Surgical treatment of paraclinoid and ophthalmic aneurysms.

Paraclinoid aneurysms include those arising from the ophthalmic segment and from the distal cavernous carotid artery or clinoid segment. Three aneurysm variants originate from the ophthalmic segment: ophthalmic artery, superior hypophyseal artery, and dorsal types. Clinoidal segment aneurysms arise from the carotid artery in the interval between the carotid oculomotor membrane proximally and the dural ring distally, and include anterior-lateral and medial variants. With proper exposure and a firm understanding of the parasellar osseous, dural, and vascular anatomy, most paraclinoid aneurysms are occluded with low risk to the brain or visual apparatus.