[1] Vrije Univ Amsterdam, Dept Phys & Med Technol, Med Ctr, NL-1007 MB Amsterdam, Netherlands
[2] Vrije Univ Amsterdam, Dept Orthopaed Surg, Med Ctr, NL-1007 MB Amsterdam, Netherlands
[3] Skeletal Tissue Engn Grp Amsterdam STEGA Fdn, Res Inst MOVE, Amsterdam, Netherlands
[4] BG Clin Bergmannstrost, Dept Neurosurg, Halle, Germany