1. Department of Spine Surgery, 7th Navy Hospital, Polanki 117, 80-305 Gdańsk, Poland
2. Department of Neurosurgery, 1st Military Clinical Hospital in Lublin—Branch in Ełk, Tadeusza Kościuszki 30, 19-300 Ełk, Poland
3. Department of Neurosurgery, Dietrich-Bonhoeffer-Klinikum, Salvador-Allende-Straße 30, 17036 Neubrandenburg, Germany
4. Department of Neurosurgery, Mazovian Bródno Hospital, Kondratowicza 8, 03-242 Warsaw, Poland
5. Department of Neurosurgery, Centre of Postgraduate Medical Education, Kondratowicza 8, 03-242 Warsaw, Poland
6. Interventional Neurotherapy Center, Mazovian Bródno Hospital, Kondratowicza 8, 03-242 Warsaw, Poland