title: Discrepancy between voluntary movement and motor-evoked potentials in evaluation of motor function during clipping of anterior circulation aneurysms.
abstract: BACKGROUND
  Various modalities have been used to confirm the blood flow through parent arteries or surrounding perforating arteries during surgical aneurysm clipping, including motor-evoked potentials (MEPs), Doppler ultrasound, and indocyanine green videoangiography. Nonetheless, contralateral hemiparesis due to arterial blood flow insufficiency may arise because of false-positive or false-negative errors. By performing controlled intraoperative awakening during aneurysm clipping, we compared patients' voluntary movements with simultaneous MEP.
  
  
  METHODS
  Four patients with anterior choroidal artery aneurysms and one patient with a dorsal internal carotid artery aneurysm were included in this study. MEP and intraoperative voluntary movements under awake craniotomy were assessed simultaneously during and after the clipping procedure.
  
  
  RESULTS
  Aneurysms were safely and successfully clipped in all patients, with no evidence of postoperative neurological deficits. Voluntary movements and MEP findings did not differ from the control state in three patients. In the other two patients, we observed a discrepancy between MEP amplitudes and voluntary movements. In one patient, deterioration and subsequent improvement in voluntary movements were preceded by MEP amplitude reduction during clipping. In the other patient, MEP amplitude did not change although voluntary movement deteriorated during temporary occlusion of the internal carotid artery.
  
  
  CONCLUSIONS
  Intraoperative neurological assessment during aneurysmal clipping under awake craniotomy is feasible and safe, and should be valuable for the assessment of ischemia, especially in the anterior choroidal artery. From a neurophysiologic viewpoint, MEP may be insufficiently sensitive for evaluating voluntary movement under ischemia.
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mikami
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Sugino
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Wanibuchi
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Miyamoto
authors.affiliation: National Cerebral and Cardiovascular Center, Osaka, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Hashimoto
authors.affiliation: Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan. Electronic address: mikunin@sapmed.ac.jp.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mikuni
mesh_terms: D000328:Adult; D000368:Aged; D000758:Anesthesia; D001932:Brain Neoplasms / Q000601:surgery; D056805:Consciousness Monitors; D003399:Craniotomy; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009068:Movement / Q000502:physiology*; D019635:Neurosurgical Procedures / Q000379:methods*
keywords: Anterior choroidal artery aneurysm; Awake craniotomy; Indocyanine green videoangiography; Motor-evoked potentials