2011 年 24 巻 1 号 p. 7-11
Bow hunter's syndrome is a rare cause of vertebrobasilar insufficiency, which results from mechanical compression of the vertebral artery (VA) upon neck rotation. We report a68-year-old woman who complained of faintness when she turned her head to the left. Carotid Doppler ultrasonography demonstrated occlusion of the right VA and a post-stenotic pattern in the left VA flow. Stenosis of the left VA was suspected, but it was difficult to evaluate the blood flow of the left VA after neck rotation to the ipsilateral side. Therefore, we tried transcranial color- coded duplex sonography (TCCS) through the foramen magnum window to observe the intracranial VA. With the neck in a neutral position, the flow in the left VA was normal (peak systolic velocity : 70.7 cm/s), whereas its flow shape changed to a post-stenotic pattern when the neck was rotated45degrees to the left. Moreover, the peak systolic velocity in the left VA decreased to 32.4 cm/s after neck rotation to the end range. Digital subtraction angiography demonstrated that the left VA compression was due to an osteophyte at the C4 level when the patient turned her head to the left. In patients with bow hunter's syndrome, VA stenosis or occlusion may occur on the side ipsilateral to that of neck rotation. In cases where it is difficult to observe the VA by carotid ultrasonography, TCCS through the foramen magnum window may be useful for diagnosis of bow hunter's syndrome.