1. Department of Neurosurgery, Aalborg University Hospital, Aalborg, Denmark.
2. University of Copenhagen, Copenhagen, Denmark.
3. Department of Anesthesia and Trauma Centre, Centre of Head and Orthopedics, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
4. The Danish Air Ambulance, Aarhus, Denmark.
5. Department of Orthopedic Surgery, Aalborg University Hospital, Aalborg, Denmark.