It is normal for some scar tissue to form around the implant following breast augmentation surgery. In some cases this scar tissue is excessive and tightens around the implant. The scar forms a capsule or covering around the implant and is given the term capsular contracture when it tightens all around the implant. This is graded using a Baker classification with grades 1 to 4 in increasing severity. In grade I, the breast feels soft and natural. In grade II the implant may be palapable. Generally speaking, grades I and II are cosmetically acceptable. In grade III, the breast is more firm. The implant is palpable and may be visible. There may be some distortion to the shape of the breast. In grade IV the breast becomes hard and sometimes cold or tender. Grade III and IV are not cosmetically acceptable and generally require treatment. Capsular contracture may happen to one or both sides post enlargement.
Capsule formation is evident 4 to 6 weeks post breast augmentation. When examined under a microscope, the mature or well formed capsule is made up of cells similar to those found in scar tissue. The average thickness of a capsule is 1.3mm but may be up to 4mm. Most believe that 90% of capsules are stable by the first year but in some cases, a capsule may continue to form there after becoming a progressive problem over time.
The cause for capsular contracture is very unclear but a number of factors are thought to play a role. Low grade or sub-acute infection is thought by many to promote capsular contracture. One study identified bacterial contamination in over half of the capsules around implants and found this figure to be much higher if the capsular contracture was painful. Numerous steps are taken before and during the operation to reduce the risks of bacterial contamination. Haematoma (bleeding) or seroma (fluid) around the implant may also be contributing factors.
A breast implant has a textured or smooth surface. It is generally agreed that a textured implant surface decreases the prevalence of grade III and grade IV capsular contracture. The occurence of capsular contracture is higher for implants with a smooth surface. In one study at the 10-year point, 65% of patients with smooth implants had significant contractures, compared with 11% of patients with textured implants.
It was previously said that saline filled implants may produce less capsular contracture than silicone gel implants. This is likely explained by the fact that older implants had the tendency for silicone to leak slowly over time causing a low grade chronic inflammatory reaction which may well have been a factor in capsular contracture formation. Newer implant filler materials are “cohesive silicone gel” which means there is no possibility of a silicone bleed (leak) even in the event of an implant rupturing. In particular there is no evidence that silicone itself promotes capsular contracture formation and hence there is no advantage on this basis to a saline implant.
Some surgeons have suggested that placing the implant beneath the muscle (sub-muscular) may produce less capsular contracture than above the muscle (sub-glandular). One theory is that the muscle essentially massages the implant.
Generally speaking, placing the implant above the muscle is often preferential for many reasons so the advantages and disadvantages of implant location are weighed up on a case by case basis.
The treatment for grade III and grade IV capsular contracture is surgical. The most effective option is to exchange the implants and remove the capsule completely. In some cases it is difficult to remove the capsule in its entirety e.g. the capsule is sub-muscular and strongly adherent to ribs or the capsule may be thin and flimsy in parts.
A recent study found that the capsular contracture recurred in about 10% of patients after removal. Recurrent capsular contracture is a difficult problem for both patient and surgeon. Surgery is an option and may involve removing the capsule, changing the type of implant or the pocket location. In a small number of cases, treatment may involve removing the implants and reshaping the breast without them.
The individual biologic response to an implant may play a large role which means that capsular contracture is likely to develop despite every best effort to avoid it. Advances in implant components, surface texture and filler materials continue to evolve. This coupled with technology and an increased understanding of the science of scar formation means that research continues to yield valuable information about capsular contracture.