A case of embolic infarction originating from extracranial vertebral artery stenosis by cervical spondylosis at C5/6: its pathogenesis and surgical treatment

We report a case of right brainstem and cerebellar infarction induced by head rotation. The infarction was due to an artery to artery embolism originating from extracranial vertebral artery stenosis resulting from C5-6 cervical spondylosis. A-64-year-old man with cervical spondylosis experienced swallowing difficulty and vertigo while eating dinner. Neurological examination at admission indicated lateral medullary syndrome (Wallenberg syndrome). MRI (FLAIR) revealed multiple high-intensity signal areas in the right lateral medulla and the cerebellar hemisphere in the territory of the posterior inferior cerebellar artery (PICA). Right vertebral angiogram demonstrated marked stenosis in the neutral position and occlusive changes with head rotation to the right (30 degrees) at C5-6. Rotation induced substantially delayed filling of the right vertebral artery. To remedy this, we resected the osteophyte, fused the uncovertebral joint and connective tissue adhering tightly to the right vertebral artery at C5-6 level, and unroofed the transverse foramens at C5 and C6. Post-operative angiogram confirmed the disappearance of marked stenosis and improved antegrade filling of the right vertebral artery. In the present report, the pathogenesis and surgical treatment of this particular case are discussed.