Radiologischer und histomorphometrischer Vergleich von Degradationsverhalten und Osseointegration PEO-oberflächenmodifizierter und nichtoberflächenmodifizierter ZX00-basierter Magnesiumimplantate

Beschreibung

Radiological and histomorphometric comparison of degradation behavior and osseointegration of PEO-surface-modified and non-surface-modified ZX00-based magnesium implants: An in vivo study after 6,12 and 18 months in the Minipig In the past the surgical treatment of fractures with resorbable magnesium-based osteosynthesis materials has been shown to be advantageous over non-resorbable osteosynthesis materials such as titanium or resorbable polymer-based osteosynthesis materials for some indications. The limitation for routine use is the hydrogen gas released during degradation, which led to subcutaneous and intraosseous gas accumulation around the implant in previous studies. To ensure stable bone-implant contact during fracture healing and to avoid adverse effects in the bone around the implant during the degradation process, alloying and coating of magnesium-based implants was used to try to slow down degradation. The aim of this doctoral thesis was thus to investigate the degradation behavior as well as the reaction of the surrounding bone to ZX00 implants with and without PEO surface modification in a large animal experiment after 6, 12 and 18 months of implantation. For this purpose, the implants were placed in the frontal bone of minipigs and analyzed radiologically and histomorphometrically after the respective standing time. The implants were explanted with the surrounding bone. The residual volume was calculated in the micro-CT examination based on the density of the material (SV/TV). In the histomorphometric examination, the proportion of the remaining implant material was calculated using the area of the implant’s cross-section (SA/TA). The results of the radiological and the histomorphometric evaluation show a higher residual volume of PEO surface-coated implants at all time points and prove the successful delay of magnesium corrosion. Significant differences were seen in the radiological evaluation after 12 and 18 months of implantation (p < 0.001), and in the histomorphometric examination after 12 months (p < 0.001). Comparison of residual volume (SV/TV) showed a significant (p < 0.001) lower value after 18 months than after 6 months for the uncoated implants. For the coated implants, due to the slowed degradation, the difference was not significant (p = 0.25). The slowed degradation of the PEO surface coating and the resulting slower release of gas should reduce the formation of gas-associated lacunae and improves osseointegration. Radiologically and histomorphometrically, two areas each from the original implant margin up to 0.5 mm and up to 1.5 mm were examined for the proportion of mineralized bone within the evaluation areas (BV/TV in the radiological, BA/TA in the histomorphometric examination). The radiological results showed a significantly higher BV/TV (p < 0.001) in both areas after 18 months of implantation time in the PEO-coated implants. Histomorphometrically, the same trends emerged. Comparison of the volume fraction of mineralized bone (BV/TV) around the implants after 6 and 18 months showed the same trends in both study areas. Between the original implant border and the 0.5 mm surrounding area, there is a significantly higher mineralized bone proportion (p = 0.035) after 18 months for the coated implant. In contrast, the BV/TV proportion decreases significantly in the uncoated implants in the study area up to 1.5 mm from the original implant boundary during the same study period (p = 0.034). Why the difference in bone volume density occurs only at the last examination time remains unclear. Based on the results of this study, it is suggested that the PEO surface coating may improve osseointegration by reducing the formation of gas-associated lacunae in the study period up to 18 months post-implantation.

Autor*in

Christoph Joachim Leber

Themen in »Radiologischer und histomorphometrischer Vergleich von Degradationsverhalten und Osseointegration PEO-oberflächenmodifizierter und nichtoberflächenmodifizierter ZX00-basierter Magnesiumimplantate«

experimental surgery Transplantate Knochen grafts fractures bones experimentelle Chirurgie chirurgische Geräte Frakturen miniature pigs Minipig surgical equipment grafting Magnesium

Stimmen zu »Radiologischer und histomorphometrischer Vergleich von Degradationsverhalten und Osseointegration PEO-oberflächenmodifizierter und nichtoberflächenmodifizierter ZX00-basierter Magnesiumimplantate«

Details

Link teilen