J Korean Neurosurg Soc.  2019 Jul;62(4):367-375. 10.3340/jkns.2018.0218.

Intraoperative Neurophysiological Monitoring during Microvascular Decompression Surgery for Hemifacial Spasm

  • 1Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
  • 2Department of Neurology, Myongji Hospital, Hanyang University Medical Center, Goyang, Korea.
  • 3Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. kwanmd.park@samsung.com


Hemifacial spasm (HFS) is due to the vascular compression of the facial nerve at its root exit zone (REZ). Microvascular decompression (MVD) of the facial nerve near the REZ is an effective treatment for HFS. In MVD for HFS, intraoperative neurophysiological monitoring (INM) has two purposes. The first purpose is to prevent injury to neural structures such as the vestibulocochlear nerve and facial nerve during MVD surgery, which is possible through INM of brainstem auditory evoked potential and facial nerve electromyography (EMG). The second purpose is the unique feature of MVD for HFS, which is to assess and optimize the effectiveness of the vascular decompression. The purpose is achieved mainly through monitoring of abnormal facial nerve EMG that is called as lateral spread response (LSR) and is also partially possible through Z-L response, facial F-wave, and facial motor evoked potentials. Based on the information regarding INM mentioned above, MVD for HFS can be considered as a more safe and effective treatment.


Hemifacial spasm; Microvascular decompression surgery; Intraoperative neurophysiological monitoring

MeSH Terms

Evoked Potentials, Auditory, Brain Stem
Evoked Potentials, Motor
Facial Nerve
Hemifacial Spasm*
Intraoperative Neurophysiological Monitoring*
Microvascular Decompression Surgery*
Vestibulocochlear Nerve
Full Text Links
  • JKNS
export Copy
  • Twitter
  • Facebook
Similar articles
    DB Error: unknown error