Physicochemical properties of fixation plates used in pectus excavatum treatment

Abstract

This paper presents evaluations of surface damage and biomechanical analysis of plates made up of Cr-Ni-Mo stainless steel, used in pectus excavatum treatment. The corrosion tests were realised with the use of the potentiodynamic method. The VoltaLab? PGP 201 system for electrochemical tests was applied. The numerical analysis was performed for: the stabiliser of 460 mm length, 16 mm width and 2.5, 3.5 and 4.5 mm thickness. The tests showed that structure of the steel plates were made of the PN-ISO 5832-1 standard. On the basis of the obtained results it can be stated that the mechanical damage of the plates' surfaces are the result of fitting of the plates to the anatomical curvature of chest with the use of the surgical tool. The surface damage is induced in the given deformation regions and is a potential reason of corrosion. The numerical analysis shows that stresses in plates did not exceed the yield point: for the stainless steel Rp0,2' min = 590 MPa. Values of maximum displacements occuring in the stabilising bar in the range of clinically acceptable displacements. The obtained results are the basis for the optimisation of mechanical and physicochemical properties of the metallic biomaterial. On the basis of the obtained results it can be stated that the stainless steel can be applied in the funnel chest treatment. This paper presents the influence of surface damage and stresses and displacement of plates used in the pectus excavatum treatment on the corrosion resistance. [Received 11 April 2006; Accepted 12 March 2007]