 2 years, from 1985 to 1995.
  
  
  RESULTS
  After the 1st week of the surgery, 61.1% of the patients were rated as having achieved excellent results. When the patients were followed up for more than 6 months, however, the rate improved to 82.7%. The clinical results of HFS after MVD improved significantly with time (P < 0.05). Delayed resolution of HFS was observed in 37.4% of the patients who experienced complete resolution; it was the most important factor for clinical improvement during the follow-up period. Abnormal muscle response immediately after MVD in the operating room was also positively correlated with resolution during the follow-up period (correlation coefficient = 0.3099, P < 0.05).
  
  
  CONCLUSIONS
  In conclusion, the clinical picture of HFS after MVD improves with time, and abnormal muscle response can be used as a prognostic indicator for the resolution of HFS during the follow-up period.
authors.affiliation: Department of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: J C
authors.initials: JC
authors.lastname: Shin
authors.forename: U H
authors.initials: UH
authors.lastname: Chung
authors.forename: Y C
authors.initials: YC
authors.lastname: Kim
authors.forename: C I
authors.initials: CI
authors.lastname: Park
mesh_terms: D000328:Adult; D002536:Cerebral Arteries / Q000601:surgery*; D005152:Facial Muscles / Q000294:innervation / Q000503:physiopathology; D005154:Facial Nerve / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology; D011446:Prospective Studies; D013035:Spasm / Q000209:etiology / Q000601:surgery*; D016896:Treatment Outcome; D014711:Vertebral Artery / Q000601:surgery