Preoperative Three-Dimensional Diagnosis of Neurovascular Relationships at the Root Exit Zones During Microvascular Decompression for Hemifacial Spasm

World Neurosurg. 2016 Aug:92:171-178. doi: 10.1016/j.wneu.2016.05.005. Epub 2016 May 10.

Abstract

Objective: Hemifacial spasm occurs when a blood vessel compresses against an area near the root exit zone of the facial nerve. Developments in diagnostic neuroimaging have allowed three-dimensional (3D) observation of artery and nerve locations, an effective aid for treatment selection. However, an accurate interpretation of the 3D data remains challenging because imaging representations of complex small vessels are drowned out by noise. We used a noise elimination method to analyze artery and nerve locations and to determine their 3D relationship.

Methods: Fifteen patients treated for hemifacial spasm were included. Images fused from 3 modalities of magnetic resonance imaging, 3D computed tomography, and angiography were used as source images. Using the images, models of the nerve and candidate vessels were created and shown in 3D to observe how the arteries were compressing the nerve and to identify the portions of the offending vessels that were closest to the nerve. These preoperative results were then compared with operative field observations during surgery. 3D models of the unaffected side were created and evaluated as controls.

Results: We confirmed that these models were accurate reconstructions of the source images as the tubular nerve and artery cross-sections showed good alignment onto magnetic resonance imaging axial slice images. The preoperative diagnoses of the compression sites and offending arteries all matched intraoperative findings.

Conclusions: An accurate identification of the offending arteries and compression sites was possible, and this method is anticipated to offer effective means of preoperative simulation.

Keywords: Hemifacial spasm; Microvascular decompression; Three-dimensional surgical simulation.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Facial Nerve / diagnostic imaging
  • Facial Nerve / surgery
  • Female
  • Hemifacial Spasm / diagnostic imaging*
  • Hemifacial Spasm / surgery*
  • Humans
  • Imaging, Three-Dimensional* / methods
  • Magnetic Resonance Angiography
  • Magnetic Resonance Imaging
  • Male
  • Microvascular Decompression Surgery / methods*
  • Middle Aged
  • Nerve Compression Syndromes / etiology
  • Preoperative Care*
  • Treatment Outcome