Giant intracranial aneurysm

Intracranial aneurysms with a maximum diameter of at least 25 mm are classified as giant. They make up a small fraction of all aneurysms but carry a poor natural history, presenting with subarachnoid hemorrhage, thromboembolism or mass effect on nearby nerves and brain.

Their size, wide necks, intraluminal thrombus and incorporated branches often make simple clipping or coiling impossible. Microsurgical strategies include clip reconstruction, cerebral revascularization (bypass) combined with clipping, and bypass with parent artery occlusion or trapping. Endovascular flow diversion is another option for some locations.

Outcomes are typically reported with the modified Rankin Scale, and because series are small and single-center, strategy comparisons are usually observational.