1. Foundation House Officer, Leeds General Infirmary, Leeds, UK;
2. Foundation House Officer, Southend University Hospital, Southend-on-Sea, UK;
3. Department of Spinal Surgery, Royal Victoria Hospital, Newcastle, UK;
4. Consultant Cardiothoracic Surgeon, Northern General Hospital, Sheffield, UK;
5. Consultant Orthopedic Spinal Surgeon, Northern General Hospital, Sheffield, UK;
6. Consultant Neurosurgeon and Spinal Surgeon, Royal Hallamshire Hospital, Sheffield, UK