Analytical Modelling of Load-Deflection Behavior Intervertebral Discs Subjected to Axial Compression by Exact Parametric Solutions of Kelvin-Solid Models

摘要

Analytical modelling of creep response phenomena of human and rhesus monkey intervertebral discs subjected to a constant axial compressive load was performed by utilizing Kelvin-solid models. Results for the three and four-parameter models were excellent with an average error for the model predicted strain values from the experimental data ranging from .465% to 11.4% (collective average of 2.314%) for the former model and 1.29% to 19.9% (collective ranging from .465 for the latter on the 47-human spinal segments considered. The 3-parameter model strain predictions were very nearly a 'best fit' to the experimental data, while the values for the mechanical properties (Young's moduli and viscosity coefficients) of the 4-parameter model were obviously not optimized to the observed data. In spite of the of the 'lack of optimization' the results suggest the latter model as being more appropriate for predicting compressive creep behavior of human spinal segments over the entire time range. Experimental datum from 59-rhesus monkey intervertebral joints were also analyzed, but by only the 2-parameter-solid model. Correlation of the mechanical properties and spinal behavior of human and rhesus monkey specimens appears possible.