Flow Diversion of an Incompletely-Treated Fusiform Middle Cerebral Artery Aneurysm: 2-Dimensional Operative Video.

Fusiform aneurysms involving the M2 branches of the middle cerebral artery are often dissecting, identified by a characteristic diseased adjacent segment, and location not at a branch point. Herein, we present the case of a 38-yr-old man with a symptomatic, dissecting M2 aneurysm that was previously incompletely treated with stent-assisted coiling. In our experience, symptomatic fusiform aneurysms in this location tend to recur unless the involved segment is completely trapped or reconstructed with flow diversion. We successfully treated this patient with a vessel reconstruction using a Pipeline Flex Embolization Device (Medtronic). Deployment of a flow diverter inside a previously placed stent can pose potential challenges, as the original stent may constrain complete expansion of the flow diverter and prevent perfect apposition against the parent vessel wall. In this operative video, we demonstrate this technique and provide a brief discussion of the potential pitfalls.