1. Department of Orthopaedics, Trauma Surgery and Plastic Surgery, University of Leipzig, Leipzig, Germany
2. Department of Trauma and Orthopedic Surgery, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
3. Department of Orthopedics and Trauma Surgery, University hospital, Duesseldorf, Germany
4. Center for Spinal and Scoliosis Surgery, Malteser Waldkrankenhaus St. Marien gGmbH, Erlangen, Germany
5. Department of Orthopedics and Traumatology, Paracelsus Private Medical University Nuremberg, Nuremberg, Germany