前方循環未破裂脳動脈瘤に対する低侵襲化直達手術—lateral supraorbital approachの有用性と注意点

Advantages and Pitfalls of the Lateral Supraorbital Approach as Less Invasive Surgery for Unruptured Anterior Circulation Aneurysms

Ⅰ．緒　　言

　近年，血管内治療の進歩により，未破裂脳動脈瘤に対する直達手術の役割はより限定的になってきている．血管内治療に対する直達手術の主な長所として，柔軟性（wide neck瘤やdomeから血管が分岐している瘤に対し，血管形成的なclippingやbypass併用が可能なこと），安全性（直視下で行えるため，術中破裂など万が一の合併症にも対処しやすいこと），根治性（再発率が低いこと）が挙げられるが，侵襲性に関しては間違いなく血管内治療に劣る．

　Lateral supraorbital approach（LSOA）は開頭野にsylvian fissureおよび最小限の前頭葉しか露出せず，従来のpterional approach（PA）に比べ，小さな皮膚切開と開頭範囲で直達手術が可能な方法である（Fig.1)²⁾．われわれは前方循環未破裂脳動脈瘤に対し，直達手術の長所を損ねずに低侵襲化することを目指し，LSOAで直達手術を行っている．この治療成績を報告し，従来のPAと比較した利点と注意点を考察する．

　The lateral supraorbital approach（LSOA）is widely accepted as a less invasive surgical technique compared with the conventional pterional approach（PA). However, only a few studies have reported less invasiveness associated with LSOA. To evaluate this issue, we retrospectively investigated the surgical outcomes in 133 patients who underwent LSOA and 28 patients who underwent PA for unruptured anterior circulation aneurysms. We analyzed operation time, postoperative symptoms and complications, and the length of postoperative hospitalization（in days）for each method.

　All aneurysms were successfully clipped regardless of the approach. The operation time was significantly shorter, the postoperative headache rate was lower, resumption of oral intake was more rapid, and length of hospitalization was shorter in the LSOA group. Statistical significance was not observed in the postoperative complication rates.

　Compared with conventional PA, LSOA was associated with less invasiveness and better patient satisfaction. LSOA is a safe and effective alternative to conventional PA, following optimal patient selection.