Changing Rules Of The Morphology Of Lumbar Vertebral In Osteoporosis

Osteoporosis is one of the senile diseases which is mainly harmful to the elderly. It is well known that osteoporosis is defined as a disease characterized by low bone mass and bone microarchitectural deterioration which makes the bone more fragile, consequently increases the risk of fractures. In this study we employed conventional radiography, bone mineral density ( BMD) , scanning e-lectron microscopy (SEM) and bone histomorphometry analysis of to 16 human lumbar specimens with different sex and age to investigate the characteristic of osteoporosis lumbar vertebrae and the influence to the spine.Material and MethodsSixteen human lumbar specimens ( L₁ - L₄ ) aged from 25 to 75 years (mean 59. 2 years) were studied. Each lumbar vertebrae specimen was taken anteroposterior and lateral X — ray examination under equal circumstances. They were divided into two groups including normal group ( NG) and osteoporosis group (OG) according to the change of numbers of trabecular network in the third lumbar vertebrae. Following observations were taken :(l)The average segit-tal diameter and the height (ha. hm. hp) of the vertebral body were measured. The deformation degree of the lumbar vertebral body was obtained from the deformation index and the ratio of height. (2) PA - BMD and L - BMD of the L₁ -L₄ lumbar vertebrae of all subjects with dual - energy X - ray absorptiometry (DEXA) (IQ Lunar, U. S. A. ) were measured to investigate the influence of appendix to the bone mineral density. (3)The ultrastractural changes of the trabecular area of lumbar vertebrae were observed with JSM - 840 SEM. (4) The specimen of cancellous bone and end - plate in lumbar vertebrae were sliced andstained with pollak and HE staining. Bone histomorphometry observations were made and the influence of osteoporosis to the end - plate was investigated.ResultsThe OG was compared with the NG. (l)The height of the vertebral body decreased and the body is mainly wedge - deformed. (2)The measurements of L -BMD decreased significantly while that of PA - BMD does not. ?Under the SEM, the trabecular in lumbar vertebrae is thinner and sharper than NG and perforates and disrupts with a wider intertrabecular distance. (J)Histological observation shows that bone histomorphometry in NG were significantly higher than those in OG, the end - plate is thinner, the calcificated - layer increased and loosen, the chondrocytes loosen and degenerate.Conclusion1. Biomechnical strength of vertebrae in osteoporosis cases reduce and is apt to compressed deformation.2. The measurement of L — BMD is more accurate than that of PA — BMD because the latter are easy to be affected by appendix.3. The abnormal reconstruction of bone trabecular ultimatly results in bone absorption, decrease of the strength of structure and high risk of fracture.4. Bone structural and morphological change in OG is one reason for decrease in mechanical strength leading to spine disease. The change of loading on osteoporotic vertebrae induce the and plate degenerated and further destruction of the intervertebral disc. Osteoporosis is one of inducing factors of intervetebral disc degeneration.