Commentary

In this retrospective review of 61 patients, the authors propose a new classification scheme for aneurysms arising from the ophthalmic segment of the internal carotid artery. The aneurysms are classified into four variants. Type Ia is a classic ophthalmic artery aneurysm. Type Ib arises more distally on the supraclinoid ICA but not on the origin of the ophthalmic artery. Type II is an inferolateral ICA aneurysm. Type IIIa arises from the medial wall of the C5 segment and has been described as an anteromedial or cave aneurysm. Type IIIb would probably be classified as a cave or cavernous aneurysm. Type IV aneurysms are similar to type II but are much larger and enlarge the distal dural ring. They may be partially in and out of the subarachnoid space. The authors are an experienced team and have an excellent reputation for performing outstanding work and research in neurovascular surgery.

The authors indicate that they performed thin-section CT with bone windows of the clinoidal region to determine whether calcification was present on the aneurysmal wall. More recently, we have used CT angiography to delineate the anatomy of these aneurysms and their relation to the clinoid. This modality would also clarify whether type III aneurysms arise above or below the diaphragm sella. Only time will tell whether this classification scheme will be used routinely by neurovascular surgeons. However, it represents an alternative to mere description of the anatomical location of aneurysms and may be easy to remember and apply. The authors should be congratulated for their work.