eMedicine Specialties > Radiology > Breast

Breast, Implant Rupture

Author: Richard L Hallett, MD, Adjunct Clinical Assistant Professor, Department of Radiology, Stanford University Medical Center
Contributor Information and Disclosures

Updated: Mar 20, 2008

Introduction

Background

In the early 20th century, many cosmetic breast prosthetic techniques and materials were used for implants; these included polyvinyl alcohol prostheses, paraffin injections, and injections of free silicone. All of these techniques and materials had notable drawbacks and for the most part were abandoned.

Silicone gel breast implants (SGBIs) have been marketed in the United States since 1962. The US Food and Drug Administration (FDA) began regulating SGBIs in 1976 with the passage of the Medical Device Amendments. In 1992, after months of public and private meetings, the FDA restricted the use of SGBIs to specific instances of medical necessity, such as those involving patients who had undergone mastectomy. Saline breast implants have replaced SGBIs as the common breast prosthesis. Details of the FDA rulings and current status updates are available at the Breast Implants information section of the FDA Web site.^1,2,3,4

The ability to reliably evaluate SGBIs with imaging is important because the findings at clinical examination often are nonspecific. The incidence of implant rupture increases with time, and the long-term systemic effects of SGBIs, if any, remain unclear. The diagnosis of SGBI rupture is useful to clinicians and patients; it aids in surgical decision making and helps the patient gain peace of mind.

This article does not address imaging of the rupture of single-lumen saline implants (which usually is clinically obvious because extravasated saline is rapidly absorbed and breast volume quickly decreases at examination).

See also the following related eMedicine topics:
Breast Implants, Silicone: Safety and Efficacy
Breast Reconstruction, Expander-Implant
Uses of the Postoperatively Adjustable Implant in Aesthetic Breast Surgery

Pathophysiology

SGBIs have 2 common designs: single lumen and double lumen. Single-lumen implants contain free silicone gel in a textured or nontextured silicone membrane. Double-lumen implants usually have a saline outer shell that surrounds a silicone inner shell.

Implants may be placed in 2 locations:

• The subglandular location is anterior to the pectoralis muscle, and implantation here is technically easier.
• The subpectoral location is posterior to the pectoralis muscle, and implantation here is technically more difficult.

In essentially all patients, a fibrous capsule forms around the implant (ie, encapsulation). The capsule may be soft and nonpalpable or hard and resistant.

Two types of SGBI rupture can occur:

• Intracapsular rupture occurs when silicone escapes the silastic membrane shell but is contained in the fibrous capsule. This form of SGBI rupture is most common.
• Extracapsular rupture involves the escape of free silicone gel through the fibrous capsule, with extravasation into the breast tissue. Migration of silicone to the axillary lymph nodes also may be present.

Frequency

United States

An estimated 1-2 million patients, or approximately 1% of the adult female population, have breast implants. The incidence of implant rupture increases over time.

• One recent study revealed that the median lifespan of an SGBI is 16.4 years. In that study, 79.1% of implants were intact at 10 years; the percentage decreased to 48.7% at 15 years.⁵

• Another study revealed that of 344 women from Birmingham, Alabama, who were not referred for examination, at least 77% had at least one implant that either was found to have ruptured or that produced an indeterminate finding, when examined via magnetic resonance imaging (MRI). The reported median implant age at rupture was 10.8 years, and submuscular implants were more likely than subglandular ones to rupture.⁶

Mortality/Morbidity

The FDA reviewed 94,120 mandatory reports of SGBI-related adverse events that occurred between 1984 and 1995.⁷ The following terms were used to categorize most adverse events: reaction, failure by rupture, nonspecific adverse reaction, and capsular contracture. Less than 1% of reports involved patient death; of these deaths, none was causally related to an SGBI.

• In 1988, SGBIs accounted for 2.4% of all mandatory device adverse event reports submitted to the FDA. The most common adverse event reported in 1988 was bursting, or rupture. In 1992, when the FDA restricted the use of SGBIs and after public awareness had grown concerning a lack, at that time, of implant-related safety information, SGBI’s accounted for 30.3% of all device reports.³ The most common adverse event reported in 1992 was “reaction.”

Much has been reported on the systemic conditions associated with SGBIs. However, few reports in the peer-reviewed literature support many of the associations. Two well-designed studies were unable to find an association between SGBIs and an increased risk of breast cancer or systemic disease.^8,9 (Investigations in animals have revealed that systemic exposure to silicone may be anticarcinogenic.) While no proven association between SGBIs and connective tissue disease exists, the literature is insufficient to entirely rule out an SGBI link to connective tissue disease – like syndromes. 

Local morbidity does occur and can manifest as pain, paresthesia, capsular contracture, migration, siliconoma, and hardness of or an unnatural feel to the breast. Systemic immunologic reaction to silicone exposure also occurs, but the outcome of this exposure, if any, is unclear.

Presentation

The FDA and various groups, such as the American Society of Plastic and Reconstructive Surgeons, have advised removal of ruptured SGBIs. Because the findings at clinical examination for SGBI rupture often are unreliable, imaging examination with a reliable technique is necessary for preoperative diagnosis.

Preferred Examination

The imaging examinations for SGBI rupture are the following:

• MRI^5,10
• Ultrasonography^5,10
• Computed tomography (CT) scanning 
• Mammography^5,10

Patients should undergo mammography per the American Cancer Society recommendations for breast cancer screening. When implant rupture and extravasation is detected at mammography, further imaging studies may not be required. However, screening mammography alone is insensitive and its findings often are nonspecific in the detection of SGBI rupture.

Limitations of Techniques

MRI is the most accurate imaging examination for the evaluation of SGBI rupture.¹¹ MRI's drawbacks include its cost and possible unavailability. Ultrasonography is fairly accurate and more available than MRI but is highly operator dependent and has a steep learning curve. CT scanning can show findings similar to those obtained with MRI, but the modality involves ionizing radiation, and it has not been systematically studied to the extent that MRI has been. Mammography is inexpensive. Its findings can be specific if free silicone is present, but it has very low sensitivity.¹²

Differential Diagnoses

Other Problems to Be Considered

The differential diagnosis of breast implant rupture includes intracapsular and extracapsular ruptures. Extensive silicone gel bleed may have an identical appearance to early or focal intracapsular rupture at MRI.  Extracapsular rupture involves free silicone in the breast parenchyma; this can simulate other breast masses, including breast cancer, at mammography and ultrasonography. Diligent comparison with prior images and attention to the imaging characteristics should prevent confusion.

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