PhD studentship, In vivo measurement of strains in intervertebral discs

I'm pleased to offer applications for a PhD studentship on measurement of strains in vivo in intervertebral discs at the University of Exeter. It will be co-supervised by myself on (the mechanics side) and Dr J Meakin (on the medical imaging side).

Experience with optical strain measurement (eg DIC, virtual fields method etc), reverse engineering problems and/or finite elements would be desirable. Tax free stipend of approx 14.5k GBP, funding only covers registration fees for EU nationals (ie non-EU nationals must find extra funding at circa 9k GBP per year for 3 years)

Contact me in the first place c.w.smith-at-ex.ac.uk

Chris Smith

- Project description -

Degenerative changes in the

intervertebral discs of the spine, although common due to natural aging, can

present as severe pain and biomechanical dysfunction which requires surgical

intervention. Determining the pattern of strain in the discs in vivo may allow us to elucidate the

biomechanical reasons why some people experience more severe disc degeneration

than others and help in developing appropriate treatment strategies and better

replacement devices. A potential method to measure in vivo strains is to

acquire magnetic resonance (MR) or computer tomography (CT) images of the discs

in and apply image analysis techniques such as digital image correlation (2D)

and digital volume correlation (3D). These methods, although used by other researchers

to measure surface strains on isolated discs, have not been applied to images

of the disc's interior which is markedly inhomogeneous.

The proposed project aims to develop experimental

and image analysis methods for use in

vivo using medical imaging methods. Images of isolated discs (from

non-human model such as equine) will be acquired using MRI and CT facilities in

Physics and Engineering. Mechanical testing rigs will be used to apply known

boundary conditions to homogenous phantom and real discs and image analysis will

be used to determine the pattern of strain distribution in the discs. Once the methods have

been developed they will be applied to 3D image data from human intervertebral

discs acquired in vivo to begin to

explore the normal variation in the patterns of strain distributions in discs

as the subjects change posture and support load.

The end point of this project will be

a suite of experimental and analytical methods validated for measurement of 3D

strains in intervertebral discs in vivo,

and publishable preliminary data on strain patterns in human subjects.

Successful completion of the project

objectives will allow subsequent research funding to be sought for a

neo-clinical project to measure disc strains in vivo in a variety of postures and loading situations, in healthy

subjects. This would determine if abnormally high strains are being experienced

in the discs of some subjects and allow correlation with clinical assessments

of accelerated degeneration.