U.S. patent application number 12/139912 was filed with the patent office on 2008-12-18 for thermal ablation of biological tissue.
Invention is credited to Steven A. Daniel, David L. Morris.
Application Number | 20080312650 12/139912 |
Document ID | / |
Family ID | 34079316 |
Filed Date | 2008-12-18 |
United States Patent
Application |
20080312650 |
Kind Code |
A1 |
Daniel; Steven A. ; et
al. |
December 18, 2008 |
Thermal Ablation of Biological Tissue
Abstract
An ablation device is described comprising an introducer and an
electrode array. The electrode array couples to a distal end of the
introducer. The electrode array includes a center member having a
distal end configured to penetrate tissue and a plurality of
electrodes. Proximal and distal ends of each electrode are
relatively fixed. The electrodes are dynamically configurable from
a retracted state to a deployed state in which the electrodes form
a relatively spherical shape in a tissue volume.
Inventors: |
Daniel; Steven A.; (Fremont,
CA) ; Morris; David L.; (Lugarno, AU) |
Correspondence
Address: |
COURTNEY STANIFORD & GREGORY LLP
P.O. BOX 9686
SAN JOSE
CA
95157
US
|
Family ID: |
34079316 |
Appl. No.: |
12/139912 |
Filed: |
June 16, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10889756 |
Jul 12, 2004 |
7399299 |
|
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12139912 |
|
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60486874 |
Jul 11, 2003 |
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Current U.S.
Class: |
606/41 |
Current CPC
Class: |
A61B 18/148 20130101;
A61B 2018/00267 20130101 |
Class at
Publication: |
606/41 |
International
Class: |
A61B 18/14 20060101
A61B018/14 |
Claims
1. An ablation device, comprising: an introducer; and an electrode
array coupled to a distal end of the introducer, the electrode
array including a center member having a distal end configured to
penetrate tissue and a plurality of electrodes, wherein proximal
and distal ends of each electrode are relatively fixed, wherein the
plurality of electrodes are dynamically configurable from a
retracted state to a deployed state in which the electrodes form a
relatively spherical shape in a tissue volume.
2-17. (canceled)
Description
RELATED APPLICATION
[0001] This application claims priority from U.S. Patent
Application No. 60/486,874, filed Jul. 11, 2003.
TECHNICAL FIELD
[0002] This invention relates generally to devices and methods for
tissue ablation, and more particularly to the creation of spherical
ablations in biological tissue.
BACKGROUND
[0003] Standard surgical procedures such as tissue resection for
use in treatment of benign and malignant tumors of the liver and
other organs have several key shortcomings affecting efficacy,
morbidity and mortality. A fundamental issue in these shortcomings
is the inability of the resection to be performed in a variety of
cases. To help overcome this limitation a series of mono-polar
radio frequency (RF) devices were designed for use in tissue
ablation and resection. These mono-polar devices however have
limited usefulness in typical clinical settings because they are
overly complex and difficult to use and result in time consuming
procedures that can lead to auxiliary injury to patients through
grounding pad burs. Further, these mono-polar tissue ablation
devices are limited in the scope and size of the ablation that can
be created, and exhibit poor consistency of ablative results along
with an overall low efficiency. Consequently, there is a need for a
tissue ablation system that overcomes the shortcomings of these
mono-polar tissue ablation devices.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a tissue ablation device including a hand piece, a
deployment slider, a delivery member/tube, and a plurality of
energy conduits in a retracted state coupled among an energy source
and a distal tip, under an embodiment.
[0005] FIG. 2 is a tissue ablation device including a hand piece, a
deployment slider, a delivery member/tube, and a plurality of
energy conduits in a deployed state coupled among an energy source
and a distal tip, under the embodiment of FIG. 1.
[0006] FIG. 3 is a distal portion of a tissue ablation device
including a delivery member/tube and a plurality of energy conduits
in a retracted state, under the embodiment of FIG. 1.
[0007] FIG. 4 is a distal portion of a tissue ablation device
including a delivery member/tube and a plurality of energy conduits
in a deployed state, under the embodiment of FIG. 1.
[0008] FIG. 5 shows an enlarged view of the distal portion of a
tissue ablation device including a center deployment rod and a
plurality of energy conduits in a deployed state, under the
embodiment of FIG. 1.
[0009] FIG. 6 shows an enlarged view of the mid-section of a tissue
ablation device including a center deployment rod and a plurality
of energy conduits in a deployed state, under the embodiment of
FIG. 1.
[0010] FIG. 7 shows an exploded view of the distal end of a tissue
ablation device including a center deployment rod along with a
rotated side view of the delivery member/tube including a plurality
of energy conduits and deployment rod, and a distal tip, under the
embodiment of FIG. 1.
[0011] FIG. 8 is an end view of a plurality of deployed energy
conduits having diameters of 5, 6, and 7 centimeters (cm), under
the embodiment of FIG. 1.
[0012] FIG. 9 is a cross-section of an energy conduit configured
for at least one of cutting, separating, and parting tissue as it
is pressed or forced against the tissue, under an embodiment.
[0013] FIG. 10 is a distal portion of a tissue ablation device
including a delivery member/tube and a plurality of energy conduits
in a deployed state, under an alternative embodiment.
[0014] FIG. 11 is a distal portion of a tissue ablation device
including a delivery member/tube and a plurality of energy conduits
in a deployed state, under yet another alternative embodiment.
[0015] FIG. 12 is a flow diagram of tissue ablation procedure using
the tissue ablation device, under an embodiment.
[0016] In the drawings, the same reference numbers identify
identical or substantially similar elements or acts. To easily
identify the discussion of any particular element or act, the most
significant digit or digits in a reference number refer to the
Figure number in which that element is first introduced (e.g.,
element 108 is first introduced and discussed with respect to FIG.
1).
DETAILED DESCRIPTION
[0017] A tissue ablation system including numerous components and
methods is described herein for generating tissue ablation volumes
in various biological tissues. The biological tissue includes
tissue of a variety of organs of the human body including the
liver, spleen, kidney, lung, breast and other organs, but is not so
limited. In the following description, numerous specific details
are introduced to provide a thorough understanding of, and enabling
description for, embodiments of the tissue ablation system. One
skilled in the relevant art, however, will recognize that the
tissue ablation system can be practiced without one or more of the
specific details, or with other components, systems, etc. In other
instances, well-known structures or operations are not shown, or
are not described in detail, to avoid obscuring aspects of the
tissue ablation system.
[0018] FIG. 1 is a tissue ablation system 100, under an embodiment.
The tissue ablation system 100 includes a tissue ablation device
101 coupled to at least one energy source 112. The tissue ablation
device 101 includes a hand piece 102, a deployment slider 104, a
delivery member/tube 106, a plurality of energy conduits 108, and a
distal tip 110, under an embodiment. The energy conduits 108, also
referred to herein as electrodes 108, are in a retracted state, but
are not so limited. FIG. 2 is a tissue ablation device with the
energy conduits 108 in a deployed state, under an embodiment. The
tissue ablation device 101 can also include other components as
known in the art and as appropriate to procedures including the
tissue ablation device 101.
[0019] The components of the tissue ablation system 100 are
described in turn with reference to FIG. 1 and FIG. 2. The hand
piece 102 of the tissue ablation device 101 includes a handle by
which the user grips the tissue ablation device 101. The hand piece
102 provides a coupling between the energy source 112 and one or
more of the energy conduits 108 which may or may not be coupled to
at least one of the hand piece 102 and the energy source 112. The
deployment slider 104 or advancement mechanism 104, which in an
embodiment is integral to the hand piece 102, deploys or retracts
the energy conduits 108 upon actuation.
[0020] The tissue ablation device 101 also includes a delivery
member/tube 106 that supports placement of the energy conduits 108
in the target tissue, but is not so limited. The delivery
member/tube 106 is formed using material that is at least one of
electrically conductive, conditioned, and coated to allow for
electrical conductivity via the electrodes. As an example, the
delivery member/tube 106 is formed using at least one of stainless
steel, nickel titanium, alloys, and plastics including Ultem,
Polycarbonate, and Liquid crystal polymer, but is not so limited.
The delivery member/tube 106 has a diameter approximately in a
range of 0.05 to 0.5 inches, and has a length approximately in a
range of 0.1 to twenty (20) inches as appropriate for extension
into a body region appropriate to the treatment procedure. As one
example, the delivery member/tube 106 of an embodiment has a
diameter of between approximately 0.08 and 0.3 inches and a length
between approximately two (2) and twelve (12) inches.
[0021] The energy conduits 108 while configured appropriately for
insertion into particular tissue types, are formed from one or more
materials and have a shape, size, and pattern that supports
coupling to the target tissue and allows the energy conduits 108 to
deliver sufficient energy to ablate the target tissue. The energy
conduits 108 include materials selected from among conductive or
plated metals and/or plastics, super alloys including shape memory
alloys, and stainless steel, to name a few. The energy conduits 108
comprise nickel titanium alloy, for example, but can be formed from
any number/combination of materials including stainless steel,
nickel titanium, and various alloys.
[0022] The energy conduits 108 of an embodiment, which collectively
may be referred to as an electrode array 108, can have many
different sizes (including lengths and diameters) depending upon
the energy delivery parameters (current, impedance, etc.) of the
corresponding system. The use of energy conduits 108 having
different diameters allows for balancing of energy/energy density
in the target tissue. Therefore, the use of energy conduits 108
having different diameters provides a means of control over energy
balancing in the target tissue in addition to the spacing between
the energy conduits 108. An outside diameter of one or more of the
energy conduits 108 of an embodiment is approximately in the range
of 0.005 to 0.093 inches, but is not so limited. Further, the
energy conduits 108 of an embodiment have lengths sufficient to
generate or create an ablation diameter approximately in the range
of one (1) to fifteen (15) centimeters (cm), but are not so
limited. As one example, the energy conduits 108 of an embodiment
have an outside diameter between approximately 0.01 and 0.025
inches and lengths sufficient to generate or create an ablation
diameter approximately in the range of three (3) to nine (9)
centimeters (cm).
[0023] The energy conduits 108 of various alternative embodiments
can include materials that support bending and/or shaping of the
energy conduits 108. Further, the energy conduits 108 of
alternative embodiments can include non-conducting materials,
coatings, and/or coverings in various segments and/or proportions
along the shaft of the energy conduits 108 as appropriate to the
energy delivery requirements of the corresponding procedure and/or
the type of target tissue
[0024] The energy source 112 of an embodiment (also referred to as
a generator 112 or electrical generator 112) delivers pre-specified
amounts of energy at selectable frequencies in order to ablate
tissue, but is not so limited. The energy source 112 includes at
least one of a variety of energy sources including electrical
generators operating within the radio frequency (RF) range. More
specifically, the energy source 112 includes an RF generator
operating in a frequency range of approximately 375 to 650 kHz and
at a current of approximately 0.1 to 5 Amps and an impedance of
approximately 5 to 100 ohms, but is not so limited. As an example,
the energy source 112 of an embodiment operates at a frequency
approximately in the range of 400 kHz to 550 kHz and at a current
of approximately 0.5 to four (4) Amps, but is not so limited.
Variations in the choice of electrical output parameters from the
energy source 112 to monitor or control the tissue ablation process
may vary widely depending on tissue type, operator experience,
technique, and/or preference.
[0025] The tissue ablation system 100 can include any number of
additional components like, for example, a controller (not shown)
to semi-automatically or automatically control delivery of energy
from the energy source 112. The controller can, for example,
increase the power output to the energy conduits 108, control
temperature when the energy conduits 108 include temperature
sensors or when receiving temperature information from remote
sensors, and/or monitor or control impedance, power, current,
voltage, and/or other output parameters. The functions of the
controller can be integrated with those of the energy source 112,
can be integrated with other components of the tissue ablation
system 100, or can be in the form of stand-alone units coupled
among components of the tissue ablation system 100, but are not so
limited.
[0026] Moreover, the tissue ablation system 100 can include an
operator display (not shown) that provides a display of heating
parameters such as temperature for one or more of the energy
conduits 108, impedance, power, current, timing information, and/or
voltage of the energy source 112 output. The functions of the
display can be integrated with those of the energy source 112, can
be integrated with other components of the tissue ablation system
100, or can be in the form of stand-alone units coupled among
components of the tissue ablation system 100, but are not so
limited.
[0027] In operation a user advances the deployment slider 104 and
in response the energy conduits 108 are forced, or in the case of a
pre-shaped energy conduits released, from the retracted state to
the deployed state. The shape of the deployed energy conduits can,
as shown in FIG. 2, form a series of approximately semi-spherical
segments that, when taken together, form the outline of a sphere.
The tissue ablation device generates a spherical volume of ablated
tissue upon application of energy to the deployed electrodes.
[0028] FIG. 3 is the distal portion of a tissue ablation device 101
including a delivery member/tube 106, a deployment member or rod
112, a plurality of energy conduits 108 in a retracted state (two
energy conduits are shown for simplicity, but the embodiment is not
so limited), and a distal tip 110, under the embodiment of FIG. 1.
The energy conduits 108 are coupled, either individually or
collectively, to an energy source or generator (not shown). When
the energy conduits 108 are in the retracted state, the distal
portion of the tissue ablation device presents a very streamline
profile well suited to piercing tissue and advancement/placement
in/near an area which might contain a malignant or non-malignant
tumor. By piercing the tumor the distal tip can be placed just
beyond the tumor.
[0029] FIG. 4 is the distal portion of a tissue ablation device 101
including a delivery member/tube 106, a deployment member or rod
112, a plurality of energy conduits 108 in a deployed state, and a
distal tip 110, under the embodiment of FIG. 1. The energy conduits
108 are coupled, either individually or collectively, to an energy
source or generator (not shown). Following placement of the distal
portion of the tissue ablation device in the target tissue as
appropriate to the corresponding medical procedure, the user
advances the deployment slider (not shown) to deploy the energy
conduits 108, thus fully encompassing the volume of tissue desired
to be ablated.
[0030] Regarding deploying of the energy conduits 108, some or all
of the energy conduits 108 can be deployed in response to
advancement of the deployment slider. For example, all energy
conduits 108 of an embodiment are deployed simultaneously in
response to advancement of the deployment slider. As another
example, one set of energy conduits 108 can be deployed to form a
sphere having a first diameter while another set of energy conduits
108 can be deployed to form a sphere having a second diameter.
Other alternative embodiments can use additional deployment schemes
known in the art.
[0031] The energy conduits 108 of an embodiment deliver radio
frequency (RF) current to the target tissue and, as such, can be of
alternating electrical polarity. The alternating polarity series of
energy conduits includes various series combinations of alternating
polarities. For example, in an embodiment using ten (10) energy
conduits, the alternating polarity is: positive polarity (+),
negative polarity (-), +, -, +, -, +, -, +, -. An alternative
polarity series is: +, +, -, -, +, +, -, -, +, +. Another
alternative polarity series is: -, -, +, +, -, -, +, +, -, -. Yet
another alternative polarity series is: +, +, +, +, +, -, -, -, -,
-. These examples are exemplary only, and the tissue ablation
system 100 described herein is not limited to ten (10) electrodes
or to these alternating polarity configurations.
[0032] The energy conduits of an alternative embodiment conduct
electricity of a single electrical polarity, with the deployment
rod 112 conducts electricity having an opposite polarity to that of
the energy conduits. In still another alternative embodiment, the
deployable energy conduits are switched between the same electrical
polarity with the deployment rod being the other and alternating
polarity between the deployable energy conduits. In yet another
alternative embodiment, the deployment rod and deployable energy
conduits are of a single electrical polarity and one or more
secondary grounding pads are used therewith to provide an opposite
polarity member.
[0033] Various alternative embodiments can simultaneously use any
number of energy conduits in a procedure in order to form volumes
of ablated tissue having shapes and sizes appropriate to the
treatment procedure. Numerous alternatives would be recognized by
those skilled in the art in view of the tissue ablation device
described herein.
[0034] FIG. 5 shows a distal region or portion of a tissue ablation
device 101 including a center deployment rod 112, a plurality of
energy conduits 108 in a deployed state (two energy conduits are
shown for simplicity, but the embodiment is not so limited),
conduit insulators 504, and a distal tip 110, under the embodiment
of FIG. 1. In support of delivering electrical energy of
alternating polarity via the energy conduits 108, the conduit
insulators 504 mechanically couple the distal ends of the energy
conduits 108 while maintaining electrical insulation between each
of the energy conduits 108. In this tissue ablation device the
deployable energy conduits 108 are coupled to the conduit
insulators 504. The combination of the energy conduits 108 and the
conduit insulators 504 is coupled to a non-electrically conductive
retaining disk 502 that is coupled to an electrically conductive
deployment member 112. Also connected to the deployment member 112
is the electrically conductive distal tip 110 that, in this
embodiment, is suitable for piercing tissue. Advancing the
deployment slider causes the deployable energy conduits or
electrodes 108 to experience a compressive load. As this force
increases beyond the column strength of the deployable energy
conduits 108, the energy conduits 108 buckle and deploy outward in
a controlled fashion.
[0035] Alternatively, the energy conduits 108 can be pre-formed to
a desirable shape when fabricated of a suitable material such as a
nickel titanium alloy. Using the pre-formed electrodes, advancement
of the deployment slider permits the deployable electrodes to
return to their preformed shape. The application of a small amount
of energy such as RF current can help to facilitate the deployment
of the electrodes through the tissue.
[0036] FIG. 6 shows a mid-section of a tissue ablation device 101
including a delivery member/tube 106, a deployment member 112, and
a plurality of energy conduits 108 in a deployed state (two energy
conduits are shown for simplicity, but the embodiment is not so
limited), under the embodiment of FIG. 1. The proximal end 604 of
the energy conduits 108 couples to an electrical insulator 602 or
insulating material 602, but is not so limited.
[0037] FIG. 7 shows an exploded view of a distal region of a tissue
ablation device 101 including a deployment member 112, a distal tip
110, and a rotated side view of an energy conduit retaining disk
502, under the embodiment of FIG. 1. Although a variety of methods
exists to couple the components of the tissue ablation device 101
at the distal end, one such method is a simple screw thread 702
configured to accept a distal end of the deployment member 112.
Alternatively, a press or interference fit between mating parts or
the use of various adhesives can also be used. The retaining disk
502, as described above with reference to FIG. 5, is configured
couple to the deployment member 112 and the distal tip 110.
[0038] FIG. 8 is an end view of a tissue ablation device 101 with
deployed energy conduits 108 forming spheres having diameters of
approximately 5, 6, and 7 centimeters (cm), under the embodiment of
FIG. 1. The tissue ablation device 101 of an embodiment provides
approximately uniform spacing among the energy conduits 108, but
alternative embodiments may support any number/combination of
energy conduit 108 configurations. The tissue ablation device 101
of an embodiment supports a variety of spherical deployment sizes
by providing control over the extent to which the deployable energy
conduits are deployed via the deployment slider, but is not so
limited.
[0039] FIG. 9 is a cross-section of an energy conduit 900
configured for at least one of cutting, separating, and parting
tissue as it is pressed or forced against the tissue, under an
embodiment. The energy conduit 900 is used to form the energy
conduits 108 described above with reference to FIG. 1. As the
energy conduits 900 are advanced from the retracted state (FIG. 3)
to the deployed or expanded state (FIG. 4), the energy conduits 900
penetrate or separate the surrounding tissue. This penetration is
accomplished in one embodiment using energy conduits that have a
geometry suited for separating or cutting the surrounding tissue.
The penetration of tissue by the energy conduits 900 in an
alternative embodiment is accomplished with the application of
energy, for example RF energy, to the energy conduit 900 in order
to facilitate cutting through the tissue during advancement of the
energy conduits. Another alternative embodiment includes the use of
both an energy conduit 900 having a cutting geometry along with the
application of a suitable electrical energy to the energy conduit
900.
[0040] FIG. 10 is a distal portion 1000 of a tissue ablation device
including a delivery member/tube and a plurality of energy conduits
A, B, C, D, E, F, and G (collectively referred to as A-G) in a
deployed state, under an alternative embodiment. The energy
conduits A-G comprise nickel titanium alloy, for example, but can
be formed from any number/combination of materials. Further, the
outside diameter of the energy conduits A-G of an embodiment is
approximately in the range of 0.010 to 0.040 inches, but is not so
limited.
[0041] As described above, the delivery member/tube 1006 provides
sufficient support for placement of the energy conduits A-G.
Advancement of a deployment slider (not shown) advances and deploys
the energy conduits A-G to a deployed shape. The shape of these
energy conduits A-G can form a series of approximately
semi-spherical segments which in this embodiment when taken
together form the outline of a sphere 1099 that fully encompasses a
volume of tissue targeted for ablation. The application of RF
energy to the energy conduits A-G generates or produces a spherical
volume of ablated tissue.
[0042] The energy conduits A-G of an embodiment are configured to
each have an alternating electrical polarity. The energy conduits
of an alternative embodiment are of a single electrical polarity,
with the delivery member/tube 1006 conducting an opposite polarity.
In still another alternative embodiment, the energy conduits A-G
are individually switched between the same electrical polarity and
the delivery member/tube 1006 conducts an opposite/alternating
polarity to that of the energy conduits A-G. In yet another
alternative embodiment, the delivery member/tube 1006 and energy
conduits A-G are of a single electrical polarity and one or more
secondary grounding pads are used therewith to provide an opposite
polarity member.
[0043] In operation, the tissue ablation system of an embodiment
delivers energy to target tissue via the energy conduits A-G. The
energy includes, for example, radio frequency (RF) energy, but is
not so limited. The energy is delivered via any of a number of
techniques. The energy can be applied via pulsed waveforms and/or
continuous waveforms, but is not so limited.
[0044] In an example procedure that includes use of the tissue
ablation system, energy can be applied to energy conduits A-G
during deployment of the energy conduits A-G into the target
tissue. The energy can be applied automatically or, alternatively,
manually as a procedure progresses and as appropriate to the
procedure. Also, the energy delivered to the target tissue can be
adjusted during the procedure by adjusting any of the power level,
the waveforms, and a combination of the power level and the
waveform.
[0045] In another example procedure that includes use of the tissue
ablation system, energy can be applied to energy conduits A-G
following deployment of the energy conduits A-G into the target
tissue. The energy can be applied automatically or, alternatively,
manually as appropriate to the procedure. Also, the energy
delivered to the target tissue can be adjusted manually and/or
automatically during the procedure by adjusting any of the power
level, the waveforms, and a combination of the power level and the
waveform.
[0046] In addition to the components of the tissue ablation device
1000, various sensing techniques can be used to guide or control
the progress of the tissue ablation. For example temperature
sensors can be imbedded or attached to at least one of the energy
conduits A-G and the delivery member/tube 1006 to provide feedback
to a user and/or an energy controller. Additionally, a variety of
sensors can be deployed from the tissue ablation device 1000 into
tissue of the target tissue.
[0047] In addition to the components of the tissue ablation systems
described above, various sensing techniques can be used with and/or
coupled to the tissue ablation system to guide or control the
progress of the tissue ablation. For example temperature sensors
can be imbedded or attached to the deployable energy conduits and
provide feedback to a user or an energy controller. A variety of
sensors can also be deployed from the device into tissue within the
targeted tissue, in this case a sphere.
[0048] FIG. 11 is a distal portion 1100 of a tissue ablation device
including a delivery member/tube 1106, a plurality of primary
energy conduits R, S, T, U, W, X, Y, Z (collectively referred to as
R-Z), and a plurality of secondary energy conduits H, I, J, K, L,
M, N, and P (collectively referred to as H-P) and Q in a deployed
state, under yet another alternative embodiment. For clarity
electrodes H, I, K, M, P, S, T, U, X, Y, and Z have been omitted in
the side view of the device shown in FIG. 11. The primary R-Z and
secondary H-P energy conduits comprise nickel titanium alloy, for
example, but can be formed from any number/combination of materials
some of which are described above. Further, the outside diameter of
the primary R-Z and secondary H-P energy conduits of an embodiment
is approximately in the range of 0.010 to 0.080 inches, but is not
so limited.
[0049] As described above, the delivery member/tube 1106 provides
sufficient support for placement of the primary energy conduits
R-Z. Likewise the primary energy conduits R-Z provide sufficient
support for placement of the secondary energy conduits H-P. While
the tissue ablation device of an embodiment deploys one secondary
energy conduit from one or more distal and/or lateral ports in a
distal region of each primary energy conduit, alternative
embodiments of the tissue ablation device can deploy more than one
secondary energy conduit from one or more distal and/or lateral
ports of each primary energy conduit. Advancement of a deployment
slider (not shown) as described above advances and deploys the
energy conduits R-Z, H-P, and Q to a deployed state or shape in
target tissue. The energy conduits R-Z, H-P in a deployed state
form a series of approximately semi-spherical segments which when
taken together in this embodiment form the outline of a sphere 1199
that fully encompasses a volume of tissue targeted for ablation.
The application of RF energy to the energy conduits R-Z, H-P, and Q
generates or produces a spherical volume of ablated tissue.
[0050] The energy conduits R-Z, H-P, and Q of an embodiment are
configured to each have an alternating electrical polarity. The
energy conduits of an alternative embodiment conduct electrical
energy of a single electrical polarity, with the delivery
member/tube 1106 conducting electrical energy having an opposite
polarity. In still another alternative embodiment, the energy
conduits H-P and R-Z are individually switched between the same
electrical polarity and electrode Q is coupled to conduct
electrical energy of an opposite/alternating polarity to that of
the energy conduits H-P and R-Z. In yet another alternative
embodiment, all energy conduits R-Z, H-P, and Q are of a single
electrical polarity and one or more secondary grounding pads are
used therewith to provide an opposite polarity member. In still
another embodiment, electrode Q is not present and energy passes
within the remaining electrodes.
[0051] In operation, the tissue ablation system of an embodiment
delivers energy to target tissue via the energy conduits R-Z, H-P,
and Q. The energy includes, for example, radio frequency (RF)
energy, but is not so limited. The energy is delivered via any of a
number of techniques, some of which are described herein. The
energy can be applied via pulsed waveforms and/or continuous
waveforms, but is not so limited.
[0052] In an example procedure that includes use of the tissue
ablation system, energy can be applied to energy conduits R-Z, H-P,
and Q during deployment of the energy conduits R-Z, H-P, and Q into
the target tissue. The energy can be applied automatically or,
alternatively, manually as a procedure progresses and as
appropriate to the procedure. Also, the energy delivered to the
target tissue can be adjusted during the procedure by adjusting any
of the power level, the waveforms, and a combination of the power
level and the waveform.
[0053] In another example procedure that includes use of the tissue
ablation system, energy can be applied to energy conduits R-Z, H-P,
and Q following deployment of the energy conduits R-Z, H-P, and Q
into the target tissue. The energy can be applied automatically or,
alternatively, manually as appropriate to the procedure. Also, the
energy delivered to the target tissue can be adjusted manually
and/or automatically during the procedure by adjusting any of the
power level, the waveforms, and a combination of the power level
and the waveform.
[0054] In addition to the components of the tissue ablation device
1100, various sensing techniques can be used to guide or control
the progress of the tissue ablation. For example temperature
sensors can be imbedded or attached to at least one of the energy
conduits R-Z, H-P, and Q and the delivery member/tube 1106 to
provide feedback to a user and/or an energy controller.
Additionally, a variety of sensors can be deployed from the tissue
ablation device 1100 into tissue of the target tissue.
[0055] In addition to the components of the tissue ablation systems
described above, various sensing techniques can be used with and/or
coupled to the tissue ablation system to guide or control the
progress of the tissue ablation. For example temperature sensors
can be imbedded or attached to the deployable energy conduits and
provide feedback to a user or an energy controller. A variety of
sensors can also be deployed from the device into tissue within the
targeted tissue, in this case a sphere.
[0056] FIG. 12 is a flow diagram of tissue ablation procedure using
the tissue ablation device, under an embodiment. In operation
generally a user positions the tissue ablation device in the target
biological tissue as appropriate to a medical procedure, at block
1202. Placement of the tissue ablation device in the target tissue
can include the use of various visualization methods such as
ultrasound stenography, Computerized Tomography (CT), and Magnetic
Resonance Imaging (MRI), but is not so limited.
[0057] Following placement of the device in the target tissue the
user deploys the electrodes in the target tissue, at block 1204.
Power or energy is applied to the target tissue via the electrodes,
at block 1206. The energy generates a volume of ablated tissue
having a shape and size appropriate to the configuration of the
deployed electrodes, at block 1208. The user retracts the
electrodes and removes the device from the target tissue, at block
1210.
[0058] As described above, the tissue ablation system of an
embodiment delivers energy to target tissue via the energy conduits
or electrodes. The energy includes, for example, radio frequency
(RF) energy, but is not so limited. The energy is delivered via any
of a number of techniques. The energy can be applied via pulsed
waveforms and/or continuous waveforms, but is not so limited.
[0059] In an example procedure that includes use of the tissue
ablation system, energy can be applied to energy conduits during
deployment of the energy conduits into the target tissue. The
energy can be applied automatically or, alternatively, manually as
a procedure progresses and as appropriate to the procedure. Also,
the energy delivered to the target tissue can be adjusted during
the procedure by adjusting any of the power level, the waveforms,
and a combination of the power level and the waveform.
[0060] In another example procedure that includes use of the tissue
ablation system, energy can be applied to energy conduits following
deployment of the energy conduits into the target tissue. The
energy can be applied automatically or, alternatively, manually as
appropriate to the procedure. Also, the energy delivered to the
target tissue can be adjusted manually and/or automatically during
the procedure by adjusting any of the power level, the waveforms,
and a combination of the power level and the waveform.
[0061] As described above, the application of power to the target
tissue under an embodiment is controlled automatically and/or
manually under a number of procedures. A first type of procedure
uses a predetermined pattern of energy delivery according to a time
schedule. A second type of procedure varies the application of
energy to the target tissue volume in accordance with temperature
information or feedback parameters of the tissue. A third type of
procedure varies the application of energy to the target tissue
volume in accordance with impedance information or feedback
parameters of the tissue in combination with elapsed time. A fourth
type of procedure varies the application of energy to the target
tissue volume in accordance with impedance information or feedback
parameters of the tissue. A fifth type of procedure varies the
application of energy to the target tissue volume in accordance
with temperature and impedance information or feedback parameters
of the tissue.
[0062] Note that patent and procedure selection is the
responsibility of the medical professional/user and the outcome is
dependent on many variables, including patient anatomy, pathology,
and surgical techniques. Use of the tissue ablation device, system
and methods described herein for tissue ablation can result in
localized elevated temperatures that can cause thermal injury to
the skin. In addition, tissue or organs adjacent to the tissue
being ablated may be injured thermally. To minimize the potential
for thermal injury to the skin or adjacent tissues,
temperature-modifying measures can be initiated at the physician's
discretion. These may include applying a sterile ice pack or
saline-moistened gauze to cool and/or separate tissues, but are not
so limited.
[0063] Unless the context clearly requires otherwise, throughout
the description and the claims, the words "comprise," "comprising,"
and the like are to be construed in an inclusive sense as opposed
to an exclusive or exhaustive sense; that is to say, in a sense of
"including, but not limited to." Words using the singular or plural
number also include the plural or singular number respectively.
Additionally, the words "herein," "hereunder," "above," "below,"
and words of similar import refer to this application as a whole
and not to any particular portions of this application. When the
word "or" is used in reference to a list of two or more items, that
word covers all of the following interpretations of the word: any
of the items in the list, all of the items in the list and any
combination of the items in the list.
[0064] The above description of illustrated embodiments of the
tissue ablation devices and methods is not intended to be
exhaustive or to limit the systems and methods to the precise form
disclosed. While specific embodiments of, and examples for, the
tissue ablation devices and methods are described herein for
illustrative purposes, various equivalent modifications are
possible within the scope of the systems and methods, as those
skilled in the relevant art will recognize. The teachings of the
tissue ablation devices and methods provided herein can be applied
to other medical systems, not only for the medical systems
described above.
[0065] The elements and acts of the various embodiments described
above can be combined to provide further embodiments. These and
other changes can be made to the tissue ablation devices and
methods in light of the above detailed description.
[0066] The above references and United States Patent applications
are incorporated herein by reference. Aspects of the tissue
ablation devices and methods can be modified, if necessary, to
employ the systems, functions and concepts of the various patents
and applications described above to provide yet further embodiments
of the tissue ablation devices and methods.
[0067] In general, in the following claims, the terms used should
not be construed to limit the tissue ablation devices and methods
to the specific embodiments disclosed in the specification and the
claims, but should be construed to include all medical devices and
systems that operate under the claims to provide tissue ablation
and/or tissue resection. Accordingly, the tissue ablation devices
and methods are not limited by the disclosure, but instead the
scope of the systems and methods is to be determined entirely by
the claims.
[0068] While certain aspects of the tissue ablation devices and
methods are presented below in certain claim forms, the inventors
contemplate the various aspects of the systems and methods in any
number of claim forms. Accordingly, the inventors reserve the right
to add additional claims after filing the application to pursue
such additional claim forms for other aspects of the tissue
ablation devices and methods.
* * * * *