Analytical investigations on elastomeric shells of new Poly Implant Prothèse (PIP) breast and from sixteen cases of surgical explantation.

In this study we have analysed the chemical composition of the extractable components from the elastomeric shells from n=27 explanted implants (n=16 patients), n=2 new PIP implants, and from explanted Eurosilicone and McGhan implants (n=2 for each brand). Empty elastomeric PIP shells (n=2) were also available for analysis. Prostheses were explanted between 2011 and 2012, after 3-11 years of implantation. Patients presented pre- and post-operation complications of different degrees. First we evaluated the micro-structural features of the shells by phase contrast microscopy, and compared the results with those obtained using attenuated total reflectance infrared spectroscopy (ATR-FT-IR), head space gas chromatography coupled to mass spectrometry (HS-GC-MS) and GC-MS in direct injection mode. The results of these studies confirm and explain the conclusion of previous international investigations that evidenced a linear decrease of rupture rate for prostheses implanted after 2006. The analytical identification of a series of UV sensitive radical photo-initiators (0.1%-0.2% w/w), belonging to the benzophenone family, in the shells of new and explanted prostheses produced after 2006 (associated with a strong smell absent in those produced earlier), in parallel to (ii) the removal of the anti bleed barrier from their manufacturing procedure (introduced after 2001), strongly suggested that from 2007, the PIP company used a polymerisation process different from that declared, probably as a consequence of the first reports of rupture problems. In addition, the HS-GC-MS experiments demonstrated that at body temperature the diffusivity of low molecular weight (LMW) silicones present in the PIP filler silicone is significantly higher than that of LMW silicones in an approved implant.

Chemical and biochemical composition of late periprosthetic fluids from women after explantation of ruptured Poly Implant Prothèse (PIP) breast prostheses.

In this study we have analysed the chemical composition of the silicone extracted from two explanted intact PIP breast prostheses and of breast late periprosthetic fluid (LPF) samples from n=4 patients with ruptured PIP implants. The results obtained by ATR-FT-IR spectroscopy, GC-MS, reverse phase HPLC-UV/DAD, SEC-UV/DAD and contrast phase microscopy demonstrated for the first time that the cloudy, viscous LPF found in the breast of women carriers of PIP implants is a multiphasic amphiphilic silicone/serum microemulsion that can migrate through the body (via lymphatic system) to accumulate first in the lymph nodes. The GC-MS and ATR-FT-IR data indicate that low and high molecular weight silicones (chemical markers: D4-D9, L8) can penetrate the elastomeric shell and periprosthetic capsule and enter the breast tissue via the periprosthetic fluid. Also serum influx from breast tissue into via periprosthetic fluid through the capsule and shell into implant filler silicone (chemical markers: cholesterol by GC-MS, and uric acid, globulins and albumin by HPLC-DAD). To the best of our knowledge, the profile of the major constituents in PIP-induced LPF have been unequivocally characterised for the first time in this work. Further studies will be needed to evaluate the biological consequences of the current results. The potential toxicological implications of the results are discussed in the light of the current literature on the health effects of PIP implants.

Transfer standard device to improve the traceable calibration of physiotherapy ultrasound machines.

Ultrasound (US) physiotherapy as a clinical treatment is extremely common in the Western world. Internationally, regulation to ensure safe application of US physiotherapy by regular calibration ranges from nil to mandatory. The need for a portable power standard (PPS) has been addressed within a European Community (EC)-funded project. This PPS consists of an electrical driver, a set of US transducers and a cavitation detector (CD). Each component has been extensively tested for stability and travel robustness. Transducer output power has been determined with an uncertainty of <3.3% and with a long-term (2-y) output stability of better than 3%. The CD can detect bubble activity for powers above 3 W for a 1-MHz transducer. Travel trials demonstrated the utility of the PPS in practical measurement environments. Deviations in power measurements observed during these trials were mostly acceptable (<10%), although there were also examples of gross differences (>100%). The PPS is now ready to be used to underpin traceable calibration of physiotherapy devices.