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The application of physiological loading using a dynamic, multi-axis spine simulator.
Timothy Patrick Holsgrove1, Anthony W Miles2, Sabina Gheduzzi2
1Centre for Orthopaedic Biomechanics, Department of Mechanical Engineering, University of Bath, Bath, BA1 7AY, UK ; College of Engineering, Mathematics & Physical Sciences, University of Exeter, Harrison Building, Streatham Campus, North Park Road, Exeter, EX4 4QF, UK.
Medical Engineering & Physics
|January 4, 2017
Summary
This study developed a novel spine simulator capable of applying dynamic, unconstrained moments with axial preload. This advancement improves in-vitro spine testing by closely mimicking in-vivo loading conditions for better research accuracy.
Area of Science:
- Biomechanics
- Spine Mechanics
- Orthopedic Research
Background:
- In-vitro spine testing requires accurate replication of in-vivo loading conditions.
- Applying dynamic, unconstrained moments with axial preload in-vitro is technically challenging.
- Existing methods often fail to fully capture the complex loading environment of the spine.
Purpose of the Study:
- To assess the capability of a custom-developed spine simulator.
- To apply dynamic unconstrained moments with an axial preload to spinal specimens.
- To improve the fidelity of in-vitro spine testing protocols.
Main Methods:
- A custom six-axis spine simulator was utilized.
- Dynamic moments (flexion-extension, lateral bending, axial rotation) were applied to porcine L5/L6 specimens at 0.1 and 0.3Hz.
- Load control was employed to minimize non-principal moments and shear forces, with a 500N axial preload.
Main Results:
- Non-principal loads were minimized to within load cell noise levels at 0.1Hz and 0.3Hz.
- Position control during axial compression-extension demonstrated qualitative similarity to in-vivo axial loads.
- The system successfully applied dynamic, unconstrained moments with physiological preload.
Conclusions:
- The developed spine simulator effectively applies dynamic, unconstrained moments with axial preload.
- This system enhances the ability to replicate in-vivo loading conditions in in-vitro spine studies.
- Future research will explore dynamic load vectors, multi-segment specimens, and injury/degeneration effects.
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