Development And Validation Of The Fe Model For The Three-year-old Pediatric Cervical Spine

Human cervical spine is the most susceptible body part. Pediatric cervical spine hassignificant differences with adult in such anatomy and morphology. Such differencesas more slender vertebrae, more lax ligament and more flat facet joint will usuallycontribute to pediatric cervical spine injury risk. As an important structure connectedto the head, the dynamic response of cervical spine has considerable influence on thatof the head. Therefore, the research on biomechanics about cervical spine is crucial tothat about pediatric cervical spine protection and injury mechanism.Based on CT scans from a3-year old normal developed boy without cervical trauma,the software of Mimics and Geomagic is used to process the point cloud data andreconstructed the3-D geometrical model, while the software of Hypermesh is used todevelop the FE models of intervertebral disc, cartilage, ligament and other soft tissues;grounded on the material mechanics experiments of adult cervical spine and scalingmethods, initial material parameters of pediatric cervical spine FE models areobtained. In addition, a specific scaling method for pediatric cervical ligaments isproposed in this thesis.The cervical segment FE models of C2-C3、C3-C4、C4-C5、C5-C6和C6-C7arevalidated against the quasi-static and dynamic pediatric cervical spine tensileexperiments from Luck, the quasi-static adult cervical spine flexion-extensionexperiments from Nightingale and the quasi-static adult cervical spine lateral bendingand axial rotation experiments from Yoganandan, based on scaling methods ofpediatric cervical spine responses from Irwin; the FE model of the whole cervicalspine is validated against the range of motion under0.1N· m flexion-extensionloadings published by Luck as well as the dynamic tensile and flexion-extensionexperiments of2.5-year and3-year old pediatric samples from Ouyang. It is indicatedthat the quasi-static and dynamic tensile stiffness, dynamic tensile failuredisplacement and force of the C4-C5segment FE model is consistent with that of theexperiments, the responses of the other segmental FE models under quasi-staticflexion-extension, lateral bending and axial rotation loadings are within the range ofbaseline responses or the experiment corridors, namely that all of the segmental FEmodels are biofidelic. Although the dynamic tensile force-displacement curve of the whole cervical spine FE model is similar to that obtained in the experiment in itsshape, the dynamic tensile failure displacement and force of the simulation is lowerthan that reported in the literatures and great differences exist between the range ofmotion of the simulation and experiments under quasi-static flexion-extension loading.The biofidelity of the3-year old pediatric whole cervical spine FE model remains tobe improved.