Aneurysm of the Fenestrated Basilar Artery: Case Report and Literature Review

Introduction: Aneurysms of the vertebrobasilar junction are rare, but when present, they are often associated with fenestration of the basilar artery. Frequently, the endovascular treatment is the first choice due to the complex anatomy of the posterior fossa, which represents a challenge for the open surgical treatment alternative. Case Report: A 47-year-old man was admitted to the emergency unit with headache, diplopia, neck pain and mental confusion. The neurological exam showed: score of 15 in the Glasgow coma scale (GCS), no motor or sensitivity deficit, palsy of the left sixth cranial nerve and Hunt-Hess grade III. The computed tomography (CT) scan showed subarachnoid hemorrhage (Fisher III) and hydrocephalus. The patient was submitted to ventricular-peritoneal shunt. A diagnostic angiography was performed with 3D reconstruction, which showed evidence of fenestration of the basilar artery associated with aneurysm in the right vertebrobasilar portion. An aneurysm coil embolization was performed without complications. The patient was discharged 19 days later maintaining diplopia, with paralysis of the left sixth cranial nerve, but without any other complaints or neurological symptoms. Discussion: Fenestration of the basilar artery occurs due to failure of fusion of the longitudinal neural arteries in the embryonic period, and it is associated with the formation of aneurysms. The endovascular treatment is the first choice and several techniques are described, including simple coiling, balloon remodeling, stent-assisted coiling, liquid embolic agents and flow diversion devices. The three-dimensional rotational angiography (3DRA) is an extremely helpful tool when planning the best treatment course. Conclusion: Fenestrated basilar artery aneurysms are rare and complex vascular diseases and their treatment improved with the advent of the 3D angiography and the development of the endovascular techniques.