Andrew Quaile1, Marius M Scarlat2, Andreas F Mavrogenis3, Cyril Mauffrey4. 1. Hampshire Clinic, Spineworks Basingstoke, Hampshire, RG24 7AL, UK. 2. Clinique St. Michel, Group ELSAN, Toulon, France. mscarlat@gmail.com. 3. First Department of Orthopaedics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece. 4. Department of Orthopedics Denver Health Medical Center, University of Colorado School of Medicine, Denver, CO, USA.