Small Intracranial Aneurysms and Subarachnoid Hemorrhage: Is the Size Criterion for Risk of Rupture Relevant?

The current understanding is that small intracranial aneurysms (<7 mm) are not at a significant risk for rupture. However, there have been several published series of rupture and subarachnoid hemorrhage from aneurysms <5 mm. Three cases of intracranial aneurysms rupturing at <3 mm are presented in this paper. Patient age ranged between 38 and 57 years. The aneurysms were located in different parts of the circulation in the brain. This case series highlights that the size criterion alone is not adequate when evaluating patients with unruptured brain aneurysms for observational follow-up or treatment.