ABSTRACT
BACKGROUND: Our team has built finite element dynamic bone models of different parts, but how to ensure the model’s precision and effectiveness, there still needs further study.OBJECTIVE: To provide accurate biomechanics model of Digital Human. METHODS: The CT data of Virtual Chinese Human --the male No.1 (VCH-M1) were imported into the MIMICS13.1 software authorized by the Materialise Company, and then the outcome document was entered into the ABAQUS6.7 software to perform finite element analysis. The result was observed and then the effectiveness of the models was tested. RESULTS AND CONCLUSION: The “.lis” document was chosen in the finite element analysis software ABAQUS6.7. Three dimension models of cervicalt were acquired. The model has 10 465 panel points and 52 752 units. It is verified that this model is effective. Results confirmed that the biomechanics model of Digital Human can be calculated for meeting the revolutionary requirement of the future digital medical science.
ABSTRACT
Objective To discuss the TARP (transoral pharyngeal atlanto axioal reduction plate,TARP) stress distribution under the condition of atlantoaxial dislocation treatment with the TARP system and explore the possible suggestion for the further innovation of the TARP system.Methods A fixed Finite Element model was constructed for transoral atlantoaxial reduction plate system based on the CT digital data of the China Digital Human NO.1.The internal structure changes and the stress distribution of TARP system under different loads were imitated and analyzed.Results The results showed that,after the fixation of the TARP system,different parts of the atlantoaxial had different stress under anteflexion,extension,lateral bending and rotation,the internal fixation parts located mainly at the mid-part of the TARP(0.159 × 108 ～0.732 × 108 Pa) and the root of the screw(0.214 × 109 ～0.958 × 109 Pa).Beside that,when using anteflexion,the stress mainly focused on the articular surface of the atlantoaxial(0.512 × 107 Pa).As for extension,the stress mainly focused on the part between the lateral mass and anterior arch (0.582 × 107 Pa).While lateral bending or rotation,the stress mainly focused on the axial screw nailing path (0.287 × 109 Pa and 0.241 × 109 Pa).Conclusions Although different parts of the TARP plate have different stress,its maximum stress lied in the root of the screw.The stress of plate mainly focused on the mid - part,no matter in what state of motion,therefore,the root of the screw and the mid-part of the plate bore the biggest stress,their strength decided the fatigue property of the TARP system.
ABSTRACT
BACKGROUND: Although the fixed-point cervical vertebra rotating reduction has a notable treatment effect, yet it has not been deeply studied in the medical field. Some clinical surgeons feel difficult to make an accurate control on the power and rotatory joint position while operating, even results in iatrogenic injury. OBJECTIVE: To discuss the action mechanism of rotatory technique based on the central rotatory point of cervical vertebra fixed-point rotatory technique. METHODS: Samples were scanned through a 64-row spiral CT working platform at 1-mm layer distance. The picture's profilogram data were extracted from the image processing functional module in PHILIPS MEDICAL SYSTEMS, and then the three-dimensional structure of the upper cervical vertebra was reconstructed and displayed. Taking the axis spinous process peak (point A), odontoid process vertical axes (point B), and the midpoint (point C) of their link as the rotating axes (the rotating central point in simulation), spherical system on each point was set up. The intersection angle of the links between the axis' spinous process peak and the lower jaw, and between the odontoid process vertical axes and the lower jaw before and after rotation were all measured. RESULTS AND CONCLUSION: While applying fixed-point rotation of the cervical spine, the rotatory centre is the vertical axle center of the odontoid process, rather than the handy axis spinous process peak. The rotatory angle of the axle centre is larger than the observation angle. A new concept of fixed-axis rotation should be accepted and its principle should be comprehended in order to appropriately apply the cervical rotatory technique.