Cervical myelopathy due to ossification of the posterior longitudinal ligament: a clinicopathologic study.

A clinicopathologic study was done of a Japanese patient with symptomatic ossification of the posterior longitudinal ligament in the cervical spine. Post-mortem specimen showed characteristic distribution of degenerations at C5-6 segments similar to chronic cervical spondylosis or disk protrusion. The degenerative changes were confined to the ventral two thirds of the posterior and lateral columns. In addition to demyelination, loss of axons, and neuronal cell death, thickening of venular wall and fine capillary neovascularization strongly suggested chronic circulatory insufficiency. Spinal immobilization produced by the ossified ligament may have contributed to the long clinical course, lasting for 30 years. Review of literature showed that the myelopathy can be distinguished clinically and radiographically from that produced by cervical spondylosis.