1. Department of Anesthesiology, Ludwig-Maximilians-University, Munich, Germany
2. Interdisciplinary Pain Centre, Klinikum Landsberg am Lech, Germany
3. Technical University of Munich, Germany; TUM School of Medicine, Germany
4. Institute for Medical Information Processing, Biometry and Epidemiology, Ludwig-Maximilians-University Munich, Germany
5. Department of Pain Medicine, Munich Hospital Schwabing, Germany