China Science

McDonnell,P; McHugh,PE; O”Mahoney,D

Abstract Vertebral fractures due to osteoporosis commonly occur under non-traumaticloading conditions. This problem affects more than 1 in 3 women and 1 in 10 men over a lifetime.Measurement of bone mineral density (BMD) has traditionally been used as a method for diagnosis ofvertebral osteoporosis. However, this method does not fully account for the influence of changes inthe trabecular bone quality, such as micro-architecture, tissue properties and levels ofmicrodamage, on the strength of the vertebra. Studies have shown that deterioration of the vertebraltrabecular architecture results in a more anisotropic structure which has a greater susceptibilityto fracture. Transverse trabeculae are preferentially thinned and perforated while the remainingvertical trabeculae maintain their thickness. Such a structure is likely to be more susceptible tobuckling under normal compression loads and has a decreased ability to withstand unusual or off-axisloads. Changes in tissue material mechanical properties and levels of microdamage due toosteoporosis may also compromise the fracture resistance of vertebral trabecular bone. Newdiagnostic techniques are required which will account for the influence of these changes in bonequality. This paper reviews the influence of the trabecular architecture, tissue properties andmicrodamage on fracture risk for vertebral osteoporosis. The morphological characteristics of normaland osteoporotic architectures are compared and their potential influence on the strength of thevertebra is examined. The limitations of current diagnostic methods for osteoporosis are identifiedand areas for future research are outlined.

Keywords Bone Density; Densitometry; Osteoporosis; Spinal Fractures; Spine

Annals of Biomedical Engineering
0090-6964, Volume 35, Issue 2, 2007, Pages 3-189