[1] Swiss Fed Inst Technol, Inst Biomech, Dept Hlth Sci & Technol, Hoenggerbergring 64, CH-8093 Zurich, Switzerland
[2] Cantonal Hosp St Gallen, Dept Oncol & Hematol, St Gallen, Switzerland
[3] Univ Utah, Dept Bioengn, Salt Lake City, UT 84112 USA
[4] Univ Utah, Dept Orthopaed, Salt Lake City, UT USA
[5] Schon Klin Munchen Harlaching, Spine Ctr, Munich, Germany
[6] Paracelsus Private Med Univ Salzburg, Acad Teaching Hosp & Spine Res Inst, Salzburg, Austria
[7] Univ Potsdam, Dept Hlth Sci, Potsdam, Germany