Ossification of the posterior longitudinal ligament (OPLL) in the cervical spine. Clinical, neuroradiological and neurophysiological study on 9 cases.

Ossification of the posterior longitudinal ligament (OPLL) in the cervical spine is considered to be uncommon in western countries, although widely known and studied in Japan. We report on 9 cases of OPLL cervical myelopathy investigated by x-ray films and cervical CT and by somatosensory evoked potentials. The patients reported spastic tetraparesis, sensory disorders of the limbs and, in one case, sphincter incontinence. Neuroradiological examinations showed that the posterior columns of the spinal cord were more affected than the roots. Our data suggest that OPLL is more frequent in the West than has so far been reported and that combined radiological and neurophysiological investigation ensures correct diagnosis and accurate assessment of the cord impairment.