High-flow bypass surgery for a large cavernous internal carotid artery aneurysm associated with persistent primitive...

Giant cavernous internal carotid artery (ICA) aneurysms present with therapeutic challenges, especially if associated with a persistent primitive trigeminal artery (PPTA). Although flow diverters (FDs) are commonly used, the PPTA can maintain collateral inflow to the aneurysm sac, preventing complete thrombosis.

A 74-year-old woman presented with progressive oculomotor nerve palsy and visual decline. High-flow external carotid-middle cerebral artery bypass with distal ICA occlusion beyond the aneurysm was performed. The bypass remained patent without infarction, and partial aneurysm thrombosis occurred, whereas PPTA flow was preserved.

This case emphasizes the importance of individual microsurgical strategies if FD treatment may be ineffective due to complex embryonic vascular anatomy.