Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830054, Xinjiang, China.
College of Mechanical Engineering, Xinjiang University, Urumqi 830054, Xinjiang, China.
J Healthc Eng. 2022 Mar 28;2022:4826507. doi: 10.1155/2022/4826507. eCollection 2022.
There is no detailed biomechanical research about the hybrid CBT-TT (CBT screws at cranial level and TT screws at caudal level) and TT-CBT (TT screws at cranial level and CBT screws at caudal level) techniques with finite element (FE) method. Therefore, the purpose of this study was to evaluate and provide specific biomechanical data of the hybrid lumbar posterior fixation system and compare with traditional pedicle screw and cortical screw trajectories without fusion, in FE method. Specimens were from the anatomy laboratory of Xinjiang Medical University. Four FE models of the L4-L5 lumbar spine segment were generated. For each of these, four implanted models with the following instruments were created: bilateral traditional trajectory screw fixation (TT-TT), bilateral cortical bone trajectory screw fixation (CBT-CBT), hybrid CBT-TT fixation, and hybrid TT-CBT fixation. A 400 N compressive load with 7.5 Nm moments was applied so as to simulate flexion, extension, left lateral bending, right lateral bending, left rotation, and right rotation, respectively. The range of motion (ROM) of the L4-L5 segment and the posterior fixation, the von Mises stress of the intervertebral disc, and the posterior fixation in four implanted models were compared. CBT-TT displayed a lower ROM of the fixation segment (3.82 ± 0.633°) compared to TT-TT (4.78 ± 0.306°) and CBT-CBT (4.23 ± 0.396°). In addition, CBT-TT showed a lower ROM of the posterior fixation (0.595 ± 0.108°) compared to TT-TT (0.795 ± 0.103°) and CBT-CBT (0.758 ± 0.052°). The intervertebral disc stress of CBT-TT (4.435 ± 0.604 MPa) was lower than TT-TT (7.592 ± 0.387 MPa) and CBT-CBT (6.605 ± 0.600 MPa). CBT-TT (20.228 ± 3.044 MPa) and TT-CBT (12.548 ± 2.914 MPa) displayed a lower peak von Mises stress of the posterior fixation compared to TT-TT (25.480 ± 3.737 MPa). The hybrid CBT-TT and TT-CBT techniques offered superior fixation strength compared to the CBT-CBT and TT-TT techniques.
关于混合 CBT-TT（颅侧使用 CBT 螺钉，尾侧使用 TT 螺钉）和 TT-CBT（颅侧使用 TT 螺钉，尾侧使用 CBT 螺钉）技术的详细生物力学研究尚未见报道。因此，本研究旨在通过有限元（FE）方法评估和提供混合腰椎后路固定系统的具体生物力学数据，并与传统的椎弓根螺钉和皮质骨螺钉轨迹（不融合）进行比较。标本来自新疆医科大学解剖学实验室。建立了 4 个 L4-L5 腰椎节段的 FE 模型。对于每个模型，创建了以下 4 种植入模型：双侧传统轨迹螺钉固定（TT-TT）、双侧皮质骨轨迹螺钉固定（CBT-CBT）、混合 CBT-TT 固定和混合 TT-CBT 固定。施加 400 N 的压缩载荷和 7.5 Nm 的力矩，分别模拟前屈、伸展、左侧弯、右侧弯、左旋转和右旋转。比较了 4 种植入模型的 L4-L5 节段和后路固定的活动范围（ROM）、椎间盘的 von Mises 应力和后路固定的 von Mises 应力。与 TT-TT（4.78°±0.306°）和 CBT-CBT（4.23°±0.396°）相比，CBT-TT 显示固定节段的 ROM 较低（3.82°±0.633°）。此外，与 TT-TT（0.795°±0.103°）和 CBT-CBT（0.758°±0.052°）相比，CBT-TT 显示后路固定的 ROM 较低（0.595°±0.108°）。与 TT-TT（7.592°±0.387°）和 CBT-CBT（6.605°±0.600°）相比，CBT-TT 的椎间盘应力较低（4.435°±0.604 MPa）。与 TT-TT（25.480°±0.3737 MPa）相比，CBT-TT（20.228°±3.044 MPa）和 TT-CBT（12.548°±2.914 MPa）的后路固定峰值 von Mises 应力较低。与 CBT-CBT 和 TT-TT 技术相比，混合 CBT-TT 和 TT-CBT 技术具有更好的固定强度。
