Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND APPARATUS FOR MONITORING IMPLANTS
BACKGROUND
[0001] The present invention relates to the field of medical devices. In
particular, the present
invention relates to monitoring for the integrity of implants (such as breast
implants)
implanted in tissues or organs.
[0002] The primary parts of most breast implants are a shell (also known as an
envelope or
lumen), a filler, and a patch to cover a manufacturing hole. Breast implants
may vary in shell
surface (e.g., smooth or textured), shape (e.g., round or other shape),
profile (i.e., how far it
projects), volume, area, and shell thickness. With respect to the shell
design, while most
breast implants are single lumen (i.e., one shell), some breast implants are
double lumen (i.e.,
one shell inside another shell). With respect to the filler, some breast
implants are
manufactured with a fixed volume of filler, some are filled during the
iinplantation operation,
and some allow for adjustments of the filler volume after the operation.
[0003] It should be noted that tissue expanders, which are silicone shells
filled with saline,
are regulated by FDA in a different way than breast implants. This is because
tissue
expanders are intended for general tissue expansion for a maximum of six
months, after
which, they are to be removed. Because of this, the design specifications
(e.g., thinner shell)
and preclinical testing recommendations are different for tissue expanders
than for breast
implants.
[0004] There are three types of silicone gel-filled breast implants: (1) a
single lumen implant
that is prefilled by the manufacturer with a fixed volume of silicone gel; (2)
a double luinen
implant with both an inner lumen prefilled by the manufacturer with a fixed
volume of
silicone gel and an outer luinen that is filled during the implantation with a
fixed volume of
saline through a valve; and (3) a double lumen inlplant with both an outer
lumen prefilled by
the manufacturer with a fixed volume of silicone gel and an inner lumen that
is filled during
the operation with saline through a valve that allows for adjustments of the
saline volume
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after the operation. The filler may be, e.g., silicone gel that has the
general composition of
silicone oil, cured polymeric (large) silicones, small amounts of uncured
large and smaller
silicones and minute amounts (i.e., parts per million) of metals, including a
metal catalyst
(e.g., platinum). This third type of breast implant is not to be confused with
a tissue
expander; The former being a permanent implant (i.e., not intended to be
removed) that
allows for limited tissue expansion, but is regulated by FDA as a breast
implant.
[0005] In 2001, the FDA published results in a study on the health effects of
ruptured silicone
gel breast implants. The FDA conducted this study because of concerns about
the frequency
and results of failure, rupture, breakage (hereinafter collectively
"failure"). Failure is a
concern because: (1) failure of silicone gel-filled implants may allow
silicone to migrate
through the tissues; (2) the relationship of free silicone to development or
progression of
disease is unknown; and (3) implant failure constitutes a device failure in
that the implant is
no longer performing as intended.
[0006] The study demonstrated that women with MRI diagnosed breast implant
failure were
no more likely than women with intact implants to report that they had either
persistent
symptoms or doctor-diagnosed illnesses that were listed. In addition, women
with MRI-
diagnosed extracapsular silicone gel (i.e., silicone that had migrated outside
the fibrous scar
around the implant) were 2.8 times more likely to report that they had the
soft tissue
syndrome, fibromyalgia. This association remained statistically significant
after taking into
account other factors including whether women thought their implants were
ruptured, implant
age, and implant manufacturer. Fibromyalgia is a syndrome characterized by
widespread
pain, fatigue, and sleep disturbance. Moreover, women with MRI-diagnosed
extracapsular
silicone gel were 2.7 times more likely to report that they had "other
connective tissue
disease," a category that included a diverse group of illnesses such as
dermatomyositis,
polymositis, and mixed connective tissue disease. This association did not
remain
statistically significant after taking into account other factors including
whether women
thought their implants were ruptured, implant age, and implant manufacturer.
[0007] Federal health advisers recently recommended that silicone-gel breast
implants be
allowed to return to the U.S. market after a thirteen year ban on most uses of
the implants, but
only under strict conditions that will limit access. The FDA can choose
whether to adopt or
reject this recommendation. The FDA's advisers said that Mentor Corporation, a
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manufacturer of silicone-gel breast implants, had performed more convincing
research that
indicated that only 1.4% of the implants break in the first three years after
implantation.
Mentor also showed some evidence that the implants may last as long as ten
years. The
FDA, however, stressed that sales should resume only if a manufacturer meets
certain strict
conditions, including: (1) that prospective patients sign consent forms that
acknowledge
implant risks, including that the implant ultimately may break and/or require
removal and/or
replacement; (2) that silicone implants are sold only to board-certified
plastic surgeons who
complete special training to insert implants in a way that minimizes the
likelihood of
breakage; (3) that data about patients receiving implants be maintained in a
registry to track
patients' long-term health; and (4) that formal studies be conducted to
ascertain more
definitively how often implants fail within ten years.
[0008] As implant failures typically do not cause immediate symptoms, it is
recommended
that implant patients receive, at minimum, an MRI scan five years post implant
and then
every two years thereafter. Patients should consider having broken implants
removed to
minimize risk of silicone oozing into the breast, or beyond. Currently, there
are no available
methods or systems for the monitoring of leakage of silicone from implants,
including breast
implants. MRI can be a useful tool for the detection of leakage, but there are
no signals.or
symptoms that indicate evaluation or monitoring should occur.
[0009] Numerous other implantable devices are currently used in medical
practice. One such
implantable device that is currently under consideration by the FDA for use in
the U.S. is the
BioEnterics Intragastric Balloon (BIB ) System, a non-surgical, non-
pharmaceutical
alternative for the treatment of obesity. The BIB System is designed to
induce temporary
weight loss in obese patients by partially filling the stomach to help them
achieve a feeling of
fullness.
[0010] Endoscopically placed within the stomach and inflated with saline, the
BIB System
balloon partially fills the stomach to induce a feeling of satiety to support
patients in reducing
food intake and adopting new dietary habits. Although the balloon can be
deflated and
removed endoscopically, it may improperly deflate during the course of
therapy. This
improper deflation may lead to migration of the implant into the intestine
with possible small
bowel obstruction and subsequent surgery and even death.
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[0011] Over time, bodily fluids are capable of passing into virtually any
implant, i.e., past
virtually any barrier. Even non-inflatable implants are susceptible to loss of
integrity
following implantation. Given enough time, even titanium shells permit passage
of bodily
fluids. In fact, recalls for pacemakers, ICDS and other implants commonly
occur due to
invasion of the implant by bodily fluids and subsequent malfunction;
malfunction of implants
in this category are frequently life-threatening.
[0012] U.S. Patent No. 6,755,861 describes a method of breast reconstruction
that uses a
breast prosthesis having a plurality of chambers or compartments distributed
through a body
member or shell in the form of a breast. The chambers are disposed along the
superior,
lateral, and inferior surfaces, as well as in the interior, of the body
member. The chambers
are differentially pressurized or filled, in order to control the shape of the
prosthesis upon
implantation thereof. Valves are provided for regulating the flow of fluid
into and from the
chambers. The prosthesis and the fill levels of the respective chambers may be
selected by
computer. This implant provides for a plurality of one-way valves, each
disposed between
two adjacent chambers for enabling a transfer of fluid from one of the
adjacent chambers to
anotlier of the adjacent chambers.
[0013] U.S. Patent No. 5,496,367 describes a breast implant that includes an
elastomeric
envelope adapted to contain a fluid material and baffles inside the envelope.
The baffles are
provided to reduce or dampen wave or ripple action and motion of the fluid
material
contained by the envelope when implanted in a breast.
[0014] U.S. Patent No. 4,795,463 describes a prosthesis for implantation into
human soft
tissue. This implant is constructed of a suitable implantable envelope and
contents (e.g.,
silicone gel, saline, or a combination of silicone gel and saline) to form a
breast shape when
implanted. The envelope is labeled with a marker that absorbs electromagnetic
energy to an
extent different from that of the envelope, its contents, and the human soft
tissue in the breast
cavity into which the prosthesis is implanted. This marker makes possible the
use of
roentgenographic imaging to determine whether the envelope has ruptured or
whether the
envelope is folded persistently in a particular location, thereby increasing
the probability that
the envelope may rupture along such a fold line. Also disclosed are: (a) a
method for using
roentgenography to determine whether the contents (e.g., silicone gel) have
escaped from the
envelope of the prosthesis by labeling the envelope with radioopaque
materials; and (b) a
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method for determining whether fold-fault failure of the envelope of the
implanted prosthesis
is likely to occur.
[0015] U.S. Patent Publication 2005/0033331 (published 02/10/2005) describes a
gastric
balloon implantation device that may incorporate a visible dye or marker to
enable detection
of device rupture.
[0016] U.S. Patent Publication 2005/0267595 (published 12/01/2005) describes a
gastric
balloon implantation device which includes as a leak monitoring system, a
sensor that
comprises a fine lattice or continuous film of detection material embedded in
the wall or in
between layers of the wall covering the entire device.
[0017] U.S. Patent Publication 2006/0111777 (published 05/25/2006) describes a
various
implantation devices including breast implants which include as a leak
monitoring system a
sensor that comprises a fine lattice or continuous film of detection material
embedded in the
wall or in between layers of the wall covering the entire device.
SUMMARY
[0018] Provided are devices for monitoring the integrity of implants, such as
breast implants.
These devices function to alert the user or a healthcare provider that the
integrity of the
implant is failing. The devices are useful for measuring leakage into and out
of the implant
as well as other parameters such as changes in pressure.
[0019] One embodiment of the present invention addresses a device for
monitoring a failure
in an external shell of an implant, following implantation in a user. This
device includes,
among other possible things: a sensor configured to detect a failure in the
external shell of
the implant; and a signaling element located in a lumen of the implant,
wherein the signaling
element is configured to be triggered by the sensor to alert the user or a
healthcare provider of
the failure.
[0020] Another embodiment of the present invention addresses a device for
monitoring a
failure in an external shell of a breast implant following implantation in a
user. This device
includes, among other possible things: a sensor configured to detect a failure
in the external
shell of the breast implant; and a signaling element located in a lumen of the
breast implant,
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wherein the signaling element is configured to be triggered by the sensor to
alert the user or a
healthcare provider of the failure.
[0021] Yet another embodiment of the present invention addresses a device for
monitoring a
failure in an external shell of a breast implant following implantation in a
user. This device
includes, among other possible things: a sensor configured to detect a failure
in the external
shell of the breast implant; and a signaling element located in a lumen of the
breast implant,
wherein the sensor is a conductive material present on the inside surface of
the external shell
and configured to be triggered by the sensor to alert the user or a healthcare
provider of the
failure.
[0022] A further embodiment of the present invention addresses a method of
monitoring for a
failure in an implant. This method includes, among other possible steps: (a)
providing a
device for monitoring a failure in an external shell of an implant, following
implantation in a
user, the device comprising: (i) a sensor configured to detect a failure in
the external shell of
the implant, wherein the sensor is a conductive material present on the inside
surface of the
external shell ; and (ii) a signaling element located in a lumen of the
implant; (b) monitoring,
using the sensor, physical conditions present within the lumen; (c)
determining, using the
sensor, that a failure of the implant has occurred based on changes in the
physical conditions
monitored by the sensor; (d) triggering the signaling element; and (e)
alerting, using the
signaling element, the user or a healthcare provider of the failure.
[0023] In any of the foregoing embodiments, the sensor may be configured to
detect a change
in conductivity.
[0024] Another embodiment for the sensor includes a thin electrical contact
liner coated on
the skin of an implant wherein the conductive layer has a larger surface area
or volume that
the lumen. This sensor may be triggered by any failure in the integrity of the
skin (or outer
layer) of the implant, detected tlirough changes in conductivity or other
properties associated
with the liner. The signal may be triggered by a breakage, stretching, or
displacement of any
of these wires.
[0025] Yet another embodiment of the present invention addresses an apparatus
that includes,
among other possible things: a sensor configured to detect a failure in an
external shell of an
implant following implantation in a user; a signaling element configured to be
triggered by
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the sensor to alert the user or a healthcare provider of the failure; and a
power source. At
least one of the sensors, the signaling element, and the power source is
configured to be
provided in a patch for the implant.
[0026] A further embodiment of the present invention addresses a method of
monitoring for a
failure in an implant. This method includes, among other possible steps: (a)
providing a
device for monitoring a failure in an external shell of an implant, following
implantation in a
user, the device comprising: (i) a sensor configured to detect a failure in
the external shell of
the implant; and (ii) a signaling element located in a lumen of the implant;
(b) monitoring,
using the sensor, physical conditions present within the lumen; (c)
determining, using the
sensor, that a failure of the implant has occurred based on changes in the
physical conditions
monitored by the sensor; (d) triggering the signaling element; and (e)
alerting, using the
signaling element, the user or a healthcare provider of the failure.
[0027] In any of the foregoing embodiments, the device may include a power
source for the
device which is contained within the device.
[0028] In any of the foregoing embodiments, the power source may be
rechargeable
transcutaneously.
[0029] In any of the foregoing embodiments, the device may include a energy
source that is
external to the device. Further, the device may be configured to receive power
transmitted
transcutaneously by the external power source.
[0030] In any of the foregoing embodiments, the sensor may be configured to
detect the
influx of bodily fluids and/or compounds.
[0031] In any of the foregoing embodiments, the sensor may be configured to
detect salinity,
hydration, pH, electrolyte concentration, or other properties of the bodily
fluids and/or
compounds entering the lumen.
[0032] In any of the foregoing embodiments, the sensor may be configured to
detect changes
to the environment inside the lumen.
[0033] In any of the foregoing embodiments, the sensor may be configured to
detect changes
in pressure, impedance, conductance or other physical property within the
lumen.
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[0034] In any of the foregoing embodiments, the sensor may be incorporated
into the external
shell or may not incorporated into the external shell.
[0035] In any of the foregoing embodiments, the sensor may be a mesh
incorporated
throughout shell.
[0036] In any of the foregoing embodiments, the sensor may be configured to
detect
alterations in the external shell based on electrical, chemical or physical
changes to the mesh.
[0037] In any of the foregoing embodiments, the sensor may be located external
to the shell.
[0038] In any of the foregoing embodiments, the sensor may be configured to
detect an
outflow of materials encased in the implant.
[0039] In any of the foregoing embodiments, the sensor may be configured to
detect clianges
in salinity, pH, hydration, chemical markers or other compounds.
[0040] In any of the foregoing embodiments, the power source may be a battery
or capacitor.
Further, the battery or capacitor may be configured to be inductively
recharged.
[0041] In any of the foregoing embodiments, the device may incorporate a
second signaling
element to alert the user that recharging is required. Further, the second
signaling element
may be a vibratory, acoustic, visual, tactile, electromagnetic field or other
stimulus.
[0042] In any of the foregoing embodiments, the signaling element may be
configured to
alert the user and/or healthcare provider upon triggering of the sensor.
[0043] In any of the foregoing embodiments, the signaling element may be a
vibratory,
acoustic, visual, tactile, or other stimulus.
[0044] In any of the foregoing embodiments, the signaling element may be
electromagnetic,
radiofrequency or ultrasound.
100451 In any of the foregoing embodiments, the device may incorporate a
receiver and/or
transmitter for external communication.
[0046] In any of the foregoing embodiments, the device may utilize ultrasound,
radiofrequency or electromagnetic fields for communication.
[0047] In any of the foregoing embodiments, the transmitter may externally
transmit data
relating to the implant.
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[0048] In any of the foregoing embodiments, the receiver may receive external
information.
Further, the received information may allow for programming, resetting or
other
manipulation of the device.
[0049] In any of the foregoing embodiments, the implant may be inflatable.
Further, the
device may be used to monitor the inflatable implant.
[0050] In any of the foregoing embodiments, the failure may be a rupture or
deflation of the
implant. Further, the user and/or healthcare provider may be alerted to
failure of the implant.
[0051] In any of the foregoing embodiments, the external shell may be rigid.
[0052] In any of the foregoing embodiments, circuitry within the implant may
allow for
external powering of the sensor and/or the signaling element via an external
power
source/signal transmitter.
[0053] In any of the foregoing embodiments, ground contacts for the circuitry
of the breast
implant may be located external to the shell.
[0054] In any of the foregoing embodiments, the external power source may be
supplied by
an external device placed witliin the living space of the user.
[0055] In any of the foregoing embodiments, the external power source may be
located
outside the user.
[0056] In any of the foregoing embodiments, the external power source may be
located
within or near a bed, couch, chair or seat of the user.
[0057] In any of the foregoing embodiments, the external power source may be
located
within accessories, clothing, personal items, house, car or workspace of the
user.
[0058] In any of the foregoing embodiments, the power source may be battery
and/or
capacitor powered. Further, the power source may be portable. In addition, the
battery
and/or capacitor powering the power source may be rechargeable.
[0059] In any of the foregoing embodiments, the power source may be powered by
a
standard wall outlet.
[0060] In any of the foregoing embodiments, the external powering may be
continuous when
the implant is within a predetermined range of the external power source.
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[0061] In any of the foregoing embodiments, the signaling may be continuous
when the
implant is within a predetermined range of an external signal transmitter.
[0062] In any of the foregoing embodiments, the external powering and/or
signaling may be
intermittent with at least weekly, at least monthly or at least yearly
interaction with the
implant.
[0063] In any of the foregoing embodiments, the sensor, the power source, the
signaling
element, and related circuitry may be provided in the lumen. Further, the
sensor, the power
source, the signaling element, and related circuitry may be provided in a
signal compartment
within the lumen.
[0064] In any of the foregoing embodiments, all of the sensor, the signaling
element, and the
power source may be configured to be provided in a patch for the implant.
[0065] In any of the foregoing embodiments, the implant may be a breast
implant.
Moreover, the patch may be configured to be housed within an inflation port of
the breast
implant.
[0066] In any of the foregoing embodiments, the implant may be a breast
implant and the
breast implant is radiolucent.
[0067] In any of the foregoing method embodiments, the step of monitoring,
using the
sensor, physical conditions present within the lumen may include monitoring
one or more of
a salinity, hydration, pH, electrolyte concentration, and other properties of
bodily fluids
and/or compounds entering the lumen.
[0068] In any of the foregoing method embodiments, the step of alerting, using
the signaling
element, the user or a healthcare provider of the failure may include
producing one or more
of a vibratory, acoustic, visual, tactile, and electromagnetic field.
[0069] In any of the foregoing method embodiments, the metliod may also
include the step of
recharging the device periodically. Further, the recharging of the device may
be performed in
conjunction with an external power source.
[0070] In any of the foregoing method embodiments, the method may also include
the step of
alerting the user and/or healthcare provider that the device needs to be
recharged.
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[0071] In any of the foregoing method embodiments, the method may also include
the step of
resetting periodically baseline levels for the physically conditions.
[0072] In any of the foregoing method embodiments, monitoring may be conducted
before
implantation of the device. In one such embodiment, monitoring is conducted
during
manufacturing of the device. In another embodiment, monitoring is conducted
just prior to
surgical implantation.
[0073] In any of the foregoing method embodiments, monitoring may be conducted
after
implantation of the device. In one such embodiment, monitoring is conducted
just after
implantation during the initial surgery.
[0074] As used herein, the term "shell" refers to the exterior portion of an
implant device
which functions to separate the interior contents from body tissue and fluids.
In a preferred
embodiment, the shell has a thicknesses of .002-.2 inches and a durometer
value of 20A-90A
for hardness.
[0075] As used herein, the term "lumen" refers to a cavity that is present
inside of the shell
of an implant.
[0076] As used herein, the term "patch" refers to a plug for an inflation
opening of an
implant, which plug generally defines a discrete region of increased durometer
and/or
thickness through which the implant may be inflated or filled. The inflation
patch is typically
formed from a much stronger silicone than the rest of the shell and is added,
usually by
vulcanization, to the remainder of the implant shell after the shell has been
fully
manufactured.
[0077] These and other features, aspects, and advantages of the present
invention will
become more apparent from the following description, appended claims, and
accompanying
exemplary embodiments shown in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0078] Figure 1 is a perspective view of an embodiment of an implant
monitoring device for
a fluid- or gas-filled iinplant according to the present invention;
[0079] Figure 2 is a perspective view of another embodiment of an implant
monitoring
device according to the present invention;
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[0080] Figure 3 is a perspective view of another embodiment of an implant
monitoring
device according to the present invention;
[0081] Figure 4 is a perspective view of another embodiment of an implant
monitoring
device according to the present invention;
[0082] Figure 5 is a perspective view of another embodiment of an implant
monitoring
device according to the present invention;
[0083] Figures 6A and 6B are perspective views of a breast implant function of
the implant
monitoring device shown in Figure 4;
[0084] Figures 7A-7C are perspective views of another embodiment of an implant
monitoring device according to the present invention in which the implant is
powered and/or
interrogated externally; and
[0085] Figure 8A is a perspective and enlarged view of another embodiment of
an implant
monitoring device according to the present invention whereas Figures 8B and 8C
are
perspective views of a function of the implant monitoring device shown in
Figure 8A in both
an intact state and a failure state, respectively, of an implant.
DETAILED DESCRIPTION
[0086] Presently preferred embodiments of the invention are illustrated in the
drawings. An
effort has been made to use the same, or like, reference numbers throughout
the drawings to
refer to the same or like parts.
[0087] The proposed implant monitoring device of this application serves as a
solution to the
issue of monitoring for leakage from, or leakage into, implants (such as the
BIB , breast
implants, pacemakers, implantable cardioverter defibrillators, and other
related devices). The
device described herein has the ability to sense and communicate the
occurrence of loss of
integrity in the shell of virtually any implant.
[0088] The innovation of the present invention involves a device and method
that
communicate, to the patient and healthcare professionals, the failure of a
barrier within an
implantable device. The implant monitoring device consists of an implantable
sensor and a
means of external communication. The sensor may be made of a conductive
material that
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may be either metallic or organic. For example, the sensor in some embodiments
may be
formed of gold.
[0089] The device may include an internal power source and may employ software
to allow
for programmability and/or interrogation of the device. The device may also be
recharged
and/or powered through an external source. Circuitry associated with the
sensor, the
signaling eleinent, external powering, and/or external interrogation may be
composed of
resistors and capacitors. Moreover, in certain embodiments (such as that later
described with
reference to Figures 8A-8C) the circuitry may be formed of resistors and
capacitors that are
printed onto a patch of the implant. The wireless communication to external
devices may be
done using RFID circuitry that may be printed on the patch.
[0090] In one embodiment, the sensor component of the device is able to detect
changes in
wall pressure, fluid pressure, pH, salinity, hydration, electrical fields,
etc. This device may
also detect disruption of the encasing meinbrane, the presence of specific
markers found in
surrounding body tissues, or other potential markers that are indicative of
failure. This ability
to detect changes in the integrity of an implant facilitates continuous
monitoring of the
implant, thereby enhancing the safety and integrity associated with the
implant.
[0091] An embodiment for the sensor includes a thin electrical contact liner
embedded in the
skin of an implant. This sensor may be triggered by any failure in the
integrity of the skin (or
outer layer) of the implant, detected through changes in conductivity or
otlier properties
associated with the liner. An alternative embodiment for the sensor mechanism
may involve
thin filament wires (or fibers of any type) placed in a meshwork throughout
the shell of an
implant. The signal may be triggered by a breakage, stretching, or
displacement of any of
these wires.
[0092] Another embodiment of the sensor includes a sensor/switch that is
triggered once
certain conditions are met, thus preserving the power within the implantable
power source for
signal generation. For example, two leads may be positioned within a space
that contains a
desiccated hydrophilic polymer, whicll may be coated by an aqueous barrier
that dissolves in
the presence of bodily fluids (e.g., ions, proteins, glucose, etc.). Once
introduced to bodily
fluids, the aqueous barrier may rapidly degrade, thereby exposing the
hydrophilic polyrner to
water. The water may cause the hydrophilic polymer to expand, thereby
connecting the two
electrodes and completing a circuit that causes the activation of the alert
mechanism.
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[0093] While not required for all applications, the aqueous barrier may be
more necessary for
any application in which the implant may be penetrated by water vapor. In
particular,
silicone-encased implants may be exposed to large amounts of water vapor (but
not ions)
within the implant. Thus, once the silicone shell ruptures and the aqueous
barrier (i.e., enteric
coatings or other coatings sensitive to bodily fluids) is rapidly compromised,
the hydrophilic
polymer may rapidly swell and close the circuit to generate the rupture alert.
In the absence
of such an aqueous barrier, at least in this instance, there may be a large
number of false
positives, due to water vapor causing expansion of the hydrophilic polymer. In
contrast, in
instances in which the shell of the implant is relatively impermeable to water
and other
vapors, the aqueous barrier coating may be unnecessary, thereby allowing for
the use of a
hydrophilic polymer (or other bodily fluid sensor). This is but one embodiment
of the present
invention; other embodiments exist in which the switch may be triggered by
changes in
salinity, pressure, pH, hydration, or other components found external to the
implant.
[0094] Once the sensor conditions have been met, the alert mechanism for the
device delivers
a device failure signal to the patient and/or healthcare professionals. The
alert mechanism
may be capable of communicating the occurrence of integrity failure for an
implant via a
plurality of different patient-centered stimuli, including visual stimulus
(e.g., activation of a
light visible through the skin), palpatory stimulus (e.g., vibration) or
auditory stimulus (e.g.,
emitting a beeping sound). The vibratory alert signal, for example, could be
either constant
or intermittent in nature and would be intended to be forceful enough not to
be mistaken for
other body sensations. This alert may be programmed to be sensed solely by the
patient (for
privacy concerns) and not to interfere with sleep, but, at the same time, not
to be easily
ignored. The triggering of this alert mechanism would signal to the patient
and/or a
healthcare professional that the device needs to be inspected. The device may
alternatively
communicate the existence of a failure to an external device via radio-
frequency or
electromagnetic fields. In those instances in which the power source is
internal and is
rechargeable, these signaling mechanisms may also be triggered to inform the
patient or the
healthcare provider that the device requires recharging.
[0095] In some embodiments of the present invention, the communication element
of the
device may provide for exchange of information with an external device. For
example, the
device may contain internal programming capabilities that allow for monitoring
of changes in
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the implant that might indicate a failure of the device while at the same time
adjusting a
baseline for monitoring these changes. This feature may be used as a safeguard
to ensure that
the patient is not subjected to unnecessary surgeries prompted by false
positives in instances
in which the device could have been safely reprogrammed externally.
[0096] An example of how this integrity monitoring device may work in a
silicone gel-filled
breast implant may be as follows. In the event that the outer silicone
envelope of a silicone
gel-filled breast implant fails, bodily fluids will enter the implant. The
ability of bodily fluids
to enter the implant may be enhanced by the addition of various coatings
(e.g., parylene,
heparin hydromer, etc.) or channels on the inside of, or within, the implant
shell. Thus, upon
failure of the shell, bodily fluids will come in contact with the sensor
(e.g., one or more
hydration monitors inside the shell of the implant). The aqueous barrier
(e.g., a pH-sensitive
Eudragit) covering the hydration sensors will rapidly degrade in the presence
of the bodily
fluids, thereby exposing the hydrophilic polymer to water. The polymer will
swell, thereby
forcing two electrodes into contact and completing a circuit that triggers the
alert signal (e.g.,
a small eccentric motor could draw power from a life-time battery and cause a
vibration in
the affected breast or alert the healthcare provider remotely).
[0097] Alternatively, the power source and signal may be outside of the
patient's body,
thereby allowing interrogation of the breast implant once it comes within
range of the
power/signal transmitter. Thus, by having a simple receiver/transmitter in the
breast implant
(e.g., an RFID chip within the implant or printed on the silicone shell of the
implant itself),
the present invention will: (a) have a minimal impact on the design of the
breast implant; (b)
be unlikely to be able to be palpated upon examination; and (c) function for
the life of the
implant (even with implants that last decades). In this embodiment, the
patient will simply
have to ensure that she comes in contact with the power/signal transmitter,
which could be
placed in the patient's home (e.g., at her bedside for daily or more frequent
checks) or in a
physician's office (for less frequent checks). The power/signal transmitter
could then contact
the physician or healthcare provider automatically and/or alert the patient.
In the event that
the patient is alerted, the previously trained and educated patient would then
contact a
healthcare professional to have her device interrogated (i.e., to have an MRI
or other
appropriate investigation initiated) and/or to have surgery to remove the
implant. As a result,
a patient would know relatively immediately about failure of a device and
would not have to
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16
wait, in some cases up to five years or more, to have a regularly scheduled
MRI. The
embodiments of this device may be externally-powered, may incorporate a
battery that could
be rechargeable in nature, or may incorporate a battery that has a life-time
functional
expectancy (i.e., having a very-low-current-draw sensor or a zero-current-draw
switch
activated device).
[0098] The device of this application has the capability of being used with
any implantable
technology. Although breast implants are specifically mentioned as examples in
this
application, the nature of this device makes it applicable to all forms of
implants. In
particular, the use of this technology within implantable gastric balloons is
readily
appreciated. In such gastric embodiments, as with the breast implant
embodiments, one
scenario involves the use of an external power/signal generator that
communicates with a
receiver/transmitter (e.g., an RFID chip) associated with the shell of the
gastric implant. The
receiver/transmitter (e.g. an RFID chip) may be located within the shell,
printed on the
outside of the shell, attached to the inside wall of the shell, or located in
the lumen of the
shell but not attached to the shell wall. Thus, modifications and alterations
to the design and
function of the gastric balloon can be minimized with the use of an external
power/signal
generator. These options also are applicable to breast or other types of
implants.
[0099] In this embodiment, as well, the gastric balloon may be inflated with a
solution that is
non-conductive (or at a minimum is less conductive than normal saline) but
osmotically
active. Thus, upon ingress of bodily fluids into the failing implant, as in
the case of the breast
implant, the conductivity across the electrodes within the implant (or printed
on the inside of
the shell of the implant) will be altered; this information will be
transmitted externally via the
RFID mechanism coupled to the electrodes. This mechanism has been validated by
the
inventors in a protocol that found that the capacitance of a solution of
deionized water is on
the order of picofarads across electrodes spaced five millimeters apart, while
normal saline
capacitance across this gap is on the order of 10 to 100 nanofarads (a 1000-
fold difference).
The relationship is nearly linear such that even a small amount of saline or
gastric fluid is
capable of registering a significant difference in capacitance or
conductivity, which may be
transmitted via the coupled RFID electronics. Thus, by filling the implant
with psyllium fiber
(or another osmotically active, FDA-cleared substance that is either more or
less conductive
than normal saline or gastric secretions), the conductivity, capacitance,
resistance, etc. across
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the electrodes within the implant may be checked intermittently (or
continuously). Further, if
a change in any of these parameters is found, the device may be rapidly
replaced prior to
dangerous passage into the intestine.
[0100] The present invention may also be used in the gastric space or other
space using any
of the embodiments previously discussed with respect to the breast implant
technology.
However, in any technology in which the implanted device is inflated at the
time of the
procedure, the present invention contemplates a significant advance in the use
of a fluid with
a conductivity, resistance, or capacitance which deviates from that of normal
saline or bodily
secretions in order to use the electrodes to measure the change in electrical
paraineters in the
detection of implant failure. Unfortunately, devices that are currently
inflated inside the body
(e.g., gastric balloons, breast implants, etc.) are typically filled with
saline, which removes
the benefit of simple detection of changes in electrical parameters found with
the ingress of
saline into a more or less electrically active fluid medium. Furthermore, the
filling fluid may
also be significantly different with respect to the chemical, optical,
physical, pH, and/or
electrical properties of normal saline and/or the fluid surrounding implant
such that these
parameters may be sensed within the implant as well. Changes to any one of
these, or other,
parameters within the implant may indicate failure of the external implant
barrier.
[0101] The present invention may also use scaffolding and/or other support
structures in
combination with the aforementioned failure sensing technologies. Some such
scaffolding
and support structures are disclosed in U.S. Patent Publication 2005/0033331
(published
02/10/2005) (U.S. Patent Application No. 10/833,950, which is entitled
"Pyloric Valve
Obstructing Devices and Methods" and which was filed on April 27, 2004). The
support
structures disclosed in U.S. U.S. Patent Publication 2005/0033331, which is
hereby
incorporated by reference in its entirety, may ensure that the device does not
deflate and
cause problems (e.g., intestinal obstruction in the case of the gastric
balloon) in the event of a
catastrophic failure and/or rapid leak. An embodiment of such a support
structure may
additionally allow for rapid collapse of the device with standard endoscopic
tools, thereby
providing a significant advance over the current removal procedures with the
gastric balloon.
By using a scaffold, which may be easily engaged and collapsed by endoscopic
snares,
forceps or scissors, the device may be extracted without the need for
cumbersome and
unwieldy puncturing, which is typically necessary with current gastric balloon
removal.
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[0102] The competitive advantages of this integrity monitoring system for long-
term
implants include: (1) continuous (or intermittent but frequent) monitoring of
implant
integrity; (2) an implant failure signaling mechanism for both the patient and
healthcare
professional; and (3) the ability to have a sensor communicate, with an
external device,
information about the state of an implanted device.
[0103] Figure 1 is an illustration of an implant integrity monitoring device
100 for a fluid- or
gas-filled implant 103. As can be seen in this embodiment, a sensor 101, a
signaling or
alerting element 102, and other electronics (not labeled) are incorporated
into an internal
element 1 that is housed within an open space or cavity defined by an exterior
she114 of the
implant 103. As a result, the sensor 101 of this embodiment is not provided as
a continuous
film or as a mesh on the shell 4.
[0104] The shell 4 may include an optional injection/inflation patch 5 for
implants designed
to be placed within the body and then filled. The patch 5, which is designed
to plug an
inflation opening, generally defines a discrete region of increased durometer
and/or thickness
through which the implant 103 may be inflated or filled.
[0105] As shown, the device 100 may also include an optional
communicating/inductive
charging ring 2 and a connecting tether 3 that connects the charging ring 2 to
the internal
element 1. The internal element 1 senses and communicates externally if there
has been a
failure of the shell 4. The sensor 101 may detect changes in salinity, pH,
pressure, presence
of certain compounds, or any other change in the internal milieu once the
external shell 4 has
been compromised. The signaling element 102 within the internal element 1 may
vibrate,
communicate to an external device (not shown), make an audible noise, or emit
a light to
indicate that a check is required to ensure integrity of the she114. The
signaling element 102
may also alert the user that recharging of her device 100 is required in those
embodiments in
which the device 100 is internally powered. In both the internally and
externally powered
embodiments, the device 100 may communicate externally and be
programmable/resettable
such that if it is triggered without a failure of the shell 4, it can simply
be reset to continue
monitoring.
[0106] Although the device 100 is shown monitoring an implant 103 having a
spherical shell
4 (as would be the case for many breast implants and gastric balloons), this
is but one
embodiment of the device 100 and other embodiments contemplate non-spherical
shapes.
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Moreover, the device 100 may be adapted to monitor implants in any area of the
body and
may be made of any material.
[0107] The sensor 101 within the internal element 1 may be one or more of a
variety of
sensors including sensors for detecting changes in: salinity, pH, hydration,
chemical markers
(or other compounds), pressure, impedance, conductance, or other physical
properties within
the monitored device. Moreover, the sensor 101 itself may use electric,
spectrophotomoteric,
chemical or physical measurement technologies.
[0108] Alternatively, the device 100 may use a passive sensor that will not
require active
measurements of the internal milieu, but instead will remain dormant until the
appropriate
conditions are met (i.e., until a failure of the implant 103 occurs). Two
examples of this are
pH- and/or ion-sensitive polymers. The polymers may swell, degrade, or alter
their physical
properties in some manner that allows electrodes to come in contact with each
other, thereby
signaling a failure of the implant 103. An embodiment of this design may
involve the use of
a pH-sensitive compound (e.g., a pharmaceutical enteric coating) that is
placed between the
electrodes of the alerting element 102 and remains there until aqueous fluid
enters the implant
103. At this point, the polymer degrades and the electrodes come into contact.
When the
electrodes contact each other, the user is alerted to a failure. Two examples
of a material that
could be used for this application are Eudragit (Rohm and Haas) and Opadry AMB
(Colorcon). These are but two examples and this is but one embodiment of the
many
possible embodiments of the envisioned sensor 101. The only requirement is
that the sensor
101 be resistant to compounds normally found within the monitored device
(e.g., water
vapor), but be triggered upon influx of abnormal materials (e.g., ions or
proteins).
[0109] The alerting element 102 within the internal element 1 may be one or
more of a
variety of possible signal generating devices including physical stimuli
generators and/or
energy or electromagnetic communicators. Among the possible physical stimuli
are:
auditory (e.g., a sound), visual (e.g., a light under the skin) and tactile
(e.g., a vibration).
Further, it is noted that vibration, which may be essentially soundless, may
satisfy both
privacy concerns and the desire to communicate robustly. In the case of
vibration, a small
eccentric motor, piezoelectric element or very low-range acoustic element may
be used to
generate the intended vibration. Any source of vibration or energy-delivery
could be used,
though, with the only requirement being that the patient be sufficiently
alerted.
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[0110] The alert may be activated during certain time periods, over intervals,
or with a
unique signal to indicate device conditions. For example, in the case of a
rechargeable
device, if the device requires recharging, the alert may be of a certain
nature so as to indicate
that the battery is low, as opposed to a signal for implant failure. Moreover,
once alerted, the
healthcare provider may, in one embodiment, be able to interrogate the device
100 and even
reprogram the sensitivity threshold in the instance of a sensor 101 with a
slow baseline drift.
[0111] In the case of a device without an internal battery, the alerting
element 102 and/or
sensor 101 may be powered externally via inductive, RF or EMF energy
generation to
provide for intermittent, non-continuous interrogation of the device 100. The
interrogating
device (not shown) may be an office-based device for routine checks or a home-
use device
designed to interrogate the device 100 automatically and to report (to the
user or healthcare
provider) that the implant 103 has failed. Placement of the interrogating
device in an area in
which the patient can interact with it on a daily basis will allow for
regular, but intermittent,
interrogation of the device 100 with subsequent rapid reporting. This
reporting could, again,
be a local activity signaling the user, or could be directly transmitted to
the healthcare
provider to allow for immediate action.
[0112] Figure 2 is an illustration of another embodiment of an implant
integrity monitoring
device 200. As can be seen in this embodiment, in contrast to the design of
Figure 1, the
sensor 101 is not part of the internal element 1 and is instead incorporated
into a mesh 6 of
the implant 103. The mesh 6 may be incorporated into the she114, may be just
inside the
shell 4, or may be just outside of the shell 4. The signaling element 102,
circuitry and all
electronics other than the optional coinmunicating/inductive charging ring 2
and the
connecting/recharging tether 3 are still incorporated into an internal element
1. However, the
tether 3 may be used to transfer information between the sensor 101 within the
mesh 6 and
the internal element 1(which can actually be located anywhere within the shell
and does not
need to be centrally located). In this embodiment, alterations to the external
shell4 can be
detected by changes in volume, impedance, conductivity, magnetic field, etc.
which may
arise as a result of a break in the sensing mesh 6.
[0113] Figure 3 illustrates another embodiment of an implant integrity
monitoring device 300
in which sensors 7 are interspersed throughout a shell 4 of the implant 103.
The internal
element 1 may contain a power source 104, an external communication component
105,
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and/or a signaling or alerting element 102. Moreover, the internal element 1
may
communicate with the sensors 7 in the external shell 4 via a
communicating/recharging tether
3. Alternatively, and this goes for all embodiments, the internal element 1
may be affixed to
the internal surface of the shell 4 of the implant 103 at one or more points
requiring little, or
even no, tether. The sensors 7 inside of, or within, the shell 4 may detect
influx of external
components from tissue (e.g., breast tissue) surrounding the implant 103. For
example, the
sensors 7 may be hydration sensors or salinity sensors. Alternatively, the
sensors may be pH,
conductivity, impedance, light, or chemically-based. There may also be
multiple sensors 7 in
regions of high-risk (e.g., the inflation patch and/or manufacturing seam(s)).
Once again, this
is but one embodiment of the present invention and it may be adapted to
monitor implants in
any area of the body and may be made of any material.
[0114] Figure 4 illustrates another embodiment of an implant integrity
monitoring device 400
according to the present invention. Although sensing element 101,
communicating element
105, and alerting element 102 may be separately provided throughout the
implant 103, they
may, as shown, be incorporated into one internal element 1. This internal
element 1
communicates with the optional coinmunicating/recharging ring 2 via a
recharging tether 8
that has additional properties. In this embodiment, the tether 8, also
channels fluid from the
inside of the shell 4 to the sensing element 101 within the internal element
1. Further, the
inside of the shell 4 may also be coated with a coating material 9 designed to
bring the sensed
substance to the sensing element 101 within the internal element 1. The
coating material 9
may be, e.g., parylene or heparin hydromer and may be designed to carry the
ionic bodily
fluid to the sensor element 101 at which the ion- or pH-sensitive sensor
element 101 may be
triggered, thereby alerting the patient and/or healthcare provider of an
implant failure. This
design will be particularly useful for indications in which the filling of the
implant 103 is
relatively impervious to the substance being sensed. A good example is the
silicone gel
breast implant, which, when filled with silicone gel 10, discourages influx of
any aqueous
material. The internal coating material 9, though, allows the aqueous fluids
to track around
the gel 10 to the tether 8 from which the fluids may be carried to the sensor
element 101
within the internal element l.
[0115] The coating material 9 may consist of any one or more of a variety
materials,
including, as previously mentioned, parylene and/or heparin hydromer. These
compounds
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may coat tracks within the silicone shell 4 (assuming the breast implant case)
or may coat the
entire inside of the shell 4. This will help to generate a potential space
between the ge110
and the she114 (in the case of parylene) and/or to attract aqueous fluid due
to hydrophilicity
(in the case of hydrophilic polymers such as the heparin hydromer coating).
Whether
drawing the fluid around to the sensor element 101 or creating a plane for the
fluid to track
within, either mechanism could be used if the desired rate of fluid ingress is
not found to
occur of its own volition in an unmodified implant 103.
[0116] Figure 5 illustrates another embodiment of an implant integrity
monitoring device
500. In this embodiment, the device 500 is incorporated into an internal
element 1 that is
provided adjacent an external shell of an electronic device 11. As shown, the
device 500 is
minimized to allow for incorporation into a small space from which the device
may monitor
the electronic device 11, which could be, e.g., a pacemaker, an implantable
pump,
implantable glucose sensor, an implantable cardioverter defibrillator, an
implantable left
ventricular assist device, or any other implantable device with electrical
components.
[0117] Figures 6A and 6B illustrate the action of an implant 103 (e.g., a
breast implant) and
the implant integrity monitoring device 400 from Figure 4. The implant 103 is
shown with a
failure (e.g., a rupture) 12 in its she114. The failure 12 allows fluid 13 to
track around the
inside of the shell 4 along the optional coating material 9 to the sensor
element 101 within the
internal element 1 via the optional tetlier 8. Once the fluid 13 has made it
way from the site
of the rupture 12 to the inside of the implant 103 and reaches the internal
element 1, the
sensor element 101 (which may be, e.g., a pH or salinity sensor) is triggered
due to its
exposure to the constituents within bodily fluid 13. Once the sensor element
101 is triggered,
the signaling or alerting element 102 (which maybe, e.g., an eccentric motor)
may, as shown
at label 14 in Figure 6B, vibrate rapidly. This is but one-of several alerting
mechanisms with
auditory signals, visual signals, and radio communication being three other
possibilities.
These are exemplary illustrations, though, and should not be interpreted to be
the only
possible embodiments.
[0118] Figures 7A-7C illiiustrate perspective views of the function of an
implant integrity
monitoring device 700 for breast implants in which the implant 103 is powered
and/or
interrogated externally. In this embodiment, a power and/or signal
emitter/receiver 16 emits
a radiofrequency or electromagnetic waves 17 to power and/or communicate with
the implant
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103. In turn, the internal element 1 of the device 700 emits a signal 18, 19
in response to the
power and/or signal emitter/receiver 16. This signal 18, 19 may then be
interpreted by the
power and/or signal emitter/receiver 16, thereby alerting the user and/or
healthcare provider
of changes in the monitored implant such as a failure 13. In the case of a
failure 13 of the
external shell 4, bodily fluid 15 will track to the internal element 1.
[0119] In response to the bodily fluid 15, the internal element 1 will emit a
signal to the
power and/or signal emitter/receiver 16 to inform the user and/or healthcare
provider that the
implant 103 has been compromised. A breach will be evident based on the
cllange in the
signal from a normal signal response 18 (Figures 7A and 7B) to that of a
compromised
implant signal response 19 (Figure 7C). In response to the signal from the
power and/or
signal emitter/receiver 16, the responsive signal 18, 19 may be generated by
an active
mechanism such as, e.g., an active RFID tag or other EMF, ultrasound or
radiofrequency
emitter, or may be generated by a passive mechanism such as, e.g., a passive
RFID tag.
[0120] The power and/or signal emitter/receiver 16 may be designed to interact
intermittently
with the internal element 1 or may monitor the internal element 1 on a
continuous basis. In
some embodiments, the power and/or signal emitter/receiver 16 may be placed
within the
home of the implant patient in an area that she will frequent at least once
per day. For
example, the power and/or signal emitter/receiver 16 may be placed in, or
near, a bed, chair,
car, office, table or any other object or region that the implant patient will
frequent on a daily
basis. Moreover, the power and/or signal emitter/receiver 16 may be powered by
battery,
capacitor, or wall outlet and may be fixed in place or easily portable. From
there, the power
and/or signal emitter/receiver 16 will interact with the implant integrity
monitoring device
700 and receive the signal 18, 19 from the device 700 to determine if the
implant 103 has
been compromised, as shown in Figure 7C.
[0121] In the event that the implant 103 is inflated within the body (e.g.,
for breast implants
or and/or gastric balloons) the implant 103 may, as shown, be filled with the
optional filling
fluid 20 of known conductivity, capacitance, resistance and/or other
electrical properties that
vary significantly from normal saline and/or the bodily fluid 15 surrounding
the implant 103.
Thus, by using the internal element 1 to measure the electrical properties of
the filling fluid
20 and to detect variations in these properties upon mixing of the filling
fluid 20 with bodily
fluids 15, a failure 13 in the external shell 4 may be sensed and
communicated.
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[0122] As previously shown and discussed, in inflatable fluid- or gel-filled
implants, there is
typically an inflation patch 5 somewhere on the implant. This inflation patch
5 is typically
formed from a much stronger silicone and is added, usually by vulcanization,
to the
remainder of the implant shell 4 after the shell 4 has been fully
manufactured. A simpler,
alternative embodiment to such a structure involves modifications only to this
inflation patch
and no modifications to the silicone shell 4. However, tracking of bodily
fluids through
silicone gels filling such a structure is limited whereas tracking of bodily
fluid and ions
through hydrogels filling such a structure occurs readily. As a result, a
solution for a implant
with a non-conductive filling (e.g., silicone gel) would likely require
modification to the
entire shell 4. This process, however, is laborious and provides a future risk
of failure (e.g.,
from perforation or rupture) due to the added elements in the shell 4 that
either encourage
tracking of the fluid or conduct signals from the failure to the communication
patch at the
back of the implant.
[0123] An alternative option for any device filled with saline or another
conductive fluid that
is much more reliable with inuch less added risk of rupture, is to incorporate
the entire
implant integrity monitoring device within the patch 5 of the implant. This is
possible due to
the nature of the conductive filler (e.g., saline or other material), in that
the sensor requires
only: (a) a contact point on the inside of the she114, which can be on the
patch 5 or free-
floating with a connection to the patch 5; and (b) an external contact point,
which can simply
be a small electrically conductive region on the outside of the implant. In
such embodiments,
the only modification to the implant would be required at the patch 5 (and
possibly within the
filler). Moreover, no modification would be need to be made to the shell 4 at
which any
modif cation may increase the risk of failure. An embodiment of such a patch
will hereafter
be described with reference to Figures 8A-8C.
[0124] Figure 8A is a perspective and enlarged view of the injection patch 5
of a fluid- or
gel-filled implant 103. The implant 103 is filled with a conductive material
in which the
sensing and communicating components (e.g., an RFID chip) of the iinplant
integrity
monitoring device 800 are incorporated within the injection patch 5 as a chip
804, i.e., the
shell is unmodified. In the enlarged portion of Figure 8A, an external
electrical contact point
802 can be seen incorporated into the standard injection patch 5. This
external electrical
contact point 802 is in electrical communication with the electrical sensing
and
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communicating chip 804 via electrical connections 806 spanning and across the
patch 5.
[0125] As can be seen in Figure 8B, in the presence of an intact shell 4, the
electrical impulse
released into the conductive filling media 810 inside of the implant 103 by
the sensing and
communicating chip 804 is exposed to an open circuit due to the insulating
properties of the
intact shell 4. As a result, none of the electrical impulse is transmitted to
the external
electrical contact point 802.
[0126] In contrast, as can be seen in Figure 8C, in the presence of a shell 4
that has a failure,
the electrical impulse released into the conductive filling media 810 inside
of the implant 103
by the sensing and communicating chip 804 is in electrical communication with
the
conductive bodily fluids 812 outside of the implant. As a result, the electric
impulse is
transmitted to the external electrical contact point 802. As the external
electrical contact
point 802 is in electrical communication with the sensing and communicating
chip 804 (via
an electrical connection 806 spanning the patch 5), the now closed circuit
allows the sensing
and communicating chip 804 to receive the impulse from the external electrical
contact point
802 and, therefore, to report a failure.
[0127] The patch only modification found in Figures 8A-C may be used with the
silicone gel
embodiment by modifying the silicone gel to render it conductive (through the
addition of
metals, organometals, or other charge-carrying molecules to the silicone gel).
Alternatively,
the circumference of the silicone gel mass (at the gel-shell interface) may be
made conductive
while the central gel may be the standard, non-conductive gel. This may be
accomplished
through a two step gel insertion process whereby the outer rim of conductive
gel is placed
and cured (or partly cured) prior to instillation and curing of the remainder
of the non-
conductive silicone gel. This approach will minimize the conductive silicone
gel required
and will provide a superior solution compare to conductive layers or meshes
within the shell
in that the silicone gel emanating from the tear will not coat and insulate
the conductive layer
if it is the conductive layer itself. In addition to the standard dip-molding
of the shell and
injection of the silicone gel, the layered and/or conductive silicone gel
approach could also be
manufactured using single or multiple shot molding processes. In this
embodiment, the
device may or may not be radiolucent.
[0128] While the embodiment shown in Figures 8A-8C is shown as being used with
a
silicone device with a shell 4 and conductive filling media 810, the implant
integrity
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26
monitoring device 800 could also be used with any implant 103 that has a non-
conductive
shell 4. For example, in the instance of a pacemaker or implantable
cardioverter defibrillator,
the device 800 could be used in the titanium shell of the implant near the
most likely point of
fluid ingress. The device 800 may then be interrogated routinely to determine
if the shell has
been compromised via the detection of the ingress of conductive bodily fluids.
Further, while
the embodiment shown in Figures 8A-8C has been described as being fully
incorporated into
the patch of the implant, some element of the device 800 may be included
within the implant
or within the external milieu (e.g., in the manner of the tethers of
embodiments shown in
Figures 1-4), so long as an external communication exists across the implant
shell 4. Finally,
whereas the embodiment shown in Figures 8A-8C is described as monitoring an
internal
conductivity of the fluid 810 within implant 103, other embodiments of the
present invention
envision simultaneously monitoring both the fluid 810 within the implant 103
and the fluid
812 outside of the implant 103 to determine the presence or absence of a
complete
conducting pathway across the shell 4 of the implant 103.
[0129] The present invention has been envisioned as being highly useful for
any inflatable
implant, including breast implants, percutaneous gastrostomy tubes, Foley
catheters, penile
implants, gastric balloons, etc. Further, due to the relative ease of
measuring electrical
properties and relative ease of translation to an RFID-based technology, the
internal element
1 could be reduced significantly in size or even simply encompass an RFID and
electrical
property sensing element that are printed on the inside of the implant to be
monitored. In this
way, changes in electrical properties can be quickly and easily measured and
reported in a
very low-profile manner within the implant. This feature may also apply to
other
characteristics of the filling fluid including chemical, optical, physical,
pH, electrical
properties, etc.
[0130] Lastly, while RFID has been mentioned as a communicating mechanism, a
variety of
other mechanisms may be employed including auditory, acoustic, vibrational or
other stimuli
to alert the patient that the implant has been compromised. Also, while RFID
has also been
mentioned as a method of powering the device, the device may also be powered
by
alternative mechanisms, including a self-winding mechanism (as found in
watches), an
internal rechargeable battery, or a long-lasting capacitor/internal battery.
These alternative
charging and alerting mechanisms all provide for an additional safeguard in
that the patient
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may be notified nearly instantaneously of a rupture and not require the
additional step of
exposure to an RFID transmitting/receiving apparatus.
[0131] All patents and publications mentioned in the specification are
indicative of the levels
of those of ordinary skill in the art to which the invention pertains. All
patents and
publications are herein incorporated by reference to the same extent as if
each individual
publication was specifically and individually indicated to be incorporated by
reference.
[0132] The invention illustratively described herein suitably may be practiced
in the absence
of any element or elements, limitation or limitations which is not
specifically disclosed
herein. Thus, for example, in each instance herein any of the terms
"comprising," "consisting
essentially of' and "consisting of' may be replaced with either of the other
two terms. The
terms and expressions which have been employed are used as terms of
description and not of
limitation, and there is no intention that in the use of such terms and
expressions of excluding
any equivalents of the features shown and described or portions thereof, but
it is recognized
that various modifications are possible within the scope of the invention
claimed. Thus, it
should be understood that although the present invention has been specifically
disclosed by
preferred embodiments and optional features, modification and variation of the
concepts
herein disclosed may be resorted to by those skilled in the art, and that such
modifications
and variations are considered to be within the scope of this invention as
defined by the
appended claims.
[0133] Other embodiments are set forth within the following claims.
