1. RKC Centre for Spine Surgery in Stockholm, Sweden;
2. Spine Center Göteborg, Västra Frölunda, Sweden;
3. Department of Infectious Diseases, Institute of Biomedicine, University of Gothenburg, Sweden;
4. Sahlgrenska University Hospital, Göteborg, Sweden;
5. Department of Cell and Molecular Biology, Biomedical, Center, Uppsala University, Sweden;
6. Department of Neuroradiology, Karolinska University, Hospital, Stockholm, Sweden;
7. Spine Unit, Ortopaedkirurgisk Afdeling, Sjaellands, Universitetshospital, Køge, Denmark;
8. Spine Center of Southern Denmark, Lillebaelt Hospital, Middelfart, Denmark