脊髄円錐部および馬尾に複数のAV shuntを形成した脊髄辺縁部動静脈瘻の1例

Conus Perimedullary Arteriovenous Fistula with Multiple Shunt Points Including the Cauda Equina: A Case Report

Ⅰ．はじめに

　脊髄動静脈奇形（spinal AVM）は，AV shuntの解剖学的部位よりintramedullary AVM，perimedullary arteriovenous fistula（AVF），dural AVFの3つに大別される^1,8,10,11)．

　Perimedullary AVFは前脊髄動脈，もしくは後脊髄動脈からの分枝が脊髄静脈路とAV shuntを形成するが，その分枝は脊髄軟膜動脈であることが多く，AV shuntは脊髄表面で形成される．

　今回，脊髄円錐部に複数の短絡路を形成し，さらに3椎体尾側の馬尾上でもAV shuntを形成した稀なperimedullary AVFの症例を経験したので報告する．

　Perimedullary arteriovenous fistula (AVF) is usually located on the surface of the spinal cord and is fed by the anterior spinal artery and/or the posterior spinal artery. We report a rare case of Conus perimedullary AVF with multiple shunt points including the cauda equina.

　A 68-year-old man presented with leg pain when walking long distances. Magnetic resonance imaging at the thoracic and lumbar level revealed multiple signal voids with marked cord signal change. Angiography showed the perimedullary AVF fed by the anterior spinal artery from the right T9 intercostal artery at the level of the conus medullaris and the fistula fed by the left lateral sacral artery from the left internal iliac artery at the level of the cauda equina. In the first surgery, we performed surgical interruption of feeding arteries from the filum terminale and coagulated AV shunt of the conus medullaris. However residual perimedullary AVF was found at the conus medullaris in the postoperative angiography. Secondary surgery was carried out to treat residual AVF. Follow-up angiography showed complete disappearance of all AVFs. Postoperatively, the patient`s symptoms were improved.

　Because the Conus perimedullary AVF has the characteristics of multiple feeding arteies,multiple shunt points,and complex venous drainage,it must be kept in mind that other fistula could exist in the cauda equina or filum terminale.