RESUMO
The behavior of the ASTM F1058 wrought cobalt-chromium-nickel-molybdenum-iron alloy (commonly referred to as Elgiloy or Phynox) is evaluated in terms of mechanical properties, magnetic resonance imaging, corrosion resistance, and biocompatibility. The data found in the literature, the experimental corrosion and biocompatibility results presented in this article, and its long track record as an implant material demonstrate that the cobalt superalloy is an appropriate material for permanent surgical implants that require high yield strength and fatigue resistance combined with high elastic modulus, and that it can be safely imaged with magnetic resonance.
Assuntos
Ligas/química , Materiais Biocompatíveis/química , Cobalto/química , Próteses e Implantes/efeitos adversos , Ligas/efeitos adversos , Animais , Materiais Biocompatíveis/efeitos adversos , Sobrevivência Celular/efeitos dos fármacos , Cobalto/efeitos adversos , Corrosão , Cobaias , Hemólise/efeitos dos fármacos , Hipersensibilidade Tardia , Imageamento por Ressonância Magnética , Testes de Mutagenicidade , CoelhosRESUMO
Stents are tubular devices that are used in cylindrical passages of the body following trauma or disease in order to keep the cross section of these passages open. A mathematical model of a self-expanding metallic stent has been developed with the aim of predicting various geometrical and mechanical properties of the stent. The model was developed with the main assumptions that the stent acts as a combination of a number of independent open-coiled helical springs with ends fixed against rotation, and that the springs undergo elastic deformations only. A series of experiments has been carried out in order to assess the validity of the model. The experimental results show good agreement with theory for the tests involving stent diameter and longitudinal force as a function of stent length and fair agreement, limited by frictional effects, for the tests involving radial pressure as a function of stent diameter.