Affiliation: | 1.Spine Unit, Schulthess Clinic, Lengghalde 2, Zurich, 8008, Switzerland ;2.Department of Orthopaedics, Hopitaux Iris Sud/IRIS South Teaching Hospitals, Brussels, Belgium ;3.Orthopädische Klinik, Salem Spital, Schänzlistrasse 39, Bern 25, 3000, Switzerland ; |