title: The effect of microvascular decompression for hemifacial spasm caused by vertebrobasilar dolichoectasia.
abstract: OBJECTIVE
  Hemifacial spasm (HFS) caused by vertebrobasilar dolichoectasia (VBD) is very rare, and in theses cases, it is difficult to decompress the nerve from its vascular compression. The objective of this study was to investigate the outcome of microvascular decompression (MVD) for HFS caused by VBD.
  
  
  METHODS
  There were 10 patients of HFS caused by VBD at our hospital between September 1978 and September 2008. We evaluated magnetic resonance angiography (MRA) and time of flight magnetic resonance imaginge (TOF MRI) findings using the criteria for VBD. We compared the clinical outcomes of MVD for the 10 patients with VBD with the overall outcomes of the total 2058 MVDs performed for HFS.
  
  
  RESULTS
  The results of MVD for HFS caused by VBD were successful in 90.9% of cases. The postoperative complication rate in VBD was 45.5%. Offending vessels in patients with VBD were identified visually during surgery. Adverse effects after MVD were found in 4 patients. We found that the diameter of VBD was significantly greater in patients with complications than in those with no complications (p=0.028).
  
  
  CONCLUSIONS
  Our data shows that MVD may be a good treatment modality for HFS caused by VBD but care must be taken to avoid adverse effects from the procedure. It is important to detach the dolichoectatic artery from its surrounding structures sufficiently to allow it to be easily movable. In addition, attempts should be made to lessen the retraction of the cerebellum during release of the dolichoectatic artery.
authors.affiliation: Department of Neurosurgery, Severance Hospital, Brain Korea 21 Project for Medical Science, Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea. ; Department of Neurosurgery, Gandong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
authors.forename: Jeong-Han
authors.initials: JH
authors.lastname: Kang
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Kang
authors.forename: Sang Sup
authors.initials: SS
authors.lastname: Chung
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Chang
keywords: Hemifacial spasm; Microvascular decompression; Vertebrobasilar dolichoectasia