title: Unusual causes and presentations of hemifacial spasm.
abstract: OBJECTIVE
  To evaluate unusual possible causes and clinical presentations of hemifacial spasm (HFS).
  
  
  METHODS
  The authors reviewed 1642 cases of HFS. Assessments were based on clinical features, 3-dimensional time-of-flight magnetic resonance angiography, and surgical findings. Causes other than neurovascular compression at the root exit zone of the facial nerve were investigated and unusual clinical presentations were noted.
  
  
  RESULTS
  Nine (0.5%) patients had a secondary causative structural lesion, 7 patients had a tumor, and the remaining 2 had a vascular malformation. Direct compression by dolichoectatic vertebrobasilar artery was noted in 12 (0.7%) patients. In 7 (0.4%) patients, only the distal portion of the facial nerve was compressed, and five (0.3%) had only venous compression. Bilateral HFS and tic convulsif were encountered in 7 (0.4%) and 6 (0.37%) patients, respectively. Fifty-six (3.4%) patients were younger than 30 years old at the time of microvascular decompression.
  
  
  CONCLUSIONS
  HFS can result from tumor, vascular malformation, and dolichoectatic artery. Therefore, appropriate preoperative radiological investigations are crucial to achieve a correct diagnosis. The authors emphasize that distal compression or only venous compression can be responsible for persistent or recurrent symptoms postoperatively. In cases of bilateral HFS, a definite differential diagnosis is necessary for appropriate therapy. MVD is recommended as the treatment of choice in patients younger than 30 years old or patients with painful tic convulsif.
authors: Department of Neurosurgery, Pochon CHA University College of Medicine, Sungnam, Korea.
authors: In-Bo
authors: IB
authors: Han
authors: Jong Hee
authors: JH
authors: Chang
authors: Jin Woo
authors: JW
authors: Chang
authors: Ryoong
authors: R
authors: Huh
authors: Sang Sup
authors: SS
authors: Chung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019299:Decompression, Surgical / Q000009:adverse effects / Q000379:methods; D005154:Facial Nerve; D005260:Female; D019569:Hemifacial Spasm / Q000209:etiology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000150:complications* / Q000473:pathology; D019635:Neurosurgical Procedures / Q000009:adverse effects / Q000379:methods; D012189:Retrospective Studies; D014652:Vascular Diseases / Q000150:complications* / Q000601:surgery; D055815:Young Adult