1. Depatment of Oncologic and Degenerative Spine Surgery, Rizzoli Orthopaedic Institute, 40136 Bologna, Italy
2. Spine Center Munich, Orthopedic Hospital München-Harlaching, Grünwalderstr aße 51, 81547, Munich, Germany
3. Division of Orthopaedic Spine Surgery, Department of Orthopaedics, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4
4. Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA