新型β钛合金椎弓根钉棒固定系统的体外力学测试与有限元分析

doi:10.12122/j.issn.1673-4254.2026.03.17

摘要/Abstract

摘要：

目的对比新型Ti-3Zr-2Sn-3Mo-25Nb β钛合金与传统Ti-6Al-4V钛合金椎弓根钉棒固定系统在后路腰椎椎体间融合术（PLIF）中的生物力学差异。方法通过体外力学测试评估β钛合金螺钉、连接棒以及二者组成的固定系统抵抗弯曲、拉伸、压缩以及扭转载荷的力学性能。构建两种PLIF有限元模型，从而比较Ti-6Al-4V与β钛合金钉棒固定系统对活动度（ROM）、终板以及植入物应力的影响。结果体外力学测试显示，β钛合金螺钉具有良好的抗弯曲（455.95±18.66 N）与扭转（9.03±0.20 N·m）性能。β钛合金棒可负载最大拉力为17647.06 ± 101.89 N。β钛合金钉棒系统负载最大压力为417.65±5.09 N、最大扭矩为25.00±0.70 N·m。与Ti-6Al-4V相比，β钛合金模型中ROM增加2.6%~8.3%，椎间植骨、椎间融合器、终板的峰值应力分别增加1.4%~8.5%、2.2%~9.4%、2.2%~10.1%，骨-螺钉界面、钉棒系统的峰值应力分别降低8.8%~23.7%、19.0%~33.1%。结论 β钛合金椎弓根固定系统具有良好的体外力学性能，它可能提供与传统Ti-6Al-4V固定系统相似的稳定性，同时明显降低钉棒系统的应力集中。新型Ti-3Zr-2Sn-3Mo-25Nb β钛合金椎弓根钉棒固定系统具有良好的应用潜力。

关键词: β钛合金, 椎弓根钉棒固定系统, 有限元分析, 后路腰椎椎体间融合术

Abstract:

Objective To compare the biomechanical properties of a novel Ti-3Zr-2Sn-3Mo-25Nb β‑titanium alloy and a traditional Ti-6Al-4V titanium alloy pedicle screw-rod fixation system in posterior lumbar interbody fusion (PLIF). Methods In vitro mechanical tests were conducted to evaluate the bending, tensile, compressive, and torsional performance of the β-titanium alloy screws, connecting rods, and the assembled screw-rod fixation system. Two PLIF finite element models were constructed to compare the effects of Ti-6Al-4V versus β-titanium screw-rod systems on range of motion (ROM) and stresses in the endplate and implants. Results In vitro tests showed that the β‑titanium alloy screw exhibited good resistance to bending (455.95±18.66 N) and torsion (9.03±0.20 N·m). The maximum tensile load of the β-titanium rod was 17 647.06±101.89 N, and the β-titanium screw‑rod system showed a maximum compressive load of 417.65±5.09 N and a maximum torque of 25.00±0.70 N·m. Compared with Ti-6Al-4V, the β‑titanium model showed a 2.6%-8.3% increase in ROM, and the peak stresses in the interbody bone graft, cage, and endplate increased by 1.4%-8.5%, 2.2%-9.4%, and 2.2%-10.1%, respectively, whereas the peak stresses at the bone-screw interface and within the screw-rod system decreased by 8.8%-23.7% and 19.0%-33.1%, respectively. Conclusion The β‑titanium pedicle screw-rod fixation system exhibits good in vitro mechanical performance to provide stability comparable to the conventional Ti-6Al-4V system while markedly reducing stress concentration within the screw-rod construct, suggesting its great potential for clinical application.

Key words: β-titanium alloy, pedicle screw-rod fixation system, finite element analysis, posterior lumbar interbody fusion

李杰, 刘毅楠, 王栋, 李浩鹏, 贺西京, 卢腾. 新型β钛合金椎弓根钉棒固定系统的体外力学测试与有限元分析[J]. 南方医科大学学报, 2026, 46(3): 638-645.

Jie LI, Yinan LIU, Dong WANG, Haopeng LI, Xijing HE, Teng LU. In vitro mechanical testing and finite element analysis of a novel β-Titanium alloy pedicle screw-rod fixation system[J]. Journal of Southern Medical University, 2026, 46(3): 638-645.

图/表 8

图1 β钛合金螺钉及固定棒成品

Fig.1 Finished β-Titanium alloy screws and the connecting rods.

图2 β钛合金钉棒静态力学性能测试过程

Fig.2 Static mechanical testing of β-titanium alloy screws and rods. A: Tensile test of the β-titanium alloy rod. B: Compression-torsion test of the β-titanium alloy screw-rod system. C: Torsion test of the β-titanium alloy screw. D: Bending test of the β-titanium alloy screw.

图3 完整L4-L5腰椎有限元模型

Fig.3 Intact L4-L5 lumbar finite element model. A: Lateral view. B: Posterior view. C: Axial view.

表1 有限元模型中的材料属性与单元类型

Tab.1 Material properties and element types in the finite element models

Materials	Element type	Constitutive equation	Young's modulus	Poisson's ratio (μ)
Cortical bone	C3D4	Isotropic elastic	12 GPa	0.3
Cancellous bone	C3D4	neo-Hookean	C₁₀ = 19.38 MPa, D = 0.0252 MPa
Bony endplate	C3D8I	Isotropic elastic	1.2 GPa	0.29
Cartilage endplate	C3D8I	neo-Hookean	C₁₀ = 4.10 MPa, D =0.03 MPa
Nucleus pulposus	C3D8H	Mooney-Rivlin	C₁₀ = 0.12 MPa, C₀₁ = 0.03 MPa
Annulus ground	C3D8H	Mooney-Rivlin	C₁₀ = 0.18 MPa, C₀₁ = 0.045 MPa
Annulus fiber	T3D2	Hypoelastic	360-550 MPa
Screws and rods	C3D4	Isotropic elastic	110 GPa, 55 GPa	0.3
Cage	C3D4	Isotropic elastic	3.6 GPa	0.25
Bone grafts	C3D4	Isotropic elastic	100 MPa	0.2

图4 后路腰椎椎体间融合术(PLIF)模型

Fig.4 Posterior lumbar interbody fusion (PLIF) model. A: Lateral view. B: Posterior view. C: Axial view.

图5 β钛合金椎弓根钉棒固定系统的体外力学性能测试

Fig.5 Results of in vitro mechanical testing of the β-titanium alloy pedicle screw-rod fixation system. A: Torsion test of the β‑titanium alloy screw. B: Bending test of the β‑titanium alloy screw. C: Tensile test of the β‑titanium alloy rod. D: Compression test of the β-titanium alloy screw-rod fixation system. E: Torsion test of the β‑titanium alloy screw-rod fixation system.

图6 节段活动度与组件应力分析结果

Fig.6 Results of segmental range of motion and stress within components. A: Segment range of motion for each model. B: Peak stress in the interbody bone graft. C: Peak stress in the cage. D: Peak stress in the endplate. E: Peak stress at the bone-screw interface. F: Peak stress in the screw-rod system.

图7 终板、植骨、cage以及钉棒系统的应力云图

Fig.7 Stress nephogram of the endplate, interbody bone graft, cage, and screw-rod system.

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