1. Department of Neurosurgery, Leiden University Medical Center, Leiden;
2. Department of Neurosurgery, Haaglanden Medical Center, The Hague;
3. Center of Excellence for Rehabilitation Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht and De Hoogstraat Rehabilitation, Utrecht;
4. Department of Rehabilitation Medicine, University Medical Center Groningen, University of Groningen;
5. Department of Neurosurgery, Amsterdam University Medical Centers, Amsterdam;
6. Department of Orthopedic Surgery, University Medical Center Utrecht; and
7. Department of Neurosurgery, University Neurosurgical Center Holland, Leiden University Medical Center Leiden, Haaglanden Medical Center and Haga Teaching Hospital, The Hague, The Netherlands