A data-driven microstructure-based model for predicting circumferential behavior and failure in degenerated human...

Area of Science:

• Biomechanics
• Biomaterials Science
• Computational Biology

Background:

• Degeneration of the annulus fibrosus (AF) presents challenges in predicting its mechanical behavior.
• Understanding AF mechanics is crucial for disc health and injury risk assessment.

Purpose of the Study:

• To develop and validate a novel 3D continuum-based model for predicting the mechanics of degenerated human annulus fibrosus.
• To integrate microstructure, hydration, and age-related factors into a predictive framework for AF mechanics.

Main Methods:

• Developed a fully 3D continuum-based model incorporating hydration state and multiscale structural features of the AF.
• Established a data-driven correlation between disc degeneration grade, age, and regional variations in AF composition and mechanics.
• Quantitatively evaluated model predictive capabilities against experimental data, focusing on circumferential behavior and failure.

Main Results:

• The model accurately replicated experimental data for stiffness, transverse response (Poisson's ratio), and ultimate properties across different AF regions.
• Simulated reduction rates in stiffness and failure properties due to degeneration aligned with experimental findings.
• Inner AF regions showed significant stiffness reduction (34.63%), while outer regions showed less change; failure stress decreased substantially in both regions.

Conclusions:

• The proposed microstructure-based framework significantly enhances predictive accuracy for AF mechanics across degeneration levels.
• The model provides deeper insights into disc health, injury risk, and the impact of degeneration on disc integrity.
• This approach offers a robust foundation for future research and improved clinical assessments of disc-related conditions.