Challenging diagnosis of subaxial bow hunter's syndrome presenting with recurrent posterior circulation infarcts: illustrative case.

BACKGROUND: Bow hunter's syndrome (BHS), or rotational vertebral artery (VA) occlusion, is a rare cause of vertebrobasilar insufficiency resulting from dynamic compression of the VA during head rotation. Classically described at the atlantoaxial level with rotational occlusion, subaxial and nonrotational variants exist and can remain underdiagnosed as standard vascular imaging often fails to reveal positional occlusion.

OBSERVATIONS: A 54-year-old man with no vascular risk factors presented with recurrent posterior circulation strokes despite medical management. Conventional imaging identified a left VA occlusion but failed to reveal the cause. Dynamic digital subtraction angiography revealed paradoxical reopening of the left VA with neck extension, confirming BHS at the C6-7 level. The patient underwent direct decompression and anterior cervical decompression and fusion, resulting in restoration of VA flow and clinical stabilization.

LESSONS: This case highlights an underrecognized diagnostic pitfall of BHS through a presentation where static imaging suggested a fixed VA occlusion. Nonrotational variants at a subaxial level may mask positional occlusion. Dynamic imaging should be pursued in patients with recurrent posterior circulation infarcts despite seemingly explanatory static image findings. Recognition of these atypical patterns can help timely intervention to achieve durable prevention of further ischemic events. https://thejns.org/doi/10.3171/CASE2666.