Cerebral revascularization, using extra-anatomic bypass grafts of autologous saphenous vein, was performed in three patients to prevent or to compensate for ischemic effects of emergency ligation of a carotid artery. These ligations were required after spontaneous disruption of common carotid arteries in patients with previous irradiation and radical head and neck surgery. External-carotid-to-external-carotid cross-over (submandibular) bypass graft was performed once, and ipsilateral axillointernal carotid bypass grafts twice. The role of infection in carotid artery rupture, the unpredictable nature and different mechanisms of cerebral malfunctions after carotid ligation, technical details of extra-anatomic bypass grafts, and anatomic considerations in the prevention of recurrent infection and bleeding are discussed. A planned approach of cerebral revascularization at the time of ligation appears to be preferable to a fortuitous outcome. Neurological disability and death from cerebral ischemia can be prevented by using extraanatomic bypass vein grafts.