Basilar Artery Fenestration Aneurysms: Endovascular Treatment Strategies Based on 3D Morphology

Basilar artery is the second most common site of fenestration, after the anterior communicating region. It is believed this variation predisposes a patient to posterior aneurysm formation and increases the complexity of the surgical anatomy. Endovascular management has become the first option to treat these aneurysms. We retrospectively evaluated eight patients, who underwent endovascular treatment for fenestrated basilar artery related aneurysms (fBA-AN). Additionally, based on our findings and on literature review, we developed a treatment strategy based on a proposed classification of fBA-AN. Between June 2010 and September 2012, eight patients harboring nine basilar artery fenestration aneurysms were consecutively treated. Based on aneurysm morphology (neck size) and its relationship to the fenestration (sparing or not one channel) characterized by 3D-DSA, we proposed a simple classification and treatment strategies. Additionally, a literature review was performed. All patients received endovascular treatment. Most aneurysms involved the vertebrobasilar junction and both channels of the fenestration. A total of 5 aneurysms had wide neck while 4 had narrow neck. Overall, 5 (55.5 %) aneurysms were treated with stent assisted coiling, 3 (33.3 %) aneurysms with selective coiling, and 1 (11.1 %) aneurysm with balloon assisted coiling. We had only 1 (11.1 %) complication, named aneurysm rupture. Basilar artery fenestration aneurysms are rare and complex lesions. Endovascular treatment appears to be safe and efficient. The detailed understanding of the aneurysm morphology and its relation to the fenestration is strongly recommended to treatment planning. Further studies are necessary to validate the utility of the proposed classification and treatment strategy.