Document Detail


Fixation Strength of PMMA-augmented Pedicle Screws After Depth Adjustment in a Synthetic Bone Model of Osteoporosis.
MedLine Citation:
PMID:  23027489     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
The purpose of this study was to determine the change of fixation strength after adjusting the height of polymethylmethacrylate (PMMA)-augmented pedicle screws.Cement-augmented cannulated pedicle screws with or without PMMA augmentation with a radial hole in the distal third of the screw thread were inserted into synthetic bone blocks used to model osteoporosis. Screws were left unchanged (in situ), screwed in 3 threads, or screwed out 3 threads. The change in screw height was made 24 hours after cement placement. Radiographs of the samples were taken before and after screw adjustment, and pullout strength testing was performed. In the cement group, a radiolucent cavity was present after screwing in due to the screw-cement complex migrating downward, whereas no obvious change in the boneicement complex existed after screwing out. Mean pullout strength was significantly higher in the groups with cement as compared to those without cement. However, in the cement groups, the screw-in group had the lowest mean pullout strength among 3 groups, and the mean pullout strength in the screw-out group was also significantly lower than that in the in situ group (P<.05).Adjustment of pedicle screw height after cement augmentation in a severely osteoporotic spine can significantly reduce the pullout strength of the screw.
Authors:
Szu-Han Ying; Hung-Chan Kao; Ming-Chau Chang; Wing-Kuang Yu; Shih-Tien Wang; Chien-Lin Liu
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Orthopedics     Volume:  35     ISSN:  1938-2367     ISO Abbreviation:  Orthopedics     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-02     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7806107     Medline TA:  Orthopedics     Country:  United States    
Other Details:
Languages:  eng     Pagination:  e1511-6     Citation Subset:  IM    
Copyright Information:
Copyright 2012, SLACK Incorporated.
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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