Repeated basilar tip occlusion associated with atlantooccipital assimilation: A case report.

We describe an 82-year-old man with multiple cerebral infarctions due to vertebral artery dissection associated with an atlanto-occipital assimilation. Despite multiple thrombectomies and antithrombotic therapy changes, the patient developed thrombosis and recurrent infarction, due to mechanical damage to the vertebral artery possibly associated with abnormal cervical spine motion from atlanto-occipital assimilation. This case highlights the rare association between atlanto-occipital assimilation and stroke and the importance of considering structural abnormalities for stroke management.