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BACKGROUND: There is a high similarity of the cervical vertebrae between rhesus monkeys and human, both in terms of the number of cervical vertebrae and the anatomical structure of cervical vertebrae, especially the uncinate joints, which are unique to the cervical vertebrae, so they can be used as an ideal animal experimental model. However, there are few reports on the mechanical comparative study between the two. OBJECTIVE: To establish the finite element model of adult human cervical vertebra and adult rhesus monkey cervical vertebra, to compare the characteristics of stress and displacement of the uncinate joint between human and rhesus monkey cervical vertebra under six working conditions by means of finite element analysis, and to provide theoretical basis for clinical vertebral replacement. METHODS: A 40-year-old adult volunteer and a 7-year-old adult male rhesus monkey were scanned by spiral CT. The original cervical vertebra CT data were introduced into Mimics 21.0 to establish a preliminary three-dimensional model. Through the optimization, assignment, assembly and other tissue grids of each segment of cervical vertebra, intervertebral disc, ligament and so on, the cervical vertebra finite element model was constructed by Abaqus, and 75 N additional load and 1 N·m external force couple moment were loaded on the model. Comparative mechanical analysis was carried out under six working conditions of flexion, extension, lateral area and rotation, in order to find the mechanical change trend and difference between them. RESULTS AND CONCLUSION: (1) Both human and rhesus monkey cervical vertebrae had the unique structure of uncinate joint of cervical vertebrae. Through finite element modeling, the stress and displacement changes of the uncinate joint between them were basically consistent, and the stress and displacement concentration points were all at C5. There was a significant difference between them. (2) However, the cervical vertebra of rhesus monkey can be used as the best candidate animal for clinical cervical vertebra animal model, and provide theoretical basis for artificial cervical vertebra replacement [ABSTRACT FROM AUTHOR]

BACKGROUND: Both rhesus monkeys and humans belong to primates, and their cervical vertebra structure, physiological function and living conditions are very similar to those of human beings. However, there are few studies on the finite element analysis of the whole cervical vertebra of rhesus monkeys. OBJECTIVE: To establish the C0-T1 finite element model of cervical vertebrae of adult rhesus monkeys and to make a comparative study between the finite element models of cervical vertebrae of adult rhesus monkeys and human cervical vertebrae in order to find out the difference. METHODS: A 7-year-old adult male rhesus monkey was selected and scanned by multi-slice spiral CT in the Imaging Department of the affiliated Hospital of Inner Mongolia Medical University in December 2019. The original CT data of cervical vertebrae were introduced into Mimics21.0 to establish a preliminary three-dimensional model, and the geometric structure of the model was optimized by Cero to get the simulation three-dimensional model of cervical vertebrae. The assembly model was imported into Hypermesh for tetrahedral gridding to divide the tissue grids of various segments, intervertebral discs and ligaments of cervical vertebrae. Then the finite element model of cervical vertebra was constructed by Abaqus&ANSYS, and the validity was verified by referring to the relevant finite element model literature. RESULTS AND CONCLUSION: The three-dimensional finite element model of cervical vertebra of rhesus monkey (including C0-T1 and six intervertebral discs and related ligaments) was successfully established, with a total of 536 215 elements and 461 915 nodes. The overall simulation of the model was high, and the fine structure was restored with high precision, resulting in a high biological simulation performance. Comparing the range of motion of this model with that of human cervical vertebra model, we found that the flexion and extension of this model were smaller than those of normal adults (P < 0.05), and left and right lateral bending of C2-3, C3-4 and C6-7 segments was smaller than the range of standard deviation as reported (P < 0.05). However, axial rotation showed no significant difference as compared with the value reported previously (P > 0.05). To conclude, there is a great difference in the exercise efficiency between the finite element models of rhesus monkey cervical vertebra and human cervical vertebra, which can provide a theoretical basis for the study of rhesus monkey cervical vertebra modeling. [ABSTRACT FROM AUTHOR]