The expanding realm of endovascular neurosurgery: flow diversion for cerebral aneurysm management

Abstract

The worldwide prevalence of intracranial aneurysms is estimated to be between 5% and 10%, with some demographic variance. Subarachnoid hemorrhage secondary to ruptured intracranial aneurysm results in devastating neurological outcomes, leaving the majority of victims dead or disabled. Surgical clipping of intracranial aneurysms remained the definitive mode of treatment until Guglielmi detachable coils were introduced in the 1990s. This revolutionary innovation led to the recognition of neurointervention/neuroendovascular surgery as a bona fide option for intracranial aneurysms. Constant evolution of endovascular devices and techniques supported by several prospective randomized trials has catapulted the endovascular treatment of intracranial aneurysms to its current status as the preferred treatment modality for most ruptured and unruptured intracranial aneurysms. We are slowly transitioning from the era of coils to the era of flow diverters. Flow-diversion technology and techniques have revolutionized the treatment of wide-necked, giant, and fusiform aneurysms, where the results of microsurgery or conventional neuroendovascular strategies have traditionally been dismal. Although the Pipeline Embolization Device (ev3-Covidien, Irvine, CA) is the only flow-diversion device approved by the Food and Drug Administration for use in the United States, others are commercially available in Europe and South America, including the Silk (Balt Extrusion, Montmorency, France), Flow-Redirection Endoluminal Device (FRED; MicroVention, Tustin, CA), Surpass (Stryker, Kalamazoo, MI), and p64 (Phenox, Bochum, Germany). Improvements in technology and operator experience and the encouraging results of clinical trials have led to broader acceptance for the use of these devices in cerebral aneurysm management. Continued innovation and refinement of endovascular devices and techniques will inevitably improve technical success rates, reduce procedure-related complications, and broaden the endovascular therapeutic spectrum for varied aneurysm morphology.

Keywords: flow diverter; intracranial aneurysm; pipeline embolization device; subarachnoid hemorrhage.

A. H. Siddiqui, M.D., Ph.D.

Figure 1.

Images of Pipeline Embolization Device (ev3-Covidien, Irvine, CA) (A) being unsheathed inside a glass tube, and (B) deployed on the laboratory bench, under microangiographic fluoroscopic imaging. Image courtesy of Covidien Vascular Therapies. Pipeline is a trademark of a Covidien Company. © Covidien.

Figure 2.

A 37-year-old man experienced pain and weakness of the right arm for approximately 6 months, which he attributed to a pinched nerve. This progressively worsened over the last few weeks before his presentation to our institute; during this time, he also developed a noticeable facial droop and slurred speech and was dragging his right leg. (A) Cerebral angiogram, anteroposterior (AP) view, shows a 15-mm left posterior cerebral artery fusiform aneurysm, with (B) brainstem compression seen on magnetic resonance imaging. Access to the femoral artery was obtained bilaterally. A triaxial system with Neuron™ MAX (Penumbra, Inc., Alameda, CA), 5MAX™ (Penumbra, Inc.), and Marksman™ (ev3-Covidien, Irvine, CA) catheters was advanced into the left vertebral artery for deployment of a Pipeline™ Embolization Device (PED; ev3-Covidien). A 5-Fr Envoy^® Guiding Catheter (Codman & Shurtleff, Inc., Raynham, MA) with a PX SLIM™ Delivery Microcatheter (Penumbra, Inc.) was used to coil the aneurysm through the right vertebral artery. Angiograms of (C) anteroposterior and (D) lateral views show preliminary deployment of a single coil without detachment and deployment of the PED across the neck of the aneurysm. (E) Angiogram (AP view) at 3-months' follow-up shows complete obliteration of the aneurysm and a patent PED. The patient's symptoms resolved completely.