Role of head position Through a review of the literature, Thompson et al16 reported that neck surgery was a significant risk factor for stroke, with an incidence of 4.8%. However, they found an incidence of only 0.2% in their own cases. Several reviews and reports have suggested that excessive rotation or extension of the head may be a vascular risk factor for perioperative stroke. Blood flow was measured with stable xenon CT before and after intravenous administration of acetazolamide. For vasodilatation stimulation blood flow was poorly increased in brain tissue sites (indicated by arrows) with impaired cerebrovascular reserve. This assumption is confirmed by the above-mentioned nuclear magnetic study of subcranial anatomical changes17 and by transcranial Doppler ultrasound studies showing that head hyperextension may lead to decreased cerebral blood flow.18 This is also supported by a case report of brainstem evoked potentials19 and by the beauty parlor stroke syndrome. In salon stroke syndrome, symptoms of vertebrobasilar ischemia are associated with head hyperextension during hair washing in the salon.20Grundy et al19 reported this role of head position by illustrating that her team found a loss of midbrain evoked responses in posterior cranial recess surgery, which was clearly associated with head rotation, and believed that head rotation was a vascular trigger.