[Morphological observations on trabecular microfractures in the lumbar vertebrae (author's transl)]

Trabecular microfractures have been described in the bodies of the lumbar vertebrae (Vernon-Roberts, 1973). The author started this study to clarify the possibility of the participation of such microfractures in the physiological remodelling of the vertebral body. The number, distribution and microstructure of the trabecular microfractures were assessed in the 5mm thick macerated slices of lumbar vertebral bodies taken from 36 post mortem subjects mainly above the age of 40 years. The characteristics of the vertebral bodies with microfractures were further examined by a semiquantitative histology and soft X-ray radiography of the 2mm thick macerated specimens. Trabecular microfractures had little displacement. The repair process, however, might be very slow. The number of microfractures were increased in the vertebral body with decreased bone mass. It was, however, predominantly denoted in the almost normal vertebral body comparing with the deformed one. Microfractures were not regularly distributed within each vertebral bodies. The appearance of microfractures was therefore a little different from the usual fatigue fracture. In conclusion, the trabecular microfracture might be caused by relatively hyper-loading that could not be resorbed in normal turnover of formation and resorption as a remodelling process. The healing of microfractures might be related to the compensatory hypertrophy of the trabeculae.