The safety and efficacy of breast implants for augmentation mammaplasty

This review of the efficacy and safety of breast implants was intended to focus on our current body of knowledge about these devices. There are informational gaps, but not all of these can be laid at the door of imperfect studies or failed scientific methods. Certain properties of the implants are still unmeasurable, immunologic investigation is still evolving, the cause of wound contraction is inexplicable here or in the burnscar contracture, and the indications for and results of this surgery necessarily are subjective. Still, there are a number of investigative avenues open to us, and our cumulative experience shows no reluctance on the part of plastic surgeons to initiate further studies.     

Capsular contracture in silicone gel and saline-filled breast implants after reconstruction

Comparisons between results with randomly allotted silicone-gel and saline-filled prostheses in breast reconstruction after mastectomy led to the following conclusions. Neither prosthesis type is ideal. Leakage from saline-filled implants occurred in 2 of the 37 implants, with resultant deflation. Silicone prostheses had a significantly higher rate of capsular contracture [surgeon's evaluation: 54 percent capsular contracture for silicone-gel compared with 20 percent for saline-filled prostheses (p = 0.006); patients' evaluation for the same figures: 54 percent compared with 29 percent (p = 0.03)]. Other authors have shown the presence of silicone in the tissue around silicone-gel-filled silicone implants, but less or none around saline-filled silicone implants. Since the only difference between the two groups was the randomly allotted implants, we assume that the free silicone around silicone-gel-filled prostheses is the major cause of capsular contracture. Since the saline-filled implants showed a 20 percent capsular contracture rate, there could be other causes of capsular contracture in this study. For prevention of contracture, improved implant encapsulation and use of a less reactive filling substance seem to offer possibilities. Surgical technique should aim to preserve the integrity of the prosthesis.     

In vivo efficacy of antimicrobe-impregnated saline-filled silicone implants

Bacterial colonization of mammary implants is a prelude to clinical infection and has been implicated in the etiology of capsular contracture. Antimicrobial impregnation of a variety of medical devices with the combination of minocycline and rifampin has recently emerged as a potentially effective method for preventing device colonization and device-related infection. The objective of this animal study was to examine in vivo the antimicrobial efficacy of minocycline/rifampin-impregnated, saline-filled silicone implants. A rabbit model of Staphylococcus aureus colonization and infection of subcutaneously placed implants was used. A total of 48 saline-filled silicone implants (24 antimicrobe-impregnated and 24 control unimpregnated implants) were suspended in a 106 colony-forming units/ml bacterial suspension of S. aureus for 30 minutes at room temperature, allowed to dry for 60 minutes, and then implanted subcutaneously in the back of 12 rabbits (two antimicrobe-impregnated and two control implants were placed in each rabbit). Rabbits were monitored daily, then killed either at 2 weeks (10 rabbits) or at 4 weeks (two rabbits) and cultured. The antimicrobe-impregnated implants were 12 times less likely to be colonized than control unimpregnated implants (two of 24 versus 23 of 24; p < 0.001), and they were a significantly less likely cause of implant-related infection (0 of 24 versus 22 of 24; p < 0.001) and implant-related abscess (0 of 24 versus 21 of 24; p < 0.001) than control implants. The minocycline/rifampin-impregnated implants routinely demonstrated zones of inhibition against S. aureus at the time of explantation. These results indicate that minocycline/rifampin-impregnated implants can significantly decrease the rate of bacterial colonization, implant-related infection, and implant-related abscess. Antimicrobe-impregnated implants also have the potential of reducing the likelihood of capsular contracture.     

Calcification properties of saline-filled breast implants

Three patients requested explantation of their saline-filled breast implants. Bilateral calcification had occurred in all six implants. Four of the implants were manufactured by McGhan Corporation (Santa Barbara, Calif.), and two, by the Simaplast Company (Toulon, France). All implants had been inserted in the subglandular plane and had been in place for 7 to 23 years. At the time of explantation, patients were 32, 34, and 44 years old. Calcification on the surface of the implants and capsules was analyzed. Implant surface calcification was clinically evident on all six implants, appearing as ivory-colored, tenaciously adherent deposits, only on the anterior surface of the implant. Capsular calcification, which was observed only microscopically, was characterized by poorly organized, irregularly shaped, calcified agglomerates; this calcification also occurred only on the anterior surface of the capsule, adjacent to the area of calcification on the implant. Ultrastructural analysis of scrapings from the implant surface showed large, electron-dense aggregates of crystals, with individual crystals measuring approximately 40 x 10 x 10 nm. In contrast, capsular calcification was characterized by two patterns of deposition, spherulitic aggregates of needle-shaped crystals and areas of metaplastic bone. The individual crystals were approximately 40 x 10 x 10 nm. Energy-dispersive x-ray spectroscopy of specimens from the areas of calcification on the implant and capsule surfaces demonstrated calcium and phosphorus. Electron diffraction of crystals from the implant and capsule surfaces demonstrated the D-spacings characteristic of calcium apatite. There were many differences between the calcification properties of these six saline implants and those of silicone gel implants. For example, mineralization has not been observed on the surface of gel implants, but in these saline implants it occurred primarily on the implant surface. Also, capsular calcification has been observed clinically in gel implants across the surface of the capsule (except at the site of attachment of a Dacron patch), but in this study it was observed only microscopically and was located on the anterior surface of the capsule, adjacent to the area of calcification on the implant. In addition, crystals 100 times larger than those observed on the six saline implant capsules have been observed on the surface of gel implant capsules. A model is presented to explain the mechanism of calcification associated with breast implants and to explain the observed differences between saline-filled and gel-filled implants.     

Fungi in and around implants after augmentation mammaplasty

Four cases of possible fungal infections after 700 augmentation mammaplasties are presented in a 9-year experience. The source could not be determined. If any readers have had one or more similar cases, we would appreciate your contacting us.     

Conservation therapy for breast cancer following augmentation mammaplasty

Breast conservation therapy (wide local excision, axillary lymph node dissection, and whole-breast irradiation) is an increasingly popular alternative to mastectomy for breast cancer patients. A sizable (and growing) number of breast cancers occur in women with prior augmentation mammaplasty. Augmented breast cancer patients are currently being treated with conservation therapy, but no study has investigated complications and cosmetic results of radiation therapy specifically in this group of women. Between 1981 and 1988, we used conservation therapy in 17 augmented breast cancer patients. Fifteen patients were available for follow-up. In 10 (67 percent), significant capsular contracture occurred in the irradiated breast an average of 12 weeks following completion of treatment. Four patients have undergone revisionary surgery to correct symptoms arising from contracture. This poor outcome contradicts the results reported in previously published studies. We conclude that irradiation of the breast for cancer in augmented women results in a high incidence of scar-tissue contracture and poor cosmetic results.     

A comparison of conventional and low-bleed implants in augmentation mammaplasty.

We conducted a double-blind, retrospective comparison between low-bleed and non-low-bleed (conventional) mammary implants because no controlled study has shown a difference in the degree of capsular contracture between the two types of implants. Twenty-five patients had conventional implants and form group A; twenty-eight patients had low-bleed implants and form group B. All patients had submuscular augmentation. The mean Baker score was 1.51 for group A and 1.04 for group B for the entire patient population and 1.65 for group A and 1.07 for group B for patients with more than 1 year of follow-up. For the entire population, 34 percent of group A and 3.6 percent of group B had a Baker score of 2 or greater. For the population with more than 1 year of follow-up, 42 percent of group A and 7 percent of group B had a Baker score of 2 or greater. There was significantly (p less than 0.007) less contracture with the low-bleed implants for the entire population as well as for those patients with greater than 1 year of follow-up (p less than 0.015).     

In vivo study of electrolyte exchanges through membranes of saline-filled breast implants

Saline-filled breast implants are currently used in breast reconstruction and augmentation. Free diffusion of electrolytes through these implants has been questioned recently and is of potentially high importance. Many questions are still unanswered about this phenomenon. Eighteen prostheses were reviewed and tested for diffusion and exchange of electrolytes and glucose in vivo. None of these implants demonstrated major variation of the inner contents from the original saline used to fill them, emphasizing the real innocuousness of such implants in terms of possible ionic pooling. Extrapolation of these results to all implants made by different manufacturers is not possible according to the sample size in the present study.     

Women's psychosocial outcomes of breast augmentation with silicone gel-filled implants: a 2-year prospective study

This study examined the experiences of 360 women receiving bilateral breast augmentation with Dow Corning's Silastic MSI (textured) or Silastic II (smooth) gel-filled mammary implants. Before surgery, the women completed a quantitative assessment of their surgical expectations and concerns. At 6, 12, and 24 months postoperatively, they rated their satisfaction with surgery and its specific psychosocial outcomes, their concerns, and benefits-to-risks appraisals of the augmentation. The women reported very high levels of satisfaction with the procedure and its psychosocial outcomes, which did not change over time. Throughout the 2-year period, over 90 percent of the women were satisfied with surgery and their resultant body-image changes. Their concerns about risks, reported by 19 percent before surgery, declined after surgery and remained subsequently stable. Most participants (75 to 85 percent) reported that the benefits of surgery exceeded its risks. Postoperative events such as significant capsular contracture that compromised aesthetic results diminished aspects of satisfaction, whereas less obvious events did not. Systematic analysis of attrition (i.e., missing assessments) did not indicate any biases because of complications or psychosocial outcomes. Evaluation of a possible impact of the publicity surrounding the Food and Drug Administration's voluntary moratorium on the use of silicone gel-filled breast implants, which occurred during the study, revealed a limited effect, if any, on women's psychosocial outcomes. Findings are discussed in relation to the study's methodological strengths and limitations and with respect to the broader context of patient care.     

Immunopathologic effects of silicone breast implants.

Silicone-gel breast implants have been associated with a myriad of autoimmune and connective tissue disorders by anecdotal reports and small observational series. To date, no prospective epidemiologic studies have been done to substantiate these observations, but an increasing body of literature is being developed and older studies are being recognized that point to immunotoxic or inflammatory effects of these breast implant components. The development of disease due to implants would depend on the interaction of genetic host factors so that only a few patients would potentially be at risk. Based on the example of other chemically mediated disorders, such as scleroderma in association with silica exposure, latency periods of more than 30 years before disease develops may be possible. Herein we review studies on silicone and immunity.