腰仙部移行椎の横突起による神経根障害の治療経験

Unilateral Far-Out Foraminal Entrapment of the Nerve Root Below a Lumbosacral Transitional Vertebra. Case Report

　腰仙部移行椎の横突起による神経根障害の1例を経験した．症例は74歳，女性で左殿部から左下腿後面痛を主訴で受診した．理学所見では左S1神経根障害を呈した．全脊柱撮影にて，腰仙部移行椎，仙骨翼と移行椎横突起との関節面形成を確認した．神経根造影にて左側に移行椎椎間孔外で，移行椎神経根が圧迫されている所見を認め，椎間孔外での神経根障害と考え手術を施行した．神経孔外の神経根を確認したところ，頭側から横突起骨棘による圧迫を認めた．術後早期に症状は消失した．本症例では神経根造影が診断に有用であった．

　We present a case of unilateral far-out foraminal entrapment of the nerve root below a lumbosacral transitional vertebra, together with a review of the literature. A 74-year-old woman seen for pain and numbness of the buttock and leg was found in plain radiography of the lumbosacral spine to have a transitional vertebra with unilateral articulation between the transverse process of the transitional vertebra and the ala of the sacrum (Castellvi's Ⅱ-A). Computed tomography and magnetic resonance imaging showed no apparent the cause. Selective radiculography indicated entrapment of the nerve between a lateral bony spur and the ala of the sacrum, resulting in a diagnosis of unilateral far-out foraminal entrapment of the nerve root by a bony spur. We decompressed the nerve root by removing a part of the bony spur. Immediately after surgery, her symptoms disappeared. In this case report, we discuss the usefulness of selective radiculography for far-out foraminal stenosis to find far-out foraminal entrapment of the nerve root with lumbosacral transitional vertebrae.