1. Department of Neurosurgery, University of Milan, Milan, Italy
2. Department of Neurosurgery, Lugano Regional Hospital, Lugano, Switzerland
3. Istituti Clinici di Perfezionamento, Orthopaedic Trauma Center, Rehabilitation Center for Spinal Cord Injuries, Milan, Italy
4. Department of Neurosurgery, Fondazione IRCCS Ca' Granda–Ospedale Maggiore Policlinico, Milan, Italy