Abstract
Purpose: Deeper insights into the mechanical behavior of lumbar disc prostheses are required. Prior studies on the biomechanical performance of artificial discs were mostly performed with finite element analyses, but this has never been analyzed with altering articulate curvature. This study aimed to ascertain the influence of the geometry of a ball-and-socket disc prosthesis for the lumbar spine. Materials and Methods: Three-dimensional finite element model of human L4-L5 was reconstructed. Convex, concave, and elliptic artificial disc models were also established with Computer-Aided-Design software. Simulations included: (1) three articulate types of polyethylene (PE) insert were implanted inferiorly and (2) concave and convex PE inserts were implanted on the superior or inferior sides in flexion/extension, lateral bending, and axial rotation in the lumbar spine. Shear stresses and von Mises stresses on PE insert were assessed for their loading distributions. Results: High shear stresses of all articulate types occurred in flexion, and convex PE insert performed the maximum stress of 23.81 MPa. Under all conditions, stresses on concave PE inserts were distributed more evenly and lower than those on the convex type. Elliptic geometry enabled confining the rotation of the motion unit. The shear force on the convex PE insert on the inferior side could induce transverse crack because the shear stress exceeded yielding shear stress. Conclusions: The concave PE insert on the inferior side not only decreased loading concentration but had relatively low stress. Such a design may be applicable for artificial discs.
J Appl Biomater Funct Mater 2012; 10(2): 107 - 112
Article Type: ORIGINAL RESEARCH ARTICLE
DOI:10.5301/JABFM.2012.9258
Authors
Hung-Wen Wei, Yueh-Feng Chiang, Yu-Wen Chen, Cheng-Kung Cheng, Yang-Hwei Tsuang
Article History
- • Accepted on 18/06/2011
- • Available online on 22/06/2012
- • Published online on 27/09/2012
This article is available as full text PDF.
Authors
- Wei, Hung-Wen
[PubMed]
[Google Scholar]
Department of Physical Therapy and Assistive Technology, National Yang Ming University, Taipei - Taiwan
- Chiang, Yueh-Feng
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[Google Scholar]
Department of Orthopaedic Surgery, Buddhist Tzu Chi General Hospital, Taichung branch, Taichung - Taiwan and Orthopaedic Biomechanics Laboratory, Institute of Biomedical Engineering, National Yang Ming University, Taipei - Taiwan
- Chen, Yu-Wen
[PubMed]
[Google Scholar]
Orthopaedic Biomechanics Laboratory, Institute of Biomedical Engineering, National Yang Ming University, Taipei - Taiwan
- Cheng, Cheng-Kung
[PubMed]
[Google Scholar]
Orthopaedic Biomechanics Laboratory, Institute of Biomedical Engineering, National Yang Ming University, Taipei - Taiwan
- Tsuang, Yang-Hwei
[PubMed]
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Department of Orthopaedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City - Taiwan
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