1. Department of Neurosurgery, Royal Victoria Infirmary, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom,
2. Department of General and Special Surgery, Faculty of Medicine, The Hashemite University, Zarqa, Jordan, London, United Kingdom.
3. Wessex Spinal Unit, University Hospital Southampton NHS Foundation Trust, Southampton, London, United Kingdom.
4. Department of Neurosurgery, St George’s University Hospitals NHS Foundation, London, United Kingdom.