1. Staff Anesthesiologist and Clinical Lecturer, Department of Anaesthesia and Pain Medicine, Royal Perth Hospital, Perth, Western Australia, Australia, and Staff Anesthesiologist, Department of Anesthesiology and Intensive Care, Muenster University Hospital, Muenster, Germany.
2. Staff Anesthesiologist, Department of Anesthesiology and Intensive Care.
3. Professor, Department of Anesthesiology and Intensive Care, Catholic Hospital Bochum, Hospital Ruhr University, Bochum, Germany.
4. Professor, Department of Spine Surgery.
5. Professor, Department of Anesthesiology and Intensive Care, St. Franziskus Hospital Muenster, Muenster, Germany.
6. Associate Professor, Department of Orthopedic Surgery, Muenster University Hospital.