1. Department of Anesthesiology, University Medical Centre Goettingen, Goettingen, Germany
2. Department of Orthopedics and Traumatology, Medical University Innsbruck, Innsbruck, Austria
3. Department of Anesthesiology and Intensive Care Medicine, Medical University Innsbruck, Innsbruck, Austria
4. Department of Mathematics, Faculty of Mathematics, Computer Science and Physics, University of Innsbruck, Innsbruck, Austria
5. Department of Radiology, Medical University Innsbruck, Innsbruck, Austria
6. Department of Anesthesiology and Intensive Care Medicine, St. John of God Hospital, Paracelsus Medical University, Salzburg, Austria