External carotid endarterectomy: indications, operative technique, and results.

In the presence of chronic internal carotid artery occlusion, the external carotid artery becomes an important source of collateral circulation to the ipsilateral cerebral hemisphere and eye. It not only supplies blood via periorbital collaterals with retrograde flow in the ophthalmic artery, but also may allow emboli to reach the retina or brain. The cul-de-sac or "stump" created by internal carotid artery occlusion may frequently be the source of emboli causing amaurosis fugax or hemispheric transient ischemic episodes. Seven such patients presenting with amaurosis fugax and/or hemispheric transient ischemic episodes were found at operation to have atherosclerotic ulceration or platelet fibrin debris at the carotid bifurcation and the internal carotid artery cul-de-sac. These patients were treated by external carotid endarterectomy with excision and closure of the occluded internal carotid artery cul-de-sac to remove a potential source of stasis and platelet fibrin deposition. A preoperative angiogram and intraoperation photograph demonstrating the typical pathologic findings are presented. The surgical technique emphasizing excision and closure of the internal carotid cul-de-sac is illustrated. Six of the seven patients have remained asymptomatic with a 2- to 28-month follow-up. The importance of considering microembolism as a cause of symptoms in some patients without external carotid artery stenosis is stressed.