Less maligned, but cut from the same cloth,

other siliconeimplants also have adverse effects.

(Medical News & Perspectives)

The PR teams hired by the manufacturers and plastic surgeons often use the
(il)logic that breast implants must be okay because other silicone
implants are "safe."


Title:
Authors: Randall, Teri
Citation: JAMA, The Journal of the American Medical Association, July
1, 1992 v268 n1 p12(2)



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Abstract: The controversy over the health aspects of silicone breast
implants has alerted researchers to possible side effects of
other polymers used in medicine. These range from artificial
lenses in the eye to artificial joints, pacemakers and
catheters. Millions of people have received silicone implants,
but the long-term safety of the devices has never been
studied. Doctors knew that the body produces a fibrous capsule
around the implant, and they thought this capsule would
protect the body. But researchers have found silicone
particles in the tissue surrounding the implant, and even in
lymph nodes near the implant. The body produces an immune
response to the silicone particles, which could damage joints.
Many surgeons say the body produces an immune response to any
foreign object placed in the body, but the response is usually
benign. If use of these materials was restricted, orthopedic
surgery would cease to exist.

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THE CURRENT controversy over silicone runs deeper than the problem of
breast implants that rupture or bleed through their silicone shells
(JAMA. 1992;267:2439-2442). At the heart of the controversy is the
body's reaction to the polymer that for three decades has been
championed as inert, noncytotoxic, and biocompatible.

As a class of materials, silicone polymers are considered nontoxic in
both animal and tissue culture studies. Millions of patients worldwide
have received silicone implants, yet many researchers say that the
long-term biocompatibility of silicone has never been thoroughly
established scientifically. Only recently has the Food and Drug
Administration begun to require the manufacturers of silicone breast,
penile, and testicular implants to submit data from rigorous trials
(JAMA. 1992;267:2578-2579).

However these scientific questions are resolved, the result is likely to
influence the fate not only of breast implants, but also the entire
gamut of implants and devices that contain silicone.

Since the mid-1960s, medical device manufacturers have molded this
versatile material into a vast array of medical apparatuses. From eye
lenses to bunions and almost every joint and private part in between, a
silicone-based device has been made to repair what disease or time has
taken away, or to augment what nature has never given.

These devices include silicone-based testicular implants (resembling
breast implants in fabrication) and penile prostheses of the semirigid
rod and inflatable varieties. There also are implants for the fingers,
thumbs, and wrists for patients with rheumatoid arthritis.

In addition, elbows, shoulders, temporomandibular joints (TMJs), and
middle ears now are fitted with silicone implants. And pacemaker wires,
silk sutures, needles, and catheters are coated with silicone.

Some men now are seeking solid silicone implants for their calves and
chests to achieve a more muscular look. The implants' early recipients
were bodybuilders in Beverly Hills, Calif, but the procedure is gaining
popularity throughout the country, plastic and reconstructive surgeons
report.

For patients born with pectus excavatum, or funnel breast, plastic
surgeons place a solid silicone implant shaped like a breast implant
into the chest but with the rounded portion facing inward.

Isolating Self From Nonself

At least on the macroscopic level, the body appears to tolerate these
foreign objects. Mammals and invertebrates alike, when implanted with a
large, inert object, construct a natural barrier made of fibrous scar
tissue around that object.

Once formed, this fibrous capsule separates self from nonself and, from
the surgeon's point of view, provides the additional benefit of helping
to stabilize the implant in the body. This reaction is not unique to
silicone, but is observed with titanium, cement, plastic, polyethylene,
and many other materials.

For almost two decades, however, the response at the microscopic level
has been troubling researchers from disciplines as diverse as hand
surgery, urology, and oral surgery, as well as plastic and
reconstructive surgery.

Microscopic examination of biopsy specimens reveals that silicone
implants shed microparticles of silicone (<100 [mu] m) into the
surrounding tissue. These particles are seen by the body as foreign, and
they elicit an immune reaction that involves the local formation of
foreign-body granulomas by multinucleated giant cells.

X-ray microanalysis and electron microscopy have revealed this immune
response in the tissue surrounding breast implants (Plast Reconstr Surg.
1990;85: 38-41), urinary sphincteric implants and penile prostheses (J
Urol. 1991;146:319-322), TMJ implants (Oral Surg Oral Med Oral Pathol.
1985;59:449-452), and implants of the hand and wrist (J Hand Surg Am.
1986;11:624-638), to name a few.

Of considerable concern to some but not all researchers is the discovery
of silicone granulomas in the lymph nodes near these same implants
(Semin Arthritis Rheum. 1987;17:112-118; J Urol. 1991;146:319-322; Oral
Surg Oral Med Oral Pathol. 1985;59:449-452; and J Hand Surg Am.
1988;13:411-412). Some of these investigators and others have also
reported lymphadenopathy and lymphadenitis after implantation with
silicone prostheses.

Around thumb and wrist silicone implants in humans, the local
inflammatory response is so aggressive, a recent study shows, that it
lyses nearby bone and can result in pathologic fractures (J Hand Surg
Am. 1991;16:835-843).

Recently, urologists at Mayo Clinic, Rochester, Minn, took biopsy
specimens from the fibrous sheath surrounding the penile prostheses or
urinary sphincteric implants of 25 patients who were undergoing repair
or replacement of their implants. They detected silicone particles, and
usually the presence of foreign-body granulomas, in 72% of the patients
(Figure).

The prostheses had been in place for 2 months to 5 years, but a majority
had been in place less than 2 years. The study included most types and
brands of prostheses (J Urol. 1991;146:319-322).

Granulomas in Lymph Nodes

These researchers also took biopsy specimens from clinically enlarged
inguinal nodes in three patients and detected silicone particles and
foreign-body granulomas in all three. They also examined tissue from the
periaortic node in one patient and found silicone particles.

Because biopsy specimens were taken from only four lymph nodes, the
study did not determine the overall rate of migration of silicone
particles to the lymph nodes. The researchers also did not determine the
degree that silicone is disseminated throughout the lymph system,
because they did not examine tissue beyond the draining lymph node.

In their discussion, the authors suggest that "the presence of silicone
in lymph nodes of itself is not important." However, they acknowledge
there is some controversy in the hand surgery literature as to whether
there is increased incidence of malignant lymphoma in patients with
joint replacements and lymphadenopathy. A number of cases of malignant
lymphoma have been reported in these patients who have silicone in their
enlarged lymph nodes (Hand. 1982;14:326; and Diagn Histopathol.
1982;5:133).

David M. Barrett, MD, professor and chair of the Department of Urology
at the Mayo Clinic, and the study's first author, responds that "our
bodies come into contact with all kinds of particles over the years.
These undergo phagocytosis, granulomas are formed, some of the particles
are broken down in the cells, and some of them are not. But this doesn't
necessarily imply that this is a deleterious reaction in the patient."

The study concludes that there is no evidence that particle shedding and
subsequent migration have either short-term or intermediate-term
deleterious effects on the host. Long-term assessment (20 years or more)
is needed to ultimately determine the inherent risks, the authors
conclude.

In 1985, a group of oral surgeons observed a similar immune response in
the parotid lymph node and tissue surrounding the TMJs of eight patients
who received silicone disk implants (Oral Surg Oral Med Oral Pathol.
1985;59:449-452).

The authors, Franklin Dolwick, DMD, PhD, from the University of Florida
College of Dentistry, Gainesville, and Thomas Aufdemorte, DDS, from the
University of Texas Health Science Center, San Antonio, express
considerably more concern over the formation of foreign-body granulomas
than the Mayo group.

The authors state, "it is most probable that associated pathologic
changes with resultant dysfunction and morbidity may coexist" with the
foreign-body type of granulomatous inflammation. They also cite reports
from the hand surgery literature of lymphadenopathy and inflammation
mimicking rheumatoid synovitis in sites adjacent to silicone implant
material.

"Thus," they write, "the contention by some that the foreign-body giant
cell response to this implant material is insignificant is not a tenable
thesis in our view. Consequently, any material associated with such a
response should receive full evaluation and study, particularly with
reference to the risk-benefits ratio attendant with its use."

The Bigger Context

These oral surgeons stress that these cases must be viewed in the
overall context of the many TMJ silicone implants that have been
implanted during past years with no untoward effects. They add that,
although "silicone may not be a totally inert material and its
biomechanical properties are not ideal for use in the TMJ," there is, in
fact, "no ideal material available."

It has been pointed out by many orthopedic surgeons that not only
silicone but all implant materials produce foreign-body giant cell
reactions. This includes stainless steel, titanium, ceramic,
polyethylene, Teflon, polypropylene, methyl methacrylate, and many other
materials.

Alfred Swanson, MD, Grand Rapids, Mich, inventor of the silicone finger
and wrist implants and an outspoken proponent of orthopedic implant
surgery, has written that "the foreign-body giant cell reaction is among
the most benign of inflammatory reactions that human tissues can mount
against an endless list of foreign materials."

"It is specious to conclude," he adds, "that any material that provokes
a foreign-body giant cell reaction must, per se, be abandoned as an
implant material. If such views prevailed, orthopedic implant surgery
would come to a precipitous halt [JAMA. 1983;250:1195-1198]."