脊髄梗塞を呈した頸椎椎間板ヘルニアの1例

A Case of Spinal Cord Infarction Caused by Cervical Disc Herniation

はじめに

　脊髄梗塞は稀な疾患であり，血管支配領域により前脊髄動脈，後脊髄動脈閉塞による梗塞，および静脈性梗塞に大別される。頻度の高いものが前脊髄動脈閉塞による脊髄梗塞であり，その原因は動脈硬化症に起因するものが多く，そのほかでは大動脈瘤，血管奇形，腫瘍塞栓，梅毒性血管炎，手術や血管造影による医原性，そして椎間板ヘルニアなどが挙げられている。今回われわれは，頸椎椎間板ヘルニアにより前脊髄動脈閉塞をきたしたと考えられた稀な症例を経験した。椎間板ヘルニアによる脊髄梗塞の発症機序についての文献的考察およびMRIと，血管造影を中心とした神経放射線学的所見の詳細な解析を行ったので報告する。

Abstract

　A 40-year-old previously healthy female was diagnosed with acute progressive paraparesis. Neurological examination revealed bilateral four-limb weakness predominant in the distal part of the upper limbs and superficial sensory impairment below the cervical region.

　T₂-weighted image on MRI showed an area of hyperintensity in the gray matter of the cervical cord with disc herniation at the C4/C5 vertebral level. Laboratory investigation showed no evidence of infections, autoimmune, inflammatory, or neoplastic causes. A follow-up MRI study 3 days after admission showed that the region of hyperintensity was had enlarged without contrast enhancement. Spinal angiography was performed 21 days after admission and demonstrated that the anterior spinal artery originated from the fourth segment of the left vertebral artery and occluded at the level of C4/C5, which coincided with the location of disc herniation. We hypothesized that she developed anterior spinal artery syndrome which caused disc herniation.

　Although we frequently encountered disc herniation, there are few cases developed spinal cord infarction.　We discuss the etiology and pathogenetic relation between disc herniation and spinal cord infarction.

(Received: January 9, 2007, Accepted: March 23, 2007)