脳動脈瘤手術後に網脈絡膜循環不全を伴った眼窩先端症候群を生じた2症例

Two cases of orbital apex syndrome with marked chorio-retinal ischemia following surgery for intracranial aneurysm

　脳動脈瘤手術後に著明な網脈絡膜循環不全を伴った眼窩先端症候群を呈し，失明に至った2症例を経験した。1例では，術後の脳血管造影にて海綿静脈洞血栓症の合併が確認された。いずれの症例も，手術中に眼窩外部からうけた圧迫による眼窩内圧の上昇が発症の原因と推察した。長時間の圧迫による眼窩内虚血が，眼窩内軟部組織の腫脹を招き，また眼窩内の血流うっ滞は2次的に海綿静脈洞血栓症等の眼窩draining veinの血栓形成をきたしうると思われる。その結果眼窩内圧はさらに上昇し眼窩先端部を通過する神経，動静脈群を絞扼し眼窩先端症候群と著明な網脈絡膜循環不全を呈したものと考えた。脳外科手術時の眼球保護の重要性を強調したい。

We observed two cases of unilateral blindness following clipping of intracranial aneurysm. Both cases manifested orbital apex syndrome with marked retinochoroidal ischemia. Cerebral angiography later showed cavernous sinus thrombosis in one case. Prolonged compression to the orbit during surgery with resultant swelling of intraorbital tissue and orbital ischemia appeared to be the causative factor in these cases. The observed cavenous sinus thrombosis seems to have been the result of impaired circulation in the orbit with thrombosis of orbital veins. These features would have led to further elevation of intraorbital pressure, orbital apex syndrome and retinochoroidal ischemia. We emphasize the importance of avoiding inadvertent compression of the orbit during surgery for intracranial aneurysms.