Web embolization is a minimally invasive procedure used to treat certain types of brain aneurysms. This endovascular approach involves navigating specialized tools through blood vessels to reach the affected area within the brain. The primary goal is to seal off the aneurysm, preventing it from rupturing and causing a potentially dangerous bleeding stroke. It offers a less invasive alternative to open brain surgery.
Aneurysms Treated with the WEB Device
A brain aneurysm is a weakened, bulging section of a blood vessel wall. The Woven EndoBridge (WEB) device is specifically designed for complex cases known as wide-neck bifurcation aneurysms. A “bifurcation” refers to a point where a blood vessel divides into two or more branches, such as those found in the middle cerebral artery or basilar artery apex. A “wide-neck” aneurysm means the opening where the aneurysm connects to the main blood vessel is broad, typically defined as having a neck width of 4 millimeters or greater, or a dome-to-neck ratio less than 2.
The wide opening of these aneurysms makes traditional treatments like coil embolization challenging because the coils placed inside might protrude back into the main blood vessel. Furthermore, bifurcation aneurysms present an additional hurdle: the need to preserve the branching blood vessels that originate from or near the aneurysm’s neck. These anatomical complexities make wide-neck bifurcation aneurysms particularly difficult to treat with standard endovascular coiling alone.
The Web Embolization Procedure
The web embolization procedure begins with diagnostic imaging, such as an angiogram, to map the brain’s blood vessels and the aneurysm’s precise location. Patients typically receive general anesthesia for comfort and stillness. A small incision is then made, most commonly in the femoral artery in the groin.
Through this incision, a slender, flexible tube called a catheter is inserted into the artery and guided through the vascular network to the aneurysm site in the brain. Once positioned, the WEB device, which is a self-expanding mesh implant made of nitinol, is carefully deployed from the catheter directly into the aneurysm sac. The device then expands to conform to the aneurysm’s internal shape and walls.
This mesh structure disrupts blood flow entering the aneurysm. The reduced blood flow within the aneurysm sac promotes the formation of blood clots, a process known as thrombosis, which effectively seals off the aneurysm from the main circulation.
Recovery and Follow-Up Care
Following a web embolization procedure, patients typically recover in the hospital, often with initial monitoring in an intensive care unit, to observe for complications and manage initial recovery. Once stable, patients usually return home, where short-term recovery may involve fatigue or soreness at the catheter insertion site.
Long-term success relies on diligent follow-up care to ensure the aneurysm remains securely occluded. Regular follow-up imaging studies, such as digital subtraction angiography (DSA) or computed tomography angiography (CTA), are standard. Magnetic resonance angiography (MRA) may not be suitable for follow-up imaging due to potential image degradation caused by the WEB device. Follow-up appointments are scheduled over months and years to monitor the treated aneurysm’s stability and confirm long-term effectiveness.