Abstract
A 69-year old woman presented with a history of surgical clipping of an unruptured right middle cerebral artery (MCA) aneurysm 13 years before. Angiography revealed no residual aneurysm just after the operation. She presented to our hospital for the first time in 13 years. Computed tomographic angiography revealed a recurrent aneurysm from which M2 branches were distributed. We planned direct surgical clipping with preparation for surgical revascularization. The ipsilateral superficial temporal artery (STA) was sacrificed at the time of the first operation; therefore, we used the contralateral STA graft for a temporary bypass. Blood flow to this vessel was supplied by the radial artery via an arterial line. Intraoperatively, we monitored motor evoked potential (MEP) amplitude. The MEP amplitude was lowered to 23% of the control level 25 minutes after applying a temporary clip to M1 and M2 segments. We clipped the aneurysm and confirmed complete clipping by obtaining an indocyanine green (ICG) angiogram. The MEP amplitude recovered within 30 min after removing the temporary clips.
After operation, she experienced a transient right hemiparesis, which resolved within 12 hours. We propose that this method could be an alternative treatment strategy if, for whatever reason, the ipsilateral STA is not available for bypass surgery.
