Escuela Técnica Superior de Ingeniería, Universidad de Sevilla, Avenida Camino de los Descubrimientos s/n, 41092, Seville, Spain.
Instituto de Biomedicina de Sevilla (IBiS), Universidad de Sevilla, Seville, Spain.
Tissue Eng Regen Med. 2023 Oct;20(6):893-904. doi: 10.1007/s13770-023-00577-2. Epub 2023 Aug 22.
3D-printed bioceramic scaffolds have gained popularity due to their controlled microarchitecture and their proven biocompatibility. However, their high brittleness makes their surgical implementation complex for weight-bearing bone treatments. Thus, they would require difficult-to-instrument rigid internal fixations that limit a rigorous evaluation of the regeneration progress through the analysis of mechanic-structural parameters.
We investigated the compatibility of flexible fixations with fragile ceramic implants, and if mechanical monitoring techniques are applicable to bone tissue engineering applications. Tissue engineering experiments were performed on 8 ovine metatarsi. A 15 mm bone segment was directly replaced with a hydroxyapatite scaffold and stabilized by an instrumented Ilizarov-type external fixator. Several in vivo monitoring techniques were employed to assess the mechanical and structural progress of the tissue.
The applied surgical protocol succeeded in combining external fixators and subject-specific bioceramic scaffolds without causing fatal fractures of the implant due to stress concentrator. The bearing capacity of the treated limb was initially altered, quantifying a 28-56% reduction of the ground reaction force, which gradually normalized during the consolidation phase. A faster recovery was reported in the bearing capacity, stiffening and bone mineral density of the callus. It acquired a predominant mechanical role over the fixator in the distribution of internal forces after one post-surgical month.
The bioceramic scaffold significantly accelerated in vivo the bone formation compared to other traditional alternatives in the literature (e.g., distraction osteogenesis). In addition, the implemented assessment techniques allowed an accurate quantitative evaluation of the bone regeneration through mechanical and imaging parameters.
3D 打印的生物陶瓷支架由于其可控的微观结构和已证明的生物相容性而受到关注。然而，它们的高脆性使得它们在承重骨治疗中的手术实施变得复杂。因此，它们需要难以操作的刚性内部固定物，这限制了通过分析力学-结构参数对再生进展的严格评估。
我们研究了柔性固定物与易碎陶瓷植入物的兼容性，以及力学监测技术是否适用于骨组织工程应用。在 8 只绵羊跗骨上进行了组织工程实验。通过仪器化的伊利扎洛夫型外固定器直接用羟基磷灰石支架替换 15 毫米的骨段并稳定。采用多种体内监测技术来评估组织的力学和结构进展。
应用的手术方案成功地将外固定器与特定于患者的生物陶瓷支架结合使用，而不会因应力集中器导致植入物发生致命骨折。受治疗肢体的承载能力最初发生改变，地面反作用力减少 28-56%，在巩固阶段逐渐恢复正常。在承载能力、刚度和骨矿物质密度方面，骨痂的恢复速度更快。在手术后一个月，它在内部力的分布中开始发挥主要的机械作用，取代了固定器。
与文献中其他传统替代物（例如，牵张成骨）相比，生物陶瓷支架显著加速了体内的骨形成。此外，实施的评估技术允许通过力学和成像参数对骨再生进行准确的定量评估。
