[1] Univ Freiburg, Fac Med, Med Ctr, Dept Orthoped & Trauma Surg, Freiburg, Germany
[2] Loretto Hosp, Dept Spine Surg, Freiburg, Germany
[3] Paracelsus Med Univ, Inst Expt Neuroregenerat, Spinal Cord Injury & Tissue Regenerat Ctr Salzburg, A-5020 Salzburg, Austria
[4] Harvard Med Sch, Brigham & Womens Hosp, Dept Anesthesiol Perioperat & Pain Med, Boston, MA 02115 USA
[5] Austrian Cluster Tissue Regenerat, Vienna, Austria