An implant capsule is a natural and expected physiological response of the body to the presence of any foreign material, such as a medical implant. The body’s immune system recognizes the implant as a foreign object and forms a protective layer of fibrous tissue around it. This layer walls off the foreign material from the rest of the body. The formation of this capsule is a normal part of the healing process following implant placement.
How Implant Capsules Form
The formation of an implant capsule begins almost immediately after an implant is placed in the body. This process, known as a foreign body reaction, involves several overlapping phases that mirror wound healing. Initially, blood and plasma proteins coat the implant surface, followed by the accumulation of immune cells like fibroblasts and macrophages. These cells then begin to deposit collagen, which is the main component of the fibrous capsule.
The capsule typically consists of three layers: an inner layer of immune cells, a middle layer containing blood vessels, and an outer layer primarily composed of collagen. Under normal circumstances, this capsule remains thin and soft, helping to keep the implant in place. This process isolates the implant from surrounding tissues.
When a Capsule Becomes Problematic
While capsule formation is normal, sometimes the fibrous tissue can become abnormally thick and tighten around the implant, a condition known as capsular contracture. This tightening can cause the breast to feel firm or hard to the touch, differing noticeably from natural breast tissue or the unaffected breast. The breast may also appear distorted, becoming rounder, higher, or misshapen, and the implant might feel less mobile. Some individuals experience pain or a sensation of tightness in the affected breast.
The severity of capsular contracture is often classified using the Baker grading scale, which ranges from Grade I to Grade IV. Grade I indicates a soft breast with a natural appearance, where the scar tissue does not interfere with the breast’s size, shape, or texture. Grade II means the breast feels slightly firm but still looks normal. In Grade III, the breast becomes firm and exhibits an obvious cosmetic distortion, such as an overly round appearance or misshapen nipples, though pain may not always be present. Grade IV is the most severe, characterized by a very hard, painful, and tender breast with pronounced distortion and potential coldness to the touch.
Causes and Risk Factors
The exact cause of capsular contracture is not fully understood, but several factors are believed to contribute to its development. One prominent theory suggests that chronic inflammation triggers the excessive collagen deposition that leads to a thickened, contracting capsule. Subclinical infection, often involving bacteria like Staphylococcus epidermidis or Cutibacterium acnes, can form a thin layer called biofilm around the implant. This low-grade, persistent infection can stimulate an exaggerated inflammatory response, leading to increased scar tissue formation.
Other contributing factors include hematoma or seroma formation, which are accumulations of blood or fluid around the implant site after surgery. Implant rupture can also incite an inflammatory reaction, as the body reacts to the leaked material. Genetic predisposition plays a role, as some individuals are naturally more prone to developing thick scar tissue. Additionally, the type and texture of the implant, as well as surgical techniques like implant placement (above or below the muscle) and incision site, can influence the risk. Radiation therapy after implant insertion is also associated with a higher risk of capsular contracture.
Prevention and Treatment
Preventing capsular contracture involves several strategies aimed at minimizing inflammation and infection. Meticulous surgical technique, including careful handling of tissues and minimizing bleeding, is important. Surgeons may use surgical drains for a few days post-operation to prevent fluid or blood accumulation, which can host bacteria. The use of antibiotics, both during and after surgery, can help reduce the risk of bacterial contamination and biofilm formation. Some studies suggest that textured implants and submuscular placement may lead to lower rates of contracture compared to smooth implants and placement above the muscle.
For established capsular contracture, treatment options vary depending on the severity. Non-surgical approaches may include therapeutic ultrasound or the use of certain anti-inflammatory medications, such as leukotriene inhibitors like zafirlukast, which are typically used for asthma but can block the immune system’s inflammatory response. However, surgical intervention is often necessary for more advanced cases. Surgical options include capsulectomy, which involves the partial or complete removal of the fibrous capsule, or capsulotomy, where incisions are made in the capsule to release the tightness and create more space for the implant. In some cases, the existing implant may be exchanged for a new one, sometimes with the addition of a biological material like acellular dermal matrix (ADM) to provide extra support and potentially reduce recurrence. Consulting a medical professional is important for proper diagnosis and to determine the most suitable treatment approach.