Risk Factors and Preventive Methods of Neuropsychological Dysfunction after Clipping Surgery for Unruptured Cerebral Aneurysms

Abstract

Summary:We evaluated the neuropsychological functions of 105 patients who underwent 108 surgeries for unruptured cerebral aneurysms. All patients completed the Wechsler Adult Intelligence Scale-Revised (WAIS-R) before and one month after surgery. The aneurysms were located mainly in the anterior cerebral artery, middle cerebral artery, or internal cerebral artery. Deep white matter hyper-intensities (DWMH), brain atrophy and cerebral infarction were evaluated using preoperative magnetic resonance imaging (MRI). Brain contusion (large: 10 mm or more in largest diameter; small: smaller than 10 mm), subdural fluid collection (thick: midline shift observed; thin: mass effect observed without midline shift) and cerebral infarction were evaluated on postoperative MRI and/or computed tomography. A decrease of four points or more in the WAIS-R score postoperatively was interpreted as deterioration.Although there was no statistical difference between the preoperative and postoperative WAIS-R scores, 25 of 108 surgeries (23%) showed deterioration of the WAIS-R score postoperatively.Brain contusion on MRI was observed in 15 surgeries (large: 7; small: 8), and six of those surgeries (40%) showed deterioration of the WAIS-R score. Deterioration of the WAIS-R score was observed more frequently in patients with large brain contusion (4 of 7, 57%) than in those without brain contusion (19 of 93, 20%) (p 0.05). Brain contusion occurred more frequently in patients with moderate or severe DWMH (5 of 23, 22%) than in those without DWMH (2 of 43, 5%) (p 0.05), and in patients with ACoA aneurysm (5 of 26, 19%) than in those with MCA aneurysm (1 of 33, 3%) (p 0.05). Although large brain contusion was observed postoperatively in patients with aneurysms localized to the ACoA operated through the pterional approach, damage was not apparent in patients operated with an interhemispheric approach. Subdural fluid collection was observed after 14 surgeries (thick: 5; thin: 9), and four of those patients (29%)