The Biomechanical Research On The Changes Of Pressures In The Same Zygapophyseal Joint After Bryan Cervical Artificial Disc Replacement

Objective To explore the stress change in the same zygapophyseal joint after C_5/6 discectomy and artificial disc replacement, to provide theoretic evidences for the choose of the therapy of intervertebral disc disorders and the method of intervertebral disc functional reconstructionMethod Eleven healthy adult fresh-frozen multisegmental cervical spine segments (C₃ to T₁) were utilized in this investigation and biomechanically evaluated under the following C_5/6 conditions:(1)intact spine;(2)discectomy;(3)the Bryan Disc prosthesis implantation. The load(25N-150N) of neutrality and pure moments (0.25Nm-1.5Nm) of axial, flexion, extension, and lateral bending were applied on each group. The stress changes of the C_5/6 zygapophyseal joint was tested by modified cyclo-shaped miniature transducer .The data was analyzed by SPSS for windows 12.0, the statistic significance was set atα=0.05.Result 1. Under axial , anteflexion, and lateral bending loading, the disectomy indicated a significant decrease in the stress of the C_5/6 zygapophyseal joint compared to intac condition and CADR (P<0.05).2. Under extension loading, the disectomy indicated a significant increase in the stress of the C_5/6 zygapophyseal joint compared to intac condition (P<0.05). 3. There was no obvious diference between artificial disc replacement anddisc intact (P>0.05).Conclusion 1. There was no difference between the C_5/6 ADR and intact spine group which revealed the prosthesis had the effect of disc functional reconstruction. 2.The discectomy of the C_5/6 can increased the stress of the C_5/6 zygapophyseal joint and maybe it can Induce the degeneration of the Same Zygapophyseal Joint.