1. Department of Neurosurgery, Peoples’ Friendship University of Russia, Moscow, Russian Federation,
2. Department of Neurosurgery, Dr. Alejandro Cabral Hospital, San Juan de la Maguana, Dominican Republic,
3. Department of Spine Surgery, Central Clinical Hospital of the Russian Academy of Sciences, Moscow, Russian Federation,
4. Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Charitéplatz, Berlin, Germany,