3D-printed Ti6Al4V thoracic fusion cage: Biomechanical behavior and strengthening mechanism

To effectively replace diseased and damaged thoracic vertebrae, a series of three-dimensional (3D) printed titanium (Ti) alloy (Ti6Al4V) thoracic fusion cages with varying volume ratio of reinforced scaffolds are designed, and their structure-function relationships are investigated systematically. It is demonstrated that the mechanical strength of fusion cage is gradually enhanced as the scaffold volume increases, which may be attributed to its textural transformation from alpha phase to beta phase. The compressive, shear, and fatigue of fusion cages successfully attain the International Organization for Standardization (ISO 23089), when the scaffold volume ratio exceeds 15%. Furthermore, the biomechanical analyses, including stress distributions and subsidence in flexion, extension, axial rotation, and lateral bending sections of fusion cages, further shed light on their potential clinical applications. This work deeply deciphers the intrinsic connection between biomechanical property and material texture of the thoracic fusion cages, offering valuable insights into their strengthening mechanism, which providing a guidance for the precise design and quick synthesis of other 3D-printed Ti6Al4V implants.