An endovascular approach to ruptured aneurysms of the circumferential branch of the basilar artery

Aneurysms of the basilar perforating arteries are uncommon and those of the circumferential artery are particularly rare. Microsurgical clipping or trapping is the preferred treatment as these aneurysms are usually not accessible for endovascular treatment. We report two patients with ruptured aneurysms arising from the basilar circumferential artery. The first patient, a 66-year-old male, presented with a prepontine hematoma and a delayed filling aneurysm of the basilar circumferential artery. The second patient, a 28-year-old female, presented with a narrow-neck aneurysm of the basilar circumferential artery, associated with an arteriovenous malformation in the left cerebellum. Both patients were treated successfully with endovascular coiling, flow was preserved in the perforating parent vessels and the patients had excellent outcomes. This is the first report of this type of aneurysm being successfully treated by endovascular coiling. The treatment challenges regarding microsurgical and endovascular approaches are discussed.