Three-dimensional finite element analysis of the zygapophyseal joints following artificial lumbar disc replacement / 中国组织工程研究

ABSTRACT

BACKGROUND: With deepening of spinal biomechanics, artificial lumbar disc replacement is considered to be the optimal choice for treating degenerative lumbar disease. However, studies concerning biomechanics of artificial lumbar disc are insufficient. OBJECTIVE: To establish the three-dimensional (3-D) finite element model of artificial lumbar disc replacement and to explore the effects of artificial lumbar disc replacement on zygapophyseal joints using biomechanical analysis. METHODS: Based on normal 3-D finite element model of lumbar motion segment, L4-5 intervertebral disc, superior and inferior endplates were removed, and then, the model of SB-Charite Ⅲ disc prosthesis was added, which remained annular fibrosus and ligaments at L4-5 intervertebral space. Thus, 3-D finite element model of L4-5 segments artificial lumbar disc replacement was constructed. Biomechanical analysis of this model was processed under axial load, forward flexion, lateral bending or posterior extension moments. The stress data were contrasted with the normal 3-D finite element model of artificial disc replacement. RESULTS AND CONCLUSION: After artificial lumbar disc replacement, the data of biomechanical analysis indicated ①There was no significant differences between the zygapophyseal joint and normal segment of stress under axial load (P > 0.01).②Compared with normal segment, the stress of anterior, posterior of upper and lower vertebral body and bilateral zygapophyseal joint had no obviously difference under forward flexion and posterior extension moments (P > 0.01). ③The stress differences between the both sides of upper and lower vertebral body and bilateral zygapophyseal joint were not significant under lateral bending moment (P > 0.01). Artificial lumbar disc replacement can keep the stress of motion segment at normal level, which can meet the needs of spinal functional reestablishment.