Department of Reconstructive Orthopaedics, Trauma Center Murnau, Murnau, Bavaria, Germany.
Department of Trauma Surgery, RWTH Aachen University Medical Center, Aachen, Germany.
Global Spine J. 2016 Feb;6(1):46-52. doi: 10.1055/s-0035-1555659. Epub 2015 Jun 15.
Study Design Cohort study. Objective Expandable anterolateral plates facilitate the reduction of posttraumatic deformities of thoracolumbar spine injuries and are commonly used in cases of unstable injuries or compromised bone quality. In this in vitro study, the craniocaudal yield load of the osseous fixation of an anterior angular stable plate fixation system and the effect of polymethyl methacrylate (PMMA) screw augmentation on the primary stability of the screw-bone interface during kyphosis reduction was evaluated in 12 osteoporotic human thoracolumbar vertebrae. Methods The anterolateral stabilization device used for this study is comprised of two swiveling flanges and an expandable midsection. It facilitates the controlled reduction of kyphotic deformities in situ with a geared distractor. Single flanges were attached to 12 thoracolumbar vertebrae. Six specimens were augmented with PMMA by means of cannulated bone screws. The constructs were subjected to static, displacement-controlled craniocaudal loading to failure in a servohydraulic testing machine. Results The uncemented screws cut out at a mean 393 ± 66 N, whereas the cemented screws showed significantly higher yield load of 966 ± 166 N (p < 0.02). We detected no significant correlation between bone mineral density and yield load in this setting. Conclusion Our results indicate that PMMA augmentation is an effective method to increase two- to threefold the primary stability of the screw-bone interface of an anterolateral spine stabilization system in osteoporotic bone. We recommend it in cases of severely compromised bone quality to reduce the risk of screw loosening during initial kyphosis correction and to increase long-term construct stability.
队列研究。目的：可扩展的前外侧钢板有助于外伤性脊柱损伤后畸形的复位，常用于不稳定损伤或骨质量受损的情况。在这项体外研究中，我们评估了一种前角稳定钢板固定系统的骨固定的轴向屈服载荷，以及聚甲基丙烯酸甲酯（PMMA）螺钉增强对骨质疏松性胸腰椎 12 个椎体在脊柱后凸复位过程中螺钉-骨界面初始稳定性的影响。方法：本研究使用的前外侧稳定装置由两个可旋转的法兰和一个可扩展的中段组成。它通过齿轮式牵开器方便地控制在原位矫正后凸畸形。单法兰连接到 12 个胸腰椎。6 个标本通过空心骨螺钉用 PMMA 增强。在伺服液压试验机中，对构建体进行静态、位移控制的轴向加载直至失效。结果：未固定的螺钉在平均 393±66N 时拔出，而固定的螺钉显示出明显更高的屈服载荷 966±166N（p<0.02）。在这种情况下，我们没有发现骨密度与屈服载荷之间有显著的相关性。结论：我们的结果表明，PMMA 增强是一种有效的方法，可以将前外侧脊柱稳定系统的螺钉-骨界面的初始稳定性提高两到三倍，尤其是在骨质量严重受损的情况下，以降低初始脊柱后凸矫正过程中螺钉松动的风险，并增加长期结构稳定性。
