Atlanto-axial dislocation associated with anomalous single vertebral artery and agenesis of unilateral internal carotid artery.

We report a case of an anomalous single midline vertebral artery (VA) in a case of atlanto-axial dislocation (AAD). The left VA coursed in the midline at craniovertebral junction as there was no right VA. The left internal carotid artery was also not formed. This was a case report of a 34-year-old male patient who presented with features of high cervical myelopathy. On evaluation, he had fixed AAD. There was inadvertent intra-operative VA injury, which was sealed to control the brisk bleeding to require stenting ultimately. Patient did not survive and expired after 5 days due to brain edema secondary to compromised anomalous intracranial circulation.