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Microsurgical Clip Obliteration of Middle Cerebral Aneurysm Using Intraoperative Flow Assessment
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Transient Augmentation of Intraoperative Motor Evoked Potentials During Middle Cerebral Artery Aneurysm Surgery

Pritam Gurung1, Yasushi Motoyama2, Tsunenori Takatani3

  • 1Department of Neurosurgery, Nara Medical University, Kashihara, Japan; Department of Neurosurgery, Ohnishi Neurological Center, Akashi, Japan.

World Neurosurgery
|June 16, 2019
PubMed
Abstract

Insights

Transient augmentation of motor evoked potentials (MEPs) during middle cerebral artery (MCA) aneurysm surgery may signal early ischemia. This MEP increase was linked to temporary clip placement closer to the MCA

Area of Science:

  • Neurosurgery
  • Neurology
  • Intraoperative monitoring

Background:

  • Direct open surgery for middle cerebral artery (MCA) aneurysms carries risks of neurological deficit.
  • Intraoperative motor evoked potentials (MEPs) are used to monitor neural function during such procedures.

Purpose of the Study:

  • To investigate the clinical significance of intraoperative motor evoked potential (MEP) augmentation during direct open surgery for MCA aneurysms.
  • To determine the frequency, causes, and associated factors of MEP augmentation.

Main Methods:

  • Retrospective analysis of 134 MCA aneurysm surgeries with intraoperative MEP monitoring (2009-2017).
  • Studied the frequency and causes of MEP augmentation (>50% amplitude increase).
  • Compared patients with and without MEP augmentation regarding clip placement and other factors.

Main Results:

  • MEP augmentation occurred in 9 patients, exclusively after temporary parent artery clipping.
  • Augmentation peaked at 2.4 ± 1.1 minutes post-occlusion (2.6 ± 1.1 times baseline amplitude).
  • MEP augmentation was associated with a smaller distance of the temporary clip from the midline (P = 0.033).

Conclusions:

  • MEP augmentation is likely an early ischemic indicator preceding MEP decrease during MCA aneurysm surgery.
  • Transient MEP augmentation was more common when the temporary clip was placed more proximally on the MCA.
Keywords:
Augmentation of evoked potentialMiddle cerebral artery aneurysmMotor evoked potentialTemporary clipping

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