Bilateral dissection of the internal carotid artery at the base of the skull due to blunt trauma: incidence and severity.

ABSTRACT

Between January 1, 1992 and December 31, 1996, a total of 1095 head trauma vicims were admitted in our intensive care unit. If CT scans demonstrated ischemic brain lesions, arteriography to visualize supraaortic vessels was performed. Carotid artery dissection was observed in ten patients (0.91%) and was bilateral in eight patients (0.73%). In the bilateral carotid artery dissection (BCAD) group, there were five women and three men, with a mean age of 35.2 years (range 17 to 54 years). Injuries resulted from traffic accidents in seven patients and a fall in one patient. Upon admission, six patients presented with alteration of consciousness and three with hemiplegia or hemiparesia, associated with aphasia in two cases. In two other cases, hemiplegia occurred 24 hr and 13 days after the accident. All patients had brain infarction, which was unilateral in five cases and bilateral in three cases. The severity of lesions was graded on the basis of arteriographic findings as follows Type I, wall involvement without significant stenosis or dilation; Type II, arterial dissection with stenosis >70% (Type IIA) or dilatation >50% (Type IIB) and the normal diameter of the proximal or distal internal carotid artery; and Type III, thrombosis of the internal carotid artery. Lesions were asymmetrical in six patients, including two with Type II and III lesions and four with Type I and II lesions, and symmetrical in two patients, including one with bilateral Type III lesions and one with bilateral Type II lesions. Surgery was performed in two patients with Type II lesions, including one case associated with contralateral carotid thrombosis. The intrapetrous carotid artery was exposed by an ear-nose-throat (ENT) surgeon and repaired by interposition grafting. Follow-up in these two surgical cases was 28 and 31 months. In the remaining six cases, medical treatment was performed. Outcome in nonsurgical cases was variable death in two cases at 31 and 43 days after the accident, severe permanent hemiplegia in two cases, and minimal or no sequels in two cases. Following blunt trauma, arteriography of supraaortic vessels should be performed to detect BCAD in any patient with immediate or delayed neurologic symptoms that cannot be explained by CT-scan findings. To better understand the natural course of these lesions and define the indications for surgery, we propose a three-grade classification according to arteriographic findings. If surgery is undertaken, vein grafting should be performed following resection of the carotid artery lesions.