1. Department of Neurosurgery, Virginia Commonwealth University, Richmond, Virginia.
2. Department of Neurosurgery, University of Messina, Messina, Italy.
3. Department of Neurosurgery, Kantonsspital Aarau, Aarau, Switzerland.
4. Department of Neurosurgery, Institute of Neurosurgical Pathophysiology, Johannes Gutenberg University of Mainz, Mainz, Germany.