Ulutaş Murat, Özkaya Mustafa, Yaman Onur, Demir Teyfik
1 Department of Neurosurgery, Sanko University, Gaziantep, Turkey.
2 Mechanical Engineering Department, KTO Karatay University, Konya, Turkey.
Proc Inst Mech Eng H. 2018 Jul;232(7):655-664. doi: 10.1177/0954411918783779. Epub 2018 Jun 20.
Transforaminal lumbar interbody fusion was an alternative to posterior lumbar interbody fusion for decompression surgeries. This study investigates the biomechanical responses of the unilateral and bilateral pedicle screw fixations with/without transforaminal lumbar interbody fusion cages under axial compression, flexion, and torsional loads. Ovine vertebrae were used in this study. Cadavers, randomly divided into five, were intact control group, bilateral pedicle screw fixation group, bilateral pedicle screw fixation group with transforaminal lumbar interbody fusion cage, unilateral pedicle screw fixation group, and unilateral pedicle screw fixation group with transforaminal lumbar interbody fusion cage. Axial compression, flexion, and torsion tests were performed on specimens. All study groups provided higher stiffness and yield load values than control group under axial compression. Addition of transforaminal lumbar interbody fusion cage to bilateral fixation increased the stiffness under axial compression. Moreover, additional use of transforaminal lumbar interbody fusion in unilateral fixation increased the yield load values under axial compression. Control group was the stiffest in flexion test. Placing a transforaminal lumbar interbody fusion cage to both unilateral and bilateral fixations did not significantly change the stiffness values. Additional transforaminal lumbar interbody fusion cage increased the yield moment of the bilateral fixation. In torsion test, control group had the highest stiffness and yield torque. The facet joints are the most important parts of the vertebrae on the stability. When comparing the bilateral and unilateral fixations with transforaminal lumbar interbody fusion addition, the more facet preserving approach has significantly higher stability under axial compression, flexion, and torsion. Unilateral fixation with transforaminal lumbar interbody fusion cage can be said biomechanically stable and advantageous fixation system because of the advantage on the less facet and soft tissue resection compared to bilateral fixation with transforaminal lumbar interbody fusion.
经椎间孔腰椎椎间融合术是后路腰椎椎间融合术用于减压手术的一种替代方法。本研究调查了在轴向压缩、屈曲和扭转负荷下，有无经椎间孔腰椎椎间融合器的单侧和双侧椎弓根螺钉固定的生物力学反应。本研究使用了羊的椎体。尸体被随机分为五组，分别是完整对照组、双侧椎弓根螺钉固定组、带经椎间孔腰椎椎间融合器的双侧椎弓根螺钉固定组、单侧椎弓根螺钉固定组和带经椎间孔腰椎椎间融合器的单侧椎弓根螺钉固定组。对标本进行了轴向压缩、屈曲和扭转试验。在轴向压缩下，所有研究组的刚度和屈服负荷值均高于对照组。双侧固定中增加经椎间孔腰椎椎间融合器可提高轴向压缩下的刚度。此外，单侧固定中额外使用经椎间孔腰椎椎间融合术可提高轴向压缩下的屈服负荷值。对照组在屈曲试验中最僵硬。在单侧和双侧固定中放置经椎间孔腰椎椎间融合器均未显著改变刚度值。额外的经椎间孔腰椎椎间融合器增加了双侧固定的屈服力矩。在扭转试验中，对照组的刚度和屈服扭矩最高。小关节是椎体稳定性的最重要部分。在比较添加经椎间孔腰椎椎间融合术的双侧和单侧固定时，保留更多小关节的方法在轴向压缩、屈曲和扭转下具有明显更高的稳定性。与带经椎间孔腰椎椎间融合术的双侧固定相比，带经椎间孔腰椎椎间融合器的单侧固定在小关节和软组织切除较少方面具有优势，因此可以说是一种生物力学稳定且有利的固定系统。
