Types of breast implants: surface and fill

How are breast implants classified?

A breast implant consists of an outer shell and the fill inside it. A 2017 meta-analysis explained that implant models differ in size, fill, shape, and shell characteristics, and that the shell surface can be smooth or textured ^[1]. Breast augmentation is one of the most commonly performed surgeries in the United States, and silicone implants in particular have advanced considerably over the years ^[4].

When choosing an implant, it is easier to understand the options by thinking about the fill and the surface separately. However, the research summaries reviewed here did not compare satisfaction or complication rates across types of implants at a glance, so this article focuses on what has been established about each characteristic.

Fill: silicone gel and saline

In the United States, silicone gel implants were subject to a moratorium (a suspension of use) in 1992 and were approved again in 2006, and in the meantime there were many changes in how they are manufactured and used ^[5]. In contrast, saline implants have kept several clear advantages without major changes, but they were assessed as not having undergone the same technological advances as silicone gel implants ^[5]. The research summaries reviewed here did not specify what the advantages of saline implants are.

Silicone is widely used as a medical material because it causes little reaction in the body and has low toxicity ^[6]. However, capsular contracture remains a concern with long-term implants, so research on improving the surface continues, such as suppressing scar tissue formation (fibrosis) with anti-inflammatory drugs or antibiotics, adjusting the microstructure of the surface, and plasma treatment ^[6]. This research has been summarized as still being at a stage with limitations ^[6].

Surface: smooth and textured

A 2017 review summarized changes in implant surfaces over the past 20 years, presented long-term safety data from a 10-year follow-up clinical study conducted in the United States (Core study), and compared the main benefits and risks of smooth and textured implants ^[7]. The same review also discussed perspectives on breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) ^[7]. Because these are data from the United States, it cannot be assumed that the same results would be seen in Korean patients.

Looking at capsular contracture alone, a 2017 meta-analysis that reanalyzed 15 studies, including 13 randomized clinical trials, concluded that textured implants appear to lower the risk of capsular contracture ^[1]. However, the same study stated that textured implants may be associated with an increased risk of anaplastic large cell lymphoma ^[1]. In other words, a choice that reduces one complication is tied to another risk.

The research summaries reviewed here did not give figures for how often lymphoma occurs with each type of surface. The symptoms and diagnosis of implant-associated lymphoma are explained in detail in a separate article in this Surgery Guide. When choosing a surface, it is a good idea to get an explanation of both the risk of capsular contracture and the risk of lymphoma, and if you already have implants, to find out what type of surface they have.

Rupture of silicone implants

A 2017 review of rupture pooled the results of manufacturer clinical studies that followed recent generations of silicone implants, and summarized that the rupture rate is very low at first but begins to rise 6 to 8 years after implantation ^[2]. The most common cause of rupture was damage caused by surgical instruments when the implant was inserted during surgery ^[2].

Most silicone implant ruptures are not detected by physical examination alone ^[2]. Rupture can be confirmed by physical examination, ultrasound, or magnetic resonance imaging (MRI), and if there are symptoms, they can show up as capsular contracture, a breast lump, or a change in breast shape ^[2]. Leaked silicone may stay within the capsule surrounding the implant or spread into the breast tissue ^[2].

The same review summarized that the consensus in the literature is that there are no health risks associated with rupture itself ^[2]. For a rupture with symptoms, it presented a choice between monitoring the condition and removing the implant and the capsule, with or without replacing it with a new implant ^[2].

Common and rare complications

A 2020 review named rupture and capsular contracture as common complications that have been widely studied ^[3]. As the number of people with implants has grown, so has the likelihood of encountering rare complications such as late seroma (fluid collection), late infection, enlarged internal mammary lymph nodes, capsular granulomas, implant-associated desmoid tumors, and BIA-ALCL ^[3]. It was stressed that diagnosing and managing late seroma and BIA-ALCL in particular are important ^[3].

A 2022 review of silicone implants listed pain, swelling, redness, infection, capsular contracture, rupture, and gel bleed (gel-bleed) as local adverse reactions ^[8]. The authors of this review concluded that there is a causal relationship between silicone implants and systemic symptoms such as chronic fatigue and joint pain, but this conclusion takes the form of expert opinion based on applying criteria for judging causality ^[8]. Breast implant illness is covered in more detail in a separate article.

What to check during your consultation

Which implant is right for you depends on your body type, the condition of your tissue, the shape you want, and how you feel about accepting each risk. Results differ from person to person even with the same implant, so it is a good idea to check the following during your examination.

• The fill and surface type of the implant that will be used
• The risk of capsular contracture and lymphoma depending on the surface type
• How and when to check for rupture
• What steps to take if, after a long time, one breast swells or changes shape
• Situations in which replacement or removal may become necessary