Kahaer Alafate, Maimaiti Xieraili, Maitirouzi Julaiti, Wang Shuiquan, Shi Wenjie, Abuduwaili Nueraihemaiti, Zhou Zhihao, Liu Dongshan, Maimaiti Abulikemu, Rexiti Paerhati
Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China.
College of Mechanical Engineering, Xinjiang University, Urumqi, China.
Front Surg. 2022 Jul 18;9:911742. doi: 10.3389/fsurg.2022.911742. eCollection 2022.
Hybrid fixation techniques including the both modified cortical bone trajectory (MCBT) and traditional trajectory (TT) at the L4 and L5 lumbar segment are firstly proposed by our team. Therefore, the purpose of this study is to evaluate and provide specific biomechanical data of the hybrid fixation techniques including the MCBT and TT.
Four human cadaveric specimens were from the anatomy laboratory of Xinjiang Medical University. Four finite-element (FE) models of the L4-L5 lumbar spine were generated. For each of them, four implanted models with the following fixations were established: TT-TT (TT screw at the cranial and caudal level), MCBT-MCBT (MCBT screw at the cranial and caudal level), hybrid MCBT-TT (MCBT screw at the cranial level and TT screw at the caudal level), and TT-MCBT (TT screw at the cranial level and MCBT screw at the caudal level). A 400-N compressive load with 7.5 N/m moments was applied to simulate flexion, extension, lateral bending, and 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 were compared.
Compared to the TT-TT group, the MCBT-TT showed a significant lower ROM of the L4-L5 segment ( ≤ 0.009), lower ROM of the posterior fixation ( < 0.001), lower intervertebral disc stress ( < 0.001), and lower posterior fixation stress (≤ 0.041). TT-MCBT groups showed a significant lower ROM of the L4-L5 segment ( ≤ 0.012), lower ROM of the posterior fixation ( < 0.001), lower intervertebral disc stress (0.001), and lower posterior fixation stress ( ≤ 0.038).
The biomechanical properties of the hybrid MCBT-TT and TT-MCBT techniques at the L4-L5 segment are superior to that of stability MCBT-MCBT and TT-TT techniques, and feasibility needs further cadaveric study to verify.
我们团队首次提出了在L4和L5腰椎节段采用改良皮质骨轨迹（MCBT）和传统轨迹（TT）相结合的混合固定技术。因此，本研究的目的是评估并提供包括MCBT和TT在内的混合固定技术的具体生物力学数据。
4具人体尸体标本来自新疆医科大学解剖实验室。建立了4个L4-L5腰椎的有限元（FE）模型。对于每个模型，建立了4种植入模型，采用以下固定方式：TT-TT（在头侧和尾侧水平使用TT螺钉）、MCBT-MCBT（在头侧和尾侧水平使用MCBT螺钉）、混合MCBT-TT（在头侧水平使用MCBT螺钉，在尾侧水平使用TT螺钉）和TT-MCBT（在头侧水平使用TT螺钉，在尾侧水平使用MCBT螺钉）。分别施加400 N的压缩载荷和7.5 N/m的力矩来模拟前屈、后伸、侧方弯曲和旋转。比较L4-L5节段的活动范围（ROM）、后方固定情况、椎间盘的von Mises应力以及后方固定应力。
与TT-TT组相比，MCBT-TT组的L4-L5节段ROM显著降低（≤0.009），后方固定的ROM降低（<0.001），椎间盘应力降低（<0.001），后方固定应力降低（≤0.041）。TT-MCBT组的L4-L5节段ROM显著降低（≤0.012），后方固定的ROM降低（<0.001），椎间盘应力降低（0.001），后方固定应力降低（≤0.038）。
L4-L5节段混合MCBT-TT和TT-MCBT技术的生物力学性能优于稳定性MCBT-MCBT和TT-TT技术，其可行性需要进一步的尸体研究来验证。
