1. Department of Pediatrics, Mälar Hospital, Eskilstuna, Sweden
2. Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
3. Capio Spine Center Stockholm, Löwenströmska Hospital, Upplands-Väsby, Sweden
4. Department of Medical Sciences, Örebro University, Örebro, Sweden
5. Department of Surgical Sciences, Uppsala University, Uppsala, Sweden