Ｇｙｒｕｓ ｒｅｃｔｕｓの一部吸引にて記憶障害を生じた未破裂前交通動脈りゅうの１手術例

Abstract

We have operated on 21 patients with an unruptured anterior communicating aneurysm by the pterional approach. Partial resection of the gyrus rectus was performed in 10 patients (44%). Of these patients, 1 patient had postoperative memory disturbances. We present this patient and discuss the responsibility of the gyrus rectus for memory deficit. A 61-year-old right-handed woman underwent MRI for the evaluation of chronic headache and was found to have an anterior communicating aneurysm. The aneurysm was 8 mm in size and arose from the junction of the anterior communicating artery and the left A2 segment. The fundus of the aneurysm was buried in the right gyrus rectus. A right pterional approach with partial resection of the gyrus rectus was employed. The aneurysm was successfully clipped and the postoperative course was uneventful. Postoperative CT showed only postoperative changes and postoperative MRI demonstrated only a small discrete right gyrus rectus lesion. However, the patient complained of memory disturbances on the third postoperative day. Neuropsychological tests performed 1 month after surgery revealed typical anterograde amnesia. Our case suggests that the gyrus rectus resection may be responsible for postoperative memory deficits. We propose a possible mechanism of our patient's amnesia: the gyrus rectus resection may result in disconnection of the pathway between the basal forebrain and the hippocampal region or the cortex, depriving these areas of cholinergic innervation.