BREAST AUGMENTATION: CAPSULAR CONTRACTURES
BREAST AUGMENTATION: IMPLANT EVOLUTION
Breast augmentation is the most popular aesthetic surgery procedure performed. This has led to an extensive history on its safety and complications in comparison to other procedures. Throughout history many different materials have been used for implants such as shellac, beeswax, epoxy resin, petroleum jelly, Teflon and many more. The introduction of silicone gel implants in 1962 was a major discovery for breast augmentation surgery. The varying kinds of implants can be separated into 5 categories based on shell thickness, texture and implant fill. Currently the implants available on market are divided by gel fill, either saline or silicone. The silicone implants are then further subdivided by form as either stable or soft, by shell as textured or smooth and finally by shape as round or anatomical.
The first silicone implants were made of a viscous silicone gel in a thick tear-drop shaped shell. These early implants had a high early capsular contraction rate which lead to the next generation of implants being much softer, and seamless. These smoother implants reduced the capsular contraction rates but had a problem called gel bleed, which caused a pathogenesis of capsular contracture. From these two iterations, a third generation of implants were created with a stronger silicone shell to prevent leakage. Later developments include changes on the shell of the implant, ranging from polyurethane foam to texturing of the pores which lead to much lower capsular contracture rates.
WHAT CAUSES CAPSULAR CONTRACTION?
Capsular contracture is one of the most significant drawbacks for breast augmentation, the changes of capsular contractures requiring revisional surgery is between 5 to 59%. It most commonly occurs within the first 18 months after surgery. Although recent studies suggest early capsular contractures can occur up to 3 years following surgery.
The pathogenesis of capsular contractures is not certain and most likely is dependent on multiple factors. There are currently two major theories; scar formation and infective theories. Many studies have been done to implicate any factors involved in surgery, however no definitive study exists that indicates any particular variable causes capsular contractures. In essence it is thought both pathways result in overstimulation of the local immune response resulting in pathological capsular contracture. Some factors that were researched as potential causes are explored below:
The most common incisions for breast augmentation is, infra-mammary followed by trans-axillary and peri-areolar access points. Umbilical incisions and access is a surgical possibility but often has little reasonable justification. There is evidence that the peri-areolar incision which has reduced access also exposes the implant to potentially higher risks of bacterial contamination which then leads to an increased capsular contracture rates. This is at least in part due to the presence of bacteria in the breast and nipple ductal system. A finding from 2012 is that in trans-axillary incisions, there is an increased rate of capsular contraction than both infra-mammary and peri-areolar incisions.
A major deciding factor on capsular contractions is the type of implant, saline implants were originally thought to have a major advantage due to the lower rate of capsular contraction. However, since then this evidence has been disproved though a systematic analysis of randomised controlled trials which did not lead to this same conclusion. Similarly textured implants are known to have lower capsular contracture rates but are associated with a rare lymphoma.
The studies done on surgical pockets in which implants are inserted into are divided based on texture, either textured or smooth. Surgical pockets are either subglandular (placed behind ONLY the skin and breast gland) or sub-pectoral (placed behind the skin, breast gland AND pectoral muscle). From a systemic review in 2006, consisting of 6 randomised controlled trials and 235 patients, there was no difference in one trial between capsular contracture rates of textured and smooth implants, whilst the rest confirmed a lower capsular contracture rates for patients with textured implants. A smaller study on 55 sub-pectoral implants noted that less capsular contracture rates were observed in textured implants however only by a small amount (15% to 8.6%).
There is some evidence that peri-prosthetic drains are related to higher risks of infection and hence also capsular contractures. Many surgeons choose not to use drains in primary breast augmentations.
PERI-OPERATIVE ANTIBIOTICS/IRRIGATION OF POCKET WITH ANTISEPTICS/ANTIBIOTICS SOLUTION
There is significant evidence supporting peri-prosthetic and subclinical infection theory (infection with no signs/symptoms), however it is not clear if this is the cause of capsular contractures. It has been demonstrated that contamination by implicated organisms (e.g. staphylococcus aureus) accelerate the rate of capsular contraction. The results from pocket irrigation with antiseptics and antibiotics have been conflicting as a study using a triple antibiotic solution (Adam’s solution) showed a reduction of capsular contracture rates. Contrast to this a study on preoperative antibiotics showed no statistical difference in capsular contraction rates.
WHAT HAPPENS AFTER?
Capsular contractions are one of the most common reasons for patients to undergo reoperation. Once a significant capsular contraction of grade III/IV the only option is surgery. The options include capsulectomy, scoring and implant exchange only, capsulectomy and implant exchange or neo-pocket creation and implant exchange. Due to the bacterial contamination of capsular contractures, it is often advised to excise the capsule and where possible – create a new implant pocket for a new implant.
Recently, Acellular Dermal Matric (ADM) has been used to prevent capsular contractures by providing an abrupt disruption on the forming capsule – hence this eases capsular contractures and is often used in revisional augmentation surgery.