抄録
We evaluated the clinical features of basal forebrain amnesia caused by obstruction of the perforating artery branching from the anterior communicating artery (A com a.) after clipping of the A com a. aneurysm. Five out of 80 (6.2%) patients who underwent clipping of the aneurysm located at the A com a. using an interhemispheric approach presented basal forebrain amnesia after operation. The course of symptoms was divided into 3 types. The severe type manifests amnesia, disorientation, confabulation, restlessness, insomnia, and wandering for several days after surgery and gradual release from these symptoms but mild amnesia in a few months. The moderate type represents amnesia, disorientation and restlessness, but has recovery without any neurological deficit in a month. The mild type shows transient amnesia for a few weeks.
The severe type included 3 patients whose CT tended to demonstrate focal infarction at the subcallosal area. The moderate and mild type included 1 patient, whose CT revealed no infarction. The patients in the severe type were able to return to previous work or lifestyle, although evocation of long-term episodic memory was somewhat disturbed.
The cause of obliteration of the perforating artery, mainly the subcallosal branch, during surgery was considered as follows: stretching the perforating artery adherent to the rear of the dome after clipping, trapping of the A com a., and a difficulty in confirming patency of the perforating artery running behind the large dome or broad neck, especially when rupture occurred during operation. Therefore, it is important to pay as much attention as possible to preserve patency of a larger perforating artery such as the subcallosal branch during clipping of A com a. aneurysm.
