Unruptured Intracranial Aneurysms — Risk of Rupture and Risks of Surgical Intervention

Intracranial aneurysms are common. 1 – 6 Autopsy studies have shown that the overall frequency in the general population ranges from 0.2 to 9.9 percent (mean frequency, approximately 5 percent), 5 , 6 suggesting that 10 to 15 million persons in the United States have or will have intracranial aneurysms. These data, in combination with the incidence of aneurysmal subarachnoid hemorrhage (approximately 10 cases per 100,000 persons per year), 7 suggest that most intracranial aneurysms do not rupture. The management of unruptured intracranial aneurysms is controversial 8 – 12 because of a lack of understanding of the natural history of these lesions and the risks of repairing . . .