Structural and mechanical evaluations of a topology optimized titanium interbody fusion cage fabricated by selective laser melting process

Abstract

A topology optimized lumbar interbody fusion cage was made of Ti-Al6-V4 alloy by the rapid prototyping process of selective laser melting (SLM) to reproduce designed microstructure features. Radiographic characterizations and the mechanical properties were investigated to determine how the structural characteristics of the fabricated cage were reproduced from design characteristics using micro-computed tomography scanning. The mechanical modulus of the designed cage was also measured to compare with tantalum, a widely used porous metal. The designed microstructures can be clearly seen in the micrographs of the micro-CT and scanning electron microscopy examinations, showing the SLM process can reproduce intricate microscopic features from the original designs. No imaging artifacts from micro-CT were found. The average compressive modulus of the tested caged was 2.97+/-0.90 GPa, which is comparable with the reported porous tantalum modulus of 3 GPa and falls between that of cortical bone (15 GPa) and trabecular bone (0.1-0.5 GPa). The new porous Ti-6Al-4V optimal-structure cage fabricated by SLM process gave consistent mechanical properties without artifactual distortion in the imaging modalities and thus it can be a promising alternative as a porous implant for spine fusion.

Bioactive treatment promotes osteoblast differentiation on titanium materials fabricated by selective laser melting technology

“…For this purpose, additive manufacturing methods with metal powders have been recently introduced to the field of orthopedics, and hip implants fabricated by electron beam melting are already in clinical use 2) . Selective laser melting (SLM) technology [3][4][5] is one of the additive manufacturing methods available for the formation of metal implants. In the SLM process, the small metal powder particles are melted and fused in layers by a laser.…”

X-ray computed tomography and additive manufacturing in medicine: a review

“…In the latter paper [52], the authors implanted the bone replacements into rabbit tibiae, performing XCT scans on a weekly basis to show bone ingrowth. Numerous other cases of XCT as a visual inspection tool for AM parts, post-build and postimplantation, were also published around this time; examples of which can be found elsewhere [53][54][55][56]. In the paper by Saijo et al [54], the authors presented the first human implantation of AM parts produced by binder jetting and based on patient XCT data, which achieved good biodegradability and osseoconductivity.…”

Manufacturing and Microstructure Evaluation of Ti-Ta Alloy for Biomedical Application

“…Ti alloys have been first time used in orthopaedics in the mid1940s and have continued to gain consideration due to their exceptional properties, like high specific strength, excellent resistance to corrosion, low weight and superior biocompatibility [5][6][7][8]. As for bone replacement, strength of pure Ti is not enough and Ti alloys are favoured owing to their excellent mechanical properties [9][10][11]. Various alloying elements like Ta, Zr, Mo, Nb etc.…”