U.S. patent application number 10/234762 was filed with the patent office on 2003-01-16 for loop structures for positioning a diagnostic or therapeutic element on the epicardium or other organ surface.
Invention is credited to Koblish, Josef V., Swanson, David K., Thompson, Russell B., Whayne, James G..
Application Number | 20030014049 10/234762 |
Document ID | / |
Family ID | 27555859 |
Filed Date | 2003-01-16 |
United States Patent
Application |
20030014049 |
Kind Code |
A1 |
Koblish, Josef V. ; et
al. |
January 16, 2003 |
Loop structures for positioning a diagnostic or therapeutic element
on the epicardium or other organ surface
Abstract
Loop structures for positioning diagnostic an therapeutic
elements on the epicardium or other organ surface.
Inventors: |
Koblish, Josef V.;
(Sunnyvale, CA) ; Thompson, Russell B.; (Los
Altos, CA) ; Whayne, James G.; (San Jose, CA)
; Swanson, David K.; (Campbell, CA) |
Correspondence
Address: |
HENRICKS SLAVIN AND HOLMES LLP
SUITE 200
840 APOLLO STREET
EL SEGUNDO
CA
90245
|
Family ID: |
27555859 |
Appl. No.: |
10/234762 |
Filed: |
September 3, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10234762 |
Sep 3, 2002 |
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09535625 |
Mar 24, 2000 |
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6464700 |
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09535625 |
Mar 24, 2000 |
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09017465 |
Feb 2, 1998 |
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6071274 |
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09535625 |
Mar 24, 2000 |
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09072872 |
May 5, 1998 |
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6142994 |
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09072872 |
May 5, 1998 |
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08949084 |
Oct 10, 1997 |
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09072872 |
May 5, 1998 |
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08321092 |
Oct 11, 1994 |
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5836947 |
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08321092 |
Oct 11, 1994 |
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08320198 |
Oct 7, 1994 |
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Current U.S.
Class: |
606/41 ; 600/374;
606/49; 607/99 |
Current CPC
Class: |
A61B 2018/00148
20130101; A61B 2018/00797 20130101; A61B 2018/1253 20130101; A61B
2018/00136 20130101; A61B 2018/0016 20130101; A61B 2018/00214
20130101; A61B 18/1482 20130101; A61B 18/1815 20130101; A61B
2018/126 20130101; A61B 2018/0091 20130101; A61B 2017/22038
20130101; A61B 2018/00577 20130101; A61B 2018/00101 20130101; A61B
2018/1475 20130101; A61B 2018/00083 20130101; A61B 2018/00351
20130101; A61B 2018/00821 20130101; A61B 2018/124 20130101; A61B
2018/1407 20130101; A61B 2018/00952 20130101; A61B 2018/00916
20130101; A61B 2018/142 20130101; A61B 18/1492 20130101; A61N 1/056
20130101; A61B 2017/2911 20130101; A61B 2018/00946 20130101 |
Class at
Publication: |
606/41 ; 606/49;
600/374; 607/99 |
International
Class: |
A61B 018/14 |
Claims
We claim:
1. A surgical device, comprising: a relatively short outer member
defining an interior bore, a proximal portion, a distal portion and
a distal opening; a relatively short shaft defining a main body
portion and a distal portion, located at least partially within the
interior bore of the relatively short outer member and slidable
relative to the relatively short outer member; a control element
defining a distal portion connected to the distal portion of the
relatively short shaft and a proximal portion extending toward the
proximal portion of the relatively short outer member; and an
operative element on the distal portion of the relatively short
shaft.
2. A surgical device as claimed in claim 1, wherein the control
element comprises a pull wire.
3. A surgical device as claimed in claim 1, wherein the operative
element comprises a plurality of spaced electrodes.
4. A surgical device as claimed in claim 1, further comprising: a
mask element associated with the operative element.
5. A surgical device as claimed in claim 1, wherein the control
element extends along the exterior of the relatively short shaft
within the relatively short outer member.
6. A surgical device as claimed in claim 5, wherein the relatively
short outer member comprises a tubular member.
7. A surgical device as claimed in claim 5, wherein the relatively
short outer member is relatively stiff.
8. A surgical device as claimed in claim 5, wherein the main body
portion of the relatively short shaft is relatively stiff.
9. A surgical device as claimed in claim 5, wherein the distal
portion of the relatively short shaft is flexible.
10. A surgical device as claimed in claim 5, wherein the distal
portion of the relatively short shaft includes a flexible region
and a malleable region.
11. A surgical device as claimed in claim 1, wherein the control
element extends along the exterior of the relatively short outer
member.
12. A surgical device as claimed in claim 11, wherein the
relatively short outer member includes a control element guide.
13. A surgical device as claimed in claim 12, wherein the control
element guide comprises an eyelet.
14. A surgical device as claimed in claim 12, wherein the control
element guide includes a flared portion defining a plurality of
apertures.
15. A surgical device as claimed in claim 14, wherein the flared
portion defines an outer edge and includes a plurality of slots
extending from the outer edge to respective apertures.
16. A surgical device as claimed in claim 11, wherein the
relatively short outer member includes a lock adapted to fix the
position of the relatively short shaft relative to the relatively
short outer member.
17. A surgical device as claimed in claim 11, wherein the
relatively short outer member includes a tie post.
18. A surgical device as claimed in claim 1, wherein the distal
portion of the relatively short shaft includes longitudinally
spaced shaft indicia and the relatively short outer member includes
outer member indicia that interrelates with the shaft indicia in
such a manner that the shaft indicia visible when a region of the
distal portion of the relatively short shaft extends outwardly from
the distal opening and the outer member indicia together indicate
how much of the distal portion of the relatively short shaft
remains within the relatively short outer member.
19. A surgical device as claimed in claim 18, wherein the operative
element comprises a plurality of electrodes, the shaft indicia
comprises first shaft indicia associated with a first electrode,
and the distal member indicia comprises first distal member indicia
corresponding to the first shaft indicia.
20. A surgical device as claimed in claim 19, wherein the shaft
indicia further comprises second shaft indicia associated with a
second electrode and the distal member indicia comprises second
distal member indicia corresponding to the second shaft
indicia.
21. A surgical device as claimed in claim 20, wherein a third
electrode is located distal of the first and second electrodes.
22. A surgical device as claimed in claim 18, wherein the shaft
indicia comprises at least one colored ring and the outer member
indicia comprises a least one colored ring.
23. A surgical device as claimed in claim 1, wherein the relatively
short outer member defines a first relatively short outer member,
the surgical device further comprising: a second relatively short
outer member defining an interior bore, a proximal portion, a
distal portion and a distal opening, and being arranged relative to
the first relatively short outer member such that the distal
portion of the relatively short shaft may be advanced outwardly
from the distal opening of the first relatively short outer member
into the distal opening of the second relatively short outer member
to define a loop.
24. A surgical device as claimed in claim 23, wherein the first and
second relatively short outer members are secured to one
another.
25. A surgical device as claimed in claim 23, wherein the distal
openings of the first and second relatively short outer members
face in different directions.
26. A surgical device as claimed in claim 23, wherein the first
relatively short outer member defines a substantially linear
longitudinal axis and the second relatively short outer member
defines a curved longitudinal axis.
27. A surgical device as claimed in claim 23, wherein the second
relatively short outer member includes a slot.
28. A surgical device as claimed in claim 23, wherein the distal
opening of at least one of the first and second relatively short
outer members is outwardly flared.
29. A surgical device as claimed in claim 23, wherein the first
relatively short outer member includes a lock adapted to fix the
position of the relatively short shaft relative to the relatively
short outer member.
30. A surgical device as claimed in claim 23, wherein the first
relatively short outer member includes a tie post.
31. A surgical device as claimed in claim 23, wherein the first
relatively short outer member is relatively stiff.
32. A surgical device as claimed in claim 23, wherein the operative
element comprises a plurality of spaced electrodes.
33. A surgical device as claimed in claim 1, wherein the operative
element comprises a tip electrode having a pair of exterior
openings.
34. A surgical device as claimed in claim 33, wherein the exterior
openings are connected by a through hole extending through the tip
electrode.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of co-pending
U.S. application Ser. No. 09/072,872, filed May 5, 1998, which is
itself (1) a continuation-in-part of U.S. application Ser. No.
08/321,092, filed Oct. 11, 1994, now U.S. Pat. No. 5,836,947, which
is a continuation-in-part of U.S. application Ser. No. 08/320,198,
filed Oct. 7, 1994, now abandoned, and (2) of U.S. application Ser.
No. 08/949,084, filed filed Oct. 10, 1997.
[0002] This application is also a continuation-in-part of
co-pending U.S. application Ser. No. 09/017,465, filed Feb. 2,
1998.
[0003] The specification and claims of each of these applications
are incorporated herein by reference.
BACKGROUND OF THE INVENTIONS
[0004] 1. Field of Inventions
[0005] The present inventions relate generally to structures for
positioning diagnostic and therapeutic elements within the body
and, more particularly, to devices which are particularly well
suited for the treatment of cardiac conditions.
[0006] 2. Description of the Related Art
[0007] There are many instances where diagnostic and therapeutic
elements must be inserted into the body. One instance involves the
treatment of cardiac conditions such as atrial fibrillation and
atrial flutter which lead to an unpleasant, irregular heart beat,
called arrhythmia.
[0008] Normal sinus rhythm of the heart begins with the sinoatrial
node (or "SA node") generating an electrical impulse. The impulse
usually propagates uniformly across the right and left atria and
the atrial septum to the atrioventricular node (or "AV node"). This
propagation causes the atria to contract in an organized way to
transport blood from the atria to the ventricles, and to provide
timed stimulation of the ventricles. The AV node regulates the
propagation delay to the atrioventricular bundle (or "HIS" bundle).
This coordination of the electrical activity of the heart causes
atrial systole during ventricular diastole. This, in turn, improves
the mechanical function of the heart. Atrial fibrillation occurs
when anatomical obstacles in the heart disrupt the normally uniform
propagation of electrical impulses in the atria. These anatomical
obstacles (called "conduction blocks") can cause the electrical
impulse to degenerate into several circular wavelets that circulate
about the obstacles. These wavelets, called "reentry circuits,"
disrupt the normally uniform activation of the left and right
atria.
[0009] Because of a loss of atrioventricular synchrony, the people
who suffer from atrial fibrillation and flutter also suffer the
consequences of impaired hemodynamics and loss of cardiac
efficiency. They are also at greater risk of stroke and other
thromboembolic complications because of loss of effective
contraction and atrial stasis.
[0010] Although pharmacological treatment is available for atrial
fibrillation and flutter, the treatment is far from perfect. For
example, certain antiarrhythmic drugs, like quinidine and
procainamide, can reduce both the incidence and the duration of
atrial fibrillation episodes. Yet, these drugs often fail to
maintain sinus rhythm in the patient. Cardioactive drugs, like
digitalis, Beta blockers, and calcium channel blockers, can also be
given to control the ventricular response. However, many people are
intolerant to such drugs. Anticoagulant therapy also combats
thromboembolic complications, but does not eliminate them.
Unfortunately, pharmacological remedies often do not remedy the
subjective symptoms associated with an irregular heartbeat. They
also do not restore cardiac hemodynamics to normal and remove the
risk of thromboembolism.
[0011] Many believe that the only way to really treat all three
detrimental results of atrial fibrillation and flutter is to
actively interrupt all of the potential pathways for atrial reentry
circuits.
[0012] One surgical method of treating atrial fibrillation by
interrupting pathways for reentry circuits is the so-called "maze
procedure" which relies on a prescribed pattern of incisions to
anatomically create a convoluted path, or maze, for electrical
propagation within the left and right atria. The incisions direct
the electrical impulse from the SA node along a specified route
through all regions of both atria, causing uniform contraction
required for normal atrial transport function. The incisions
finally direct the impulse to the AV node to activate the
ventricles, restoring normal atrioventricular synchrony. The
incisions are also carefully placed to interrupt the conduction
routes of the most common reentry circuits. The maze procedure has
been found very effective in curing atrial fibrillation. However,
the maze procedure is technically difficult to do. It also requires
open heart surgery and is very expensive. Thus, despite its
considerable clinical success, only a few maze procedures are done
each year.
[0013] Maze-like procedures have also been developed utilizing
catheters which can form lesions on the endocardium to effectively
create a maze for electrical conduction in a predetermined path.
Exemplary catheters are disclosed in commonly assigned U.S. Pat.
No. 5,582,609. Typically, the lesions are formed by ablating tissue
with an electrode carried by the catheter. Electromagnetic radio
frequency ("RF") energy applied by the electrode heats, and
eventually kills (i.e. "ablates"), the tissue to form a lesion.
During the ablation of soft tissue (i.e. tissue other than blood,
bone and connective tissue), tissue coagulation occurs and it is
the coagulation that kills the tissue. Thus, references to the
ablation of soft tissue are necessarily references to soft tissue
coagulation. "Tissue coagulation" is the process of cross-linking
proteins in tissue to cause the tissue to jell. In soft tissue, it
is the fluid within the tissue cell membranes that jells to kill
the cells, thereby killing the tissue.
[0014] Catheters used to create lesions (the lesions being 3 to 15
cm in length) typically include a relatively long and relatively
flexible body portion that has an electrode on its distal end. The
portion of the catheter body portion that is inserted into the
patient is typically from 23 to 55 inches in length and there may
be another 8 to 15 inches, including a handle, outside the patient.
The proximal end of the catheter body is connected to the handle
which includes steering controls. The length and flexibility of the
catheter body allow the catheter to be inserted into a main vein or
artery (typically the femoral artery), directed into the interior
of the heart, and then manipulated such that the electrode contacts
the tissue that is to be ablated. Fluoroscopic imaging is used to
provide the physician with a visual indication of the location of
the catheter.
[0015] Catheter-based soft tissue coagulation has proven to be a
significant advance in the medical arts generally and in the
treatment of cardiac conditions in particular. Nevertheless, the
inventors herein have determined that catheter-based procedures are
not appropriate in every situation and that conventional catheters
are not capable of reliably forming all types of lesions. One
lesion that has proven to be difficult to form with conventional
catheters is the circumferential lesion that is used to isolate a
pulmonary vein and cure ectopic atrial fibrillation. Lesions that
isolate the pulmonary vein may be formed within the pulmonary vein
itself or in the tissue surrounding the pulmonary vein. These
circumferential lesions are formed by dragging a tip electrode
around the pulmonary vein or by creating a group of interconnected
curvilinear lesions one-by-one around the pulmonary vein. Such
techniques have proven to be less than effective because they are
slow and gaps of conductive tissue can remain after the procedure.
It can also be difficult to achieve adequate tissue contact with
conventional catheters.
[0016] Endocardial lesions to isolate pulmonary veins have also
been formed as a secondary procedure during a primary open heart
surgical procedure such as mitral valve replacement. A surgical
soft tissue coagulation probe is used to form the endocardial
lesions after the heart has been opened, either before or after the
valve replacement. This technique does, however, increase the
amount of time the patient is on pulmonary bypass, which can be
undesirable.
[0017] Accordingly, the inventors herein have determined that a
need exists for surgical methods and apparatus that can be used to
create lesions around bodily structures and, in the context of the
treatment of atrial fibrillation, around a pulmonary vein without
increasing the amount of time that the patient is on pulmonary
bypass.
SUMMARY OF THE INVENTIONS
[0018] Accordingly, the general object of the present inventions is
to provide methods and apparatus that avoid, for practical
purposes, the aforementioned problems. In particular, one object of
the present inventions is to provide surgical methods and apparatus
that can be used to create lesions around a pulmonary vein or other
body structure in a more efficient manner than conventional
apparatus. Another object of the present inventions is to provide
surgical methods and apparatus that may be used to create lesions
around a pulmonary vein without placing the patient on pulmonary
bypass or increasing the amount of time that the patient is on
pulmonary bypass when a related procedure is being performed. Still
another object of the present inventions is to perform a diagnostic
or therapeutic procedure, such as the coagulation of tissue around
a body structure, without effecting collateral tissue that is not
targeted for the procedure.
[0019] In order to accomplish some of these and other objectives, a
surgical device in accordance with a present invention includes a
relatively short outer member, a relatively short shaft located at
least partially within the relatively short outer member and
slidable relative to the relatively short outer member, and an
operative element on the distal portion of the relatively short
shaft. The distal portion of the relatively short shaft is adapted
to be connected to the distal portion of the relatively short outer
member such that the distal portion of the shaft member will form a
loop.
[0020] In order to accomplish some of these and other objectives, a
surgical device in accordance with a present invention includes a
relatively short outer member, a relatively short shaft located at
least partially within the relatively short outer member and
slidable relative to the relatively short outer member, a control
element defining a distal portion connected to the distal portion
of the relatively short shaft and a proximal portion extending
toward the proximal portion of the relatively short outer member,
and an operative element on the distal portion of the relatively
short shaft. The distal portion of the relatively short shaft may
be used to form a loop.
[0021] In order to accomplish some of these and other objectives, a
surgical device in accordance with a preferred embodiment of a
present invention includes a relatively short shaft and a distal
member having a flexible region and a malleable region and an
operative element carried by the distal member. Preferably, the
distal tip assembly may, if desired, also include a pull wire that
facilitates the formation of a loop.
[0022] In order to accomplish some of these and other objectives, a
clamp device in accordance with a preferred embodiment of a present
invention includes first and second curved members and a tissue
coagulation apparatus associated with the first and second curved
members. The curved members and tissue coagulation apparatus
preferably together define an open region that may be positioned
around a body structure such as one or more pulmonary veins.
[0023] Such devices provide a number of advantages over the
conventional devices used to create lesions around pulmonary veins.
For example, the operative element carrying loops and the first and
second curved members may be positioned around a pulmonary vein (or
veins) on the epicardial surface in accordance with inventive
methods disclosed herein. A continuous transmural lesion that will
isolate the vein may then be created while the heart is beating.
The heart need not be opened and pulmonary bypass is not required.
As such, the present devices advantageously allow curative lesions
to be formed around pulmonary veins without the difficulties
associated with catheter-based procedures or the time on pulmonary
bypass required by conventional surgical procedures.
[0024] In order to accomplish some of these and other objectives, a
mask element for masking an operative element supported on a
support body in accordance with a present invention includes a main
body with a side wall defining an interior bore and a side wall
opening. The mask element, which is preferably formed from
thermally and electrically insulating material, is adapted to be
positioned on the support structure such that a portion of the
operative element is aligned with the side wall opening and a
portion of the operative element is covered by the side wall. When
the support structure is positioned with the side wall opening (and
exposed portion of the operative element) facing the target tissue
region, the remainder of the operative element will be covered by
the side wall. As such, the present mask element protects
non-target collateral tissue from being damaged, sensed or
otherwise affected by the operative element.
[0025] The above described and many other features and attendant
advantages of the present inventions will become apparent as the
inventions become better understood by reference to the following
detailed description when considered in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Detailed description of preferred embodiments of the
inventions will be made with reference to the accompanying
drawings.
[0027] FIGS. 1A and 1B are partial plan views together showing a
surgical device in accordance with a preferred embodiment of a
present invention.
[0028] FIG. 1C is a partial section view of the distal portion of
the shaft illustrated in FIG. 1B.
[0029] FIG. 2 is a side view of the outer member illustrated in
FIG. 1B.
[0030] FIG. 3 is an end view of the outer member illustrated in
FIG. 1B.
[0031] FIG. 4 is a section view taken along line 4-4 in FIG.
1B.
[0032] FIG. 5 is a perspective view showing the surgical device
illustrated in FIGS. 1A-1C being used in a surgical procedure
involving the heart.
[0033] FIGS. 6A and 6B are partial plan views together showing a
surgical device in accordance with a preferred embodiment of a
present invention.
[0034] FIG. 7A is a plan view of a portion of a surgical device in
accordance with a preferred embodiment of a present invention.
[0035] FIG. 7B is a partial section view of the distal portion of
the shaft illustrated in FIG. 7A.
[0036] FIGS. 8A and 8B are partial plan views together showing a
surgical device in accordance with a preferred embodiment of a
present invention.
[0037] FIG. 8C is a partial section view of the distal portion of
the shaft illustrated in FIG. 8B. FIG. 9A is a perspective view of
the exemplary anchoring device illustrated in FIG. 8B.
[0038] FIGS. 9B-9D are perspective views of other exemplary
anchoring devices.
[0039] FIG. 10 is a side, partial section view of a pull wire guide
and electrode support structure in accordance with a preferred
embodiment of a present invention.
[0040] FIG. 11 is a perspective view of the pull wire guide
illustrated in FIG. 10.
[0041] FIG. 12 is a perspective view of a pull wire guide in
accordance with a preferred embodiment of a present invention.
[0042] FIGS. 13A and 13B are partial plan views together showing a
surgical device in accordance with a preferred embodiment of a
present invention.
[0043] FIG. 14 is a plan view of a surgical device in accordance
with a preferred embodiment of a present invention.
[0044] FIG. 15 is a section view taken along line 15-15 in FIG.
14.
[0045] FIG. 16 is a section view taken along line 16-16 in FIG.
14.
[0046] FIG. 17A is a partial side view of a distal structure that
may be used in conjunction with a surgical device such as that
illustrated in FIGS. 14 and 17C.
[0047] FIG. 17B is a side view of another distal structure that may
be used in conjunction with a surgical device such as that
illustrated in FIGS. 14 and 17C.
[0048] FIG. 17C is a plan view of a surgical device in accordance
with a preferred embodiment of a present invention.
[0049] FIG. 17D is a perspective view of a tip electrode in
accordance with a preferred embodiment of a present invention.
[0050] FIG. 17E is a side view of the tip electrode illustrated in
FIG. 17D.
[0051] FIG. 17F is a partial perspective view of another tip
electrode.
[0052] FIG. 18 is a plan view showing a portion of a surgical
device and electrode identification system in accordance with a
preferred embodiment of a present invention.
[0053] FIG. 19 is an exploded perspective view of a mask element in
accordance with a preferred embodiment of a present invention.
[0054] FIG. 20 is an exploded side view of the mask element
illustrated in FIG. 19 in combination with a surgical device that
carries a plurality of electrodes.
[0055] FIG. 21 is a front plan view of a clamp device in accordance
with a preferred embodiment of a present invention.
[0056] FIG. 22 is an enlarged rear plan view of a portion of the
clamp device illustrated in FIG. 21.
[0057] FIG. 23 is a section view taken along line 23-23 in FIG.
21.
[0058] FIG. 24 is a section view taken along line 24-24 in FIG.
21.
[0059] FIG. 25 is a plan view of a clamp device in accordance with
a preferred embodiment of a present invention.
[0060] FIG. 26 is a perspective view of a portion of a heart with
lesions formed in accordance with a therapeutic method in
accordance with a present invention.
[0061] FIG. 27 is a perspective view of a portion of a heart with a
lesion formed in accordance with a therapeutic method in accordance
with a present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0062] The following is a detailed description of the best
presently known modes of carrying out the inventions. This
description is not to be taken in a limiting sense, but is made
merely for the purpose of illustrating the general principles of
the inventions.
[0063] The detailed description of the preferred embodiments is
organized as follows:
[0064] I. Loop Structures With Coupling Devices
[0065] II. Loop Structures With Coupling Devices And Pull Wires
[0066] III. Loop Structures With Pull Wires
[0067] IV. Operative Elements, Temperature Sensing And Power
Control
[0068] V. Operative Element Identification
[0069] VI. Masking
[0070] VII. Clamp Devices
[0071] VIII. Methods
[0072] The section titles and overall organization of the present
detailed description are for the purpose of convenience only and
are not intended to limit the present inventions.
[0073] This specification discloses a number of structures, mainly
in the context of cardiac ablation, because the structures are well
suited for use with myocardial tissue. Nevertheless, it should be
appreciated that the structures are applicable for use in therapies
involving other types of soft tissue. For example, various aspects
of the present inventions have applications in procedures
concerning other regions of the body such as the prostate, liver,
brain, gall bladder, uterus and other solid organs.
[0074] I. Loop Structures With Coupling Devices
[0075] As illustrated for example in FIGS. 1A and 1B, a surgical
device 10 in accordance with a preferred embodiment of a present
invention includes a shaft 12 that is preferably formed from two
tubular parts, or members. The proximal member 14 is attached to a
handle 16 while the distal member 18, which is shorter than the
proximal member, carries an operative element such as the
illustrated plurality of spaced electrodes 20. The proximal member
14 is typically formed from a biocompatible thermoplastic material
that is thermally and electrically insulating, such as a Pebax.RTM.
material (polyether block amide). The distal member 18 is typically
formed from a softer, more flexible biocompatible thermoplastic
material that is also thermally and electrically insulating, such
as Pebax.RTM. material, polyethylene, or polyurethane. The proximal
and distal members, which are about 5 French to about 9 French in
diameter, are preferably either bonded together with an overlapping
thermal bond or adhesively bonded together end to end over a sleeve
in what is referred to as a "butt bond."
[0076] The shaft 12 in the exemplary surgical device 10 extends
through the interior bore of an outer member 22 in the manner
illustrated in FIGS. 1A and 1B. The outer member 22 is preferably a
tubular structure that includes a available under the name
Nitinol), braided Spectran.RTM. or Keviar.RTM. fibers, or common
suture materials. Suitable materials for the eyelet 28 include
Nitinol, 17-7 stainless steel, Spectran.RTM. and Kevlar.RTM.. It
should also be noted that the locations of the hook 26 and eyelet
28 may be reversed.
[0077] The core wire 32 is anchored at the proximal end of the
shaft 12, while the core wire and eyelet 28 are both anchored at
the distal end of the shaft. Referring to FIG. 1C, the proximal
portion of the eyelet 28 and the distal portion of the core wire 32
are secured to one another with a crimp tube 27 in the exemplary
embodiment. The crimp tube 27 is soldered, welded or otherwise
bonded to a tip anchor 29 that is mounted on the distal end of the
distal member 18. An insulating sleeve 31 is also provided along
the length of the distal member 18.
[0078] Although the core wire 32 is preferably circular in
cross-section, the portion of the core wire within the distal
member 18 may have a rectangular (or other non-circular shape)
cross-section in order to control the bending plane of the distal
member. This technique is especially useful when portions of the
electrodes 20 are masked using one of the techniques described in
Section VI below.
[0079] As illustrated for example in FIG. 5, one use of the
exemplary surgical device 10 involves the creation of an epicardial
lesion around a pair of pulmonary veins PV. The shaft 12 and outer
member 22 are directly inserted into the patient's chest and the
shaft distal member 18 may be threaded around a pair of pulmonary
veins PV with hemostats or other surgical instruments. An
adjustable loop 33 is formed by placing the eyelet 28 over the hook
26. The loop 33 may be tightened around the pulmonary veins PV by
holding the outer member 22 and pulling the shaft 12 in the
proximal direction. Relative movement of the shaft 12 and outer
member 22 can be prevented with the locking device 24 to maintain
the loop 33 in the desired size. Once the loop 33 has been
accurately positioned, some or all of the electrodes 20 may be used
to create a transmural epicardial lesion around the pulmonary veins
PV. Additional information concerning methods of creating
epicardial lesions is provided in Section VIII below. locking
device 24, such as the illustrated Toughy Borst fitting, at the
proximal end to fix the position of the shaft 12 relative to the
outer member. The outer member 22 also preferably includes a flared
inner surface 23 (FIG. 2) to facilitate movement of the electrodes
20 into the outer member. Alternatively, the distal end of the
outer member may be formed from relatively soft material. With
respect to materials, the outer member 22 may be formed from a
thermally and electrically insulating biocompatible thermoplastic
material such as Pebax.RTM. material.
[0080] The shaft 12 and outer member 22 are both relatively short.
The term "relatively short" is used in the present specification to
describe a length that is suitable for direct placement against the
targeted tissue region during a surgical procedure. "Relatively
long" shafts, on the other hand, include conventional catheter
shafts that are guided through the vasculature to a target tissue
region. In the context of the surgical procedures involving the
heart, access to the targeted tissue region may be obtained by way
of a thoracotomy, median sternotomy, or thoracostomy. As such, the
length of the shaft 12 is preferably between about 6 inches and
about 30 inches, with the proximal member 14 being between about 3
inches and about 20 inches, and the distal member 18 being between
about 3 inches and about 20 inches. The length of the outer member
22 is only about 2 inches to about 10 inches.
[0081] A loop may be formed by securing the distal end of the shaft
12 to the distal end of the outer member 22 and a fastening
apparatus is provided that allows the distal ends to be releasably
secured to one another. The fastening apparatus in the illustrated
embodiment consists of a hook 26 on the distal end of the outer
member 22 and an eyelet 28 on the distal end of the shaft 12.
Referring more specifically to FIGS. 2 and 3, the hook 26 is
mounted on a cylindrical base 30 that is itself mounted on the
exterior of the distal end of the outer member 22 The base 30,
which along with the hook 26 is preferably formed from metal or
plastic, may be secured to the outer member 22 through the use of
adhesive, welding or other suitable methods. The eyelet 28 is
anchored to a flexible internal core wire 32 (FIG. 4) that may be
formed from resilient inert wire, such as stranded or solid nickel
titanium (commercially
[0082] In order to allow the distal member 18 to be tightly
threaded around a relatively small structure such as a pulmonary
vein, the distal member is preferably very flexible. As used
herein, the term "very flexible" refers to distal members which are
more flexible than the distal portions of conventional diagnostic
and steerable electrophysiology catheters, which must be stiff
enough to force electrodes against tissue.
[0083] The exemplary handle 16 illustrated in FIG. 1A consists of
two molded handle halves and is provided with strain relief element
36 and a PC board 38. As discussed in greater detail in Section IV
below, there is a temperature sensor associated with each
longitudinal edge of the electrodes 20 in the illustrated
embodiment. Signal wires 41 (FIG. 4) are connected to the
electrodes 20 and signal wires 42 are connected to the temperature
sensors. The signal wires are passed in conventional fashion
through a lumen extending through the shaft 12 to the PC board 38.
The PC board 38 is, in turn, electrically coupled to a connector
that is received in a port at the proximal end of the handle 16.
The connector plugs into a source of RF coagulation energy.
[0084] Another exemplary device, which is generally represented by
reference numeral 40, is illustrated in FIGS. 6A and 6B. Many
structural elements in the exemplary device 40 are similar to those
in the exemplary device 10 and such elements are represented by the
same reference numerals. For example, the exemplary device 40
includes a relatively short shaft 12 with a proximal member 14 and
a distal member 18 that supports a plurality of electrodes 20 or
some other operative element. Exemplary device 40 also includes a
handle 16 and a hook 26 and eyelet 28 arrangement.
[0085] The primary difference between the two surgical devices is
that the exemplary device 40 includes a relatively short outer
member 42 that is relatively stiff. In other words, the outer
member is either rigid, malleable, or somewhat flexible. A rigid
outer member cannot be bent. A malleable outer member is a outer
member that can be readily bent by the physician to a desired
shape, without springing back when released, so that it will remain
in that shape during the surgical procedure. Thus, the stiffness of
a malleable outer member must be low enough to allow the outer
member to be bent, but high enough to resist bending when the
forces associated with a surgical procedure are applied to the
outer member. A somewhat flexible outer member will bend and spring
back when released. However, the force required to bend the outer
member must be substantial. Rigid and somewhat flexible shafts are
preferably formed from stainless steel, while malleable shafts are
formed from annealed stainless steel. Additional information
concerning malleable structures may be found in aforementioned U.S.
application Ser. No. 09/072,872.
[0086] A rigid or somewhat flexible outer member 42 may be linear
or formed with one or more bends 44 designed for a particular
surgical procedure, as is illustrated for example in FIG. 6B. The
physician may place bends in a malleable outer member 42 in order
to facilitate proper placement of the distal end of the outer
member.
[0087] II. Loop Structures With Coupling Devices and Pull Wires
[0088] It may be difficult in some instances to thread the shaft
distal member 18 around an anatomical structure such as a pulmonary
vein. As such, the distal end of the shaft 12 may be provided with
a pull wire 34, as is illustrated for example FIG. 7A. The pull
wire 34, which is thinner and more flexible than the shaft distal
member 18, will be easier to thread around anatomical structures.
After the pull wire 34 has been threaded around a pulmonary vein or
other structure, and around the hook 26, the pull wire may be used
to pull the shaft distal member 18 around the structure to form a
loop. Suitable materials for the pull wire 34, which is typically
more flexible than the core wire 32, include stranded Nitinol,
Spectran.RTM. and Kevlar.RTM..
[0089] The pull wire 34 may be secured to the core wire 32 with a
crimp tube or other suitable device in the manner illustrated, for
example, in FIG. 7B. More specifically, the proximal portions of
the eyelet 28 and pull wire 34 and the distal portion of the core
wire 32 are secured to one another with a crimp tube 27. The crimp
tube 27 is soldered, welded or otherwise bonded to a tip anchor 29
that is mounted on the distal end of the distal member 18.
[0090] Ill. Loop Structures With Pull Wires
[0091] As illustrated for example in FIGS. 8A and 8B, a surgical
device 46 in accordance with a preferred embodiment of a present
invention includes many structural elements similar to those in the
exemplary devices illustrated in FIGS. 1A-7B and such elements are
represented by the same reference numerals. For example, the
exemplary surgical device 46 includes a relatively short shaft 12
with a proximal member 14 and a distal member 18 that supports a
plurality of electrodes 20 or some other operative element. The
proximal end of the shaft 12 is secured to a handle 16.
[0092] As illustrated for example in FIG. 8C, a pull wire 34
similar to that illustrated in FIGS. 7A and 7B is crimped to the
core wire 32 with a crimp tube 27 and the crimp tube is secured to
a tip anchor 29' by bonding, welding or other suitable methods.
Here, however, the tip anchor 29' has a closed distal end and the
pull wire 34 is threaded through an opening 33 in the anchor.
Alternatively, the core wire 32 and pull wire 34 may be replaced
with a single, continuous pull/core wire (not shown).
[0093] The exemplary surgical device 46 does not, however, include
an outer member with a coupling device that secures the distal
portion of the outer member to the shaft distal member 18. Instead,
surgical device 46 includes a relatively short outer member 48 with
a pull wire guide 50. The outer member 48 also includes a flared
inner surface (not shown) or soft material at its distal end and a
locking device 24, such as a Toughy Borst fifting, at its proximal
end to fix the position of the shaft 12. The pull wire 34 may be
threaded through the pull wire guide 50 to form a loop 51 and then
secured to an anchoring device 52. The loop 51 may then be adjusted
by moving the shaft 12 and outer member 48 relative to one another
or by adjusting the pull wire 34. In one exemplary procedure, the
pull wire 34 will be threaded around a pair of pulmonary veins
prior to being threaded through the pull wire guide 50 to form a
loop similar to that illustrated in FIG. 5.
[0094] With respect to the physical characteristics of the outer
member 48, the outer member is preferably formed from relatively
high durometer materials (72D and above) such as braided or
unbraided Pebax.RTM. or Nylon material that is stiffer than the
distal member 18 as well as thermally and electrically insulating.
The outer member 48 should also be slightly shorter (i.e. 1 to 2
inches shorter) than the proximal member 14.
[0095] As illustrated in FIGS. 8B and 9A, the exemplary anchoring
device 52 includes a main body 54 that is mounted on the outer
member 48, a post 56 and a cap 58. The cap 58 includes a pair of
slots 60. The pull wire 34 is wound around the post 56 and then
through the slots 60 to anchor it in place. The anchoring device 52
is preferably formed from molded plastic. An alternate anchoring
device 52', with a slightly differently shaped cap 58', is
illustrated in FIG. 9B. Still other anchoring devices, which are
represented by reference numerals 53 and 53', are illustrated in
FIGS. 9C and 9D. Here, slots 55 extend through caps 57 and 57' and
into the posts 56 on which the caps are mounted. The flexibility of
the plastic material allows the pull wire 34 to be pulled down
through into slot 55 and then held in place through friction and
mechanical interference.
[0096] In the exemplary embodiment illustrated in FIGS. 8A-8C, the
pull wire guide 50 is an eyelet or other simple loop or hook
structure formed from metal or plastic that is mounted on a
cylindrical base 62. Alternatively, as illustrated in FIGS. 10 and
11, a pull wire guide 64 may be provided with a plurality of pull
wire openings 66 that extend around the periphery of the distal end
of the outer member 48. This arrangement facilitates the threading
of a pull wire through the pull wire guide 64 regardless of the
rotational orientation of the outer member 48 relative to the
physician and patient and also eliminates the need for the
rotational orientation to be closely monitored and/or adjusted
prior to loop formation.
[0097] The exemplary pull wire guide 64 illustrated in FIGS. 10 and
11, which may be formed from metal or plastic, includes a base 68
and an outwardly flared member 70 in which the openings 66 are
located. The base 68 has a mounting surface 72 with a shape
corresponding to that of the outer member on which it is mounted,
i.e. cylindrical in the illustrated embodiment, and a smooth curved
lip 74 that should extend inwardly from the mounting surface a
distance that is at least equal to the wall thickness of the outer
member. The flared member 70 includes a plurality of supports 75
and a peripheral ring 76 that together define the pull wire
openings 66. The flared member 70 also has a smooth inner surface
78 that, together with the smooth curved lip 74, facilitates
movement of the electrodes 20 or other operative elements through
the pull wire guide 64 and into the outer member 48.
[0098] Turning to FIG. 12, the exemplary pull wire guide 80
illustrated therein is substantially similar to the guide
illustrated in FIGS. 10 and 11 and similar structural elements are
represented by similar reference numerals. Here, however, the
peripheral ring 76 in the flared member 70 has been replaced by a
plurality of a peripheral members 82 in a flared member 70' that
define slots 84 therebetween. The slots 84 allow a pull wire to be
slipped into the openings 66 instead of threaded through the
openings. The peripheral members 82 also include curved, inwardly
extending end portions 86 that prevent the pull wire from sliding
out of the openings 66 once it is located therein.
[0099] Another exemplary surgical device, which is generally
represented by reference numeral 88, is illustrated in FIGS. 13A
and 13B. Like the exemplary surgical device 46 illustrated in FIGS.
8A-8C, surgical device 88 includes a shaft 12, with a proximal
member 14 secured to handle 16 and a distal member 18 that supports
electrodes 20 or some other operative element, and a pull wire 34.
However, instead of a single relatively short outer member,
surgical device 88 includes an outer member assembly 90 with a pair
of outer members 92 and 94. A loop 95 is formed by directing the
shaft distal member 18 outwardly from the distal end of outer
member 92 and into the distal end of the outer member 94. The pull
wire 34 may be anchored with an anchoring member 52 and the shaft
12 held in place relative to the outer member 92 with a locking
device 24. The outer members are preferably formed from stainless
steel or molded polymer material and have a inner diameter of about
7 French and an outer diameter of about 10 French.
[0100] The configuration of the loop 95 formed by the distal member
18 is primarily determined by the shape and relative orientation of
the outer members 92 and 94. In the illustrated embodiment, outer
member 92 is linear and outer member 94 is curved. The outer
members 92 and 94, which are held in place relative to one another
by a post 96 and weld (not shown) in region 98, are oriented such
that the distal ends thereof define an angle of about 45 degrees.
Of course, the curvatures of the outer members 92 and 94, as well
as the relative orientation thereof, may be adjusted to suit
particular needs.
[0101] In order to facilitate formation and adjustment of the loop
95, outer member 94 includes a pull wire slot 100 and the distal
ends of the outer members 92 and 94 respectively include outwardly
flared portions 102 and 104. The pull wire slot 100 is wide enough
to allow the pull wire 34 to slide into the outer member 94, yet
too narrow to allow the shaft distal member 18 to slide out of the
outer member once it has been pulled in. As such, loop 95 may be
formed by advancing the shaft distal member 18 outwardly from the
distal end of the outer member 92, pulling on the pull wire 34 to
bend the distal member back in the proximal direction, sliding the
pull wire into the pull wire slot 100, and pulling the distal
member into the distal end of the outer member 94.
[0102] As illustrated for example in FIGS. 14-16, a surgical device
106 in accordance with another preferred embodiment includes a
relatively short shaft 108, a handle 16, and a distal section 110.
The shaft 108 consists of a hypo-tube 112, which is either rigid or
relatively stiff (preferably malleable), and an outer polymer
tubing 114 over the hypo-tube. The distal section 110 is preferably
somewhat flexible, in that it will conform to a surface against
which it is pressed and then spring back to its original shape when
removed from the surface. Surgical device 106 also includes a pull
wire 34. The pull wire 34 is pre-threaded between the hypo-tube 112
and outer tubing 114 and through an aperture in the handle.
Alternatively, the pull wire 34 may be threaded through a pull wire
guide in the manner described above.
[0103] Referring more specifically to FIGS. 15 and 16, the
exemplary distal section 110 preferably includes a spring member
116, which is preferably either a solid flat wire spring (as
shown), a round wire, or a three leaf flat wire Nitinol spring,
that is connected to the distal end of the hypo-tube 112 by welding
or a crimp tube. Other spring members, formed from materials such
as 17-7 or carpenter's steel, may also be used. As noted above,
signal wires 41 and 42 connect the electrode 20 and temperature
sensor elements to the PC board 38. The spring member 116 and
signal wires 41 and 42 are enclosed in a flexible body 118,
preferably formed from Pebaxo.RTM. material, polyurethane, or other
suitable materials. The spring member 116 may also be pre-stressed
so that the distal tip is pre-bent. An insulating sleeve 120 may be
placed between the spring member 116 and the lead wires 41 and 42
if desired.
[0104] The distal section 110 may, alternatively, have a malleable
portion. As illustrated for example in FIG. 17A, the spring member
116 (FIG. 16) is replaced with a shorter, but otherwise identical
spring member 116' and a tapered malleable member 122 that is
secured to the-hypotube 112 by welding or other suitable methods.
In a preferred implementation having seven electrodes, the
malleable member 122 will extend to fourth electrode (counting
proximal to distal), although this may be varied depending on the
intended application. The spring member 116' and malleable member
122 may be secured to one another with a stainless steel crimp tube
124, which is soldered or otherwise bonded to the malleable member
and mechanically coupled to the spring member with crimps 126.
Suitable materials for the malleable member 122 include stainless
steel.
[0105] The malleable portion within the distal section 110 may also
be provided in the manner illustrated in FIG. 17B. Here, the spring
member 116' is secured to malleable hypotube 121 with, for example,
crimps 123. The hypotube 121 is secured to the hypotube 112 by
welding or other suitable methods. One particular advantage of this
arrangement is that the relative lengths of the malleable and
flexible regions may be varied during manufacture by simply varying
the length of the hypotube 121.
[0106] Probes having distal sections with both malleable and
flexible regions may also be provided without a pull wire. The
exemplary probe 106' illustrated in FIG. 17C is essentially
identical to the probe 106 illustrated in FIG. 14. Here, however,
the pull wire 34 and outer tubing 114 have been eliminated and a
tip electrode 125 has been added.
[0107] Referring to FIGS. 17D and 17E, the tip electrode 125
preferably includes a through hole 127 that allows
instrumentalities, such as suture material or one-quarter inch
umbilical tape, to be threaded through the electrode to form a pull
wire-like device if desired. The through hole 127 may also be
engaged by a towel clamp formed from non-conducting material, or
other similar device, during a procedure to allow the physician to
push or pull from either end of the probe 106' for positioning and
pressure application purposes. For example, after the suture
material has been used to pull the probe 106' around an organ such
as the heart, a towel clamp may be used to grab the distal end of
the probe for more accurate positioning.
[0108] The ends of the through hole 127 are preferably chamfered
and, as illustrated in FIG. 17E, the through hole may extend
straight through the tip electrode 125. Alternatively, as
illustrated in FIG. 17F, electrode 125' includes a through hole
127' with two portions arranged at an angle to one another. A lumen
129, having a large diameter portion and a small diameter portion
(in which temperature sensors may be located), extends through the
base 131 and into the interior of the tip electrode 125. The base
131 is inserted into the end of the distal section 110 during
assembly.
[0109] It should be noted that a tip electrode with a through hole,
such as those illustrated in FIGS. 17D-17F, may be used in
combination with other probes, including those illustrated in FIGS.
1-13 of the present application. The exemplary electrodes
illustrated in FIGS. 17C-17F have an outer diameter of about 2.7 mm
and are about 8 mm in length. The size and shape of the tip
electrode may, of course, be varied as desired to suit particular
applications.
[0110] There are a number of advantages associated with probes
having a distal section with both malleable and flexible regions.
For example, the combination of malleable and flexible regions in
the distal section 110 allows a single probe to form a wide variety
of lesions. The relatively stiff, malleable region of the distal
section 110 may be shaped to conform to anatomical structures on,
for example, the surface of the heart. Direct pressure may then be
applied to the structure during the formation of continuous lesions
(note lesion 152 in FIG. 26) or segmented lesion patterns. The
flexible region of the distal section 110 may be wrapped around
anatomical structures such as, for example, pulmonary veins (note
lesions 202 and 204 in FIG. 26). The malleable and flexible regions
may also be used in conjunction with one another by, for example,
shaping the malleable region to suit a particular procedure prior
to wrapping the flexible region around an anatomical structure.
[0111] A probe with a combination of malleable and flexible regions
in the distal section 110 may also be used in combination with the
relatively short outer member 48 illustrated in FIG. 8B.
[0112] IV. Operative Elements, Temperature Sensing And Power
Control
[0113] In each of the preferred embodiments, the operative element
is a plurality of spaced electrodes 20. However, other operative
elements, such as lumens for chemical ablation, laser arrays,
ultrasonic transducers, microwave electrodes, and ohmically heated
hot wires, and the like may be substituted for the electrodes.
[0114] The spaced electrodes 20 are preferably in the form of
wound, spiral coils. The coils are made of electrically conducting
material, like copper alloy, platinum, or stainless steel, or
compositions such as drawn-filled tubing (e.g. a copper core with a
platinum jacket). The electrically conducting material of the coils
can be further coated with platinum-iridium or gold to improve its
conduction properties and biocompatibility. A preferred coil
electrode is disclosed in U.S. Pat. No. 5,797,905.
[0115] As an alternative, the electrodes may be in the form of
solid rings of conductive material, like platinum, or can comprise
a conductive material, like platinum-iridium or gold, coated upon
the device using conventional coating techniques or an ion beam
assisted deposition (IBAD) process. For better adherence, an
undercoating of nickel, silver or titanium can be applied. The
electrodes can also be in the form of helical ribbons. The
electrodes can also be formed with a conductive ink compound that
is pad printed onto a non-conductive tubular body. A preferred
conductive ink compound is a silver-based flexible adhesive
conductive ink (polyurethane binder), however other metal-based
adhesive conductive inks such as platinum-based, gold-based,
copper-based, etc., may also be used to form electrodes. Such inks
are more flexible than epoxy-based inks.
[0116] The flexible electrodes 20 are preferably about 4 mm to
about 20 mm in length. In the preferred embodiment, the electrodes
are 12.5 mm in length with 1 mm to 3 mm spacing, which will result
in the creation of continuous lesion patterns in tissue when
coagulation energy is applied simultaneously to adjacent
electrodes. For rigid electrodes, the length of the each electrode
can vary from about 2 mm to about 10 mm. Using multiple rigid
electrodes longer than about 10 mm each adversely effects the
overall flexibility of the device, while electrodes having lengths
of less than about 2 mm do not consistently form the desired
continuous lesion patterns.
[0117] The electrodes 20 may be operated in a uni-polar mode, in
which the soft tissue coagulation energy emitted by the electrodes
is returned through an indifferent patch electrode (not shown)
externally attached to the skin of the patient. Alternatively, the
electrodes may be operated in a bi-polar mode, in which energy
emitted by one or more electrodes is returned through other
electrodes. The amount of power required to coagulate tissue ranges
from 5 to 150 w.
[0118] As illustrated for example in FIG. 10, a plurality of
temperature sensors 128, such as thermocouples or thermistors, may
be located on, under, abutting the longitudinal end edges of, or in
between, the electrodes 20. Preferably, the temperature sensors 128
are located at the longitudinal edges of the electrodes 20 on the
side of the structure intended to face the tissue. In some
embodiments, a reference thermocouple 130 (FIG. 14) may also be
provided. For temperature control purposes, signals from the
temperature sensors are transmitted to the source of coagulation
energy by way of wires 42 (FIG. 4) that are also connected to the
aforementioned PC board 38 in the catheter handle. Suitable
temperature sensors and controllers which control power to
electrodes based on a sensed temperature are disclosed in U.S. Pat.
Nos. 5,456,682, 5,582,609 and 5,755,715.
[0119] The temperature sensors are also preferably located within a
linear channel (not shown) that is formed in the distal member. The
linear channel insures that the temperature sensors will directly
face the tissue and be arranged in linear fashion. The illustrated
arrangement results in more accurate temperature readings which, in
turn, results in better temperature control. As such, the actual
tissue temperature will more accurately correspond to the
temperature set by the physician on the power control device,
thereby providing the physician with better control of the lesion
creation process and reducing the likelihood that embolic materials
will be formed. Such a channel may be employed in conjunction with
any of the electrode (or other operative element) supporting
structures disclosed herein.
[0120] Finally, the electrodes 20 and temperature sensors 128 can
include a porous material coating, which transmits coagulation
energy through an electrified ionic medium. For example, as
disclosed in U.S. Pat. No. 5,991,650, electrodes and temperature
sensors may be coated with regenerated cellulose, hydrogel or
plastic having electrically conductive components. With respect to
regenerated cellulose and other micro-porous materials, the coating
acts as a mechanical barrier between the surgical device
components, such as electrodes, preventing ingress of blood cells,
infectious agents, such as viruses and bacteria, and large
biological molecules such as proteins, while providing electrical
contact to the human body. The micro-porous material coating also
acts as a biocompatible barrier between the device components and
the human body, whereby the components can now be made from
materials that are somewhat toxic (such as silver or copper).
[0121] V. Operative Element Identification
[0122] Certain power source and control devices, such as the
Cobra.RTM. electrosurgical unit manufactured by EP Technologies,
Inc., allow the physician to individually select which of the
electrodes 20 will be supplied with power. In a seven electrode
arrangement, for example, the power supply and control device will
include seven on-off switches that respectively correspond to the
seven electrodes 20. Such an arrangement allows the physician to
selectively enable only those electrodes that, for example, are
located outside the outer member 22 after a loop has been formed
around an anatomical structure. Nevertheless, it can be difficult
for the physician to accurately determine how many of the
electrodes are outside the outer member 22 during a surgical
procedure where the physician makes use of a direct line of sight
into the patient because some of the electrodes may be located
behind the anatomical structure.
[0123] An electrode identification system in accordance with a
present invention may be provided to enable the physician to
readily determine how many of the electrodes are located outside of
an outer member. The identification system, one embodiment of which
is illustrated in FIG. 18, includes indicia associated with the
electrodes and corresponding indicia on the outer member. More
specifically, the illustrated embodiment includes unique indicia
(i.e. the indicia that are visually distinguishable from one
another) 130a, 132a and 134a on the distal member 18, each of which
corresponds to a particular one of the proximal-most three of the
seven electrodes 20, and corresponding indicia 130b, 132b and 134b
on the distal portion of the outer member 22. The exemplary indicia
is in the form of colored rings or bands. Indicia 130a and 130b are
black, indicia 132a and 132b are red, and indicia 134a and 134b are
blue. The order of the indicia (i.e. black, red, blue) is the same
on the distal member 18 and outer member 22.
[0124] The indicia is used by the physician in the following
manner. When a loop is formed around pulmonary veins in the manner
illustrated in FIG. 5, a number of electrodes 20 will be located
behind the pulmonary veins (from the physicians perspective) and
one of the electrodes will be located immediately adjacent the
distal end of the outer member 22. If, for example, the indicia
associated with the electrode 20 adjacent the distal end of the
outer member 22 is the blue indicia 134a, the physician will know
by reviewing the indicia on the distal end of the outer member that
there are two electrodes proximal to the "blue" electrode (i.e. the
electrode associated with the red indicia 132b and the electrode
associated with the black indicia 130b). Given the fact that two of
the electrodes 20 are located within the outer member 22, the
physician will be able to determine that the distal-most five
electrodes are in contact with tissue, despite the fact that one or
more of the five electrodes is not visible by direct observation
because they are behind the pulmonary veins.
[0125] The number of electrodes that have indicia associated
therewith, as well as the percentage of the total number electrodes
that have indicia associated therewith, will depend on the
particular surgical procedure for which the identification system
is intended. Other visible indicia, such as alpha-numeric symbols
or shading, may also be employed. Additionally, although the
embodiment of the system illustrated in FIG. 18 is shown in
combination with the surgical device illustrated in FIGS. 1A and
1B, other devices, such as those disclosed in the present
specification, may also be provided with such a system.
[0126] VI. Masking
[0127] The portion of an operative element that is not intended to
contact tissue (or be exposed to the blood pool) may be masked
through a variety of techniques with a material that is preferably
electrically and thermally insulating. This prevents the
transmission of coagulation energy directly into the blood pool and
directs the energy directly toward and into the tissue. This also
prevents collateral damage to tissue by blocking transmission of
coagulation energy into adjacent, non-target tissue. In the context
of epicardial lesion creation, such non-target tissue may include
the phrenic nerve and lung tissue.
[0128] For example, a layer of UV adhesive (or another adhesive)
may be painted on preselected portions of the electrodes to
insulate the portions of the electrodes not intended to contact
tissue. Deposition techniques may also be implemented to position a
conductive surface only on those portions of the assembly intended
to contact tissue. A coating may also be formed by dipping the
electrodes in PTFE material.
[0129] Alternatively, a mask element may be positioned over a
structure that supports one or more electrodes or other operative
element to electrically and thermally insulate the desired portions
thereof. As illustrated for example in FIGS. 19 and 20, a mask
element 136 in accordance with one embodiment of a present
invention includes a main body 138, having a side wall 140 defining
an interior bore 142 and a plurality of openings 144, and a
plurality of fluid retention elements 146 located in the openings.
The main body 138 is preferably formed from material that is
electrically and thermally insulating. The fluid retention elements
146 may be used to retain a conductive liquid such as saline and
release the liquid during diagnostic or therapeutic procedures.
When, for example, the mask element 136 is placed over the
exemplary distal member 18, coagulation energy from the electrodes
20 will only be transmitted through the openings 144.
[0130] With respect to materials, the main body 138 is preferably
formed from an elastic material that will hold the mask element 136
on the distal member 18 or other operative element supporting
structure, yet also allow the surgeon to rotate the main body to
focus the coagulation energy, or remove the mask element
altogether, as desired. A suitable elastic material is silicone
rubber having a thickness that ranges from about 0.05 mm to about 1
mm, depending on the desired level of insulation. For some surgical
devices, the main body 138 need only be bendable, as opposed to
elastic. Here, biocompatible plastics that are commonly used in
catheters, such as Pebaxe.RTM. material and polyurethane, may be
employed and the main body 138 secured to the surgical device with
an adhesive.
[0131] Suitable materials for the fluid retention elements 146
include biocompatible fabrics commonly used for vascular patches
(such as woven Dacron.RTM.), open cell foam materials, hydrogels,
macroporous balloon materials (with very slow fluid delivery to the
surface), and hydrophilic microporous materials. The effective
electrical resistivity of the fluid retention elements 146 when
wetted with 0.9% saline (normal saline) should range from about 1
.OMEGA.-cm to about 2000 .OMEGA.-cm.
[0132] Because it is important that the physician be able to
identify the electrodes 20 or other operative elements that are in
contact with tissue, the exemplary main body 138 should either be
transparent or be provided with indicia (not shown) that allows the
physician to distinguish between the electrodes. Such indicia,
which may be printed directly onto the main body 138 with
biocompatible ink, includes color coding, alpha-numeric indicia and
shading.
[0133] Mask elements in accordance with the present invention may
be used in conjunction with devices other that the shaft and spaced
closed coil electrode structure illustrated in FIG. 20. For
example, the closed coil electrodes may be replaced with open coil
electrodes or a straight piece of wire. Also, temperature sensors
may be moved from the underlying support structure to a portion of
the mask element, preferably to the fluid retention elements. The
temperature sensors could be woven into fabric fluid retention
material or embedded in fluid retention elements formed from other
materials. Here, however, rotational movement of the mask element
should be limited to, for example, 180 degrees in order to prevent
damage to the signal wires that will be connected to the
temperature sensors.
[0134] VlI. Clamp Devices
[0135] As illustrated for example in FIGS. 21-24, a clamp device
148 in accordance with a preferred embodiment of a present
invention includes a forceps-like apparatus 150 and a tissue
coagulation apparatus 152. The forceps-like apparatus 150 includes
arms 154 and 156 that are pivotably secured to one another by a pin
158 to allow the device to be opened and closed. The proximal
portions of the arms 154 and 156 may be formed from rigid or
malleable material. The arm distal portions 160 and 162, which are
curved and support the tissue coagulation apparatus 152, are
preferably formed from malleable material. This allows the arm
distal portions 160 and 162 to be re-shaped by the physician as
needed for particular procedures and body structures (note the dash
lines in FIG. 21). Alternatively, one or both of the arm distal
portions 160 and 162 may be formed from rigid material. The arm
distal portions 160 and 162 and, preferably the entire forceps-like
apparatus 150, will be coated with a layer of insulating material
(not shown), such as heat shrink Pebax.RTM.) material, polyester,
or polyurethane. A pair of handles 164 and 166 are mounted on the
proximal ends of the arms 154 and 156.
[0136] The exemplary tissue coagulation apparatus 152 includes an
operative element support member 168 that may be formed from a
soft, flexible, insulative, biocompatible thermoplastic material
such as Pebax.RTM. material, polyethylene, or polyurethane. In the
illustrated embodiment, which may be used to form lesions around
one or more pulmonary veins, the operative element support member
168 will preferably be about 5 French to about 9 French in
diameter.
[0137] Referring more specifically to FIG. 21, the operative
element support member 168 is a continuous structure, but for the
break at the distal end of the arm distal portions 160 and 162 that
allows the device to be opened and closed, which will form a
continuous loop around a body structure when the clamp device is in
the closed position illustrated in FIG. 21. As such, the electrodes
20 (or other operative element) supported thereon may be used to
create a continuous lesion pattern in tissue when coagulation
energy is applied simultaneously to the electrodes. Additionally,
the curvature of the arm distal portions 160 and 162 and operative
element support member 168 allow the physician to apply pressure to
a body structure, such as a pulmonary vein, that is adequate to
enable the formation of a single continuous transmural lesion all
the way around the body structure in one step without collapsing
the body structure, as would be the case with a device having
straight arm distal portions. The open region defined by the arm
distal portions 160 and 162 and operative element support member
168 may be substantially circular, oval or any other closed shaped
necessary for a particular procedure.
[0138] The operative element support member 168 is preferably
mounted off center by an angle .theta. on the arm distal portions
160 and 162, as best seen in FIG. 24. In the illustrated
embodiment, the operative element support member 168 is
approximately 45 degrees off center. Such positioning provides a
number of advantages. For example, the off center positioning
focuses the coagulation energy downwardly (towards the heart) and
inwardly (towards the pulmonary veins) when the tissue coagulation
apparatus 152 is positioned around one or more pulmonary veins. So
positioned, with side A advanced against heart tissue, the
insulated arm distal portions 160 and 162 act as a shield to
prevent the coagulation of tissue other than that targeted for
coagulation. Moreover, the physicians view of the tissue in contact
with the tissue coagulation apparatus 152 will not be blocked by
the arm distal portions 160 and 162.
[0139] As illustrated for example in FIGS. 21-23, an electrical
conduit 170 connects the tissue coagulation apparatus 152 to an
electrical connector 172 that may be connected to a source of RF
coagulation energy. More specifically, signal wires 41 and 42 from
the electrodes and temperature sensors on the tissue coagulation
apparatus 152 run through the electrical conduit 170 along the arm
156 to the electrical connector 172.
[0140] Another exemplary clamp device, which is generally
represented by reference numeral 174, is illustrated in FIG. 25.
Like the exemplary clamp device illustrated in FIGS. 21-24, clamp
device 174 includes a forceps-like device 176 and a tissue
coagulation apparatus 178 which, unless otherwise indicated, are
essentially the same as the forceps-like device and tissue
coagulation apparatus illustrated in FIGS. 21-24. Here, however,
the proximal ends of the arms 180 and 182 are pivotably secured to
one another by a pin 184 and the handles 186 and 188 are located
just proximally of the pin. Also, given the distance that the
curved arm distal portions 190 and 192 are capable of moving from
one another, the tissue coagulation apparatus 178 includes a pair
of operative element support members 194 and 196 that are connected
to the connector 172 by a pair of electrical conduits 198 and
200.
[0141] It should also be noted that the although the exemplary
clamp devices illustrated above employ a forceps-like apparatus
having a pair of arms connected by a pivot pin to position the
tissue coagulation apparatus around tissue, other apparatus may
also be employed. For example, an elongate apparatus including a
scissors-like handle at one end, curved distal portions at the
other end, and a suitable mechanical linkage joining the two may be
employed.
[0142] VIII. Methods
[0143] In accordance with an invention herein, surgical devices
such as those describe above may be used to support an operative
element on the outer surfaces of body structures for diagnostic
and/or therapeutic purposes. In the context of the treatment of
atrial fibrillation, for example, surgical devices with loop
structures such as those described above may be used to support an
operative element, such as a plurality of spaced electrodes, that
creates transmural epicardial lesions to isolate the sources of
focal (or ectopic) atrial fibrillation.
[0144] Turning to FIG. 26, an exemplary method of treating focal
atrial fibrillation with a device such as that illustrated in FIG.
5 involves the creation of transmural lesions around the pulmonary
veins. Lesions may be created around the pulmonary veins
individually or, as is illustrated in FIG. 26, a first transmural
epicardial lesion 202 may be created around the right pulmonary
vein pair RPV and a second transmural epicardial lesion 204 may be
created around the left pulmonary vein pair LPV. Thereafter, if
needed, a linear transmural epicardial lesion 206 may be created
between the right and left pulmonary vein pairs RPV and LPV. A
linear transmural lesion (not shown) that extends from the
epicardial lesion 204 to the left atrial appendage may also be
formed. The linear lesions may be formed with the probe described
above with reference to FIGS. 17A and 17C. Other suitable surgical
devices for creating linear lesions, one example of which would be
the device illustrated in FIGS. 14-16 without the pull wire, are
disclosed in aforementioned U.S. application Ser. No.
09/072,872.
[0145] Alternatively, as illustrated in FIG. 27, a single lesion
208 may be formed around all four of the pulmonary vein pairs RPV
and LPV.
[0146] Access to the heart may be obtained via a thoracotomy,
thoracostomy or median sternotomy. Ports may also be provided for
cameras and other instruments.
[0147] Surgical devices with loop structures such as those
described above may also be used to create transmural epicardial
lesions in a maze pattern that controls electrical propagation
within the left and right atria. More specifically, a maze pattern
may be created by positioning a plurality of spaced electrodes, or
other operative element, within the pericardial space around the
exterior of the heart at the various locations needed to form the
desired lesion pattern.
[0148] The surgical devices described above may also be urged
through tissue planes (i.e. the space between fascia material and a
particular organ) to properly position the device prior to the
actuation of the operative elements. Such a procedure is referred
to as blunt dissection.
[0149] The clamp devices illustrated in FIGS. 21-25 may also be
used to form lesions such as pulmonary vein lesions 202, 204 and
208, or lesions around other body structures.
[0150] Although the present inventions have been described in terms
of the preferred embodiments above, numerous modifications and/or
additions to the above-described preferred embodiments would be
readily apparent to one skilled in the art. It is intended that the
scope of the present inventions extend to all such modifications
and/or additions and that the scope of the present inventions is
limited solely by the claims set forth below.
* * * * *