Development, Validation, and Application of a Parametric Pediatric Head Finite Element Model for Impact Simulations

Abstract

In this study, a statistical model of cranium geometry for 0- to 3-month-old children was developed by analyzing 11 CT scans using a combination of principal component analysis and multivariate regression analysis. Radial basis function was used to morph the geometry of a baseline child head finite element (FE) model into models with geometries representing a newborn, a 1.5-month-old, and a 3-month-old infant head. These three FE models were used in a parametric study of near-vertex impact conditions to quantify the sensitivity of different material parameters. Finally, model validation was conducted against peak head accelerations in cadaver tests under different impact conditions, and optimization techniques were used to determine the material properties. The results showed that the statistical model of cranium geometry produced realistic cranium size and shape, suture size, and skull/suture thickness, for 0- to 3-month-old children. The three pediatric head models generated by morphing had mesh quality comparable to the baseline model. The elastic modulus of skull had a greater effect on most head impact response measurements than other parameters. Head geometry was a significant factor affecting the maximal principal stress of the skull (p = 0.002) and maximal principal strain of the suture (p = 0.021) after controlling for the skull material. Compared with the newborn head, the 3-month-old head model produced 6.5% higher peak head acceleration, 64.8% higher maximal principal stress, and 66.3% higher strain in the suture. However, in the skull, the 3-month-old model produced 25.7% lower maximal principal stress and 11.5% lower strain than the newborn head. Material properties of the brain had little effects on head acceleration and strain/stress within the skull and suture. Elastic moduli of the skull, suture, dura, and scalp determined using optimization techniques were within reported literature ranges and produced impact response that closely matched those measured in previous cadaver tests. The method developed in this study made it possible to investigate the age effects from geometry changes on pediatric head impact responses. The parametric study demonstrated that it is important to consider the material properties and geometric variations together when estimating pediatric head responses and predicting head injury risks.

Prediction of skull fracture risk for children 0–9 months old through validated parametric finite element model and cadaver test reconstruction

“…Age effects on the skull material properties within 0-9 MO age group cannot be well established. Compared to other components of the pediatric head, skull material property was found to have much more significant effect on global and strain/stress responses than the brain material [23,24]. Test data on the material properties of pediatric brain are very scarce.…”

“…During the mesh morphing, head shape, size, and skull thickness were morphed according to model-predicted landmark locations and the skull thickness values at those locations for children with different ages and head circumferences. In this study, the material properties for different head components were assigned based on a previous study by Li et al [23][24][25] as listed in Table 1. The linear elastic model was used for the skull with a Young's modulus of 164.3 MPa.…”

Computational Modeling of Traffic Related Thoracic Injury of a 10-Year-Old Child Using Subject-Specific Modeling Technique

“…However, the morphed model matched the weight of the target subject fairly well, indicating the fact that the weight distribution in the morphed model was reasonable. The radial-basisfunction method has been widely used for mesh morphing on different types of subjects and different body regions in the past, 14 including the pediatric head, 19,20 the adult rib cage, 39 the femur, 18 and even the wholebody. 38 Therefore, we believe that this method is suitable for this study.…”

“…This method has been used previously to generate parametric, human FE models. 19,38 Thin plate spline function (u r ð Þ ¼ r 2 log r) was used as the basic function for the RBF, because it generated a smooth geometry with good mesh quality. 20 To conduct mesh morphing, 2967 landmarks were selected from the baseline and target models to define the deformation field, and then a landmark-based RBF interpolation was conducted to calculate the new coordinates of all elements throughout the body, including the skeleton and soft tissues.…”

Effects of Skull Stiffness on Intracranial Responses of a Child Head

“…Many child head FE models have been developed and validated by reconstructing the traffic accidents or cadaver experiments of children [2]. To a certain extent the effectiveness of evaluating the traumatic brain injury (TBI) by using the FE models depends on the proper selection of mechanical properties of head materials.…”