BACKGROUND
Degenerative Cervical Myelopathy (DCM) is a slow-motion spinal cord injury caused via chronic mechanical loading by spinal degenerative changes. A range of different degenerative changes can occur. Finite element analysis (FEA) can predict the distribution of mechanical stress and strain on the spinal cord to help understand the implications of any mechanical loading. One of the critical assumptions for FEA is the behaviour of each anatomical element under loading (its material properties).
OBJECTIVE
This scoping review undertakes a structured process to select the most appropriate material properties for use in DCM FEA. In doing so it also provides an overview of existing modelling approaches in spinal cord disease, and clinical insights in DCM.
METHODS
A systematic search was built for MEDLINE and EMBASE to identify all primary clinical studies of FEA in spinal cord disease (N=597). This was supplemented with citation search to retrieve the literature used to define their material properties. The quality of evidence was then appraised and shortlisted with respect to DCM material properties, and a final recommendation made. Clinical insights from DCM studies were only suitable for qualitative aggregation.
RESULTS
42 studies were included, 15 (36%) focused on DCM. Generally (33, 79%) the spinal cord was modelled as grey and white matter separately. 14 source articles were identified describing the material properties of the spinal cord, of which 3 were considered most relevant to DCM. DCM FEA suggests spinal cord loading is influenced by the pattern of degenerative changes but decompression alone (e.g. laminectomy) is sufficient to address this (versus e.g. laminectomy and fusion).
CONCLUSIONS
FEA is a promising technique to explore the pathobiology of DCM, but also extend imaging techniques. To facilitate this, we describe a structured process to shortlist material properties. However there remain uncertainties around the ideal approach and its clinical interpretation.