Finite Element Analysis Of The Implants Of Anterior Cervical Decompression Intervertebral Disc Replacement And Anterior Cervical Decompression And Interbody Fusion

Anterior cervical decompression surgery was conducted through in front of the cervical spine surgery.It basically can be divided into two kinds.O ne is anterior cervical discectomy and fusion,and the other is artificial disc replacement.Anterior cervical discectomy and fusion has already become a main treatment to lift the compression of the cervical spinal cord and cervical nerve root,the operation result is good,and it can make the sick cervical spine better stable.However,the secondary degeneration and instability of the adjacent spine segment after the surgery affect the long-term follow-up result.In order to solve the problems of the loss of mobility of segmental after traditional anterior fusion surgery,researchers began to use the artificial intervertebral disc to replace the sick disc to treat the cervical spondylosis,but the problem about the Prosthetic wear、fusion and heterotopic ossification often occur.Therefore it has become the focus and hot spots of research that the theory analysis on the two kinds of operation method and the evaluation for the effect on the biomechanical characteristics of the implanted devices,and it has a certain clinical application value.The three dimensional model of the inferior cervical vertebrae motion segment and the surgical model of AC DF and ACDR are established based on the CT images and combined with image processing software,which include cortical bone,cancellous bone,rear bony unit,fiber annulus matrix,collagen fibers,nucleus pulposus,cartilage endplate,five kinds of ligaments and other cervical structure.Use the finite element method and load torque on nondestructive model and operation model from different direction,make some comparative analysis on the biomechanical characteristics of the range of motion,intervertebral disc stress and the ligament tension and the mechanical properties of the implantation of prosthesis under status of flexion,extension,lateral bending and axial rotation.The main research contents and results are as below:1)Based on the C T images and the idea of the Grid envelope,mesh the cervical spine C4/C6 segment,build up the intact inferior cervical vertebrae C4/C6 segment Non-linear three-dimensional finite element model,compare the result of calculation to results of the in vitro experiments and finite element,verify the reliability of the model.2)According to the surgical model of ACDF and AC DR,build up three kinds of operation scheme on C5/C6 cervical disc degeneration: finite element models after ProDisc-C,DISCOVER artificial disc replacement and after ACDF,Two kinds of operation conditions are discussed about the effect of the biomechanical characteristics of inferior cervical vertebrae,arrive at a conclusion that Fusion surgery postoperative segmental decreased significantly than that of normal model,artificial disc replacement can guarantee the adjacent right range,ease of segmental degeneration.Make the analysis and evaluation about the stability of the cervical spine after two different artificial disc replacement and the mechanism of Wear and settlement of implant prosthesis,and it is significant for the design of artificial disc that is more accord with human body physiology and the clinical effect.