Cortical bone thickening in Type A posterior atlas arch defects: experimental report

Background Context

To date, no information about the cortical bone microstructural properties in atlas vertebrae with posterior arch defects has been reported.

Purpose

To test if there is an increased cortical bone thickening in atlases with Type A posterior atlas arch defects in an experimental model.

Study Design

Micro-computed tomography (CT) study on cadaveric atlas vertebrae.

Methods

We analyzed the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry vertebrae with a Type A atlas arch defect and normal control vertebrae.

Results

The micro-CT study revealed significant differences in cortical bone thickness (p=.005), cortical volume (p=.003), and medullary volume (p=.009) values between the normal and the Type A vertebrae.

Conclusions

Type A congenital atlas arch defects present a cortical bone thickening that may play a protective role against atlas fractures.