慢性中耳炎が原因と考えられた錐体部内頸動脈瘤の1例

Endovascular Treatment of Large Petrous Internal Carotid Artery Aneurysm Associated with Chronic Otitis Media : Case Report

Ⅰ．は じ め に

　脳動脈瘤の発生にはさまざまな要因が関与し，また頭蓋内脳動脈瘤に対する手術方法は頭蓋底外科や血管内治療により治療成績は向上してきた．しかし，内頸動脈錐体部に生じる動脈瘤は比較的稀で，錐体骨内に発生するため外科的治療が困難である．またその成因にも，頭蓋内脳動脈瘤とは特徴が異なる点が多い．今回，われわれは慢性中耳炎の関与が示唆された錐体部内頸動脈瘤に対しコイル塞栓術を施行し，良好な結果を得たので報告する．

Aneurysms of the petrous internal carotid artery are rare,and surgical treatment of the aneurysm in the petrous bone carries high risk with procedure. We report a case of large petrous internal carotid artery aneurysm associated with otitis media. A 58-year-old female was admitted to our institution with left hearing loss and facial palsy. She had 4-year history of left exudative otitis media. Imaging studies demonstrated a 17 mm left petrous internal carotid artery aneurysm,destroying osseous partition between carotid canal and Eustachian tube,and protruding into left middle cranial fossa. Endosaccular coil embolization with balloon assist technique was performed successfully without neurological deficit. Follow up magnetic resonance angiogram demonstrated complete obliteration of the aneurysm without parent artery occlusion.

　Traumatic,mycotic,radiation,and congenital origin have been implicated for petrous internal carotid artery aneurysm. In a review of the literature,11 cases of mycotic aneurysms in this location were reported and all of them were complicated with chronic otitis media. Because of its close proximity of middle ear and Eustachian tube,adventitial infection of the artery weakens the arterial wall,and gives rise to formation of aneurysm. We conclude that our case is of mycotic origin,and endosaccular coil embolization is effective and less invasive treatment.