1. Department of Nephrology, Dialysis Division, Fahad Bin Jassim Kidney Center, Hamad General Hospital, Hamad Medical Corporation, Doha P.O. Box 3050, Qatar
2. Division of Health Care Sciences, Dresden International University, Freiberger Str. 37, 01067 Dresden, Germany
3. Department of Neurosurgery, Division of Spine Surgery, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
4. Department of Surgery, Klinikum Chemnitz gGmbH, Medical Faculty and University Hospital Carl Gustav Carus, Medical Campus Chemnitz, Technische Universität Dresden, Flemmingstraße 2, 09116 Chemnitz, Germany
5. Department of Neurology, Technische Universität Dresden, Medical Faculty and University Hospital Carl Gustav Carus, Fetscherstrasse 74, 01307 Dresden, Germany