Gross Valentin, Zankovic Sergej, Rolauffs Bernd, Velten Dirk, Schmal Hagen, Seidenstuecker Michael
G.E.R.N. Tissue Replacement, Regeneration and Neogenesis, Department of Orthopedics and Trauma Surgery, Medical Center-Albert-Ludwigs-University of Freiburg, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.
Institute for Applied Biomechanics, Offenburg University, Offenburg, Germany.
Front Bioeng Biotechnol. 2024 Jul 22;12:1432587. doi: 10.3389/fbioe.2024.1432587. eCollection 2024.
Intervertebral disk degeneration is a growing problem in our society. The degeneration of the intervertebral disk leads to back pain and in some cases to a herniated disk. Advanced disk degeneration can be treated surgically with either a vertebral body fusion or a disk prosthesis. Vertebral body fusion is currently considered the gold standard of surgical therapy and is clearly superior to disk prosthesis based on the number of cases. The aim of this work was the 3D printing of Gyroid structures and the determination of their mechanical properties in a biomechanical feasibility study for possible use as an intervertebral disc prosthesis.
Creo Parametric 6.0.6.0 was used to create models with various Gyroid properties. These were printed with the Original Prusa i3 MK3s+. Different flexible filaments (TPU FlexHard and TPU FlexMed, extrudr, Lauterach, Austria) were used to investigate the effects of the filament on the printing results and mechanical properties of the models. Characterization was carried out by means of microscopy and tension/compression testing on the universal testing machine.
The 3D prints with the FlexHard and FlexMid filament went without any problems. No printing errors were detected in the microscopy. The mechanical confined compression test resulted in force-deformation curves of the individual printed models. This showed that changing the Gyroid properties (increasing the wall thickness or density of the Gyroid) leads to changes in the force-deformation curves and thus to the mechanical properties.
The flexible filaments used in this work showed good print quality after the printing parameters were adjusted. The mechanical properties of the discs were also promising. The parameters Gyroid volume, wall thickness of the Gyroid and the outer wall played a decisive role for both FlexMed and FlexHard. All in all, the Gyroid structured discs (Ø 50 mm) made of TPU represent a promising approach with regard to intervertebral disc replacement. We would like to continue to pursue this approach in the future.
椎间盘退变在当今社会是一个日益严重的问题。椎间盘退变会导致背痛，在某些情况下还会引发椎间盘突出。严重的椎间盘退变可以通过椎体融合术或椎间盘假体进行手术治疗。椎体融合术目前被认为是手术治疗的金标准，从病例数量来看明显优于椎间盘假体。本研究的目的是对类螺旋结构进行3D打印，并在生物力学可行性研究中测定其力学性能，以探讨其作为椎间盘假体的可能性。
使用Creo Parametric 6.0.6.0创建具有不同类螺旋特性的模型。这些模型使用Original Prusa i3 MK3s+进行打印。使用不同的柔性丝材（TPU FlexHard和TPU FlexMed，extrudr，奥地利劳特拉赫）来研究丝材对打印结果和模型力学性能的影响。通过显微镜观察和在万能试验机上进行拉伸/压缩测试来进行表征。
使用FlexHard和FlexMid丝材的3D打印过程顺利。显微镜观察未发现打印错误。力学受限压缩测试得到了各个打印模型的力-变形曲线。结果表明，改变类螺旋特性（增加类螺旋的壁厚或密度）会导致力-变形曲线发生变化，从而影响力学性能。
在调整打印参数后，本研究中使用的柔性丝材显示出良好的打印质量。椎间盘的力学性能也很有前景。类螺旋体积、类螺旋壁厚和外壁等参数对FlexMed和FlexHard都起着决定性作用。总体而言，由TPU制成的类螺旋结构椎间盘（直径50毫米）在椎间盘置换方面是一种很有前景的方法。我们希望在未来继续探索这种方法。
