1. Acupuncture Research Group, Dusseldorf, Germany.
2. Department of Medical Informatics, Biometry and Epidemiology, Ruhr-University Bochum, Bochum, Germany.
3. Department of Community and Family Medicine and the Center for Clinical Health Policy Research, Duke University, NC, USA.
4. Department of Neurology, University Essen, Essen, Germany.
5. Klinik für Orthopädie, Ruhr-University Bochum, Bochum, Germany.
6. Center for Integrative Pain Management, Dusseldorf, Germany.
7. Center for Neurosensory Disorders, University of Chapelhill, NC, USA.