Improved osseointegration and segmental stability of 3D-printed porous tantalum cages with micro-scale structures for spinal fusion

Abstract

Spinal fusion surgery is an effective therapy for patients with disc herniation and degenerative disc disease. In this procedure, the intervertebral cage plays a key role in reconstructing stability and achieving fusion, though its clinical efficacy is limited by inadequate osseointegration. In this study, we developed a tantalum (Ta) cage, featuring micro-scale roughness and a porous microstructure, using advanced three-dimensional (3D) printing techniques. The aim of the study was to investigate its osteogenic potential in vitro and intervertebral fusion capability in vivo. Compared with conventional polyetheretherketone cages, in vitro biological experiments demonstrated that the 3D-printed porous Ta (3D-pTa) cages significantly enhanced osteoblast adhesion, proliferation, and differentiation. In vivo spinal fusion studies in a sheep model demonstrated significant increases in bone-implant contact and bone volume to total volume ratios (p < 0.05) with the 3D-pTa cages, indicating marked bone ingrowth and effective spinal fusion. Additionally, mechanical tests revealed that the 3D-pTa cages provided consistent stability and stiffness, significantly reducing the range of motion at various time points (p < 0.05). Our findings indicate that the 3D-pTa cage effectively facilitates bone fusion and possesses reliable biosafety, highlighting its potential for future clinical application in spinal surgery.

Keywords

3D printing / Interbody fusion cage / Osseointegration / Porous Ta / Spine surgery

Funding

The work was supported by the National Natural Science Foundation of China (NSFC; No. 82130072 and No. 82302669).

Conflict of interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.