1. Department of Pharmacy, University College London Hospitals, 235 Euston Road, London, NW1 2BU, UK
2. West Hertfordshire Hospitals NHS Trust, Spinal Surgery Unit, Watford General Hospital, Vicarage Road, Watford, Hertfordshire, WD18 0HB, UK
3. Spinal Surgery, Spinal Deformity Unit, Royal National Orthopaedic Hospital NHS Trust, Middlesex, HA7 4LP, UK
4. Spinal Deformity Unit, Royal National Orthopaedic Hospital NHS Trust, Middlesex, HA7 4LP, UK