Aesth Plast Surg DOI 10.1007/s00266-014-0347-x
LETTER TO THE EDITOR
BREAST
Clear to Cloudy: Silicone Breast Implants In Vivo Erin M. Taylor • Robyn Sackeyfio Robert T. Grant
•
Received: 31 January 2014 / Accepted: 2 May 2014 Ó Springer Science+Business Media New York and International Society of Aesthetic Plastic Surgery 2014
Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors at www.springer.com/00266. Silicone breast implants appear clear prior to implantation but frequently cloudy on explantation (Fig. 1). The pathophysiology behind this phenomenon is rarely examined in the literature despite its common presentation. This transformation is observed only in vivo, after the implant has been in the body for a period of time. We examine potential causes of implant cloudiness due to an alteration of implant materials or the introduction of biological materials into the implant and propose a potential mechanism for this phenomenon. Possible factors that may alter the chemical structure of implant materials include heat, ultraviolet radiation, oxidation, and chemical reactions between implant materials. Two silicone implant components, polydimethylsiloxane (PDMS) and residual platinum catalyst, may change in chemical structure and are examined as possible causes of implant cloudiness. Breast implant silicone gel and silicone elastomer shell are composed of primarily PDMS, a polymerized inorganic–organic polymer that increases in viscosity as the – Si–O–Si–O–Si– polymer chain length increases [1, 2]. The
E. M. Taylor (&) R. Sackeyfio R. T. Grant Division of Plastic and Reconstructive Surgery, New YorkPresbyterian Hospital/Columbia University Medical Center (CUMC), Herbert Irving Pavilion Room 5-508, 161 Fort Washington Avenue, New York, NY 10032, USA e-mail: [email protected] R. T. Grant e-mail: [email protected]
PDMS compound is chemically extremely stable, with low thermal conductivity, high thermal stability, and high chemical resistance to alteration by oxygen, ozone, and UV light. The chemical and physical properties of PDMS change little from -100 to ?250 °C, thus advantageously permitting autoclave sterilization of implants [1]. One study examined the molecular structure of explanted breast implants, both the silicone gel and the outer shell, using nuclear magnetic resonance imaging in comparison to nonimplanted controls [3]. No evidence was found of hydrolysis or chemical degradation of the crosslinked silicone matrix compared to that of nonimplanted controls, even with implants as old as 30 years, suggesting the high biodurability of PDMS. Although the chemical structure of PDMS is unchanged, a suspension of the PDMS material in water that diffuses across the silicone shell may cause the cloudy appearance. Two groups have described Poly Implant Prothe`se implants as having a ‘‘milky’’ appearance on explantation [4, 5], which was determined to be a suspension of water and PDMS [6]. Since PDMS is extremely biodurable, a chemical change in the structure of the silicone is unlikely, but the suspension of the material in water or bodily fluid likely contributes to the cloudy appearance of silicone implants. Platinum catalyst hydroxylation is the most popular method for crosslinking PDMS [2]. The type of platinum used to catalyze PDMS crosslinking is platinum metal, Pt(0), which is a nonsoluble, inert substance with little bioreactivity. After its use in the crosslinking process, the platinum catalyst remains as Pt(0) metal nanoparticles in the silicone gel in extremely low quantities of parts per million. Conversely, platinum salts, which are used in anticancer drugs such as cisplatin, are extremely bioreactive, but unlikely to be found in breast implants [7]. Breast
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Aesth Plast Surg Fig. 1 Silicone implant (left) before implantation and (right) after explantation. The cloudiness of a silicone implant evident on explantation is a drastic change from the clear and colorless silicone implant prior to implantation
implants are typically in reducing environments in the body, so oxidation of Pt(0) to the platinum salts Pt(II) and Pt(IV) is an unfavorable reaction and unlikely to occur [7, 8]. Since platinum exists in silicone breast implants in an unreactive state in extremely low quantities, it is unlikely that the platinum species contributes to a change in chemical structure of implant materials. One study showed no difference in the molecular weight distribution of the components between yellow and clear silicone breast implants with molecular analysis of yellow versus clear silicone gel implants [4]. Thus, the molecular components of silicone implants are likely neither altered nor destroyed. The inflow of bodily fluids has been examined as a cause of the cloudy appearance of silicone implants. The silicone elastomer shell is highly permeable to gases and liquids [2], which may allow for the influx of biological fluids. Because breast implants are foreign bodies, they elicit a host response and create a protective capsule to isolate the foreign material. Capsules are typically 0.3–7 mm thick, with a thicker posterior surface than the concave surface [9, 10], and composed of three layers: the inner most layer is saturated with fibroblasts and dendritic cells, the intermediate layer is composed of loose connective tissue with the internal vascular supply, and the outermost layer is composed of dense connective tissue with an external blood supply [11]. Fibrosis replaces the inflammatory reaction, which increases with the age of the implant [12]. Since the silicone elastomer shell is highly permeable to low-molecular-weight liquids, bodily fluid likely diffuses across the membrane. Fluid with inflammatory cells may appear cloudy independent of other factors and lead to the cloudy appearance of implants. Thus, the suspension of PDMS in bodily fluid or water may cause the cloudiness of silicone implants. For implants that remain clear after implantation, this suspension of PDMS in fluid may not occur. In conclusion, we hypothesize that silicone breast implants change from clear to cloudy after implantation
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due to the inflow of bodily fluid into the implant. Since the outer silicone elastomer shell is permeable to liquids, water or bodily fluids may cross this membrane, leading to the suspension of PDMS and the cloudy appearance of silicone implants. Conflicts of interest Dr. Grant is on the Speaker’s Bureau for Allergan and CR Bard/Davol and consults for ITI Technologies. Drs. Taylor and Sackeyfio have no conflicts of interest or financial ties to disclose.
References 1. Daniels AU (2012) Silicone breast implant materials. Swiss Med Wkly 142:w13614 2. Puskas JE, Luebbers MT (2012) Breast implants: the good, the bad and the ugly. Can nanotechnology improve implants? Wiley Interdiscip Rev Nanomed Nanobiotechnol 4(2):153–168 3. Taylor RB, Eldred DE, Kim G, Curtis JM, Brandon HJ, Klykken PC (2008) Assessment of silicone gel breast implant biodurability by NMR and EDS techniques. J Biomed Mater Res A 85(3):684–691 4. Swarts E, Kop AM, Nilasaroya A, Keogh CV, Cooper T (2013) Rupture of Poly Implant Prothe`se silicone breast implants: an implant retrieval study. Plast Reconstr Surg 131(4): 480e–489e 5. Berry MG, Stanek JJ (2012) The PIP mammary prosthesis: a product recall study. J Plast Reconstr Aesthet Surg 65(6):697–704 6. PIP (Poly Implant Prothe`se) breast implants: TGA update (2012) Therapeutic Goods Administration, Australian Government Department of Health. Available at http://www.tga.gov.au/safety/ alerts-device-breast-implants-120104.htm#.U4PhP8JOWUk 7. Brook MA (2006) Platinum in silicone breast implants. Biomaterials 27(17):3274–3286 8. Arepalli SR, Bezabeh S, Brown SL (2002) Allergic reaction to platinum in silicone breast implants. J Long Term Eff Med Implants 12(4):299–306 9. Gayou RM (1979) A histological comparison of contracted and non-contracted capsules around silicone breast implants. Plast Reconstr Surg 63(5):700–707 10. Carpaneda CA (1997) Inflammatory reaction and capsular contracture around smooth silicone implants. Aesthetic Plast Surg 21(2):110–114
Aesth Plast Surg 11. Prantl L, Fichtner-Feigl S, Hofstaedter F, Lenich A, EisenmannKlein M, Schreml S (2008) Flow cytometric analysis of peripheral blood lymphocyte subsets in patients with silicone breast implants. Plast Reconstr Surg 121(1):25–30
12. Bassetto F, Scarpa C, Caccialanza E, Montesco MC, Magnani P (2010) Histological features of periprosthetic mammary capsules: silicone versus polyurethane. Aesthetic Plast Surg 34(4):481–485
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LETTER TO THE EDITOR
BREAST
Clear to Cloudy: Silicone Breast Implants In Vivo Erin M. Taylor • Robyn Sackeyfio Robert T. Grant
•
Received: 31 January 2014 / Accepted: 2 May 2014 Ó Springer Science+Business Media New York and International Society of Aesthetic Plastic Surgery 2014
Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors at www.springer.com/00266. Silicone breast implants appear clear prior to implantation but frequently cloudy on explantation (Fig. 1). The pathophysiology behind this phenomenon is rarely examined in the literature despite its common presentation. This transformation is observed only in vivo, after the implant has been in the body for a period of time. We examine potential causes of implant cloudiness due to an alteration of implant materials or the introduction of biological materials into the implant and propose a potential mechanism for this phenomenon. Possible factors that may alter the chemical structure of implant materials include heat, ultraviolet radiation, oxidation, and chemical reactions between implant materials. Two silicone implant components, polydimethylsiloxane (PDMS) and residual platinum catalyst, may change in chemical structure and are examined as possible causes of implant cloudiness. Breast implant silicone gel and silicone elastomer shell are composed of primarily PDMS, a polymerized inorganic–organic polymer that increases in viscosity as the – Si–O–Si–O–Si– polymer chain length increases [1, 2]. The
E. M. Taylor (&) R. Sackeyfio R. T. Grant Division of Plastic and Reconstructive Surgery, New YorkPresbyterian Hospital/Columbia University Medical Center (CUMC), Herbert Irving Pavilion Room 5-508, 161 Fort Washington Avenue, New York, NY 10032, USA e-mail: [email protected] R. T. Grant e-mail: [email protected]
PDMS compound is chemically extremely stable, with low thermal conductivity, high thermal stability, and high chemical resistance to alteration by oxygen, ozone, and UV light. The chemical and physical properties of PDMS change little from -100 to ?250 °C, thus advantageously permitting autoclave sterilization of implants [1]. One study examined the molecular structure of explanted breast implants, both the silicone gel and the outer shell, using nuclear magnetic resonance imaging in comparison to nonimplanted controls [3]. No evidence was found of hydrolysis or chemical degradation of the crosslinked silicone matrix compared to that of nonimplanted controls, even with implants as old as 30 years, suggesting the high biodurability of PDMS. Although the chemical structure of PDMS is unchanged, a suspension of the PDMS material in water that diffuses across the silicone shell may cause the cloudy appearance. Two groups have described Poly Implant Prothe`se implants as having a ‘‘milky’’ appearance on explantation [4, 5], which was determined to be a suspension of water and PDMS [6]. Since PDMS is extremely biodurable, a chemical change in the structure of the silicone is unlikely, but the suspension of the material in water or bodily fluid likely contributes to the cloudy appearance of silicone implants. Platinum catalyst hydroxylation is the most popular method for crosslinking PDMS [2]. The type of platinum used to catalyze PDMS crosslinking is platinum metal, Pt(0), which is a nonsoluble, inert substance with little bioreactivity. After its use in the crosslinking process, the platinum catalyst remains as Pt(0) metal nanoparticles in the silicone gel in extremely low quantities of parts per million. Conversely, platinum salts, which are used in anticancer drugs such as cisplatin, are extremely bioreactive, but unlikely to be found in breast implants [7]. Breast
123
Aesth Plast Surg Fig. 1 Silicone implant (left) before implantation and (right) after explantation. The cloudiness of a silicone implant evident on explantation is a drastic change from the clear and colorless silicone implant prior to implantation
implants are typically in reducing environments in the body, so oxidation of Pt(0) to the platinum salts Pt(II) and Pt(IV) is an unfavorable reaction and unlikely to occur [7, 8]. Since platinum exists in silicone breast implants in an unreactive state in extremely low quantities, it is unlikely that the platinum species contributes to a change in chemical structure of implant materials. One study showed no difference in the molecular weight distribution of the components between yellow and clear silicone breast implants with molecular analysis of yellow versus clear silicone gel implants [4]. Thus, the molecular components of silicone implants are likely neither altered nor destroyed. The inflow of bodily fluids has been examined as a cause of the cloudy appearance of silicone implants. The silicone elastomer shell is highly permeable to gases and liquids [2], which may allow for the influx of biological fluids. Because breast implants are foreign bodies, they elicit a host response and create a protective capsule to isolate the foreign material. Capsules are typically 0.3–7 mm thick, with a thicker posterior surface than the concave surface [9, 10], and composed of three layers: the inner most layer is saturated with fibroblasts and dendritic cells, the intermediate layer is composed of loose connective tissue with the internal vascular supply, and the outermost layer is composed of dense connective tissue with an external blood supply [11]. Fibrosis replaces the inflammatory reaction, which increases with the age of the implant [12]. Since the silicone elastomer shell is highly permeable to low-molecular-weight liquids, bodily fluid likely diffuses across the membrane. Fluid with inflammatory cells may appear cloudy independent of other factors and lead to the cloudy appearance of implants. Thus, the suspension of PDMS in bodily fluid or water may cause the cloudiness of silicone implants. For implants that remain clear after implantation, this suspension of PDMS in fluid may not occur. In conclusion, we hypothesize that silicone breast implants change from clear to cloudy after implantation
123
due to the inflow of bodily fluid into the implant. Since the outer silicone elastomer shell is permeable to liquids, water or bodily fluids may cross this membrane, leading to the suspension of PDMS and the cloudy appearance of silicone implants. Conflicts of interest Dr. Grant is on the Speaker’s Bureau for Allergan and CR Bard/Davol and consults for ITI Technologies. Drs. Taylor and Sackeyfio have no conflicts of interest or financial ties to disclose.
References 1. Daniels AU (2012) Silicone breast implant materials. Swiss Med Wkly 142:w13614 2. Puskas JE, Luebbers MT (2012) Breast implants: the good, the bad and the ugly. Can nanotechnology improve implants? Wiley Interdiscip Rev Nanomed Nanobiotechnol 4(2):153–168 3. Taylor RB, Eldred DE, Kim G, Curtis JM, Brandon HJ, Klykken PC (2008) Assessment of silicone gel breast implant biodurability by NMR and EDS techniques. J Biomed Mater Res A 85(3):684–691 4. Swarts E, Kop AM, Nilasaroya A, Keogh CV, Cooper T (2013) Rupture of Poly Implant Prothe`se silicone breast implants: an implant retrieval study. Plast Reconstr Surg 131(4): 480e–489e 5. Berry MG, Stanek JJ (2012) The PIP mammary prosthesis: a product recall study. J Plast Reconstr Aesthet Surg 65(6):697–704 6. PIP (Poly Implant Prothe`se) breast implants: TGA update (2012) Therapeutic Goods Administration, Australian Government Department of Health. Available at http://www.tga.gov.au/safety/ alerts-device-breast-implants-120104.htm#.U4PhP8JOWUk 7. Brook MA (2006) Platinum in silicone breast implants. Biomaterials 27(17):3274–3286 8. Arepalli SR, Bezabeh S, Brown SL (2002) Allergic reaction to platinum in silicone breast implants. J Long Term Eff Med Implants 12(4):299–306 9. Gayou RM (1979) A histological comparison of contracted and non-contracted capsules around silicone breast implants. Plast Reconstr Surg 63(5):700–707 10. Carpaneda CA (1997) Inflammatory reaction and capsular contracture around smooth silicone implants. Aesthetic Plast Surg 21(2):110–114
Aesth Plast Surg 11. Prantl L, Fichtner-Feigl S, Hofstaedter F, Lenich A, EisenmannKlein M, Schreml S (2008) Flow cytometric analysis of peripheral blood lymphocyte subsets in patients with silicone breast implants. Plast Reconstr Surg 121(1):25–30
12. Bassetto F, Scarpa C, Caccialanza E, Montesco MC, Magnani P (2010) Histological features of periprosthetic mammary capsules: silicone versus polyurethane. Aesthetic Plast Surg 34(4):481–485
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