The viscoelastic responses of the human cervical spine in torsion: experimental limitations of quasi-linear theory, and a method for reducing these effects.
The dynamic torsional viscoelastic responses of the human cadaver cervical spine were measured in vitro. The quasi-linear formulation of time dependent behavior was used to describe and predict the resultant torque as a function of applied angular deflection and time. The performance of the quasi-linear model was good, reaching correlation at the 99% confidence level; however, it tended to underestimate hysteresis energy (mean relative deviation = -19.1%) and observed stiffness. This was in part due to difficulties in establishing the physical constants of the quasi-linear model from finite rate relaxation testing. An extrapolation deconvolution technique to enhance the experimentally derived constants was developed, to reduce the detrimental effects of finite rate testing. The quasi-linear model based on this enhanced derivation showed improved predictive ability and hysteresis energy determination.
Myers
B S
BS
Department of Biomedical Engineering, Duke University, Durham, NC 27706.
McElhaney
J H
JH
Doherty
B J
BJ
D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000502:physiology*; D003198:Computer Simulation; D004548:Elasticity; D006801:Humans; D008962:Models, Theoretical; D014102:Torsion Abnormality; D016474:Weight-Bearing / Q000502:physiology