ilena

So sorry to hear about what you are experiencing, Robert.

I've heard similar discussions from men with testicular implants
before ... here's something that our Amanda posted a couple of years
ago on this topic ... I'll see what else I can find.

~~~~~~~~~~~

I found 2.1.6 berry berry interesting also...

DRAFT GUIDANCE FOR PREPARATION OF PMA APPLICATIONS FOR TESTICULAR
PROSTHESES
Urology and Lithotripsy Devices Branch
Division of Reproductive, Abdominal, Ear, Nose and Throat, and
Radiological DevicesOffice of Device Evaluation
Center for Devices and Radiological HealthMarch, 1993
**********

2.1.3 Abrasion Resistance and ****ysis of
Abraded Surfaces of Solid Silicone and
Silicone Liquid-Filled or Gel-Filled
Testicular Prostheses
Silicone elastomers used in testicular
prostheses are relatively soft and are prone
to abrasive degradation at their surfaces.
While being placed in the incision in the
scrotum of a patient, a prosthesis is rubbed
against scrotal tissue. When the patient
moves, tissue or other anatomic structures
move over the prosthesis and/or its fibrous
capsule. Formation of a hernia or fold in
the shell in a filled device could
conceivably cause portions of the shell to
rub against itself. Rubbing actions such as
these can abrade the surface of the device.
Concern over abrasion is heightened when the
surface of the device is textured. Depending
upon the nature of the texturing process, the
topography of the surface may be either
regular or irregular. In either case, some
portion of the surface material will project
from the bulk material of the shell. Shear
stresses exerted on this projected surface
material will be greater since the shear
forces will be distributed over smaller
areas. Thus, when compared to smooth surface
material, textured surface material is more
prone to crack formation, tearing, and
abrasion for a given shear force.
Abrasion can lead to weakening of the device
surface making it more prone to mechanically
induced trauma. Abrasion can also release
small particles of silicone elastomer into
the body. These small particles can be
attacked by white blood cells which try to
digest the particles. However, because of
the relative inertness of the silicone
particles, they cannot be digested by the
white blood cells. Instead, the white blood
cells are destroyed (lysed) by the attempt to
digest the silicone, which can then result in
the formation of a mass of chronically
inflamed tissue (i.e., a silicone granuloma),
which must be surgically removed (Ref. 1).
If the particles are sufficiently small, they
can be transported to other regions of the
body where the same processes can produce
distant silicone granulomas.
In addition, the literature reports that
abrasion of a silicone elastomer can expose
the particles of silica added to reinforce
the elastomer (Ref. 2). Crystalline silica
is recognized as a sclerogen, i.e., an agent
which produces hard or sclerotic tissue,
capable of causing adverse reactions when
placed in the body (Ref. 3). Amorphous
fumed, rather than crystalline, silica is
typically used to reinforce the silicone
elastomers of these devices. However, there
are still concerns over the presence of
minute crystalline silica impurities in the
reinforcer and whether there is any
significant in vivo conversion of amorphous
silica into crystalline silica.
The abrasion resistance of the surface of the
silicone testicular prosthesis and the
particle size distribution of the material
abraded from the prosthesis must be known in
order to determine whether the device is safe
and effective. In order to respond to
unanswered questions concerning the adverse
effects of exposing silica in the body,
abrasion resistance testing, followed by
examination of the abraded surface for the
presence or absence of silica, must be
performed to determine whether a testicular
prosthesis is safe and effective.
Reports on abrasion resistance testing of
solid silicone testicular prostheses and
shell materials of liquid filled or silicone
gel-filled testicular prostheses must contain
relevant information on the equipment and
abrader used, identification and dimensions
of specimens, and detailed protocols. In
particular, a standard abrasion test machine,
or equivalent specialized equipment, must be
used to conduct the testing. In addition, a
complete description of the test apparatus
must be provided. A description of the
apparatus used, including the number of
specimens that can be tested simultaneously,
the dimensions (width and length) of both the
maximum sample size and the maximum abrading
area, and the manner in which specimens are
held, must also be provided. The material
used to abrade specimens must be identified,
and a rationale for choosing this material
must be provided as well. Properties of the
abrading medium including hardness,
roughness, etc., that are pertinent to the
abrasion process, also must be identified.
As usual, test specimens must be obtained
from shells of sterilized finished devices
manufactured according to the sponsor's
standard methods. Testing must be conducted
on each and every silicone elastomer
(comprising the outer surface of the device)
of all varieties of composition and surface
texture. Significant weight losses in
abraded material must be induced, and the
total number of passes (by the abrasive
medium) required to induce this observed
weight loss must be reported. Averages,
standard deviations, detailed protocols,
cycling rates, and raw data must be reported.
Examinations for exposed silica (particularly
crystalline silica) of both the abraded
surfaces and abraded particles from test
specimens must be conducted and reported.
Percentanges of crystalline silica and the
total content of crystalline silica in these
abraded particles must be ****yzed for and
reported. Particle size distributions of
abraded particles must be reported.
********
2.1.6 Silicone Bleed of the Shell and Patch
Materials of Silicone Gel-Filled
Testicular Prostheses
Silicone bleed permeation, which is the
seepage of silicone fluid components of the
internal gel fill through an intact shell of
a silicone gel-filled testicular prosthesis,
is one means by which the device can release
silicone into the human body. The body is
essentially a fluid receptacle for the liquid
silicone released by the device. As the
liquid silicone emerges from the shell, it
can dissipate into the body by at least two
mechanisms. The silicone bleed product can
be transported away from the device by simple
diffusion, that is, liquid flow in the
extracellular fluid as this fluid perfuses
the region adjacent to the surface of the
prosthesis. The bleed product can also be
taken up by white blood cells, primarily
macrophages in the tissues, and carried to
lymph nodes or other organs. Because the
liquid silicone is constantly removed from
the region of the prosthesis, the bleed
process cannot come to a halt. This results
in the body acting as an "infinite sink" for
the liquid silicone.
Determination of liquid silicone bleed rates
is particularly important in the case of
silicone gel testicular prostheses. A large
percentage of these devices are implanted in
infants. Thus, small quantities of silicone
bleed products may have proportionately
larger effects when body weights are small
and immune systems are not as fully developed
as in adults.
Steady-state diffusion coefficients for
silicone bleed permeation rates from silicone
gel-filled testicular prostheses must be
determined so that sound estimates can be
made of long-term ac***ulations of silicone
into a patient's body. These steady-state
diffusion coefficients must be determined for
individual components of the silicone bleed
as well. Silicone molecules in gel bleed
product have a range of molecular weights,
which cannot be assumed to be representative
of the range of molecular weights found for
molecules of silicone fluid in the gel inside
the device.
In fact, it is likely that silicone molecules
of smaller molecular weight possess higher
permeability rates through intact shells of
testicular prostheses than do silicone
molecules of higher molecular weight. Thus,
the composition of the bleed product is
likely, at any given time, to be skewed
toward lower molecular weight components in
comparison to the composition of the fluid
components of the gel inside the device.
These lower molecular weight silicone
molecules are also more likely to stimulate
biological activity. Therefore, accurate
assessments of the likelihood of long-term
toxicological response to an implanted
prosthesis (that remains intact) require
accurate dose rates of individual liquid
silicone components in the bleed, especially
those of the lowest molecular weights.
Various methodologies for performing liquid
silicone bleed permeation testing have been
used or proposed. Measured coefficients for
diffusion of components of liquid silicone
through a prosthesis are largely dependent
upon the receptacle medium used to collect
the bleed. It is possible to conduct the
experiment using either a solid-state medium
or a liquid-state medium. While, in general,
solid-state receptacles are easier to use,
there are major drawbacks associated with
them.
The major drawback to using a solid-state
medium is the potential for significant loss
of volatile silicones of low molecular
weight. Unlike a liquid receptacle diffusion
cell, the placement of a testicular
prosthesis on a disk or a filter is an
experimental system open to air or vacuum.
Substantial amounts of volatile silicones may
be lost (during the bleed experiment and/or
during subsequent extraction of the disk or
filter) and thus excluded from compositional
****ysis of the bleed product. Yet, as
explained earlier, it is vital that accurate
short-term and long-term dose rates of these
low molecular weight, volatile silicones be
established. Therefore, a liquid-state
receptacle medium must be used to conduct
liquid silicone bleed experiments in order to
adequately assess the potential risks
attributable to liquid silicone bleed from
silicone gel-filled testicular prostheses.
A stirred receptacle medium of physiological
saline is the best means of emulating actual
in vivo bleed rates. Stirring of the saline
medium is necessary to more accurately
account for the "infinite sink" conditions
which, as discussed earlier, exist in the
body. Stirring of the saline medium
transports a portion of the poorly soluble
silicones from the membrane surface such that
a concentration gradient in the vicinity of
the surface is maintained.