flowdiversion

Flow diversion is a vascular neurosurgical strategy that uses flow-diverting devices to treat certain intracranial aneurysms by redirecting blood flow away from the aneurysm sac, promoting thrombosis and remodeling of the vessel. It is typically used for complex aneurysms that are difficult to treat with coils or clipping.

Mechanism: Flow-diverting stents provide high metal coverage across the aneurysm neck, reducing inflow into the sac and lowering wall shear stress. Over weeks to months the stent surface promotes endothelialization and exclusion of the aneurysm while preserving patency of the parent artery.

Indications: Large, wide-neck, fusiform, or distal intracranial aneurysms; aneurysms not amenable to coiling. Contraindications include small-vessel caliber, tortuosity, lack of collateral flow, or situations where antiplatelet therapy cannot be safely administered, such as certain ruptured aneurysms or preoperative bleeding risk.

Procedure and management: Performed endovascularly with catheter-based delivery of a flow-diverting stent. Patients typically receive dual antiplatelet therapy before and after treatment. Postprocedural imaging is used to monitor aneurysm occlusion and vessel remodeling.

Outcomes and risks: Occlusion rates improve over months; many large or complex aneurysms achieve complete occlusion with time. Potential complications include thromboembolism, in-stent stenosis, perforator infarcts, and delayed aneurysm rupture; some aneurysms require adjunctive procedures or alternative therapies.

History: The concept emerged in the late 2000s with devices such as the Pipeline Embolization Device, followed by others; widespread use expanded in the 2010s as evidence accumulated. Ongoing research continues to define optimal indications and long-term durability.