Department of Orthopaedics, The First Affiliated Hospital of Dalian Medical University, Dalian, China.
Department of Orthopedics, The Second Xiangya Hospital of Central South University, Changsha, China.
Orthop Surg. 2023 Apr;15(4):1153-1164. doi: 10.1111/os.13671. Epub 2023 Mar 1.
OBJECTIVES: At present, a variety of posterior lumbar internal fixation implantation methods have been developed, which makes it difficult for spine surgeons to choose. The stress distribution of the internal fixation system is one of the important indexes to evaluate these technologies. Common insertion technologies include Roy Camille, Magerl, Krag, AO, and Weinstein insertion techniques. This study aimed to compare the distribution of von Mises stresses in different screw fixation systems established by these insertion technologies. METHODS: Here, the three-dimensional finite element (FE) method was selected to evaluate the postoperative stress distribution of internal fixation. Following different pedicle screw insertion techniques, five single-segment transforaminal lumbar interbody fusion (TLIF) models were established after modeling and validation of the L1-S1 vertebrae FE model. RESULTS: By analyzing the data, we found that stress concentration phenomenon was in all the models. Additionally, Roy-Camille, Krag, AO, and Weinstein insertion techniques led to the great stress on lumbar vertebra, intervertebral disc, and screw-rod fixation systems. Therefore, we hope that the results can provide ideas for clinical work and development of pedicle screws in the future. It is worth noting that flexion, unaffected side lateral bending, and affected side axial rotation should be limited for the patients with cages implanted. CONCLUSIONS: Overall, our method obtained the results that Magerl insertion technique was the relatively safe approach for pedicle screw implantation due to its relatively dispersive stress in TLIF models.
目的:目前已经开发出多种后路腰椎内固定植入方法,这使得脊柱外科医生难以选择。内固定系统的应力分布是评估这些技术的重要指标之一。常见的植入技术包括 Roy Camille、Magerl、Krag、AO 和 Weinstein 植入技术。本研究旨在比较这些植入技术建立的不同螺钉固定系统的 von Mises 应力分布。
方法:本研究选择三维有限元(FE)方法来评估内固定术后的应力分布。在对 L1-S1 椎体 FE 模型进行建模和验证后,根据不同的椎弓根螺钉植入技术,建立了五个单节段经椎间孔腰椎体间融合(TLIF)模型。
结果:通过分析数据,我们发现所有模型都存在应力集中现象。此外,Roy-Camille、Krag、AO 和 Weinstein 植入技术导致腰椎、椎间盘和螺钉-棒固定系统承受较大的应力。因此,我们希望这些结果能为临床工作和未来椎弓根螺钉的发展提供思路。值得注意的是,对于植入 cage 的患者,应限制屈伸、未受影响侧侧屈和受影响侧轴向旋转。
结论:总之,我们的方法得出的结果是,由于 Magerl 植入技术在 TLIF 模型中应力分布相对分散,因此是相对安全的椎弓根螺钉植入方法。
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