As an important part of the human spine, the cervical spine has a complex structure and easily suffers from diseases. Analysis of the biomechanical mechanism of cervical spine structure using the finite element model is not only helpful for the diagnosis, treatment and prevention of cervical spine diseases but also has positive significance for the performance evaluation of cervical spine implants. In this paper, a method of establishing a cervical C2-C7 finite element model based on CT image data is studied. Through the preprocessing of cervical CT images, the C2-C7 three-dimensional finite element model of the cervical spine was established. The pure moment loads of 0.33 Nm, 0.5 Nm, 1 Nm, 1.5 Nm and 2 Nm were applied to simulate flexion/extension, and the moment of 1 Nm was used to simulate the left and right lateral bending and axial rotation of the cervical spine. The relative range of motion (ROM) between each vertebral body was calculated. At the same time, the stress on some segments under axial load was analyzed. The results were basically consistent with the experimental data of in vitro studies, which verified the validity of the model.

To investigate the biomechanical performances of artificial cervical disc (ACD) prostheses, many studies have been conducted, either with cervical sections of cadavers under physiological loads or with block-like testing fixtures obeying the ASTM F2346 standard. Unfortunately, both methods are almost impossible to utilize for accurate results of lifetime anti-fatigue experiments for at least 10 million cycles due to the difficulties in cadaver preservation and great deviations of natural cervical bodies, respectively. Based on normal human cervical structural features, a novel specimen fixture was designed for testing the fatigue behavior of ACD prostheses under flexion, extension, and lateral bending conditions, with aspects of both structural and functional bionics. The equivalence between the biomimetic fatigue-testing fixture and the natural cervical sections was investigated by numerical simulations and mechanical experiments under various conditions. This study shows that this biomimetic fatigue-testing fixture could represent the biomechanical characteristics of the normal human cervical vertebrae conveniently and with acceptable accuracy.