Does a Craniotomy for Treatment of Unruptured Aneurysm Affect Cognitive Function?

The surgical procedure used to treat an unruptured intracranial aneurysm (UIA) has controversial effects on cognitive function. From January 2010 through December 2012, we enrolled patients who underwent surgical clipping for a UIA. Patients were tested within one week prior to surgery and again postoperatively (6.8 ± 2.3 days) using a neuropsychological battery comprising the Mini-Mental State Examination, the Trail Making Test (TMT), the Frontal Assessment Battery (FAB), and Raven's colored progressive matrices (RCPM). Differences between preoperative and postoperative test scores for each examination were analyzed across individuals. In an additional subgroup analysis, patients were grouped according to age (< 65 or ≥ 65 years), the largest dimension of the aneurysm, the location of the aneurysm (i.e., anterior communicating artery, internal carotid artery, or middle cerebral artery) and operation duration. Paired student's t-tests were used to examine potential differences between groups. Two-tailed P-values < 0.05 were considered significant. Seventy-one patients were included in the analysis. The surgical procedure used to correct a UIA resulted in significant changes in neuropsychological scores. After the procedure, the TMT-A score declined significantly, whereas the FAB and RCPM scores were significantly improved. In the subgroup analysis, a significant deterioration in TMT-A score was observed in older patients and those with larger aneurysms, anterior communicating artery aneurysms and longer surgeries. Our findings, therefore, indicate that the surgical procedure to correct a UIA affects cognitive function. Older patients and those with large aneurysms, anterior communicating aneurysms, and long operations represent the high-risk groups.