The Designed Structure Of The TSFC And Finite Element Analysis

During the operation of the anterior cervical,decompression,interbody fusion and plate interfixation has come to be a common surgicall procedure for cervical disease.The principle of the operation is decompression completely and fusion,and the fixation by the plate is one of the method for fusion.With the advancing of the technique,more and more instrument has come to the area.In spite of the autograft or the anterior cervical plate,some disadvantage could be found in them.at present,The price of the imports is too high for our Chinese people,we design the Two Screws Fixed Cage.At the same time,we had done prelim analysis for finite element.Objective:1.The applied anatomy for lower cervical anterior fusion cage;2.We sought to test its biomechanical effect offered by Two Screws Fixed fusion Cage (TSFC )and to evaluate its feasibility.Methods:1.We measured the width and depth of upper lamina terminalis on dry specimen of C_3-7 by electronic vernier calipers;2.By the scanning on 30 healthy volunteers by MRI T2WI,we measured the height(anterior,middle,posterior) of the intervertebral space on C_3-7;3. According to the clinical request and The applied anatomy for lower cervical,we designed the TSFC for cervicl fusion;4.The cervical spine geometries were determined from CT images of a 25 years old healthy man.The finite element model(C5/6,cage and Screws) was constructed by the combination of software package Mimics 12.0,Geomagic Sudio 9.0,Ansys 10.0 and AUTO CAD.The anterior cervical spinal fusion procedures with TSFC were simulated in finite element software.5.Cervical ROM was calculated after C5 being subjected to moments 1.53Nm and C6 were rigidly fixed while loads were applied at the C5 for flexion; extension,lateral bending and axial rotation.the results was compared with literatures and to evaluate its biomechanical effect.Results:1.The width of the upper lamina terminali is 15.4±1.12-20.7±0.56mm, the depth of the upper lamina terminali is 14.5±0.45-17.8±0.55mm.The anterior height of the intervertebral space is 5.89±0.53-8.04±0.36mm;the middle height is 6.95±0.47-9.65±0.65mm;the posterior height is 4.42±0.38-5.00±0.35mm;2.The ROM decreased by 30%and when it was compared with the noninstrumented,a significant difference was seen(P＜0.05);3.There is no stress concentration after C5 being subjected to moments 1.53Nm.4.the stress concentration phenomenon occurs mainly in screws and C6 vertebrae in this experiment,especially in the flexion movement,the maximum stress that screws being subjected is 260.6Mpa;5.stress concentration region mainly concentrated at the junction of the screws-fusion cage-endplate. conclusion:1.The design of TSFC is fit for the demand of anatomy and biomechanics;2.As the TSFC has the function of pull out resistance and provides good environment for spinal fusion,it can supply enough primary stability for the anterior cervical spinal fusion.3.there will occer fatigue fracture at the maximum stress concentration region;4.We can promote cognition and prediction by use finite element model what is to suit evaluation a new type internal fixation devices. In this clinical comparative study 41 patients with CSM were treated after being divided onto two groups。21 patients from group A were treated with surgical and combination of Cervus and Cucumis Polypeptide injectide injection and Chinese herbs and Duhuo Jisheng Tang.the other 20 patients were treated with simple surgical operation(GroupB).According to evaluation of severity of myelopathy using Japanese Orthopedics Association(JOA) scores we assessed all patients before the treatment and after 2weeks,6 months.Results:Patients in Group A had an average recovering ratio 82.1%and a total good ratio 95.2%after treatment for 2 weeks.Patients in Group B had an average recovering ratio75.4%and a total good ratio95%after 2 weeks.All patients in Group A had an average recovering ratio 92.5%and a total good ratio 95.2% after 6 months.All patients in Group B had an average recovering ratio 82.0% and a total goodratio 95%after 6 months.After 6 months patients in Group A had better JOA recovering ratio than those in Group B(P＜0.05 =。Conclusion:Treatments for CSM by the method of surgical operation combined with Cervus and Cucumis Polypeptide injectide and Chinese herbs and Duhuo Jisheng Tang could treat patients better than treatments of single surgical.so it was considered a safe treatment method for cervical spondylotic myelopathy. The reasons of the good results might relate to that the combination therapy improve or reconstruct blood circulation for spinal cord and then nourish spinal cord better.