Bone Abstracts

The vertebral body microstructure of young individuals appears to be divided into three equally high horizontal regions: two adjacent to the endplates and one in the centre of the vertebral body. With age this subdivision of the vertebral microstructure seems to vanish. The aim of the study was to investigate the differences in the age-related changes in vertebral microstructure in the two regions.

Vertebral (L2) bone specimens from 41 women and 39 men aged 18–96 years with an even age-distribution were μCT scanned. The bone specimens were divided into two regions: one spanning the central third and another spanning the two remaining thirds using custom made software. Standard 3D microstructural parameters were determined in each of the two regions.

In both regions, BV/TV, Tb.N, and vBMD decreased significantly with age, SMI, Tb.Sp, and bone material density increased significantly with age, while Tb.Th was independent of age. In the central region connectivity density (CD) and the degree of anisotropy (DA) were independent of age, while in the sub-endplate region these two parameters decreased and increased significantly with age, respectively. The slope of the fit lines was significantly larger for CD, Tb.N, and DA in the sub-endplate region than in the central region. The age-related changes in CD, Tb.N, and DA differed significantly in the two regions.

The bone in the sub-endplate region was denser, more well-connected, and less mineralised, than the bone in the central region, and the trabeculae in the sub-endplate region was more closely spaced, more rod-like, and of similar thickness as in the central region. Finally, the 3D bone microstructural parameters change significantly differently with age in the two regions. Therefore, caution should be exercised when examining the age-related changes of the 3D bone microstructure of human vertebral bone.