The authors evaluated the embolization effects on experimental aneurysm models with a liquid material. This material is a mixture of poly (HEMA-co-MMA), Iopamidol, water and a small amount of ethyl alcohol. We have satisfactorily treated over 30 cases of AVM with this material. Out of four solutions of different viscosity, we used the solution with the highest viscosity to prevent distal migration of the mixture. Glass models of aneurysms of 5 mm in diameter in pulsatile saline flow were embolized with the mixture under various conditions. When an IDC was placed in the aneurysm models, the mixture obliterated them completely and did not migrate out from the aneurysm models. In this experimental study, it is suggested that the liquid material appears to be useful in embolizing cerebral aneurysms safely.

We evaluated the usefulness of endovascular treatment of posterior circulation aneurysms with GDCs and IDCs, Five cases were treated with IDCs, and 15 cases were treated with GDCs. In this study, 8 aneurysms were identified at the basilar bifurcation, 3 at the P1 segment of the pasterior cerebral artery, 1 at the origin of the superior cerebellar artery, 2 at the vertebrobasilar junction, 1 at the origin of the posterior inferior cerebellar artery, 1 at the distal anterior inferior cerebellar artery, and 4 dissecting aneurysms at the vertebral artery. Thirteen of the aneurysms were small (< 12 mm), 5 were large (13–24 mm), and 2 were giant (> 25 mm). Of the 20 patients, 14 patients returned to their previous occupation. Patients with permanent deficits included 2 patients with infarction caused by thromboembolic complications during the embolization procedure, and 2 with infarction caused by vasospasm. There were 2 deaths. The outcomes of the patients seemed favorable. However, long-term follow-up is necessary to determine the usefulness of detachable coils.

Characteristics of a newly developed liquid material for embolization of AVM and its clinical experiments are reported. This liquid is composed of dissolving poly (2-hydroxyethyl methacrylate-co-methyl methacrylate) in Iopamiron with adding a small amount of ethyl alcohol. Thirty-two cases of AVM and 5 cases of spinal AVM were embolized with this liquid with good results. This liquid material is of low viscosity, not adhesive and not cytotoxic, therefore, it can be easily injected through a microcatheter, and can safely and effectively occlude AVM.

We reported the scanning electron microscopic findings of an aneurysm embolized with interlocking detachable coils (IDC). A 78-year-old man was referred to our hospital because of left hemiparesis and dysphagia. CT scan showed multiple lacunar infarction in the bilateral corona radiata. Angiography demonstrated a small incidental aneurysm of the right internal carotid artery (IC-PC junction). The left hemiparesis gradually improved and 2 weeks after admission the aneurysm was treated with IDC. Three coils were placed in the aneurysm and post-operative angiography demonstrated complete embolization. Dysphagia caused by the pseudobulbar pulse did not improve and, 4 weeks after endovascular surgery, the patient died of aspiration pneumonia. An autopsy was performed and the scanning electron microscopical findings of the aneurysm showed development of endothelial cells on the coil surface. Many clinical reports supported the usefulness of Guglielmi detachable coils (GDC) and several experimental reports demonstrated the intimal proliferation in aneurysms embolized with coils. However, pathological changes of the aneurysms treated with coils have been reported in only four clinical cases. There was no evidence of endothelialization in any of these cases. To our knowledge, our case is the first report describing the endothelial proliferation over the coils. It is necessary to accumulate histopathological data and long-term follow-up in humans treated with coils.