Off-Label Uses for Flow Diversion in Intracranial Aneurysm Management

Treatment of complex aneurysms using microsurgical and other conventional neuroendovascular techniques remains challenging. As a result, stent- and balloon-assisted coiling are instead performed to treat morphologically complex aneurysms, which include giant, wide-necked, and fusiform aneurysms. While these techniques have had success in treating these complex aneurysms, recanalization rates associated with these techniques are still problematic. In the constant effort to improve the outcome of complex aneurysm treatment, flow-diverting stents (FDSs) have emerged in recent years as the preferred treatment. Instead of directly obstructing the flow of blood into the aneurysmal sac, as is the case for stent- and balloon-assisted coiling, FDSs are placed in the parent blood vessel to divert blood flow away from the aneurysm itself. Subsequent to the diverting away of blood from the aneurysm, a thrombotic cascade ensues that ultimately results in the closure of the aneurysm while the parent vessel's perforators are preserved. Current known risks for this procedure include vessel rupture or perforation, in-stent thrombosis, perforator occlusion, procedural or delayed hemorrhages, and perianeurysmal edema. In this review, we will evaluate the mechanisms of actions, clinical applications, complications, and ongoing studies for FDSs.