1. Department of Neurosurgery, Geisinger, Wilkes-Barre, Pennsylvania, USA;
2. Department of Neurosurgery, Geisinger, Danville, Pennsylvania, USA;
3. Department of Neurosurgery, Saarland University Medical Center, Homburg, Germany;
4. Department of Neurosurgery, Christian Doppler University Hospital, Paracelsus Medical University, Salzburg, Austria