Utility and the limit of motor evoked potential monitoring for preventing complications in surgery for cerebral arteriovenous malformation.
OBJECTIVE
To evaluate the usefulness of motor evoked potential (MEP) monitoring and mapping in arteriovenous malformation surgery.


METHODS
Intraoperative MEP monitoring was performed in 21 patients whose AVMs were located near the motor area or fed by arteries related to the corticospinal tract to detect blood flow insufficiency and/or direct injury to the corticospinal tract and/or to map the motor area.


RESULTS
In 4 of 16 patients monitored for blood flow insufficiency, the MEP changed intraoperatively. In 2 patients, the changes were attributable to temporary occlusion of the feeding artery (anterior choroidal or lenticulostriate artery): 1 patient had a venous infarction around the internal capsule caused by thrombosis of the draining vein and the other bled intraoperatively from the nidus. In 17 patients, the MEP was monitored to rule out direct injury. In 1 patient, the MEP changed on coagulation of fragile vessels around the nidus in the precentral gyrus; it recovered after coagulation was discontinued. In 1 of 5 patients with MEP changes, the MEP did not recover; permanent hemiparesis developed in this patient because of venous infarction. In 1 of 11 patients subjected to MEP mapping of the motor area, we found translocation to the postcentral sulcus.


CONCLUSIONS
In arteriovenous malformation surgery, MEP monitoring facilitates the detection of blood flow insufficiency and/or direct injury of the corticospinal tract and mapping of the motor area. It contributes to reducing the incidence of postoperative motor paresis.
Ichikawa
Tsuyoshi
T
Department of Neurosurgery, Fukushima Medical University, Fukushima, Japan. ichikawa@fukushima-med-jrc.jp
Suzuki
Kyouichi
K
Sasaki
Tatsuya
T
Matsumoto
Masato
M
Sakuma
Jun
J
Oinuma
Masahiro
M
Kasuya
Hiromichi
H
Kodama
Namio
N
D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001931:Brain Mapping; D002533:Cerebral Angiography / Q000379:methods; D002648:Child; D004569:Electroencephalography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D012189:Retrospective Studies; D055815:Young Adult