title: Intra-operative monitoring of lower extremity motor-evoked potentials by direct cortical stimulation.
abstract: OBJECTIVE
  Motor-evoked potentials (MEPs) are commonly recorded from upper-extremity muscles, whereas lower-extremity MEP (LE-MEP) monitoring has not been adequately established. The goal of the study was to develop a MEP monitoring method using direct cortical stimulation (DCS) for predicting motor deficits of lower extremities.
  
  
  METHODS
  Intra-operative LE-MEP monitoring was performed in 22 patients. After craniotomy, a subdural electrode was placed on the cortex so that the optimal contact was positioned 2 cm lateral from the midline on the motor cortex. The electrodes for stimulation consisted of a cathode at Fpz and an anode at the optimal contact site on the motor cortex. After stimulation was performed with short trains of five stimuli, LE-MEPs were recorded from the lower-limb muscles.
  
  
  RESULTS
  LE-MEPs were consistently recorded in all patients. Disappearance or amplitude reduction of MEP waveforms was observed in five patients, but the MEP waveforms had recovered and remained at the control level by dural closure, and no permanent motor deficit was observed in any patient.
  
  
  CONCLUSIONS
  We accomplished LE-MEP recording during supratentorial surgery using monopolar DCS with a subdural electrode placed on the convex side of the motor cortex.
  
  
  CONCLUSIONS
  A useful method of intra-operative LE-MEP recording was described.
authors: Department of Neurosurgery, Yamaguchi University School of Medicine, Ube, Japan.
authors: Yuichi
authors: Y
authors: Maruta
authors: Masami
authors: M
authors: Fujii
authors: Hirochika
authors: H
authors: Imoto
authors: Sadahiro
authors: S
authors: Nomura
authors: Fumiaki
authors: F
authors: Oka
authors: Hisaharu
authors: H
authors: Goto
authors: Satoshi
authors: S
authors: Shirao
authors: Kouichi
authors: K
authors: Yoshikawa
authors: Hiroshi
authors: H
authors: Yoneda
authors: Makoto
authors: M
authors: Ideguchi
authors: Eiichi
authors: E
authors: Suehiro
authors: Hiroyasu
authors: H
authors: Koizumi
authors: Hideyuki
authors: H
authors: Ishihara
authors: Shoichi
authors: S
authors: Kato
authors: Koji
authors: K
authors: Kajiwara
authors: Michiyasu
authors: M
authors: Suzuki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000503:physiopathology / Q000601:surgery; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*