頸椎黄色靱帯石灰化症の1例

A case of calcification of the cervical ligamentum flavum

I．はじめに

　頸椎黄色靱帯石灰化症は，脊柱管狭窄をきたして脊髄圧迫症状を呈し得る疾患であり，1976年に南光ら^23）により初めて報告されて以来報告例が増加している．しかし，ときに黄色靱帯骨化症と混同され，病因もいまだ解明されてはいない．われわれは，短期間に進行性の脊髄症状を呈した頸椎黄色靱帯石灰化症の1例を経験した．過去の報告例と併せ，両者の相違点を中心に考察して報告する．

We report a case of cervical myelopathy caused by the calcification of the cervical ligamentum flavum. A 42-year-old woman with gait disturbance and an epi-sode of dysuria was transferred to our hospital on June 30, 1994. Neurological examination revealed only a mild right hemiparesis.

A plain neck X-ray and a tomogram revealed a nodu-lar calcification in the posterior part of the spinal canal at the level of C5/6. Three dimensional computed tomography clearly demonstrated that the mass con-sisted of three nodular structures on the vertebral lami-na. Magnetic resonance images demonstrated severe compression of the spinal cord by the mass whose in-tensity was low. The mass was removed en bloc together with the ligamentum flavum and C5 and C6 lamina. The mass showed no continuity to the dura ma-ter. The calcification was confined within the ligament. The patient's neurological deficits were resolved two weeks after the surgery. X-ray diffraction study demon-strated the component of the mass was found to be pure hydroxyapatite.

Clinical features of calcification of the ligamentum flavum are reviewed from 85 reported cases including ours, and the difference between this calcification and the ossification of the ligament is emphasized. Calcifica-tion of the ligamentum flaum is a distinct clinical entity.