経静脈的塞栓術の併用で根治した，脊柱管内巨大静脈瘤を伴った頸椎傍脊椎部動静脈瘻の1例

A Case of Cervical Paraspinal Arteriovenous Fistulae with a Huge Intracanalicular Varix Successfully Treated with Transvenous Embolization

Ⅰ．は じ め に

　脊髄動静脈奇形（spinal arteriovenous malformation：spinal AVM）のうち，椎体周囲の静脈との間にarteriovenous shunt（AVS）を形成する，比較的稀なタイプの病変の存在が知られており，傍脊髄／脊椎部動静脈短絡：paraspinal/paravertebral AVSなどと称されている．Paraspinal/paravertebral AVSの症状発現の機序としては，perimedullary veinへの逆流によりcongestive myelopathyを呈するものと，拡張した静脈構造によりcompressive myelopathyを呈するもののいずれもあり得る^9,24)．今回，われわれは，多数の血管群がfeederとなり，脊柱管内のvarixにてcompressive myelopathyを呈した傍脊椎部動静脈瘻に対して経静脈的塞栓術を行い，良好な治療効果をあげることが可能であった症例を経験したので，治療戦略を中心に考察し報告する．

　Paraspinal arteriovenous fistulas (AVFs), with the fistulas draining into the epidural veins alone, are relatively rare and few cases have been reported until now. We reported a case of cervical paraspinal AVFs draining only into the epidural venous plexus without reflux into the intradural venous system. The patient showed myelopathy due to direct compression of the spinal cord by a large varix.

　A 57-year-old man presented with gait disturbance. Neurological findings on admission revealed that tetraparesis, sensory disturbance of four extremitas below the C5 level and bladder bowel dysfunction. Magnetic resonance imaging and computed tomography at the cervical level disclosed remarkable compression of the spinal cord by a large venous pouch at the C6 level. Digital subtraction angiography (DSA) revealed paraspinal arteriovenous fistulas fed by bilateral C6 radicular arteries, the right ascending cervical arteries, and the right deep cervical artery in the right C6 intervertebral foramen. Three-staged transarterial embolization was performed by selective catheterization of the multiple feeders with n-butylcyanoacrylate, followed by transvenous embolization. During transvenous embolization, motor evoked potential (MEP) monitoring was performed. After retrograde catheterization of the epidural venous plexus, the large varix was occluded with Guglielmi detachable coils. The AV fistulas were completely occluded without any change in MEP monitoring during the procedure. The patient's gait improved well after the procedure and follow up DSA six months later showed no recurrence of the paraspinal AVFs.