脳出血にて発症した頭蓋内pial arteriovenous fistulasの1例

Intracranial Pial Arteriovenous Fistulas

Ⅰ．はじめに

　Pial arteriovenous fistulas（pial AVF）は脳動脈と脳静脈がnidusを介することなく直接交通するものであり，脳動静脈奇形（arteriovenous malformation：AVM）や硬膜動静脈瘻（dural AVF）とは異なる病態である^3,5)．発症頻度は頭蓋内動静脈短絡疾患のうち1.6～4.8％^2,7,12,13)とされ，稀な疾患である．頭蓋内出血で発症する場合も多いが，出血発症例の場合は保存的治療では予後不良であるため⁹⁾，早期に血管内治療や開頭手術などの根治的治療が必要となる．今回われわれは，脳出血で発症したpial AVFに対して直達手術を行い，良好な予後を得ることができた．当症例について文献的考察を含めて報告する．

　A 25-year-old man presented with right hemiparesis and was admitted to the local hospital. CT scan revealed an intracerebral hematoma in the left motor cortex. He was treated conservatively,the hematoma passed without increase and his right hemiparesis improved gradually. The cause of hemorrhage was examined at the local hospital without resolution. He came to our hospital for further examination. Angiography revealed pial arteriovenous fistulas near the hematoma. The fistulas were fed by small branches of the left anterior cerebral artery and drained into an abnormal cortical vein. Left parietal craniotomy was performed. A red dilated cortical vein existed under the thickened,cloudy arachnoid membrane. Retrograde observation of the red vein showed some small branches connected directly to the red vein at the central sulcus. There was no nidus. The color of the red vein changed to blue after disconnection of the fistulas by electrocoagulation. The dilated cortical vein was resected. Postoperative angiography revealed the disappearance of the fistulas. He was discharged without any new neurological deficits. Intracranial pial arteriovenous fistulas are rare cerebrovascular lesions. As symptomatic patients managed conservatively have a poor prognosis,radical treatment should be undertaken as soon as possible.