1. Division of Pain Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, Palo Alto, CA USA
2. Rehabilitation Services, Stanford Health Care, Stanford, CA, USA
3. Institute for Health Sciences, Zurich University of Applied Sciences, Winterthur, Switzerland
4. Department of Anesthesiology and Pain Management, University of Washington, Seattle, Washington, USA
5. Curtin University Medical School, Bentley, Australia
6. University of Western Australia Medical School, Perth, Australia