Endovascular embolization of aneurysms with ALGEL®: an in vitro study of delivery techniques and resulting gel stability

Continued studies with calcium alginate gel (ALGEL®-Neural Intervention Technologies, Ann Arbor, MI) show promise as an aneurysm occlusion material. Controlled ALGEL delivery eliminates flow to aneurysms and, when combined with coils, can eliminate the potential for ALGEL outflow from wide-neck, high flow aneurysms. Several aneurysm sizes were cast in flexible resins to simulate side-wall and bifurcation aneurysms in an in vitro system. First, ALGEL was delivered to small neck aneurysms from a 3F dual-lumen microcatheter. Second, a minimal number of coils were delivered to wide-neck aneurysms to form a matrix structure. ALGEL was then delivered to fill the remaining aneurysm space. ALGEL completely and effectively filled both small-neck aneurysms and, when combined with coils, completely filled wide-neck, high-flow aneurysms and eliminated outflow. Mechanical testing of ALGEL compared shear resistance to estimated shears seen in vivo. The frequency dependence of the complex modulus was determined at multiple % shears. ALGEL exhibits adequate stability to resist typical in vivo blood flow and shear effects subjected on aneurysms. ALGEL´s mechanical stability and effective occlusion, alone and in combination with coils, makes ALGEL a potentially novel candidate for treating a wide variety of aneurysms and other neurovascular lesions.