A universal spine tester for in vitro experiments with muscle force simulation

Area of Science:

• Biomechanics
• Biomedical Engineering
• Spine Research

Background:

• Understanding spine stability and mechanics is crucial for diagnosing and treating spinal disorders.
• Current methods may not fully capture the complex interplay of forces acting on the spine, particularly muscle forces.

Purpose of the Study:

• To introduce a novel apparatus for determining the quasistatic, three-dimensional, load-displacement characteristics of spinal specimens.
• To investigate the influence of applied muscle forces on spinal biomechanics.

Main Methods:

• Development of a versatile loading frame adaptable to various spinal specimens (lumbar, cervical, entire spine).
• Computer-controlled application of three force and three moment components, allowing for individual or combined loading.
• Continuous recording of displacements during load application and release to study creep and relaxation.

Main Results:

• The apparatus successfully characterized the load-displacement behavior of spinal specimens.
• Application of muscle forces was shown to significantly alter the load-deformation characteristics of the spine.
• Muscle forces also demonstrated a significant effect on intradiscal pressure.

Conclusions:

• The developed apparatus is a valuable tool for comprehensive spine biomechanics research and stability testing.
• Muscle forces play a critical role in determining the mechanical response and internal pressures within the spine.