Anterior Choroidal Artery Infarction with No Abnormalities of Motor Evoked Potentials During Cerebral Aneurysm Surgery -A Case Report-

Motor evoked potentials (MEPs) with somatosensory evoked potentials (SSEPs) have been used to prevent neurological during cerebral aneurysm surgery. This case shows postoperative anterior choroidal artery (AChA) with decreased SSEPs, in spite of preserved MEPs during aneurysm clipping. A 58-year-old man with aneurysm between right internal carotid artery and AChA received aneurysm clipping. During temporal arterial, left tibial SSEPs amplitude decreased by 95% and median SSEPs decreased by 89% of the baseline. SSEPs lasted for 10 minutes and there was no change of MEPs. After operation, mental state changed to drowsy and side weakness occurred. Cerebral angiography showed non-visualized right AChA and brain MRI showed right AChA. MEPs are difficult to be performed continuously because patient movement may interfere with microsurgery raise safety concerns. We suppose that SSEPs are possibly complement of MEPs to take consider the subcortical such as AChA.