Silicon implants

Ikada Y. Surface modification of polymers for medical application. Biomaterials, 1994, 15, 725-736. James SJ, Pogribna M, Miller BJ, Bolon B, and Muskhelishvili L. Characterization of cellular response to silicone implants in rats Implications for foreign-body carcinogenesis. Biomaterials, 1997, 18, 667-675. 

In Chapter 4.7 we have given examples of the application of the technique to both polymers and to silicon implanted with P. In the latter case it appears that NRA has a better reproducibility than SIMS in the determination of ultrashallow dopant profiles. Demortier (2000) also presents examples of applications of NRA to archaeological and biological materials. 

Fig. 6. Measured angular scans through the major axes in silicon implanted with 2H at 30 K and pre-irradiated with 3He ions before analysis. The experimental data is shown together with fits using the SE model (see text). Dotted lines show the signals of the bond center (BC) site and the tetrahedral interstitial (T) site, the two sites used in the fit. (Reprinted with permission from the American Physical Society, Nielsen, B.B. (1988). Phys. Review B 37, 6353.)...

Many women who have received silicone-fluid-filled breast implants have claimed to suffer from implant-related diseases, apparently caused by small leakages of the fluid into the body tissue. Successful lawsuits on those grounds in the United States have driven Dow Corning, the principal manufacturer of the implants, to file for bankruptcy protection. Food and Drug Administration Commissioner David A. Kessler, however, has reported to a congressional subcommittee that, as of July, 1995, there was no scientific evidence that silicone implants are a significant cause of disease. See M. S. Reisch and R. L. Rawls, Silicone gel breast implants. Chem. Eng. News, December 11, 10-17 (1995). 

CONTROLLED DRUG DELIVERY SYSTEMS SILICONE IMPLANTS... 

The most common compounds used for implants are silicones, fluoropolymers, and polyurethanes. Although at one time silicone implants were thought to lead to autoimmune and rheumatic disorders, these studies were likely flawed and such compounds are now once again used for surgical implants.58... 

Qui H, Hedlund L, Neuman M, Edwards C, Black R, Cofer G, Johnson GA. Measuring the progression of foreign body reaction to silicone implants using in vivo microscopy. IEEE Transactions on Biomedical Engineering 1998, 45, 921-926. 

Silicone implants sometimes provoke systemic adverse effects. More than 20 women developed muscle pain, joint pain and swelling, pulmonary disease including pleural effusions, pulmonary infiltrates, and reduced pulmonary diffusing capacity, dry eyes, dysphagia, bladder dysfunction, neurological abnormalities, and skin disease (including localized and diffuse scleroderma-hke changes) (9). 

Spiera H, Kerr LD. Scleroderma following silicone implantation a cumulative experience of 11 cases. J Rheumatol 1993 20(6) 958-61. 

Gutierrez FJ, Espinoza LR. Progressive systemic sclerosis complicated by severe hypertension reversal after silicone implant removal. Am J Med 1990 89(3) 390-2. 

Atkinson RE, Smith RJ. Silicone synovitis following silicone implant arthroplasty. Hand Clin 1986 2(2) 291-9. 

Nalbandian RM, Swanson AB, Maupin BK. Long-term silicone implant arthroplasty. Implications of animal and human autopsy findings. JAMA 1983 250(9) 1195-8. 

A similar passivation effect was reported by Mezey et al. for silicon implanted with 10 - 10 Ge" and The tendency for thermal oxidation at 900°C... 

Despite of the silicon breast implant campaign which is a serious issue in the United States but evidently not in the rest of the world, the above statement on the environmental impact of silicones is also applicable to the impact on health of silicon medical devices and silicon implants, which are daily used in hospitals worldwide due to their excellent biocompatibility to human tissue and blood [11-13] There is also a long lasting experience clinically documented over decades on their reliability in specific applications. 

Figure 8.2. Selective tungsten using silicon implantation, a) Mo is used as an implant mask, b) after removal of the Mo mask, c) after selective tungsten deposition.

The scale of the response to this issue provides a case history that highlights another skill and training required within pharmaceutical medicine, namely crisis management. This is a very important technique which is critical in addressing substantive health issues. In a relatively recent history of healthcare, there have been several such issues, for example Zomax, Oraflex, Tylenol tampering, toxic shock syndrome, Reye s syndrome, the Dalcon shield, contaminated blood supply, silicon implants and the so-called generic drug scandal , to mention but a few. 

Figure 10, Improvement in short term hemocompatibility of silicone-g-NVP over silicone. Implants for 7 days in lamb carotid arteries.

There seems to be no absorption study of Cd in silicon. Two Cd acceptor levels have been detected in DLTS investigations of silicon implanted with radioactive mIn transmuting into mCd [107]. However, the case of Cd in silicon seems to be more complex than the other group-II elements as a donor state seemingly associated with substitutional Cd has been identified by ESR under TEC at LHeT [128]. 

Bridges AJ, Anderson JD, Burns DE, Kemple K, Kaplan JD, Lorden T (1996) Autoantibodies in patients with silicone implants. CurrTop Microbiol Immunol, 210 277-282. 

An example of the measurement of a disorder distribution is shown in Fig. 8.10 for a silicon implant at a substrate temperature of -150°C, with 5 x 1014 boron ions cuf2 at an energy of 200 keV, analyzed at room temperature with 1.8-MeV ions. The open circles in the upper part of the curve are the aligned yield. The dashed curve is the dechanneled fraction determined by use of the iterative procedure using multiple scattering theory to obtain the dechanneling factor at,. In this procedure, for example, the number of displaced atoms represented by the... 

In the field of medicine, biomimetic solutions and products span the range from externally worn biomimetic devices that augment the function of sensory organs such as hearing aids and artificial corneas to implantable biomimetic devices. Implantable devices function as (i) simple physical replacements including silicone implants used in cosmetology, dentures and dental implants, and artificial... 

Silicone was first used for breast implants in the 1960s for women who had undergone mastectomies, surgical removal of their breasts. Silicone implants later became popular with women who had no medical problems, but wanted larger breasts. By the 1980s, many women with breast implants... 

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