Surgical Construction of Wide-Neck Bifurcation Experimental Aneurysm in an In Vivo Canine Model to Test Neurovascular Device

Stents are increasingly used for coiling difficult aneurysms, to reduce the risk of recurrences, or to modify blood flow. Currently, available bifurcation aneurysm models are ill-suited to assess stent performance before clinical use. We designed a new animal model of wide-neck canine Y-type bifurcation aneurysm (such as middle cerebral artery (MCA) bifurcation) and previously reported one of T-type (such as basilar bifurcation). Its potential value as a training tool as well as in the evaluation of new techniques or stent or embolic agents was assessed. Seven canine aneurysms were created (three: Y-type, four: T-type). Aneurysms were followed by transfemoral cerebral angiography (TFCA) and computed tomography angiography (CTA). We performed TFCA and self-expandable stent placement for the parent artery adjoined to the aneurysmal neck in one month's follow-up. We assessed the long-term patency of the parent artery with CTA and euthanasia and got a specimen for pathologic study at six months' follow-up. In six models except one (T-type), a wide-neck bifurcation aneurysm was created successfully and they showed good long-term patency at six months' follow-up. Stent placement was technically difficult in these cases, but did not lead to aneurysm thrombosis in CTA or neointimal closure of the aneurysm neck in pathologic finding at postoperative six months later. This model may be suitable for studying the effects of endovascular treatment on aneurysm and branch occlusion rates, for preclinical testing of stents and other intravascular devices, and for training students in endovascular technique.