1 Department of Neurosurgery, Christian-Doppler-Klinik, Paracelsus Private Medical University, Salzburg, Austria.
2 Department of Neurosurgery, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany.
3 Department of Neurosurgery, Christian-Doppler-Klinik, Paracelsus Private Medical University, Salzburg, Austria. Electronic address: [email protected].