Paraclinoid aneurysmの治療戦略  [in Japanese] Therapeutic Strategies for Paraclinoid Aneurysms  [in Japanese]

内頸動脈において海綿静脈洞から遠位部で後交通動脈分岐部までの部分にできた動脈瘤はparaclinoid aneurysm(傍前床突起部動脈瘤)と総称され,上下垂体動脈分岐部動脈瘤,眼動脈分岐部動脈瘤,carotid cave aneurysm(内頸動脈窩動脈瘤),分岐に関係しない動脈瘤などが含まれる.同部位の動脈瘤に対する直達手術を安全かつ確実に行うためには,頸部頸動脈確保,前床突起削除,視神経管開放と視神経鞘切開,硬膜輪切開などの手技に習熟することが必要となる.特に大きな動脈瘤で視神経を強く圧迫している場合や動脈瘤頸部が海綿静脈洞内へ伸展している場合にはドリリングやクリッピングの際に注意を要する.一方,近年の血管内治療の発達,普及により同部位の動脈瘤に対する塞栓術の適応が拡大しつつある.脳動脈瘤塞栓術については,破裂動脈瘤に対する急性期の再出血予防効果は認められているものの,未破裂脳動脈瘤に対する長期成績は不明であり,直達手術が困難であるという理由のみで安易に行われるべきではないと思われる.本稿では,当科で経験したparaclinoid aneurysmの治療成績を検討し,同部位の脳動脈瘤に対する至適治療選択について考察した.

To establish the optimal therapeutic strategy for paraclinoid aneurysms, we retrospectively analyzed our clinical experiences in 51 patients with .54 paraclinoid aneurysms who had been admitted to our institute since April 1994. The aneurysms were classified as la (7), Ib (7), II (17). III (21) and IV (2), according to Al-Rodhan et a,1., and the sizes of aneurysms (mm) were 3-5 in 27, 6-10 in 15, 11-15 in 3, 16-20 in 6 and > 21 in 3 cases. Eight cases showed progressive aggravation of visual symptoms, and 3 cases suffered from SAH. Thin-slice CT provided useful anatomical information of the skull base bony structure and subarachnoid space. Open surgery (OS) (clipping 23, coating 2) resulted in complete anatomical cure in 22 cases (88%), and endovascular surgery (ES) (endosaccular occlusion, 23; IC occlusion, 3) resulted in complete anatomical cure in 18 cases (69%). Aneurysms in Groups la and 11 obtained relatively lower anatomical cure in ES when compared with other groups and OS. Treatment-related complications occurred in 2 large cases (aggravation of visual acuity, basal ggl infarction) of OS and in 3 cases (2 premature rupture, I borderzone infarction) of ES. OS is recommended for Groups I and II considering anatomical curability. In Group III, OS is recommended for large symptomatic cases and ES for small ruptured cases to prevent symptomatic aggravation. Small asymptomatic cases in Group III should be treated considering treatment-related risks. Observation is recommended in cases of Group IV if they are asymptomatic.