title: Recovery of TES-MEPs during surgical decompression of the spine: a case series of eight patients.
abstract: OBJECTIVE
  This study aimed to illustrate the recovery of transcranial electrical stimulation motor evoked potentials during surgical decompression of the spinal cord in patients with impaired motor function preoperatively. Specific attention was paid to the duration of neurologic symptoms before surgery and the postoperative clinical recovery.
  
  
  METHODS
  A case series of eight patients was selected from a cohort of 74 patients that underwent spine surgery. The selected patients initially had low or absent transcranial electrical stimulation motor evoked potentials followed by a significant increase after surgical decompression of the spinal cord.
  
  
  RESULTS
  A significant intraoperative increase in amplitude of motor evoked potentials was detected after decompression of the spinal cord or cauda equina in patients suffering from spinal canal stenosis (n = 2), extradural meningioma (n = 3), or a herniated nucleus polposus (n = 3). This was related to an enhanced neurologic outcome only if patients (n = 6) had a short onset (less than ½ year) of neurologic impairment before surgery.
  
  
  CONCLUSIONS
  In patients with a short onset of neurologic impairment because of compression of the spinal cord or caudal fibers, an intraoperative recovery of transcranial electrical stimulation motor evoked potentials can indicate an improvement of motor function postoperatively. Therefore, transcranial electrical stimulation motor evoked potentials can be considered as a useful tool to the surgeon to monitor the quality of decompression of the spinal cord.
authors.affiliation: *Department of Orthopaedics, Sint Maartenskliniek, Nijmegen, The Netherlands; and †Department of Neurosurgery, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Jetze
authors.initials: J
authors.lastname: Visser
authors.forename: Wiebe C
authors.initials: WC
authors.lastname: Verra
authors.forename: Jos M
authors.initials: JM
authors.lastname: Kuijlen
authors.forename: Philip P
authors.initials: PP
authors.lastname: Horsting
authors.forename: Henricus L
authors.initials: HL
authors.lastname: Journée
mesh_terms: D000328:Adult; D000368:Aged; D019299:Decompression, Surgical / Q000379:methods*; D004569:Electroencephalography; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D019637:Orthopedic Procedures / Q000379:methods*; D011237:Predictive Value of Tests; D011859:Radiography; D020127:Recovery of Function; D012684:Sensory Thresholds; D013117:Spinal Cord Compression / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D013131:Spine / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D065908:Transcranial Direct Current Stimulation; D016896:Treatment Outcome; D055815:Young Adult