Evaluation of a novel polymer coil for endovascular occlusion of intracranial aneurysms in a rabbit model

Background and Purpose: The results of the preclinical study of a novel polymer coil in treatment of elastase induced aneurysms will be presented in this paper. Material and Methods: We induced 16 aneurysms in 16 New Zealand white rabbits at the origin of the right common carotid artery at the brachiocephalic trunk. Newly developed polymer coils in both groups for six aneurysms each and platinum coils for two aneurysms each were used. Control angiographies followed in both groups immediately after coiling as well as in the first eight animals 30 days after intervention (30 days group) and in the other eight animals 90 days after (90 days group). An explanation and histological evaluation of the treated aneurysms followed. Results: The 12 animals in which the aneurysms were treated with polymer coils showed a complete occlusion (grade IV) in only 6 out of 12 aneurysms (50%), an almost complete occlusion (grade III) in 5 out of 12 (42%) and an incomplete occlusion in the treatment of one aneurysm (8%). Histologically, we observed a significantly more pronounced inflammatory response and neoangiogenesis in aneurysms treated with polymer coils only in the 30 days group. Conclusion: Most difficulties and concerns with the polymer coils were related to the flexibility and detachment behaviour. Therefore, and due to the technical challenges of delivery, the novel polymer coil cannot be considered an alternative to the current platinum coils.