Department of Oral and Maxillofacial Surgery, University Hospital of Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, 24105 Kiel, Germany.
Syntellix AG, Aegidientorplatz 2a, 30159 Hanover, Germany.
Acta Biomater. 2017 Oct 15;62:434-445. doi: 10.1016/j.actbio.2017.08.031. Epub 2017 Aug 24.
Biodegradable magnesium alloys are a new class of implant material suitable for bone surgery. The aim of this study was to investigate plates and screws made of magnesium for osteosynthesis in comparison to titanium in a cranial fracture model. Implants were used for internal fixation of a cranio-osteoplasty in nine minipigs. Computed tomography was conducted repeatedly after surgery. The implants and the adjacent tissues were harvested 10, 20 and 30weeks after surgery and investigated by micro-computed tomography and histological analysis. The surgical procedure and the inserted osteosynthesis material were well tolerated by the animals, and the bone healing of the osteoplasty was undisturbed at all times. The adjacent bone showed formation of lacunas in the magnesium group, resulting in a lower bone-to-implant contact ratio than that of titanium (72 vs. 94% at week 30), but this did not lead to clinical side effects. Radiological measurements showed no reduction in osteosynthesis material volume, but indicated signs of degradation: distinct volumes within the magnesium osteosynthesis group had lower density in micro-computed tomography, and these volumes increased up to 9% at week 30. The histological preparations showed areas of translucency and porosity inside the magnesium, but the outer shape of the osteosynthesis material remained unchanged. No fracture or loosening of the osteosynthesis devices appeared. Soft tissue probes confirmed sufficient biocompatibility. Given their biodegradable capacity, biocompatibility, mechanical strength and visibility on radiographs, osteosynthesis plates made of magnesium alloys are suitable for internal fixation procedures.
To the best of our knowledge this is the first study that used biodegradable magnesium implants for osteosynthesis in a cranial fracture model. The cranio-osteoplasty in miniature pigs allowed in vivo application of plate and screw osteosynthesis of standard-sized implants and the implementation of surgical procedures similar to those conducted on human beings. The osteosynthesis configuration, size, and mechanical properties of the magnesium implants within this study were comparable to those of titanium-based osteosynthesis materials. The results clearly show that bone healing was undisturbed in all cases and that the biocompatibility to hard- and soft tissue was sufficient. Magnesium implants might help to avoid long-term complications and secondary removal procedures due to their biodegradable properties.
可生物降解的镁合金是一类适合骨外科的新型植入材料。本研究的目的是在颅骨骨折模型中比较镁制板和螺钉与钛制板和螺钉的骨结合情况。将植入物用于 9 头小型猪的颅成形术内固定。术后反复进行计算机断层扫描。术后 10、20 和 30 周分别取出植入物和相邻组织，进行微计算机断层扫描和组织学分析。手术过程和插入的骨结合材料被动物很好地耐受，骨成形术的骨愈合始终未受干扰。在镁组中，相邻骨形成了腔隙，导致骨-植入物接触率低于钛（第 30 周时为 72%比 94%），但这并未导致临床副作用。影像学测量显示骨结合材料体积无减少，但有降解迹象：在镁骨结合组中，明显的体积在微计算机断层扫描中密度较低，这些体积在第 30 周时增加了 9%。组织学准备显示镁内有半透明和多孔区域，但骨结合材料的外形成形保持不变。没有出现骨结合装置的断裂或松动。软组织探针证实具有足够的生物相容性。鉴于其可生物降解能力、生物相容性、机械强度和 X 射线照相中的可视性，镁合金骨结合板适用于内固定程序。
据我们所知，这是第一项使用可生物降解镁植入物进行颅骨骨折模型骨结合的研究。小型猪的颅成形术允许体内应用标准尺寸植入物的板和螺钉骨结合，并实施类似于对人类进行的手术程序。本研究中镁植入物的骨结合结构、尺寸和机械性能与基于钛的骨结合材料相当。结果清楚地表明，在所有情况下骨愈合均未受到干扰，并且对硬组织和软组织的生物相容性足够。由于镁植入物具有可生物降解的特性，因此可能有助于避免长期并发症和继发性去除程序。
