RESUMEN
Objective To establish 3D finite element of human cervicothoracic spine C5-T2 based on CT images, and explore effects on stability of the cervicothoracic spine after total spondylectomy (TS) by using various combinations of internal fixation devices (pedicle screw, titanium mesh, steel plate), including the stress distributions on these internal fixation devices. Methods The intact finite element model of cervicothoracic spine C5-T2 was established and validated by comparing the model’s range of motion (ROM) with that of other in vitro experiments. Then four reconstruction models after TS of cervical spine segment C7 were established: TM+AP+DPS model (titanium mesh + anterior plate + posterior double-segmental pedicle screw), TM+AP+SPS model (titanium mesh + anterior plate + posterior single-segmental pedicle screw), TM+DPS model (titanium mesh + posterior double-segmental pedicle screw), AP+DPS model (anterior plate + posterior double-segmental pedicle screw). ROM of each reconstruction model under flexion, extension, lateral bending and rotation and stress distributions on these internal fixation devices were then analyzed. Results ROM of the reconstruction segments was greatly reduced by over 93% as compare to that of the intact model. Stress concentration phenomenon appeared on the titanium mesh in the TM+AP+SPS model. Conclusions The fixation effects of four reconstruction models are similar. Stresses on 3 DPS fixed-models are more evenly distributed, indicating that the overall stability of DPS fixed-model is superior to that of SPS fixed-model.