A case of anterior choroidal artery occlusion test under MEP monitoring for a recurrent internal carotid artery-anterior choroidal artery bifurcation aneurysm clipping.

A 59-year-old female with recurrent Anterior Choroidal Artery (AchA) aneurysm was elected for surgery at our institution through a standard pterional approach. Two thin perforating branches were found to origin from the dome of the aneurysm during operation, and therefore complete aneurysm clipping preserving these branches was not feasible. These perforating branches were temporarily occluded under motor-evoked potential (MEP) monitoring. The MEPs remained stable during 10 min of temporary clipping, and we concluded that these branches could be sacrificed, and therefore neck clipping was performed occluding these tiny AchA perforators. Although postoperative magnetic resonance imaging with diffusion-weighted images showed ischemic signs in left AchA territory after the operation, the patient remained asymptomatic and was discharged home with mRS 0.