Stent-Assisted Coiling of Aneurysm in a Persistent Primitive Lateral Vertebrobasilar System.

Fenestrations of cerebral arteries are relatively common. Knowledge of their structure has recently gained clinical significance with increasing awareness of fenestration aneurysms. Persistent primitive lateral vertebrobasilar (PPLVB) anastomoses are an extreme end of the embryologic mishaps causing these fenestrations, and their occurrence has only been reported twice. We report the first case of an aneurysm within the PPLVB in a patient with unilateral subclavian stenosis. The unique anatomy of these aneurysms and relation with important perforators and brainstem make surgery extremely difficult and require advanced endovascular techniques like balloon remodeling and stent assistance. Three-dimensional rotational angiography can help in providing clarity to the aneurysmal anatomy and planning treatment. The purpose of this case report is to bring to notice the possibility of such aneurysms and use the unique anatomy to understand various tools available in the endovascular surgeon's armamentarium.