title: Experimental investigation of durability of transpedicular screw - vertebra connection.
abstract: Background. In this paper are presented problems with the usage of transpedicular spine fixators. The purpose of this work was to define the value of pull-out strength of transpedicular screw from vertebrae. Impact of geometrical parameters of transpedicular screw (length and diameter of screw thread part, screw design) on value of pull-out strength was analysed.<br /> Material and methods. Investigation was carried out on cadaver of lumbar and thoracic vertebrae. There were analysed 20 vertebrae and 7 transpedicular screws. All biomechanical testing was performed on material testing machine (MTS 858 MiniBionix Test System). <br /> Results. This study proved that pedicle screw diameter, and screw length have a significant effect on straight axial pull-out strength. This study proved also that very important, for good performance of the vertebrae and pedicle screw unit, is adequate match of the screw diameter up with the pedicle diameter. <br /> Conclusion. The results of investigation showed significance of geometrical parameters of transpedicular screws on durability of screw-vertebra connection. This study proved also that very important for good performance of the vertebrae and pedicle screw unit is adequate match of the screw diameter up with the pedicle diameter.
authors.affiliation: Politechnika Wrocławska, Instytut Konstrukcji i Eksploatacji Maszyn, Zakład Inzynierii Biomedycznej i Mechaniki Eksperymentalnej.
authors.forename: Jarosław
authors.initials: J
authors.lastname: Filipiak
authors.forename: Celina
authors.initials: C
authors.lastname: Pezowicz