A Juvenile Case of Bow Hunter's Syndrome Caused by Atlantoaxial Dislocation with Vertebral Artery Dissecting Aneurysm

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. 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. 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.