Biomechanical characterization of the human pia-arachnoid complex using bulge inflation testing and the virtual...

Area of Science:

• Biomechanics
• Neuroscience
• Materials Science

Background:

• The cranial meninges protect the brain from injury.
• Accurate computational models require biofidelic mechanical representations of meningeal tissues.
• The pia-arachnoid complex, the two innermost meningeal layers, plays a key role in brain protection.

Purpose of the Study:

• To biomechanically characterize the human pia-arachnoid complex tissue.
• To investigate the in-plane mechanical properties of this tissue.
• To derive parameters for a modified one-term Ogden model.

Main Methods:

• Bulge inflation experiments on 29 pia-arachnoid complex samples.
• Application of the virtual fields method for parameter derivation.
• Characterization of tissue thickness inhomogeneity.

Main Results:

• Pia-arachnoid complex tissue exhibits inhomogeneous thickness (median 0.400mm).
• A bivariate normal probability density function characterized log-transformed parameters (mean μ=0.30MPa, α=36.97).
• The tissue's mechanical behavior is highly nonlinear, unlike linear models in current head models.

Conclusions:

• The nonlinear mechanical behavior of the pia-arachnoid complex is critical for accurate head models.
• Realistic biomechanical properties are essential for improving computational predictions of traumatic brain injury.
• This research provides foundational data for advanced head injury modeling.