title: Is hemifacial spasm a phenomenon of the central nervous system? --The role of desflurane on the lateral spread response.
abstract: OBJECTIVE
  A signature EMG feature of hemifacial spasm (HFS) is the lateral spread response (LSR). Desflurane is a common anesthetic with potent effects on synaptic transmission. We tested the hypothesis that the LSR is mediated by corticobulbar components by comparing the LSR during total intravenous anesthesia (TIVA) or TIVA plus desflurane during microvascular decompression (MVD) surgery.
  
  
  METHODS
  22 HFS patients undergoing MVD surgery participated in this prospective study. The LSR data was recorded from the o. oculi, o. oris and mentalis muscles prior to opening dura. LSR onset latencies and amplitudes were determined under TIVA and TIVA/desflurane (0.5 and 1MAC). Facial muscle LSRs and EEG were analyzed.
  
  
  RESULTS
  Desflurane (1MAC) significantly decreased the LSR amplitude in all 3 facial muscles (p<0.01). Pooled LSR data from all facial muscles showed desflurane inhibited the LSR amplitude by 43% compared to TIVA (p<0.001). No effects on the latency of the LSR or on EEG state were observed.
  
  
  CONCLUSIONS
  LSR inhibition by desflurane suggests a central mechanism involvement in the genesis of this signature HFS response.
  
  
  CONCLUSIONS
  This study demonstrates that facial nerve vascular compression and plastic changes within the CNS are part of the pathophysiology of HFS.
authors.affiliation: Section of Neurosurgery, Faculty of Medicine, University of Manitoba and Health Sciences Centre, Winnipeg, MB, Canada.
authors.forename: Marshall F
authors.initials: MF
authors.lastname: Wilkinson
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, Faculty of Medicine, University of Manitoba and Health Sciences Centre, Winnipeg, MB, Canada.
authors.forename: Tumul
authors.initials: T
authors.lastname: Chowdhury
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, Faculty of Medicine, University of Manitoba and Health Sciences Centre, Winnipeg, MB, Canada.
authors.forename: W Alan C
authors.initials: WA
authors.lastname: Mutch
authors.affiliation: Section of Neurosurgery, Faculty of Medicine, University of Manitoba and Health Sciences Centre, Winnipeg, MB, Canada. Electronic address: akaufmann@hsc.mb.ca.
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Kaufmann
mesh_terms: D061605:Administration, Intravenous; D000293:Adolescent; D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000494:pharmacology; D002490:Central Nervous System / Q000187:drug effects / Q000503:physiopathology*; D000077335:Desflurane; D004569:Electroencephalography; D004576:Electromyography; D005152:Facial Muscles / Q000294:innervation*; D005154:Facial Nerve / Q000187:drug effects* / Q000503:physiopathology; D005260:Female; D019569:Hemifacial Spasm / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007530:Isoflurane / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D061145:Microvascular Decompression Surgery; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D011446:Prospective Studies; D011930:Reaction Time / Q000187:drug effects* / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D018685:Anesthetics, Inhalation; D000077335:Desflurane; D007530:Isoflurane
keywords: Desflurane; Facial nerve; Hemifacial spasm; Lateral spread response; Microvascular decompression; Total intravenous anesthesia (TIVA)