確実な脳動静脈奇形全摘のための手術戦略 : 脳動静脈奇形の治療  [in Japanese] Treatment Strategies and Pitfalls of AVM Surgery  [in Japanese]

自然経過 脳動静脈奇形(以後AVMと略す)は血管奇形の中でも最も発生頻度が高く, 剖検例では4%に認める. AVMの治療の大きな目的の1つは言うまでもなく出血予防である. 1997年の報告では出血発症と非出血発症の年間出血率はそれぞれ17.8%, 2.2%であり, 野崎らも, 出血発症例の再出血率は年間16.6%で, いったん出血を起こした脳動静脈奇形の出血率が予想以上に高いことを報告している. また1回の出血でのmortalityは10%, morbidityは30%といわれる. これに向けた治療成績は自然歴を上回ることが課せられる. 近年, 治療戦略としてはadjuvant therapyのγナイフ, 血管内外科治療の治療進歩に伴い, 直達手術が減ったかの感がある. しかし, γナイフのmortalityは1-6%ともいわれており, 完全に摘出できる直達手術の見直しが必要な時期を迎えている. 本項では, AVMに対する当教室での治療適応の考え方に合わせて外科的摘出術のポイント, および術中の出血コントロールを中心に述べる.

There is high risk of intraoperative hemorrhage in AVM surgery due to abnormal vessels and changing hemodynamic pattern of brain. Inadequate coagulation of vessels, arterialization of veins and loss of tissue planes are major pitfalls. Preoperative embolization and temporary clipping of feeding arteries contribute to safe surgical techniques. There were 281 patients who underwent treatment for AVM: in our institution: 242 were operated (99 of them with intracerebral hemorrhage) and 39 cases were treated with embolization and/or gamma knife. Radiological evaluation was carried out, by CT, dynamic and 3D-CT. MRI, fMRI, MRA, and surface anatomy scanning. Strategic image analysis and preoperative embolization were employed where feeders were behind the nidus or vein and where another craniotomV. was found necessary to secure feeding arteries. Endovascular nidus obliteration is successful only in 10% of patients. Surgical results showed risk of intraoperative bleeding in Grade 4 and 5 cases (1.5%). Recovery showed GR (205). MD (13). SD (7). PVS (2), and death (15) on 242 cases, based on Glasgow Outcome Score. Preoperative staged nidus embolization helps prevent bleeding in large AVM; small superficial lesions have the best results with surgery. Temporary clips for feeders, good plane between nidus and brain, definition of eloquent cortex, adequate coagulation of draining veins and total nidus excision are important, steps in surgical strategy.