Biomechanical evaluation of pedicle screw-based dynamic stabilization devices for the lumbar spine: a systematic review.
Biomechanical evaluation of pedicle screw-based dynamic stabilization devices for the lumbar spine: a systematic review.
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DOI：
10.1016/sasj-2008-0010-lr
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发表时间：
2008-01-01
期刊：
影响因子：
--
通讯作者：
Vaccaro, Alexander R
中科院分区：
文献类型：
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作者：
Barrey, Cedric Y;Ponnappan, Ravi K;Vaccaro, Alexander R
研究设计：本研究是对已发表的生物力学研究的系统综述，涉及椎弓根螺钉后路动态稳定装置（PDS），特别关注通过功能性脊柱单元（FSU）的运动学和载荷传递。方法：通过PubMed在线数据库进行文献检索，检索时间为1990年至2008年，使用以下关键词：“生物力学”、“腰椎动态稳定”、“Graf系统”、“Dynesys”和“后路动态植入物”。“引文仅限于描述目前可用于临床的基于椎弓根螺钉的PDS器械的生物力学的论文。描述临床经验、放射学和体内试验的研究从综述中排除。测量的参数包括运动学的FSU（活动范围（ROM），中性区（NZ），和旋转中心的位置）和负载传输通过磁盘，小平面，instrument.Results：共27个出版物被发现，有关腰椎椎弓根螺钉为基础的动态稳定仪器的生物力学评价。9项体外实验研究和4项有限元分析符合纳入标准。Dynesys植入物是研究最多的基于椎弓根螺钉的PDS系统。体外尸体研究主要集中在运动学比较ROM的完整与仪器的脊柱，而有限元分析允许分析的负荷传输在仪器和相邻level.CONCLUSION：生物力学研究表明，椎弓根螺钉为基础的PDS设备限制椎间运动，同时卸载椎间盘。植入物设计和手术技术对内固定脊柱节段的生物力学行为有显著影响。此类器械的后向放置导致非生理性椎间运动学，旋转轴向后移位。生物力学研究表明，所研究的动态器械和刚性稳定系统之间相邻节段的差异可能没有报告的那么高。最后，需要对半刚性器械进行额外研究，以进一步评价其与软稳定PDS系统相比的生物力学性能。
STUDY DESIGN: This study is a systematic review of published biomechanical studies involving pedicle screw-based posterior dynamic stabilization devices (PDS) with a special focus on kinematics and load transmission through the functional spine unit (FSU).METHODS: A literature search was performed via the PubMed online database from 1990 to 2008 using the following key words: "biomechanics," "lumbar dynamic stabilization," "Graf system," "Dynesys," and "posterior dynamic implant." Citations were limited to papers describing biomechanics of pedicle screw-based PDS devices currently available for clinical use. Studies describing clinical experience, radiology, and in vivo testing were excluded from the review. Parameters measured included kinematics of the FSU (range of motion (ROM), neutral zone (NZ), and location of the center of rotation) and load transmission through the disk, facets, and instrumentation.RESULTS: A total of 27 publications were found that concerned the biomechanical evaluation of lumbar pedicle screw-based dynamic stabilization instrumentation. Nine in vitro experimental studies and 4 finite element analyses satisfied the inclusion criteria. The Dynesys implant was the most investigated pedicle screw-based PDS system. In vitro cadaveric studies mainly focused on kinematics comparing ROM of intact versus instrumented spines whereas finite element analyses allowed analysis of load transmission at the instrumented and adjacent levels.CONCLUSION: Biomechanical studies demonstrate that pedicle screw-based PDS devices limit intervertebral motion while unloading the intervertebral disk. The implant design and the surgical technique have a significant impact on the biomechanical behavior of the instrumented spinal segment. The posterior placement of such devices results in non-physiologic intervertebral kinematics with a posterior shift of the axis of rotation. Biomechanical studies suggest that the difference at the adjacent level between investigated dynamic devices and rigid stabilization systems may not be as high as reported. Finally, additional investigations of semirigid devices are needed to further evaluate their biomechanical properties compared to soft stabilization PDS systems.