The impact of size and location on rupture of intracranial aneurysms

OBJECTIVE: For effective management of patients with unruptured intracranial aneurysms, prognostic criteria for rupture, of which aneurysm size, location, and multiplicity are key factors. The aim of this study is to determine the correlation between the aneurysm size, location, and multiplicity, and their effect on aneurysmal rupture. MATERIALS AND METHODS: Eighty one patients with diagnosis of intracranial aneurysms were managed at our center from January 2008 through July 2011. The characteristics of aneurysms, such as size, location, multiplicity, and presentation were retrospectively reviewed from their charts and radiological findings. RESULTS: Eighty one patients harboring 104 aneurysms were diagnosed, of them 45 were males (55.5%) and 36 were females (44.5%). Seventy-six patients (94%) presented with subarachnoid hemorrhage (SAH) due to ruptured aneurysm. Thirty-three patients who were presented with SAH (43%) had their ruptured aneurysm located at the anterior communicating artery with a mean size 5.8 mm. Most of the small (<7 mm) ruptured aneurysms were located at the anterior communicating artery, distal anterior cerebral arteries, posterior communicating arteries, and internal carotid artery bifurcation (51%, 13%, 11%, and 11%), respectively. There were 24 small unruptured aneurysms, 10 of them (42%) located at the middle cerebral arteries, while only 2 of them (8%) located at the anterior communicating artery. CONCLUSIONS: The aneurysm size and location play a substantial role in determining the risk of rupture. The most common location of rupture of small aneurysms was the anterior communicating artery, while the middle cerebral artery was the commonest site for small unrupured aneurysms.