Evaluation and Validation of Thorax Model Responses: A Hierarchical Approach to Achieve High Biofidelity for Thoracic Musculoskeletal System

Abstract

As one of the most frequently occurring injuries, thoracic trauma is a significant public health burden occurring in road traffic crashes, sports accidents, and military events. The biomechanics of the human thorax under impact loading can be investigated by computational finite element (FE) models, which are capable of predicting complex thoracic responses and injury outcomes quantitatively. One of the key challenges for developing a biofidelic FE model involves model evaluation and validation. In this work, the biofidelity of a mid-sized male thorax model has been evaluated and enhanced by a multi-level, hierarchical strategy of validation, focusing on injury characteristics, and model improvement of the thoracic musculoskeletal system. At the component level, the biomechanical responses of several major thoracic load-bearing structures were validated against different relevant experimental cases in the literature, including the thoracic intervertebral joints, costovertebral joints, clavicle, sternum, and costal cartilages. As an example, the thoracic spine was improved by accurate representation of the components, material properties, and ligament failure features at tissue level then validated based on the quasi-static response at the segment level, flexion bending response at the functional spinal unit level, and extension angle of the whole thoracic spine. At ribcage and full thorax levels, the thorax model with validated bony components was evaluated by a series of experimental testing cases. The validation responses were rated above 0.76, as assessed by the CORA evaluation system, indicating the model exhibited overall good biofidelity. At both component and full thorax levels, the model showed good computational stability, and reasonable agreement with the experimental data both qualitatively and quantitatively. It is expected that our validated thorax model can predict thorax behavior with high biofidelity to assess injury risk and investigate injury mechanisms of the thoracic musculoskeletal system in various impact scenarios. The relevant validation cases established in this study shall be directly used for future evaluation of other thorax models, and the validation approach and process presented here may provide an insightful framework toward multi-level validating of human body models.

Modeling of active skeletal muscles: a 3D continuum approach incorporating multiple muscle interactions

“…For example, the quadriceps were modeled without considering contacts or other interactions between muscles ( Fernandez and Hunter, 2005 ). The common approaches to model interactions between anatomical structures include sharing nodes between the mesh of structures (e.g., the Global Human Body Models Consortium (GHBMC) extremity models ( Schwartz et al, 2015 ; Zeng et al, 2021b ), fixed constraint(s) between organs ( Fernandez et al, 2005 ), contact ( Stelletta et al, 2017 ), and combination of contact and springs ( Böl et al, 2011 ). Physiologically, the muscles of the lower extremity such as quadriceps are enveloped by their deep fascias, permitting relative sliding of the muscles because of their epimysium ( Stecco et al, 2008 ).…”

“…Third, regarding the characterization of multiple muscle interaction, the quantification of force transmission between muscles remains a challenge from both experimental and simulation perspectives. Although we believe that the presented cohesive contact approach is more efficient and realistic than other existing approaches ( Fernandez and Hunter, 2005 ; Böl et al, 2011 ; Schwartz et al, 2015 ; Zeng et al, 2021b ) to model organ interactions based on the performance compared to the limited available evidence, the interaction effects on the muscle forces have not been quantified since there is a lack of experimental testing data for validation thus far. Finally, the external fascia and skin were not considered in the current quadriceps model, so further research is needed to accurately represent the thigh to consider the muscle packing effect ( Stecco et al, 2008 ).…”

A Surrogate Model Based on a Finite Element Model of Abdomen for Real-Time Visualisation of Tissue Stress during Physical Examination Training

“…The simulations were set up in LS-Prepost (Livermore Software Technology Corporation—LSTC, Livermore, CA, USA) by using material properties validated for the flesh (i.e., simplified rubber/foam) in [ 27 , 28 , 29 ] to represent the lumped abdominal tissue, and those for the ribs (i.e., piecewise linear plasticity) in [ 29 , 30 , 31 ] (see Table 1 ). The liver was modelled as a visco-hyperelastic material with parameters reported in [ 32 , 33 ].…”

Explaining and predicting the increased thorax injury in aged females: age and subject-specific thorax geometry coupled with improved bone constitutive models and age-specific material properties evaluated in side impact conditions

“…Notably, the F05-O model was developed with mesh quality requirements to ensure numerical accuracy ( 11 ). The F05-O has undergone validation in various body regions, including the thorax, with specific focus on chest compression and the incorporation of hard tissue failure using element erosion ( 12 , 13 ). The material models for trabecular and cortical bone in the GHBMC models are isotropic with elastic-plastic response, and simulate material failure with an element erosion criterion, based on maximum principal strain threshold.…”