Finite element analysis on the mechanical properties of a new integrated artificial axis

English Keywords:Integrated Artificial Axis  Axis tumor  Finite element analysis  Biomechanics

English Abstract:

  【Abstract】 Objectives: The mechanical properties of a novel Integrated Artificial Axis (IAA) were investigated using three-dimensional finite element analysis. Methods: To obtain the cervical Dicom format data (anterior cranial fossa to C7) of a healthy 21-year-old male volunteer by thin slice CT scan, and mimics software was imported for the three-dimensional reconstruction. Simulated complete C2 resection and three-dimensional finite element model of the integrated artificial cervical vertebra and the reconstruction with the modified T-shaped Harms cage were established. The 3D model of the upper cervical vertebra was adjusted by Ansys 14.5 finite element software to make it consistent with the experimental data of the Panjabi cadaver specimens, and the validity of the model was verified. Then, a compressive preload of 40N combined with a pure moment of 1.5N·m was applied to the superior of the occipital condyle to simulate flexion, extension, lateral bending and axial rotation respectively. The maximum stress and displacement of the prosthesis and the maximum stress on C3 endplate of the two sets of internal fixation system were measured. Results: Under four different situations, the maximum stress values of the integrated artificial axis system and the T-shaped Harms cage system were 199.79MPa, 472.52MPa, 239.96MPa, 403.45MPa and 820.47MPa, 848.98MPa, 492.24MPa, 804.12MPa respectively; the maximum displacement values of these two systems were 1.8734mm, 1.8887mm, 0.8121mm, 2.6758mm and 2.4268mm, 2.5195mm, 0.9731mm, 3.2075mm, respectively; the maximum stress values on C3 endplate of the two systems were respectively 4.5104MPa, 5.8427MPa, 4.0497MPa, 12.7230Mpa and 4.8444Mpa, 5.7976Mpa, 6.4343Mpa, 14.0820Mpa. Conclusions: The finite element mechanical analysis showed that the new integrated artificial axis prosthesis can provide sufficient fixation strength and stability after anterior cervical vertebrae reconstruction, and it has better stability and lower stress concentration comparing with the T-shaped Harms cage.