U.S. patent application number 13/347267 was filed with the patent office on 2012-05-03 for medical instruments and techniques for treatment of gastro-esophageal reflux disease.
Invention is credited to JAMES A. BAKER, John H. Shadduck.
Application Number | 20120109268 13/347267 |
Document ID | / |
Family ID | 25443520 |
Filed Date | 2012-05-03 |
United States Patent
Application |
20120109268 |
Kind Code |
A1 |
BAKER; JAMES A. ; et
al. |
May 3, 2012 |
MEDICAL INSTRUMENTS AND TECHNIQUES FOR TREATMENT OF
GASTRO-ESOPHAGEAL REFLUX DISEASE
Abstract
Apparatus and methods for treating tissue at or near a sphincter
provide for transluminal introduction of an energy delivery device.
The device includes a tissue compression member to compress target
tissue at or near the sphincter. A radiofrequency energy source is
coupleable to the delivery device to deliver radiofrequency energy
to the target tissue. Energy is delivered to heat the tissue to a
desired temperature. The desired temperature is selected to induce
an injury-healing response or to inducing shrinkage of collagen
fibers in the target tissue to thereby reduce laxity in the target
tissue.
Inventors: |
BAKER; JAMES A.; (Palo Alto,
CA) ; Shadduck; John H.; (Tiburon, CA) |
Family ID: |
25443520 |
Appl. No.: |
13/347267 |
Filed: |
January 10, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11656062 |
Jan 22, 2007 |
8095222 |
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13347267 |
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|
10375505 |
Feb 27, 2003 |
7167758 |
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11656062 |
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|
09648345 |
Aug 25, 2000 |
6535768 |
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10375505 |
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|
09258006 |
Feb 25, 1999 |
6197022 |
|
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09648345 |
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08920291 |
Aug 28, 1997 |
5957920 |
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09258006 |
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Current U.S.
Class: |
607/101 |
Current CPC
Class: |
A61B 18/1485 20130101;
A61B 2018/00708 20130101; A61B 2018/00714 20130101; A61B 2018/00875
20130101; A61B 2018/126 20130101; A61B 18/1492 20130101; A61B
2018/00678 20130101; A61B 2018/00214 20130101; A61B 2018/00666
20130101; A61B 2018/00505 20130101; A61B 2018/00702 20130101; A61B
2018/00791 20130101; A61B 2018/00553 20130101; A61B 2018/00898
20130101 |
Class at
Publication: |
607/101 |
International
Class: |
A61N 5/00 20060101
A61N005/00 |
Claims
1. An apparatus to treat a target tissue volume at or near a
sphincter comprising a radiofrequency energy delivery device having
a working end sized and configured for transluminal introduction
into a patient and including a tissue compression member deployable
to provide compression of target tissue at or near a sphincter, and
a radiofrequency energy source coupleable to the delivery device to
deliver radiofrequency energy to the target tissue to reduce laxity
in the target tissue.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of application Ser. No.
11/656,062 filed 22 Jan. 2007, which is a divisional of application
Ser. No. 10/375,505, filed Feb. 27, 2003 (now U.S. Pat. No.
7,167,758), which is a divisional of application Ser. No.
09/648,345, filed Aug. 25, 2000 (now U.S. Pat. No. 6,535,768),
which is a continuation of application Ser. No. 09/258,006 filed
Feb. 25, 1999 (now U.S. Pat. No. 6,197,022), which is a
continuation of application Ser. No. 08/920,291, filed Aug. 28,
1997 (now U.S. Pat. No. 5,957,920). This application relates to the
invention disclosed in Provisional application Ser. No. 60/024,974
filed Aug. 30, 1996 and is also related to provisional Application
Ser. No. 60/022,790 filed Jul. 30, 1996, both of which by this
reference are incorporated herein.
FIELD OF THE INVENTION
[0002] This invention relates to unique therapeutic instruments and
techniques for delivering thermal energy to a target tissue volume
or site in an interior of a patient's body in a "non-invasive"
manner for medical purposes, such as selective cell damage, cell
necrosis, molecular contraction or tissue stimulation. An exemplary
embodiment of the invention is a catheterlike device with a working
portion that can be introduced in a patient's urethra in a
treatment for urinary incontinence. A treatment for
gastroesophageal reflux disease also may be fashioned to increase
the rigidity or the length of the lower esophageal sphincter (LES)
by laying down a fiber matrix around the LES. The device delivers
thermal energy to "subsurface" or extraluminal tissues at a precise
pre-selected "target" site, at the same time minimizing trauma to
the wall around the lumen as well as tissues outward from the
"target" site. The principal use of the exemplary embodiment is to
selectively damage cells around a patient's sphincter which
thereafter causes population of the extracellular compartment of
the injury site with a collage fiber matrix. The collagen matrix
serves as a means of altering cellular architecture and thus the
bio-mechanical characteristics of the sphincter. The instrument of
the invention also may be used to hydrothermally shrink such
collagen fiber matrices in a periodic treatment cycle to further
"model" target tissue flexibility to further alter the
bio-mechanics of the sphincter.
SUMMARY OF THE INVENTION
[0003] According to one aspect of the invention, an apparatus to
treat a target tissue volume at or near a sphincter comprises a
radiofrequency energy delivery device. The delivery device has a
working end sized and configured for transluminal introduction into
a patient and includes a tissue compression member deployable to
provide compression of target tissue at or near a sphincter. A
radiofrequency energy source is coupleable to the delivery device
to deliver radiofrequency energy to the target tissue to reduce
laxity in the target tissue. In one embodiment, the delivery device
does not penetrate a wall of a body lumen.
[0004] The tissue compression member may take various forms, such
as a laterally extending extendable element or an inflatable
structure. Compression of the target tissue modifies the
extracellular fluid content of the target tissue to alter the
tissue's resistance to electrical energy. Compression of target
tissue decreases the level of extracellular fluid content of the
tissue to increase the target tissue's resistance to radiofrequency
energy while contemporaneously increasing the extracellular fluid
level in the surrounding tissue volume.
[0005] Energy is delivered to heat the targeted tissue to a desired
temperature. The desired temperature may be selected to stimulate
an injury-healing response that populates the targeted tissue with
collagen fiber matrix in extracellular space.
[0006] Alternatively, the desired temperature may be selected to
induce shrinkage of collagen fibers in the target tissue, e.g., in
response to denaturing, cleaving or partially denaturing
intermolecular cross-link or hydrogen bonds.
[0007] Another aspect of the invention provides a method of
treating tissue at or near a sphincter. A thermal energy delivery
device having a tissue compression member is introduced through a
body lumen to a targeted tissue site at or near a sphincter. The
tissue compression member is deployed to provide compression of the
target tissue at or near a sphincter. Radiofrequency energy is
delivered to the targeted tissue to induce an injury-healing
response. In one embodiment, energy is also be delivered to induce
shrinkage of collagen fibers in the targeted tissue.
[0008] Other subjects and objects of this disclosure relate to
novel techniques and instruments for the controlled modeling or
remodeling of cellular architectures in the interior of a patient's
body to alter the structural support of tissue layers, the support
within anatomic structures such as organs or body conduits, or to
alter the biomechanical characteristics of tissue masses or volumes
in the interior of the body, including but not limited to soft
tissues, organs and lumened structures (e.g., esophagus, urethra),
such tissues hereafter referred to as a "target" tissue volume or
mass.
[0009] In the prior art, site-specific thermal treatment of
cellular tissues in the interior of a patient's body generally
require direct contact of the targeted cellular tissues with a
medical device such as an thermal electrode, usually by a surgical
procedure that exposes both the targeted cellular tissue and
intervening tissue to trauma. For example, various microwave,
radiofrequency and light energy (laser) devices have been developed
for intraluminal use to thermally treat intraluminal tissues as
well as extraluminal tissue volumes to destroy malignant, benign
and other types of cells and tissues in a wide variety of anatomic
sites. Tissues treated include isolated carcinoma masses, and more
specifically, organs such as the prostate. Such prior art devices
typically include a catheter or cannula which is used to carry a
radiofrequency electrode or microwave antenna through an anatomic
duct or conduit to the region of treatment to apply energy directly
through the conduit wall into the surrounding tissue in all
directions. Severe trauma often is sustained by the duct wall
during the thermal energy delivery to extraluminal target tissues.
Some prior art devices combine cooling systems to reduce trauma to
the conduit wall. Such cooling mechanisms complicate the device and
require that the device be sufficiently large to accommodate this
cooling system. Other prior art devices use catheters with
penetrating elements that are extendable through the duct wall to
access the target tissue mass, such as a device for treating benign
prostatic hyperplasia.
[0010] More in particular, the present invention discloses
"non-invasive" techniques and instruments that utilize thermal
energy to selectively damage or injure certain cells in a
site-specific volume in the interior of a body. By the term
non-invasive, it is meant that the working end of the device does
not penetrate the interior of the body through any incision in
tissue. The non-invasive working end of the device still may be
disposed in the interior of the body by passing through an orifice
into a lumen or duct in a body-however, the device will not
penetrate a wall of the orifice.
[0011] The non-invasive selective damage to cells in target tissues
induces a biological response to the injury. Such a biological
response includes cell reproduction or repopulation along with the
proliferation of a fiber matrix of collagen in the extracellular
space. Thus, the controlled modeling of the structural or
mechanical characteristics of targeted tissue volume is possible by
creation of such a collagen fiber matrix therein. Such selective
injury to particular cell volume is accomplished by modifying the
extracellular fluid content (ECF) so as to increase its resistance
(R) to RF energy when compared to the surrounding tissue volume,
thus causing site-specific thermal energy delivery to selectively
injure a certain cell population.
[0012] Various terms may be suitable for describing either elements
of the process of thermal modeling of tissue by altering the
bio-mechanical characteristics of the targeted tissue volume with
the creation of a collagen matrix in the extracellular space. Terms
such as inducing connective tissue formation, aggregating fibrous
tissue, inducing the formation of scar tissue, tissue massing or
tissue bulking, fibrosis, fibrogenesis, fibrillogenesis, etc. have
been used.
[0013] Various other terms have been used to describe the thermal
effects on collagen molecules or fibers in the interior of the body
and deal with dimensional chances--such as tissue shrinkage,
molecular (both intra- and intermolecular) shrinkage, cellular
(both intra- and extracellular) shrinkage or contraction,
contracture, etc. For clarity of presentation, this disclosure will
use the terms "modeling" to describe an object of a treatment.
Other various terms relating to the formation of a extracellular
"collage matrix" or "matrices" having "fiber" characteristics will
be used for the purpose of describing more specific objects of the
invention. When referring to reducing dimensional changes in a
tissue volume, whether at the cellular or intracellular level, the
terms "shrinkage" or "contraction" will be used. These terms are
thus inclusive of the aforementioned words, and all, other phrases
and similar terms that relate to biophysical phenomena of collagen
matrix formation and tissue modeling described in more detail
below. The above described objects or the invention are
accomplished by controlled manipulation of bio-physical actions or
phenomena relating to (i) induction of the injury healing response
within a tissue volume in the interior of a body to populate the
volume with a collagen fiber matrix of in the extracellular space.
The objects of the invention further include (ii) the selective
hydrothermal shrinkage of collagen fibers in the target tissue
volume of surrounding tissue volumes subsequent to, or during, the
injury healing response.
[0014] As background, the injury healing response in a human body
is complex and first involves an inflammatory response. A very mild
injury will produce only the inflammatory reaction. More extensive
tissue trauma--no matter whether mechanical, chemical or
thermal--will induce the injury healing response and cause the
release of intracellular compounds into the extracellular
compartment at the injury site. This disclosure relates principally
to induction of the injury healing process by thermal energy
delivery; the temperature required to induce the process ranging
from about 45 to 65.degree. C. depending on the target tissue and
the duration of exposure. Such a temperature herein is referred to
as T.sub.cd (temperature level that causes "cell damage" to induce
the injury healing response). It is important to note that the
temperature necessary to cause cell damage may be substantially
lower than the temperature (T.sub.sc) necessary to shrink collagen
fibers described below.
[0015] In order to selectively damage cells to induce the
population of the extracellular compartment with a collagen fiber
matrix, "control" of the injury to a particular tissue volume mass
is essential. In this disclosure, a thermal energy source is
provided to selectively induce the injury healing response, and
more particularly an RF source. (It should be appreciated that
other thermal energy devices are possible, for example a laser with
or without a diffuser mechanism, or shortwave, microwave or
ultrasound). In an RF energy delivery mechanism, a high frequency
alternating current (e.g., from 100,000 Hz to 500,000 Hz) is
adapted to flow from a series of parallel electrodes into tissue.
The alternating current causes ionic agitation and friction in the
target tissue mass as the ions follow the changes in direction of
the alternating current. Such ionic agitation or frictional heating
thus does not result from direct tissue contact with an electrode.
In the delivery of energy to a soft tissue mass, I=E/R where I is
the intensity of the current in amperes, E is the energy potential
measured in volts and R is the tissue resistance measured in ohms.
In such a soft tissue mass, "current density" or level of current
intensity is an important gauge of energy delivery which relates to
the impedance of the tissue mass (I.sub.tc is impedance of target
cells). The level of heat generated within the target tissue mass
thus is influenced by several factors, such as (I) RF current
intensity, (ii) RF current frequency, (iii) cellular impedance
(I.sub.tc) levels within the target cells, (v) heat dissipation
from the target tissue mass; duration of RF delivery, and (vi)
distance of the tissue mass from the electrodes. Thus, an object of
the present invention is the delivery of "controlled" thermal
energy to a target tissue volume by utilizing a computer-controlled
system to vary the duration of current intensity and frequency
based on sensor feedback mechanisms.
[0016] The novel techniques disclosed herein also delivery thermal
energy in (i) a site-specific manner to a target tissue volume, and
(ii) in a manner that does not injure surface tissue while at the
same time delivering sufficient energy to damage subsurface cells.
The novel techniques are adapted to manipulate (compress or
decompress) the target tissue volume to alter regional cell or
tissue impedance (I.sub.tc). More particularly, in soft tissues
which are the subject of this disclosure, there is a varying amount
of extracellular fluid (BCE) that has a measurable ECF level. By
altering the ECF level, and/or the ionic character of the fluid,
the thermal energy that is delivered to a target site will generate
differing levels of extracellular temperature resulting in altered
levels of cell damage (from different current density). For
example, mechanical compression of a target tissue volume will
lower the volume's ECF level in a subsurface site-specific region,
the tissue volume thus increasing in impedance (I.sub.tc) and
becoming more of a resistor. At the same time, the surface tissues
are less susceptible to ECF alteration by such mechanical
compression which allows the temperature in the subsurface target
volume to reach the T.sub.cd (cell damage temperature) without
ablation of the surface layer.
[0017] In the initial cellular phase of injury healing,
granulocytes and macrophages appear and remove dead cells and
debris. In the subsequent early stages of inflammation, the
inflammatory exudate contains fibrinogen which together with
enzymes released from blood and tissue cells, cause fibrin to be
formed and laid down in the area of the injury. The fibrin servos
as a hemostatic barrier and acts as a scaffold for repair of the
injury site. Thereafter, fibroblasts migrate and either utilize the
fibrin as scaffolding or for contact guidance thus further
developing a fiber-like scaffold in the injury area. The
fibroblasts not only migrate to the injury site but also
proliferate. During this fibroplastic phase of cellular level
repair, an extracellular repair matrix is laid down that is largely
comprised of collagen. Depending on the extent of the injury to
tissue, it is the fibroblasts that synthesize collagen within the
extracellular compartment as a connective tissue matrix including
collage (hereafter nascent collagen), typically commencing about 36
to 72 hours after the injury.
[0018] Thus, in the healing response in a human body, tissue repair
occurs principally by fibrous tissue proliferation rather organ
regeneration. Most compound tissues or organs (e.g., epithelium
which is a tissue) are repaired by such fibrous connective tissue
formation. Such connective tissue matrices are the single most
prevalent tissue in the body and give structural rigidity or
support to tissue masses or layers. The principal components of
such connective tissues are three fiber-like proteins-principally
collagen, along with reticulin, elastin and a ground substrate. The
bio-mechanical properties of fibrous connective tissue and the
repair matrix are related primarily to the fibrous proteins of
collagen and elastin. As much as 25% of total body protein is
native collagen. In repair matrix tissue, it is believed that
nascent collagen is well in excess of 50%.
[0019] A brief description of the unique properties of collagen is
required. Collagen (native) is an extracellular protein found in
connective tissues throughout the body and thus contributes to the
strength of the musculo-skeletal system as well as the structural
support of organs. Five types of collagen have been identified that
seem to be specific to certain tissues, each differing in the
sequencing of amino acids in the collagen molecule. Type I collagen
is most commonly found in skin, tendons, bones and other connective
tissues of the integument. Type III collagen is most common in
muscles and other more elastic tissues.
[0020] It has been previously recognized that collagen (or collagen
fibers as later defined herein) will shrink or contract when
elevated in temperature to the range about 22 to 30 degrees above
normal body temperature, herein referred to as T.sub.sc
(temperature to shrink collagen) (about 60.degree. to 70.degree.
C.).
[0021] Extracellular collagen consists of a continuous helical
molecule made up of three polypeptide coil chains. Each of the
three chains is approximate equal length with the molecule being
about 1.4 nanometers in diameter and 300 nm, in length along its
longitudinal axis in its helical domain (medial portion of the
molecule). The spatial arrangement of the three peptide chains is
unique to collagen with each chain existing as a right-handed
helical coil. The superstructure of the molecule is represented by
the three chains being twisted into a left-handed superhelix. The
helical structure of each collagen molecule is bonded together by
heat labile intermolecular cross-links (or hydrogen cross-links)
between the three peptide chains providing the molecule with unique
physical properties, including high tensile strength along with
moderate elasticity. Additionally, there exists at one heat stabile
or covalent cross-link between the individual coils. The heat
labile cross links may be broken by mild thermal effects thus
causing the helical structure of the molecule to be destroyed (or
denatured) with the peptide chains separating into individual
randomly coiled structures. Such thermal destruction of the
cross-links results in the shrinkage of the collagen molecule along
its longitudinal axis to approximately one-third of its original
dimension. The contraction of collagen fibers at from 60.degree. C.
to 70.degree. C. is alternatively referred to as denaturing,
cleaving or partially denaturing the intermolecular cross-links or
hydrogen bonds.
[0022] A plurality of col laden molecules (also called fibrils)
aggregate naturally to form collagen fibers that collectively make
up the fibrous repair matrix. The collagen fibrils polymerize into
chains in a head-to-tail arrangement generally with each adjacent
chain overlapping another by one forth the length of the helical
domain in a quarter stagger fashion. The chains overlap in three
dimensions and each collagen fiber reaches a natural maximum
diameter, it is believed because the entire fiber is twisted
resulting in an increased surface area such that succeeding layers
of collagen molecules cannot bond with contact points on underlying
layers in the quarter-stagger arrangement.
[0023] It is believed that there exist pre-denaturational changes
in collagen fibrils and fibers due to elevation of heat which
include (i) initial destabilization of the intramolecular
cross-links, (ii) destabilization of the intermolecular
cross-links, (ii) partial helix-to-coil transformations associated
with denaturation of some or both intramolecular and intermolecular
cross-links, and (iii) complete denaturation of some, but not all,
molecules making up a collagen fibrils. Such pre-denaturational
changes all result in partial contraction or shrinkage of collagen
fibers in a collagen-containing tissue volume. By the term "partial
denaturation" or "at least partial denaturation" as used herein
which are associated with a method of the invention, it is meant
that at least some (but probably not all) of the heat labile
crosslinks of the collagen molecules making up a collagen fiber are
destabilized or denatured thus causing substantial contraction of
collagen fibers in a tissue mass. It is believed that such at least
partial denaturation of the collagen fibers will result in
shrinkage of the collagen and "tightening" of a collagen-containing
tissue volume up to about 50 to 60 percent of its original
dimensions (or volume).
[0024] Thus, the present invention is directed to non-invasive
techniques and instruments for controlled thermal energy delivery
to a selected tissue volume in the interior of a body to: (i)
selectively injure certain cells in the target tissue volume to
induce the biological injury healing response to populate the
extracellular compartment with a fiber matrix thereby altering the
structural support or flexibility characteristics of the target
tissue volume; and optionally (ii) to cause the shrinkage of either
"native" collagen or "nascent" collagen in the tissue volume to
further alter bio-mechanical characteristics of the tissue
volume.
[0025] More in particular, the thermal energy delivery (TED) device
of the present invention has a catheter-like form with a proximal
control end and a distal working portion dimensioned for
transluminal introduction. The working portion has radiused
laterally-extending elements that are deployable to engage target
issues on either side of the patient's sphincter. RF electrodes are
carried on the working faces of the opposing laterally-extending
elements for delivering thermal energy to the target tissues. Thus,
the working portion of device is capable of site specific
compression of the target tissue to decrease the level of
extracellular fluid (ECF) of the tissue to increase its resistance
to RF energy. What is important is that the resistance is increased
only locally within the target tissue volume by lowering of the ECF
level while contemporaneously increasing the ECF level in the
surrounding tissue volume. Thus, the interior of the target tissue
may be thermally elevated to a T.sub.cd (temperature for cell
damage) while at the same time the wall surface around the urethra
should not be ablated due by the thermal energy delivery.
[0026] The therapeutic phase commences and is accomplished under
various monitoring mechanisms, including but not limited to (i)
direct visualization, (ii) measurement of tissue impedance of the
target tissue volume, and (iii) utilization of ultrasound imaging
before and during treatment. The physician actuates the
pre-programmed therapeutic cycle for a period of time necessary to
elevate the target tissue volume to (temperature of cellular
damage) which is from 45' to 65' depending on duration.
[0027] During the therapeutic cycle, the delivery of thermal energy
is conducted under full-process feedback control. The delivery of
thermal energy induces the injury healing response which populates
the volume with an extracellular collagen matrix which after a
period of from 3 days to two weeks increases pressure on the
sphincter. The physician may thereafter repeat the treatment to
further model, the cellular architecture around the sphincter.
[0028] In subsequent therapeutic treatment cycles, the delivery of
thermal energy may be elevated to at least partially denature
collagen fibers in the extracellular matrix without damage or
substantial modification of surrounding tissue masses at a range
between 60.degree. to 80.degree. C. The effect of collagen
shrinkage will further stiffen the treated tissue volume to further
increase extraluminal pressures on the sphincter.
[0029] In general, the present invention advantageously provides
technique and devices for creating preferential injury to a
cellular volume in a subsurface target tissue.
[0030] The present invention provides techniques and instruments
for altering the flexibility or bio-mechanical characteristics of
subsurface target tissues.
[0031] The present invention provides a novel non-invasive devices
and techniques for thermally inducing the injury healing process in
the interior of the body without penetration of a tissue wall with
an instrument.
[0032] The present invention provides an instrument and technique
for modifying extracellular fluid content (ECF) of a target tissue
volume to alter the tissue's resistance to electrical energy.
[0033] The present invention advantageously provides an electrode
array for elevating current density from an electromagnetic
(thermal) energy source in "surface" tissues to a lesser level
while simultaneously elevating current density in "subsurface"
tissues to a higher level.
[0034] The present invention advantageously provides a thermal
energy delivery device which gives the operator information about
the temperature and other conditions created in both the tissue
targeted for treatment and the surrounding tissue.
[0035] The present invention provides a device that is both
inexpensive and disposable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is an elevational view of a the present invention
with the working portion in an insertion configuration.
[0037] FIG. 2 is an elevational view of device of FIG. I with the
working portion in a deployed configuration.
[0038] FIG. 3 is an enlarged perspective view of components of the
working portion of the device of FIG. 1 de-mated from one
another.
[0039] FIGS. 4A-4C are enlarged elevational views of the components
of the working portion of FIG. 1 in various positions.
[0040] FIG. 5 is a transverse sectional view of the device of FIG.
1 taken along line 5-5 of FIG. 4A.
[0041] FIG. 6 is a block diagram of a control portion of the
invention that includes a computer controller and energy
source.
[0042] FIGS. 7A-7D are a sequence of sectional views of a patient's
bladder and urethra showing the manner in which the instrument of
FIG. 1 is illustratively utilized to perform a method of the
invention in thermally treating tissue around the patient's
sphincter; FIG. 7A being a sectional views of the initial to of
introducing the device into the urethra; FIG. 7B being a view of
actuating certain laterally-extending elements of the working
portion in the patient's bladder; FIG. 7C being a view of actuating
certain laterally-extending elements of the working portion in the
patient's urethra; FIG. 7D being a view of approximating the
laterally-extending elements to compress tissue therebetween to
alter extracellular fluid content therein to facilitate an
electrosurgical treatment.
[0043] FIG. 8 is an enlarged sectional view of the compression of
target tissue and the delivery thermal energy taken along line 8-8
of FIG. 7D.
[0044] FIG. 9 is another enlarged sectional view of the compression
of target tissues similar to FIGS. 7D and 9 showing optional
current vectors.
[0045] FIGS. 10A-10C are plan views of a working portion of a Type
"B" embodiment of thermal energy delivery device.
[0046] FIGS. 11A-11B are plan views of an alternative embodiment of
the working portion of the Type "B" embodiment of FIG. 10A.
[0047] FIGS. 12A-12B are perspective and sectional views of a
working portion of a Type "C" embodiment of thermal energy delivery
device.
DETAILED DESCRIPTION OF THE INVENTION
I. Type "A" Embodiment of Thermal Energy Delivery (TED) Device
[0048] Referring to FIG. 1, a Type "A" embodiment of the present
invention is shown that is adapted for transluminal introduction to
treat specific target tissue regions around a patient's sphincter.
As shown in FIG. 1, thermal energy delivery (TED) system 5
comprises elongate flexible outer catheter sleeve 10 dimensioned
for transluminal passage with proximal end 11 and distal and 12 and
extending along axis 15. First distal handle portion 16 is coupled
to proximal end 11 of the outer sleeve. Catheter 10 has axial lumen
18 extending therethrough for accommodating the reciprocation of
co-axial inner sleeve 20 with working portion 25 coupled to both
inner and outer sleeves as described below. Second proximal handle
portion 26 is coupled to proximal end 21 of the inner sleeve 20.
Inner sleeve 20 with proximal end 21 and distal end 22 has
(optional) lumen 28 therein dimensioned to slidably receive a
fiberscope or so that system 5 may be introduced over a guide
catheter or scope (not shown).
[0049] Referring to FIGS. 3 and 4A, working portion 25 of system 5
comprises two cooperating tissue-engaging or tissue-compression
members 30 and 32 of any suitable material and is described in this
embodiment as made of a flexible plastic material. FIG. 3 shows
tissue-compression members 30 and 32 de-mated from one another and
de-mated from outer and inner catheter sleeves, 10 and 20. Proximal
member 30 is coupled to distal end 12 of outer sleeve 10. Distal
tissue-compression member 32 is coupled to distal end 22 of inner
sleeve 10. Tissue-compression member 30 has proximal end 40a and
distal end 40b and tissue-compression member 32 has proximal end
42a and distal end 42b. FIG. 3 also shows a plurality of
cooperating longitudinal keys 43a (collectively) in members 30 and
32 maintain angular registration between the tissue compression
members and allows for their axial reciprocation relative to one
another as described below.
[0050] Referring now to FIGS. 4A-4C, it can be seen that working
portion 25 is movable between a (first) insertion configuration
(FIG. 4A) and a (second) deployed configuration (FIG. 4B). In the
insertion configuration of FIG. 4A, each tissue-compression member
30 and 32 has laterally-extending elements in a (first) repose
position. In the deployed configuration of FIG. 4B, the
tissue-compression members 30 and 32 have laterally-extending
elements in a (second) articulated position. For example, member 30
has three laterally-extending elements or arm portions 45a-45c that
flex outwardly away from axis 15 of working portion 25. Each arm is
shown with living-type hinges wherein the entire member 30 is of a
resilient plastic. In general, proximal sliding movement of inner
sleeve 20 within bore 18 of outer sleeve 10 by means of moving
handle portion 26 in the proximal direction relative to handle 16
(FIGS. 1-2) causes proximal end 40a and distal end 40b of member 30
to be compressed axially toward one another resulting in arms
45a-45c flexing at living hinge points 46, 47 and 48
(collectively). Tissue-compression member 32 has three cooperating
arm portions 47a-47c that flex outwardly (similar to counterpart
member 30) at equivalent hinge points (not numbered). It should be
appreciated that the number of arms 45a-45c and 47a-47c may be from
one to four or more and for convenience are shown as numbering
three. FIGS. 3 and 4B show that distal end 22 of inner sleeve 20 is
coupled to shaft portion 50 and shaft 50 is fixed to distal end 42b
of member 32 thus allowing proximal end 42a (and bore portion 52
therein) of member 32 to slide over shaft 50.
[0051] FIG. 4B, shows that each laterally-extending elements or
arms 45a-45c of member 30 have radiused working faces 55
(collectively) that are somewhat rounded for engaging tissue such
that the tissue will not be penetrated. Similarly, arms 47a-47c of
member 32 have radiused working faces 56 (collectively).
[0052] Means are thus provided for altering the extracellular fluid
(ECF) content of tissue engaged by the laterally-extending elements
of working end 25 by tissue compression. As can be seen in FIGS.
4A-4B, arms 45a-45c and 47a-47c define gap 58 therebetween for
engaging target tissue and thereafter compressing the targeted
tissue sites. Additional axial reciprocating means are provided for
reducing the axial dimension of gap 58 after the arms are deployed
as shown in FIG. 4B. By comparing FIGS. 48 and 4C, it can be seen
that gap 58 is capable of moving from initial dimension A to
reduced dimension A' when inner sleeve 20 is moved axially relative
to outer sleeve 10 and overcomes the spring constant of helically
wound extension spring 59 that is disposed between opposing annular
faces (60a and 60b) of members 30 and 32, respectively (see FIG.
3). The spring constant of spring 59 is stronger than the
collective spring constants of the living hinges (e.g., 47-49) of
the arm elements described above. Thus, initial proximal axial
movement of inner sleeve 20 relative to outer sleeve 10 causes arms
45a-45c and 47a-47 to deploy (FIG. 4B). Additional proximal axial
movement of inner sleeve 20 relative to outer sleeve 10 causes
working races 55 and 56 of the arms to move closer axially (FIG.
4C).
[0053] It should be appreciated that a variety of spring loading
mechanisms may be used to actuate the arm elements in a particular
sequence. Preferably, the first proximal axial movement of inner
sleeve 20 relative to outer sleeve 10 will causes arms 47a-47c of
member 32 to deploy. The second or next proximal axial movement of
inner sleeve 20 relative to outer sleeve 10 will cause arms 45a-45c
of member 30 to deploy. In other words, two steps may be required
to move working end 25 to the configuration of FIG. 4B from the
configuration of FIG. 4A. Finally, the next or third proximal axial
movement of inner sleeve 20 relative to outer sleeve 10 will cause
gap 58 to be reduced from A to A' (see FIG. 4C). The control end
(handles 16 and 26) of the device preferably may be locked (not
shown) by any suitable means to maintain members 30 and 32 in the
articulated position. Further, the control end may comprise any
suitable mechanism for actuating the working end, e.g., a lever
arm, trigger, etc., and is shown as cooperating slidable handles 16
and 26 for convenience only.
[0054] Thermal energy delivery means are provided for thermally
treating target tissue engaged or compressed between working faces
55 and 56. Conductive electrodes or electrode arrays 70 and 72
(collectively) for delivering RF energy are shown carried in
respective working faces 55 and 56. Each electrode preferably is
individually controlled as described further below. FIG. 5 shows
that the walls of outer sleeve 10 and inner sleeve 20 have embedded
therein individual current-carrying wires 75a and 75b that supply
RF energy to each conductive electrode. Both groups of the
electrodes 70 and 72 are shown in FIGS. 4A-4C as being bipolar but
the electrodes may be operated in a mono-polar fashion with a
groundplate (not shown). Electrode material may include gold,
nickel titanium, platinum, stainless steel, aluminum and copper.
Referring to FIGS. 1-2, electrical cables 77 (collectively) are
connected to an RF energy source through a controller described
below which is adapted to deliver energy to electrodes 70 and
72.
[0055] Referring back to FIGS. 3 and 4A-4C, it can be seen that a
sensor array of individual sensors 80 (collectively) is provided in
a spaced relationship around working end 25 and arms 45a-45c and
47a-47c. The sensor array typically will include temperature
sensors, thermistors (temperature sensors that have resistances
that vary with the temperature level) and/or impedance sensing
elements that measure tissue impedance in various conventional
manners, although impedance measurement may obtained through
electrodes 70 and 72 without resort to dedicated electrodes and
circuits for impedance measuring purposes.
[0056] The electromagnetic energy delivery source 88, for example,
may be assumed to be an RF generator delivering energy to electrode
70 and 72. A multiplexer 90 is depleted in FIG. 6 which is
operatively connected to each electrode for measuring current,
voltage and temperature at thermal sensors 80 (collectively) spaced
around working end 25 or individually associated with each
electrode.
[0057] Multiplexer 90 is driven by a controller 100 which typically
is a digital computer with appropriate software. The controller
typically would include a CPU coupled to the multiplexer through a
bus. On the controller system, there may be a keyboard, disk drive
or other non-volatile memory system, displays as are well known in
the art for operating the system. Such an operator interface may
include various types of imaging systems for observing the
treatment such as thermal or infrared sensed displays, ultrasonic
imaging displays or impedance monitoring displays.
[0058] For such an operator interface, current supplied to
individual electrodes along with voltage may be used to calculate
impedance. Thermal sensors 80 carried in a position proximate to
electrodes 70 and 72 together with thermal sensors 102 positioned
within RF generator are adapted to measure energy delivery (current
and voltage) to each electrode at a treatment site during a
treatment cycle. The output measured by thermal sensors 80 and 102
are fed to controller 100 to control the delivery of power to each
electrode site. The controller 100 thus can be programmed to
control temperature and power such that a certain particular
temperature is never exceeded at the treatment site. The operator
further can set the desired temperature which can be maintained.
The controller has a timing feature further providing the operator
with the capability of maintaining a particular temperature at an
electrode site for a particular length of time. A power delivery
profile may be incorporated into controller 100 as well as a
pre-set for delivering a particular amount of energy. A feedback
system or feedback circuitry can be operatively connected to
impedance measuring system, the temperature sensors and other
indicators at the controller 100 or within the power source 88.
[0059] The controller software and circuitry, together with the
feedback circuitry, thus is capable of full process monitoring and
control of following process variables: (i) power delivery; (ii)
parameters of selected particular treatment cycle, (iii) mono-polar
or bi-polar energy delivery; and (iv) flow rate of coolant to
insulator wall portion of the introducer sheath if cooling is
provided. Further, the controller can determine when the treatment
is completed based on time, temperature or impedance or any
combination thereof. The above-listed process variables can be
controlled and varied in response to tissue temperatures measured
at multiple sites on tissue surfaces in contact with the device as
well as by impedance to current flow at measured at each electrode
which indicates the current carrying capability of the tissue
during the treatment process. Additionally, controller 100 can
provide multiplexing, can monitor circuit continuity for each
electrode and determine which electrode is delivering energy.
[0060] FIG. 6 shows a block diagram of a particular embodiment of
control circuitry. Note that thermal sensors can be thermistors
which provide differing resistance levels depending on temperature.
Amplifier 105 can be a conventional analog differential amplifier
for use with thermistors and transducers. The output of amplifier
105 is sequentially connected by analog multiplexer 90 to the input
of analog digital converter 110. The output of amplifier 105 is a
particular voltage that represents the respective sensed
temperatures. The digitized amplifier output voltages are supplied
to microprocessor 115. Microprocessor 115 thereafter calculates the
temperature and/or impedance of the tissue site in question.
Microprocessor 115 sequentially receives and stores digital data
representing impedance and temperature values. Each digital value
received by microprocessor corresponds to a different temperature
or impedance at a particular site.
[0061] The temperature and impedance values may be displayed on
operator interface as numerical values. The temperature and
impedance values also are compared by microprocessor 115 with
pre-programmed temperature, and impedance limits. When the measured
temperature value or impedance value at a particular site exceeds a
pre-determined limit, a warning or other indication is given on
operator interface and delivery of electromagnetic to a particular
electrode site or area can be decreased or multiplexed to another
electrode. A control signal from the microprocessor may reduce the
power level at the generator or power source, or de-energize the
power delivery to any particular electrode site. Controller
receives and stores digital values which represent temperatures and
impedance sent from the electrode and sensor sites. Calculated wall
surface temperatures within the urethra and the bladder may be
forwarded by controller 100 to the display and compared to a
predetermined limit to activate a warning indicator on the
display.
II. Method of Use of Type "A" Embodiment
[0062] Operation and use of the catheter shown in FIG. 1 in
performing a method of the present invention can be described
briefly as follows. Assume that the physician wishes to (i)
initially thermally treat target tissues around the patient's
bladder sphincter to alter the cellular architecture therein; and
optionally (ii) to subsequently thermally treat the target tissues
to contract the extracellular collagen matrix induced therein by
the initial thermal treatment.
[0063] FIG. 7A is a schematic cross-sectional drawing of the lower
female anatomy during use of the instrument and method of the
invention. The urethra 102 extends from the bladder 104 within fat
pad 106. Urinary incontinence is a condition characterized by a
malfunctioning sphincter 108 often caused by movement or slippage
of the bladder relative to pubic bone 110 within pad 106 and other
regional anatomic structures. As shown in FIG. 7A, in the method of
this invention, the catheter system 5 is passed upwardly through
the urethra 102 into the bladder 104 in the insertion configuration
(see FIG. 1). The position of working portion 25 is precisely
controlled using an ultrasound image, for example, obtained from
signals received from the conventional ultrasound transducer 125
inserted into vagina 130 adjacent to the bladder or with an
ultrasound transducer positioned outside the body (not shown). The
catheter system alternatively may be introduced over a fiberscope
previously inserted into the patient's urethra (not shown).
[0064] With the distal or terminal portion of working end 25 in the
bladder, the surgeon then moves handle portion 26 (FIG. 1) and
inner sleeve 20 proximally a first distance relative to outer
sleeve 10 and handle 16. As can be seen in FIG. 7B, such actuation
moves arm elements 47a-47c laterally away from or outward relative
to axis 15 to a first deployed position of working portion 25 thus
pressing working faces 56 (and electrodes 72) of the arms against
walls 132 of bladder 104.
[0065] Thereafter, the physician may angularly rotate the entire
catheter about its axis td orient one or more of the arm elements
toward tissues to be treated. The physician then moves handle
portion 26 (FIG. 1) and inner sleeve 20 proximally a second
distance relative to outer sleeve 10. As can be seen in FIG. 7C,
such further actuation moves arm elements 45a-45c to a second
deployed position being within the urethra 102 such that working
faces 55 of the these arms along with electrodes 70 are laterally
extended somewhat deep into the target tissues indicated at S. The
curvature and radiusing of working faces 50 insure that the arms do
not penetrate the walls 135 of the urethra. Finally, as shown in
FIG. 7G, the physician moves handle portion 26 and inner sleeve 20
proximally a third distance relative to outer sleeve 10 thereby
moving arm elements 45a-45c and 47a-47c (a third deployed position)
closer together to compress target tissue S therebetween (see FIG.
4C).
[0066] Referring to FIG. 8, the compression of target tissue S
between working faces 55 and 56 reduces the extracellular fluid
(ECF) content in tissue S thus increasing tissue S's resistance to
RF current. Thus, delivery of RF current through either electrodes
70 or 72 will, allow tissue S to be elevated to T.sub.cd
(temperature or cell damage) to induce the injury healing response
while surface layer L remains at a lower temperature such that the
surface layers will not be ablated, principally due to the fact
that surface layer L has a lower resistance (R) due to its higher
ECF level as well, as the fact that evaporative and convective
forces further reduce the temperature of surface layer L indicated
by arrows 138.
[0067] Still referring to FIG. 8, it further should be appreciated
that reduction of ECF level in target tissue S tends to increase
the ECF level in tissues W just outward or away from the most
compressed target tissue S. The non-compressed tissue W thus will
have a lesser resistance to RF current (due to increased ECF
content) and readily conducts the RF energy to target tissue S.
Thus, a temperature gradient will exist where the center of the
region of target tissue S will be elevated to the highest
temperature (a higher current density) than region W. Surface layer
L will have the lowest temperature due to increased ECF levels as
was tissue W as well as the evaporative/convective effects
affecting layer L mentioned above in other words, the compression
of target tissue caused it to act as a "fuse" or "fuse point"
surrounded by more conductive tissue volumes or layers. The center
point 140 of target tissue S is thus a focus of the heating which
is similar to a fuse.
[0068] Electrodes 70 and 72 on the arm elements are energized from
RF energy source 88 by actuation of a switch in the control end
(handle 16 or 26) of the catheter system 5 or from a foot pedal or
other suitable means. Preferably, the time and/or power levels are
preset by the controller 100. The RF energy from energy source 88
is delivered to the target tissue S for a pre-selected time.
Impedance also is monitored, and when or if it exceeds a preset
value, the energy source can be reduced or terminated automatically
by controller 100. The temperature of surfaces of working portion
25 adjacent the urethral wall 135 and adjacent to the bladder wall
122 are also monitored using temperature sensors attached to these
components to precisely control the treatment parameters and
prevent excessive heating of surface tissue layers L.
[0069] After target tissue S has sustained cell damage at the
desired level, the physician may collapse the arms 45a-45c and
47a-47c back onto working portion and either rotate the catheter
slightly and repeat the treatment or remove the device from the
patient's body.
[0070] It should be appreciated that arm elements, although shown
as angularly symmetric, may be asymmetric thus delivering energy to
a target sites in a pre-determined asymmetric pattern.
[0071] One or more temperature sensors 80, which can be
conventional thermistors, thermocouples or even optical fibers
communicating with external sensors, are positioned along the
catheter or arm elements to provide a temperature profile of the
urethra adjacent to and preferably on both sides the electrodes 70
and 72. This temperature profile can be used by the operator to
prevent the temperature of the urethral wall or bladder wall from
reaching level which would cause surface ablation. The RF energy
thus exposes the target tissue S to controlled heating to T.sub.cd
(temperature of cell damage) of approximately 45.degree. C. to
65.degree. C. Preferably, the temperature range is from 45.degree.
C. to 55.degree. C. Still more preferably, the temperature range is
from 45.degree. C. to 50.degree. C.
[0072] The RF current typically is delivered between opposing
electrodes 70 and 72 in a bi-polar manner as shown by broken arrows
in FIG. 8. In certain selected instances, more directed cell damage
can be obtained by alternating the bi-polar flow of current in
various vectors indicated by broken arrows in FIG. 9. In other
instances, one or more of the electrodes may act as a mono-polar
electrode and a delivery energy to a grounding plate (not shown).
The RF treatment is continued until the cells in the target tissue
S have been damaged as indicated by dotted lines in FIGS. 8 and 9.
The cell damage induces the body's injury healing response which
thereafter populates the extracellular compartment with a collagen
fiber matrix having the effect of bulking tissue and reducing the
flexibility of tissues as described above. Such tissue bulking or
tissue stiffening causes extraluminal pressures around the
sphincter and helps restore the sphincter's ability to pinch off
urine flow. A similar procedure may be performed to enhance
extraluminal pressures around the sphincter of the esophagus.
[0073] This procedure is unique in that it is the first
transluminal procedure which selectively provides the ability to
limit the treatment to the extraluminal target tissues and spares
the normal tissue of the organ wall from excessive temperatures.
This procedure also minimizes the trauma sustained by tissues
surrounding urethra 102, especially when compared to previously
known procedures. The procedure may be carried out under local
anesthesia only, depending upon the rate of energy delivery and
degree of pain sensation experienced by the patient. When local
anesthetic is adequate, the procedure can be performed in the
physician's office. Such a procedure still could be provided on an
outpatient basis and would require a short term (1-3 hour)
observation. If the procedure and patient require greater pain
control, then spinal anesthesia or a general anesthesia may be used
which would mandate the procedure be carried out in the operating
room.
[0074] Following a therapeutic cycle, the patient may return to
normal activities with careful monitoring of the sphincter
function. Thereafter, perhaps on a bi-weekly or monthly basis, the
identical treatment cycle may be repeated in a one or more
subsequent cycles until the desired reduction in tissue flexibility
and pressure on the sphincter is achieved. It is believed that such
periodic treatments (e.g., from 1 to 3 treatments over a period of
a few weeks) may be best suited to stiffen target tissue S and to
correct sphincter function.
[0075] In the subsequent treatment cycles, the temperature profile
may be programmed to attain the slightly higher level Tsc necessary
to shrink collagen fibers in the extracellular collagen matrix
induced by the original treatment. The controller 100 and
preprogrammed therapy cycle still will allow the temperature of the
organ wall to be low enough so as to prevent surface ablation by
making the energy delivery intermittent. The RF energy thus exposes
the target tissue S to controlled heating to Tsc (temperature
necessary to shrink collagen) of approximately 50.degree. C. to
80.degree. C. More preferably, the RF energy exposes tissue S to
controlled heating of approximately 60.degree. C. to 70.degree. C.
Still more preferably, the RF enemy exposes tissue S to controlled
heating of approximately 65.degree. C. to 70.degree. C.
III. Type "B" Embodiment of Thermal Energy Deliver, (TED)
Device
[0076] Referring to FIGS. 10A-10C, a Type "B" embodiment of the
present invention is shown that is adapted for transluminal
introduction and is similar in most respects to the first-described
embodiment Like reference numerals refer to like components of the
Type "A" and Type "B" devices.
[0077] The Type "B" device differs principally in that the distal
tissue compression member 32 that is coupled to the distal end 22
of inner sleeve 20 carries an inflatable structure 150 rather than
laterally extendable elements. The inflatable structure 150
communicates with any conventional pressure source (e.g., a
syringe) through lumen 25 in the wall of inner sleeve 20 (FIG. 10).
Preferably, inflatable structure 150 is of a non-compliant material
such as PET but also may be an elastomer such as latex or
silicone.
[0078] In use, the Type "B" embodiment is used in a fashion similar
to that described above. First, the catheter is introduced into the
organ and then inflatable structure 150 is expanded. Thereafter,
the proximal arms 45a-45c are extended laterally to compress tissue
between the arms 45a-45c and inflatable structure 150. RF energy
may be delivered is a monopolar fashion. Alternatively, the surface
of the inflatable structure 150 may have a plurality of opposing
electrodes 152 and the RF energy may be delivered in a bi-polar
fashion as described previously. Another alternative embodiment of
inflatable structure 150 could include a metallic mesh 155 as a
return electrode covering a substantial portion of the surface of
the inflatable structure facing electrodes 60 (see FIGS.
11A-11B).
IV. Type "C" Embodiment of Thermal Energy Delivery (TED) Device
[0079] Referring to FIGS. 12A-12B, a Type "C" embodiment of the
present invention is shown that is very similar to the
first-described Type "A" embodiment. Like reference numerals refer
to like at components of the Type "A" device. This Type "C" working
end 25 has the spring mechanism for sequencing the articulation of
laterally extending elements 45a-45c and 47a-47c eliminated from
the working end. The spring mechanism may be moved to the handle
end or control end of the instrument (not shown).
[0080] FIGS. 12A and 12B show more in particular how each
laterally-extending element may be configured with four living
hinges points 200a, 200b, 200c and 200d to allow electrodes 70 to
assume a face angle at about 900 to axis 15. Each living hinge
point comprises a reduced sectional dimension of the resilient
plastic of the member. Similarly, four living hinges points 202a,
202b, 202c, and 202d allow electrodes 72 to assume a face angle at
about 90.degree. relative to axis 15. FIG. 12B shows that by
varying the lengths of the certain segments of the laterally
extending elements 45a and 47a, electrodes 70 and 72 may be aligned
and opposed at a similar distance D from axis 15. In use, the Type
"C" embodiment is used in a fashion similar as described above.
[0081] This disclosure is illustrative and not limiting. A though
specific features of the invention are shown in some drawings and
not in others, this is for convenience only and any feature may be
combined with another in accordance, with the invention and are
intended to fail within the scope of the appended claims. Other
aspects of the invention are apparent from the drawings and
accompanying descriptions of the instrument and techniques of this
invention which will be readily apparent to a person skilled in the
art that this procedure can be used in many areas of the body in
percutaneous approaches as well as approaches through body orifices
to thermally treat tissues around an anatomic duct.
* * * * *