Ten-Year Review of a Prospective Randomized Controlled Trial of Textured versus Smooth Subglandular Silicone Gel Breast Implants

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1 Ten-Year Review of a Prospective Randomized Controlled Trial of Textured versus Smooth Subglandular Silicone Gel Breast Implants Nicholas Collis, B.Sc., F.R.C.S.(Ed.), David Coleman, M.S., F.R.C.S.(Plast.), Ivan T. H. Foo, F.R.C.S.(Plast.), and David T. Sharpe, O.B.E., M.A., F.R.C.S. West Yorkshire, England Although textured silicone breast implants have been shown to reduce the incidence of capsular contracture, there is little evidence if this effect is maintained in the long term. It has been 10 years since the double-blind randomized trial in which 53 patients received either Mentor smooth (26) or textured silicone gel implants (27). Of the 14 patients who were not known to have developed a contracture in the smooth group, 11 were reviewed. Three had bilateral contractures. In the textured group, 18 of the 24 patients not known to have contractures were reviewed. None had developed contractures. At 10 years, the incidence of capsular contracture was 65 percent of patients with smooth implants (an increase of 6 percent on the 3-year results) and 11 percent for the textured implant patients (no change on the 3-year results). A database containing the details of 1100 patients reinforces these results by examining the differences in contracture rates of textured, smooth, and polyurethanecoated implants. The effect of submuscular placement on reducing contracture rates regardless of texturing is discussed, as is the apparent increase in capsular contracture in patients who smoke. (Plast. Reconstr. Surg. 106: 786, 2000.) Regardless of the debate concerning the safety of silicone and long-term integrity of silicone breast implants, capsular contracture remains the main drawback to the use of these devices. Submuscular placement is a wellestablished method of reducing the contracture rate, a practice commonplace in the United States, where saline-filled implants have been used since the moratorium on silicone gel-filled implants in The introduction of implant surface texturing in the late 1980s greatly reduced the contracture rate around subglandular implants. 4 6 The causes of capsular contracture and the mechanism of action of texturing in reducing its incidence are still not clear. Although the majority of contractures occur in the short term, allowing short follow-up prospective studies to demonstrate the effect of surface texturing, no studies have shown if this effect is maintained in the long term. We therefore present the 10-year follow-up results of a prospective, randomized, doubleblind, controlled trial of textured versus smooth subglandular silicone gel breast implants. The 1-year and 3-year review results have previously been reported. 5,6 A detailed database provided more evidence for the effect of implant texturing, the development of capsular contracture in other smooth and polyurethane foam coated implants, and the effect of subpectoral implant placement in reducing capsular contracture rates. PATIENTS AND METHODS In 1989, 53 patients for subglandular cosmetic breast augmentation were randomized (double blind) to receive either bilateral smooth or textured silicone gel breast implants (Mentor Medical Systems). Trial protocols have previously been published. The patients were invited by letter to attend a special review clinic. They were rewarded with a small gratuity of 10 for their cooperation. The senior author, unaware of the im- From the Department of Plastic Surgery at Bradford Royal Infirmary and the Plastic Surgery and Burns Research Unit at the University of Bradford. Received for publication August 9, 1999; revised December 9, Presented at the 12th Congress of the International Confederation for Plastic, Reconstructive and Aesthetic Surgery in San Francisco, California, in July of

2 Vol. 106, No. 4 / TEXTURED VERSUS SMOOTH GEL BREAST IMPLANTS 787 plant type, assessed the degree of capsular contracture using the Baker scale. The patients were grouped into either Baker grades 1 and 2 (none and mild) or 3 and 4 (moderate and severe). A database containing the records of all breast implant patients since 1986 (1100 patients) provided information on development of capsular contracture around subglandular textured Mentor implants used subsequent to the trial, smooth Nagor, and polyurethanecoated Même implants. Data concerning the effect of subpectoral placement on capsular contracture for both smooth and textured implants were also available. We acknowledge that the figures from the database are derived from a population that is not wholly under review. The figures for capsular contracture will therefore be an underestimate. Capsular contracture rates were calculated according to the number of affected patients rather than breasts. We believe that capsular contracture is a patient rather than breastbased phenomenon. Statistical analysis was performed using the chi-square test, using the Yates continuity correction where appropriate, and Kaplan Meier survival analysis. RESULTS The average age of the trial patients in 1989 was 30 years with a range of 21 to 44 and SD of 5 years. Of the initial 53 patients entered into the trial, 40 were still available for review after 10 years (overall 75 percent). Figure 1 shows that 38 patients (24 textured, 14 smooth) were not known to have developed capsular contracture. Eighteen of the 24 textured implant patients (75 percent) were reviewed, and none had developed capsular contracture. Eleven of the 14 smooth implant patients (79 percent) were reviewed. Three had developed bilateral contractures since the 3-year review. The outcome in terms of capsular contracture is therefore not known in 3 of the 26 smooth implant patients (12 percent) and 6 of the 27 textured implant patients (22 percent). The 10-year contracture rate calculated strictly according only to those patients reviewed is therefore 65 percent (15 of 23) for smooth implants and 14 percent (3 of 21) for the textured implants. However, extrapolating the results of those who were reviewed to those who were not keeps the smooth implant contracture rate at 65 percent (17 of 26) and lowers the textured implant rate to 11 percent (3 of 27). This is the FIG. 1. The 10-year outcomes of textured versus smooth implants. same as the 3-year review figures, as no new contractures have developed in the textured implant group. The results are significant whichever figures are used (p 0.001). Three of the 15 contractures in the smooth implant group were unilateral (20 percent) and have little impact on the contracture rates or the significance of the results. Fifteen of the 53 patients were already known to have developed capsular contracture (3 unilateral and 12 bilateral) before the 10- year review. Twelve patients had bilateral and one had unilateral anterior disc capsulectomies and exchange for new implants (Siltex gel, eight; Siltex saline, one; and Même polyurethane, four); one patient subsequently had the implants removed. Two (one unilateral and one bilateral) had failed to attend for surgery and further follow-up. Eleven of these capsulectomy patients were reviewed, of whom 45 percent (5 of 11) had developed recurrent Baker grade 3 or 4 capsular contracture (one unilateral and four bilateral). Recurrence was independent of the implant type used during the revisional surgery (three textured Mentor, two Même polyurethane). Figure 2 shows the Kaplan Meier survival analysis for the development of capsular contracture for the trial group. The ability of the

3 788 PLASTIC AND RECONSTRUCTIVE SURGERY, September 2000 TABLE I Incidence of Bilateral Contracture for Different Implant Types Implant Type Capsular Rate: Patients Bilateral Capsules Mentor (smooth) 65 (15/23) 80 (12/15) Nagor (smooth) 48 (28/58) 83 (19/23) Même (textured, polyurethane) 25 (14/57) 67 (8/12) Mentor (textured) 5 (19/364) 53 (9/17) FIG. 2. Smooth versus textured implant 10-year development of subglandular capsular contracture, Kaplan Meier analysis. textured implants to retard capsular development over a 10-year period is clearly seen. It is acknowledged that the lower curve depicting textured contractures is based only on three patients. However, in our unit, 700 subglandular breast augmentations were performed between 1989 and 1997 inclusively using the same textured Mentor implant (336 bilateral, 28 unilateral). To date, 19 patients (5.2 percent overall) are known to have developed capsular contracture, occurring up to 6 years after implantation, of whom 68 percent had experienced contracture within the first 2 years, as with the smooth implants (65 percent) in the trial. The trends set in Figure 2 are probably therefore reliable. Nagor smooth silicone gel implants were used routinely between 1986 and In total, 106 subglandular implants were used in 58 patients (48 bilateral, 10 unilateral) with an incidence of capsular contracture of 48 percent of patients to date (49 percent of breasts). Again, 57 percent of capsules occurred within the 2 years, with the remainder gradually over the following 10 years. Même polyurethane implants were used before their withdrawal in In total, 107 subglandular implants were used in 57 patients (50 bilateral, 7 unilateral) with capsular contracture involving 25 percent of patients (21 percent of breasts) to date. The Même implants appeared to have a low incidence of contracture (about 10 percent) for the first 4 years followed by a steady rise to 25 percent at 10 years. Loss of the polyurethane coating probably accounts for this change. The effect of implant surface type on subsequent capsule development is perhaps further highlighted by the relationship in Table I between the incidence of contracture, determined by the implant type, and whether one or both breasts are affected. The higher the incidence of capsular contracture, the more likely that both breasts will be affected. Subpectoral placement is known to reduce capsular contracture. Of 33 bilateral subpectoral Nagor smooth implants, only 6 percent of patients and 3 percent of breasts (two unilateral contractures) are known to have developed capsular contracture. None of the 24 bilateral subpectoral textured Mentor implants has developed capsular contractures to date. Subpectoral placement has a marked effect reducing capsular contracture rates and appears to be independent of surface texturing (p 0.5). The effect of smoking, common among implant recipients, 7 has not been implicated in the development of capsular contracture. Regarding the distribution of patients who developed capsular contracture between the smokers and nonsmokers for the 365 patients who received 700 subglandular textured Mentor implants, the incidence of capsular contracture for smokers and nonsmokers was 7.7 percent (14 of 181) and 3.0 percent (5 of 165), respectively (0.1 p 0.05). This perhaps deserves further study. DISCUSSION This prospective, controlled trial not only reaffirms the beneficial effect of surface textured silicone breast implants in reducing the incidence of subglandular capsular contracture compared with otherwise identical smooth-surfaced implants, it reaffirms that this effect is maintained in the ensuing years after implantation. We are very fortunate that 75 percent of the trial patients were still available and willing to be reviewed (for the third time). The magnitude of the reduction, 65 percent to 11 percent, has major implications in terms of patient satisfaction, the morbidity associated

4 Vol. 106, No. 4 / TEXTURED VERSUS SMOOTH GEL BREAST IMPLANTS 789 with surgery for capsular contracture, and risk of its subsequent recurrence. In our series, 42 percent of patients developed a recurrent contracture after anterior disk capsulectomy, despite exchange for implants with a lower incidence of contracture. We now perform total capsulectomies to reduce the recurrence of contracture, and this is the subject of a separate article. It would appear that some patients are more susceptible to development of capsular contracture, particularly once they have embarked down that path. Results suggest that prevention is certainly better than cure. The development of capsular contracture is clearly more common in the first 2 years after subglandular implantation, regardless of the implant type, with the exception of the Même polyurethane-coated implants. For the Mentor and Nagor implants, between 57 percent and 68 percent of contractures occurred in the first 2 years compared with 27 percent for the Même prostheses. However, after 4 years, the latter appeared to lose their protection, resulting in a climbing contracture rate from 10 to 25 percent of patients. We found a similar trend in capsular contracture when using Même implants for breast reconstruction. Loss of the protective polyurethane coating has been reported and is probably responsible for this change. 8 This is largely of historical interest now. The Même implants were withdrawn in 1991 because of a theoretical carcinogenic risk (1 in a million) from chemical breakdown of the polyurethane foam to the carcinogen 2-toluene diamine. The large difference in contracture rates between textured and smooth implants in the subglandular position appears to be lost in subpectoral placement, with both implant types enjoying low contracture rates. Asplund et al. concluded similarly in a prospective study using subpectoral textured and smooth Dow Corning Silastic MSI implants. 9 This has allowed surgeons in the United States to use inflatable saline-filled smooth subpectoral implants since the FDA moratorium on silicone gel-filled implants in However, in Britain we tend to favor subglandular textured implants, the majority of which are silicone gel filled. The exact cause of capsular contracture remains a mystery, as does the effect of surface texturing and implant position. Capsule formation is a normal response to the introduction of a foreign material and, like most physiologic responses, is probably a spectrum in terms of both degree and timing. There are general patient factors and local breast factors. Early severe contracture represents one end of the spectrum, rather like the development of hypertrophic scars. The capsule response could be altered by other factors of which infection (clinical and subclinical) is the most plausible Silicone gel bleed also has some support in the literature. 17,18 Our results suggest that smoking may also play a role. The introduction of surface texturing alters the capsule response. Manufacturers use different texture patterns ( fingers, caves, and waves ), the textured elastomer being added as a separate and final process during implant production. The magnitude of the texturing is important. 19 Texturing may produce a more disorganized collagen pattern in the capsule A reduced proportion of type 3 collagen compared with the smooth implant was reported in the rabbit model. 22 Increased type 3 collagen is a feature of Dupuytren s disease. The role of synovial metaplasia is uncertain, although texturing may induce a more persistent and villous hypertrophy, compared with smooth implants. Synovial cells secrete lubricating factors, notably proteoglycans that have been shown to inhibit collagen lattice contracture. 27 Proteoglycan-filled implants have been shown to produce thinner capsules. 28 A recent study examining capsules of different ages histologically found that textured implants were associated with significantly more foreign material and foreign body granulomatous reaction, regardless of age, than smooth implants. 20 Perhaps this represents loss of texturing with time, which may be a problem of all or just some textured implant types. However, regardless of histologic studies, our results suggest that texturing maintains the low capsular contracture rate at 10 years. It has been suggested that subpectoral implants have a low rate of capsular contracture, regardless of surface texturing, because of the massaging action of the overlying pectoralis major. There is no literature histologically comparing the capsules of subpectoral and subglandular implants. Prevention is better than cure as far as capsular contracture is concerned. Apart from surface texturing and the preference for subpectoral or subglandular position, other adjuncts are employed to try to reduce its incidence. In our unit, these include the use of perioperative

5 790 PLASTIC AND RECONSTRUCTIVE SURGERY, September 2000 antibiotics, implant and pocket lavage with Betadine, and the use of nipple shields 29 (a simple transparent adhesive dressing on the nipple-areola complex). Vitamin E and papaverine postoperatively have also been suggested. 1 3,14,30 We have shown that surface texturing successfully reduces and maintains a low incidence of capsular contracture over 10 years for subglandular implants. If previously the main indication for implant removal was capsular contracture, what are the implications for the growing number of asymptomatic aging textured third-generation implants whose longterm integrity is not known? Nicholas Collis, B.Sc., F.R.C.S.(Ed.) 4 Reedling Drive Morley, Leeds West Yorkshire, England United Kingdom LS27 8GQ nicollis@aol.com ACKNOWLEDGMENTS The authors thank Miss Elizabeth Drury for her secretarial support in both the reclamation of patient notes and organizing the review clinic and the Burns and Plastics Research fund for providing the patient gratuities. REFERENCES 1. Rohrich, R. J., Kenkel, J. M., and Adams, W. P. Preventing capsular contracture in breast augmentation: In search of the Holy Grail. Plast. Reconstr. Surg. 103: 1759, Biggs, T. M. Augmentation mammaplasty: A comparative analysis. Plast. Reconstr. Surg. 103: 1761, Discussion, 103: 1763, Becker, H., and Springer, R. Prevention of capsular contracture. Plast. Reconstr. Surg. 103: 1766, Discussions, 103: 1769 and 1773, Hakelius, L., and Ohlsén, L. A clinical comparison of the tendency to capsular contracture between smooth and textured gel-filled silicone mammary implants. Plast. Reconstr. 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