1. Department of Spinal Surgery, Institute of Neurosurgery AMS Ukraine, Kiev, Ukraine.
2. Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona.
3. Department of Surgery, Kiev City Endocrinological Center, Kiev, Ukraine.
4. Department of Surgery, Mount Zion Medical Center, UCSF, San Francisco, California.