Bilateral bow hunter's syndrome at the craniocervical junction: illustrative case.

backgroundRotational vertebrobasilar ischemia, also known as bow hunter's syndrome (BHS), is an underrecognized cause of posterior circulation stroke. Fewer than 200 cases have previously been documented, with most involving unilateral dynamic compression of the vertebral artery by adjacent bony structures that are subsequently treated with surgical decompression. OBSERVATIONS: The authors report a case of bilateral BHS involving the craniocervical junction in a 37-year-old patient who presented with multiple posterior circulation ischemic events. Dynamic angiography revealed that his left vertebral artery was occluded by head turn to the right, and his right vertebral artery became stenotic during head turn to the left. The patient had multiple anomalies of the craniocervical junction; however, no direct bony vertebral artery compression was seen. Therefore, occiput-C3 fusion was performed to prevent dynamic vertebral artery kinking on neck rotation and thus further stroke. LESSONS: BHS can present with bilateral vertebral artery kinking in rare cases. Particularly at the craniocervical junction, vertebrobasilar ischemia can occur in the presence of tortuous vertebral artery anatomy and vertebral anomalies without obvious bony compression. Dynamic catheter and CT angiography are essential diagnostic studies, and occipitocervical fusion can be useful if no direct bony compression is identified. https://thejns.org/doi/10.3171/CASE26286.