中硬膜動脈を栄養血管とする髄膜腫塞栓術において眼動脈との吻合のため工夫を要した1例

Embolization of the Feeding Artery of a Meningioma with Dangerous Vascular Anastomosis between the Middle Meningeal Artery and the Ophthalmic Artery

Ⅰ．はじめに

　髄膜腫開頭摘出術の前処置として行われる栄養血管塞栓術は，開頭摘出術中の出血量の軽減や手術時間の短縮，摘出中に確保困難な栄養血管の閉塞などを目的として行われることが多く，栄養血管が外頚動脈系であることが多いため脳血管内治療初心者の塞栓術トレーニングとしても行われやすい治療である．しかし，外頚動脈系血管の塞栓術では，いわゆるdangerous anastomosisや脳神経の栄養血管に注意を払わなければ思わぬ合併症を引き起こすことがあるのも事実である．

　今回われわれは，摘出術前に中硬膜動脈からの栄養血管塞栓術を施行した髄膜腫症例において，術中に中硬膜動脈と眼動脈との吻合を認めた症例を経験した．この血管吻合自体はよく知られているが，髄膜腫塞栓術に際しては常に注意が必要であると思われるため，若干の文献的考察を加えて報告する．

　Preoperative embolization of intracranial meningioma has been applied to reduce intraoperative blood loss and to facilitate microsurgical removal of a tumor. It is well known that one of the reasons of the neurological risk of embolization is due to dangerous anastomosis between the extracranial and the intracranial arteries. One of the most known and dangerous case of anastomosis is between the middle meningeal artery to the ophthalmic artery. A 48-year-old woman underwent preoperative embolization of a large right middle cranial fossa meningioma. The right external carotid angiogram showed that the tumor was fed by the right middle meningeal artery and there was no branch to the right orbital region. The right internal carotid angiogram showed that the right ophthalmic artery originated from the right internal carotid artery and there was no branch to the tumor. The selective angiogram of the anterior branch of the middle meningeal artery disclosed the anastomosis to the right ophthalmic artery. Following embolization of the anterior branch of the middle meningeal artery, the patient underwent embolization of the main feeding branch of the meningioma. She successfully underwent surgical removal of the tumor without any blood transfusion and was discharged without neurological deficit. In addition, to avoid complication in embolization of the feeding artery of a skull base meningioma, clinicians must be aware of the dangerous anastomosis between the middle meningeal artery and the ophthalmic artery, even if conventional external and internal carotid angiograms do not show any anastomosis.