Design And Biomechanical Study Of Anatomical Pterygoid Shape Titanium Mesh In Anterior Cervical

Object：In order to improve the integral stability of anterior cervical titanium plate，interbody fusion cage and vertebrae,and also decrease the sinking rate of titaniummesh, and also to restore cervical physiological curvature and height effectively.According to the radiographic measurements of superior and inferior cervicalvertebral endplate gradients,the sum height of a single vertebral body and the twoadjacent intervertebral, and the angle of leading edges between two adjacent vertebralbodies which be separated by one vertebral body, we had successfully developed theanterior cervical Anatomical Pterygoid-Shape Titanium Mesh (APSTM) prototypeand biomechanical characteristics of APSTM have been evaluated as well.Methods：APSTM for the middle and lower cervical spine of Chinese people and itsbiomechanical test was studied. This experiment was divided into three parts. Part1:radiographic measurements. The purpose is to provide rational parameters fordesigning the APSTM.120normal cases of lateral radiographs of cervical vertebrawere included in this part. The superior and inferior cervical vertebral endplategradients, the sum height of a single vertebral body and the two adjacentintervertebral discs, and the angle of leading edges between two adjacent vertebralbodies which be separated by one vertebral body were obtained by use ofradiographic measurement. Part2: the design of anterior cervical APSTM: On thebasis of the radiographic measurements and references from home and abroad, theprototype of APSTM were designed. The material and functional characteristic ofAPSTM were also described. Part3: this part is biomechanical study of anteriorcervical APSTM. Five fresh cervical spine specimens randomly labelled1to5wereembedded and used to establish normal Control Group, completed biomechanical stability analysis by testing cervical vertebrae (C3-5) range of motion(ROM). Eachgroup was conducted on the intact specimens under2.0Nm moment. After finishedthe Three-Dimensional Motion(flexibility-extension, lateral bending, axial rotation)measurements of normal control group, then given the C4, C3/4, C4/5vertebrectomyand were used to establish instable group. When instable group test completed, eachinstable specimen was performed with “ilium autograft with anterior plate”,“titanium mesh with anterior plate”,“ordinary pterygoid shape titaniummesh”,”APSTM”, respectively and randomly. Then the ROM test of each specimenwith the above four different internal fixation will be done, Continuously, after ROMtest, the vertical displacement of each specimen will be measured under the enlargedgradually axial compress load (50N,100N,150N,200N,250N,300N), and verify thecapability of four kinds of apparatus which resist subsidence. Radiographicmeasurements and biomechanical test data, analyzed on SPSS19.0statisticalsoftware.Results：1. Measurements of the endplate gradients: as the growth of age, the cervicalsuperior endplate gradient and inferior endplate gradient are generally reduced.The measurements of superior endplate gradient showed C5>(C3or C4)> C7. Themeasurements of inferior endplate gradient showed C7is the minimum.2. The sum height of a single vertebral body and the two adjacent intervertebraldiscs: the height of the middle column is the highest, the anterior column is middle,the posterior column is lowest. Comparison among in different age groups, the sumheight of a single vertebral body and the two adjacent intervertebral discs wasdecreasing with the growth of age, generally is a downtrend. Intervertebral height ofmen is more than women; There is no statistical significance of the height amongdifferent intervertebral.3. The angle of leading edges between two adjacent vertebral bodies which beseparated by one vertebral body: there is no linear relationship between age andgender with the angles. Comparison all measurement groups, it has been found that Angle C2-C4>Angle C5-C7>(Angle C3-C5or Angle C4-C6).4. In the Three-Dimensional Motion experiment, ilium autograft with anterior plate,titanium mesh with anterior plate, ordinary pterygoid shape titanium mesh and theAPSTM can also maintain the stability of cervical spine in the ROM offlexibility-extension, lateral bending and revolution.5. Vertical Compression Load Experiment: Compared with the other threetraditional fixation methods, the APSTM is much stronger to resist subsidence.Conclusion：1. After the vertebrectomy, the internal fixation can significantly improve thestability of cervical spine. The anterior ilium autograft with titanium plate, titaniummesh with titanium plate, the ordinary pterygoid shape titanium mesh and the APSTMcan maintain immediate stability of the cervical spine.2. The APSTM has more advantages in resisting subsidence of the titanium mesh.And the operation of APSTM is simpler, the cost of APSTM is lower. It has a betterclinical application value.