1. Department of Cell BiologyPoznan University of Medical Sciences Rokietnicka 5D 60‐806 Poznań Poland
2. Department of Pediatric Orthopedics and TraumatologyPoznan University of Medical Sciences Poznań Poland
3. Department of Spine Disorders and Pediatric OrthopedicsPoznan University of Medical Sciences Poznań Poland
4. Department of Medical StatisticsUniversity of Warsaw Warsaw Poland