1. Department of Plastic and Hand Surgery, University Hospital Regensburg, Germany
2. Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany
3. Department of Biomaterials, Central Institute for Biomedical Engineering, University of Ulm, Ulm, Germany
4. Department of Radiology, University Hospital Regensburg, Regensburg, Germany