1. Department of Neurosurgery, University of Louisville, Louisville, Kentucky, USA
2. Department of Neurosurgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
3. Department of Neurosurgery, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Henan University People's Hospital, Henan University School of Medicine, Zhengzhou, China
4. Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
5. Department of Neurosurgery, All India Institute of Medical Science, New Delhi, India
6. Neurosurgery One, Littleton, Colorado, USA