抄録
Ventral paraclinoid carotid aneurysms were clipped through the contralateral pterional approach in 3 patients. In all the patients, the superior hypophyseal artery arose from the inferomedial aspect of the internal carotid artery just proximal to the aneurysm. These findings strongly support Day's view that ventral paraclinoid carotid aneurysms arise from the distal crotch of the superior hypophyseal artery. The description “superior hypophyseal artery aneurysm” is also proposed by Day instead of the terminology such as ventral carotid, infraophthalmic and infrachiasmal aneurysm and others.
In the present cases, 2 patients (Case 1, 2) had unruptured aneurysms incidentally found, while Case 3 had ruptured carotid-ophthalmic aneurysm that was managed in acute stage of subarachnoid hemorrhage. These aneurysms arose from the internal carotid artery of its inferomedial aspect opposite to the origin of the ophthalmic artery. The aneurysmal necks in the present cases were smaller than 7 mm in size, and found just posterior to the anterior wall of the sella turcica on the lateral view of the carotid angiogram. In contralateral pterional approach, dissection of aneurysms in the prechiasmatic cistern is easy and neither resection of the skull base nor retraction of the optic nerve is necessary. Even in a patient with pre-fixed chiasma (Case 2), the aneurysm was clipped without difficulty. Thus superior hypophyseal artery aneurysms with small necks are good indications for contralateral pterional approach, which is less invasive to the optic nerve.
