A clinical comparison of the tendency to capsular contracture between smooth and textured gel-filled silicone mammary implants.

The aim of this prospective, controlled clinical investigation was to find out if there is a difference in the capsular contracture rate between silicone implants with a smooth or textured surface as the only difference. Twenty-five women with bilateral mammary hypoplasia underwent mammary augmentation. All got a textured implant on one side and a smooth implant on the other. The implants were placed subglandularly. Follow-up examinations were done on six occasions. Three parameters were used for estimation of the tendency to capsular contracture: (1) the patient's opinion on differences in hardness of the breasts, (2) the investigator's classification of capsular contracture, and (3) applanation tonometry. At the end of the follow-up period, after 1 year, all parameters showed with no doubt that the breasts augmented with textured implants had a lower tendency to develop contracting capsules than the breasts augmented with smooth implants.     

Recurrence of subglandular breast implant capsular contracture: anterior versus total capsulectomy

The objective of this study was to determine whether the type of capsulectomy, anterior or total, affects the recurrence of capsular contracture around subglandular silicone-gel breast implants. A retrospective analysis was performed of patients who underwent either anterior or total capsulectomy for Baker grade 3 or 4 subglandular capsular contracture in our unit. All patients were invited to a review clinic where their capsular status was assessed. There were 100 anterior- disc capsulectomies in 60 patients between 1988 and 1997 and 99 total capsulectomies in 60 patients between 1990 and 1998. The follow-up in the former group was a median of 7 years and mean 6.9 years, compared with median 2.5 and mean 3.1 years in the latter group. Eighty-six percent of the implants removed from both groups at capsulectomy were smooth-walled gel-filled implants. Sixty-nine breasts in the anterior group received textured gel implants at capsulectomy; the remaining 31 received polyurethane-coated Meme implants. In the total capsulectomy group, all but two breasts (one patient) received textured gel implants. After review, the capsular status was known in 80 percent of the anterior and 92 percent of the total capsulectomy group. The review clinic found eight new contractures in five patients to have developed in the anterior compared with none in the total group. Recurrent contractures affected 50 percent of patients (46 percent of breasts) in the anterior and 11 percent of patients (10 percent of breasts) in the total capsulectomy group. Kaplan-Meier survival analysis was applied to the data. By including only patients who received textured gel implants at capsulectomy, the Logrank found a statistical difference between the two treatment groups (0.01 < p < 0.5). We believe that this study provides some evidence that total capsulectomy for subglandular silicone breast implant capsular contracture results in a lower capsular recurrence than anterior- disc capsulectomy. The pattern and risk of recurrence after total capsulectomy and exchange for a modern textured prosthesis appear to approach those following primary augmentation.     

Capsular contracture around saline-filled fine textured and smooth mammary implants: a prospective 7.5-year follow-up.

In a previous prospective randomized clinical study comparing in the same patient textured and smooth saline-filled mammary implants (Biocell) with large pore size (300 to 600 microm), we saw no difference in capsular contracture. This study was undertaken in a similar way to compare capsular contracture around smooth and textured saline-filled prostheses with pores of small size. During a period of 7.5 years, the breast hardness was followed up, and at the end of the study patient satisfaction was evaluated.Twenty healthy women with a mean age of 30 years were operated on for breast augmentation. Two surgeons performed all operations in a standardized way. Each patient received subglandularly a Siltex textured saline-filled prosthesis with a pore size of 30 to 70 microm in one breast, and a smooth saline-filled prosthesis in the other. The hardness of the breasts was evaluated after 0.5, 1, and 7.5 years using Baker grading and applanation tonometry. Eighteen patients completed 1-year and 7.5-year follow-up. Two breasts with smooth prostheses were contracted after 6 months (Baker III or IV). After 1 year, four patients with smooth prostheses and one with a textured prosthesis had capsular contracture (p = 0.34). Seven and one-half years after surgery, six patents with smooth and four with textured implants had contracture (p = 0.66). On two patients with smooth prostheses and one patient with a textured prosthesis, the capsule around the implant hardened between 6 and 12 months. Between 1 year and 7.5 years, three breasts with smooth and textured implants contracted and one with a textured implant softened.The patients reported on a Visual Analogue Scale (1 to 10) the impact of the augmentation on their quality of life to be 9 +/- 1. Four patients preferred the breast with the smooth prosthesis, three preferred the breast with the textured prosthesis, and the others found both breasts equal. This study showed no significant difference of contracture with smooth versus fine textured implants. The majority of the patients preferred the smooth implants. The patients reported that the breast augmentation had had an extremely high impact on their quality of life.     

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.     

Acceleration of capsule formation around silicone implants by infection in a guinea pig model

Fibrous capsules surrounding silicone implants were investigated in a new guinea pig model to delineate some of the factors leading to capsular contracture. Both the implant surfaces and tissue capsules were examined by light and scanning transmission electron microscopy (STEM + SEM) with x-ray energy spectroscopy (XES). The capsular tissues were qualitatively similar to those recovered clinically, showing dense parallel collagen deposits, fibroblasts, myofibroblasts, macrophages, and foreign-body giant cells. Silicone was positively identified within intercellular vacuoles and the rough endoplasmic reticulum of macrophages by XES. Tissue recovered from the capsules that surrounded implants that were contaminated with S. aureus presented a qualitatively similar histologic spectrum. The contaminated specimens did show an accelerated response. SEM showed a cellular invasion of the silicone envelopes. We conclude that the model accurately simulates the clinical situation and suggests that immune mechanisms may play a key role in capsular contracture.     

The effectiveness of sodium 2-mercaptoethane sulfonate (mesna) in reducing capsular formation around implants in a rabbit model

The development of capsular contracture is the most common complication associated with the insertion of breast implants. The authors studied the role of sodium 2-mercaptoethane sulfonate (mesna) in reduction of capsular formation in a rabbit model. Two 40-cc textured saline implants were placed dorsally into each of the 20 rabbits in the study. At the time of insertion of the implants, 10 ml of a 10% solution of mesna was instilled into one of the pockets and normal saline was instilled into the other. The implants were removed and a capsulectomy was performed at 5 months. The capsules were examined histologically for qualitative differences between the two groups. Quantitative analysis of the thickness of the capsule and the myofibroblast populations was also performed and compared between the two groups. The mean total thickness of the capsule around the implants was 496.8 microm in the mesna-treated group compared with 973.7 microm in the saline-treated group (p < 0.001). Likewise, the thickness of the myofibroblast layer was reduced in the mesna-treated group at 283.2 microm versus 555 microm in the saline-treated group (p < 0.0001). The capsules were also relatively less vascular in the mesna-treated group. Because of its ability to reduce the extent of capsular formation and to diminish development of myofibroblasts in the capsules, mesna would appear to be a useful adjunct in the prevention of capsular contracture formation.     

Prospective evaluation of late cosmetic results following breast reconstruction: I. Implant reconstruction

The long-term cosmetic outcome of breast implant reconstruction is unknown. The morbidity and cosmetic outcome of 360 patients who underwent immediate postmastectomy breast reconstruction with various types of implants have been analyzed prospectively over a 9-year period. Of these patients, 334 who completed their reconstruction were suitable for evaluation of their cosmetic outcome. The early complication rate (< 2 months) was 9.2 percent, with an explantation rate of 1.7 percent. The late complication rate (> 2 months) was 23 percent, with a pathological capsular contracture rate of 11 percent at 2 years and 15 percent at 5 years and an implant removal rate of 7 percent. The revisional surgery rate was 30.2 percent.The cosmetic results were assessed prospectively using an objective five-point global scale. Every patient was scored at each visit once surgery was completed. The overall cosmetic outcome deteriorated in a linear fashion, from an initial acceptable result of 86 percent 2 years after patients completed their reconstruction to only 54 percent at 5 years. This decline in cosmetic outcome was not associated with the type of implant used, the volume of the implant, the age of the patient, or the type of mastectomy incision employed. Radiotherapy was not a significant factor because only 28 patients were irradiated. Upon Cox model analysis, pathological capsular contracture was the only factor that contributed significantly to a poor cosmetic outcome in which p < 0.0001 (relative risk 6.3). Despite a high revisional surgery rate, deterioration still occurred, suggesting that other unaccounted for variables were responsible. On photographic retrospective review of the patients without capsular contracture who demonstrated deterioration in their cosmetic scores, it became clear that a possible reason for their poor results was late asymmetry produced by the failure of both breasts to undergo symmetrical ptosis with aging.     

Use of stacked polyurethane-covered mammary implants in aesthetic and reconstructive breast surgery

The use of stacked polyurethane-covered mammary implants has proven useful in improving results in the correction of deficiencies of mammary form and projection that can occur in certain cases of congenital and acquired breast deformity. The method has been used in 57 patients (102 breasts). The rate of significant complications, including seroma, rash, infection, hematoma, and capsular contracture, has been low (1 to 6 percent). Polyurethane-covered implants will maintain their position when used in a stacked system because of their unique biophysical characteristics, which include tissue bonding and a high friction coefficient between the implant surfaces.     

Methyl prednisolone in double-lumen gel-saline submuscular mammary prostheses: a double-blind, prospective, controlled clinical trial

At the time of immediate breast reconstruction with submuscular implants, 76 consecutive patients (89 breasts) were randomized into two groups. One received a gel-saline, double-lumen implant with 40 cc of saline added to the outer lumen, while the other received the same implant plus 40 cc of saline and 16 mg methyl prednisolone (40 mg%). Patients were followed for a minimum of 3 years. The groups, which were matched for patient age and implant size, were evaluated at 3, 12, 24, and 36 months for capsular contracture, steroid atrophy, and other complications. With completion of the double-blind study, the patients with submuscular gel-saline implants with only saline added had an overall capsular contracture rate of 38 percent at 3 months, 38 percent at 12 months, and 44 percent at 24 and 36 months. Those with methyl prednisolone had an overall capsular contracture rate of 14 percent at 3 months, and this remained unchanged through the end of the study. The rates of all other complications were comparable. Methyl prednisolone in a dose of 16 mg in 40 cc saline (concentration 40 mg%), when used in the outer lumen of a double-lumen gel-saline implant in a submuscular pocket, is both safe and efficacious in reducing the risk of capsular contracture for a minimum of 3 years in patients undergoing immediate breast reconstruction with submuscular mammary implants.     

Effects of a topical essential oil-containing formulation on biofilm-forming coagulase-negative staphylococci

AIMS: To evaluate the antimicrobial effects of Polytoxinol (PT), a topical essential oil-based formulation, against biofilm positive strains of coagulase-negative staphylococci. METHODS AND RESULTS: Using a microtitre plate assay we measured inhibitory effects for PT against a selection of biofilm-forming clinical isolates of coagulase-negative staphylococci. Susceptibility varied considerably (MIC = 0.6-20 000 ppm). For the most tolerant clinical isolate (Staphylococcus warneri) biofilm growth was inhibited by a 32-fold lower PT concentration than planktonic growth. This inhibition of biofilm development, which was not observed with the other test isolates, was related to an inhibition of the initial phase of S. warneri cell adherence to the polystyrene surface. CONCLUSION: The antimicrobial efficacy of PT was verified against clinical isolates of coagulase-negative staphylococci in vitro. PT was able to inhibit biofilm formation in the most tolerant isolate at sub-inhibitory concentrations. SIGNIFICANCE AND IMPACT OF THE STUDY: These observations indicate that an ability to prevent biofilm formation, independently of effects on cell viability may contribute to the in vivo topical efficacy of essential oils.     

Intracapsular allogenic dermal grafts for breast implant-related problems

Despite advances in surgical techniques and breast implant design, certain problems unique to breast implant surgery remain. The historically most onerous problem, capsular contracture, is relatively uncommon now. However, problems related to thin capsules and periprosthetic atrophy are becoming more common; these problems include rippling, symmastia, implant malposition, and bottoming out. Options for treatment of these conditions remain extremely limited, particularly with saline implants. Allogenic dermal grafting provides one satisfactory option. Techniques for use of allogenic dermal grafts and early results from 10 patients are summarized in this article, along with histologic analysis confirming viability of the grafts at 6-month follow-up in one patient. No graft-related complications were identified.     

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.     

Matrix metalloproteinases, tissue inhibitors of metalloproteinases, aminoterminal propeptide of procollagen type III, and hyaluronan in sera and tissue of patients with capsular contracture after augmentation with Trilucent breast implants

In various fibrotic diseases, matrix metalloproteinases (MMPs) and their natural inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), play an important role. In our study, serum concentrations of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 were determined by enzyme-linked immunosorbent assay in 17 female patients with Baker grade II (n =9), III (n =7), and IV (n =1) capsular contracture after bilateral cosmetic mamma augmentation with Trilucent implants (AEI, Inc., Caversham, United Kingdom). Samples of capsular tissue for standard histology and immunohistochemistry were obtained from all patients. Sera from 20 female patients who had plastic surgery for reduction mammaplasty were used as the control group. The aminoterminal propeptide of procollagen type III (PIIINP) and hyaluronan were analyzed as markers for fibrogenesis in both groups, too. Statistical analysis was performed using the Mann-Whitney test and Spearman rank correlation. Patients with capsular contracture presented significantly higher concentrations of TIMP-1 and TIMP-2 in their sera than did the control group (p < 0.05), which correlated with Baker grade (r = 0.7 versus r = 0.65; p < 0.05). The concentration of MMP-2 was significantly higher in the sera of patients with capsule fibrosis, whereas there were no significant differences in MMP-1, MMP-9, and PIIINP serum concentrations. Patients with capsule fibrosis had a significantly lower MMP-to-TIMP ratio (1.1 +/- 0.4, p <0.05) than the control group (1.5 +/- 0.4), which correlated with the Baker classification (r =0.7; p <0.05). The hyaluronan serum concentration of patients with capsular contracture was significantly higher (p < 0.05) and correlated with the Baker grade (r = 0.73; p < 0.05), whereas PIIINP showed no difference. In the histologic evaluation, there was a chronic inflammatory reaction in the capsules around the breast implants and refracting material within the substance. Immunohistochemically, TIMP-1 and TIMP-2 showed an intensive accumulation, and MMP-2 showed a local reaction. PIIINP could be detected, too, whereas there was no staining for MMP-1 and MMP-9.The elevated systemic MMP-2 concentration and the local positive staining in the tissue might be due to the chronic inflammatory reaction. Nevertheless, the balance between MMPs and their natural inhibitors is disturbed in patients with capsule contracture. The elevated systemic concentration of TIMPs might be a pathway in the pathogenesis of severe fibrosis after breast augmentation with alloplastic material. Hyaluronan might be a useful marker for early prediction of capsule fibrosis, whereas PIIINP is not useful as a predictor.     

Breast reconstruction using tissue expanders and implants in Hodgkin's patients with prior mantle irradiation.

Women treated for Hodgkin's disease with mantle irradiation have an increased risk for developing breast cancer. Typically, breast malignancy in Hodgkin's patients presents bilaterally in a younger age group. Skin flap ischemia, poor skin expansion, implant extrusion, capsular contracture, and poor cosmesis are common sequelae of tissue expander/implant breast reconstruction after breast irradiation for failed breast conservation therapy. This has led most surgeons to favor autologous tissue reconstruction in this setting. This study was performed to determine the efficacy of tissue expander/implant breast reconstruction in breast cancer patients who have been treated with prior mantle irradiation for Hodgkin's disease. A retrospective analysis of all breast cancer patients with a history of Hodgkin's disease and mantle irradiation treated with mastectomy and tissue expander/implant reconstruction between 1992 and 1999 was performed. There were seven patients, with a mean age of 35 years (range, 28 to 42 years). The average interval between mantle irradiation and breast cancer diagnosis was 16 years (range, 12 to 23 years). All patients underwent two-stage reconstruction. Textured surface tissue expanders were placed in a complete submuscular position at the time of mastectomy. Expansion was initiated 2 weeks after insertion and continued on a weekly basis until completion. Expanders were replaced with textured surface saline-filled implants as a second stage. Patients were evaluated for skin flap ischemia, infection, quality of skin expansion, implant extrusion, capsular contracture, rippling, symmetry, and final aesthetic outcome. Breast cancer was bilateral in five patients and unilateral in two. Two patients did not undergo simultaneous bilateral breast reconstruction because of metachronous cancer development. One of the patients had an initial transverse rectus abdominis muscle flap breast reconstruction, followed by a tissue expander/implant reconstruction of the opposite breast. The average follow-up was 3 years. Complications were limited to one case of cellulitis after implant placement that resolved with intravenous antibiotics. There were no cases of skin flap ischemia, poor skin expansion, or implant extrusion. Overall patient satisfaction was high and revisions were not requested or required. Symmetry was best achieved with bilateral implants. This study demonstrates the efficacy of tissue expander/implant breast reconstruction in patients treated with prior mantle irradiation. In this series, tissue expansion was reliable with low morbidity. Second-stage placement of permanent implants yielded good aesthetic results without significant capsular contracture. Mantle irradiation did not appear to compromise the prosthetic breast reconstruction. Tissue expander/implant breast reconstruction should remain a viable option in this category of irradiated patients.     

Long-term use of polyurethane breast prostheses: a 14-year experience

I have used polyurethane prostheses for the past 14 years, implanting 220 implants into 130 patients who desired breast reconstruction after subcutaneous mastectomy or cancer ablation or simply breast augmentation. I theorize that a polyurethane-covered implant resists contracture, retaining its compressibility because the fibroblasts proliferate into the polyurethane in many different directions. When the fibrils contract, the forces of contracture counterbalance one another, resisting contracture. However, when smooth prostheses are implanted, fibrils are directed in a circular fashion around the implant and naturally contract, leading to firmer breasts. There were 115 prostheses inserted following subcutaneous mastectomy, and 22 percent developed contracted capsules. Seven implants became exposed because of skin necroses; one was removed because of a Staphylococcus infection; and two patients developed a combination of polyurethane and silicone granulomas. These developed only with the earlier implant, where there was shedding of the polyurethane sponge layer and silicone bled from the low-viscosity silicone used in the earlier implants. No granulomas were noted with the currently used Surgitek Replicon implant. Eighty-five breasts were reconstructed after cancer ablation with polyurethane implants, and the contracture rate was 2.3 percent. Other complications were minimal. A smaller group of patients had augmentation mammaplasty, and 20 prostheses were placed in 10 patients. A 15 percent contracture rate was noted in this group. In this study, 82 percent of patients were followed for up to 14 years. Capsular contractures occurred in 30 implants between 1 and 11 years, for an average recurrence at 6.3 years. The overall contracture rate was 13 percent. Other complications were minimal. All implants were placed subcutaneously or subglandularly, and all were drained.     

Silicone gel-filled breast implant integrity: a retrospective review of 478 consecutively explanted implants

Concern has been expressed over the long-term integrity of silicone gel breast implants. There are no large series representing experience with these implants outside of the United States. A retrospective case note review of explanted silicone breast implants was performed; 478 implants have been explanted during the past 11 years and relate to the use of these devices since 1971. Loss of implant integrity was not simply related to its age in vivo. Failure was more likely with implants of the late 1970s and early 1980s (second generation) and with subpectoral placement. Implant failure was independent of capsular contracture as the indication for removal (p = 0.09). There is no evidence that the currently used textured silicone gel breast implants are subject to the same loss of integrity as previous examples of these devices. The life span of these implants, the first of which are approaching 10 years in vivo, is at present unknown. Information concerning the integrity of silicone gel breast implants is essential in the current climate for counseling of both new and old implant recipients.     

Polyurethane foam-covered implants and capsular contracture: a laboratory investigation

Experiments were conducted in rabbits comparing polyurethane foam-covered implants with otherwise identical smooth silicone gel implants. Using five objective methods of measurement of capsular contracture, no significant difference could be identified. The foam-covered implants consistently developed capsular contracture, although in most cases this was of mild degree and would not have been clinically significant. In the two foam-covered implants with hard contractures, there was no evidence of hematoma or separation of the foam.     

Noninvasive assessment of implant capsules

The assessment of implant capsular contracture has been imprecise and vulnerable to observer bias. Attempts to measure capsules with instruments that measure implant deformability are influenced by surrounding breast tissue, subcutaneous fat, and skin. Xeromammography, B-mode ultrasound, and CT were employed in an effort to provide a noninvasive and accurate method of capsule assessment. Through two study phases, implants were placed bilaterally in a total of 21 rabbits. At 4 months, animals underwent radiologic assessment and were then sacrificed for direct implant capsule measurements. Mammographic measurements, more than ultrasound-derived measurements, strongly correlated with laboratory measures of capsular dimensions and deformability. Cross-table lateral mammographic views were more informative than traditional views, providing measures of diameter and height that both strongly correlated with laboratory measurements. CT is theoretically the most accurate method to assess contracture, but it is impractical because of expense and time requirements. The results indicate that radiologic assessment, in particular by xeromammography, of implant capsules is accurate, practical, and noninvasive. Mammography strongly correlates with laboratory measures of implant capsular contracture and therefore could be used in the clinical setting to assess capsular contracture.     

Reconstruction of the breast using polyurethane-coated prostheses

We have inserted 302 Natural-Y polyurethane-coated implants in 92 patients. Follow-up time for the cases studied ranges from 6 months to 41/2 years after reconstruction. None of our patients was observed to develop capsular contracture, and the foreign-body reaction to the polyurethane was of no clinical significance when the implants were placed in a total muscle pocket. Four cases of ruptured prostheses were observed. Overall, the excellent aesthetic results of the polyurethane-coated prostheses were encouraging, resulting in soft, natural-feeling, and aesthetically pleasing breasts.     

Measurement of capsular contracture: the conventional breast implant and the Pittsburgh implant

At present, there is no accurate, reliable method of experimentally measuring capsular contracture. This study had four goals: (1) to define the parameters of capsular contracture employing principles of biomechanics of soft tissues, (2) to develop laboratory techniques to measure the parameters, (3) to design an implant that mechanically impedes the process of encapsulation, and, (4) to test this implant against a conventional one. We have developed a breast implant (the Pittsburgh implant) with an altered surface topography. Its silicone shell is punctuated by projections 1 mm in height and 1 mm in diameter. Two techniques were devised to measure contracture. The first involved measuring the force deformation along a coronal axis. The second involved measuring hydrostatic pressures within the implant resulting from the injection of known quantities of saline. Measurements were performed in vivo on 36 animals. By both force and pressure measurements, the Pittsburgh implant showed less capsular contracture (p = 0.12 and 0.012, respectively). Histology revealed that the prototype surface alters the linear arrangement of myofibroblasts and redirects the laminar collagen into a waveform pattern. We conclude from this experimental study that an altered surface topography may serve as a means of rendering a capsule less mechanically effective. We feel that the proposed methods can be used in the laboratory to characterize the extent of capsular contracture.