[Histopathological study of aging of the posterior portion of human cervical vertebral bodies and discs--with special reference to the early ossification of the posterior longitudinal ligament].

UNLABELLED

Ossification of the posterior longitudinal ligament ( OPLL ) of the cervical spine is a disease causing spinal canal stenosis and, henceforth , spinal cord compression. This ossification is found approximately in three percent of the adult Japanese, but it is also found to be present among Chinese, Korean and other South-East Asians, whereas the incidence among Caucasians was reported to be significantly low. The etiology of this interesting ossification is still unknown although multidisciplinary studies have been carried out in Japan in recent years. The purpose of the present study is to find an early ossification of the posterior longitudinal ligament of the cervical spine and to see its relationship with other chronological changes of the surrounding structures.

MATERIAL AND METHOD

One hundred and forty-one cervical spinal columns were obtained en bloc from C2 to C7 from the autopsied bodies at Juntendo University Hospital and at the Tokyo Metropolitan Medical Examiners' Office. There were 89 males and 52 females with a wide age distribution. A 66 year-old male case with advanced continuous OPLL died at Juntendo University Hospital was added to the study. The specimens were either cross-sectioned or sagittally sectioned, and studied soft-ray-roentgenologically and histopathologically.

RESULTS

There were specimens after the third decade of life showing micro-ossification along the midline of the posterior aspect of the vertebral body on cross-section as well as micro-ossification or hyperostosis adjacent to the posterior corner of the vertebral body on sagittal section. These micro-ossification or hyperostosis seemed to be a product of a physiological aging process, but could be considered as a precursor of the OPLL . The periosteum was well demonstrated on the posterior aspect of the vertebral body in the first two decades of life, but it became inconspicuous with age. In the adult spine there was no clear delineation between the deep layer of the posterior longitudinal ligament and the fibrous layer of the periosteum . The cambium layer looked absent on hematoxylin-eosin stain. However, on Giemsa stain there appeared a thin layer which would present increased cellular activity between the body and what appeared to be the fibrous layer of the periosteal. This layer was considered to be a 'sleeping cambium layer' for which it was named 'latent periostium layer (LPL)'.(ABSTRACT TRUNCATED AT 400 WORDS)