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Updated: Mar 28, 2026
An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model
Published on: May 31, 2017
[In vitro mechanical testing and finite element analysis of a novel β-Titanium alloy pedicle screw-rod fixation
Objectives:
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.
Conclusions:
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.
