[Cervical myelopathy caused by bilateral vertebral artery compression]

We report a rare case of myelopathy caused by compression of the upper cervical cord by the bilateral anomalous vertebral arteries. A 49-year-old man had dragged his right foot for 4 years. He also complained of a tingling sensation in his right arm and occipitalgia. Neurological examination disclosed right hemiparesis, hypalgesia in the right half of the body and hypertonicity of the lower extremities. MRIs showed a flow void area which compressed and distorted the spinal cord bilaterally at the level of the atlas. A vertebral angiogram showed that the bilateral vertebral arteries had pierced the dura matter under the posterior arch of the atlas, turned upward and laterally in the vertebral canal, making vascular loops at the level of the atlas. 3D CT angiography showed the loops convex medially in the anterior part of the vertebral canal. With these findings, we diagnosed the patient as suffering compression of the cervical cord by the bilateral anomalous vertebral arteries. Suboccipital craniectomy and C1 laminectomy were performed. When the dura mater was opened, the dorsolateral aspect of the spinal cord was found to be compressed and indented markedly by the vertebral arteries. To decompress the spinal cord, the vertebral arteries were retracted dorsolaterally by means of Gore-tex tape and anchored to the spinous process of the axis. Postoperatively, his neurological symptoms improved. Postoperative MRIs showed that the spinal cord was decompressed and had recovered its contour. A review of the literature revealed that only 3 such cases as this one have been reported. The clinical features of these rare cases are nonspecific myelopathy and concomitant occipitalgia or neck pain. The main cause of this rare entity seemed to be the compression of the vertebral artery through its course when it enters the vertebral canal between the atlas and the axis.