Parametric Modeling And Injury Study Of Children's Neck Under Collision Conditions

Vehicle crash is an important cause of cervical spine injury in children.More than half of spinal injuries in children occur in the neck.At present,there are relatively few studies on cervical spine injury in children.At the same time,due to the differences of cervical anatomical structure and the complexity of cervical spine structure in children of different ages,it is difficult and long-term to model cervical spine in children.Therefore,it is of great significance to develop a fast parameterized model of cervical spine and to study cervical spine injury in children of different ages.In this study,the Mimics image processing,Geomagic geometric reconstruction,Hypermesh geometric partitioning,and Truegrid block projection method are used to complete the segmentation of high quality hexahedral mesh in adult vertebrae.According to the anatomical structure,the cervical soft tissue structures were established in Hypermesh,and the materials of each tissue were defined.In the process of choosing cancellous bone material model,the compression test of cancellous bone in piglets was carried out to provide basis for choosing cancellous bone material model in human body.Finally,a finite element model of adult cervical spine based on anatomical structure was established.Based on the established finite element model of adult vertebrae,the marker points are selected in the reference finite element model of cervical vertebrae and the target geometry,and the interpolation function based on radial basis function is constructed.The finite element model of the reference vertebra was transformed into the vertebral target geometry of a 10-year-old child,and a finite element model of the cervical spine of a 10-year-old child was finally established.In order to compare the risk of cervical ligament and annulus injury in 6-year-old and 10-year-old children with adult C6-C7,and the risk of injury of cervical ligament and annulus in 6-year-old and 10-year-old children under 30 km/h frontal collision conditions.In this paper,the finite element model of cervical spine in 6-year-old children was improved and the vertebral joints and cervical muscles were reconstructed.Based on the cadaveric experimental data in the literature,quasi-static flexion and extension of the cervical spine of 6-year-old children,10-year-old children and adults C0-C2,C4-C5 and C6-C7 were validated.Based on the experimental data of volunteers in the literature,the finite element model of cervical spine with muscle was validated by macrokinematics.The validation results show that the finite element models of the neck of 6-year-old,10-year-old and adult have high biofidelity.Finally,the risk differences of Macro-motion and soft tissue injury of C6-C7 cervical spine segment between 6-year-olds,10-year-olds and adults under different kinds of bending loads were studied,and the difference of neck response between 6-year-olds and 10-year-olds under 30 km/h frontal collision conditions was analyzed.It is found that the angular displacement response of C6-C7 cervical spine becomes smaller and smaller with the increase of age under the same load at the Macro-motion level,and the more difficult it is to produce excessive motion.At the tissue level,the risk of ligament injury is related to the type and age of the load.In the lateral bending condition,the annulus injury is most likely to occur.The risk of injury of cervical ligaments in 6-year-old children was significantly higher than that in 10-year-old children under 30 km/h frontal collision condition,but the damage risk of annulus is relatively smaller.