Abstract
We studied cases of 60 patients with 64 infraclinoid aneurysms surgically treated and classified these aneurysms into 3 groups based on surgical findings. Group I was infraclinoid aneurysms located distal to the dural ring and projected ventromedially. Group IA are distal to the origin of ophthalmic artery and Group IB are proximal to the artery. These Group I aneurysms originated below the level of the anterior clinoid process on the lateral view of carotid angiogram but these are truly subdural aneurysms and may cause subarachnoid hemorrhage. Group II aneurysms are located between the distal (dural) ring and the proximal ring. Group IIA are occurred at the medial surface of the internal carotid artery and Group IIB are occurred at the lateral surface. Those of Group III are central to the proximal ring and projected laterally. Group III aneurysms are genuine intracavernous aneurysms. These classifications are extremely useful for selection of operative candidates and surgical procedures.
