title: The incidence of unacceptable movement with motor evoked potentials during craniotomy for aneurysm clipping.
abstract: OBJECTIVE
  To review the experience at a single institution with motor evoked potential (MEP) monitoring during intracranial aneurysm surgery to determine the incidence of unacceptable movement.
  
  
  METHODS
  Neurophysiology event logs and anesthetic records from 220 craniotomies for aneurysm clipping were reviewed for unacceptable patient movement or reason for cessation of MEPs. Muscle relaxants were not given after intubation. Transcranial MEPs were recorded from bilateral abductor hallucis and abductor pollicis muscles. MEP stimulus intensity was increased up to 500 V until evoked potential responses were detectable.
  
  
  RESULTS
  Out of 220 patients, 7 (3.2%) exhibited unacceptable movement with MEP stimulation-2 had nociception-induced movement and 5 had excessive field movement. In all but one case, MEP monitoring could be resumed, yielding a 99.5% monitoring rate.
  
  
  CONCLUSIONS
  With the anesthetic and monitoring regimen, the authors were able to record MEPs of the upper and lower extremities in all patients and found only 3.2% demonstrated unacceptable movement. With a suitable anesthetic technique, MEP monitoring in the upper and lower extremities appears to be feasible in most patients and should not be withheld because of concern for movement during neurovascular surgery.
authors.affiliation: Department of Anesthesiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA; Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA.
authors.forename: Laura B
authors.initials: LB
authors.lastname: Hemmer
authors.affiliation: Department of Anesthesiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA; American University of Beirut, Riad El Solh, Beirut, Lebanon.
authors.forename: Carine
authors.initials: C
authors.lastname: Zeeni
authors.affiliation: Department of Anesthesiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA; Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA.
authors.forename: John F
authors.initials: JF
authors.lastname: Bebawy
authors.affiliation: Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA; Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA.
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Bendok
authors.affiliation: Neurological Testing Center, Northwestern Memorial Hospital, Chicago, Illinois, USA.
authors.forename: Mathew A
authors.initials: MA
authors.lastname: Cotton
authors.affiliation: Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, Illinois, USA.
authors.forename: Neil B
authors.initials: NB
authors.lastname: Shah
authors.affiliation: Department of Anesthesiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA; Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA. Electronic address: dhanesh-gupta@northwestern.edu.
authors.forename: Dhanesh K
authors.initials: DK
authors.lastname: Gupta
authors.affiliation: Department of Anesthesiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA; Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA; Department of Neurology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA.
authors.forename: Antoun
authors.initials: A
authors.lastname: Koht
mesh_terms: D000758:Anesthesia; D002548:Cerebral Revascularization / Q000379:methods*; D003399:Craniotomy / Q000379:methods*; D004558:Electric Stimulation; D004569:Electroencephalography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D006801:Humans; D007036:Hypothermia, Induced; D002532:Intracranial Aneurysm / Q000601:surgery*; D007432:Intraoperative Period; D016343:Monitoring, Intraoperative / Q000379:methods*; D009068:Movement; D009125:Muscle Relaxants, Central / Q000627:therapeutic use; D018482:Muscle, Skeletal / Q000502:physiology; D019635:Neurosurgical Procedures / Q000379:methods*; D012189:Retrospective Studies
chemical_list: D009125:Muscle Relaxants, Central