ABSTRACT
Objective To explore the motion features of cervical spine based on continuous X-ray images.Methods The cervical spontaneous continuous multi-frame sagittal images from flexion to extention positions were selected from cervical spondylosis patients (patients group) and healthy adult (normal group).After preprocessing and registration,the trajectory of single vertebral body were recorded,and the feature points of each vertebral body were extracted.Meanwhile,the rel ative geometry parameters and movement rate were calculated.Results The motion trajectory of patients' cervical spine C4-6 were different from healthy people.The angles between the left edge curve of the vertebral body (C4 and C5 vertebra) and the baseline of patients group were smaller than those of normal group in flexion position (all P＜0.05).There were instability in the movement of C4 vertebral body in patient group,and the volatility of the angle change,the rate of change and the frequency were larger.The relative position change of the adjacent single vertebral body in the patient group are smaller.Conclusion Through the preprocessing,registration,parameter extraction and result analysis,the changes of functional features in cervical spondylosis patients are truly reflected.And it also provides a new idea for dynamic analysis of cervical vertebrae based on X-ray images.
ABSTRACT
Objective To study dynamic characteristics of human lumbar spine using three-dimensional finite element method. Methods Finite element model of lumbar spine (L1~5) was developed and validated based on CT images, and the modal analysis was also conducted. Results A total of top 30-order modal parameters were extracted to obtain dynamic characteristics of the lumbar spine under free boundary conditions. Resonance frequencies of the model were concentrately distributed, but the amplitude of each order varied greatly. Amplitude near L5 segment was much larger, indicating L5 was easily to be injured. This lumbar modal analysis could provide a basis for its further dynamic analysis. Parameters such as natural frequency, modal shape and vibration amplitude of the lumbar spine would be helpful for both lumbar dynamic analysis and optimal design of man-machine interface mechanical equipment.