Breast augmentation is a surgical procedure where a saline or silicone implant is placed retroglandular or retropectoral within the breast. It can be performed for cosmetic augmentation, congenital malformations, or reconstruction after mastectomy. Approximately 3.5 million people in the United States have breast implants. A possible complication after surgical implantation of saline or silicone breast implants is implant rupture. There are many different varieties of saline and silicone implants, but what is most important in the evaluation of rupture is just to know if it is a saline or silicone implant. Saline rupture results in the extravasation of a simple saline solution that is harmless and reabsorbed by the body. Silicone implant rupture can lead to either intracapsular or extracapsular involvement. The body creates a fibrous capsule scar as a normal reaction to the foreign implant; an implant rupture contained within the fibrous capsule is referred to as an intracapsular rupture. Extravasation of silicone outside of the fibrous capsule is called an extracapsular rupture. An extracapsular rupture results in silicone gel extravasating into the surrounding tissues. One important note is that there cannot be an extracapsular rupture without an intracapsular rupture.
There is a distinction between old silicone prosthesis and cohesive, new silicone generations. Apart from some exceptional circumstances, cohesive silicone will not spread to surrounding tissue; however, old silicone was subject to a wide dissemination, and in rare cases, migrated as far as the inguinal area.
Some of the most common causes of implant rupture are secondary to the normal aging of the implant as all prostheses walls will rupture eventually. Literature and personal experience allow physicians to estimate this timeframe from 25 to 35 years. All ruptures occurring within 20 years are premature. These early ruptures have different causes which include incompetent valves, manufacturing defects, and underfilling that leads to folds thus provoking a premature weakness in the wall. Most trauma does not cause a prosthesis rupture except, possibly, in the case of blunt trauma. Nonpenetrating traumas were encountered in closed capsulotomies of old silicone prostheses, but are these are seen less today.
The incidence of implant rupture increases with the age of the implant. Prosthesis wall thickness does not play any determinant role in ruptures, as companies offer inflatable prostheses of varying wall thicknesses, and these have a similar rupture rate. Overfilling is rarely responsible for ruptures.
In saline prostheses, apart from the diminution in breast volume, few other symptoms can be identified. If exploration happens at a very early stage after deflation, the surgeon will notice a certain amount of water still in the capsular pocket. If surgery is performed long after deflation, water in the capsular pocket will have diminished.
In case of old silicone prostheses ruptures, silicone will be free inside the capsular pocket, and apart from the inflammatory process in the thickened capsule, some free and encapsulated silicone (granuloma) can be found in the surrounding tissue.
For saline prostheses, the most common sign associated with implant rupture is the evidence of volume diminution. There is no pain except in rare circumstances. In silicone prosthesis, there could be some degree of chest-wall pain. A saline implant rupture is easy to detect on physical examination. It is often referred to as a deflated breast. It decreases in size over the course of a few days. If the saline implant deflates within a few days of insertion is it suggestive of iatrogenic damage or an improperly closed valve. For an older implant, a recent history of trauma could be the cause of the rupture. Silicone implant rupture is difficult to detect on physical examination, with a majority of cases being intracapsular, further evaluation with imaging is often required. Extracapsular silicone implant ruptures can sometimes produce a palpable mass as inflammation and granulomatous tissue forms.
A saline implant rupture often requires no radiographic evaluation. As described above, a simple clinical evaluation demonstrating volume loss is sufficient. If mammography imaging is obtained, then the implant will often demonstrate a wrinkled appearance. An intact implant will demonstrate a simple anechoic interior on ultrasound, while a rupture will demonstrate folds or wrinkles in the implant capsule. MRI will show a saline implant follow fluid signal on all sequences.
An intracapsular silicone implant rupture is very difficult to see on mammography. A bulging of the implant contour can suggest an intracapsular rupture. Ultrasound also lacks sensitivity to show intracapsular ruptures. The most reliable finding is called a stepladder sign, in which multiple, linear echoes are noted in the implant. MRI is the most sensitive at detecting silicone implant rupture. The demonstration of silicone on both sides of a radial fold is known as the keyhole, noose, or teardrop sign (all referring to the same finding). The finding of multiple folds of the implant shell layering upon itself is referred to as the linguine sign and highly indicative of an intracapsular rupture. This should not be confused with the normal radial folds/creases of an implant, which are often straight, thick, short, and extend to the periphery of the shell. CT imaging will also demonstrate the characteristic linguine sign, but with an overall low sensitivity and high radiation dose is not used to evaluate implant rupture. It is often incidentally seen on CT.
Extracapsular rupture can often be seen with mammography and ultrasound, showing the extravasated silicone in the surrounding tissues or even axillary lymph nodes. The snowstorm sign is a sonographic finding of silicone gel droplets mixed with breast tissue showing a heterogeneous echogenic appearance resulting from dispersion of the ultrasound beam. MRI is still the modality of choice to determine the extent of the extravasation. The silicone will have low signal on T1, and a high signal on T2 fat-suppressed images. Computed tomography is not used to evaluate extracapsular rupture because the silicone and the surrounding soft tissues with demonstrate a similar radiodensity.
The empty shell of a ruptured saline implant should be removed. A ruptured silicone implant intracapsular or extracapsular should be removed because of the possible interaction with surrounding tissue and possible spread to local lymph nodes. A patient may not wish for the implant to be removed and in such a case, close surveillance is suggested. If an intracapsular rupture occurs, then a capsulectomy can be performed. If all silicone has been cleaned (this happens in very recent ruptures), the surgeon may not remove the fibrous capsule. If there is a doubt about silicone persistence, the surgeon will attempt to remove the entire fibrous capsule that has been invaded and infiltrated by silicone. A capsulectomy will be necessary in case of calcification. If the rupture is extracapsular, then it is possible that the patient will need several surgeries to retrieve all of the extravasated silicone gel.
Like everything else in life, breast implants have an expiration date and need to be replaced to avoid complications like implant rupture. As discussed above, the rate of implant rupture is directly related to the age of the implant. With over 3.5 million breast implants in the United States, it is imperative for medical professionals to understand the common presentation, diagnostic exams to order, common imaging findings, and management.