U.S. patent application number 12/815093 was filed with the patent office on 2010-10-14 for compound bipolar ablation device and method.
Invention is credited to Roderick E. Briscoe, David E. Francischelli, David J.S. Kim, Alison Lutterman, Paul T. Rothstein.
Application Number | 20100262132 12/815093 |
Document ID | / |
Family ID | 34971586 |
Filed Date | 2010-10-14 |
United States Patent
Application |
20100262132 |
Kind Code |
A1 |
Rothstein; Paul T. ; et
al. |
October 14, 2010 |
Compound Bipolar Ablation Device and Method
Abstract
Method and apparatus for ablating target tissue adjacent
pulmonary veins of a patient. The ablation device can include a
lower jaw assembly including a proximal jaw having a proximal
electrode and a distal jaw having a distal electrode, and an upper
jaw assembly including an upper jaw having an upper electrode. A
proximal actuator can be movable between a first position in which
the proximal jaw is open and a second position in which the
proximal jaw is clamped with respect to the upper jaw. A distal
actuator can be movable between a third position in which the
distal jaw is open and a fourth position in which the distal jaw is
clamped with respect to the upper jaw.
Inventors: |
Rothstein; Paul T.; (Elk
River, MN) ; Briscoe; Roderick E.; (Rogers, MN)
; Francischelli; David E.; (Brooklyn Park, MN) ;
Kim; David J.S.; (Maple Grove, MN) ; Lutterman;
Alison; (Brooklyn Park, MN) |
Correspondence
Address: |
Jeffrey J. Hohenshell;Medtronic, Inc.
710 Medtronic Parkway
Minneapolis
MN
55432
US
|
Family ID: |
34971586 |
Appl. No.: |
12/815093 |
Filed: |
June 14, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11143400 |
Jun 2, 2005 |
7758580 |
|
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12815093 |
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60576245 |
Jun 2, 2004 |
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Current U.S.
Class: |
606/21 ; 606/28;
606/33; 606/41 |
Current CPC
Class: |
A61B 2018/00363
20130101; A61B 2018/00577 20130101; A61B 2018/00375 20130101; A61B
18/1442 20130101 |
Class at
Publication: |
606/21 ; 606/41;
606/33; 606/28 |
International
Class: |
A61B 18/18 20060101
A61B018/18; A61B 18/04 20060101 A61B018/04; A61B 18/02 20060101
A61B018/02 |
Claims
1.-15. (canceled)
16. A method of ablating target tissue adjacent pulmonary veins of
a patient, the method comprising: inserting a lower jaw assembly
through an incision in the patient; inserting an upper jaw assembly
through the incision; coupling the upper jaw assembly to the lower
jaw assembly; moving at least one of a proximal actuator and a
distal actuator in order to position at least one of a proximal jaw
and a distal jaw with respect to an upper jaw; and providing
ablation energy to at least one of an upper electrode, a proximal
electrode, and a distal electrode.
17. The method of claim 16 and further comprising providing
ablation energy individually to at least one of an upper electrode,
a proximal electrode, and a distal electrode.
18. The method of claim 16 and further comprising providing a
liquid to at least one of an upper electrode, a proximal electrode,
and a distal electrode.
19. The method of claim 16 and further comprising coupling the
upper jaw assembly to the lower jaw assembly with at least one of a
magnet and a cable.
20. The method of claim 16 and further comprising moving at least
one of the proximal actuator and the distal actuator perpendicular
to an arm of at least one of the upper jaw assembly and the lower
jaw assembly.
21. The method of claim 16 and further comprising moving at least
one of a trigger, a knob, and a lever to move at least one of the
proximal actuator and the distal actuator.
22. The method of claim 16 and further comprising moving a distal
release button to release distal jaw after performing an
ablation.
23. The method of claim 16 and further comprising providing at
least one of radio frequency energy, thermal energy, cryogenic
energy, and microwave energy.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of the filing date of
U.S. Provisional Patent Application No. 60/576,245 filed on Jun. 2,
2004, which is incorporated herein by reference in its
entirety.
BACKGROUND
[0002] Various types of electrocautery devices are used for
ablating tissue. Typically, such devices include a conductive tip
or blade which serves as one electrode in an electrical circuit
which is completed via a grounding electrode coupled to the
patient. With sufficiently high levels of electrical energy between
the two electrodes, heat is generated which is sufficient to
denature proteins within the tissue and cause cell death.
[0003] By controlling the energy level, the amount of heat
generated and the degree, of tissue damage can also be controlled.
High levels of voltage can actually cut and remove tissue (i.e.,
electrosurgery), while lower levels will simply create sufficient
heat to cause cell damage, but leave the structure intact (i.e.,
catheter ablation) and block electrical pathways within the tissue.
Irrigation of the electrode(s) with saline or other conductive
fluid can decrease the interface impedance, cool the tissue and
allow for a greater lesion depth.
[0004] The treatment of chronic atrial fibrillation (AF) requires
the creation of numerous linear lesions that extend completely
through the thickness of the tissue. Some electrophysiologists have
created these lesions using a tip electrode of standard ablation
catheters. These catheters were designed to create spot lesions,
typically for ablation of specific structures or focal
abnormalities. In order to make the linear lesions required to
replicate the MAZE procedure, an electrophysiologist makes a series
of focal lesions, and "connects the dots."
[0005] Manufacturers have therefore developed catheters that have a
linear array of electrodes along a long axis (i.e., the Amazr,
MECCA, and Revelation catheters). The catheter and electrodes can
be positioned in contact with the tissue and either individually or
sequentially apply energy to each electrode. Additionally,
catheters which incorporate an electrode which is energized and
moves along the length have been proposed.
[0006] Surgeons have also been able to create linear lesions on the
heart using applications of the same techniques. For example,
Kottkamp et al. in an article entitled "Intraoperative
Radiofrequency Ablation of Chronic Atrial Fibrillation: A Left
Atrial Curative Approach by Elimination of Anatomic `Anchor`
Reentrant Circuits," Journal of Cardiovascular Electrophysiology,
1999; .sctn.10:772-780 disclosed using a hand-held device that
creates as series of spot or short (<1 cm) linear lesions. Other
investigators have used long, linear unipolar probes to create
somewhat longer lesions, such as described by Shirmoikd E. et al.
in an article entitled "In Vivo and In Vitro Study of
Radio-Frequency Application with a New Long Linear Probe:
Implication for the MAZE Procedure," Journal of Thoracic and
Cardiovascular Surgery, 2000; .sctn.120:164-72. Still others have
used multi-electrode linear catheters, similar to those described
above to create a series of ablations that net a linear lesion, as
described by Melo J. et al. in an article entitled "Endocardial and
Epicardial Radiofrequency Ablation in the Treatment of Atrial
Fibrillation with a New Intra-Operative Device," European Journal
of Cardio-Thoracic Surgery; 2000; .sctn.18:182-186.
[0007] U.S. patent application Ser. No. 10/015,690, in the names of
Francisichelli et al. describes a bipolar ablation device that
integrates an electrode into jaws of a hemostat-like or
forceps-like device, known as the Cardioblate-BP. This results in a
tool that can clamp and ablate the tissue in between the jaws. In
conjunction with a transmurality algorithm, this configuration is
amenable to creating transmural lesions. However, the
Cardioblate-BP was designed to access the heart via a mid-line
sternotomy. In order for the therapy to be considered as
stand-alone, access must be made less invasively. Simply placing
the Cardioblate-BP jaw onto an endoscopic handle has certain
advantages, but there are significant limitations when trying to
manipulate both jaws simultaneously through separate tissue
spaces.
[0008] A microwave device that can loop around the posterior of the
heart to encircle the pulmonary veins has been developed. A right
thorocotomy is created at about the fourth intercostal space, and
the pericardium is freed behind the superior vena cava and the
inferior vena cava. A moveable antenna slides within an integral
sheath and discrete sections are ablated in series is described by
Saltman, "AE in a Completely Endoscopic Approach to Microwave
Ablation for Atrial Fibrillation," Heart Surgery Forum, 2003,
6(3):E38-E41.
[0009] Today, the MAZE procedure is performed with traditional cut
and sew techniques. The market is demanding quicker, safer and less
invasive approaches. Many companies are developing ablation
techniques that heat (or cool) and thermally destroy the underlying
tissue. Methods of chemical ablation have also been proposed.
SUMMARY OF THE INVENTION
[0010] Accordingly, there is a need for a method and device that
results in less trauma to the patient, fewer insertions and
removals of the ablation tools, and more flexibility for selecting
ablation configurations using a single tool to ablate target tissue
of a patient's heart. A need also exists for a compound bipolar
ablation device for minimally-invasive isolation of the pulmonary
veins without completely occlude blood flow.
[0011] Some embodiments of the invention provide an ablation device
for ablating target tissue adjacent pulmonary veins of a patient.
The ablation device can include a lower jaw assembly including a
proximal jaw having a proximal electrode and a distal jaw having a
distal electrode, and an upper jaw assembly including an upper jaw
having an upper electrode. A proximal actuator can be movable
between a first position in which the proximal jaw is open and a
second position in which the proximal jaw is clamped with respect
to the upper jaw. A distal actuator can be movable between a third
position in which the distal jaw is open and a fourth position in
which the distal jaw is clamped with respect to the upper jaw.
[0012] Embodiments of a method of the invention can include
inserting a lower jaw assembly through an incision in the patient
and inserting an upper jaw assembly through the incision. The
method can include coupling the upper jaw assembly to the lower jaw
assembly. The method can also include moving at least one of a
proximal actuator and a distal actuator in order to position at
least one of a proximal jaw and a distal jaw with respect to an
upper jaw and providing ablation energy to at least one of an upper
electrode, a proximal electrode, and a distal electrode.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a posterior cross-sectional view of a patient's
heart and a conventional bipolar ablation device.
[0014] FIG. 2 is a posterior cross-sectional view of a patient's
heart and a schematic representation of a compound bipolar ablation
device according to one embodiment of the invention.
[0015] FIGS. 3, 3A, and 3B are perspective and cross-sectional
views, of a lower jaw assembly of a compound bipolar ablation
device according to one embodiment of the invention.
[0016] FIGS. 4 and 4A are perspective and cross-sectional views of
a compound bipolar ablation device according to one embodiment of
the invention, including the lower jaw assembly of FIG. 3 and an
upper jaw assembly.
[0017] FIG. 5 is a perspective view of the compound bipolar
ablation device of FIG. 4 having a cable clamp in a locking
position.
[0018] FIG. 6 is a perspective view of the compound bipolar
ablation device of FIGS. 4 and 5, including a distal jaw engaged
with an upper electrode.
[0019] FIG. 7 is a perspective view of the compound bipolar
ablation device of FIGS. 4 and 5, including the distal jaw and a
proximal jaw engaged with the upper electrode.
[0020] FIG. 8 is a perspective view of the compound bipolar
ablation device of FIGS. 4 and 5, including the proximal jaw
engaged with the upper electrode.
[0021] FIG. 9 is a perspective view of a compound bipolar ablation
device according to another embodiment of the invention.
[0022] FIGS. 10, 10A, and 10B are perspective views of a compound
bipolar ablation device according to another embodiment of the
invention.
[0023] FIG. 11 is a perspective view of a compound bipolar ablation
device according to another embodiment of the invention.
DETAILED DESCRIPTION
[0024] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limited. The use of "including,"
"comprising" or "having" and variations thereof herein is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items. The terms "mounted," "connected" and
"coupled" are used broadly and encompass both direct and indirect
mounting, connecting and coupling. Further, "connected" and
"coupled" are not restricted to physical or mechanical connections
or couplings, and can include electrical connections or couplings,
whether direct or indirect.
[0025] FIG. 1 is a posterior cross-sectional view of a patient's
heart illustrating atrial tissue 10, pulmonary veins 12, right
pulmonary veins 14, left pulmonary veins 16, and the oblique sinus
18. FIG. 1 also illustrates a conventional bipolar ablation device
including a superior jaw 20 and an inferior jaw 22. When creating
lesions with conventional bipolar clamping-type devices, both jaws
20, 22 (containing electrodes) are manipulated simultaneously
through two separate tissue planes, as shown in FIG. 1. For
example, if a surgeon wants to ablate around the pulmonary veins
12, one jaw 20 would have to be placed behind the superior vena
cava, through the transverse sinus, and over the superior pulmonary
veins. Simultaneously, the other jaw 22 would need to be placed
behind the inferior vena cava, through the oblique sinus 18 and
under the inferior pulmonary veins. This is further complicated by
the relatively fixed angle at a hinge joint of the clamping device.
As a result, a surgeon has difficulty in simultaneously advancing
both jaws 20, 22 into two separate tissue spaces. Although the
superior jaw 20 can be manipulated into the transverse sinus, the
inferior jaw 22 is hindered from the oblique sinus 18 by the right
inferior pulmonary vein 14.
[0026] FIG. 2 is a posterior cross-sectional view of a patient's
heart and jaws 24, 26 placed independently into two separate spaces
according to one embodiment of the invention. After positioning,
both jaws 24, 26 can be joined at a hinge point. This is a less
invasive approach, resulting in less trauma to the patient than
during a sternotomy. Some embodiments of the invention provide a
bipolar ablation device that can produce a narrower lesion than a
monopolar. A bipolar ablation device according to some embodiments
of the invention can create a long continuous lesion with two
separate ablations, without completely occluding blood flow
(resulting in less trauma than complete occlusion of the pulmonary
veins 12).
[0027] Some embodiments of the invention provide an ablation device
having separable compound jaws for clamping to apply energy, such
as radio frequency energy, to ablate tissue in the heart of a
patient suffering from atrial fibrillation. After appropriate
dissection, the separable jaws can be placed in the thoracic cavity
through an incision. This can be through a thorocotomy, sub-xyphoid
incision, stemotomy, or other suitable incisions. Ports may be used
to aid insertion, and a positioning device, such as a Starfish
positioning device manufactured by Medtronic, Inc., may also be
used to lift, rotate, or elevate the heart.
[0028] As shown schematically in FIG. 2, using a small incision in
the patient's chest, an ablation device 30 can be inserted
piecemeal into a position in the patient's chest. The pieces (e.g.,
jaws 24, 26) can be assembled and manipulated to bring electrodes
into contact with a patient's beating heart. Selecting the
appropriate configuration of the compound jaws 24, 26 to engage and
ablate tissue in the heart, the surgeon can perform the ablation
procedure quickly without removal, manipulation, or substitution
and reinsertion of the ablation device 30. Some embodiments of the
invention provide a clamping ablation device 30 with independent
separable jaws 24, 26. Each jaw 24, 26 can be individually
manipulated into the appropriate space. Once positioned, the jaws
24, 26 can be brought together to create a bipolar system.
[0029] Embodiments of the invention can results in a patient
experiencing less trauma because of the minimal invasiveness of
delivering the working bipolar ablators to the heart tissue to be
treated. Blood contacting devices, such as catheters, may not be
used so that the use of biomaterials may not be required.
[0030] Embodiments of the invention can allow the surgeon to make
narrow, linear ablation lesions quickly to reduce the time the
patient is in the procedure. The surgeon can create the lesions
deeply in the tissue of the heart while minimizing the damage to
surrounding tissue. The creation of a long lesion can be achieved
by making contiguous lesions using the ablation device 30. The
compound jaws 24, 26 can allow the surgeon to selectively make a
lesion using a proximal electrode set, a distal electrode set, or
both sets simultaneously, depending on the conditions.
[0031] Embodiments of the invention can be adapted to maneuver
around tissue that should be protected and minimize removal and
reinsertion of different types of ablation devices to quickly
achieve the desired ablation of the patient's heart tissue. One
embodiment of the invention can be a configurable configuration
that can allow the ablation device 30 to be used as a bipolar clamp
for creating ablative lesions in three different configurations
without removal from the patient's chest.
[0032] In general, the bipolar ablation device 30 can minimize the
invasive nature of the procedure of ablating tissue in the
patient's heart. The method and apparatus of the invention can
result in less trauma to the patient and less chance of
accidentally damaging the heart and surrounding structures.
Embodiments of the invention can minimize trauma to the patient by
minimizing the size of the incision required to insert the ablation
device 30 through the patient's chest wall. Embodiments of the
invention can also minimize the trauma to the patient by making
more precise ablations and minimizing unnecessary tissue
destruction. Embodiments of the invention can use bipolar ablation
which results in narrower lesions and less atrial debulking than
traditional monopolar ablation approaches. Embodiments of the
invention can also reduce the trauma on the patient by making the
procedure achieve its objectives in a shorter time. This is done by
allowing the surgeon to create linear lesions in the heart from the
epicardial surface of the beating heart.
[0033] In some embodiments, a bipolar ablation device 30 in which a
grounding electrode is in close proximity to a conductive tip) can
create narrower and deeper lesions. The grounding electrode can be
approximately the same dimension as the conductive tip, and both
electrodes can be used to create the lesion.
[0034] Embodiments of the bipolar ablation device 30 can be
designed to be used in a minimally-invasive environment (e.g., a
mini-thoracotomy or an endoscopic procedure). The ablation device
30 can clamp atrial tissue in a two-step process in order to
minimize the time of complete blood flow occlusion while ensuring a
continuous lesion. Some embodiments of the invention can use
magnets in order to latch two handle halves together in a secure
and predetermined orientation. Other embodiments of the invention
can use a single cable routed through two separate small jaws,
looped around a larger jaw, and then locked to the larger jaw in
order to actuate the smaller jaws individually. Once both jaws 24,
26 are appropriately positioned, they can be brought together at a
hinge point and along an operating shaft to be assembled.
Embodiments of the invention can use magnets, keys, accessory
tools, and/or visualization techniques to quickly and securely
assemble the pieces in a predetermined relation to each other.
After assembly, the jaws 24, 26 may be opened and closed to act as
a bipolar ablation device. Removal from the patient after ablation
can be done as an assembled unit or after disassembly. In one
embodiment, to align the jaws, magnets can be positioned in a hinge
area. The operating shaft can be steerable to facilitate insertion
and blunt dissection. An appropriate transmurality algorithm may be
used to indicate a complete lesion to the surgeon or to terminate
power when a lesion is completed. Some embodiments of the ablation
device 30 can be inserted from a thorocotomy to simultaneously
ablate all the pulmonary veins 12, or the access can be from
another incision, such as sub-xyphoid incision. Alternatively, the
pulmonary veins 12 may be isolated singularly, in pairs, or in any
suitable combination.
[0035] The ablation device 30 can be designed to isolate the
pulmonary veins 12 for ablating, in some embodiments, the left
pulmonary veins 16 separately, from the right pulmonary veins 14.
The ablation device 30 can include lower jaw assembly 32 and an
upper jaw assembly 90. As shown in FIG. 3, the lower jaw assembly
32 can include an elongated arm 34 with a handle 36 on a proximal
end 38 of the ablation device 30 and two separate pivoting jaws 42,
62 on the distal end 40 of the ablation device 30.
[0036] The arm 34 can include a spring-loaded proximal hinge 48
pivotally connecting a proximal jaw 42 to the handle 36. The
proximal jaw 42 can include a proximal spring in the proximal hinge
48 for bearing against and maintaining the proximal jaw 42 in an
open position. A proximal electrode 50 can be mounted on the
proximal jaw 42 for transferring ablation energy to atrial tissue
10. As shown, in FIG. 3A, the proximal electrode 50 can include a
cover 51 to prevent direct contact with the atrial tissue 10. A
supply tube 52 can be in fluid communication with a chamber 58
formed by the cover 51. A proximal supply tube 74 can extend from
the handle 36 to a fluid supply 122 (as shown in FIG. 6). A
conductor 56 can be mounted on the arm 34 and connected to the
proximal electrode 50. The conductor 56 can extend along the lower
jaw assembly 32 and can, extend from the handle 36 to an ablation
energy source 120 (as shown in FIG. 6).
[0037] As shown in FIG. 3, adjacent a distal end 40 of the lower
jaw assembly 32, a distal jaw 62 can be connected to the arm 34 by
a spring-loaded distal hinge 68 to maintain the distal jaw 62 in an
open position. The distal jaw 62 can include a distal electrode 70
with a distal cover 72 surrounding the distal electrode 70 to form
a chamber 73, as shown in FIG. 3B. A distal supply tube 74 can be
positioned on the arm 34 and can be in fluid communication with the
chamber 73. The distal supply tube 74 can extend along the lower
jaw assembly 32 from the handle 36 to a fluid supply 122 (as shown
in FIG. 6). A conductor 78 can be mounted on the arm 34 and can be
connected to the distal electrode 70. The conductor 78 can extend
along the lower jaw assembly 32 from the handle 36 to an ablation
energy source 120 (as shown in FIG. 6).
[0038] As shown in FIG. 3, the handle 36 can include guides 82 and
magnets 83 for assembly and alignment with the upper jaw assembly
90 (as shown in FIG. 4). A proximal jaw actuator 54 can be mounted
on the proximal end 36 near the handle 36 and can be connected to
the proximal jaw 42 through the proximal jaw hinge 48. The proximal
jaw actuator 584 can bear against the spring-loaded proximal jaw
hinge 48 to overcome the force holding the proximal jaw 42 in the
open position and move the proximal electrode 50 into a tissue
engagement position.
[0039] A distal jaw actuator 76 can be connected to the distal jaw
62 through the distal jaw hinge 68. The distal jaw actuator 76 can
bear against the spring-loaded distal jaw hinge 68 to overcome the
spring force and move the distal electrode 70 into a tissue
engagement position. As shown in FIG. 3, the distal actuator 76 and
the proximal actuator 54 can be connected to a cable loop 85, and
can be actuation levers, in one embodiment. Both jaws 42, 62 can be
spring-loaded in an open position. The jaws 42, 62 can include
electrodes 50, 70. The distal and proximal actuators 54, 76 can be
attached to a sliding block (not shown) that can slide parallel to
the arm 34. One end of the cable 85 can be attached to the distal
actuator 76. The cable 85 can extend along the length of the arm 34
and into the distal jaw 62. The cable 85 can form a loop outside
the lower jaw assembly 32 and can then extend into the proximal jaw
42. The cable 85 can then extend back down the arm 34 and can
attach to the proximal actuator 54. In other embodiments, the cable
85 can be actuated by a method other than a lever, such as thumb
slide, a knob, etc.
[0040] After proper dissection, the lower jaw assembly 32 can be
placed through an incision or port into the right side of the
patient's chest. The lower jaw assembly 32 can be guided into the
oblique sinus 18 (as shown in FIG. 2) until the electrodes 50, 70
are positioned around the pulmonary veins 12.
[0041] As shown in FIG. 4, the upper jaw assembly 90 can include a
handle 92 and an upper arm 96. An upper electrode 98 can be mounted
on the upper arm 96 at the distal end 40 of the ablation device 30.
The upper arm 96 can be attached to the lower jaw assembly 32 by
threading the upper electrode 98 and the adjacent portion of the
upper arm 96 through the loop of the cable 85. The handle 92 can
include receiving ports for the guides 82 (as shown in FIG. 3) on
the handle 36 of the lower jaw assembly 32. A cable slot 97 can be
positioned on the upper arm 96 adjacent the upper electrode 98. A
conductor 95 can extend from the upper electrode 98 along the upper
arm 96 through the handle 92 to the ablation energy source 120 (as
shown in FIG. 6). When properly aligned, the handle 36 and the
handle 92 can mate with each other, and the loop of the cable 85
can be secured around the upper arm 96 at the cable slot 97 to form
an arm clamp 99.
[0042] As shown in FIG. 4A, the upper electrode 98 can include a
cover 100 that can form a chamber 101. An upper supply tube 102 can
be in fluid communication with the chamber 101. The upper supply
tube 102 can extend through the upper arm 96 from the handle 92 to
the liquid source 122 (as shown in FIG. 6).
[0043] The handles 36, 92 of the upper jaw assembly 32 and lower
jaw assembly 90 can include one or more magnets 83 that can hold
the handles 36, 92 together. The cable 85 can be attached to the
arm clamp 99 at the distal end 40 and a clamp actuator 106 at the
proximal end 38 of the ablation device 30. The upper electrode 98
can be a single long electrode approximately the same length as the
sum of the lengths of the distal electrode 70 and proximal
electrode 50. The upper electrode 98 can be aligned with the distal
electrode 70 and proximal electrode 50 to form a single bipolar
ablating device 108. In some embodiments, the bipolar ablating
device 108 can perform ablations in three configurations--upper
electrode 98 and distal electrode 70; upper electrode 98 and
proximal electrode 50; or upper electrode 98, distal electrode 70,
and proximal 50 electrode.
[0044] In one embodiment, a distal end of the proximal electrode 50
can be adjacent to a proximal end of the distal electrode 70 on the
upper jaw assembly 32. The electrodes 50, 70, 98 can be formed in a
particular shape with respect the geometries of the tissue being
ablated. The patient's size and age can determine the shape of the
electrodes 50, 70, 98.
[0045] As shown in FIG. 5, pulling back on the distal and proximal
actuation levers 54, 76 together can tighten the loop of the cable
85 so that it can drop into the cable slot 97. Turning the clamp
actuator 106 can lock the cable 85 to the upper jaw 94.
[0046] FIG. 6 is a bottom perspective view of the ablating device
30. The operation of the distal actuator 70 is shown pulling the
distal electrode 70 toward the upper electrode 98 for clamping the
atrial tissue 10 around the left pulmonary veins 16. The proximal
jaw 42 can be positioned over the right pulmonary veins 14 allowing
some blood flow through the pulmonary veins 12. A ratcheting
mechanism 112 can be used to lock the distal actuator 76 in various
positions to accommodate different tissue thickness. After ensuring
proper placement, the distal electrode 70 can be actuated and the
ablation can be performed. The ablating power supply 120 can be
connected to the conductors 56, 78, 95 to provide independently
controllable energy to each electrode 50, 70, 98, depending on when
energization is needed to ablate the atrial tissue 10. The liquid
source 122 can be in fluid communication with the chambers 58, 73,
101 of the electrodes 50, 70, 98. A saline liquid can be forced
into the chambers 58, 73, 101 to flow through pores in the covers
51, 72, 100. The covers 51, 72, 100' can be constructed of a porous
polymer material from a supplier such as Porex Porous Products
Group, 500 Bohannon Rd., Fairburn, Ga. 30213-2828. The liquid
source 122 can pump a saline or other suitable liquid into the
chambers 58, 73, 101 for conducting the ablation energy (such as
radio frequency energy) through the covers 51, 72, 100 and into the
atrial tissue 10 between the upper electrode 98 and one or both of
the proximal electrode 50 and the distal electrode 70.
[0047] The proximal actuator 54 can also be rotated to pull the
proximal electrode 50 toward the upper electrode 98 in a tissue
engagement position that will completely occlude blood flow through
the pulmonary veins 12. Use of the proximal electrode 50 can ensure
alignment and continuity along the length of the lesion.
[0048] As quickly as possible to minimize the time of complete
occlusion, a distal release button 80 (as shown in FIG. 6) can be
actuated to allow the distal actuator 76 and the electrode 70 to be
released and the spring-loaded hinge 68 to move the distal
electrode 70 into an open position. The proximal electrode 50 can
then be the only electrode in contact with the atrial tissue 10.
After ensuring proper placement, the proximal electrode 50 can be
activated and the ablation can be performed.
[0049] Once the ablation is complete, a proximal release button
(not shown) can be actuated to release the proximal electrode 50
from its tissue engagement position and allow the spring-loaded
hinge 48 to move the proximal electrode 50 into an open position.
The clamp 99 can be released to unlock the cable 85 and allow the
upper assembly 90 to be separated from the lower jaw assembly
32.
[0050] In operation, the lower jaw assembly 32 can be inserted into
the patient through an incision to bring the proximal and distal
electrodes 50, 70 into contact with the right and left pulmonary
veins 14, 16. The upper jaw assembly 90 can be inserted through the
incision or port and guided first through the loop of the cable 85,
then through the transverse sinus until the magnets 83 on the
handles 36, 92 line up with their corresponding guides 82.
[0051] The distal jaw 62 can be used to ablate the atrial tissue
adjacent one pulmonary vein first. The tissue adjacent the
pulmonary veins can be ablated by the distal electrode 70. To
maintain the continuity of the lesion, the proximal jaw 42 can be
moved to the closed position to facilitate alignment with the
previous lesion and the distal jaw 62 can be released into the open
position. The atrial tissue adjacent the other pulmonary veins can
be ablated by energizing the proximal electrode 50.
[0052] FIG. 7 illustrates the proximal actuator 54 and the distal
actuator 76 positioned to clamp both the proximal jaw 42 and the
distal jaw 62 against atrial tissue 10 and/or the upper jaw 94.
FIG. 8 illustrates the distal actuator 76 positioned to release the
distal jaw 62 and the proximal actuator 54 positioned to clamp the
proximal jaw 42.
[0053] As shown in FIG. 9, one embodiment of the ablation device
can be a two-piece bipolar ablation device 130 with separable
electrodes 148, 162. The two-piece ablation device 130 can use a
two-step mechanical process to clamp the atrial tissue 10 around
the pulmonary veins 14, 16. The two-piece ablation device 130 can
be positioned to clamp around one set of pulmonary valves then the
other. The compound ablation device 130 can allow some blood flow
and can be used on a beating heart.
[0054] The ablation device 130 can include a lower jaw 154 and an
upper jaw assembly 132 that can be independent and separable. Each
jaw assembly 132, 154 can be individually manipulated into the
appropriate space. Once positioned, the jaw assemblies 132, 154 can
be brought together to create a bipolar system 140.
[0055] The upper jaw assembly 132 can include an upper arm 134 with
an upper handle (not shown) on a proximal end 138 and an upper-jaw
142 on a distal end 140. A fixed upper jaw hinge 146 or use of a
semi-flexible material that can be positioned on the upper arm 134
between the upper handle (not shown) and the upper jaw 142. An
upper electrode 148 can be mounted on the upper jaw 142 at the
distal end 140. The upper electrode 148 can include a cover (not
shown) and a conductor (not shown). The conductor can be connected
to the upper electrode 148 and can extend along the upper arm 134
from the upper handle (not shown) to an ablation energy source (not
shown). The cover can be positioned over the upper electrode 148 to
form a chamber (not shown). An upper supply tube can extend along
the upper arm 134 from the handle (not shown) to a liquid source
(not shown).
[0056] The lower jaw assembly 154 can include an arm 155 having a
lower jaw 156 and a lower jaw hinge 160. A lower electrode 162 can
be mounted on a distal end 163 of the lower jaw assembly 154. A
cover can be positioned over the lower electrode 162 to form a
chamber (not shown). A lower supply tube (not shown) can be
connected to the chamber and can extend along the lower arm 155
from a lower handle 172 to a liquid source 5. A slider tube 135 can
have a handle 136 that can be pushed toward the distal end 140. As
the slider tube 135 passes over the upper jaw hinge 146 and lower
jaw hinge 160 the upper electrode 148 and lower electrode 162 clamp
together.
[0057] FIGS. 10, 10A, and 10B are additional perspective views of
the ablation device 30 in various positions. FIG. 10 illustrates
the proximal actuator 54 and the distal actuator 76 in first
positions which cause the proximal jaw 42 and the distal jaw 62 to
both be open. In FIG. 10, the cable 85 is loose within the arm
clamp 99. FIG. 10A illustrates the distal actuator 76 in a second
position in which the distal jaw 62 is clamped with respect to the
upper jaw 94, the proximal actuator 54 remaining in the first
position, and the cable 85 tightened within the arm clamp 99. FIG.
10B illustrates the distal actuator 76 back in the first position,
the proximal actuator 54 in the second position in which the
proximal jaw 42 is clamped with respect to the upper jaw 94, and
the cable 85 tightened within the arm clamp 99.
[0058] FIG. 11 is a schematic illustration of the ablation device
30 within a patient's heart. The upper jaw 94 can be positioned
above the superior left and right pulmonary veins 12. The distal
jaw 62 can, be positioned through the oblique sinus 18 and below
the inferior left and right pulmonary veins 12. The proximal jaw 42
can be positioned below the inferior right pulmonary veins 14. The
arms 34 and 96 can extend out of an incision in the patient's
side.
[0059] One embodiment of the invention produces linear radio
frequency lesions in the atria using a hemostat device. However,
embodiments of the invention can also be used with other energy
sources, such as microwave energy, cryogenic energy, thermal
energy, etc. Also, embodiments of the invention can be used for
creating lesions in other tissues such as lung or liver resections.
Additionally, embodiments of the invention can be implemented with
various alignment techniques, such as parallel clamping and
magnetically-aligned electrodes. The invention can provide a method
and embodiments of an ablation device 30 for creating lesions. Such
devices are especially useful for ablating on a beating heart, but
can also be used on a stopped heart (i.e., during cardiopulmonary
bypass).
[0060] Various additional features and advantages of the invention
are set forth in the following claims.
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