Dynamic vertebral artery recanalization as a cause for recurrent posterior circulation thromboembolic stroke: illustrative case.

Background: Posterior circulation strokes comprise one-fourth of ischemic strokes and can arise from many causes. One rare etiology is transient occlusion of the vertebral artery (VA) with head rotation due to an osteophyte, termed bow hunter's syndrome. The authors present the case of recurrent thromboembolic posterior strokes secondary to transient reopening of an osteophyte-occluded VA.

Observations: A 71-year-old man presented with dizziness and visual changes with a history of prior cervical fusion and myocardial ischemia, controlled with Plavix and aspirin. CT angiography of the neck revealed osteophyte occlusion of the right VA at C4, and MRI revealed a right posterior cerebral artery (PCA) infarct. The patient was discharged on Plavix and aspirin but returned 5 months later with worsening dizziness and visual changes. MRI revealed a new left PCA infarct, leading to repeat angiography. Movement of the head during the procedure recanalized the occluded VA from before. This prompted a diagnosis of thromboembolic stroke resulting from the reopening of the occluded VA with various head movements.

Lessons: This case demonstrates the utility of dynamic cerebral angiography due to the ability to manipulate head position while visualizing blood flow. Despite the invasive nature of the procedure, it helped improve diagnostic accuracy and identify a rare vascular lesion. https://thejns.org/doi/10.3171/CASE25133.