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International Journal of Bioprinting Design of SLM-Ta artificial vertebral body

The absence of horizontal orientation constraints during compression. This accelerated the buckling
caused the lattice structure to expand outward during deformation of the vertical struts, thereby reducing the
compression. The force and deformation characteristics load-bearing capacity of the AVB. Therefore, sidewall
of topological thin-walled and artificial vertebral samples curvature had different effects on the elastic modulus and
during compression are displayed in Figure 17. The yield strength of the AVB. The focus of this study was to
topological thin-walled structures of AVB-1 and AVB- regulate sidewall curvature to develop an AVB exhibiting
2 featured specific sidewall curvatures, which led to the optimal mechanical properties.
formation of plastic hinges at the center of the sidewall After implantation, the AVB was osseointegrated
under compression. The inward bending of the topological with the upper and lower cervical vertebral segments,
thin-walled structure created an interaction force with thereby performing a load-bearing function and restoring
the outwardly expanding lattice structure, as shown in intervertebral height. An AVB requires adequate yield
Figure 17. In other words, the topological thin-walled strength, and its elastic modulus should closely match that
structure restricted the inclination of the peripheral unit of human bone. This reduces the risk of stress shielding and
cells of the lattice structure, imposing horizontal constraints promotes osseointegration. The elastic modulus and yield
on the internal lattice and inhibiting its outward expansion. strength of human cortical bone range from 7.7 to 21.8
The interaction force between the topological thin-walled GPa and 103 to 222 MPa, respectively. The yield strengths
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and lattice structures in AVB-1 and AVB-2 enhanced both of AVB-1, AVB-2, and AVB-3 were within the range of
the elastic modulus and the yield strength of the AVB. An human cortical bone yield strength. This demonstrated
increase in sidewall curvature led to a higher interaction that the load-bearing capacities of AVB-1, AVB-2, and
force, thereby enhancing the load-bearing capacity of AVB-3 met the requirements for the replacement of
the AVB.
diseased vertebrae. As exhibited in Figure 8, compared
The topologically thin wall of AVB-3 consisted of to AVB-1 and AVB-3, AVB-2 exhibited the highest yield-
vertical struts with zero sidewall curvature. As depicted in strength-to-elastic-modulus ratio. This design effectively
Figure 17, the outward expansion of the lattice structures reduced the stress shielding effect while maximizing the
provided a source of perturbation for vertical strut buckling load-bearing function.

Figure 17. Schematic representation of the force and deformation characteristics of TTSs and AVBs. Abbreviations: AVB: Artificial vertebral body; TTS:
Topologically thin-walled structure.

Volume 11 Issue 4 (2025) 182 doi: 10.36922/IJB025150133