1. Trauma Research Unit, Department of Surgery, Erasmus MC University Hospital , Rotterdam, South-Holland 3015 GD, the Netherlands
2. Department of Surgery, Alrijne Hospital , Leiderdorp, South-Holland 2353 GA, the Netherlands
3. Defense Healthcare Organization, Ministry of Defense , Den Haag, South-Holland 2511 CB, the Netherlands
4. Department of Neurosurgery, Erasmus MC University Hospital , Rotterdam, South-Holland 3015 GD, the Netherlands
5. Department of Surgery, Leiden University MC , Leiden, South-Holland 2333 ZA, the Netherlands