Faundez Antonio A, Mehbod Amir A, Wu Chunhui, Wu Wentien, Ploumis Avraam, Transfeldt Ensor E
Service de Chirurgie Orthopédique et de Traumatologie de l'Appareil Moteur, Hôpitaux Universitaires de Genève, Geneva, Switzerland.
J Spinal Disord Tech. 2008 May;21(3):175-80. doi: 10.1097/BSD.0b013e318074bb7d.
Biomechanical study.
To test 2 different intervertebral positions of a semilunar cage and their effects on 3-dimensional stability and segmental lordosis in a model of transforaminal lumbar interbody fusion (TLIF).
In his original TLIF description, Harms recommended decortication of endplates, followed by placement of mesh cages in the middle-posterior intervertebral third. Subsequent studies presented conflicting recommendations: anterior placement of the spacer-cage for better load-sharing versus placement on the stronger posterolateral endplate regions.
Six human lumbar spinal functional units were first tested intact. TLIF was performed using a semilunar poly-ether-ether-ketone cage randomly inserted in the anterior (TLIF-A) or posterior (TLIF-P) disc space. Pedicle screws and rods were added. Unconstrained pure moments in axial-torsion, lateral-bending (LB), and flexion-extension (FE) were applied under 0.05 Hz and +/-5 Nm sinusoidal waveform. Segmental motions were recorded. Range of motion (ROM) and neutral zone (NZ) were calculated. Pairwise comparisons were made using nonparametric Wilcoxon-matched pairs signed rank sum test with statistical significance set at P<0.05.
TLIF-A and TLIF-P significantly decreased ROM (P<0.05) of the intact spinal functional unit, in FE and LB. In axial-torsion, decrease of ROM after TLIF procedures was not significant (P>0.05). Delta-ROM between TLIF-A and TLIF-P was not significant (P>0.05). TLIF-A and TLIF-P significantly decreased NZ in LB (P<0.05). In FE, TLIF-P significantly decreased NZ (P<0.05); TLIF-A showed a trend toward significance (P=0.09). Delta-NZ between TLIF-A and TLIF-P was not significant (P>0.05). Segmental lordosis of TLIF-A and TLIF-P on C-arm views showed angle differences within the range of measurement error of Cobb angles.
Difference in ROM and NZ between anterior (TLIF-A) or posterior (TLIF-P) positions was not statistically significant. Similarly, both positions did not influence segmental lordosis.
生物力学研究。
在经椎间孔腰椎椎间融合术（TLIF）模型中，测试半月形椎间融合器的两种不同椎间位置及其对三维稳定性和节段性前凸的影响。
在其最初的TLIF描述中，哈姆斯建议对终板进行去皮质处理，然后在椎间后中部三分之一处放置网状融合器。随后的研究提出了相互矛盾的建议：椎间融合器向前放置以实现更好的负荷分担，与放置在更强壮的后外侧终板区域。
首先对六个完整的人体腰椎功能单位进行测试。使用随机插入前侧（TLIF-A）或后侧（TLIF-P）椎间盘间隙的半月形聚醚醚酮融合器进行TLIF手术。添加椎弓根螺钉和棒。在0.05Hz和+/-5Nm正弦波形下施加轴向扭转、侧方弯曲（LB）和屈伸（FE）方向的无约束纯力矩。记录节段运动。计算运动范围（ROM）和中性区（NZ）。使用非参数威尔科克森配对符号秩和检验进行成对比较，统计学显著性设定为P<0.05。
TLIF-A和TLIF-P在FE和LB方向上显著降低了完整腰椎功能单位的ROM（P<0.05）。在轴向扭转方向上，TLIF手术后ROM的降低不显著（P>0.05）。TLIF-A和TLIF-P之间的ROM差值不显著（P>0.05）。TLIF-A和TLIF-P在LB方向上显著降低了NZ（P<0.05）。在FE方向上，TLIF-P显著降低了NZ（P<0.05）；TLIF-A显示出显著趋势（P=0.09）。TLIF-A和TLIF-P之间的NZ差值不显著（P>0.05）。C形臂X线片上TLIF-A和TLIF-P的节段性前凸显示角度差异在Cobb角测量误差范围内。
前侧（TLIF-A）或后侧（TLIF-P）位置之间的ROM和NZ差异无统计学意义。同样，两种位置均不影响节段性前凸。
