Intracranial aneurysms: size, risk of rupture, and prophylactic surgical treatment.

Intracranial saccular aneurysms frequently cause devastating neurologic injury when they rupture. With recent improvements in diagnostic imaging, however, an increasing number of aneurysms are now diagnosed in the unruptured state. Controversy exists regarding the appropriate management of these lesions. We have retrospectively examined a group of 86 patients from Connecticut with 104 intracranial aneurysms to determine whether small (less than 10 mm in greatest diameter) aneurysms have potential for rupture, and whether there is a role for prophylactic surgical therapy for these unruptured aneurysms. The majority of ruptured and unruptured aneurysms in the series measured less than 10 mm in greatest diameter. Out of a total of 82 patients who underwent surgical therapy, 44 had surgery for unruptured aneurysms. The major surgical morbidity in this group was 2%. We conclude that surgical therapy for small unruptured intracranial aneurysms may be beneficial since these lesions likely have substantial potential for rupture and because surgical treatment carries an acceptable risk.