Zhang Haiping, Hao Dingjun, Sun Honghui, He Sinmin, Wang Biao, Hu Huimin, Zhang Yongyuan
Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center Xi'an, Shaanxi, China.
Am J Transl Res. 2020 Feb 15;12(2):389-396. eCollection 2020.
This finite element (FE) study of lumbar biomechanics aims to predict how the parameters like range of motion (ROM), intervertebral disc pressure (IDP), cage stress and screw stress are affected by different direction-changeable cage positions. Firstly, the three-dimensional FE model of L3-L5 segment was developed, and the model was adjusted to adapt different direction-changeable cage positions at the L4-L5 level though transforaminal lumbar interbody fusion (TLIF) with pedicle screws. The effects of Type A (the lateral region), Type B (the lateralcentral region) and Type C (the anteriocentral region) on ROM, IDP, cage stress and screw stress were examined. The results showed that after implantation of interbody cages at different positions, the ROM at surgical level L4-L5 decreased substantially in all motion modes. The maximal stress in cage decreased with Type A, B and C in all motion modes except flexion and extension. The maximal cage stress was observed in Type A with 720.5 MPa in left rotation, in Type B with 707 MPa in flexion, in Type C with 397.3 MPa in left rotation, respectively. The maximal IDP was similar in three types, with 1.6 MPa in left lateral bending in Type A, 1.5 MPa in flexion in Type B, and 1.4 MPa in flexion in Type C. The range of screw peak stress was 16.4 to 61.1 MPa in Type A, 15.9 to 50.9 MPa in Type B, and 14.6 to 46.1 MPa Type C. In conclusion, comparing the cages with different positions, anteriocentral position cage has more advantages like lower cage stress, ODL and screw stress.
这项腰椎生物力学的有限元（FE）研究旨在预测诸如活动范围（ROM）、椎间盘压力（IDP）、椎间融合器应力和螺钉应力等参数如何受到不同方向可变的椎间融合器位置的影响。首先，建立了L3-L5节段的三维有限元模型，并通过经椎间孔腰椎椎间融合术（TLIF）和椎弓根螺钉对模型进行调整，以适应L4-L5水平不同方向可变的椎间融合器位置。研究了A型（外侧区域）、B型（外侧中央区域）和C型（前中央区域）对ROM、IDP、椎间融合器应力和螺钉应力的影响。结果表明，在不同位置植入椎间融合器后，手术节段L4-L5在所有运动模式下的ROM均显著降低。除屈伸外，在所有运动模式下，椎间融合器的最大应力随A型、B型和C型降低。分别在A型的左旋中观察到最大椎间融合器应力为720.5 MPa，在B型的屈曲中为707 MPa，在C型的左旋中为397.3 MPa。三种类型的最大IDP相似，A型在左侧弯中为1.6 MPa，B型在屈曲中为1.5 MPa，C型在屈曲中为1.4 MPa。A型螺钉峰值应力范围为16.4至61.1 MPa，B型为15.9至50.9 MPa，C型为14.6至46.1 MPa。总之，比较不同位置的椎间融合器，前中央位置的椎间融合器具有更多优势，如更低的椎间融合器应力、ODL和螺钉应力。
