1. Department of Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Bochum, Germany
2. Department of Pain Medicine, BG Hospital Duisburg, Duisburg, Germany
3. Department of Hand Surgery, BG Hospital Duisburg, Duisburg, Germany
4. Department of Ergotherapy, BG Hospital Duisburg, Duisburg, Germany