Advisory Committee Chair
Andreaas S Anayiotos
Advisory Committee Members
Peter G Anderson
Brigitta C Brott
Jack E Lemons
Document Type
Thesis
Date of Award
2007
Degree Name by School
Master of Science in Biomedical Engineering (MSBME) School of Engineering
Abstract
In-vivo corrosion of endovascular stents presents two main risks; release of toxic metallic ions and deterioration of the mechanical properties of the stents which may lead to fracture. Several studies have reported corrosion of nickel-titanium stent wires as well as stainless steel sternal wires. It has been suggested that when corrosion occurs on the surface of implants, an amount of metallic ions equivalent to the corroded volumes is released into surrounding tissue. The purpose of this study was to analyze explanted metallic stents for corrosion. The focus was on the detection of metallic ions released into surrounding vascular tissue as well as on alterations of the stent surface due to corrosion. The explanted specimens used in this study consisted of explanted stents surrounded by vascular tissue. Therefore, a standard protocol was developed in order to digest the vascular tissue for trace elemental spectrochemical analysis at parts per billion without compromising the stent surface. Scanning electron microscopy was used to examine the surfaces of explanted stents for evidence of corrosion in terms of surface alterations. The results were summarized as follows: (a) a standard tissue digestion protocol was successfully developed using a combination of low-impurity sodium hydroxide as the digestion medium, polypropylene containers for tissue storage during digestion, and ceramic cutting tools for sectioning of specimens; (b) the metallic levels detected in tissues iii dissolved from explanted stents were significantly higher than the levels detected in controls; and (c) significant surface alterations due to biocorrosion and mechanical damage were observed on the surface of explanted stents whereas no surface alterations were observed on control stents.
Recommended Citation
Halwani, Dina, "Metal-Tissue Interactions In Early Stage Biocorrosion Of Metallic Stents" (2007). All ETDs from UAB. 3584.
https://digitalcommons.library.uab.edu/etd-collection/3584