SURGERY FOR PARACLINOIDAL CAROTID-ARTERY ANEURYSMS

Aneurysms arising from the proximal carotid artery between the roof of the cavernous sinus and the origin of the posterior communicating art ery pose conceptual and technical surgical problems with regard to acq uisition of proximal control and safe intracranial exposure. Over the past 3 1/2 years, 89 patients with paraclinoidal aneurysms have been t reated at the University of Texas Southwestern Medical Center. Thirty- nine (44%) of these patients presented with subarachnoid hemorrhage. A total of 149 aneurysms and six arteriovenous malformations have been identified in this patient group such that 38 (43%) of the patients su ffered multiple vascular anomalies. Temporary artery occlusion has bee n employed during operation in 48 cases (54%), permanent carotid arter y occlusion in four (4%), and hypothermic circulatory arrest in two (2 %). Twenty-two patients harbored giant aneurysms, seven of which had r uptured. Outcome was considered good in 77 patients (86.5%), fair in e ight (9%), and poor in three (3%); one patient died. This concentrated experience permitted a practical anatomical grouping of aneurysms int o three types: carotid-ophthalmic artery aneurysms with a superior or superomedial projection (44 cases); superior hypophyseal aneurysms wit h a medial or inferomedial projection (26 cases); and proximal posteri or carotid artery wall aneurysms projecting posteriorly or posterolate rally (19 cases). Despite the fact that paraclinoidal aneurysms often disobey the traditional teachings of aneurysm development, having no v essel of origin or clear hemodynamic cause, this practical grouping ha s allowed individualized and focused operative approaches unique to ea ch aneurysm projection with good visual function and outcome in most p atients.