半限制型人工颈椎间盘置换与植骨融合术后下颈椎生物力学的有限元分析

目的 研究Discover、Prodisc-C人工椎间盘置换术与植骨融合术后下颈椎活动度（range of motion, ROM）、椎间盘应力、韧带张力的生物力学特性以及植入假体力学性能的改变。方法 建立C5~6椎间盘退变3种手术方案：Discover、Prodisc-C人工椎间盘置换和自体髂骨植骨融合有限元模型，同时建立C4~7节段下颈椎原始模型。分析术后下颈椎C4~7节段在矢状面、冠状面及横断面上椎体的生物力学特性变化。结果 术后手术节段关节ROM变化：Discover模型增加12.7%~73.1%，Prodisc-C模型增加74%~98%，植骨融合模型下降55.8%~71.8%。Discover置换后上邻近椎间盘应力无明显增加，下邻近椎间盘应力在前屈、后伸、轴向旋转工况下减少33.2%~54.2%，囊韧带张力增幅比Prodisc-C置换后减少30%~40%。Discover假体最大应力（36.72 MPa）出现在前屈工况下，小于Prodisc-C假体的最大应力（42.66 MPa）。结论 人工椎间盘置换术可以保留手术节段的运动性能，Discover作为新一代人工椎间盘假体，在减少韧带负担和维持脊柱稳定性方面有所进步。研究结果可为颈椎前路融合手术和人工颈椎间盘置换术的临床研究提供理论依据。

Finite element analysis on inferior cervical spine biomechanics after semi-constrained cervical intervertebral disc arthroplasty and anterior cervical discectomy and fusion

Objective To study biomechanical properties such as range of motion (ROM), intervertebral disc stress, ligament tension of inferior cervical spinal segment after the treatment of Discover, Prodisc-C artificial intervertebral disc replacement, and anterior cervical discectomy and fusion (ACDF), as well as mechanical property changes of the prosthesis after implantation. Methods Three kinds of operation plan on C5-6 cervical disc degeneration were established: Discover model, Prodisc-C model and ACDF model, as well as C4-7 segment original model of cervical vertebra. Biomechanical property changes after operation in cervical spine C4-7 segment in sagittal, coronal and transverse section were analyzed. Results ROM changes of cervical segment C5-C6 were as following: in Discover model it increased by 12.7%-73.1%, Prodisc-C model increased by 74%-98%, ACDF decreased by 55.8%-71.8%. The stress of C4-5 intervertebral disc after Discover artificial disc replacement showed no obvious increase, while the stress of C6-7 intervertebral disc decreased by 33.2%-54.2% under flexion, extension and axial rotation conditions. The amplification of ligament tension in Discover model decreased by 30%-40% as compared to that in Prodisc-C model. The maximum stress of Discover model (36.72 MPa) appeared under flexion condition, which was smaller than that in Prodisc-C model. Conclusions Artificial disc replacement can help to keep movement performance for segment after surgery. As a newly developed artificial intervertebral disc prosthesis, Discover makes some progress in the aspect of decreasing ligament stress and maintaining spinal stability. The research findings will provide theoretical basis for the clinical study on ACDF and artificial cervical intervertebral disc replacement surgeries.