椎骨動脈・後下小脳動脈分岐部動脈瘤の外科

Surgery of Vertebral Aneurysms at the Origin of PICA

Ⅰ．緒言

　椎骨動脈・後下小脳動脈分岐部動脈瘤（以後VA・PICA動脈瘤と略す）は後頭蓋窩動脈瘤の内で，脳底動脈分岐部動脈瘤，脳底動脈幹動脈瘤と同様に多く見られる．しかし，その診断に際しては，後頭蓋窩底骨陰影と血管像が重なるため読影困難で，原因不明のくも膜下出血として放置されている場合もある．

　我々は椎骨動脈動脈瘤が疑われる場合，または原因不明のくも膜下出血の場合の椎骨動脈撮影に際し，必ず開口位撮影を行い，椎骨動脈・後下小脳動脈分岐部の動脈瘤の有無を観察している．

Thirteen cases of vertebral aneurysm at the origin of PICA (VA-PICA aneurysm) were operated on at the Department of Neurological Surgery of Kitano Hospital from March, 1970 through July, 1975. Those included 9 cases of saccular aneurysm and 5 cases of fusiform aneurysm (Table 1). The incidence of VA-PICA aneu-rysms among our whole series of intracranial aneurysms was 4.2%.

Patients with subarachnoid hemorrhage were subjected to our routine 4 vessel angiography. For those with suspected vertebral aneurysm vertebral angiography was performed in a transoral projection.