PVA（Polyvinyl alcohol foam）による髄膜腫塞栓術について

Preoperative Embolization for Meningiomas Using PVA Particles and Small Strips of Gelfoam

I．はじめに

　大きな，血管に富んだ，髄膜腫に対する術前塞栓術は，術中の出血量を減らし手術を容易に行ううえで，欠くことの出来ない摘出前手術手技である^21）．特に，外頸動脈枝より豊富な栄養血管の認められる，大きな頭蓋底部例で有効であり，術前血流を断っておかないと摘出が困難である．また，対側の外頸動脈枝からも栄養される，大脳鎌，傍矢状洞部例で有効と報告されている^22）．一方，塞栓術による重篤な合併症についても，相次いで報告がされてきている^{14,23,28,29,33）}．今回，頭蓋底部の巨大髄膜腫4例に対して，PVA及びジェルフォーム細片併用による術前塞栓術を行い良好な結果が得られたので，塞栓術の際の注意点，塞栓物質とその大きさ，合併症についても，検討を加えたので報告する．

Preoperative embolization for highly vascularized and large meningiomas is an indispensable technique for facilitating their surgical removal by decreasing blood loss during the operation. This is a report of 4 large and highly vascularizecl meningiomas in the skull base, on which embolization of feeders was performed preoperatively by PVA (Polyvinyl alcohol foam) parti-cles (150-250 micron produced by INGENOR CO, Paris) and small strips of gelfoam (0.5×0.5×3-5mm). Under EEG monitoring, Isosorbide dinitrate was used for prevention and relief of vascular spasm. Lidocaine injection tests (Xylocaine 2%: 50mg mixed in equal volumes with Iopamiron 300) were performed for checking before embolization. In the intracranial por-tion, standard taper steerable guide wire was changed to seeker flexible soft-tip guide wire. In two cases, the meningioma was located in the medial part of the sphe-noidal ridge. In the other two cases, one meningioma was in the lateral part of the sphenoidal ridge and the other was in the olfactory groove. In all 4 cases, we successfully performed embolization without complica-tion. In one case, we had to perform embolization twice, because of revascularization detected by angiography 3 weeks after the first embolization. In this latter case, we had performed central embolization only, by using PVA particles, having left feeder with-out occlusion (peripheral embolization) using gelfoam. The result suggested that it was also necessary to per-form peripheral embolization especially if the tumor is fed by large tortuous and irregular abnormal vessels. Peripheral embolization may prevent PVA particles from washing out and causing progressive thrombosis by PVA particles. Gelfoam is a suitable material for bringing about peripheral embolization, because it is an absorbable agent and is safe. Total or nearly total re-section of meningiomas could be performed with mini-mum loss of blood in all 4 cases. In three of the cases, intraoperative blood transfusion was not necessary.