BACKGROUND: Bow hunter's syndrome (BHS) is caused by posterior circulation 
insufficiency that results from the occlusion or compression of the vertebral 
artery (VA) during neck rotation. Owing to its rarity, there is no guideline to 
support the decision of selecting a conservative or a surgical approach. 
Management of BHS is dependent on each patient.
CASE DESCRIPTION: A 13-year-old girl presented with transient visual 
disturbance, hypoesthesia, and paralysis of the left side of the body. Magnetic 
resonance imaging revealed an acute cerebral infarction in the right thalamus, 
and magnetic resonance angiography demonstrated occlusion of the right posterior 
cerebral artery and dilation of V3 of the left VA. Digital subtraction 
angiography revealed a left VA dissecting aneurysm at V3 and left VA occlusion 
at the level of C1-C2 during neck rotation to the right. A dynamic x-ray 
suggested atlantoaxial joint instability, and three-dimensional computed 
tomography revealed aplasia of C1 lamina and atlantoaxial rotatory dislocation. 
BHS with left VA dissecting aneurysm caused by atlantoaxial rotatory dislocation 
was diagnosed. We performed C1-C2 posterior fusion by the Goel-Harms technique. 
Stroke did not recur, and computed tomography angiography obtained 8 months 
postoperatively demonstrated a decrease in the dissecting aneurysm.
CONCLUSIONS: To our knowledge, this is the first case of BHS with VA dissecting 
aneurysm and aplasia of C1 lamina. Based on this case, we suggest that C1-C2 
posterior fusion is effective for BHS with VA dissecting aneurysm.