Classification and Surgical Treatment of Paraclinoid Aneurysms

ABSTRACT

Paraclinoid aneurysms arose from the proximal internal carotid artery between the site of emergence of carotid artery from the roof of the cavernous sinus and posterior communicating artery. Surgery of these aneurysms presents special difficulties because of its complicated osseous, dura, and neurovascular structures;sella turcica, cavernous sinus, optic nerve. The clinical and radiological characteristics in twenty-seven patients with the paraclinoid aneurysms were reviewed and classified into four subgroups according to their branch of origin in this segment;1) carotid cave aneurysm(2 cases), 2) ophthalmic artery aneurysm(11 cases), 3) superior hypophyseal artery aneurysm(11 cases), 4) proximal posterior carotid artery wall aneurysm or global type aneurysm(3 cases). Surgery required orbital unroofing and removal of anterior clinid process with release of dural ring. To provide easy proximal control, exposure of cervical carotid artery was helpful in some cases. Preoperative balloon occlusion testing was man datory. Outcomes were considered as good to fair in 19 patients, poor in five, and three patients died. The patients who had poor results were poor preoperative status-four were grade IV, one was grade II(Hunt-Hess grade). The causes of death were premature rupture(2 cases) and extensive vasospasm(1 case). Preoperative classification of these lesions provides excellent correlation of operative findings and surgical preparation to expose the proximal part of internal carotid artery.