The influence of the ""penetration-"" and the ""filling-ratios"" on the pull-out strength of transpedicular screws

Kourkoulis, SK; Chatzistergos, P

dc.contributor.author	Kourkoulis, SK	en
dc.contributor.author	Chatzistergos, P	en
dc.date.accessioned	2014-03-01T01:58:50Z
dc.date.available	2014-03-01T01:58:50Z
dc.date.issued	2009	en
dc.identifier.issn	02195194	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/28748
dc.subject	Filling ratio	en
dc.subject	Finite element method	en
dc.subject	Penetration ratio	en
dc.subject	Pull-out force	en
dc.subject	Transpedicular screws	en
dc.title	The influence of the ""penetration-"" and the ""filling-ratios"" on the pull-out strength of transpedicular screws	en
heal.type	journalArticle	en
heal.identifier.primary	10.1142/S0219519409003012	en
heal.identifier.secondary	http://dx.doi.org/10.1142/S0219519409003012	en
heal.publicationDate	2009	en
heal.abstract	The stress field developed in the human lumbar vertebral bone due to the presence of transpedicular fixation screws is studied in an attempt to quantify the force required to pull the screw out of the bone. The study is focused on the pure pull-out phenomenon, namely the case in which the external loads act parallel to the longitudinal axis of the screw. The parameters considered are the penetration ratio, i.e. the ratio of the screw length divided by the distance from the posterior pedicle entrance site to the anterior vertebral cortex, and the filling ratio, i.e. the ratio of the major diameter of the screw divided by the transverse diameter of the pedicle. The study is carried out numerically with the aid of the finite element method. The analysis takes into account both the variation of the mechanical properties of the bone in terms of the distance from its surface as well as the geometrical details of a typical transpedicular screw. The results of the analysis are compared with existing experimental data from the literature and the comparison is very satisfactory. © 2009 World Scientific Publishing Company.	en
heal.journalName	Journal of Mechanics in Medicine and Biology	en
dc.identifier.doi	10.1142/S0219519409003012	en
dc.identifier.volume	9	en
dc.identifier.issue	3	en
dc.identifier.spage	283	en
dc.identifier.epage	300	en