Bow hunter's syndrome due to an embolic mechanism: illustrative case.

Background: Bow hunter's syndrome (BHS) is an uncommon cause of vertebrobasilar ischemic stroke, which results from occlusion or injury to the vertebral artery (VA) during neck rotation. Although hemodynamic insufficiency is the predominant underlying mechanism of this entity, BHS due to embolic mechanisms is rare. The authors report a case of BHS characterized by repeated posterior circulation embolism and present some considerations of BHS with an embolic mechanism.

Observations: A 57-year-old man suffered from repeated embolic stroke in the posterior circulation. Digital subtraction angiography revealed caliber irregularity of the V3 segment of the left nondominant-side VA, which occluded when the neck rotated to the right side. The patient was diagnosed with BHS with an embolic mechanism due to endothelial damage caused by osteophytes at the C1 foramen transversarium. After C1-C2 fusion surgery, the patient never experienced the recurrence of stroke. According to a literature review, BHS due to embolic mechanisms tends to occur in young male adults, manifesting as recurrent stroke in the posterior circulation. Involvement of the nondominant-side VA can cause BHS with an underlying embolic mechanism.

Lessons: BHS due to an embolic mechanism should be considered as a differential diagnosis if patients have repeated embolic strokes in the posterior circulation.