Abstract:

BACKGROUND: Currently, there are few studies on finite element model of multi-segmental cervical and no studies on finite element model of Hangman fracture.
OBJECTIVE: To establish three-dimensional finite element models of normal C2-4 segments and Hangman fractures in various degrees, as well as simulate and verify the models.
METHODS: CT scanning of the C2-4 segment was performed in an adult male volunteer in order to establish the three-dimensional finite element model of C2-4 segment using three-dimensional finite elements analysis software including ANSYS at computer workstation. The model included the vertebral body, arch of vertebra, intervertebral disc and the ligament. The Hangman fracture model was prepared by cutting off bilateral isthmus of C2, the anterior longitudinal ligament of C2-3 and part of the intervertebral disc based on this model. Range of motion (ROM) at three dimensions in six directions of C2-3 and C3-4 segments under simulated 50 N loading was calculated in normal or Hangman fracture models.
RESULTS AND CONCLUSION: C2-3 segment: ROM of the Hangman fracture + ligament intervertebral disc resection model was larger than that of the normal model in all directions, especially in directions of flexion and extension, however, the ROM was the same on rotation and lateral flexion to that of the normal model. C3-4 segment: the ROM of the two groups was similar, and the difference was no larger than 0.16°. The displacement results were basically consistent with those of the stress testing of the three-dimensional finite element models. The three-dimensional finite element models can be used for simulating biomechanics of Hangman fractures.