1. Research Department, Spine Centre of Southern Denmark, Hospital Lillebaelt, Middelfart, Denmark
2. Institute of Regional Health Research, University of Southern Denmark, Odense, Denmark
3. Department of Radiology, Aarhus University Hospital, Aarhus, Denmark
4. Research and Development, Military Rehabilitation Centre Aardenburg, Doorn, The Netherlands
5. Department of Physiotherapy, HU University of Applied Sciences, Utrecht, The Netherlands