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Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw
BACKGROUND: The pullout strength of pedicle screws is influenced by many factors, including diameter of the screws, implant design, and augmentation with bone cement such as PMMA. In the present study, the pullout strength of an innovative fenestrated screw augmented with PMMA was investigated and w...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4422437/ https://www.ncbi.nlm.nih.gov/pubmed/25949274 http://dx.doi.org/10.1186/s13013-015-0039-6 |
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author | Christodoulou, Evangelos Chinthakunta, Suresh Reddy, Divya Khalil, Saif Apostolou, Thomas Drees, Philipp Kafchitsas, Konstantinos |
author_facet | Christodoulou, Evangelos Chinthakunta, Suresh Reddy, Divya Khalil, Saif Apostolou, Thomas Drees, Philipp Kafchitsas, Konstantinos |
author_sort | Christodoulou, Evangelos |
collection | PubMed |
description | BACKGROUND: The pullout strength of pedicle screws is influenced by many factors, including diameter of the screws, implant design, and augmentation with bone cement such as PMMA. In the present study, the pullout strength of an innovative fenestrated screw augmented with PMMA was investigated and was compared to unaugmented fenestrated, standard and dual outer diameter screw. METHODS: Twenty four thoracolumbar vertebrae (T10-L5, age 60 to 70 years) from three cadavers were implanted with the four different pedicle screws. Twelve screws of each type were instrumented into either left or right pedicle with standard screw paired with unaugmented and dual outer diameter screw paired with augmented fenestrated screw in any given vertebra. Axial pullout testing was conducted at a rate of 5 mm/min. Force to failure (Newtons) for each pedicle screw was recorded. RESULTS: The augmented fenestrated screws had the highest pullout strength, which represented an average increase of 149%, 141%, and 78% in comparison to unaugmented, standard, and dual outer diameter screws, respectively. Pullout strength of unaugmented screws was comparable to that of standard screws, however it was significantly lower than dual outer diameter screws. CONCLUSIONS: Fenestrated screws augmented with PMMA improve the fixation strength and result in significantly higher pullout strength compared to dual outer diameter, standard and unaugmented fenestrated screws. Screws with dual outer diameter provided enhanced bone-screw purchase and may be considered as an alternative technique to increase the bone-screw interface in cases where augmentation using bone cement is not feasible. Unaugmented screws can be left in the pedicle even without cement and provide similar pullout strength to standard screws. |
format | Online Article Text |
id | pubmed-4422437 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-44224372015-05-07 Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw Christodoulou, Evangelos Chinthakunta, Suresh Reddy, Divya Khalil, Saif Apostolou, Thomas Drees, Philipp Kafchitsas, Konstantinos Scoliosis Research BACKGROUND: The pullout strength of pedicle screws is influenced by many factors, including diameter of the screws, implant design, and augmentation with bone cement such as PMMA. In the present study, the pullout strength of an innovative fenestrated screw augmented with PMMA was investigated and was compared to unaugmented fenestrated, standard and dual outer diameter screw. METHODS: Twenty four thoracolumbar vertebrae (T10-L5, age 60 to 70 years) from three cadavers were implanted with the four different pedicle screws. Twelve screws of each type were instrumented into either left or right pedicle with standard screw paired with unaugmented and dual outer diameter screw paired with augmented fenestrated screw in any given vertebra. Axial pullout testing was conducted at a rate of 5 mm/min. Force to failure (Newtons) for each pedicle screw was recorded. RESULTS: The augmented fenestrated screws had the highest pullout strength, which represented an average increase of 149%, 141%, and 78% in comparison to unaugmented, standard, and dual outer diameter screws, respectively. Pullout strength of unaugmented screws was comparable to that of standard screws, however it was significantly lower than dual outer diameter screws. CONCLUSIONS: Fenestrated screws augmented with PMMA improve the fixation strength and result in significantly higher pullout strength compared to dual outer diameter, standard and unaugmented fenestrated screws. Screws with dual outer diameter provided enhanced bone-screw purchase and may be considered as an alternative technique to increase the bone-screw interface in cases where augmentation using bone cement is not feasible. Unaugmented screws can be left in the pedicle even without cement and provide similar pullout strength to standard screws. BioMed Central 2015-05-01 /pmc/articles/PMC4422437/ /pubmed/25949274 http://dx.doi.org/10.1186/s13013-015-0039-6 Text en © Christodoulou et al.; licensee BioMed Central. 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Christodoulou, Evangelos Chinthakunta, Suresh Reddy, Divya Khalil, Saif Apostolou, Thomas Drees, Philipp Kafchitsas, Konstantinos Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw |
title | Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw |
title_full | Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw |
title_fullStr | Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw |
title_full_unstemmed | Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw |
title_short | Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw |
title_sort | axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4422437/ https://www.ncbi.nlm.nih.gov/pubmed/25949274 http://dx.doi.org/10.1186/s13013-015-0039-6 |
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