Historical Summary:

Foam covered devices were made continually from about 1960-1992. In the mid-nineties, they were still manufactured and promoted abroad (Brazil, France, Germany). The products are now regarded as curiosities and many former supporters disclaim ever having used such devices in significant number. Based largely on fraudulent claims, the early versions embodied obvious major risks. The substances and the intermediates used in their fabrication varied widely over the years and the details of the technology used to make the items was unknown until recently.

The clinical basis for the promotion of the devices was non-existent. All items of this type shared the same basic problems but some versions were more hazardous than others. Versions of the sixties with ‘solid’ foam cores were nearly impossible to disinfect and sterilize. Those made in the seventies were plagued with early ruptures and improperly formulated gels. Some later devices were manufactured without shells and amounted to no more than a mass of gel contained within a dipped envelope of RTV on which foam of about 1-2 mm had been bonded. Versions of the eighties had distinct envelopes and resembled conventional prostheses except that they were coated with foam of industrial origin.

The last foam devices to be widely promoted in North America comprised the Meme, Replicon and Optimam. All were similarly constructed. They were regular prostheses to which foam was attached. Surgical misadventures, gross tissue reaction, leaky or ruptured implants, granulomata, inflammatory reactions, skin rashes, lymphatic occlusion and lymph adenopathy are commonly reported by users of the device. The durability of the items is not predictable and gel formulae varies over the years. Some of these gels are very invasive and injurious.

The devices were sold in large numbers in the eighties and were associated with numerous adverse reactions, including infection, neurological disturbances, autoimmune diseases, toxic phenomena, rashes and other manifestations consistent with chronic contact with reactive substances. The devices presented intractable clinical management problems if infected. The formulation of the gels used in this class of product differed substantially from other products. It was supposed to have a strong "shape memory". In 1991 the Optimam was formally withdrawn from the marketplace by the Corporation. The other devices followed a year later when the FDA refused to accept the Corporation's Pre-Market Approval documents.

The Manufacturers:

Foam devices were originally manufactured by Polyplastic of Los Angeles and by the Schulte Medical Corporation. They were later made by the Heyer Schulte Corporation who in turn gave the intellectual property to Markham Medical circa 1975. Concurrently, Markham Medical and associated corporations sold the products directly to users and various companies including 3 T, CBI, Edward Weck Corporation, Real Lapperriere, Unimed and others distributed the product and disseminated inappropriate technical information on it. Edward Weck was the only formally mandated corporation to register the product with the Food and Drug Administration and thus bears the responsibility for the product line. Edward Weck was subsequently acquired by Standards International in the mid-seventies and the Squibb Pharmaceutical Corporation later acquired the conglomerate.

In the late-seventies, key technical staff responsible for production of foam implants left Heyer Schulte. Separate corporations such as Cox Uphoff were founded by departing staff members and contracts for production of the foam implants were continued at Cox Uphoff. The foam implant manufacturing and distribution was consolidated into Aesthetech and Natural-Y when Thomas Salisbury and some of his associates left Cox Uphoff. At that time, the Aesthetech division produced both custom versions as well as commercially serialized foam implants of different types, including variants of the earlier "Ashley", the Vogue and the Meme.

Cox Uphoff did not sell commercial foam prostheses under its own labels; the items were part of contract batches. Custom foam prostheses were made in small numbers. They were based on common gel and multi-lumen CUI shell styles to which the standard foam coating process was used. Some were evidently sold with CUI labeling. Records of the time suggest that these devices were made with the knowledge of the Natural-Y Surgical Specialties group as an extension of the sub-contract relationship. Devices of this kind were evidently inventoried for a long time and a few reappeared in commerce as late as the mid-eighties.

In the mid-eighties, Aesthetech, Natural-Y and other fragmentary "Markham"-related companies were acquired by the Cooper group. They collectively became the plastic surgery division of CooperVision International. In December 1988, the Cooper foam implant business was acquired by the Medical Engineering Corporation which was then a subsidiary of Bristol Meyers. In 1991. Bristol Meyers merged with Squibb Pharmaceutical and became Bristol Meyers Squibb (BMS). This firm bears the responsibility for post-market activity regarding most of the foam implant products.

The Problems:

Foam-coated prostheses are essentially conventional gel-filled, elastomer-shelled implants and share all problems of conventional silicone gel implants. They have supplemental foam coatings bonded to the shell surface with room temperature vulcanizing adhesives which create additional risks. All are subject to oil effusion, gel leakage, shell rupture and other problems which are widely encountered in gel-filled implants. Unique aspects of their construction and fabrication complicate the study of their behavior.

Other problems outflow from the poor quality of the products, the methods of use, the haphazard processing of raw materials and the incorrectly designed assembly techniques. Losses of oil and gel via effusion across imperfectly manufactured shells take place to a greater extent than in conventionally made gel prostheses, these effluents have a special role in foam prostheses. The effluents may soak into the foam which acts as a storage system causing the impurities to be released as a bolus soon after implantation.

Technical Aspects:

Fabrication of foam coated prostheses depends on multistage operations and involve heat and reactive substances sometimes used concurrently. Foam materials employed for coating have historically been poorly controlled substances designed for general industrial and household applications. They contain large quantities of impurities inherent to foam fabrication techniques.

The level of impurities in such prostheses is much larger than the average expected in medical products. The oil/gel content at the moment of use also depends on storage time and is markedly influenced by attempted recleaning, washing, immersion in disinfectants and presurgical re-sterilization. These processes may also affect the performance of the product and the rate at which impurities are released from the system.

For example, the thermal history and the foam adhesive contributes significantly to the susceptibility of the foam to degrade. Thermal treatments cause the foam to react and the reaction is sufficiently so severe that it imparts coloration to the substance. Similarly the adhesive is an acid producing substance during its vulcanization (setting) stage. Subsequent thermal curing processes which may be used to complete the setting and the final sterilization may further damage and alter the foam coating and make it increasingly susceptible to later chemical attack under the aggressive aqueous environment of a living organisms.

The adhesive used to bond the foam (RTV) and also used incidentally to reinforce the weak shell depends on ambient moisture for initial vulcanization. Its performance is moisture and impurity sensitive. In contact with a foam of variable composition containing impurities of various kinds, its performance is erratic and finished products made up of comparatively hard material to very soft frangible adhesive surfaces may result. This affects the abrasion susceptibility of the product and may cause some production batches to release large quantities of RTV as well as foam debris.

The collectivity of such factors ensure that foam-coated devices contain altered, degradable polyurethane-derived material, residuals of fabrication, effusing oils and gel in addition to production impurities transferred from repeated handling. The design of the devices further ensures that they have a large surface area (foam pores) which facilitate penetration by fluids. Thus, the devices are predisposed to erratic degradation and solubilization because of prior steps in the production sequence which damage the chemical structure of the coating.

In vivo degradative reactions are initially rapid and culminate in uplifting of the foam coating and its early incorporation into capsular tissue, usually with large quantities of deposited fibrin from adhering blood products. Once detached, the coating increases significantly in surface area and separation into fragments of several mm takes place within the following month. The product becomes very weak and is further comminuted by growing capsular tissue and by changing stresses in the pericapsular area. The rate of chemical dissolution of the first fractions of reactive material is rapid and further increases in the first month. This stage is generally complete within about a year, leaving more resistent solid material behind.

The following period is followed by a slower process whereby solid substances are attacked via biological processes driven in part by the presence of catabolic entities which attempt to dissolve the material through normal phagocytotic activity. During this stage, aromatic segments are produced and converted to reactive chromophoric material which may bind into tissue imparting to it an orange or amber color.

Aromatic acetylated derivatives of amines are produced during this stage and, for some users, the products appear in blood and in urine. The normal metabolites are acetylated derivatives although analytical techniques usually express the quantities as "TDA" levels. Later stages of the process attack the more resistant residuals and the solubilization process may last for 5-8 years. Most users still show small unresorbed residuals after as much as 15-20 years.

Degradation of material comprised in foam coated implants in vivo drastically alters the composition and the quantities of substances with potential impact on users. Adverse information on the health effects of foam implants is not widely understood within the medical community. The information is blurred by media activity and publications of articles on conventional silicone gel implants. It is further diluted by the dissemination of incorrect information on saline-containing implants with problems of their own.

Publications on breast prostheses and their problems do not frequently differentiate the grossly different mechanisms involved in deterioration of these various systems and the way by which they injure. Most of these publications and the media activity they elicited correlate with the late-eighties and continue to this day.

The Role of Professionals:

Plastic surgery, being a practical discipline, contributed relatively little to the information base on the performance and the risks of these devices. Publications in that sector focused mainly on short term aesthetic results and did not address basic issues such as suitability of design, control of effluents, deterioration and focal adverse reaction of a chronic nature.

Articles and symposia presentations between 1985 and 1990 openly discussed the foam issue but did not recognize that the material was a misplaced industrial product of non-uniform composition and of unpredictable properties. They also failed to address the variability of sterilization processes in the context of products with elevated bioburden, porous surfaces and items produced individually, by hand, under poorly controlled environments.

Other diversions occurred during the mid and late-eighties when promotional activity on the part of foam prostheses manufacturers and distributor was particularly intense. The information conveyed from these sources was transparently faulty and, in some cases absurd. The claims, in particular with reference to control of post-surgical contracture, were not supportable. Discussions and guidelines on removal of such prostheses following misadventures were also faulty and did not take into consideration the dynamics of degradation.

In retrospect, it appears that most users of the foam devices encountered problems. Some of the adverse information appeared in publications but was largely disregarded by the surgical community or overshadowed by promotion. .Additional articles may have written but were not published. It was a time when manufacturers, proponents and distributors were quarreling with editors, governments and clinicians regarding the release of information on adverse reactions and complications.

Litigation by injured users took place at an increasing rate towards the end of that period and anecdotes of severe adverse reactions became known to the public. Explantations took place in greater numbers and early publications focussed on infective problems. The plastic surgery community became more sensitive to possible infective sequelae and many surgeons attempted to ‘re-sterilize’ the products themselves or immersed the items extemporaneously in "cold sterilant solutions" prior to implantation. The issue of unpredictable sterility for foam implants was discussed openly in meetings of the plastic surgery community. These extemporaneous processes introduced still more variability in the performance of the foam-based materials and their ability to release reactive soluble substances in vivo.

Future Trends and Problems:

During this debate, issues surrounding the foam-coated implants were largely forgotten as the devices fell into disrepute. Problems posed by users who still have implants in situ have not been addressed. There is no consensus on guidelines which are applicable to this sub-population will ultimately reappear in the health care system with ruptured prostheses and other late adverse reactions. The community who had originally supported the foam implants with claims of safety and good cosmetic results has now become silent. Explanting surgeons rarely publish the adverse findings on difficult explantations and the alarming presentation of contaminated tissues that surrounds extravasated degraded foam implants after many years in situ. To this day, there is little published information on the long term fate of users, the impact of these products on surrounding tissue, the dynamics of deterioration, the metabolization and dissemination of the debris and the methodologies for safe removal of the residues.