[An experimental study on mechanical properties of fiber layers in anulus fibrosus of lumbar interverbral disc 4,5]

Abstract

We tested the mechanical properties of fiber layers in adult anulus fibrosus of lumbar interverbral disc 4,5. Aulus fibrosus of lumbar interverbral disc was delaminated by using microsurgical technique. 8 testing points were taken in each layer according to the fibers going and 5 testing specimens were taken from each testing point. The length was 15-20mm, the width 1-2mm, and the thickness 0. 1-0. 5mm. By using tension test,the relationship curves of stress and strain were tested, the fitting curves and equations were obtained, and then the elastic modulus, damage strain and damage stress were obtained. Therefore we knew the parameters and equations of mechanical properties of each testing point. We got the result that the elastic modulus of each testing point, along the radius from outside to inside, decreased with the increase of layers. The damage stress decreased linearly from outside to inside. The damage strains of the outside 9 layers increased slightly with the increase of layers, and the others were almost constants, i. e. 0.34 +/- 0.14. We get the conclusion that analus fibrosus of intervertebral disc has special mechanical properties corresponding with its functions, which is in a close relationship with lumbar vertebral diseases.