Research On Cervical Spine Modelling And Basic Issues Of Mechanical Visual Human Of China

With the strong development of high speed traffic and pace of life speeding up in modern society, as well as changes of working modes, more and more people are suffering with neck pains and cervical spondylosis. An overall improvement in standards of living for the patients, they pay more attention to their life qualities. It leads to soaring demands of spinal fixator and artificial spinal discs during the clinical treatments. Biomechanical models occupy an important position in cervical spine injury and trauma studies. Cervical spine has the complexity both in the geometry and constituents. The limits of ethnics and test methods make it hard to get more deep information from the experimental researches. Because of the excellent abilities in dealing with complexity models Finite Element Analysis (FEA) methods are widely used in biomechanics study of the spine.This dissertation is based on the key project"Mechanical Virtual Human of China (MVHC)"supported by National Natural Science Foundation. An anatomy accuracy detailed three-dimensional finite element model was well developed. Using this model a simulation of cervical spine with physiology load has been introduced and discussed. In older to get the deep understanding of the mechanics of trauma and injury on cervical spine a comparative research on the intact model, fusion mode and disc replacement model were simulated and discussed. The sEMG signals of three important muscles on the neck were collected. Signal processing methods were introduced and the relationship between sEMG and force were investigated. The main contents are listed as following:1. The modeling of human cervical spine musculoskeletal system was established based on cryosectional images and CT scans. A three-dimensional anatomy detailed cervical spine model was developed including: atlas, axis, and C3-C7 bone structures and ligaments; the line models of 25 pairs of neck movements related muscles which classified into 9 groups.2. The three-dimensional finite element model of cervical spine has been developed. According to relationship of CT Hounsfield value and Young's modulus, the mean Young's modulus of vertebrae cancellous bone and posterior element were calculated. The soft tissues and joints were rebuilt referring to the literatures. The modeling method of soft tissues and joints were discussed.3. Validation of current finite element model was carried out by comparing with the experiment results and former FE model from relative literatures. Discussions on the basic mechanics of cervical spine using FEA method were introduced.4. A multi-level lower cervical spine model of C3-C6 segments was isolated. Simulations of fusion and disc implant on C4-C5 level were completed. Advantages and disadvantages between the two methods were comparied and effects on the stability of cervical spine after the surgery were predicted.5. EMG signals of three important neck muscles were collected and processed by NDI motion capture system. Investigations of different muscle in different movements on neck were completed and EMG-force relationship was discussed. Meanwhile, the viability of muscle force predictive method using sEMG was discussed.The advantage of the three-dimensional finite element model we developed is the most detailed anatomy structure both geometrically and morphologically. Compared with former models the unsymmetrical 3D structure of current FE model can simulate the different situations of the neck much more really and reliable. It can be wildly for biomechanical applications and also provide a platform for further biomechanical researches on cervical spine.