Biomechanical And Biological Study Of Hat Cervical Intervertebral Fusion Cage

Objective The purpose of study is to evaluate biomechanical effect of HCIFC. Methods In this in vitro biomechanical study, 48 goat cervical spines (C2-5) were tested in flexion, extension, axial rotation, and lateral bending with a nondestructive stiffness method using a nonconstrained testing apparatus, and three-dimensional displacement was measured. Autologous iliac bone and cervical spine intervertebral fusion cage were implanted according to manufacturers' information after complete discectomy (C3-4) was performed. Eight spines in each of the following groups were tested: intact, autologous iliac bone graft, Harms cage, Syncage C, Carbon cage and HCIFC. The mean apparent stiffness values were calculated from the corresponding load-displacement curves. Additionally, cage volume and volume-related stiffness was determined.Results The stiffness of the Syncage C was statistically greatest in all directions. After implantation of HCIFC, flexion stiffness increased as compared with that of the intact motion segment. There was no significantly difference in stiffness between HCIFC and Carbon cage. The stiffness of HCIFC was statistically higher than that of Harms cage in axial rotation and significantly lower in flexion, extension and lateral bending. Volume-related stiffness of all cages was higher than that of iliac bone graft. Harms cage was highest in volume-related stiffness of all directions. Conclusions HCIFC can provide enough primary stability for cervical intervertebral fusion.