1. Department of Pediatric Orthopedic Surgery and Traumatology, University Children’s Hospital, Waszyngtona 17, 15-274 Bialystok, Poland
2. Paley European Institute, Al. Rzeczypospolitej 1, 02-972 Warsaw, Poland
3. Department of Neurosurgery, University of North Carolina, Chapel Hill, NC 27516, USA
4. 2nd Clinical Department of General and Gastroenterogical Surgery, Medical University of Bialystok, ul. M. Skłodowskiej-Curie 24a, 15-276 Bialystok, Poland
5. Department of Orthopedics and Traumatology, Helsinki University Hospital, 00260 Helsinki, Finland