Affiliation: | 1. University of Pennsylvania, 3440 Market Street, Suite 370, Philadelphia, PA 19104, USA;2. Philadelphia VAMC, University and Baltimore Avenues, Philadelphia, PA 19104, USA;2. Neurosurgery Department, Amasya University Faculty of Medicine, Amasya Merkez/Amasya, Turkey;4. Neurosurgery Department, Ankara University Faculty of Medicine, Ibn-i Sina Hospital, Altindag/Ankara, Turkey |