Document Detail


Effect of a pedicle-screw-based motion preservation system on lumbar spine biomechanics: a probabilistic finite element study with subsequent sensitivity analysis.
MedLine Citation:
PMID:  20696430     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
Pedicle-screw-based motion preservation systems are often used to support a slightly degenerated disc. Such implants are intended to reduce intradiscal pressure and facet joints forces, while having a minimal effect on the motion patterns. In a probabilistic finite element study with subsequent sensitivity analysis, the effects of 10 input parameters, such as elastic modulus and diameter of the elastic rod, distraction of the segment, level of bridged segments, etc. on the output parameters intervertebral rotations, intradiscal pressures, and facet joint forces were determined. A validated finite element model of the lumbar spine was employed. Probabilistic studies were performed for seven loading cases: upright standing, flexion, extension, left and right lateral bending and left and right axial rotation. The simulations show that intervertebral rotation angles, intradiscal pressures and facet joint forces are in most cases reduced by a motion preservation system. The influence on intradiscal pressure is small, except in extension. For many input parameter combinations, the values for intervertebral rotations and facet joint forces are very low, which indicates that the implant is too stiff in these cases. The output parameters are affected most by the following input parameters: loading case, elastic modulus and diameter of the elastic rod, distraction of the segment, and angular rigidity of the connection between screws and rod. The designated functions of a motion preservation system can best be achieved when the longitudinal rod has a low stiffness, and when the connection between rod and pedicle screws is rigid.
Authors:
Antonius Rohlmann; Hadi Nabil Boustani; Georg Bergmann; Thomas Zander
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-08-08
Journal Detail:
Title:  Journal of biomechanics     Volume:  43     ISSN:  1873-2380     ISO Abbreviation:  J Biomech     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-08     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0157375     Medline TA:  J Biomech     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2963-9     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Ltd. All rights reserved.
Affiliation:
Julius Wolff Institute, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. antonius.rohlmann@charite.de
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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