Modeling and optimization of cranial suture anisotropic material properties using a response surface methodology

Area of Science:

• Biomechanics
• Computational modeling
• Craniofacial anatomy

Background:

• Cranial sutures are complex structures crucial for skull development and integrity.
• Understanding suture mechanics is vital for diagnosing and treating craniosynostosis and skull deformities.
• Previous models often simplified suture material properties, limiting predictive accuracy.

Purpose of the Study:

• To develop and validate a transversely isotropic finite element (FE) model of the cranial suture.
• To predict suture mechanics using ex-vivo data from swine internasal sutures.
• To investigate the role of material anisotropy and regional geometry in suture mechanical behavior.

Main Methods:

• Constructed a 2D displacement-controlled FE model using microcomputed tomography (μCT) images.
• Quantified collagen fiber orientation from histological sections.
• Optimized transversely isotropic material parameters using response surface methodology (RSM) and experimental data.
• Validated model predictions against ex-vivo experimental force-displacement measurements.

Main Results:

• The transversely isotropic FE model accurately predicted swine internasal suture mechanics.
• Shear and Young's moduli significantly influenced the suture's force response (p < 0.05).
• Material anisotropy reduced strain energy within the suture compared to isotropic models.
• Regional variations in suture geometry affected fiber alignment and mechanical behavior.

Conclusions:

• Developed a validated 2D FE model incorporating transversely isotropic material properties for cranial sutures.
• The model captures region-specific mechanical responses by integrating histology-based collagen fiber orientation.
• This approach provides new insights into the structural role of anisotropy in cranial suture mechanics.