Spinal facet joints: biomechanical evaluation for improved interventions

In the UK, four out of five adults suffer from back pain at some point in their life, the treatment of which costs the NHS over a billion per year and the UK economy £10 billion per year. When a surgical option is required (for example after an accident or because of abnormalities in the spine), the gold standard is spinal fusion, an invasive intervention designed to stop the motion of the affected spinal area.

One of the main issues with spinal fusion is that it increases the stress on other area in the spine, in particular on small cartilaginous joints called the facets. Even in a healthy person, the facets are often deteriorated but this rarely cause any symptoms. After spinal fusion however, the deterioration can increase and create new symptoms and long term pain for one in four patients.

There is an urgent need to define the type of patients and procedures for which fusion works best; and to improve devices so that this accelerated deterioration of the facets happens less often. The levels of initial deterioration between patients differs greatly and there is currently a lack of biomechanical evidence that takes into account these large variations when testing fusion devices.

To tackle these issues, this grant will develop novel testing methods and tools combining laboratory simulation with computer modelling. These methods will be used to predict the variation in the mechanical performance of a series of parameters in fusion devices at various levels of facet deterioration. This will enable the different interventions to be matched to different patient's characteristics.

In addition, the process of proving the accuracy of the testing methods will involve conducting tests at different levels of deterioration. The results from these tests will provide a greater understanding of how facet deterioration affects the biomechanical function of the spine. This knowledge will have the potential to inform the development of other more effective treatments for the spine and the new methods developed can also be applied to other joints in the body.