How to treat incidental cerebral aneurysms: a review of 139 consecutive cases.

BACKGROUND Together with current advances in neuroimaging techniques, the chance of incidental discovery of unruptured cerebral aneurysms has increased and the selection of their appropriate management remains controversial. To provide current data about management results of patients with incidental cerebral aneurysms, we have made a retrospective review of 139 consecutive patients treated either by surgical or conservative means. METHODS The surgical indication for each patient was decided, carefully considering several factors respectively, including the surgical difficulty, aneurysm size, patient's age, and medical condition. RESULTS Forty-nine patients were managed conservatively. Eight (16%) of those conservatively managed patients had intracranial hemorrhage due to aneurysm rupture during the follow-up period (mean, 4.3 years). Seven of these eight patients died from a fatal subarachnoid hemorrhage (SAH). The follow-up data showed that the mean size of aneurysms with late hemorrhage was significantly larger than that of aneurysms without subsequent rupture. It was also confirmed that none of the 26 tiny aneurysms smaller than 4 mm in diameter had ruptured. Ninety patients harboring 119 incidental aneurysms less than 25 mm in diameter underwent surgery. There was no surgical mortality or morbidity in this series. CONCLUSIONS These excellent surgical results were presumably achieved due to the strict patient selection. In respect to the size of aneurysms, it seems to be justified to recommend surgery for patients with aneurysms larger than 5 mm in diameter.