[Cervical myelopathy as a result of ossification of the posterior longitudinal ligament (4 cases)].

Ossification of the posterior longitudinal ligament was demonstrated in four caucasian males with progressive myelopathy. Such a condition is not uncommon in Japan, but has rarely been reported in caucasian subjects. It is not related to spondylarthrosis. Clinical course is usually protracted and can be worsened by mild trauma. Computerized tomography is the best diagnostic tool. Anterior decompressive surgery is theorically warranted in cases of severe myelopathy. Multisegmental laminectomy was performed on two patients, but was followed by little improvement. We discuss the relation between this condition and ankylosing spinal hyperostosis.