Conjoined nerve rootsにjuxta-facet cystを合併した1症例

Juxta-facet Cyst Associated with Conjoined Nerve Roots:A Case Report

Ⅰ．はじめに

　MRIの普及によってjuxta-facet cystの報告が増加している．Juxta-facet cystは椎間関節から発生する囊腫性病変で，その形成機序については関節の変性から由来する慢性的な機械的ストレスが関与していると考えられている⁶⁾．一方，conjoined nerve rootsは神経根奇形であり，神経根奇形を有する患者は有意に周囲の骨奇形を合併し得ると報告されている⁹⁾．今回，われわれはconjoined nerve rootsにjuxta-facet cystを合併した1症例を経験したので，juxta-facet cystの発生とconjoined nerve rootsとの関係性について文献的考察を加えて報告する．

　We report a case of a patient with a juxta-facet cyst and conjoined nerve roots. A 66-year-old man presented with left leg pain from the past 4 months. Neurological examinations revealed L5 and S1 radiculopathy on the left side. Magnetic resonance imaging（MRI）detected a mass lesion located near the left intervertebral joint at the level of L5/S1 and canal stenosis at the level of L3/L4. A juxta-facet cyst was diagnosed by arthrography. We performed a curettage and resection of the mass, posterior lumbar interbody fusion at the level of L5/S1, and laminectomy at the level of L3/L4. Conjoined left L5/S1 nerve roots were observed during surgery. The patient recovered from the symptoms of L5 and S1 radiculopathy immediately after surgery. Postoperative review of the preoperative computed tomography images revealed bony abnormality in the L5/S1 joint. We speculate that the bony abnormality may be associated with the development of conjoined nerve roots and the juxta-facet cyst.