The Biomechanical Research On The Changes Of C_3/4 Morphological After C_5/6 Cervical Artificial Disc Replacement

Objective To reveal the morphological changes of C3/4 intervertebral foramena after the extripation of vertebral pulp and the replacement of artificial cervical intervertebral disc, and explore the mechanism in order to provide the academic evidence for the choose of the therapy of cervical intervertebral disc degeneration.Method There are 11 fresh examples obtained from men's cervical vertebra ,including the segments of C3 to T1 .Put the displacement pick-up into the C3/4 intervertebral space ,and respectively load axis pressure(0-160N)homolateral-bending(0-1.5Nm)oppositeside-bending(0-1.5Nm),back-extending(0-1.5Nm),anteflexion(0-1.5Nm).After having measured the morphological changes of C3/4 intervertebral foramena in C5/6 intergrity group, discectomy group and replaced group ,compare the change in different groups .The experimental data is analysed by the SPSS 11.0 software and the size of test is a=0.05.Result 1. The height and the width of intervertebral foramena in C5/6 intergrity group,discectomy group and replaced group are decreased under the load of 75N or 0.75Nm than those under the load of 150N or 1.5Nm in the circumstances of axial-bending,homolateral-bending and back-extending .But when in the opposite side-bending and inflexion ,these heights and widths are increased under the load of 75N or 0.75Nm than those under the load of 150N or 1.5Nm The differences have statistical significance (P＜0.05). 2.2. It has statistical meaning that under the same load of axial-bending,back-bending and homolateral-bending ,the ROV in height and the width of C3/4 intervertebral foramena pre- or post- loading in the discectomy group having vertebral pulp removed are increased than those in the intergrity group and the replaced group (P＜0.05). 3. The ROV in height and the width of C3/4 intervertebral foramena pre- or post-loading under any five circumstances have no difference between the artificial intervertebral disc replaced group and the intergrity group, but there was no statistically significant difference (P＞0.05)Conclusion 1. The intervertebral foramina change greatly under different positions: enlarged in flexion and opposite side- bending,diminished in axis, back-bending and homolateral- bending.2. To compare the effect on the C5\6 inter-foramina between the-ADR,discectomy group with the biomechanic method: there was no diference between the C_5\6 ADR and integrity group,But the there was significant diference between the integrity group and discectomy group3.The artificial disc has the function of disc functional reconstruction, and has no bad effect on the C3/4 intervertebral foraminal pore size.