Application of the Willis covered stent using the telescopic technique for the treatment of fusiform aneurysm in a canine model

BACKGROUND: The covered stent is one of the most promising tools for the treatment of intracranial fusiform aneurysms. We developed an in vivo model of fusiform aneurysms and evaluated the effectiveness of double telescoping Willis covered stents for their treatment. MATERIALS AND METHODS: An external jugular vein graft was anastomosed with the common carotid artery (CCA) to construct the fusiform aneurysm model. After at least 4 weeks, two Willis covered stents were implanted in a telescopic fashion. Angiography follow-up was performed at 2 weeks and 1 and 3 months to examine the grafts. The animals were sacrificed at 1 or 3 months of the follow-up period, and the stents were examined histologically. RESULTS: A total of eight fusiform aneurysms in four canines were created and 16 covered stents were implanted successfully. No technical or device-related difficulties occurred. The angiographic follow-up results showed that six fusiform aneurysms were completely occluded, and a minimal endoleak occurred in two fusiform aneurysms. Histological examination revealed endothelial progress and all aneurysm sacs were filled with thrombi. CONCLUSION: Vein graft anastomosis with CCA to construct a model of fusiform aneurysm may reproduce the clinical conditions. This study demonstrated that the implantation of two Willis covered stents in a telescoping fashion is an effective way to treat an experimental model of fusiform aneurysm.