ARCHITECTURE AND DISTRIBUTION OF CANCELLOUS BONE YIELD VERTEBRAL FRACTURE CLUES - A HISTOMORPHOMETRIC ANALYSIS OF THE COMPLETE SPINAL COLUMN FROM 40 AUTOPSY SPECIMENS

The objective of this study was to analyze the structure of cancellous bone and its significance for vertebral fractures. Therefore, the com plete spinal column from 40 autopsy cases (18 without diseases affecti ng the skeleton and 12 osteoporotic) was removed and sectioned in the sagittal plane to a thickness of 1 mm. A surface-stained block grindin g technique allowed combined two- and three-dimensional histomorphomet ric analysis, which included an evaluation of the trabecular bone volu me (BV/TV, in %) and the trabecular interconnection (TBPf, in mm). In addition, qualitative investigation of the structure of trabecular bon e was done. The distribution of trabecular bone volume within the spin al column of a normal skeleton shows a curve, with the highest values in the cervical spine and a decline in the thoracic and lumbar spine. Osteoporosis presents itself with a pathologically diminished trabecul ar bone volume, whereas the distribution within the spine is comparabl e to that of the controls. Osteoporotic patients show an apparently re duced trabecular interconnection. It is important that the measured va lues for TBPf are not only in general higher, but also more widely dis persed. The age-related decrease of trabecular bone mass is due to the transformation from plates to rods. This is quantitatively indicated by the close correlation of BV/TV and TBPf (P < 0.001, r = 0.85). The bone loss in osteoporosis is a loss of structure and a loss of whale t rabeculae, which is caused by perforations. It involves a gradual chan ge from normal bone. However, the polyostic heterogeneity in osteoporo sis is immense. These structural differences demonstrate the developme nt of regions of least resistance within the spine, serving as an expl anation of osteoporotic fractures. Due to the polyostotic heterogeneit y it is impossible to define a threshold mineral content for crash fra ctures by diagnostic measurements at any reference site.