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Orthotopic Transfer of Prefabricated Bone Flaps in a Rabbit Model
| Third-party funded project |
| Project title |
Orthotopic Transfer of Prefabricated Bone Flaps in a Rabbit Model |
| Principal Investigator(s) |
Schaefer, Dirk Johannes
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| Organisation / Research unit |
Bereich Operative Fächer (Klinik) / Plastische, rekonstruktive, ästhetische und Handchirurgie (Schaefer) |
| Project start |
01.01.2010 |
| Probable end |
31.12.2013 |
| Status |
Completed |
| Abstract |
Segmental bone defects caused by tumor excision, trauma or infection usually show a low healing potential due to infections, poor vascularisation and/or lack of bone to bone contact. Possible treatment is the transfer of non-vascularised bone or bone substitutes. Nevertheless, the current gold standard of treatment is the transfer of vascularised bone, harvested from e.g. fibula, pelvis, femoral condyle or radius. Our project aims on the creation of an artificial vascularised bone flap by tissue engineering to avoid functional and/or aesthetic donor site morbidity. Previous studies showed that Bone Marrow Stromal Cells (BMSC) seeded onto a scaffold will produce bone when placed ectopically in a, vascularised muscle flap, while those under non-vascularised conditions didn?t. Questions were raised on the benefit of orthotopic implantation and implantation strategy. We aim to test the hypothesis that an orthotopic implantation leads to quicker and increased bone formation due to load and natural microenvironment than ectopically.
Methods:
In this study, rabbit BMSC have been harvested, expanded and seeded on a construct and fixed with fibrin glue. Three groups of critical size humeral defects in rabbits have been treated with a) an orthotopic implantation of a 6 week ectopically, in a muscular flap prevascularised, cell-seeded construct, b) an orthotopically implanted non-prevascularized cell-seeded construct, wrapped in a muscule flap, and c) a cell-seeded construct without a flap. Measurements for bone formation quantity, quality and time period are carried out with periodic conventional x-rays, micro-CT and histology.
Results:
A sufficient number of cells (mean 45x106) could be isolated from 6ml (SD ±2ml) of BM aspirate. The clonogenicity was as excpected at 0.02%. Qualitative distribution in MTT staining was homogeneous in the periphery of constructs and a high cell survival rate after 2 weeks of in-vitro culture. In-vivo results show conventional radiographs with callus formation in all animals 6 weeks after implantation. Histological analysis show marginal bone formation in constructs despite tissue ingrowth. Quantification and differences between groups are currently under investigation and will be demonstrated.
Conclusion:
In our preclinical animal study, we are able to produce stable tissue engineered bone flaps in an orthotopic small animal model. As already shown by different research groups and clinicians, tissue engineered bone constructs are a promising therapy for bone defects. In our study we will be able to show which implantation method is the most reasonable and with the established model further studies can be carried out to optimize the process. |
| Financed by |
Other sources
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29/04/2024
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