Abstract
The authors describe a 60-year-old female patient in whom profound ischemia due to temporary occlusion of the internal carotid artery (ICA) was clearly detected during surgery for complex ICA aneurysms by motor evoked potential (MEP). Repeated temporary occlusion of the ICA shortened the latency of MEP amplitude reduction and enhanced its degree. Reopening of the ICA immediately recovered MEP amplitude. Somatosensory evoked potential (SEP) did not show any significant change throughout the surgery. After surgery, she developed transient hemiparesis, which was closely related to transient.reduction of MEP amplitude during surgery. Although blood flow threshold and mechanism for MEP amplitude reduction have not been clarified, the findings strongly suggest that MEP monitoring can also be a sensitive, reliable modality during temporary parent artery occlusion.
