A method for a mechanical characterisation of human gluteal tissue

Area of Science:

• Biomechanics
• Biomaterials Science
• Medical Imaging

Background:

• Immobilization commonly leads to pressure sores due to sustained tissue strain and stress.
• Computational simulations are valuable for analyzing tissue stress-strain distribution under loading.
• Accurate soft tissue material parameters are crucial for effective computational simulations.

Purpose of the Study:

• To develop an in vivo procedure for characterizing the material parameters of human gluteal skin/fat and muscle tissue.
• To enable more accurate computational modeling of tissue behavior under load.

Main Methods:

• Utilized magnetic resonance imaging (MRI) with an MRI-compatible loading device for in vivo data acquisition.
• Applied the inverse finite element (FE) method with derived data as constraints in an iterative optimization process.
• Parameterized and optimized material constants for skin/fat and muscle tissues using FE models.

Main Results:

• Established distinct material parameter sets for human gluteal skin/fat and muscle.
• Determined the long-term shear modulus for skin/fat (G_{infinity, S/F} = 1182 Pa) and muscle (G_{infinity, M} = 1025 Pa).
• Achieved a high correlation (R² = 0.997) between simulated and empirical values for the skin/fat-muscle tissue compound.

Conclusions:

• Successfully developed and verified an in vivo method for characterizing soft tissue material properties.
• The derived material parameters enhance the accuracy of computational simulations for gluteal tissue.
• This research contributes to improved understanding and prevention of pressure sores through advanced modeling.