[1] Catholic Univ Korea, Seoul St Marys Hosp, Dept Neurosurg, Spine Ctr, Seoul, South Korea
[2] Weill Cornell Brain & Spine Ctr, New York, NY USA
[3] Paracelsus Med Univ, Salzburg, Austria
[4] Schon Klin Munchen Harlaching, Spine Ctr, Munich, Germany