The ageing spine

Bioengineering technologies to predict fracture

The musculoskeletal system plays a major role in our daily activities and its function can define the quality of life as we age.  However, even healthy ageing may lead to a functional decline in the musculoskeletal system including bone and muscles. These age-related changes combined with diseases such as Osteoporosis (weakness in bone) or Sarcopenia (weakness in muscles) could increase the risk of falls and future fractures.

From an engineering point of view, bone fracture occurs when loading exceeds the strength. That is why engineers design any structure considering their ability to withstand load to avoid fracture. This simple idea has been the centre of numerous biomechanical studies to predict hip, spinal and wrist fractures. Although we have gained an enormous amount of knowledge regarding the strength of our bone using high-quality imaging technologies, we cannot easily measure the effect of the internal (e.g. muscles, ligaments) or external loadings (e.g. weight of an object) on our joints. Excessive joint loads may put our bone at risk of fracture regardless of its strength.

To better predict the risk of osteoporotic spinal fracture, as a bioengineer, I have been developing personalised and computational models to predict spinal loading during different daily activities since I joined Harvard Medical School in 2015. Another non-invasive method based on imaging technologies can be used to assess the strength of spinal elements (e.g. vertebra) non-invasively. Having quantified joint loading and the strength of vertebra enables us to describe where the peak number of fractures may occur along the spine. In addition, we can explain which muscle groups are responsible for such peak loading along the spine. Our research using state-of-the-art Bioengineering Technologies combined with imaging techniques could pave the path towards developing novel methods to assess and prevent spinal fracture based on personalised modelling approaches.

[Source: Dr Hossein Mokhtarzadeh, Harvard Medical School]