Cerebellar infarction originating from vertebral artery stenosis caused by a hypertrophied uncovertebral joint.

We report a case of cerebellar infarction originating from vertebral artery stenosis caused by a hypertrophied uncovertebral joint. A 38-year-old man presented with sudden onset of headache, dizziness, and dysarthria. The magnetic resonance imaging scan of the brain revealed acute infarction in the right cerebellar hemisphere in the territory of the posterior inferior cerebellar artery (PICA) and superior cerebellar artery (SCA). Magnetic resonance, 3-dimensional computed tomographic, and conventional angiography revealed severe right vertebral artery stenosis by extrinsic compression of the hypertrophied right C5-C6 uncovertebral joint. The diagnosis was acute cerebellar infarction, which was probably caused by embolism from the right vertebral artery stenosis that was caused by the hypertrophied C5-C6 uncovertebral joint. C5-C6 anterior discectomy and fusion were performed together with direct uncovertebral joint decompression. Postoperative 3-dimensional computed tomographic angiography revealed improvement in antegrade filling in the right vertebral artery. The imaging findings for this patient and the pathogenesis of cerebellar infarction for our patient are discussed.