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I.A.S. IMPLANT AWARENESS SOCIETY 102 - 6086 Boundary Drive West Surrey, B.C. V3X 2B3 Telephone: (604) 572-8486 e-mail: adellaem@shaw.ca People with McGhan implants may find these excerpts interesting. The first is: No date. Stamped MC 8790, document # 0304661 (as written except my caps). McGhan Medical Corp., Polymer Coated Mammary Implant Program General Information Silicone elastomer used in implantable devices consists of three ingredients of widely varying biocompatibilities: 1. Pure Silicone Polymer - most offer, polydimenthylsiloxane [sic] or pure polydiphensylsiloxane. 2. Reinforcing Filler (Fumed Silica) - used to increase the tensile strength of pure silicone polymer. 3. Vulcanizing Agent - very low concentration of Platinum catalyst (approximately 5 parts per million) which when mixed with the functional polymer and crosslinker promotes vulcanization. Pure silicone polymer is (one) of the most biologically compatible materials known to man, whereas SILICA FILLER IS AN EXTREME TISSUE IRRITANT. (The very small concentration of platinum renders its biocompatibility insignificant.) ONE MAY QUESTION WHY A MATERIAL WITH EXCELLENT BIOCOMPATIBILITY IS COMBINED WITH A KNOWN TISSUE IRRITANT. The answer lies in the need to increase the tensile strength (the ability) to stretch without breaking) of the implant shell. Basic Concept - Pure Polymer Coating Silicone elastomer - one of the most popular alloplasty materials used in implantable devices - has one undesirable factor: silica reinforcing filler. Use of silica filler has been under attack for many years. In 1970, E. Nyilas reported that extruded and injection moulded silicones have exposed fumed silica particles at their surfaces. In 1974, T. Kolobow reported that blood clotting time with silicone elastomer containing filler was less than half that compared to pure silicone polymer. Scientific studies concerning the relative biocompatibilities of silicone elastomer and pure silicone polymer are numerous. NOTE by nurse Boone: This is the first time I remember seeing anything about shortened clotting times. Many women have very high anticardiolipin antibodies and are at risk for blood clots. Wonder if the association is to silica!! And if silica filler had been under attack for many years, why did they go ahead and use it anyway, and why argue the harmful effects now? Document marked MC 8791, document # 0304662 continues General Information. There are three basic theories as to why the biocompatibility performance studies have consistently shown greater tissue compatibility with the pure silicone polymer, as compared with silica-filled silicone elastomer. 1. Electrical Charge - Silica has a positive charge as compared with living tissue which has a negative charge. THIS COMBINATION IS BELIEVED TO BE INCOMPATIBLE OVER A LONG TIME PERIOD. 2. Surface Smoothness - The surface topography of silicone elastomer is shown to be somewhat coarse. Pure silicone polymer with zero silica filler aggregates appears smooth. 3. Exposed Silica Particles - As discussed earlier the possibility of exposed silica particles on the implantable devices surface does exist. The McGhan Polymer Coated Device Taking into consideration all of the known information and technology available, the following conclusions have been made: 1. SILICA REINFORCING FILLER IS A KNOWN TISSUE IRRITANT, BUT IS ALSO NECESSARY IN PROVIDING THE REQUIRED PHYSICAL CHARACTERISTIC NEEDED TO PRODUCE A VIABLE SILICONE IMPLANT. NOTE by nurse Boone: Was there any consideration to the viability of the woman? 2. Pure silicone polymer coatings have been used in the past to mask conventional silicone elastomer from contact with blood in lung membrane applications. This coating technology has been reported on several occasions in the scientific literature with excellent success. In January of 1977, a polymer coated mammary implant project was initiated at McGhan Medical utilizing known scientific information and McGhan Medical’s silicone technology. The objective of the above program is to develop and produce a new generation mammary implant which hopefully will lessen the fibrous contracture complication associated with breast augmentation. Other documents of interest show the increasing amounts of platinum catalyst used in their implants as the experiment on women continued: McGhan Medical Master Formula for Silicone Dispersion (Internal) Documents stamped MCG 183335, 183336, 183339 Platinum Catalyst P/N 3103 Original date? Platinum Catalyst 28.5 - 142.8 ppm Xylene 150 - 233 parts From 2/22/78 Platinum Catalyst 257 ppm From 7/19/83 Platinum Catalyst 228 - 428 ppm Looks like the quality control was absent on the latter platinum. Just throw in whatever you want today guys. No big deal. I also have a couple of other non-MDL documents showing chemical analysis of a Dow and a Mentor implant. The amount of platinum in the envelopes is 8 to 9 times higher than in the gel. Mentor being higher. I think it is important for women who are getting saline implants to know that they are still getting fumed silica and platinum. |