Assessment of silicone gel breast implant biodurability by NMR and EDS techniques

In a study using explanted gel breast implants and appropriate nonimplanted controls, we examined silicone biodurability after long-term implantation. Using NMR spectroscopy, as well as NMR relaxometry measurements (T-2), no evidence of hydrolysis or other chemical degradation of the cross-linked silicone matrix was observed in specimens from an early breast implant model (Cronin) explanted after 32 years in vivo or a more recent Silastic (R) II model after 13 years in vivo. In addition, no appreciable differences were seen in T2 relaxation times comparing explanted breast implants to suitably-matched nonimplanted controls, further underscoring the biostability of the cross-linked silicone shell and gel. Our T-2 data and resultant interpretations differ from a 2004 report by the NMR lab at the University of Munster, highlighting the importance of suitable nonimplanted controls and sample preparation. Energy dispersive spectroscopy (EDS) was also performed, confirming the persistence of a fluorosilicone layer inside the elastomer shells of Silastic II implants. (C) 2007 Wiley Periodicals, Inc.