Decompression of the vertebral artery for bow-hunter's stroke. Case report.

A case of cerebellar infarction induced by repeated neck rotation ("bow-hunter's stroke") is reported. The most likely mechanism is that repeated rotational neck movement brings about thickening of the atlanto-occipital membrane, fixing the vertebral artery in the vascular groove of the atlas. The vertebral artery is thus pinched at the time of neck rotation, leading to thrombus formation. Embolization results in cerebellar infarction. Surgical decompression of the vertebral artery at the level of the atlas in this case relieved the symptoms, and postoperative angiography demonstrated good flow within the vertebral artery even when the neck was rotated. It was not necessary to restrict the patient's neck movement postoperatively.