Three-dimensional Finite Element Analysis Of New Aliform Titanium Mesh Cage In Anterior Cervical Spine

Objectives1. To develop and validate a three-dimensional finite element model of the low cervical spine(C₄～C₆)by the combination of software package Mimics 10.01, Freeform and Ansys 9.0.2. Based on the intact finite element model, a model was generated by simulating anterior cervical Aliform titanium mesh cage fusion after C₅ corpectomy; To study the biomechanical efficiency of the Aliform titanium mesh cage by finite element analysis.3. To evaluate if the design of aliform titanium mesh cage is resaonable and how to improve and optimize .Methods1. The cervical spine geometries were determined from CT images of a 25year old healthy man. The finite element model was constucted by the combination of software package Mimics 10.01, Freeform and Ansys 9.0.Mean the range of degree motion was calculated after C₄～C₆ being subjected to loads of moments 1.8 Nm and 73.6N preload and C₆ was rigidly fixed while loads were applied at the C₄ for flexion, extension .For validation of the model, the range of degree motion was compared with the results by Moroney et al.2. Based on the intact finite element model, the model was generated by simulating anterior cervical aliform titanium mesh fusion and plate after C₅ corpectomy by Ansys 9.0. Of the aliform titanium mesh cage,von Mises stress,the stress distributions were analysed after loading of the model being simulated using multidirectional moment loads of 1.8 Nm combined with a compressive preload of 73.6N in flexion, extension, lateral bending and axial rotation.Results1. The model consists of 110230 nodes and 68368 elements, and correlated well with the results by Moroney et al; The model was generated by simulating anterior cervical aliform titanium mesh fusion and plate after C₅ corpectomy.2. The stress concentrated on the basilar part of aliform plates when flexion ,lateral bending and axial rotation load were applied to the model, especially axial rotation. while the stress concentrated on the around area of screw hole in aliform plate when extension load was applied to the model; The stress of bone graft distributed uniformly and the stress value was suitable for bone grafe fusion.Conclusions1. The a three-dimensional finite element model of the lower cervical spine realistically simulates the complex kinematics of the lower cervical spine(C₄～C₆) region which can simulate the natural condition and facililate the further biomechanical research.2. The result come out that the contour design of aliform titanium mesh cage is consistent with biomechanis principle and the stability, intensity and stress distribution are reliable.However, because the stress concentrated on the area around screw-hole of aliform plates and the basilar part of superior and inferior aliform plates,the design of aliform plate need to be optimized partly.