Biomechanical comparison of single-level posterior versus transforaminal lumbar interbody fusions with bilateral pedicle screw fixation: segmental stability and the effects on adjacent motion segments Laboratory investigation
Biomechanical comparison of single-level posterior versus transforaminal lumbar interbody fusions with bilateral pedicle screw fixation: segmental stability and the effects on adjacent motion segments Laboratory investigation
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DOI：
10.3171/2009.12.spine09123
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发表时间：
2010-06-01
影响因子：
2.8
通讯作者：
Park, Jon
中科院分区：
文献类型：
--
作者：
Sim, Hong Bo;Murovic, Judith A.;Park, Jon
Object.后路腰椎椎间融合术（PLIF）和经椎间孔腰椎椎间融合术（TLIF）常用于腰椎关节融合术。这些手术使用不同的入路和融合器设计，即使在添加后路椎弓根螺钉固定后，每种入路和融合器设计都可能影响脊柱稳定性。本生物力学研究的目的是比较PLIF和TLIF，每种都伴随双侧椎弓根螺钉固定，关于融合节段和相邻节段的稳定性。使用载荷控制方案（LCP）对14个L2-S2人体尸体脊柱样本进行了6种不同运动模式的测试：屈曲、伸展、左右侧弯以及左右轴向旋转。每种运动模式的LCP均以0.5 Nm/s的速率使用高达8.0 Nm的力矩，并施加400 N的恒定压缩从动件预载荷。所有14个样本均在完整状态下进行测试。然后将标本平均分为PLIF和TLIF条件。在PLIF组中，先进行双侧L4-5部分关节突切除术，然后进行椎间盘切除术和单节段融合术。在TLIF组中，进行了单侧L4-5完全关节面切除术（随后进行了椎间盘切除术和单节段融合术）。在TLIF组中，最初将植入物向后定位在椎间隙内（TLIF-P），并对样本进行测试;然后将植入物向前定位（TLIF-A），并对样本进行重新测试。评估所有标本重建节段和邻近节段的活动范围（ROM）以及邻近节段的椎间盘内压力（IDP）和椎板应变。结果。在重建节段，PLIF和TLIF标本的ROM均显著低于完整状态的ROM（p < 0.05）。对于侧弯，PLIF导致ROM显著降低，在统计学上显著大于TLIF后的结果（p < 0.05）。在屈伸和旋转方面，PLIF组的ROM也较小，但是，与侧弯ROM的差异不同，这些ROM值的差异不具有统计学意义。椎间隙内植入物位置的变化与ROM值的任何显著差异无关（p = 0.43）。相邻节段L2-3、L3-4和L5-S1的ROM分析显示，所有方向的ROM均在一定程度上增加。与完整样本相比，屈曲-伸展载荷下所有相邻节段的ROM均增加至统计学显著程度（p < 0.05）;然而，不同手术程序之间的数值差异无统计学显著性。相邻L3-4和L5-S1节段的IDP和小关节接触力也增加，但这些值与完整脊柱相比无统计学显著性增加（p > 0.05）。关于稳定性，PLIF提供了比TLIF更高的即刻稳定性，尤其是在侧弯时。然而，根据我们的研究结果，PLIF和TLIF（均采用后外侧融合）在ROM、IDP和相邻节段的层流应变方面具有相似的生物力学特性。(DOI：10.3171/2009.12.SPINE09123）
Object. Both posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) have been frequently undertaken for lumbar arthrodesis. These procedures use different approaches and cage designs, each of which could affect spine stability, even after the addition of posterior pedicle screw fixation. The objectives of this biomechanical study were to compare PLIF and TLIF, each accompanied by bilateral pedicle screw fixation, with regard to the stability of the fused and adjacent segments.Methods. Fourteen human L2-S2 cadaveric spine specimens were tested for 6 different modes of motion: flexion, extension, right and left lateral bending, and right and left axial rotation using a load control protocol (LCP). The LCP for each mode of motion utilized moments up to 8.0 Nm at a rate of 0.5 Nm/second with the application of a constant compression follower preload of 400 N. All 14 specimens were tested in the intact state. The specimens were then divided equally into PLIF and TLIF conditions. In the PLIF Group, a bilateral L4-5 partial facetectomy was followed by discectomy and a single-level fusion procedure. In the TLIF Group, a unilateral L4-5 complete facetectomy was performed (and followed by the discectomy and single-level fusion procedure). In the TLIF Group, the implants were initially positioned inside the disc space posteriorly (TLIF-P) and the specimens were tested; the implants were then positioned anteriorly (TLIF-A) and the specimens were retested. All specimens were evaluated at the reconstructed and adjacent segments for range of motion (ROM) and at the adjacent segments for intradiscal pressure (IDP), and laminar strain.Results. At the reconstructed segment, both the PLIF and the TLIF specimens had significantly lower ROMs compared with those for the intact state (p < 0.05). For lateral bending, the PLIF resulted in a marked decrease in ROM that was statistically significantly greater than that found after TLIF (p < 0.05). In flexion-extension and rotation, the PLIF Group also had less ROM, however, unlike the difference in lateral bending ROM, these differences in ROM values were not statistically significant. Variations in the position of the implants within the disc space were not associated with any significant differences in ROM values (p = 0.43). Analyses of ROM at the adjacent levels L2-3, L3-4, and L5-S1 showed that ROM was increased to some degree in all directions. When compared with that of intact specimens, the ROMs were increased to a statistically significant degree at all adjacent segments in flexion-extension loads (p < 0.05); however, the differences in values among the various operative procedures were not statistically significant. The IDP and facet contact force for the adjacent L3-4 and L5-S1 levels were also increased, but these values were not statistically significantly increased from those for the intact spine (p > 0.05).Conclusions. Regarding stability, PLIF provides a higher immediate stability compared with that of TLIF, especially in lateral bending. Based on our findings, however, PLIF and TLIF, each with posterolateral fusions, have similar biomechanical properties regarding ROM. IDP, and laminar strain at the adjacent segments. (DOI: 10.3171/2009.12.SPINE09123)