Note: Descriptions are shown in the official language in which they were submitted.
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STATIC DEVICES AND METHODS
TO SHRINK TISSUES FOR INCONTINENCE
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of priority from Provisional U.S. Patent
Application Serial No. 60/094,946, filed July 31, 1998, and is a Continuation-
in-Part of
U.S. Patent Application Serial No. 09/170,767 filed October 13, 1998, the full
disclosures
of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to medical devices, methods and
systems for selectively contracting tissues, particularly for the treatment of
urinary
incontinence.
Urinary incontinence arises in both men and women with varying degrees
of severity, and from different causes. In men, the condition most frequently
occurs as a
result of prostatectomies which result in mechanical damage to the urethral
sphincter. In
women, the condition typically arises after pregnancy when musculoskeletal
damage has
occurred as a result of inelastic stretching of the structures which support
the
genitourinary tract. Specifically, pregnancy can result in inelastic
stretching of the pelvic
floor, the external sphincter, and the tissue structures which support the
bladder and
bladder neck region. In each of these cases, urinary leakage typically occurs
when a
patient's abdominal pressure increases as a result of stress, e.g., coughing,
sneezing,
laughing, exercise, or the like.
Treatment of urinary incontinence can take a variety of forms. Most
simply, the patient can wear absorptive devices or clothing, which is often
sufficient for
minor leakage events. Alternatively or additionally, patients may undertake
exercises
intended to strengthen the muscles in the pelvic region, or may attempt a
behavior
modification intended to reduce the incidence of urinary leakage.
In cases where such non-interventional approaches are inadequate or
unacceptable, the patient may undergo surgery to correct the problem. A wide
variety of
procedures have been developed to correct urinary incontinence in women.
Several of
these procedures are specifically intended to support the bladder neck region.
For
example, sutures, straps or other artificial structures are often looped
around the bladder
neck and affixed to the pelvis, the endopelvic fascia, the ligaments which
support the
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bladder, or the like. Other procedures involve surgical injections of bulking
agents,
inflatable balloons, or other elements to mechanically support the bladder
neck.
An alternative surgical procedure which is performed to enhance support
of the bladder is the Kelly plication. This involves midline plication of the
fascia,
particularly for repair of central defects. In this transvaginal procedure,
the endopelvic
fascia from either side of the urethra is approximated and attached together
using silk or
linen suture. A similar procedure, anterior colporrhaphy, involves exposing
the
pubocervical fascia and reapproximating or plicating portions of this tissue
from either
side of the midline with absorbable sutures. While the Kelly plicatiori~dnd
its variations
are now often used for repair of cystocele, this procedure was originally
described for the
treatment of incontinence.
Each of these known procedures has associated shortcomings. Surgical
operations which involve midline plications or direct suturing of the tissues
of the urethra
or bladder neck region require great skill and care to achieve the proper
level of artificial
IS support. In other words, it is necessary to occlude or support the tissue
sufficiently to
inhibit urinary leakage, but not so much that intentional voiding is made
difficult or
impossible. Balloons and other bulking agents which have been inserted can
migrate or
be absorbed by the body. The presence of such foreign body inserts can also be
a
source of urinary tract infections.
Alternative devices, systems, and methods for treatment of urinary
incontinence have recently been proposed in U.S. Patent Application No.
08/910,370,
filed August 13, 1997, and assigned to the assignee of the present invention.
This
reference, which is incorporated herein by reference, describes techniques for
treating
urinary incontinence by applying sufficient energy to tissue structures that
comprise or
support the patient's urethra so as to cause partial shrinkage of the tissue,
and thereby
inhibit incontinence. Hence, these techniques generally involve selectively
contracting a
patient's own pelvic support tissues, often applying gentle heating of the
collagenated
endopelvic structures to cause them to contract without imposing significant
injury on the
surrounding tissues. U.S. Patent Application No. 081910,775, filed August 13,
1997,
describes related non-invasive devices, methods and systems for shrinking of
tissues
and is also incorporated herein by reference.
While these new methods for treatment of incontinence by selectively
contracting tissues represent a significant advancement in the art, still
further
improvements would be desirable for treating urinary incontinence in men and
women.
In particular, it would be desirable to provide devices and therapies to
reliably and
repeatably contract tissues so as to effect the intended physiological change.
It would
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be best if these improved techniques and structures could provide reliable
results
independent of the normal variations in the skill and experience of the
surgeon. It would
further be desirable if these improved techniques could be performed using
minimally
invasive techniques so as to reduce patient trauma, while retaining and/or
enhancing the
overall efficacy of the procedure.
2. Description of the Background Art
The following U.S. patents and other publications may be relevant to the
present invention: U.S. Patent Nos. 4,453,536; 4,679,561;
4,765,331;'4,802,479;
5,190,517; 5,281,217; 5,293,869; 5,314,465; 5,314,466; 5,370,675; 5,423,811;
5,458,596; 5,496,312; 5,514,130; 5,536,267; 5,569,242; 5,588,960; 5,697,882;
5,697,909; and P.C.T. Published Application No. WO 97/20510.
SUMMARY OF THE INVENTION
The present invention provides improved devices, methods, and systems
for repeatably and reliably contracting fascia and other support tissues,
particularly for
the treatment of urinary incontinence. The techniques of the present invention
generally
enhance the support provided by the natural tissues of the pelvic floor.
Rather than
relying entirely on the surgeon's ability to observe, direct, and control the
selective
shrinking of these tissues, the present invention generally makes use of
tissue
contraction systems which are placed statically against the target tissue, and
which
direct sufficient energy into the tissue so as to inhibit incontinence or the
like.
In the preferred embodiment, a thin semi-rigid or rigid credit card shaped
device is inserted and urged flat against the endopelvic fascia. An array of
electrodes is
distributed across a treatment surface of the device, and the treatment
surface will often
be offset laterally from the urethra to avoid injury to the urinary sphincter
or other delicate
tissues. The treatment surface will often engage a relatively large area of
the endopelvic
fascia, and will be held in a static position against this tissue while the
electrodes are
energized under computer control. The electrodes can heat, stiffen andlor
shrink the
engaged endopelvic fascia with minimal collateral damage to the surrounding
fascia and
tissues, while the device structure and controller will together generally
avoid ablation of
the engaged endopelvic fascia.
Advantageously, sufficient shrinkage can be provided by the device in the
static position so that no additional heating/tissue contraction treatments
may be
required to the endopelvic fascia on the engaged side of the urethra. Hence,
the present
invention can take advantage of automated energy delivery circuits and/or
selectable
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contraction probes having treatment surfaces of a variety of selectable sizes
and shapes
so as to predictably contract the target tissue, rather than relying entirely
on a surgeon's
skill to contract the proper amount of tissue, for example, by manually
"painting" a small
electrode along the tissue surface, and may also reduce fouling along the
electrode/tissue interface.
In a first aspect, the present invention provides a method for use in a
therapy for inhibiting incontinence. The therapy effects a desired contraction
of a target
region within a collagenous endopelvic support tissue. The method comprises
engaging
a surface of a probe against the target region of the endopelvic support
tissue. Energy is
directed from an array of transmission elements disposed on the probe surface
to heat
the support tissue so that the heat alters the target region and the support
tissue inhibits
incontinence. The energy directing step is preferably performed without moving
the
probe.
The energy directing step will often comprise transmitting the energy
across a probe surfaceltissue interface having a length of at least 10 mm and
a width of
at least 5 mm. The energy will be sufficient to contract andlor stiffen the
endopelvic
support tissue with minimal damage to underlying tissue. In the exemplary
embodiment,
the energy directing step comprises applying bipolar electrical energy between
a plurality
of electrode pairs.
In another aspect, the present invention provides a method for use in a
therapy for incontinence. The incontinence therapy includes effecting a
desired
modification of an endopelvic fascia. The endopelvic fascia is composed of a
left portion
and a right portion. The method comprises accessing a first target region
along the left
or right portion of the endopelvic fascia. The first target region is offset
laterally from the
urethra. A probe surface is positioned against the first target region, and
energy is
directed from the positioned probe surface into the first target region so as
to effect the
desired modification of the left or right portion of the endopelvic fascia.
This energy is
directed without moving the positioned probe surface.
Generally, a second target region along the other portion of the
endopelvic fascia will also be accessed. The second region is offset laterally
from the
urethra, so that the urethra is disposed between, and separated from, the
first and
second target portions. Energy is directed from a probe surface into the
second region
so as to effect khe desired contraction of the other portion without moving
the probe
surface. These energy directing steps may optionally be performed
simultaneously, or
may be performed sequentially by moving the probe from one side to the other.
A
protective zone of the probe surface can be aligned with the urethra to ensure
that
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energy is not inadvertently transmitted from the treatment surface to this
delicate tissue
structure. Such alignment may be facilitated by introducing a catheter into
the urethra.
In another aspect, the invention provides a method for selectively
contracting a target tissue. The method comprises aligning a treatment surface
of a
probe with a first portion of the target tissue. The treatment surface has a
peripheral
portion and an interior portion. Energy is directed from the treatment surface
into the first
portion of target tissue so as to contract the first portion. Contraction of
the first portion
draws a second portion of the target tissue into alignment with the peripheral
portion of
the treatment surface. Energy can then be selectively directed from t~e
peripheral
portion of the treatment surface into the second portion of the target tissue.
Advantageously, this allows tissue which was brought into alignment with the
probe
during the beginning of the treatment to be heated and contracted as it is
drawn under
the electrodes without over-treatment of the previously contracted tissue.
In another aspect, the invention provides a device for effecting change in
a target region of a collagenous support tissue so as to provide a desired
change in a
structural support from the support tissue. The device comprises a probe
having a
treatment surface. At least one element is disposed along the treatment
surface for
transmitting energy from the treatment surface to the target region. Control
means are
coupled to the energy transmitting element for controlling the energy so that
the energy
effects the desired change without moving the probe.
In another aspect, the invention provides a device for effecting contraction
of a target fascial tissue. The target tissue has a fascial surface. The
device comprises
a probe body having a treatment surface. The treatment surface is oriented for
engaging
the fascial surface, and has a length of at least about 10 mm and a width of
at least
about 5 mm. The probe body is at least semi-rigid. An array of electrodes are
distributed over the target treatment surface for transmitting energy into the
engaged
target tissue without moving the probe, such that the energy contracts the
target tissue.
In another aspect, the invention provides a therapy kit. The therapy kit
comprises a probe and instructions for using the probe. The instructions
include
directing energy from the probe into a target region of an endopelvic support
tissue
without moving the probe. The heat alters the target region such that the
support tissue
inhibits incontinence.
In yet another aspect, the invention provides a device for contracting a
target tissue having a tissue surface. The device comprises a probe having a
treatment
surface oriented for engaging the tissue surface of the target tissue. An
electrode is
disposed on the treatment surface of the probe, and is engageable against the
target
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tissue surface so as to contract the engaged target tissue from an initial
size to a
contracted size. The electrode comprises a peripheral portion and an interior
portion.
The interior portion has an area corresponding to the contracted size of the
tissue. The
peripheral portion is energizeable independently from the interior portion.
This
advantageous structure allows the tissue immediately surrounding the
contracted tissue
to be heated and contracted without overtreating (and imposing unnecessary
trauma) on
the previously contracted tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a lateral cross-sectional view showing the urinary bladder and a
bladder support structure.
Fig. 2 is a cross-sectional view of a patient suffering from urinary stress
incontinence due to inelastic stretching of the endopelvic fascia.
Fig. 3 shows a known method for treating urinary incontinence by affixing
sutures around the bladder neck.
Fig. 4 illustrates improved bladder support provided by contracting the
endopelvic fascia according to the principles of the present invention.
Fig. 5 is a perspective view of a probe having a thin flat credit card shaped
body and a treatment surface with a two-dimensional array of bi-polar
electrode pairs.
Fig. 5A is a front view of the probe of Fig. 5.
Figs. 5B and C are side and front views, respectively, of a probe having
an electrode array supported by a shaft.
Figs. 5D-G illustrate the structure and electrical layout of the electrode
array for the probe of Figs. 5A and B.
Figs. 6A-C are schematic block diagram showings of a static tissue
contraction system having an electrode array with optional temperature
feedback
signals.
Figs. 7A-E schematically illustrate methods for accessing left and right
target regions of the endopelvic fascia.
Fig. 8 is a cross-sectional view showing a method for treating a left target
region of the endopelvic fascia.
Figs. 9A-D schematically illustrate a picture frame shaped tissue
contraction device having an independently energizeable peripheral portion so
as to treat
tissue surrounding an initially contracted region.
Figs. 10A and B illustrate an alternative probe having a two-dimensional
electrode array
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Figs. 11A and B illustrate a probe structure having a two-dimensional
array of posts for independently engaging, heating and contracting tissue, in
which the
posts may optionally include resistive heaters and temperature sensors.
Fig. 12 is a cross-sectional view of a probe structure having heat transfer
surfaces thermally coupled to diodes and to the target tissue so as to allow
the diodes to
act as both heaters and temperature sensors.
Fig. 12A is a drive/feedback block diagram for the probe of Fig. 12.
Fig. 13 illustrates an alternative probe structure in which a conduit directs
a heated fluid along a treatment surface of the probe.
Fig. 14 illustrates a still further alternative probe in which a plurality of
irrigation ports are disposed between a one-dimensional array of elongate
electrodes.
Fig. 15 illustrates a semi-rigid probe body which flexes to help ensure the
treatment surface of the probe is in contact with the target tissue.
Fig. 16 illustrates a probe having a cavity that receives the urethra to help
ensure that the treatment surface is separated from the urethra by a
protection zone.
Figs. 17A-C illustrate front and side views of a probe having a balloon
which urges the treatment surface of the probe against the target tissue.
Figs. 18A-C illustrate a minimally invasive probe having interspersed
heating and cooling areas to effect tissue contraction with minimal damage to
the target
tissue, and in which the probe includes a balloon that can be inserted to a
treatment site
in a narrow configuration and expanded at the treatment site to engage and
treat the full
target region without moving the probe.
Figs. 19A-C illustrate a probe having interspersed hot and cold posts.
Fig. 20 is a cross-sectional view showing a probe having a heating
element with a limited quantity of a reaction material such that the total
heat energy that
will be transmitted to the target tissue is limited.
Fig. 21 illustrates a tissue contracting kit including the probe of Fig. 5 and
instructions for its use.
3O DESCRIPTION OF THE SPECIFIC EMBODIMENTS
The present invention generally provides methods, devices, and systems which
repeatably contract tissue, particularly as a therapy for incontinence. The
techniques of
the invention will generally involve positioning a probe so that a surface of
the probe
engages a target tissue statically, that is, without relative movement between
the probe
and the engaged tissue surface during treatment. Energy will then be
transmitted from
the treatment surface of the probe into the target tissue so as to effect the
desired
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contraction. This allows the contraction to be controlled by the configuration
and/or
software of the system, rather than relying on a surgeon's experience to allow
him or her
to "paint" a small area electrode surface across a sufficient portion of the
target region at
a proper rate to effect contraction without imposing excessive injury on the
target tissue.
As these techniques will be effective for controllably and repeatably
contracting a wide
variety of fascia and other collagenated tissues throughout the body, they
will find
applications in a wide variety of therapies, including skin wrinkle shrinkage,
tightening
stretched tendons and ligaments in knees, ankles, and wrists, treatment of
droopy
eyelids, shrinking large earlobes, and the like. However, the most immediate
application
for the invention will be to enhance the patient's own natural support of the
bladder,
bladder neck region, and urethra so as to inhibit urinary incontinence.
The techniques of the present invention will often be used to contract
fascia, tendons, and other collagenous tissues, preferably without ablation of
these
collagenous tissues. As used herein, this means that collagenous tissues are
not
removed and their function (particularly their structural support function) is
not destroyed.
Histologically, some tissue necrosis may occur, and the structural strength of
the
contracted tissue may initially decrease after treatment. Nonetheless, the
treated tissues
will generally continue to provide at least some structural support, and their
structural
strength should increase during the healing process so that the healed,
contracted tissue
has at least almost the same structural strength as, and preferably greater
structural
strength (for example, stretching less under tension) than before treatment.
Collagenous
tissues may occasionally be referred to herein as collagenated tissues.
The pelvic support tissues which generally maintain the position of much
of the genitourinary tract, and particularly the position of urinary bladder
B, are illustrated
in Fig. 1. Of particular importance for the mefhod of the present invention,
endopelvic
fascia EF defines a hammock-tike structure which extends laterally between the
left and
right arcus tendinous fascia pelvis ATFP. These later structures extend
substantially
between the anterior and posterior portions of the pelvis, so that the
endopelvic fascia
EF largely defines the pelvic floor.
The fascial tissue of the pelvic floor may comprise tissues referred to
under different names by surgeons of different disciplines, and possibly even
by different
practitioners within a specialty. In fact, some surgeons may assign the
collagenous
support structure referred to herein as the endopelvic fascia one name when
viewed
from a superior approach, and a different name when viewed from an inferior
approach.
Some or all of this support structure may comprise two collagenous layers with
a thin
muscular layer therebetween, or may comprise a single collagenous layer. In
general
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terms, the therapy of the present invention may be directed toward any of the
collagenous portions of the support structures for the urethra, bladder neck,
and bladder.
Hence, the treated tissues may include and/or be referred to as endopelvic
fascia, arcus
tendinous fascia pelvis, urethropelvic ligaments, periurethral fascia, levator
fascia,
vesicopelvic fascia, transversalis fascia, and/or vesicle fascia, as well as
other
collagenous support structures.
In women with urinary stress incontinence due to bladder neck
hypermobility, the bladder has typically dropped between about 1.0 cm and 1.5
cm (or
more) below its nominal position. This condition is typically due to wakening
and/or
stretching of the pelvic support tissues, including the endopelvic fasda, the
arcus
tendinous fascia pelvis, and the surrounding ligaments and muscles, often as a
result of
bearing children.
When a woman with urinary stress incontinence sneezes, coughs, laughs,
or exercises, the abdominal pressure often increases momentarily. Such
pressure
pulses force the bladder to descend still farther, shortening or misaligning
the urethra UR
and momentarily opening the urinary sphincter.
As can be most clearly understood with reference to Figs. 2-4, the present
invention generally provides a therapy which effectively reduces the length of
the pelvic
support tissues and returns bladder B towards its nominal position.
Advantageously, the
bladder is still supported by the fascia, muscles, ligaments, and tendons of
the natural
pelvic support tissues.
Referring now to Fig. 2, bladder B can be seen to have dropped from its
nominal position (shown in phantom by outline 10). While endopelvic fascia EF
still
supports bladder B to maintain continence when the patient is at rest, a
momentary
pressure pulse P opens the bladder neck N resulting in a release of urine
through
urethra UR.
A known treatment for urinary stress incontinence relies on suture S to
hold bladder neck N closed so as to prevent inadvertent voiding, as seen in
Fig. 3.
Suture S may be attached to bone anchors affixed to the pubic bone, ligaments
higher in
the pelvic region, or the like. In any case, loose sutures provide
insufficient support of
bladder neck N and fail to overcome urinary stress incontinence. Over
tightening suture
S may make normal urination difficult and/or impossible.
As shown in Fig. 4, by reducing the effective length of the natural pelvic
support tissues, bladder B may be elevated from its lowered position (shown by
lowered
outline 12). Alternatively, contraction of selected tissues may reduce or
eliminate slack
in the support structures without raising the bladder, andlor may reduce the
elongation of
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the support structures to reduce dropping of the bladder when under stress. A
pressure
pulse P will then be resisted in part by endopelvic fascia EF which supports
the lower
portion of the bladder, helping maintain the bladder neck in a closed
configuration. .
Fine tuning of the support provided by the endopelvic fascia is possible
through selective modification of the anterior portion of the endopelvic
fascia. To close
the bladder neck and raise bladder B upward, for example, it may be possible
to effect a
greater total tissue contraction towards the front. Alternatively,
repositioning of bladder B
to a more forward position may be affected by selectively contracting the
dorsal portion
of the endopelvic fascia EF to a greater extent then the forward porti9n.
Hence, the
therapy of the present invention may be tailored to the particular weakening
exhibited by
a patient's pelvic support structures. Regardless, the portion of the
endopelvic fascia EF
adjacent the bladder neck and urethra UR can remain free of sutures or other
artificial
support structures which might directly compress the urethra.
Referring now to Fig. 5, a credit card shaped probe 20 includes a thin flat
probe body 22 having a treatment surface 24. A twa-dimensional array of
electrodes 26
is distributed across treatment surface 24, the electrodes here being arranged
in bipolar
pairs. Conductors 28, here in the form of a plurality of insulated wires
jacketed in a
single bundle, extend from probe body 22 for coupling an electrical energy
source to
electrodes 26.
As seen most clearly in Fig. 5A, treatment surface 24 of probe 20 has a
length 29 and a width 30 that are significantly greater than a thickness of
probe body 22.
Length 24 will typically be at least about 10 mm, while width 30 will
generally be at least
about 5 mm. Preferably, length 28 will be between about 10 and 50 mm, with
width 30
being between about 5 and 30 mm.
Probe body 22 will usually have a thickness of between about 1 and 15
mm. In many embodiments, the thickness of probe body 22 will be about 8 mm or
less,
typically being from about 8 mm to about 1 mm, and preferably being about 5 mm
or
less. The probe body will often be at least semi-rigid. In other words,
although probe
body 22 may flex, the probe body will generally have a stiffness greater than
that of
fascial tissue. This helps ensure that each of electrodes 26 can be
effectively coupled to
the fascial tissue surface by urging an interior portion of the probe body
against the
target tissue. Body 22 may flex slightly during such pressure so that both
surfaces
conform somewhat to each other. Body 22 may be substantially rigid so that the
fascial
surface conforms substantially entirely to the shape of probe 20. The probe
body may
comprise a polymer such as polycarbonate, ABS plastic, or the like.
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Where electrodes are used to heat the target tissue, the tissue
temperature can be controlled in a variety of ways so as to limit variability
in efficacy.
Feedback to a computer which controls power to electrodes 26 might directly
indicate
temperature, or the computer might instead control the treatment time. Signals
might be
provided to the computer indicating the electrical power being used, the
electrical energy
which has been input to the tissue, or the impedance of the tissue as measured
by the
current and voltage of the RF energy delivered to the probe. Additionally, the
spacing
between treated and non-treated regions may be set by the structure of the
probe and
array, and/or by selectively energizing the electrodes of the probe. Tf~is
further controls
the therapy to eliminate or reduce user variability.
Electrodes 26 may be substantially flush with tissue treatment surface 24,
or may alternatively protrude from the tissue treatment surface. When
protruding
electrodes are used, they will often present a rounded surface for engagement
against
the fascial tissue so as to minimize the concentration of electrical current
density (as
might otherwise occur at sharp corners). As is explained in more detail in
U.S. Patent
Application No. 08/910,370, filed August 13, 1997, the full disclosure of
which is
incorporated herein by reference, the depth of tissue treatment may be varied
when
using bi-polar electrodes by setting the spacing 32 between a pair of
electrodes 34,
and/or by setting a diameter or radius of curvature of electrodes 26 where
they engage
the tissue surface. In the exemplary embodiment, the electrodes have a radius
of
curvature of 0.012 inches, are formed of stainless steel, and are separated by
about six
times the radius of curvature {between their inner edges) to limit heating
depth to less
than about 3 mm. The spacing between electrode pairs should allow treatment of
a
relatively large amount of fascia without damage to the urethra. Spacing
between pairs
may also leave some untreated tissue interspersed between the treated regions,
which
will promote healing. The interspersed untreated areas of the target tissue
may
comprise fascia and/or other collagenous tissues, and the pairs may be
separated such
that at least a portion of the untreated tissue can remain at or below a
maximum safe
tissue temperature throughout treatment, optionally remaining below 60°
C, and in some
embodiments remaining below 45° C.
Using a bipolar credit card shaped configuration, a fascial tissue can be
safely heated to a contraction temperature by transmitting a current between a
pair of
electrodes having a radius of curvature at the tissue interface in a range
from about 0.05
to about 2.0 mm, ideally being about 0.3 mm, where the electrodes are
separated by a
distance in the range from about 1 to about 10 times the radius of curvature
of the
electrodes. This generally allows heating of the fascial tissue to a depth in
the range
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between about 0.5 and 10 mm from the engaged tissue surface, typically using
an
alternating current at a frequency at between about 100 kHz and 10 MHz with a
voltage
in a range of from about 10 to about 100 volts rms (ideally being about 60
volts rms) and
a current in a range from about 0.1 to about 10 rms amps. The driving energy
may be
applied using an intermittent duty cycle to effect the desired increase in
temperature.
Generally, the tissue will be heated to a safe contraction temperature in a
range from
about 70° C to about 140° C for a time in the range from about
0.5 to about 40 sees,
typically for a time from about 0.5 to about 10 sees.
An alternative probe structure 20' is illustrated in Figsy5B and C. In this
embodiment, probe body 22 is supported by a rigid shaft 23 extending from a
handle 25.
Shaft 23 may be bent to orient treatment surface 24 to engage the endopelvic
fascia.
Optionally, a flex joint 27 may be provided at the junction of shaft 23 and
probe body 22
to help ensure that the entire treatment surface 24 engages the fascial
surface when the
treatment surface is held in position manually from handle 25. Joint 27 may
comprise a
pliable or resilient structure andlor material adjacent the shaft/body
interface, such as an
elastomer, a polymer, a ball and socket arrangement, a pair of orthogonal
pivots, or the
tike. Shaft 23 may comprise a stainless steel hypotube containing the
conductors
coupled to electrodes 26, or any of a variety of alternative metal, polymer,
or composite
structures. The handle will often comprise a polymer such as polycarbonate,
ABS
plastic, or the like, and may optionally include controls for energizing the
electrodes.
The configuration of the electrode array is generally fixed by the probe
body structure. This often sets the tissue heating pattern (based on the
electrode size
and spacing between electrode pairs), as the probe body will be held at a
fixed position
against the tissue during tissue heating. This predetermined heating pattern
helps avoid
over-treatment of some tissues and under contraction of others, as can occur
when
manually painting a small treatment surface repeatedly across the target
tissue.
It has been demonstrated that the shape and layout of the electrodes can
provide preferential contraction of the target tissue along a desired
orientation. Using the
elongate electrodes 26 arranged in two series of three end-to-end pairs, and
heating
each pair of frst one series, and then the other series, sequentially
(starting with the
middle pair), the engaged tissue can be contracted to a significantly greater
extent in
width (across the electrode pairs) than in length (along the electrodes). In
fact, any
pattern of elongate heated tissue zones (such as between an elongate pair of
electrodes) may provide preferential contraction across the elongate heat
zones as
compared to along their length, particularly when such elongate heat zones are
alternated with elongate untreated zones (such as between the pairs). This can
be
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extremely useful when a surgeon wants to, for example, decrease a lateral
width of the
endopelvic fascia while minimizing the reduction in its anterior/posterior
length.
Probe body 22 will often be formed as a multilayer structure to facilitate
electrically coupling conductors 28 to electrodes 26. As shown in Fig. 5, for
monopolar
operation, only a single conductor need be electrically coupled to the
electrodes, while a
separate conductor can be coupled to a large return electrode placed on the
leg or back
of the patient. Bipolar operation will generally include at least two-
conductors, while
both monopolar and bipolar probes will often include larger numbers of
conductors to
selectively vary the electrical power across treatment surface 24.
An exemplary structure for probe body 22 of probe 20'' is illustrated in
Figs. 5D and E. Electrodes 26 are formed from wires of stainless steel,
copper, or the
like, but may alternatively comprise plates oriented perpendicularly to the
treatment
surface, the plates having rounded or radiused edges, with only the edges
exposed.
Electrodes 26 are coupled to the power supply with wires or other conductors
disposed
1 S between a main probe body 22a and a back insulating layer 22b. The
conductors extend
proximally through hypotube 23, which may also include a lumen for delivering
a
conduction enhancing liquid or gel, typically for delivery of about 1 cclmin
of saline
through one or more weep holes in treatment surface 24 adjacent or between the
pairs
of electrodes (as can be understood with reference to Fig. 14). Probe body 22
will
typically be rigid in this embodiment, often being formed of a polymer such as
ABS
plastic, polycarbonate, or the like, but may alternatively be semi-rigid
(typically
comprising silicone or nylon).
Probe 20 may optionally include a variety of mechanisms to actively
control contraction of the target tissue. Optionally, body 22 may include
multiplexing
circuitry which selectively directs electrical energy supplied through a
limited number of
conductors to the electrodes or electrode pairs. Such circuitry will
optionally vary the
electrical energy or duty cycle of the electrodes depending on temperatures
measured at
or near the electrodes. Alternatively, a uniform heating energy may be
directed from
treatment surface 24 based on one or more temperature measurements, based on
dosimetry, or the like. Circuitry for probe 20 may incorporate microprocessors
or the like.
Alternatively, signals may be transmitted from the probe to an external
processor for
control of the contraction energy.
Exemplary probe circuits are illustrated in Figs. 5F and G. The coupling
arrangement illustrated in Fig. 5F allows an M x N array of electrode pairs to
be
selectably energized using only M+N conductors. This arrangement takes
advantage of
the fact that current (and heating) will be concentrated along the path of
least electrical
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resistance, which will generally be between the two closest bipolar
electrodes. In this
case, rows of electrodes are coupled together and columns of electrodes are
coupled
together so that a particular electrode pair 1, 2, 3,...6 is selected by
driving a current
between the associated column and the associated row. For example, electrode
pair 3
is 'selected by driving bipolar current between the electrodes of column 1 and
the
electrodes of row 2. Current (and heating) between energized electrodes other
than pair
3 will not be sufficient to significantly contract tissue. in the exemplary
embodiment, the
electrode pairs are energized by heating each pair associated with a column
starting with
the middle pair (for example, pair 3, then pair 1, then pair 5), and then
moving on to the
next column (for example, pair 4, pair 2, and then pair 6}.
The probe circuit of Fig. 5G allows the electrode pairs to be selectively
energized, and further provides calibrated temperature information from
adjacent each
electrode pair (temperatures may be monitored selectively, for example, at the
active
electrode only). Temperature sensors 31 may comprise thermistors,
thermocouples, or
the like, and will be mounted to probe body 22 so as to engage the tissue
between a pair
of electrodes to limit the number of signal wires, temperature sensors 31 are
coupled to
a multiplexer MUX mounted in handle 25, or possibly in probe body 22. As such
temperature sensors provide temperature signals which are repeatable (for each
mounted sensor) though not necessarily predictable, the accuracy of the
temperature
feedback can be enhanced by storing calibration data for this probe, and
ideally for each
temperature sensor, in a non-volatile memory such as an EEPROM.
Static contraction systems including probe 20 are shown schematically in
Figs. 6A-C. In general, power from an electrical power source 33 is directed
to the
electrodes of probe 20' by a switching unit 35 under the direction of a
processor 37.
These functions may be combined in a variety of arrangements, such as by
including the
processor and the switching unit, some or all of the switching unit circuitry
with the probe,
or the like. Where temperature feedback is provided, such as in the system of
Fig. 6C,
the temperature may be controlled by selectively energizing and halting power
to the
probe (sometimes called a bang-bang feedback control) to maintain the desired
temperature or temperature profile, or the controller and/or switching unit
may selectively
vary the power level.
Advantageously, the total desired shrinkage of a discrete target region of
endopelvic fascia EF may be controlled without moving probe 20. Total
contraction of
the endopelvic fascia will depend on a number of factors. Generally, tissue
will contract
locally by up to 70% (areal shrinkage) when heated to contraction temperature
range.
Therefore, it is possible to select a probe 20 having a treatment surface 24
with a size
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and shape suitable for providing a total effective contraction of endopelvic
fascia EF so
as to provide the desired improvement in support of the pelvic floor. It may
therefore be
desirable to provide a series of differing probes for contracting tissues by
differing
amounts. For example, it may be possible to select a probe having a lateral
dimension
of 12 mm to decrease an effective lateral dimension of the right portion of
the endopelvic
fascia by 5 mm. A greater amount of contraction might be effected by selecting
an
alternate probe with a greater width. Selecting probes having differing
lengths, selecting
among alternative probes having treatment surfaces 24 which are wider at one
end than
the other, or selectively positioning the probe along the midline mighb allow
the surgeon
to tailor the enhanced support to lift the anterior or posterior portions~of
the bladder to a
greater or lesser degree, as desired.
Still further alternative contraction control mechanisms might be used.
Rather than selecting alternative probes, it may be possible to vary the
heating energy
among the electrodes. Where a lesser degree of contraction is desired, the
surgeon
1 S may heat the tissue to a lower temperature, and/or may selectively heat
only a portion of
the tissue which engages treatment surface 24 (for example, by energizing only
a
selected subset of electrodes 26). Electrical properties of the system can be
monitored
before, during, between, andlor after energizing the probe with tissue heating
current.
For example, as the controller selectively energizes the electrode pairs, the
system
impedance can be monitored to help ensure that sufficient electrode/tissue
coupling is
maintained for the desired treatment. In a simple feedback indication
arrangement, a
warning light may illuminate to inform the surgeon that coupling was (or is)
insufficient.
More sophisticated feedback systems may re-treat selected undertreated areas
by re-
energizing electrode pairs for which coupling was compromised. Generally,
these
feedback systems generate a feedback signal FS to indicate an effect of the
treatment
on the tissue, as schematically illustrated in Fig. 6A. Feedback signal FS may
simply
provide an indication to the surgeon, or may be processed by the controller to
modify the
treatment. Regardless, this controlled contraction can be provided without
moving probe
20.
Methods for accessing target regions of the endopelvic fascia are
illustrated in Figs. 7A-E. In general, endopelvic fascia EF can be viewed as
left and right
fascial portions separated at the patient's midline by urethra UR. Endopelvic
fascia EF is
supported by ligaments ATFP above a vaginal wall VW. It may be desirable to
selectively shrink endopelvic fascia EF along target regions 40 which extend
in an
anterior posterior direction along the left and right sides of the endopelvic
fascia. This
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should provide enhanced support of urethra UR, the bladder neck, and the
bladder with
little risk of heating, denervating or injuring the delicate urethral tissues.
To access target regions 40 with minimal trauma to the patient, a
weighted speculum 42 is inserted into the vagina to expose the anterior
vaginal wall VW.
Optionally, elongated laterally offset incisions 43 might be made in the
anterior vaginal
wall so that the vaginal mucosa could be manually dissected to reveal the
endopelvic
fascia EF. However, to minimize trauma and speed healing, a small incision 44
may be
made on either side of urethra UR, thereby allowing access for a minimally
invasive blunt
dissection device 46. Dissection device 46 includes a mechanical e~opansion
element in
the form of a balloon 48 at its distal end. Balloon 48 dissects the back side
of the vaginal
wall from the endopelvic fascia to create a minimally invasive treatment site
50 along
each of the discrete target regions 40, as seen in Fig. 7D. Regardless of the
specific
access technique, the exposed endopelvic fascia will preferably be irrigated
with saline
or the like to reduce fouling of the electrodes, and to enhance
electrode/tissue coupling
with a conductive film. The patient will preferably be positioned so that
excess irrigation
fluid drains from the tissue surface, and aspiration will often be provided to
clear any
drained fluids.
An alternative method for accessing the endopelvic fascia is illustrated in
Fig. 7E. This is sometimes referred to as the Raz technique, and generally
comprises
separating an arch-shaped mid-line flap F from the surrounding vaginal wall VW
to
access the underlying and adjacent endopelvic fascia as shown. This procedure
was
described in more detail by Shlomo Raz in Female Uroloay, 2nd. Ed. (1996) on
pages
395-397.
Referring now to Fig. 8, probe 20 is inserted through incisions 43 or 44 to
treatment site 50. Treatment surface 24 is urged against exposed surface 52 of
endopelvic fascia EF so that electrodes 26 are effectively coupled with the
endopelvic
fascia. Probe 20 may be biased against the endopelvic fascia manually by
pressing
against the wall of vaginal mucosa VM, by pressing directly against the probe
using a
finger inserted through incision 43 or 44, or using a shaft attached to the
probe that
extends proximally through the incision. Alternatively, as will be described
hereinbelow,
probe 20 may include a mechanical expansion mechanism for urging treatment
surface
24 against the endopelvic fascia EF.
Once the probe engages target region 40 of endopelvic fascia EF,
electrodes 26 are energized via conductors 28 (see Fig. 5). Electrodes 26
direct
electrical current through the endopelvic fascia so that the resistance of the
fascia
causes an increase in tissue temperature. The use of relatively large
electrode surfaces
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having a sufficiently large radius of curvature avoids excessive concentration
of electrical
current density near the tissue/electrode interface which might cause
charring, tissue
ablation, or excessive injury to the tissue.
As endopelvic fascia EF is heated by probe 20, the collagenated tissues
within the fascia contract, drawing the tissue inward along treatment surface
24.
Although probe 20 does not move during this contraction, it should be, noted
that at least
a portion of endopelvic fascia EF may slide along treatment surface 24, since
the tissue
contracts while the probe generally does not.
As can be understood with reference to Figs. 9A-D, the probes of the
present invention can effectively treat a larger region of the target tissue
than is initially
engaged by the treatment surface. Fig. 9A schematically illustrates a
treatment surface
24 having a peripheral "picture frame" portion 56 which can be energized
independently
of an interior portion 54. By energizing both portions 54 and 56, tissue 58
engaging
treatment surface 24 contracts inward as shown in Fig. 9B. Once this first
stage of
tissue has been contracted, however, additional heating of the contracted
tissue will
generally not provide contraction to the same degree, but may impose
additional injury.
Therefore, peripheral portion 56 can be energized independently of the
interior portion so
that the uncontracted tissue 60 that now engages treatment surface 24 can be
safety
contracted.
While interior portions 54 and peripheral portion 56 are illustrated as
contiguous treatment zones, it should be understood that they may actually
comprise
independently energizeable arrays of electrodes. Additionally, it should be
understood
that peripheral portion 56 need not completely surround interior portion 54,
particularly
where the probe includes some structure that affixes a portion of the probe
relative to the
engaged tissue.
A wide variety of alternative electrode array structures might be used. As
illustrated in Fig. 10A, electrodes 62 may optionally comprise monopolar or
bipolar
rounded buttons or flat disks defining a two-dimensional array. In some
embodiments, a
temperature sensor may be provided for each button. For bipolar heating,
radiofrequency current may be driven from one button electrode to another.
Alternatively, radiofrequency current may be driven from each button to a
large surface
area pad applied against the patient's back in a monopolar configuration.
When used in a bipolar mode, it may be desirable to drive radiofrequency
current between pairs of electrodes that are separated by at least one other
electrode.
This may allow heating to a more even depth, as heating energy will be
concentrated
near the engaged tissue surface adjacent each electrode, but will be
distributed to a
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greater depth midway between the electrodes of a bipolar pair. For example, it
is
possible to drive radiofrequency current from electrode 62a to electrode 62c,
from
electrode 62b to electrode 62d, from electrode 62e to electrode 62g, from
electrode 62f
to electrode 62h, and the like.
Advantageously, in an N X M electrode array, it is possible to
independently drive each of these electrode pairs using only N+M conductors
between
the driving power source and the electrodes, as described above regarding Fig.
5F.
A wide variety of alternative electrode and probe structures may be used.
For example, the button electrodes of Figs. 10A and B may be mounted on an
inflatable
balloon which could be rolled up into a narrow configuration for insertion to
the treatment
site. The balloon could then be inflated to allow engagement of the treatment
surface
against the target tissue.
A still further alternative probe structure is illustrated in Figs. 11A and B.
In this embodiment, a two-dimensional array of protrusions 64 each include a
resistive
heater 66 and a temperature sensor 68. As heat transfer between the probe and
the
tissue is by conduction of heat rather than by conduction of electrical
current, the ends of
protrusions 64 can safely include corners without concentrating heat. Hence,
the
protrusions can have heat transfer ends that are round, square, hexagonal, or
the like,
and the protrusions can be cylindrical, conical, or some other desired shape.
Alternatively, flush heat transfer surfaces may be formed with similar
structures.
Preferably, the protrusions 64 can be pressed against the tissue surface
and resistive heaters 66 can be energized while active temperature feedback is
provided
by temperature sensor 68. This feedback can be used to heat the protrusions to
the
desired treatment temperature for a predetermined time so as to effect the
desired tissue
contraction. Alternatively, the temperature sensors may measure the actual
temperature
of the tissue, rather than that of the protrusion.
Referring now to Fig. 12, a two-dimensional array of heat transfer
surfaces 70 might make use of thermally conductive materials that extend from
or are
flush with treatment surface 24. At least one electrical component 72 is
thermally
coupled to an associated heat transfer surface 70 so that the component varies
in
temperature with the temperature of the surface. The component will typically
have an
electrical characteristic which varies with temperature, the component
typically
comprising a transistor, thermistor, or silicon diode. Component 72 can be
coupled to
conductor 28 using a printed circuit board 74.
Electrical current is driven through component 72 so that the component
heats heat transfer surface 70. The tissue engaging heat transfer surface 24
is heated
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by passive conduction from heat transfer surfaces 70. Preferably, the heating
electrical
current is applied as intermittent pulses. Between heating pulses, a small
constant
current can be driven through a diode in a forward direction, and the voltage
across the
junction can be measured using printed circuit board 74. The forward voltage
across this
junction is often dependent on the temperature of the junction, typically
varying by about
2 mVl°C for a silicon diode. This forward voltage can be used to
measure the junction
temperature. The timing of the heating pulses and the structure of heat
transfer surface
70 can be set so that the diode junction will indicate the temperature of the
tissue against -
which the heat transfer surface is engaged, with the diode junction preferably
being at or
near an equilibrium temperature during a slow gradual heat cycle.
The temperature indication signal provided by the low-power, between
heating pulse can be used as a feedback control signal. The array ideally
comprises a
two-dimensional array, and feedback signals from multiple heat transfer
surfaces of the
array should allow very good control of the local tissue contraction
temperature
throughout the treatment surface/tissue interface. Such an array of
transistors or diodes
coupled to a power source via conductor 28 and printed circuit board 74
provides a very
inexpensive way to selectively control the temperature across treatment
surface 24.
Fig. 12A is an exemplary circuit including the probe of Fig. 12. A large
variable current 1, is sufficient to heat diodes 72 so as to treat the engaged
tissue,
preferably under proportional control. A small constant current Iz does not
significantly
heat the engaged tissue, but does allow measurement of the forward voltage
drop
across each diode. Applying a constant small current 12, the voltage drop
across a diode
72 thermally coupled (through a metal plate) to the tissue will be about 0.7 v
- 2 mV/°C
for a silicon diode so as to indicate the tissue temperature. Once again an
EEPROM or
other non-volatile memory may store calibration data for each diode, ideally
storing
calibration constants for at least two temperatures from calibration tests
conducted prior
to delivery and/or use of the probe.
As illustrated in Figs. 13 and 14, still further alternative heating
mechanisms might be used. In Fig. 13, a conduit 76 directs a relatively high
temperature
fluid along a serpentine path adjacent treatment surface 74, the heated fluid
typically
comprising steam or the like. In the embodiment of Fig. 14, a one dimensional
array of
elongate electrodes 80 is distributed across treatment surface 24, with
irrigation ports 82
being disposed between and/or around the electrodes.
When accessing the endopelvic fascia transvaginally, the midline need
not be dissected, as described above. This minimizes the possibility of
inadvertently
treating and/or injuring the urethra. Generally, treatment can be made
symmetric by
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statically positioning the probe against the target region on the left side of
the endopelvic
fascia, and statically positioning the same or a different probe on the right
side of the
endopelvic fascia without accessing the fascia adjacent the urethra.
Alternatively, it may
be possible to treat only one side and effectively inhibit incontinence,
particularly where
only one side of the endopelvic fascia has an excessive length.
Nonetheless,'it may be
desirable to access the endopelvic fascia across the midline, particularly
when treating
both the left and right target regions simultaneously with a single probe.
The use of a semi-rigid probe body 22 can be understood with reference
to Fig. 15. Probe 20 flexes when held against endopelvic fascia EF by a force
F to
ensure engagement between treatment surface 24 and the endopelvtc fascia
throughout
the desired interface region. Optionally, probe body 22 may be pre-curved to
facilitate
coupling between the treatment surface and the target tissue. For example, a
thin flat
probe body which is slightly convex might be held against the target tissue by
pressure
F2 at the edges of the treatment surface (rather than a central pressure F)
until the
device becomes substantially flat, thereby indicating to the surgeon that the
proper
amount of tissue engaging pressure is being applied.
Fig. 16 illustrdtes a structure and method for aligning probe body 22 along
the endopelvic fascia so that treatment region 40 is separated from the
urethra by a
protection zone 86. A catheter 88 is introduced into the urethra, which
facilitates
identification of the urethra along the endopelvic fascia. Optionally, cooled
water may be
circulated through the catheter to avoid any injury to the urethra during
treatment. It
should be understood that such a urethra) cooling system may be desirable for
many
embodiments of the present systems and methods.
To facilitate aligning treatment surface 24 with target region 40, urethra
UR is received in a cavity 88 of probe body 22. Cavity 88 is separated from
treatment
surface 24 by a desired protection zone 86. As a method for using this probe
will
generally involve dissecting the mucosa from the endopelvic fascia so as to
access the
fascia near urethra UR, the probe body may extend bilaterally on both sides of
the
urethra to simultaneously treat the left and right portions of the endopelvic
fascia, as is
indicated by the dashed outline 90. Such a bilateral system can avoid injury
to the
urethra) tissues by heating two (left and right) discrete treatment regions
separated by a
protection zone. Bilateral systems might evenly treat the two sides of the
endopelvic
fascia by sequentially energizing two separated arrays of electrodes in a
mirror-image
sequence, the two sides being treated simultaneously, sequentially, or in an
alternating
arrangement.
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Referring now to Figs. 17A-C, the static tissue contraction probes of the
present invention may optionally include an expansion mechanism such as
balloon 92 to
urge treatment surface 24 against the target tissue. The device might again be
inserted
through incisions into the anterior vaginal wall on either side of the
urethra. Electrodes
26 are again mounted on a probe body 22 which is at least semi-rigid, with a
resilient
balloon 92 molded to the back of the probe body. The balloon can be inflated
after the
probe is positioned to urge treatment surface 24 against the target tissue
with a
repeatable electrode/fascia interface pressure. Balloon 92 will preferably
comprise an
elastomer such as silicone or the like.
To improve coupling between the electrodes and the target tissue,
defibrillator gel or saline may be provided at the treatment surface/tissue
interface.
These enhanced coupling materials may be placed on the probe or tissue surface
prior
to engagement therebetween, or may alternatively be delivered through ports
adjacent
the electrodes.
Figs. 18A-C illustrate a still further alternative probe structure. In this
embodiment, an expandable probe 94 is inserted through a small incision while
the
probe is in a narrow configuration. Once the probe is positioned adjacent the
target
tissue, balloon 96 is inflated via an inflation lumen 98. The balloon expands
against an
opposing tissue so as to urge treatment surface 24 against the endopelvic
fascia.
Once inflated, fluid is passed through conduits adjacent the treatment
surface to thermally treat the endopelvic fascia. In this embodiment, a hot
fluid conduit
100 is arranged in a serpentine pattern which alternates with a cold fluid
conduit 102 so
that the treatment surface comprises interspersed zones of heating and
cooling. Heating
tissues to a safe contraction temperature between cooled zones will induce
contraction
with less injury to the tissue than would otherwise be imposed, as the regions
of heated
tissue are interspersed with, and protected by, the tissue cooling.
Still further alternative treatment mechanisms are illustrated in Figs. 19A-
C, and in Fig. 20. In the embodiment of Figs. 19, tissue heating and cooling
are
interspersed using a device which includes a heated plate 104 having a series
of heated
protrusions 106 in combination with a cooled plate 108 having interspersed
cooled
protrusions 110 and passages 112. Passages 112 receive heated protrusions 106,
while
a thermally insulating material 114 insulates the plates surrounding the
protrusions from
each other and the target tissue.
This device may optionally make use of active resistive heating of the
entire hot plate 104, in some cases with temperature feedback provided from a
single
temperature sensor. In such cases, hot plate 104 wilt preferably be thick
enough so that
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heat transfer through the plate from protrusion to protrusion is sufficient so
that the
temperature gradient from one protrusion to another is negligible, allowing
uniform
treatment across the treatment surface. In alternative embodiments,
protrusions 106
may not be actively heated while in contact with the target tissue. Instead,
hot plate 104
may be heated prior to contact with the tissue so that heat transfer to the
tissue is
provided by the heat capacity of hot plate 104, as predetermined from the
specific heat
of the hot plate material, the quantity of hot plate material, and the like.
In fact, the
device may be preheated in an oven or the like, so that no active heating of
the plate is
provided for. Instead, the plate has sufficient heat capacity to treat the
tissue if applied
to the tissue for a predetermined amount of time.
In some embodiments, protrusions 106 may include resistive heating
elements such as those described above regarding Figs. 11 A-12, optionally
using a
combination of resistive heating and the heat capacity of the
protrusions,andlor plate.
Likewise, cold plate 108 may include a chilled fluid conduit, thermoelectric
cooling
module, or the like for actively cooling the plate, andlor may make use of the
heat
capacity of the plate to passively cool the tissue through cooled protrusions
110.
Fig. 20 illustrates an energy transmission element which is self-limiting. In
this embodiment, a heat transfer surface 116 (typically defined by a metal
barrier) is
heated by boiling an aqueous gel 118. Gel 118 is boiled by a resistive heater
120, and
the steam is directed through a nozzle 122 in an insulating material 124. The
heated
steam heats the heat transfer surface 116. Once the gel has boiled away,
insulating
material 124 substantially blocks the heat from resistive heater 120 from
reaching the
heat transfer surface 116. Advantageously, this provides a maximum temperature
determined by the boiling point of the aqueous gel, without requiring a
temperature
sensor. Furthermore, the maximum amount of heat delivered to the tissue is
determined
by the initial mass of the aqueous gel provided.
Fig. 21 schematically illustrates a kit 130 including probe 20 and its
instructions for use 132. Probe 20 may be replaced by any of the probe
structure
described herein, while instructions for use 132 will generally recite the
steps for
performing one or more of the above methods. The instructions will often be
printed,
optionally being at least in-part, comprise a video tape, a CD-ROM or other
machine
readable code, a graphical representation, or the like showing the above
methods.
While the exemplary embodiments have been described in some detail,
by way of example and for clarity of understanding, a variety of
modifications, changes,
and adaptations will be obvious to those of skill in the art. Therefore, the
scope of the
present invention is limited solely by the appended claims.
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