Rebolo Pedro, Orassi Vincenzo, Areias Bruno, Checa Sara, Ramião Nilza, Correia Jaime Filipe, Rendenbach Carsten, Natal Renato, Parente Marco
INEGI - Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, Portugal.
Julius Wolff Institute, Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany.
Front Bioeng Biotechnol. 2025 Sep 1;13:1535756. doi: 10.3389/fbioe.2025.1535756. eCollection 2025.
Mandibular reconstruction following segmental resection is a challenging procedure. The implantation of scaffolds as an alternative for microsurgical free flaps appears as a promising strategy; however, there is still a lack of understanding of how such scaffolds should be designed to support bone regeneration. This study investigates the influence of scaffold design and its mechanical properties on the biomechanical conditions induced in mandibular reconstruction.
A 3D finite element model of the human mandible was developed, and a large bone defect scenario was simulated, with physiological post-operative loading and boundary conditions. The large defect was bridged with a scaffold, supported by a titanium mesh, and stabilized with a load-bearing titanium fixation plate. To study the effect of the fixation device stiffness on the induced biomechanical conditions within the scaffold pores, two different materials were tested for the fixation device, namely, a Ti-6Al-4V titanium alloy and a polylactic acid (PLA). In addition, three different strut-based scaffold architectures were investigated with different strut orientations, while keeping the same strut diameter and similar overall porosity. Two types of material distributions through the scaffold were also studied. The first type was a hydrogel-based scaffold, whereas the second type was a multimaterial type where the scaffold was divided into three equal volume parts: in the center, a hydrogel material was employed, and in the extremities, a ceramic material. These combinations of two fixation materials and three scaffold architectures with two combination materials resulted in 12 experimental groups.
No failure was predicted in the fixation devices for any of the configurations investigated. The PLA fixation device induced higher strains within the healing region than the titanium fixation device. Differences in scaffold architecture did not influence the strain levels within the healing region. Changes in the scaffold material distribution led to considerable differences in the mechanical strains within the scaffold pores. The multimaterial scaffold induced higher strains within the healing region than the only hydrogel scaffold, which might be beneficial to promote bone healing in the defect. Thus, a multimaterial scaffold seems to be able to provide a more suitable biomechanical environment to support bone regeneration, especially in large segmental defects. Future studies should focus on the mechanobiological optimization of the scaffold design and its fixation system in different clinical scenarios.
节段性切除术后的下颌骨重建是一项具有挑战性的手术。植入支架作为显微外科游离皮瓣的替代方案似乎是一种很有前景的策略；然而，对于如何设计此类支架以支持骨再生仍缺乏了解。本研究调查了支架设计及其力学性能对下颌骨重建中诱导的生物力学条件的影响。
建立了人体下颌骨的三维有限元模型，并模拟了大骨缺损情况，设定了生理术后负荷和边界条件。用支架桥接大缺损，支架由钛网支撑，并用承重钛固定板固定。为研究固定装置刚度对支架孔隙内诱导的生物力学条件的影响，对固定装置测试了两种不同材料，即Ti-6Al-4V钛合金和聚乳酸（PLA）。此外，研究了三种不同的基于支柱的支架结构，其支柱方向不同，同时保持支柱直径相同和总体孔隙率相似。还研究了两种通过支架的材料分布类型。第一种类型是基于水凝胶的支架，而第二种类型是多材料类型，其中支架被分成三个等体积部分：在中心，采用水凝胶材料，在两端，采用陶瓷材料。这两种固定材料与三种支架结构以及两种组合材料的这些组合产生了12个实验组。
在所研究的任何配置中，固定装置均未预测到失效。PLA固定装置在愈合区域内诱导的应变高于钛固定装置。支架结构的差异并未影响愈合区域内的应变水平。支架材料分布的变化导致支架孔隙内的机械应变有相当大的差异。多材料支架在愈合区域内诱导的应变高于仅水凝胶支架，这可能有利于促进缺损部位的骨愈合。因此，多材料支架似乎能够提供更合适的生物力学环境来支持骨再生，尤其是在大节段性缺损中。未来的研究应侧重于在不同临床场景中对支架设计及其固定系统进行机械生物学优化。
