title: [Intraoperative monitoring of motor evoked potentials during glioma removal].
abstract: OBJECTIVE
  To determine whether motor evoked potentials(MEPs)provide reliable monitoring of the motor system during resection of gliomas in or adjacent to the motor cortex or pyramidal tract.
  
  
  METHODS
  MEP recording was performed during 64 operations in 55 patients harboring gliomas. Intraoperative MEP findings were classified into 3 groups:Group A was defined as having no significant MEP changes, Group B as having reversible MEP changes(?50% amplitude decrease or loss), and Group C as having irreversible changes. Postoperative motor function was evaluated according to the presence/absence of deterioration immediately after surgery and 1 month later, as compared to preoperative motor status
  
  
  RESULTS
  Immediately after surgery, 13 of 39(33%)patients in Group A, 6 of 17(35%)in Group B, and 7 of 8(88%)in Group C experienced deterioration of motor function. One month after surgery, 4 of 39(10%)patients in Group A, 3 of 17(18%)in Group B, and 4 of 8(50%)showed deterioration of motor function. Both immediately(χ2=8.3, p<0.05)and 1 month(χ2=6.9, p<0.05)after surgery, MEP alterations correlated significantly with postoperative deterioration of motor function. Despite MEPs being stable throughout surgery(Group A), there were some patients with deterioration of motor function initially appearing to represent false negative monitoring. However, these deteriorations were confirmed to have been caused by secondary hemorrhage, venous return dysfunction, postoperative convulsion, or resection of the supplementary motor area.
  
  
  CONCLUSIONS
  MEP monitoring provides reliable information on the motor system during glioma surgery. Although false negative MEP results may exist in some patients, most data were not influenced by intraoperative manipulation but rather were attributable to secondary postoperative events.
authors: Department of Neurosurgery, University of Niigata, Japan.
authors: Masafumi
authors: M
authors: Fukuda
authors: Makoto
authors: M
authors: Oishi
authors: Tetsuro
authors: T
authors: Takao
authors: Tetsuya
authors: T
authors: Hiraishi
authors: Tsutomu
authors: T
authors: Kobayashi
authors: Hiroshi
authors: H
authors: Aoki
authors: Ryosuke
authors: R
authors: Ogura
authors: Akihiko
authors: A
authors: Saito
authors: Yukihiko
authors: Y
authors: Fujii
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000601:surgery*; D002648:Child; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005910:Glioma / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D011712:Pyramidal Tracts / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult