Division of Research, Logan University, 1851 Schoettler Rd, Chesterfield, MO 63017, USA.
Spine J. 2011 Apr;11(4):324-30. doi: 10.1016/j.spinee.2011.02.008.
Multilevel corpectomy, with or without anterior instrumentation, has been associated with both graft and anterior screw-plate complications. The addition of posterior instrumentation after anterior fixation has been shown to increase the overall stiffness of fused segments and decrease the likelihood of instrumentation failure. Little biomechanical information exists for providing guidance in the selection of an appropriate instrumentation technique after a multilevel cervical corpectomy. Clinical studies have also been inconclusive in choosing an optimum fixation strategy.
To test the hypothesis that combined anterior-posterior fixation would lower the stresses on the bone-screw interfaces observed after an isolated anterior fixation and on the graft-end plate interfaces observed after an isolated posterior fixation.
A finite element (FE) analysis of a C4-C7 corpectomy fusion with three different fixation techniques: anterior, posterior, and combined anterior-posterior.
A previously validated three-dimensional FE model of an intact C3-T1 segment was used. From this intact model, three additional instrumentation models were constructed using anterior (rigid screw-plate), posterior (rigid screw-rod), and combined anterior-posterior fixation techniques following a C4-C7 corpectomy fusion. Construct stability at the cephalad and caudal levels of the corpectomy was assessed.
Biomechanical comparisons between these instrumentation techniques show the least amount of construct motion in the combined anterior-posterior instrumentation model. The use of both anterior and posterior fixation shields the graft-end plate and screw-bone interfaces from peak stresses as compared with an isolated anterior or an isolated posterior fixation, thereby supporting the hypothesis of this study.
A combined fixation technique should be balanced against increased operating room time and surgery costs because of dual anterior and posterior fixation and the increased risk of long anterior plating, such as dysphasia, plate or screw dislodgement, or migration. Our study suggests that the use of posterior fixation, whether alone or in combination with anterior fixation, infers comparable stability. Further studies are warranted to identify whether the current findings are consistent with other biomechanical studies.
多节段颈椎椎体切除术（伴或不伴前路内固定）与移植物和前路螺钉-钢板并发症有关。在前路固定后增加后路内固定已被证明可以增加融合节段的整体刚度，并降低器械失效的可能性。关于选择多节段颈椎椎体切除术后路内固定技术，目前几乎没有生物力学信息可提供指导。临床研究在选择最佳固定策略方面也尚无定论。
验证假设，即联合前路-后路固定可降低单纯前路固定后观察到的骨-螺钉界面以及单纯后路固定后观察到的移植物-终板界面的应力。
对 C4-C7 椎体切除术融合的三种不同固定技术（前路、后路和联合前路-后路）进行有限元（FE）分析。
使用之前验证的完整 C3-T1 节段的三维 FE 模型。从这个完整的模型中，构建了另外三个器械模型，分别采用前路（刚性螺钉-钢板）、后路（刚性螺钉-棒）和前路-后路联合固定技术，用于 C4-C7 椎体切除术融合。评估了颈椎切除术后颅侧和尾侧节段的器械稳定性。
与单纯前路或单纯后路固定相比，这些器械技术之间的生物力学比较显示，联合前路-后路器械模型的器械运动最少。与单纯前路或单纯后路固定相比，使用前路和后路固定均可使移植物-终板和螺钉-骨界面免受峰值应力，从而支持本研究的假设。
由于双前路和后路固定以及长前路板的风险增加（如吞咽困难、板或螺钉移位或迁移），联合固定技术的应用应权衡增加的手术室时间和手术成本。我们的研究表明，后路固定（单独使用或与前路固定联合使用）可提供相当的稳定性。需要进一步的研究来确定当前的发现是否与其他生物力学研究一致。
