A Robust Method to Characterize Vertebral Geometry In Vivo

Wolff’s law postulates that bone will grow in the direction principal stress, as an effect of adaptation to this loading environment, and therefore will adjust their shape to prevent physiological imbalance. Altered geometry can be a mark of disease progression and degeneration just like a biomarker. For functional reasons, the vertebral body as a bone is not immune to these changes in geometry. Previous work in the literature has documented vertebral body geometry characteristics with age [1], its contribution to lordosis changes [2] and detected some asymmetric features [3]. These few descriptions available in the literature are limited due to their planar approach (radiography or individual CT slice cuts) [1, 2] or use of manual metrology devices that are subject to operator error, which might compromise its repeatability [3]. Based on the Wolff’s law premise, the hypothesis for this study is that a known alteration — spinal degeneration — of the spine configuration (lordosis) will also have an effect on the shape of the vertebral bodies. A common byproduct of spinal degeneration is also the presence of osteophytes in the intervertebral junction. To the best of the authors’ knowledge, no study has attempted to characterize hypothetical changes in vertebral geometry as in a population of low back pain symptomatic/ asymptomatic volunteers in vivo. The aim of this study is to prove said hypothesis by applying an accurate imaging technique that is insensitive to osteophytes and able to measure the vertebral body using subject-specific CT-based 3D models.