1. Department of Neurosurgery, Royal Hallamshire Hospital, Sheffield, UK;
2. Department of Neurosurgery, The Royal London Hospital, Barts Health NHS Trust, London, UK;
3. Department of Neurosurgery, South West Neurosurgical Centre, Derriford Hospital, Devon, UK;
4. Department of Neurosurgery, Leeds General Infirmary, Leeds, UK;
5. National Hospital for Neurology and Neurosurgery, Queen Square, London, UK