Vieweg Uwe, Keck Johannes, Krüger Sven, Arabmotlagh Mohammad, Rauschmann Michael, Schilling Christoph
Krankenhaus Rummelsberg, Department of Surgical and Conservative Spine Therapy, Rummelsberg, Germany.
Aesculap AG, Research & Development, Tuttlingen, Germany.
Brain Spine. 2022 Dec 21;3:101708. doi: 10.1016/j.bas.2022.101708. eCollection 2023.
Several types of rod-to-rod connectors are available for the extension of spinal fixation systems. However, scientific literature regarding the mechanical performance of different rod-to-rod connector systems is lacking.
The goal of this study was to evaluate the mechanical characteristics of axial and lateral rod connectors in comparison to a conventional pedicle screw rod (titanium and cobalt chromium) construct.
Six types of instrumentations were investigated in a standardized test model to quantify the mechanical differences: 1: titanium rod; 2: titanium rod with axial connector; 3: titanium rod with lateral connector; 4: cobalt chromium rod; 5: cobalt chromium rod with axial connector; 6: cobalt chromium rod with lateral connector. All groups were tested in static compression, static torsion and dynamic compression and statistically compared regarding failure load and stiffness.
In static compression loading, the use of connectors increased the construct stiffness, but unaffected the yield load. The use of a cobalt chromium rod significantly increased by approximately 40% the yield load and stiffness in comparison to the titanium rod configurations. Under dynamic compression, a similar or higher fatigue strength for all tested groups in comparison to the titanium rod configuration was evaluated, with the exception of titanium rod with axial connector.
Biomechanically, using rod connectors is a secure way for the extension of a construct and is mechanically equal to a conventional screw rod construct. However, in clinical use, attention should be paid regarding placement of the connectors at high loaded areas.
有几种类型的棒对棒连接器可用于脊柱固定系统的延长。然而，关于不同棒对棒连接器系统力学性能的科学文献却很匮乏。
本研究的目的是评估轴向和横向棒连接器与传统椎弓根螺钉棒（钛和钴铬合金）结构相比的力学特性。
在一个标准化测试模型中研究了六种类型的器械装置，以量化力学差异：1：钛棒；2：带轴向连接器的钛棒；3：带横向连接器的钛棒；4：钴铬合金棒；5：带轴向连接器的钴铬合金棒；6：带横向连接器的钴铬合金棒。所有组均进行静态压缩、静态扭转和动态压缩测试，并就破坏载荷和刚度进行统计学比较。
在静态压缩加载中，使用连接器增加了结构刚度，但不影响屈服载荷。与钛棒结构相比，使用钴铬合金棒显著提高了约40%的屈服载荷和刚度。在动态压缩下，除带轴向连接器的钛棒外，所有测试组的疲劳强度与钛棒结构相比相似或更高。
从生物力学角度来看，使用棒连接器是延长结构的一种安全方法，并且在力学上等同于传统的螺钉棒结构。然而，在临床应用中，应注意连接器在高负荷区域的放置。
