U.S. patent number 6,283,989 [Application Number 09/280,672] was granted by the patent office on 2001-09-04 for method of treating a bronchial tube with a bronchial stenter having diametrically adjustable electrodes.
This patent grant is currently assigned to Broncus Technolgies, Inc.. Invention is credited to Keith M. Burger, Michael D. Laufer, Bryan E. Loomas, Donald A. Tanaka.
United States Patent |
6,283,989 |
Laufer , et al. |
September 4, 2001 |
Method of treating a bronchial tube with a bronchial stenter having
diametrically adjustable electrodes
Abstract
A device and method for treating collapsed bronchial tubes found
in patients with chronic obstructive pulmonary disease and asthma
are provided. The device delivers energy so that the tissue is
inductively heated by directing electromagnetic energy into the
tissue. The device includes electrodes having adjustable diameters
to enable the electrodes to contact the wall of the bronchial
tubes. The method includes heating the bronchial tube to cause at
least a portion of the cross links of the collagen in the wall to
unlink/open and subsequently form new cross links after the
collagen fibers have realigned. The procedure effectively
reinforces the structural integrity of the wall and thereby
prevents the lumen from collapsing.
Inventors: |
Laufer; Michael D. (Menlo Park,
CA), Burger; Keith M. (San Francisco, CA), Loomas; Bryan
E. (Saratoga, CA), Tanaka; Donald A. (San Jose, CA) |
Assignee: |
Broncus Technolgies, Inc.
(Mountain View, CA)
|
Family
ID: |
21707402 |
Appl.
No.: |
09/280,672 |
Filed: |
March 29, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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003750 |
Jan 7, 1998 |
5972026 |
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833550 |
Apr 7, 1997 |
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Current U.S.
Class: |
607/96; 607/101;
607/105; 607/116 |
Current CPC
Class: |
A61B
18/00 (20130101); A61B 18/1492 (20130101); A61N
1/06 (20130101); A61N 1/403 (20130101); A61B
18/08 (20130101); A61B 18/14 (20130101); A61B
2017/00115 (20130101); A61B 2017/22062 (20130101); A61B
2018/00214 (20130101); A61B 2018/00541 (20130101); A61B
2018/044 (20130101); A61B 2018/046 (20130101); A61B
2018/1807 (20130101) |
Current International
Class: |
A61B
18/14 (20060101); A61B 18/00 (20060101); A61N
1/40 (20060101); A61N 1/06 (20060101); A61B
18/04 (20060101); A61B 18/18 (20060101); A61B
17/00 (20060101); A61F 002/00 () |
Field of
Search: |
;606/2,13-19,27-31,41,42,49-50
;607/88-89,92,96,98,99-102,104,105,116 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 282 225 |
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Sep 1988 |
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EP |
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0 286 145 |
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Oct 1988 |
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EP |
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0 768 091 |
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Apr 1997 |
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EP |
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2 233 293 |
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Jan 1991 |
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GB |
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0 545 358 |
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Jul 1977 |
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SU |
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WO 98/44854 |
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Oct 1998 |
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WO |
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WO 99/03413 |
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Jan 1999 |
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WO |
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Other References
Kitamura, S. Color Atlas of Clinical Appliation of Fiberoptic
Bronchoscopy. Mosby, 1990. p. 17..
|
Primary Examiner: Gibson; Roy
Attorney, Agent or Firm: Morrison & Foerster LLP
Parent Case Text
REFERENCE TO RELATED APPLICATION
This application is a divisional of U.S. Pat. No. 5,972,026 filed
Jan. 7, 1998 and this is a continuation-in-part application of
application Ser. No. 08/833,550 filed Apr. 7, 1997.
Claims
What is claimed is:
1. A method of treating a bronchial tube comprising a lumen of an
individual that comprises the step of:
heating a wall of the lumen to a temperature effective to cause the
wall to undergo a structural transformation to improve the
structural integrity of the wall, the step of heating the wall
comprises advancing a treatment device into the lumen of the
bronchial tube, and activating the treatment device to raise the
temperature of the wall to sufficiently effect a structural
transformation in the wall; and
wherein the treatment device comprises at least one balloon that is
attached to the treatment device wherein each balloon inflates upon
the injection of a fluid into the balloon and each balloon has at
least one electrode that is attached thereto and which when
energized causes the wall of the lumen to undergo a structural
transformation effective to render the wall capable of supporting a
non-collapsed lumen;
a source of fluid having a conduit in fluid communication with said
balloon;
a source of energy; and
means for transmitting energy from the source of energy to the at
least one electrode.
2. The method of claim 1 wherein each electrode is positioned on an
exterior surface of a balloon.
3. The method of claim 1 wherein the source of energy is an RF
generator, and the at least one electrode comprises a first
electrode which is connected to an electrode that is at one
polarity of the RF generator and a second electrode which is
connected to a second RF electrode that is at the opposite polarity
of the RF generator.
4. The method of claim 1 wherein the source of energy produces
energy that is selected from the group consisting of RF energy,
alternating current, and microwaves and combinations thereof.
5. The method of claim 1 wherein the source of energy is an RF
generator, and the treatment device comprises at least three
electrodes.
6. The method of claim 5 wherein said at least three electrodes
includes first electrode(s) that are connected to a positive
electrode of the RF generator and second electrode(s) that are
connected to the negative electrode of the RF generator.
7. The method of claim 5 wherein the treatment device comprises an
external electrode and the RF generator having the first RF
electrode that is at one polarity and the second RF electrode that
is at the opposite polarity and wherein said at least three
electrodes are connected to the first RF electrode and the external
electrode is connected to second RF electrode of the RF
generator.
8. The method of claim 7 wherein the step of activating the
treatment device comprises operating the at least three electrodes
simultaneously.
9. The method of claim 1 wherein the source of energy delivers 1 to
25 watts of power.
10. The method of claim 5 wherein said at least three electrodes
comprises first, second, and third electrodes, and the step of
activating the treatment device comprises the steps of:
connecting the first electrode to the first RF electrode having one
polarity of the RF generator and connecting the second electrode to
the second RF electrode having the opposite polarity of the RF
generator and thereafter activating the RF generator and heating a
first section of wall in the lumen;
deactivating the RF generator;
disconnecting the first electrode from said first RF electrode of
the RF generator; and
connecting the third electrode to said first RF electrode of the RF
generator and thereafter activating the RF generator and heating a
second section of wall of the lumen.
11. The method of claim 1 wherein the wall is heated to a
temperature in the range between about 60.degree. C. and about
95.degree. C.
12. The method of claim 11 wherein the wall is heated to a
temperature in the range between about 70.degree. C. and about
85.degree. C.
13. The method of claim 1 wherein the wall is heated for about 0.1
to about 600 seconds.
14. The method of claim 13 wherein the wall is heated for about 5
to about 60 seconds.
15. A method of treating a bronchial tube comprising a lumen of an
individual that comprises the step of:
heating a wall of the lumen to a temperature effective to cause the
wall to undergo a structural transformation to improve the
structural integrity of the wall, the step of heating the wall
comprises advancing a treatment device into the lumen of the
bronchial tube, and activating the treatment device to raise the
temperature of the wall to sufficiently effect a structural
transformation in the wall; and
wherein the treatment device comprises at least one radially
adjustable electrode;
means for applying force to the at least one radially adjustable
electrode to change the diameter of the at least one electrode;
a source of energy; and
means for transmitting energy from the source of energy to the at
least one electrode.
16. The method of claim 15 wherein the means for applying force
applies torque to the at least one radially adjustable electrode to
change the electrode diameter.
17. The method of claim 15 wherein the means for applying force
changes the axial length of the at least one radially adjustable
electrode.
18. The method of claim 15 wherein the means for applying force
applies torque to the at least one radially adjustable electrode to
change the electrode diameter and changes the axial length of the
at least one radially adjustable electrode.
19. The method of claim 15 wherein the treatment device comprises
an elongated rod that has a distal end, wherein the at least one
radially adjustable electrode comprises a wire that is wound about
and along the axis of the elongated rod and which has a first end
and a second end, wherein the first end is connected to the distal
end of the elongated rod.
20. The method of claim 19 wherein the wire defines a barrel
configuration with a center having a first diameter and two ends
having second and third diameters and wherein the first diameter is
longer than that of the second diameter and of the third
diameter.
21. The method of claim 16 wherein the treatment device comprises
an elongated rod that has a distal end, wherein the treatment
device comprises a plurality of electrodes that are designated the
first electrode, second electrode, and final electrode,
respectively, and that are positioned in tandem so that a first
electrode is attached to the distal end of the elongated rod,
wherein each electrode comprises a wire that is wound about and
along the axis of the elongated rod and each electrode has a first
end and a second end, with the proviso that when the number of
electrodes is two, the treatment device includes a rotatable
coupler which is attached to the second end of the first electrode
and to the first end of the second electrode, and with the further
proviso that when the number of electrodes is three or more, the
electrodes are designated from one to n, and the first end of the
electrode one is connected to the distal end of the elongated rod
and the second end of the electrode n is connected to an end
coupler, and each of the remaining electrodes is connected to an
adjacent electrode by a rotatable coupler.
22. The method of claim 21 wherein the end coupler is
stationary.
23. The method of claim 21 wherein the means for applying force
applies torque that rotates the distal end of the elongated
rod.
24. The method of claim 16 wherein the source of energy is an RF
generator, and the treatment device comprises at least three
electrodes.
25. The method of claim 24 wherein said at least three electrodes
includes first electrode(s) that are connected to a positive
electrode of the RF generator and second electrode(s) that are
connected to the negative electrode of the RF generator.
26. The method of claim 24 wherein the first electrode(s) are
electrically insulated from the second electrode(s).
27. The method of claim 24 wherein the treatment device comprises
an external electrode and the RF generator having the first RF
electrode that is at one polarity and the second RF electrode that
is at the opposite polarity and wherein said at least three
electrodes are connected to the first electrode and the external
electrode is connected to second electrode of the RF generator.
28. The method of claim 15 wherein the source of energy produces
energy that is selected from the group consisting of RF energy,
alternating current, and microwaves and combinations thereof.
29. The method of claim 15 wherein the source of energy delivers 1
to 25 watts of power.
30. The method of claim 25 wherein the step of activating the
treatment device comprises operating the at least three electrodes
simultaneously.
31. The method of claim 24 wherein said at least three electrodes
comprises first, second, and third electrodes, and the step of
activating the treatment device comprises the steps of:
connecting the first electrode to the first RF electrode having one
polarity of the RF generator and connecting the second electrode to
the second RF electrode having the opposite polarity of the RF
generator and thereafter activating the RF generator and heating a
first section of wall in the lumen;
deactivating the RF generator;
disconnecting the first electrode from said first RF electrode of
the RF generator; and
connecting the third electrode to said first RF electrode of the RF
generator and thereafter activating the RF generator and heating a
second section of wall of the lumen.
32. The method of claim 15 wherein the wall is heated to a
temperature in the range between about 60.degree. C. and about
95.degree. C.
33. The method of claim 32 wherein the wall is heated to a
temperature in the range between about 70.degree. C. and about
85.degree. C.
34. The method of claim 15 wherein the wall is heated for about 0.1
to about 600 seconds.
35. The method of claim 34 wherein the wall is heated for about 5
to about 60 seconds.
36. A method of training a person to treat a bronchial tube
comprising a lumen of an individual that comprises demonstrating or
instructing the performance of the following steps:
heating a wall of the lumen to a temperature effective to cause the
wall to undergo a structural transformation to improve the
structural integrity of the wall, the heating step comprises
advancing a treatment device into the lumen of the bronchial tube
of the individual, and activating the treatment device to raise the
temperature of the wall to cause the wall to undergo a structural
transformation; and
wherein the treatment device comprises at least one balloon that is
attached to the treatment device wherein each balloon inflates upon
the injection of a fluid into the balloon and each balloon has at
least one electrode that is attached thereto and which when
energized causes the wall of the lumen to undergo a structural
transformation effective to render the wall capable of supporting a
non-collapsed lumen;
a source of fluid having a conduit in fluid communication with said
balloon;
a source of energy; and
means for transmitting energy from the source of energy to the at
least one electrode.
37. The method of claim 36 wherein the wall is heated to a
temperature in the range between about 60.degree. C. and about
95.degree. C.
38. The method of claim 36 wherein the wall is heated for about 0.1
to about 600 seconds.
39. A method of training a person to treat a bronchial tube
comprising a lumen of an individual that comprises demonstrating or
instructing the performance of the following steps:
heating a wall of the lumen to a temperature effective to cause the
wall to undergo a structural transformation to improve the
structural integrity of the wall, the heating step comprises
advancing a treatment device into the lumen of the bronchial tube
of the individual, and activating the treatment device to raise the
temperature of the wall to cause the wall to undergo a structural
transformation; and
wherein the treatment device comprises at least one radially
expandable electrode;
means for applying force to the at least one radially expandable
electrode to change the diameter of the at least one electrode;
a source of energy; and
means for transmitting energy from the source of energy to the at
least one electrode.
40. The method of claim 39 wherein the wall is heated to a
temperature in the range between about 60.degree. C. and about
95.degree. C.
41. The method of claim 39 wherein the wall is heated for about 0.1
to about 600 seconds.
Description
FIELD OF THE INVENTION
The present invention relates to a device and method for treatment
of the airway obstruction found in chronic obstructive pulmonary
diseases (COPD), such as cystic fibrosis, chronic bronchitis,
emphysema, and asthma.
BACKGROUND OF THE INVENTION
Chronic obstructive pulmonary diseases (COPD), which includes such
entities as cystic fibrosis, chronic bronchitis, and emphysema, are
steadily increasing in frequency, possibly due to continued
smoking, increasing air pollution, and the continued aging of the
population. COPD is characterized by edema of the mucous membranes,
which line the interior walls of the tracheobronchial tree. When
the mucosa accumulates an abnormal quantity of liquid, the profuse
and thickened serous fluid excreted may seriously affect
ventilation in the alveoli. The mucus resists movement up the walls
of the tracheobronchial tree, normally efficiently accomplished by
the cilia throughout the airways which are also destroyed.
Consequently, the serous fluid can form mucus plugs, which can shut
off alveoli or entire airways. In addition to secretion
accumulation, airway obstruction can occur because the tubes
collapse due to destruction of connective tissue. This reduces the
ability to get oxygen into the blood and carbon dioxide out of the
blood.
Asthma is the most common form of bronchoconstrictive disease and
pathologically involves constriction of the bronchioles,
hypertrophy of the muscles of the bronchioles, and a characteristic
infiltrate of eosinophils. Both asthma and COPD, are characterized
by the constriction or collapse of airway passages in the lungs
that are not supported by cartilage. This condition is marked by
labored breathing accompanied by wheezing, by a sense of
constriction in the chest, and often by attacks of coughing and
gasping. Individuals who are afflicted may attempt to compensate by
blowing harder only to have the airways collapse further. A person
with poor resulting ventilation suffers from a number of metabolic
conditions including accumulation of carbon dioxide. These
individuals also often have hyperinflated enlarged lungs and
barrel-shaped chests.
A wide variety of drugs are available for treating the symptoms of
COPD but none is curative. Cystic fibrosis, chronic bronchitis, and
emphysema are typically treated with agents to thin and dry up the
secretions and with antibiotics to combat infection and with
bronchodilators. These drugs include potassium iodide,
antihistamines, various antibiotics, beta agonists and
aminophylline. Unfortunately, a large number of patients are not
responsive to these medications or become non-responsive after
prolonged periods of treatment. For severe cases involving
collapsed air passages, surgeons have endeavored to alleviate this
disabling condition by either removing a portion of the lungs or
constricting the volume of lung available for respiration by
stapling off sections thereof. The result is that functionally the
diaphragm and muscles in the chest wall operate on a smaller lung
volume which may improve air movement for some individuals. These
operations are quite risky and are associated with a large number
of deaths. Patients undergoing these treatments are quite ill and
these procedures are considered final options.
Notwithstanding the conventional treatments available, there exists
a need in the art for an effective treatment for chronic
obstructive pulmonary diseases, such as cystic fibrosis, chronic
bronchitis, emphysema and asthma. Specifically, there is a need for
effective treatment for individuals with obstructed airway passages
to restore pulmonary function which only requires minimal
surgery.
SUMMARY OF THE INVENTION
Many types of tissue can be molded and remodeled to correct defects
and dysfunction. One technique involves physical manipulation using
mechanical instruments and/or balloons to effect selective
shrinking, stretching, flattening, thinning or thickening in
addition to changing the material properties of the tissue. These
changes of properties include alteration of the elastic coefficient
of the tissue causing it to be stiffer, changing the tensile
strength of the tissue, changing the shear strength of the tissue,
and changing the floppiness or resiliency of the tissue. When the
tissue is close to the surface of the skin or part of a non
critical organ, physical manipulation is feasible and can be
executed with minimal trauma to the patient. However, when the
tissue is in an internal organ, in particular, in the lungs or
other vital organ, molding and remodeling by physical manipulation
can involve complicated and often risky surgery.
The present invention is based, in part, on the development of heat
treatment apparatuses having diametrically adjustable electrodes
that are capable of delivering energy to bronchial tubes uniformly.
The heat is preferably inductively applied by directing
electromagnetic energy, such as radio frequency, into the tissue.
The invention also provides for a method for treating a bronchial
tube which comprises the steps of:
a) maneuvering a heating device into the lumen of the bronchial
tube;
b) heating the tissue of the bronchial tube to cause collagen in
the wall of the lumen to undergo a structural transformation
effective to render the wall capable of supporting the lumen
without collapsing; and
c) removing the device from the patent's bronchial tube.
Prior to treatment, the lumen can be non-collapsed, partially, or
fully collapsed. Preferably, the bronchial tube is heated to a
temperature in the range between about 60.degree. C. and about
95.degree. C. for about 0.1 to about 600 seconds. With the
inventive procedure, extensive surgery and the accompanying trauma
are avoided.
This invention is particularly useful for treating subjects
experiencing difficulty in breathing as a result of obstructed
airway passages caused by, for example, chronic obstructive
pulmonary disease, including, for example, cystic fibrosis, chronic
bronchitis, emphysema, and asthma. This invention ameliorates the
affects of these diseases by improving lung function by keeping the
airway passages open. Specifically, the present invention provides
a device and method for effecting changes in collagen-containing
soft tissue in the bronchial tubes or air passages of the lungs
which have collapsed. The causes of the collapse may be the
destruction of the connective tissue, the disease process,
swelling, and/or muscle-dependant constriction. The invention is
directed to a treatment process which effectively creates an
internal bronchial stent which prevents the air passages from
collapsing. As used herein, the term "bronchial tube" or "air
passage" refers to the sub-segments that branch from the main stem
bronchus of the lungs. The term "collapsed lumen" refers to a
condition of lumen of a bronchial tube wherein the lumen is
occluded to the extent that substantial blockage of air flow
through the lumen exists. The diameter of a non-collapsed lumen may
be substantially equal to that of a normal bronchial tube or may be
less as in the case of a partially collapsed but functional lumen.
It is understood that the term "collapsed lumen" encompasses
partially collapsed lumens. Cartilage is not present around these
air passages in appreciable amounts so they have little intrinsic
supportive structures.
In one aspect, the invention is directed to an apparatus, for
treating a bronchial tube having a lumen, which includes:
(a) a treatment device comprising at least one balloon that is
attached to a the treatment device wherein each balloon inflates
upon the injection of a fluid into the balloon and each balloon has
at least one electrode that is attached thereto and which when
energized causes collagen in the wall of the lumen to undergo a
structural transformation effective to render the wall capable of
supporting a non-collapsed lumen;
(b) a source of fluid;
(c) a source of energy; and
(d) means for transmitting energy from the source of energy to the
at least one electrode.
In another aspect, the invention is directed to an apparatus, for
treating a bronchial tube having a lumen, which includes:
(a) a treatment device comprising at least one balloon that is
attached to a the treatment device wherein each balloon inflates
upon the injection of a fluid into the balloon and each balloon has
at least one electrode that is attached thereto and which when
energized causes collagen in the wall of the lumen to undergo a
structural transformation effective to render the wall capable of
supporting a non-collapsed lumen;
(b) a source of fluid;
(c) a source of energy; and
(d) means for transmitting energy from the source of energy to the
at least one electrode.
BRIEF DESCRIPTION OF THE DRAWINGS
As used herein, like reference numerals will designate similar
elements in the various embodiments of the present invention
wherein:
FIGS. 1A and 1B show an embodiment of the heat treatment apparatus
of the present invention which employs electrodes positioned on the
outer surface of a balloon, FIG. 1B is an enlarged view of the
distal end of the device shown in FIG 1A;
FIGS. 2, 3, and 4 show embodiments of the heat treatment apparatus
which employ diametrically adjustable electrodes;
FIGS. 5 and 6 are cross-sectional views of a bronchoscope with a
heat treatment apparatus device positioned therein; and
FIG. 7 shows an embodiment of the heat treatment apparatus with
multiple electrodes; and
FIG. 8 shown an embodiment of the heat treatment apparatus with
multiple balloons.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1A and 1B shows an embodiment of the heat treatment apparatus
which includes balloon 100 that is positioned at or near the distal
end of elongated rod 110 which is positioned within the lumen or
aperture 251 of catheter sheath 250. It is understood that the term
"rod" also encompasses tubes which have hollow channels. As shown,
the balloon with inner surface 101 is in the inflated state having
been inflated with an appropriate fluid such as air or saline that
is injected from conduit 130 and into the interior of the balloon
through aperture 131 in the rod. The apparatus includes electrodes
102 and 104 which are spaced apart along the outer perimeter of the
inflated balloon. It is understood that the number of electrodes
and their configurations on the outer surface of the balloon can be
varied. These electrodes come into contact with the wall of the
lumen when the balloon is inflated. The electrodes employed in the
present invention can have different configurations. For example,
the electrodes can be conventional coil wires with round cross
sections, or they can have a non-round configuration, such as, for
example, a thin, foil or band with a rectangular cross section. For
the device shown in FIG. 1B, electrodes 102 and 104 are preferably
flat bands each extending around the circumference of the balloon.
To permit expansion of the balloon, each band is positioned around
the outer surface of the balloon with the two ends overlapping each
other. As shown the FIG. 1B, electrode 102 is a band having ends
103 and 113 with a portion of the band adjacent to end 103
overlapping a portion of the band adjacent to end 113. Similarly,
electrode 104 is a band having overlapping ends 105 and 115.
Balloons suitable for the present invention may be of similar
material and design as those currently being used in percutaneous
transluminal angioplasty. For a review of the state of the art, see
U.S. Pat. Nos. 4,807,620; 5,057,106; 5,190,517; 5,281,218;
5,314,466; 5,370,677; 5,370,678; 5,405,346; 5,431,649; 5,437,664;
5,447,529; and 5,454,809 all incorporated herein by reference. The
balloon is preferably fabricated of a non-elastic material that is
substantially impermeable to the fluid. In this fashion, the
balloon can be designed to have a more uniform cross section and a
fixed maximum diameter when the balloon is fully inflated. This
provides better contact of the electrodes to the wall of the
bronchial tube. Suitable non-elastic materials include, for
example, polyester (e.g., MYLAR) and polyethylene. When the balloon
is fully inflated, the length of its diameter is preferably 1 mm to
300 mm, and more preferably about 3 mm to 5 mm.
It is understood that the balloon can also be made of elastic
material such as silicone, natural latex, and polyethylene. With
elastic material balloons, the degree of expansion is proportional
to the amount of force introduced into the interior of the balloon.
Moreover, the balloon preferably will substantially return to its
original, non-expanded form when the internal force is
released.
The balloon of the heat treatment apparatus is preferably
constructed of non-elastic material that is initially folded and/or
collapsed. In this non-inflated state, the diameter of the balloon
is small enough that the balloon can be positioned inside an
aperture or working channel of a bronchoscope. In use, the
bronchoscope first is positioned at the treatment site before the
balloon to exposed and then inflated. Heat treatment is then
commenced.
The present invention is based in part on the discovery that the
structural integrity of bronchial tubes, especially those which do
not have significant amounts of cartilage present, can be
significantly recreated by subjecting the bronchial tubes to a
sufficient amount of heat to cause at least a portion of the cross
links of the collagen fibers to open and subsequently form new
cross links after the collagen fibers have realigned thereby
causing the tubes to remain patent. This procedure changes the
structure of the integral collagen and the shape of the tube.
FIGS. 1A and 1B show that electrodes 102 and 104 are connected via
cables 122 and 142, respectively, to a radio frequency (RF)
generator 130 with controls 138. Rod 110 is also connected to
syringe 150 which is employed to inject a fluid from source 146
through valve 148 into the balloon.
The frequency range of RF radiation useful in the present invention
is typically about 10 KHZ to about 100 MHZ, preferably in the range
of about 200 KHZ to about 800 KHZ. However, frequencies outside
this range may be used at the discretion of the operating surgeon.
Typically, the amount of power employed will be from about 0.01 to
100 watts and preferably in the range of about 1 to 25 watts.
Alternatively, alternating current or microwave radiation typically
in the frequency range of about 1,000 MHz to about 2,000 MHz and
preferably from about 1,100 MHZ to about 1,500 MHz may be used in
place of RF radiation. In the latter case, the RF generator 130 is
replaced with a microwave generator, and the cables 122 and 142 are
replaced with waveguides.
In use, after the operating surgeon has placed the heat treatment
apparatus within the lumen of a bronchial tube to be treated, the
balloon is first exposed and then inflated with fluid from syringe
150 located conveniently for the surgeon. In the case where the
lumen of the bronchial tube has collapsed or is partially
collapsed, the balloon is preferably inflated until the lumen has
expanded to its normal diameter with the balloon in substantial
contact with the inner surface of the lumen. Alternatively, in the
case where the lumen has not collapsed, the balloon is preferably
inflated until it is in substantial contact with the inner surface
of the lumen. Indeed, only minimum inflation of the balloon may be
necessary in treating a non-collapsed bronchial lumen which has a
diameter that is about equal to, or less than that of the outer
surface of the uninflated balloon.
The amount of inflation of the balloon is determined by the
operating surgeon who monitors the balloon expansion by means of
endoscopy or by other suitable imaging methods of the art.
Generally, the heat required is induced in the tissue of the
bronchial tube wall by the RF or microwave radiation emitting from
the electrodes. The RF or microwave energy would be applied while
observing for changes via simultaneous endoscopy, or other suitable
imaging methods of the art.
As is apparent, the inventive heat treatment apparatuses can be
employed to treat a bronchial tube regardless of whether its lumen
has collapsed or not. Specifically, the devices can be used to
treat bronchial tubes that have not collapsed, are partially
collapsed, or are fully collapsed. Moreover, bronchial tubes may
exhibit different degrees of closure depending on the state of
respiration. For example, a bronchial tube may have a fully
expanded lumen after inhalation but partially or completely closed
during exhalation.
FIG. 2 shows another embodiment of the inventive heat treatment
apparatus which includes a pair of electrode coils 210 and 220 that
are positioned in tandem. The number of electrode coils is not
critical. The apparatus also includes an elongated rod 230 which
has a distal end 231 that is connected to a tip or knob 240 and has
a proximal end which is at least partially slidably positioned
inside aperture 251 of catheter sheath 250 that includes end
coupler 235. Coil 210 has two ends, the first end 211 being
attached to knob 240 and the second end 212 is attached to
rotatable or floating coupler 270. Similarly, coil 220 has two
ends, the first end 221 is attached to rotatable coupler 270 and
the second end 222 is attached to end coupler 235.
As shown in FIG. 2, the coils are in the relaxed state which is
meant that no torque is being applied to either coil. In this
state, each coil has a "barrel" configuration so that the diameter
of the outer contour formed by each coil is largest at its center
and smallest at its two ends. A number of preferred methods can be
employed to change the diameters of the contour. One method is to
compress or expand the coils along the axis. For example, by
pushing rod 230 outward so that knob 240 extends away from catheter
sheath 250, the coil diameters will decrease. Another method of
changing the diameter is to apply torque to the coils. Torque can
be applied by rotating the rod in a clockwise or counterclockwise
direction while keeping end coupler 235 stationary, e.g., attached
to the inner surface of catheter sheath. Torque can also be applied
by keeping rod 230 stationary while rotating end coupler 235.
Alternatively, torque can be applied by rotating the rod in one
direction while rotation end coupler 235 in the opposite direction.
During the rotation process, rotatable coupler 270 will also rotate
to thereby transfer torque from one coil to the other.
In practice, applying torque to adjust the radial diameters of the
coils is preferred over compressing or pulling the coils lengthwise
since applying torque creates less of a gradient in the diameter of
each coil. According, preferably, the treatment apparatus is
constructed so that end coupler 235 remains stationary. Torque is
preferably applied by manually rotating rod 230. When more than one
coil is employed, a rotatable coupler is required to connect
adjacent coils. Multiple coil configurations are preferred over one
with a single coil that has the same length (in the relaxed state)
as the sum of the lengths of the smaller coils since the diameters
of the smaller coils will tend to be more uniform and in contact
with the wall of the bronchial tube being treated. Each coil in the
embodiment shown in FIG. 2 is connected to an appropriate source of
energy. For example, coils 210 and 220 can be connected by lines
215 and 225 to a radio frequency generator 130 as shown in FIG.
1A.
In operation, the heat treatment apparatus is positioned at the
treatment site before the diameters of the coils are adjusted by
applying torque. Energy is then applied to the coils.
FIGS. 3 and 4 show embodiments of the inventive heat treatment
apparatus that are similar to the one of FIG. 2. The apparatus of
FIG. 3 includes a pair of electrode coils 310 and 320 that are
positioned in tandem. The apparatus also includes an elongated rod
230 which has a distal end 331 that is connected to a tip or knob
340 and has a proximal end which is at least partially slidably
positioned inside aperture 251 of catheter sheath 250 that includes
end coupler 235. Coil 310 has two ends, the first end 311 being
attached to knob 340 and the second end 312 is attached to
rotatable coupler 370. Similarly, coil 320 has two ends, the first
end 321 is attached to rotatable coupler 370 and the second end 322
is attached to end coupler 235. As is apparent, each electrode has
a cone-shaped contour and comprises a coil that is wound about and
along the axis of the rod 230 and which in the relaxed state has a
large diameter at one end and a small diameter at the other
end.
The apparatus of FIG. 4 includes a pair of electrode coils 410 and
420 that are positioned in tandem. The apparatus also includes an
elongated rod 230 which has a distal end 431 that is connected to a
tip or knob 440 and has a proximal end which is at least partially
slidably positioned inside aperture 251 of catheter sheath 250 that
includes end coupler 235. Coil 410 has two ends, the first end 411
being attached to knob 440 and the second end 412 is attached to
rotatable coupler 470. Similarly, coil 420 has two ends, the first
end 421 is attached to rotatable coupler 470 and the second end 422
is attached to end coupler 235. As is apparent, each electrode has
a single loop configuration that comprises a coil that is wound
once about the rod 230. In this configuration, the two electrodes
when in the relaxed state preferably form loops having the same
diameter.
The devices of FIGS. 3 and 4 operate in essentially the same manner
as the device of FIG. 2. Specifically, the same methods can be
employed to adjust the radial diameter of the coils by compressing
or pulling the coils or by applying torque to the coils. In
addition, each coil is connected to an appropriate source of
energy. For example, coils 210 and 220 can be connected by lines
215 and 225 to a radio frequency generator 130 as shown in FIG.
1A.
The electrodes employed in the present invention are constructed of
a suitable current conducting metal or alloys such as, for example,
copper, steel, and platinum. The electrodes can also be constructed
of a shape memory alloy which is capable of assuming a
predetermined, i.e., programmed, shape upon reaching a
predetermtined, i.e., activation, temperature. Such metals are well
known in the art as described, for example, in U.S. Pat. Nos.
4,621,882 and 4,772,112 which are incorporated herein. For the
present invention, the shape memory metal used should have the
characteristic of assumings a deflection away (i.e., expands) from
the elongated rod when activated, i.e., heated in excess of the
normal body temperature and preferably between 60.degree. C. and
95.degree. C. A preferred shape memory alloy is available as
NITINOL from Raychem Corp., Menlo Park, Calif. For the heat
treatment apparatuses that employ coils as shown in FIGS. 2-4,
preferably the electrodes are constructed of NITINOL in a
predetermined shape and in the alloy's super elastic phase which
can withstand very large deflections without deformation.
The above embodiments illustrate systems that employ bipolar
electrodes. In each system, the electrodes emit RF energy with one
conductive element acting as the active electrode and the other
acting, as the return electrode, or vice versa. One electrode would
be connected to the positive electrode of the generator and the
other would be connected to the negative electrode. An insulator is
located between the conductive elements. In general, when operating
in the bipolar mode, electrodes that have different polarities are
electrically insulated from each other.
When the heat treatment device with the bipolar electrodes is
positioned inside the lumen of a bronchial tube, activation of the
RF generator causes collagen containing tissue in the lumen wall to
increase in temperature. The particular heat pattern in the tissue
will depend on the path of the electric field created.
Alternatively, heat treatment apparatuses employing a unipolar
electrode can also be employed. For instance, in the case of the
embodiment shown in FIGS. 1A and 1B, the heating device can have
one or more inner electrodes 102 and/or 104 on the balloon surface
and an outer or external electrode 188 that has a much larger
surface area than that of the internal electrode(s) and that is
placed on the outer surface of the patient's body. For example, the
external electrode can be an external metal mesh or solid plate
that is placed on the skin. Both the internal and external
electrodes are connected to an RF generator which produces an
electric field at a high frequency within the balloon. Because the
collective surface area of the internal electrode(s) is much
smaller than that of the outer electrode, the density of the high
frequency electric field is much higher around the internal
electrode(s). The electric field reaches its highest density in the
region near the internal electrode(s). The increased density of the
field around the internal electrode(s) produces localized heating
of the tissue.
The function of the treating element, i.e., electrodes, is to apply
a sufficient amount of energy to the walls of air passages to cause
collagen in the walls to undergo a structural transformation to
create more rigid walls that can support a non-collapsed, patent
lumen. RF energy is no longer applied after there has been
sufficient transformation, e.g., shrinkage, of the collagen fibers
which may be gauged by removing the heating device from the
treatment site and visually determining whether the lumen remains
noncollapsed. Sufficient shrinkage may also be detected by
fluoroscopy, external ultrasound scanning, pulse-echo ultrasound
scanning, sensing the collapsing or straightening of the heating
element with appropriate feedback variables, impedance monitoring
or any other suitable method.
Substantial transformation may be achieved very rapidly, depending
upon the specific treatment conditions. Because the transformation
can proceed at a rather rapid rate, the RF energy should be applied
at low power levels. Preferably, the RF energy is applied for a
length of time in the range of about 0.1 second to about 600
seconds, and preferably about 5 to about 60 seconds. Suitable RF
power sources are commercially available and well known to those
skilled in the art. In one embodiment the RF generator employed has
a single channel, delivering approximately 1 to 100 watts,
preferably 1 to 25 watts, and most preferably 2 to 8 watts of RF
energy and possessing continuous flow capability. The rate of
collagen transformation can be controlled by varying the energy
delivered to the heating element. Regardless of the source of
energy used during treatment, the lumen or the bronchial tube is
maintained at a temperature of at least about 60.degree. C.,
preferably between 60.degree. C. to 95.degree. C. and more
preferably between 70.degree. C. to 85.degree. C.
As is apparent, the heat treatment device of the present invention
can comprise more than one electrode that is positioned at or near
the distal end of the elongated rod. For example, FIG. 7 depicts
schematically the distal end 700 of a heat treatment device which
comprises electrodes 701, 702, and 703. In this configuration if
the device operates in the bipolar mode, two of the three
electrodes (e.g., 701 and 702) are connected to one pole of the RF
generator and the other electrode (702) is connected to the other
pole. Heat will be generated in the tissue adjacent the region
between electrodes 701 and 702 and the region between electrodes
702 and 703. These electrodes 701, 702, and 703 can be attached to
the exterior surface of a balloon, alternatively they represent
adjustable coils in embodiments that do not require a balloon.
When the heat treatment device includes multiple electrodes, not
all the electrodes need to be activated at the same time, that is,
different combinations of electrodes can be employed sequentially.
For example, in the case of the above described bipolar embodiment
with three electrodes, electrodes 701 and 702 can be first
activated to heat a section of the bronchial tube wall. During the
heat treatment, electrode 703 can also be activated so that a
second section of the bronchial tube wall is heat treated
simultaneously. Alternatively, electrode 701 is disconnected to the
RF generator before electrode 703 is activated so that the second
section is treated subsequent to treatment of the first
section.
In addition, when a heat treatment device includes multiple
electrodes, the device can operate in the monopolar, bipolar mode,
or both modes at the same time. For instance, electrodes 701 and
702 can be designed to operate in the bipolar mode while electrode
703 is designed to operate in the monopolar mode. As a further
variation, the electrodes can be constructed of different materials
and/or constructed to have different configurations. For example,
electrode 701 can be made of a shape memory alloy and/or it can be
a coil while each of the other electrodes 702 and 703 can be made
of a non-shape memory material and/or it can be a band with a
rectangular cross section.
The heat treatment device of the present invention can comprise
more than one balloon that is attached to the elongated rod. For
example, FIG. 8 depicts schematically the distal end of a heat
treatment device which comprises balloons 810 and 820. Electrodes
811 and 812 are attached to the exterior surface of balloon 810 and
electrodes 821 and 822 are attached to the exterior surface balloon
820. The device includes an elongated rod 860 which is positioned
with the lumen of catheter sheath 850. This device is preferably
constructed in the same manner as the device shown in FIG. 1B
except for the additional balloon. Operation of the device is also
similar although the surgeon has the choice of activating both sets
of electrode simultaneously or one set at a time.
When treating a person with obstructed air passages, a preliminary
diagnosis is made to identify the air passages or bronchial tube
that can be treated. In treating a particular site, excessive fluid
is first removed from the obstructed air passage by conventional
means such as with a suction catheter. Thereafter, the inventive
heat treatment device is maneuvered to the treatment site.
Depending on the diameter of the lumen of the bronchial tube, the
device can be positioned directly at the treatment site or it can
be positioned into place with a bronchoscope. The elongated rod and
outer catheter of the device are made of a flexible material so
that it can be maneuvered through a bronchoscope. A bronchoscope is
a modified catheter which is an illuminating instrument for
inspecting and passing instruments (e.g., the treatment device)
into the bronchial tubes.
FIGS. 4 and 5 illustrate a bronchoscope 430 having a heat treatment
apparatus 470 slidably positioned within a lumen. The device also
includes an image-transmitting fiber 450 and illuminating fiber
452. Any conventional bronchoscope with an appropriately sized and
directed working lumen may be employed. The image transmitting
fiber collects light from the distal end of the treating apparatus
and directs the light to a viewing apparatus (not shown) for
displaying an image of the obstructed air passage. The bronchoscope
may have a panning system which enables the tips to be moved in
different directions.
In operation, the bronchoscope is advanced from the person's nasal
or oral cavity, and through the trachea, main stem bronchus, and
into an obstructed air passage. The heat treatment apparatus is
advanced forward from the bronchoscope to expose the tip containing
the treatment device before the treatment device is energized.
Depending on the size of the treatment device, the treatment device
can be moved to another position for further heat treatment of the
air passage. This process can be repeated as many times as
necessary to form a series of patency bands supporting an air
passage. This procedure is applied to a sufficient number of air
passages until the physician determines that he is finished. As is
apparent, the procedure can be completed in one treatment or
multiple treatments. After completion of the treatment, energy is
discontinued and the treatment device is removed from the
patient.
The heating apparatus can be made to provide protection against
overheating of the connective tissue which will cause the collagen
to denature. Temperature monitoring and impedance monitoring can be
utilized in a system which provides feedback to the user in the
form of sounds, lights, other displays or which shuts down the
application of energy from the heating element to the treatment
site when sufficient transformation is detected and to avoid
burning of the treatment site. The amount of energy applied can be
decreased or eliminated manually or automatically under certain
conditions. For example, the temperature of the wall of the air
passage, or of the heating element can be monitored and the energy
being applied adjusted accordingly. The surgeon can, if desired,
override the feedback control system. A microprocessor can be
included and incorporated into the feedback control system to
switch the power on and off, as well as to modulate the power. The
microprocessor can serve as a controller to monitor the temperature
and modulate the power.
The invention is also directed to the demonstration or instruction
of the inventive surgical techniques including, but not limited to,
written instructions, actual instructions involving patients,
audio-visual presentations, animal demonstrations, and the
like.
While several particular embodiments of the invention have been
illustrated and described, it will be apparent that various
modifications can be made without departing from the spirit and
scope of the invention. Accordingly, it is not intended that the
invention be limited. except as by the appended claims.
* * * * *