A Case of Subarachnoid Hemorrhage Due to Ruptured Lateral Spinal Artery Aneurysm

The lateral spinal arteries (LSA) serve as an important collateral pathway when there is occlusion of the vertebral artery (VA) or posterior inferior cerebellar artery (PICA). We report a case of subarachnoid hemorrhage (SAH) due to a ruptured LSA. A 69-year-old female was admitted to our department due to sudden posterior cervical pain. Computed tomography (CT) of the head showed SAH in the craniocervical junction with intraventricular hemorrhaging. The digital subtraction angiography (DSA) showed the LSA, with an aneurysm, which serves as collateral circulation into the PICA. Endovascular treatment was performed and the proximal parent artery was occluded because it was not possible to navigate a microcatheter close enough to the aneurysm. However, after 18 days, the DSA showed new collateral circulation and the aneurysm was present again. We decided to perform direct surgery to remove the aneurysm after which the patient made a good recovery. Ruptured aneurysms of the LSA are rare, and occlusion of the proximal parent artery without obliteration of the aneurysm can result in early revascularization into the aneurysm via a newly-formed collateral network. Direct surgery can be an effective cure.