Extracranial carotid artery aneurysms.

Aneurysms of the extracranial carotid arteries are uncommon vascular lesions. During the period 1976 to 1986 we encountered 18 extracranial carotid aneurysms in 14 patients. The aneurysms were atherosclerotic (12 in 9 patients), congenital (3 in 2 patients), mycotic (1) and secondary (false aneurysms) after previous carotid surgery (2 in 2 patients). The patients presented with neurological symptoms (11) or a pulsating mass in the neck (2). In one patient the aneurysm was detected accidentally during angiography. From this study it became clear that "carotid aneurysm" is not a well defined entity. The "normal" configuration of the carotid bulb with its usually larger diameter, is in part a cause of the problem of definition. A recently described technique for predicting normal vessel diameters in stenosing lesions of the carotid arteries was retrospectively applied to all our patients with aneurysms. With these measurements, made on standard preoperative angiograms, it was possible to quantify the degree of dilatation, and confirm the diagnosis of aneurysm. Eleven of the 14 patients were operated on without mortality, no neurological deficits were seen as a result of the operation and minimal morbidity occurred in six patients. From this study we conclude that surgical correction of accessible carotid artery aneurysms is a relatively safe procedure and these lesions should be operated on irrespective of symptoms. This is the first report that gives clear guidelines for measuring dilatation of the extracranial carotid arteries and based on these guidelines we suggest criteria for the discrimination between physiological dilatation and pathological aneurysm formation, the latter condition being an indication for operation.