[An experimental study of the treatment of aneurysms using an intravascular prosthesis]

Intracranial aneurysms occur frequently with the risk of major damage. Neurosurgery or endovascular techniques can be used for treatment. Current techniques are not well adapted for aneurysms with a wide implantation (or neck). The aim of this experimental work was to study a technique for treating aneurysms which can be used for wide neck aneurysms. A metal stent is implanted facing the neck of the aneurysm to allow occlusion. In the first part of the study, the stent was inserted alone. Ten aneurysms were created surgically in five dogs. The stents were positioned facing seven of the ten aneurysms. The stent led to immediate occlusion of the aneurysm in six of the cases. One aneurysm remained patent despite the correct position of the stent. One dog developed secondary thrombosis of the carotid. Three dogs have been followed for sixty days after insertion of the stent. Two aneurysms thrombosed and one was patent. Since these results were less than satisfactory, a second part of the study was undertaken to cover the stent with a fragment of the autologous vein. Results in five aneurysms, evaluated three and eight weeks after treatment, showed partial or total repermeabilization of the aneurysms. In the third part of the study, we associated stents and detachable coils. Twelve aneurysms of the carotid artery in pigs were thrombosed and two aneurysms were completely occluded after stent implantation. In the nine other cases, the aneurysms were completely occluded after stent implantation. In the nine other cases, the aneurysms remained patent despite the stent and treatment was then completed with a coil. Six of the animals have been followed for thirteen weeks. One carotid artery thrombosed. In the five other cases, the carotid arteries were patent and the aneurysms were occluded at the control angiogram. Histology results showed the presence of a fibromuscular endothelialized neointima at the neck of the aneurysm in four of the five cases. The technique described here could be proposed for the treatment of wide-neck aneurysms implanted low on the carotid artery in man. Improvements should render the system more flexible.