U.S. patent application number 15/419269 was filed with the patent office on 2017-08-03 for cavitary tissue ablation system.
The applicant listed for this patent is Innoblative Designs, Inc.. Invention is credited to Alyssa Bailey, Ryan M. Bean, Michelle Hasse, Robert F. Rioux, Tyler Wanke.
Application Number | 20170215947 15/419269 |
Document ID | / |
Family ID | 59385191 |
Filed Date | 2017-08-03 |
United States Patent
Application |
20170215947 |
Kind Code |
A1 |
Rioux; Robert F. ; et
al. |
August 3, 2017 |
CAVITARY TISSUE ABLATION SYSTEM
Abstract
The invention is a tissue ablation system including an ablation
device having an electrode array configured for the ablation of
tissue, wherein the electrode array includes a plurality of
conductive wires electrically isolated and independent from one
another and configured to receive electrical current from a source
and emit radiofrequency (RF) energy in response. The ablation
system further includes a controller configured to control an
emission pattern from the electrode array, either by independently
controlling activation of one or more conductive wires or by
actively blocking emission of energy from a selected one or more
conductive wires or by adjusting flow of a conductive fluid for
carrying RF energy emitted in a virtual electrode arrangement.
Accordingly, the system provides a user with custom ablation
shaping including custom, user-defined ablation geometries or
profiles for RF emission in a desired shape or pattern so as to
deliver targeted treatment to marginal tissue.
Inventors: |
Rioux; Robert F.; (Ashland,
MA) ; Bailey; Alyssa; (Chicago, IL) ; Bean;
Ryan M.; (Westminster, MA) ; Wanke; Tyler;
(Chicago, IL) ; Hasse; Michelle; (Eau Claire,
MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Innoblative Designs, Inc. |
Chicago |
IL |
US |
|
|
Family ID: |
59385191 |
Appl. No.: |
15/419269 |
Filed: |
January 30, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62290108 |
Feb 2, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2018/00708
20130101; A61B 2018/00791 20130101; A61B 18/1492 20130101; A61B
2018/144 20130101; A61B 18/1477 20130101; A61B 2018/0016 20130101;
A61B 2017/00053 20130101; A61B 2017/00057 20130101; A61B 2018/00875
20130101; A61B 2018/00744 20130101; A61B 18/148 20130101; A61B
2018/00761 20130101; A61B 2018/00839 20130101; A61B 2018/00726
20130101; A61B 2018/124 20130101; A61B 2018/00648 20130101; A61B
18/1206 20130101; A61B 2018/00577 20130101; A61B 2018/00333
20130101; A61B 2018/00267 20130101; A61B 2090/0436 20160201; A61B
2018/00886 20130101; A61B 2018/00827 20130101; A61B 2218/002
20130101; A61B 2018/1417 20130101; A61B 2018/0072 20130101; A61B
90/04 20160201; A61B 2018/00988 20130101 |
International
Class: |
A61B 18/14 20060101
A61B018/14 |
Claims
1. A medical device for selectively ablating tissue, the device
comprising: a probe comprising a nonconductive elongated shaft and
a nonconductive distal portion extending from the shaft; an
electrode array comprising a plurality of independent conductive
wires positioned along an exterior surface of the nonconductive
distal portion; and a controller coupled to the conductive wires
and comprising a plurality of selectable inputs associated with the
plurality of conductive wires, wherein, when an input is selected
by a user, the selected input is configured to control supply of
electrical current from a source to at least one conductive wire
associated with the selected input to either activate a portion of
the electrode array for ablation of a tissue adjacent to the
activated portion of the electrode array or inactivate the portion
of the electrode array to prevent or cease ablation of a tissue
adjacent to the inactivated portion of the electrode array.
2. The medical device of claim 1, wherein the controller comprises
a display for providing a visual indication of both activated and
inactivated portions of the electrode array.
3. The medical device of claim 2, wherein the display is configured
to provide a visual indication of a status of each of the plurality
of conductive wires, wherein the status comprises either an active
status or an inactive status.
4. The medical device of claim 3, wherein the active status
indicates that a conductive wire is receiving electrical current
and the inactive status indicates that a conductive wire is not
receiving electrical current.
5. The medical device of claim 4, wherein the number of selectable
inputs corresponds to the number of conductive wires such that each
conductive wire is associated with a single selectable input.
6. The medical device of claim 5, wherein, upon selection of a
first input by a user, the selected first input is configured to
control supply of electrical current to a corresponding first
conductive wire, wherein the display provides a visual indication
of the status of the first conductive wire of either being active
or inactive.
7. The medical device of claim 1, wherein the controller is
configured to control one or more parameters associated with
controlling supply of electrical current to one or more of the
conductive wires.
8. The medical device of claim 7, wherein the one or more
parameters comprises at least one of a level of electrical current
to be supplied, a length of time in which electrical current is to
be supplied, one or more intervals over which the electrical
current is to be supplied, or a combination thereof
9. A medical device for selectively ablating tissue, the device
comprising: a probe comprising a nonconductive elongated shaft and
a nonconductive distal portion extending from the shaft; an
electrode array comprising a plurality of independent conductive
wires positioned along an exterior surface of the nonconductive
distal portion, wherein each of the conductive wires is configured
to convey energy away from the nonconductive distal portion upon
receipt of an electrical current for ablation of a tissue, the
energy including radio frequency (RF) energy; and at least one
nonconductive cap member coupled to the probe and selectively
positionable over a portion of the electrode array to block
emission of energy from one or more one conductive wires while
permitting emission of energy from remaining uncovered conductive
wires so as to allow ablation of tissue in a desired pattern.
10. The medical device of claim 9, further comprising a controller
operably coupled to the nonconductive cap member and comprising one
or more selectable inputs which, when selected by a user, at least
one of the selected inputs is configured to control positioning of
the nonconductive cap member relative to the electrode array.
11. The medical device of claim 10, wherein the electrode array
comprises a plurality of different ablation portions arranged about
the nonconductive distal portion.
12. The medical device of claim 11, wherein the plurality of
different ablation portions comprises at least four quadrants of
the electrode array corresponding to at least four sides of the
nonconductive distal portion.
13. The medical device of claim 12, wherein the nonconductive cap
member is configured to be selectively positioned over at least one
of the four quadrants to block emission of energy from one or more
conductive wires within the quadrant while permitting emission of
energy from one or more conductive wires within the other
quadrants.
14. The medical device of claim 10, wherein at least one of the
selectable inputs is configured to rotate the nonconductive cap
member relative to a longitudinal axis of the nonconductive distal
portion.
15. A medical device for selectively ablating tissue, the device
comprising: a probe comprising a nonconductive elongated shaft
having at least one lumen therethrough and a nonconductive distal
portion extending from the elongated shaft, the nonconductive
distal portion comprising: at least two internal chambers, each
chamber having an inlet port configured to receive delivery of a
fluid from the probe and one or more perforations in a wall of the
chamber, the one or more perforations configured to allow passage
of the fluid from the chamber to an exterior surface of the
nonconductive distal portion; at least one flow control member
associated with each of the chambers and configured to transition
between open, closed, and intermediate positions to control the
passage of fluid through the one or more perforations to the
exterior surface of the nonconductive distal portion; and an
electrode array comprising a plurality of independent conductive
wires positioned along an exterior surface of the nonconductive
distal portion, wherein each of the conductive wires is configured
to conduct energy upon receipt of an electrical current, the energy
to be carried by the fluid flowing from the chamber to the exterior
surface of the nonconductive distal portion for ablation of tissue
in a desired pattern based on the positioning of the flow control
member in each chamber.
16. The medical device of claim 15, wherein each flow control
member is disposed within the associated chamber and selectively
positionable over the inlet port so as to control the flow rate of
fluid into the associated chamber to subsequently control the flow
rate of fluid through the one or more perforations to the exterior
surface of the nonconductive distal portion.
17. The medical device of claim 16, wherein each flow control
member is configured to at least partially engage the inlet port to
partially restrict or completely block the delivery of fluid into
the chamber and further partially restrict or completely prevent
the passage of fluid through the one or more perforations to the
exterior surface of the nonconductive distal portion to thereby
control the degree of ablation or prevent ablation of adjacent
tissue relative to the associated chamber.
18. The medical device of claim 16, wherein at least one flow
control member comprises a plunger.
19. The medical device of claim 18, further comprising a controller
operably coupled to the plunger, the controller comprising at least
one selectable input which, when selected by a user, is configured
to allow a user to selectively control position of the plunger
relative to the inlet port of the associated chamber to thereby
control flow rate of the fluid.
20. The medical device of claim 16, wherein at least one flow
control member comprises an adjustable aperture mechanism
associated with an inlet port.
21. The medical device of claim 20, wherein the adjustable aperture
mechanism comprises a contractable/expandable aperture configured
to transition between an open position, a closed position, and one
or more intermediate positions.
22. The medical device of claim 21, wherein, when in a closed
position, the aperture is configured to prevent the passage of
fluid through the one or more perforations to the exterior surface
of the nonconductive distal portion to thereby prevent ablation of
adjacent tissue relative to the associated chamber and, when in an
open position, the aperture is configured to permit the passage of
fluid through the one or more perforations to the exterior surface
of the nonconductive distal portion to thereby allow ablation of
adjacent tissue relative to the associated chamber.
23. The medical device of claim 21, wherein, when in an
intermediate position, the aperture is configured to partially
restrict the passage of fluid through the one or more perforations
to the exterior surface of the nonconductive distal portion to
thereby control the degree of ablation of adjacent tissue relative
to the associated chamber.
24. The medical device of claim 16, wherein the at least two
internal chambers correspond to at least two halves of the
nonconductive distal portion, the at least two halves corresponding
to at least two quadrants of the electrode array, each quadrant
includes at least one of the conductive wires.
25. The medical device of claim 24, wherein ablation of tissue
adjacent to one of the two quadrants is controlled via positioning
of a flow control member in a corresponding internal chamber.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of, and priority to,
U.S. Provisional Application No. 62/290,108, filed Feb. 2, 2016,
the content of which is incorporated by reference herein in its
entirety.
FIELD
[0002] The present disclosure relates generally to medical devices,
and, more particularly, to a cavitary tissue ablation system
including an ablation device to be delivered to a tissue cavity and
configured to emit energy in a desired shape or pattern based on
custom, user-defined ablation geometries or profiles so as to
deliver treatment for the ablation and destruction of a targeted
portion of marginal tissue around the tissue cavity.
BACKGROUND
[0003] Cancer is a group of diseases involving abnormal cell growth
with the potential to invade or spread to other parts of the body.
Cancer generally manifests into abnormal growths of tissue in the
form of a tumor that may be localized to a particular area of a
patient's body (e.g., associated with a specific body part or
organ) or may be spread throughout. Tumors, both benign and
malignant, are commonly treated and removed via surgical
intervention, as surgery often offers the greatest chance for
complete removal and cure, especially if the cancer has not spread
to other parts of the body. Electrosurgical methods, for example,
can be used to destroy these abnormal tissue growths. However, in
some instances, surgery alone is insufficient to adequately remove
all cancerous tissue from a local environment.
[0004] For example, treatment of early stage breast cancer
typically involves a combination of surgery and adjuvant
irradiation. Unlike a mastectomy, a lumpectomy removes only the
tumor and a small rim (area) of the normal tissue around it.
Radiation therapy is given after lumpectomy in an attempt to
eradicate cancer cells that may remain in the local environment
around the removed tumor, so as to lower the chances of the cancer
returning. However, radiation therapy as a post-operative treatment
suffers various shortcomings. For example, radiation techniques can
be costly and time consuming, and typically involve multiple
treatments over weeks and sometimes months. Furthermore, radiation
often results in unintended damage to the tissue outside the target
zone. Thus, rather than affecting the likely residual tissue,
typically near the original tumor location, radiation techniques
often adversely affect healthy tissue, such as short and long-term
complications affecting the skin, lungs, and heart.
[0005] Accordingly, such risks, when combined with the burden of
weeks of daily radiation, may drive some patients to choose
mastectomy instead of lumpectomy. Furthermore, some women (e.g., up
to thirty percent (30%)) who undergo lumpectomy stop therapy before
completing the full treatment due to the drawbacks of radiation
treatment. This may be especially true in rural areas, or other
areas in which patients may have limited access to radiation
facilities.
SUMMARY
[0006] Tumors, both benign and malignant, are commonly treated and
destroyed via surgical intervention, as surgery often offers the
greatest chance for complete removal and cure, especially if the
cancer has not metastasized. However, after the tumor is destroyed,
a hollow cavity may remain, wherein tissue surrounding this cavity
and surrounding the original tumor site can still leave abnormal or
potentially cancerous cells that the surgeon fails, or is unable,
to excise. This surrounding tissue is commonly referred to as
"margin tissue" or "marginal tissue", and is the location within a
patient where a reoccurrence of the tumor may most likely
occur.
[0007] Some alternative treatments to using radiation therapy
include the use of ablation devices to be inserted within cavitary
excisional beds and deliver radiofrequency (RF) energy to marginal
tissue surrounding the cavity following the procedure. For example,
one type of proposed ablation applicator includes a long rigid
needle-based electrode applicator for delivery of RF energy to
marginal tissue upon manual manipulation by a surgeon or operator.
Another type of ablation application includes an umbrella-type
array of electrodes jointly connected to one another and deployable
in an umbrella-like fashion to deliver RF energy.
[0008] While current ablation devices may provide some form tissue
ablation, none have proven to meet all needs and circumstances
encountered when performing marginal cavity tissue ablation. For
example, in certain instances, it may be desirable to create a
non-uniform ablation within a tissue cavity. In some instances,
vital organs or critical internal/external structures (e.g., bone,
muscle, skin, etc.) may be in close proximity to a tissue cavity
and any unintended exposure to RF energy could have a negative
impact. Current RF ablation devices are unable to provide precise
control over the emission of RF energy such that they lack the
ability to effectively prevent emission from reaching vital organs
or important internal/external structures during the ablation
procedure. In particular, the long rigid needle-based electrode RF
applicators generally require the surgeon or operator to manually
adjust needle locations, and possibly readjust several electrodes
multiple times, in order to control an ablation, which may lead to
inaccuracy and difficulty in directing RF emission. The umbrella
array RF applicators are limited by their physical geometry, in
that the umbrella array may not be designed to fit within a cavity.
Additionally, or alternatively, the uniform potential distribution
of an umbrella array, as a result of the electrodes being jointly
connected to one another, results in a tissue ablation geometry
that is not adjustable without physically moving the umbrella
array, thus resulting in similar problems as long rigid
needle-based RF applicators.
[0009] The tissue ablation system of the present disclosure can be
used during an ablation procedure to destroy the thin rim of
marginal tissue around the cavity in a targeted manner. In
particular, the present disclosure is generally directed to a
cavitary tissue ablation system including an ablation device to be
delivered into a tissue cavity and configured to emit non-ionizing
radiation, such as radiofrequency (RF) energy, in a desired shape
or pattern so as to deliver treatment for the ablation and
destruction of a targeted portion of marginal tissue around the
tissue cavity. The system of the present invention is configured to
provide a user with custom ablation shaping, which includes the
creation of custom, user-defined ablation geometries depending on
the target site. In particular, rather than simply providing a
universal RF ablation shape or profile, the system allows for a
user to customize the emission of energy to a targeted portion of
marginal tissue within the cavity, which is particularly useful in
instances in which non-uniform ablation is desired. The customized
emission of energy may include a specific shape or geometry of
emission, as well as time and depth of penetration of RF
energy.
[0010] The devices, systems, and methods of the present disclosure
can help to ensure that all microscopic disease in the local
environment has been treated. This is especially true in the
treatment of tumors that have a tendency to recur. Furthermore, by
providing custom ablating shaping, in which the single ablation
device may provide numerous RF energy emission shapes or profiles,
the system of the present invention allows for non-uniform ablation
to occur. This is particularly useful in controlling ablation shape
so as to avoid vital organs and any critical internal/external
structures (e.g., bone, muscle, skin) in close proximity to the
tumor site, while ensuring that residual marginal tissue within the
local environment has been treated.
[0011] The tissue ablation device of the present invention
generally includes a probe including an elongated shaft configured
as a handle and adapted for manual manipulation and a nonconductive
distal portion coupled to the shaft. The nonconductive distal
portion includes an electrode array positioned along an external
surface thereof. The distal portion, including the electrode array,
can be delivered to and maneuvered within a tissue cavity (e.g.,
formed from tumor removal) and configured to ablate marginal tissue
(via RF energy) immediately surrounding the tissue cavity in order
to minimize recurrence of the tumor. The ablation device of the
present invention is further configured to provide a user with
custom ablation shaping, which includes the creation of custom,
user-defined ablation geometries or profiles.
[0012] In one aspect, the electrode array includes a plurality of
conductive wires electrically isolated and independent from one
another. This design allows for each conductive wire to receive
energy in the form of electrical current from a source (e.g., RF
generator) and emit RF energy in response. The system may include a
device controller, for example, configured to selectively control
the supply of electrical current to each of the conductive wires.
By allowing for independent control of each wire, the ablation
system provides for custom ablation shaping to occur. In
particular, the device controller allows for individual conductive
wires, or a designated combination of conductive wires, to be
controlled so as to result in the activation (e.g., emission of RF
energy) of corresponding portions of the electrode array.
[0013] The device controller can selectively activate one or more
of the electrode array portions (e.g., control the supply of
electrical current to specific sets of conductive wires) so as to
provide targeted delivery of RF energy from the ablation device in
a desired pattern or shape. In addition to customizing the shape or
geometry of RF energy emission from the ablation device, the device
controller may be further configured to control particular ablation
parameters, such as control of timing of the emission (e.g., length
of time, intervals, etc.) as well as the depth of RF energy
penetration.
[0014] In one aspect, the device controller may be configured to be
operated manually, such that an operator (e.g., surgeon or
operator) may input a desired ablation shape or pattern and
associated parameters. For example, the controller may be coupled
to the conductive wires and may include a plurality of selectable
inputs associated with the plurality of conductive wires. When one
of the plurality of inputs is selected by a user, the selected
input is configured to control supply of electrical current from a
source to at least one conductive wire associated with the selected
input to either activate a portion of the electrode array for
ablation of a tissue adjacent to the activated portion of the
electrode array or inactivate the portion of the electrode array to
prevent or cease ablation of a tissue adjacent to the inactivated
portion of the electrode array. The controller may include a
display for providing a visual indication of both activated and
inactivated portions of the electrode array. In particular, the
display is configured to provide a visual indication of a status of
each of the plurality of conductive wires, wherein the status
includes either an active status or an inactive status. The active
status indicates that a conductive wire is receiving electrical
current and the inactive status indicates that a conductive wire is
not receiving electrical current.
[0015] In another aspect, the tissue ablation device may include a
nonconductive cap member selectively positionable over one or more
portions of the electrode array so as to block emission of energy
therefrom while permitting the emission of energy from remaining
portions of the electrode array. Accordingly, the nonconductive cap
member allows for the ablation of a target tissue in a specific
pattern, as dictated by the physical coverage of the cap member. In
some embodiments, the electrode array is composed of a plurality of
conductive wires and the electrode array may be partitioned into
specific portions which may correspond to portions or sides of the
distal portion of the device. In one embodiment, the electrode
array may include four distinct portions (i.e., individual or sets
of conductive wires) corresponding to four sides of the distal
portion (e.g., four sides or quadrants around spheroid body).
Accordingly, the nonconductive cap member may be selectively
positionable over one or more of the plurality of conductive wires
so as to block emission of energy from such wires and preventing
emission from the corresponding portion of the electrode array,
while permitting the remaining wires to emit energy.
[0016] In some embodiments, the nonconductive cap member may have a
predefined shaped or size, such that the cap member has a fixed
area of coverage (e.g., is limited covering a specific number of
conductive wires or number of electrode array portions). For
example, the cap member may be shaped or sized to cover a single
quadrant of a spheroid distal portion, such that, at any given
time, three out of four quadrants will remain uncovered and thus
emit RF energy in a corresponding pattern. In other embodiments,
the nonconductive cap member may be shaped or sized to cover more
than one quadrant (e.g., at least two quadrants, at least three
quadrants, etc.).
[0017] In some embodiments, the ablation device is configured to
provide RF ablation via a virtual electrode arrangement, which
includes distribution of a fluid along an exterior surface of the
distal tip and, upon activation of the electrode array, the fluid
may carry, or otherwise promote, energy emitted from the electrode
array to the surrounding tissue.
[0018] For example, in one aspect, the nonconductive distal portion
of the ablation device includes at least two internal chambers
configured to receive and retain a fluid therein. Each chamber
includes an inlet port configured to receive the fluid and one or
more perforations in a wall of the chamber and configured to allow
fluid to pass therethrough, or weep, from the chamber to an
external surface of the distal portion. As previously described,
the ablation device further includes an electrode array positioned
along an external surface of the distal portion. Upon positioning
the distal portion within a target site (e.g., tissue cavity to be
ablated), the electrode array can be activated. The fluid weeping
through the perforations of the internal chambers and to the outer
surface of the distal portion is a conductive fluid (e.g., saline)
and thus able to carry or promote energy from the electrode array,
such that energy is transmitted from the electrode array to the
tissue by way of the fluid weeping from the perforations, thereby
creating a virtual electrode. Accordingly, upon the fluid weeping
through the perforations, a pool or thin film of fluid is formed on
the exterior surface of the distal portion and is configured to
ablate surrounding tissue via the electrical current carried from
the electrode array.
[0019] In this embodiment, the ablation device further includes at
least one flow control member associated with each chamber. The at
least one flow control member is configured to transition between
open, closed, and intermediate positions so as to ultimately
control the passage of fluid through the one or more perforations
to the external surface of the distal portion, thereby effectively
controlling the ablation pattern or shape. In particular, in the
event that a flow control member associated with a first internal
chamber is completely closed, thereby preventing flow of fluid
through the perforations of the first internal chamber, ablation is
prevented from occurring along an external surface of the distal
portion associated with the first internal chamber. Alternatively,
in the event that the flow control member associated with the first
internal chamber is completely opened, thereby allowing flow
weeping of fluid through the perforations, ablation is allowed to
occur along the external surface of the distal portion associated
with the first internal chamber. Accordingly, a user may manually
manipulate each flow control member of the at least two internal
chambers so as to effect the ablation shape or geometry.
[0020] In some embodiments, the flow control member may include a
plunger positioned within each of the internal chambers and
selectively positionable over the inlet port so as to control the
flow rate of fluid into the associated chamber to subsequently
control the flow rate of fluid through the one or more perforations
to the external surface of the distal portion. In other
embodiments, the flow control member includes a
contractable/expandable aperture serving as the inlet port and
configured to control the flow rate of fluid into the associated
chamber to subsequently control the flow rate of fluid weeping
through the perforations. In both embodiments, the plunger and
contractable/expandable aperture are coupled to controllers
allowing a user to selectively control position of the plunger or
contractable/expandable aperture.
[0021] It should be noted the devices of the present disclosure are
not limited to such post-surgical treatments and, as used herein,
the phrase "body cavity" may include non-surgically created
cavities, such as natural body cavities and passages, such as the
ureter (e.g. for prostate treatment), the uterus (e.g. for uterine
ablation or fibroid treatment), fallopian tubes (e.g. for
sterilization), and the like. Additionally, or alternatively,
tissue ablation devices of the present disclosure may be used for
the ablation of marginal tissue in various parts of the body and
organs (e.g., lungs, liver, pancreas, etc.) and is not limited to
treatment of breast cancer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Features and advantages of the claimed subject matter will
be apparent from the following detailed description of embodiments
consistent therewith, which description should be considered with
reference to the accompanying drawings, wherein:
[0023] FIG. 1 is a schematic illustration of an ablation system
consistent with the present disclosure;
[0024] FIG. 2 is a perspective view of an ablation device tip of
the ablation system of FIG. 1;
[0025] FIGS. 3A, 3B, and 3C are perspective views of the ablation
device tip of FIG. 2 in greater detail;
[0026] FIG. 4 is a block diagram illustrating the custom ablation
system of the device controller in greater detail;
[0027] FIG. 5 is a top view of one embodiment of device controller
configured for individually controlling operational modes of each
of the plurality of conductive wires of the electrode array of the
ablation device tip;
[0028] FIG. 6A is a top view of the device controller in a first
mode and FIG. 6B is a front view of the ablation device tip
illustrating the electrode array operating in the first mode;
[0029] FIG. 7A is a top view of the device controller in a second
mode and FIG. 7B is a front view of the ablation device tip
illustrating the electrode array operating in the second mode;
[0030] FIGS. 8A-8E are perspective views of a distal tip of the
ablation device of FIG. 1 illustrating various electrode array
configurations;
[0031] FIG. 9 is a side view of the distal tip of the ablation
device of FIG. 1 including several sides. Each side includes one or
more independently connected electrodes, which enables differential
function and current independent drives and/or measurements;
[0032] FIGS. 10-10D are side and perspective views of the distal
tip of the application device illustrating the different sides of
FIG. 9;
[0033] FIG. 11A is a perspective view of a distal tip of an
application device consistent with the present disclosure
illustrating a nonconductive cap member coupled to the distal tip
and configured to block emission of energy from at least one of the
conductive wires;
[0034] FIG. 11B is a front view of the distal tip of FIG. 11A
illustrating energy emission from the distal tip in a specific
pattern as dictated by the blockage of energy emission by the
nonconductive cap member;
[0035] FIG. 11C is a front view of the distal tip of FIG. 11A
illustrating rotational movement of the nonconductive cap
member;
[0036] FIG. 12 is an exploded perspective view of an ablation
device consistent with the present disclosure;
[0037] FIG. 13A is a front view of one embodiment of a distal tip
of the ablation device of FIG. 12 illustrating one or more chambers
formed within the distal tip;
[0038] FIG. 13B is a sectional view of one embodiment of the
ablation device of FIG. 12 taken along lines A-A, illustrating at
least two of the chambers within the distal tip;
[0039] FIG. 14A is a rear view of the distal tip, in a direction
from the neck towards the spheroid body, providing a view into the
cavity of the distal tip and further illustrating a
contractable/expandable aperture for each chamber to control
passage of fluid therethrough;
[0040] FIG. 14B illustrates an exemplary control member coupled to
one of the contractable/expandable apertures and configured to
control contraction/expansion of the aperture;
[0041] FIG. 15 is a sectional view of the ablation device of FIG.
12 illustrating a moveable plunger within each chamber and
configured to move relative to the inlet port so as to allow
control of passage of fluid into the inlet port and subsequent
passage of fluid through one or more perforations in a chamber and
to an external surface of the distal tip;
[0042] FIGS. 16 and 17 are perspective and exploded perspective
views, respectively, of one embodiment of a device controller
consistent with the present disclosure;
[0043] FIG. 18 is an exploded perspective view of another
embodiment of an ablation device consistent with the present
disclosure;
[0044] FIG. 19 is a plan view of the ablation device of FIG. 18
illustrating the two halves of the device separated from one
another and showing the external surface of each;
[0045] FIG. 20 is a plan view of the ablation device of FIG. 18
illustrating the two halves of the device separated from one
another and showing the interior surface of each;
[0046] FIGS. 21A and 22B are enlarged views of the spheroid body of
the first halve of the device showing the exterior and interior
surfaces, respectively, and further illustrating the particular
arrangement of first and second conductive wires extending through
proximal and distal ports of the spheroid body;
[0047] FIGS. 22A and 22B are enlarged views of the spheroid body of
the second halve of the device showing the exterior and interior
surfaces, respectively, and further illustrating the particular
arrangement of third and fourth conductive wires extending through
proximal and distal ports of the spheroid body;
[0048] FIG. 23 is a schematic illustration of the ablation device
of FIG. 18 illustrating delivery of fluid from the irrigation pump,
as controlled by the controller, to the hydrophilic insert within
the interior chamber of the distal portion of the device;
[0049] FIG. 24 is a perspective view of a detachable mount for
holding a temperature probe (or any other separate monitoring
device) at a desired position relative to the distal portion of the
ablation device for the collection of temperature data during an RF
ablation procedure; and
[0050] FIG. 25 is a plan view of the detachable mount holding the
temperature probe relative to the distal portion of the ablation
device.
[0051] For a thorough understanding of the present disclosure,
reference should be made to the following detailed description,
including the appended claims, in connection with the
above-described drawings. Although the present disclosure is
described in connection with exemplary embodiments, the disclosure
is not intended to be limited to the specific forms set forth
herein. It is understood that various omissions and substitutions
of equivalents are contemplated as circumstances may suggest or
render expedient.
DETAILED DESCRIPTION
[0052] By way of overview, the present disclosure is generally
directed to a tissue ablation system including an ablation device
to be delivered to a tissue cavity and configured to emit energy in
a desired shape or pattern so as to deliver treatment for the
ablation and destruction of a targeted portion of marginal tissue
around the tissue cavity.
[0053] A tissue ablation system consistent with the present
disclosure may be well suited for treating hollow body cavities,
such as irregularly-shaped cavities in breast tissue created by a
lumpectomy procedure. For example, once a tumor has been removed, a
tissue cavity remains. The tissue surrounding this cavity is the
location within a patient where a reoccurrence of the tumor may
most likely occur. Consequently, after a tumor has been removed, it
is desirable to destroy the surrounding tissue (also referred
herein as the "margin tissue" or "marginal tissue").
[0054] The tissue ablation system of the present disclosure can be
used during an ablation procedure to destroy the thin rim of
marginal tissue around the cavity in a targeted manner. In
particular, the present disclosure is generally directed to a
cavitary tissue ablation system including an ablation device to be
delivered into a tissue cavity and configured to emit non-ionizing
radiation, such as radiofrequency (RF) energy, in a desired shape
or pattern so as to deliver treatment for the ablation and
destruction of a targeted portion of marginal tissue around the
tissue cavity.
[0055] The system of the present invention is configured to provide
a user with custom ablation shaping, which includes the creation of
custom, user-defined ablation geometries depending on the target
site. In particular, rather than simply providing a universal RF
ablation shape or profile, the system allows for a user to
customize the emission of energy to a targeted portion of marginal
tissue within the cavity, which is particularly useful in instances
in which non-uniform ablation is desired. The customized emission
of energy may include a specific shape or geometry of emission, as
well as time and depth of penetration of RF energy.
[0056] The devices, systems, and methods of the present disclosure
can help to ensure that all microscopic disease in the local
environment has been treated. This is especially true in the
treatment of tumors that have a tendency to recur. Furthermore, by
providing custom ablating shaping, in which the single ablation
device may provide numerous RF energy emission shapes or profiles,
the system of the present invention allows for non-uniform ablation
to occur. This is particularly useful in controlling ablation shape
so as to avoid vital organs and any critical internal/external
structures (e.g., bone, muscle, skin) in close proximity to the
tumor site, while ensuring that residual marginal tissue within the
local environment has been treated.
[0057] The tissue ablation device of the present invention
generally includes a probe including an elongated shaft configured
as a handle and adapted for manual manipulation and a nonconductive
distal portion coupled to the shaft. The nonconductive distal
portion includes an electrode array positioned along an external
surface thereof. The distal portion, including the electrode array,
can be delivered to and maneuvered within a tissue cavity (e.g.,
formed from tumor removal) and configured to ablate marginal tissue
(via RF energy) immediately surrounding the tissue cavity in order
to minimize recurrence of the tumor. The ablation device of the
present invention is further configured to provide a user with
custom ablation shaping, which includes the creation of custom,
user-defined ablation geometries or profiles.
[0058] It should be noted the devices of the present disclosure are
not limited to such post-surgical treatments and, as used herein,
the phrase "body cavity" may include non-surgically created
cavities, such as natural body cavities and passages, such as the
ureter (e.g. for prostate treatment), the uterus (e.g. for uterine
ablation or fibroid treatment), fallopian tubes (e.g. for
sterilization), and the like.
[0059] FIG. 1 is a schematic illustration of an ablation system 10
for providing targeted ablation of marginal tissue during a tumor
removal procedure in a patient 12. The ablation system 10 generally
includes an ablation device 14, which includes a probe having a
distal tip or portion 16 and an elongated catheter shaft 17 to
which the distal tip 16 is connected. The catheter shaft 17 may
generally include a nonconductive elongated member including a
fluid delivery lumen. The ablation device 14 may further be coupled
to a device controller 18 and an ablation generator 20 over an
electrical connection (electrical line 34 shown in FIG. 2), and an
irrigation pump or drip 22 over a fluid connection (fluid line 38
shown in FIG. 2).
[0060] As will be described in greater detail herein, the device
controller 18 may further include a custom ablation shaping (CAS)
system 100 configured to provide a user with custom ablation
shaping, which includes the creation of custom, user-defined
ablation geometries or profiles from the ablation device 14. In
some cases, the device controller 18 may be housed within the
ablation device 14. The ablation generator 20 may also connected to
a return electrode 15 that is attached to the skin of the patient
12.
[0061] As will be described in greater detail herein, during an
ablation treatment, the ablation generator 20 may generally provide
RF energy (e.g., electrical energy in the radiofrequency (RF) range
(e.g., 350-800 kHz)) to an electrode array of the ablation device
14, as contollered by the device controller 18. At the same time,
saline may also be released from the distal tip 16. The RF energy
travels through the blood and tissue of the patient 12 to the
return electrode 112 and, in the process, ablates the region(s) of
tissues adjacent to portions of the electrode array that have been
activated.
[0062] FIG. 2 is a perspective view of the distal portion or tip 16
of the ablation device 14. The distal tip 16 may include a neck
portion 24 and a generally spheroid body 26 extending distally from
the neck 24. It should be noted that, in some embodiments, the
spheroid body 26 may be configured to transition between a
collapsed state and an expanded state. For example, the spheroid
body 26 may be collapsible to a delivery configuration having a
reduced size (e.g., equatorial diameter) relative to the deployed
configuration size (e.g., equatorial diameter) of the spheroid body
26. In some examples, the spheroid body 26 is a generally
prolate-spheroid during delivery and transitions to a spheroid
shape during deployment. In other embodiments, the spheroid body 26
may be rigid, and thus may maintain a default shape.
[0063] In some examples, the spheroid body 26 includes a
non-conductive material (e.g., a polyamide) as a layer on at least
a portion of an internal surface, an external surface, or both an
external and internal surface. In other examples, the spheroid body
26 is formed from a non-conductive material. Additionally or
alternatively, the spheroid body 26 material can include an
elastomeric material or a shape memory material.
[0064] In some examples, the spheroid body 26 has a diameter (e.g.,
an equatorial diameter) of about 80 mm or less. In certain
implementations, the spheroid body 26 of the distal tip, in a
deployed configuration, has an equatorial diameter of 2.0 mm to 60
mm (e.g., 5 mm, 10 mm, 12 mm, 16 mm, 25 mm, 30 mm, 35 mm, 40 mm, 50
mm, and 60 mm). Based on the surgical procedure, the collapsibility
of the spheroid body 28 can enable the distal tip to be delivered
using standard sheaths (e.g., an 8F introducer sheath).
[0065] The distal tip 16 of the ablation device 14 further includes
an electrode array positioned thereon. The electrode array includes
at least one conductive member 28. As illustrated in the figures,
the electrode array includes at least eight conductive members 28.
Accordingly, the electrode array may include a plurality of
conductive members 28. The plurality of conductive members 28
extend within the distal tip 16, through a channel 32 and along an
external surface of the spheroid body 26. The conductive members 28
extend along the longitudinal length of the distal tip 16 and are
radially spaced apart (e.g., equidistantly spaced apart) from each
other. These conductive members transmit RF energy from the
ablation generator and can be formed of any suitable conductive
material (e.g., a metal such as stainless steel, nitinol, or
aluminum). In some examples, the conductive members 28 are metal
wires. Accordingly, for ease of description, the conductive
member(s) will be referred to hereinafter as "conductive wire(s)
28".
[0066] As illustrated, one or more of the conductive wires 28 can
be electrically isolated from one or more of the remaining
conductive wires 28. This electrical isolation enables various
operation modes for the ablation device 14. For example, ablation
energy may be supplied to one or more conductive wires 28 in a
bipolar mode, a unipolar mode, or a combination bipolar and
unipolar mode. In the unipolar mode, ablation energy is delivered
between one or more conductive wires 28 on the ablation device 14
and the return electrode 12, as described with reference to FIG. 1.
In bipolar mode, energy is delivered between at least two of the
conductive wires 28, while at least one conductive wire 28 remains
neutral. In other words, at least, one conductive wire functions as
a grounded conductive wire (e.g., electrode) by not delivering
energy over at least one conductive wire 28.
[0067] The electrode array may further include one or more
stabilizing members 30 configured to provide support for the
plurality of conductive wires 28. The one or more stabilizing
member 30 generally extend along a surface (e.g., external or
internal) of the distal tip 16 so as to circumscribe the spheroid
body 26. The stabilizing members 30 can, in some examples,
electrically connect to one or more conductive wires 28. In other
examples, the stabilizing members 30 are non-conductive. The
stabilizing members 30 can be formed of a suitably stiff material
(e.g., metal such as stainless steel, nitinol, or aluminum). In
some implementations, the stabilizing members 30 can be integral
with a portion of the spheroid body 26 (e.g., as a rib). While, the
distal tip 16 is generally shown with one or more stabilizing
members, in some implementations, the distal tip 16 is free of
stabilizing members.
[0068] As shown, the distal tip 16 may be coupled to the ablation
generator 20 and/or irrigation pump 22 via an electrical line 34
and a fluid line 38, respectively. Each of the electrical line 34
and fluid line 38 may include an adaptor end 36, 40 configured to
couple the associated lines with a respective interface on the
ablation generator 20 and irrigation pump 22. In some examples, the
ablation device 14 may further include a user switch or interface
19 serving as the device controller 18 and in electrical
communication with the ablation generator 20 and the ablation
device 14. The switch 19 can provide a user with various options
with respect to controlling the ablation output of the device 14,
as will be described in greater detail herein. For example, the
switch 19, which may serve as the device controller 18, may include
a CAS system 100 configured to provide custom ablation shaping
controls for a user to create custom, user-defined ablation
geometries or profiles, as well as control particular ablation
parameters, such as control of timing of the emission (e.g., length
of time, intervals, etc.) as well as the depth of RF energy
penetration. In some embodiments, the switch 19 may be configured
to control energy delivery from the ablation generator 20 so that
one or more individual conductive wires, or a designated
combination of conductive wires, are energized for a pre-selected,
or desired, duration.
[0069] FIGS. 3A, 3B, and 3C are perspective views of the distal tip
16 of FIG. 2 in greater detail. As shown in FIGS. 2 and 3A-3C, the
conductive wires 28 extend through a lumen 42 within the distal tip
16. For example, each of the conductive wires 28 enters the lumen
42 of the neck 27 and extends through the distal tip portion 16
before exiting the distal tip through either a center channel 32 at
a distal most portion of the distal tip or one of a plurality of
proximal ports 44. In some examples, a plurality of distal ports 46
extending through a wall of the distal tip 16 is positioned around
the channel 32. A plurality of proximal ports 44 can also extend
through a wall of the distal tip 16. These proximal ports 44 can be
positioned around the distal tip 16 in close proximity (e.g.,
within at least 5 mm, within at least 3 mm, within at least 1 mm,
within 0.5 mm, within 0.4 mm, or within 0.2 mm) to the junction
between the spheroidal body 26 and the neck 24 of the distal tip
16. In some cases, the number of proximal ports 44 and distal ports
46 is equal to the number of conductive wires 28.
[0070] In some examples, each conductive wire 28 can extend through
a different distal port 46, which allows the conductive wires 28 to
remain electrically isolated from one another. In other examples,
one or more conductive wires can extend through the same distal
port 46.
[0071] Upon passing through a distal port 46, each conductive wire
28 can extend along an external surface of the distal tip 16. In
some examples, the length of the conductive wire 28 extending along
the external surface is at least 20% (e.g., at least, 50%, 60%,
75%, 85%, 90%, or 99%) of the length of the spheroid body 26. The
conductive wire 28 can then re-enter the lumen 42 of the distal tip
16 through a corresponding proximal port 44. For example, as shown
in FIG. 3C, conductive wire 28(1) passes through distal port 46(1),
extends along a length of the external surface of the distal tip
16, and passes through an associated proximal port 44(1) into the
lumen 42 of the distal tip 16, while conductive wire 28(2) is
electrically isolated from conductive wire 28(1) in that it passes
through associated proximal and distal ports 44(2), 46(2),
respectively.
[0072] In some examples, each conductive wire 28 can extend through
a different associated proximal port 44, which allows the
conductive wires 28 to remain electrically isolated from one
another. In other examples, one or more conductive wires can extend
through the same proximal port. Yet still, as will be described in
greater detail herein, particularly with reference to the device
14a illustrated in FIGS. 21A-21B and 22A-22B, an individual
conductive wire can extend through multiple proximal and distal
ports.
[0073] FIG. 4 is a block diagram illustrating the custom ablation
shaping (CAS) system 100 of the device controller 18. As previously
described herein, the electrode array is composed of a plurality of
conductive wires 28 electrically isolated and independent from one
another. This design allows for each conductive wire 28 to receive
energy in the form of electrical current from the ablation
generator 20 and emit RF energy in response. The device controller
18 is configured to selectively control the supply of electrical
current to each of the conductive wires via the CAS system 100.
[0074] The CAS system 100 includes one or more of the following: a
user interface 102; an ablation tracking interface subsystem 104;
an ablation mapping subsystem 106; an ablation geometry shaping
subsystem 108; an electrode connection multiplier controller 110;
and an electrode connection multiplexer controller 112. It should
be noted that the dashed connections (between the user interface
102 and electrode connection multiplier controller 110 and the
electrode connection multiplexer controller 112) indicate
fail-safes and out-of-band control lines not used, or intended for
use, during normal operation. However, in the event that one or
more of the components fail to operate as intended, the user may
override such components so as to directly control activation of
one or more conductive wires 28.
[0075] As previously described, the specific design of the
electrode array (e.g., plurality of conductive wires electrically
isolated and independent from one another) allows for each
conductive wire to receive energy in the form of electrical current
from the ablation generator 20 and emit RF energy in response. In
particular, the device controller 18 allows for individual
conductive wires, or a designated combination of conductive wires,
to be controlled so as to result in the activation (e.g., emission
of RF energy) of corresponding portions of the electrode array.
[0076] In some embodiments, the device controller 18, specifically
by way of the CAS system 100, provides a user with the ability to
manually control the supply of electrical current to each of the
conductive wires. More specifically, the user interface 102 may
provide a user with the ability to create custom ablation shapes or
patterns, or further manipulate ablation parameters (e.g., timing
and intensity) via an interactive interface, which may be in the
form of a graphical user interface (GUI) provided on a display of
the device controller 18 or switch 19. Accordingly, as will be
described in greater detail herein (shown in FIGS. 5, 6A-6B, and
7A-7B), the CAS system 100 may allow a user to manually control
emission from the electrode array and customize the ablation shape
or geometry as they see fit.
[0077] In other embodiments, the CAS system 100 may be configured
to automatically provide custom ablation shaping in addition, or
alternatively, to manual input from a user. For example, the device
controller 18 may be configured to provide ablation status mapping
based on real-time data collection (e.g., temperature and
conductivity measurements (impedance measurements) from one or more
of the conductive wires) so as to provide an estimation of the
state of the tissue during an RF ablation procedure. The CAS system
100 is configured to generate ablation status mapping of a target
tissue based, at least in part, on characterizing temporal changes
in conductivity of a target tissue during ablation and correlating
such changes with temperature and cell viability. The ablation
status mapping may then be combined with an electrode activation
algorithm for the assignment of parameters for selective electrode
activation for ablation shaping. Accordingly, the automatic custom
ablation shaping feature of the present invention allows for
spatial resolution of the ablation mapping and shaping systems to
occur in vitro and further determine the depths from the electrode
which the mapping/sensing system can make reliable estimations.
Thus, the system can compensate ablation progression during control
parameter calculations so as to provide more accurate ablation of a
target tissue while avoiding any vital organs or critical
internal/external structures in close proximity to the target
tissue.
[0078] In order to achieve the capability of ablation status
mapping, the CAS system 100 is configured to collect data for a
machine learning model and then use the model to map ablation
status in real time. The data collected includes, but is not
limited to, temperature measurements, conductivity or impedance
measurements, and photonic properties of the target tissue. By
measuring time and the change in impedance (real or complex),
temperature, and/or photonic properties of the target tissue, the
CAS system 100 is configured to determine the ablation shape or
geometry (energy emission from electrode array) in real-, or
near-real-, time.
[0079] Since each conductive wire in the electrode array is
electrically independent, each conductive wire can be connected in
a fashion that allows for impedance measurements using bipolar
impedance measurement circuits. For example, the conductive wires
can be configured in such a fashion that tetrapolar or guarded
tetrapolar electrode configurations can be used. For instance, one
pair of conductive wires could function as the current driver and
the current return, while another pair of conductive wires could
function as a voltage measurement pair. The dispersive ground pads
15 can also function as current return and voltage references.
Their placement dictate the current paths and thus having multiple
references can also benefit by providing additional paths for
determining the ablation status of the tissue.
[0080] The electrode connection multiplexer controller 112 is
configured to collect the data in the form of local impedances
(impedances between conductive wires on the distal tip) and global
impedances (impedances between conductive wires and global
dispersive return 15) and further transmit such data to the
ablation mapping subsystem 106. A Kelvin electrode configuration
driven with 500 .mu.A at 200 kHz (for filtering from the 470 kHz RF
signal) may be used in order to measure these impedances.
[0081] The ablation mapping subsystem 106 is configured to analyze
the impedance data with time elapsed in order to form a judgment of
the ablation status of certain parts of the entire ablation volume.
In particular, the ablation mapping subsystem 106 may include
custom, proprietary, known and/or after-developed analysis code (or
instruction sets), hardware, and/or firmware that are generally
well-defined and operable to receive one or more sets of data and
estimate an ablation status of local target tissue sub volumes
based on analysis of such data. Thus, the ablation mapping
subsystem 106 may utilize a specific input model in order to output
an ablation status integer for any sub volume of the ablation
volume. The input model is as follows:
(t,s,init_local_Z[ ],init_global_Z[ ],current_local_Z[
],current_global_Z[ ],x,y,z).fwdarw.AblationStatus
[0082] where `t` indicates time in seconds, `s` indicates the size
of the applicator (diameter, area, volume, etc. of the distal tip),
`Z` indicates impedance, `H` indicates arrays with length of the
number of conductive wires, and `x,y,z` are the coordinates of the
sub volume.
[0083] As in the input model provided above, each sub volume the
ablation map may include five possible statuses: "0" indicating no
ablation occurring, "1" indicating that heating is occurring, "2"
indicating that instantaneous ablation or coagulation has begun
(the tissue has reached a temperature of 60.degree. C.), "3"
indicating that ablation has occurred, and "4" indicating that
desiccation (vaporization) is occurring. In order to develop the
classification model, benchtop ablations are performed where the
following training data is collected: time, init_local_Z[ ],
init_global_Z[ ], current_local_Z[ ], current_global_Z[ ], and for
a set of radii (0.25, 0.5, 0.75, 1.0, 1.25, 1.5 cm) surrounding the
applicator, the exact temperature, which translates to the ablation
status (0 for initial temperature, 1 for .gtoreq.40.degree. C., 2
for .gtoreq.50.degree. C., 3 for .gtoreq.60.degree. C., 4 for
.gtoreq.100.degree. C.). This method of ablation mapping is also
designed to be mostly heterogeneity-invariant, since local
impedances are inputs into the model, which treat the heterogeneous
tissues as different tissue types present.
[0084] In order to obtain reference tissue ablation parameters, the
training data may then be input into multiple supervised machine
learning algorithms, where the most accurate classifier will be
used for the real-time system. Training data may be collected
within ex vivo bovine and porcine liver blocks of 10 cm by 10 cm by
10 cm. The tissue can be placed in a saline bath such that the
global ground is simulated as far-field to prevent optimistic
global impedance measurements. Verifications on the classifier will
be performed after the model is learned to ensure success criteria,
including controls with and without RF energy applied.
[0085] The target endpoint is 90% accuracy (with zero false ablated
statuses) of ablation status mapping with 1.0 mm of spatial sub
volume resolution for the local field (.ltoreq.1.0 cm depth from
applicator surface). Additional success criteria may include the
accuracy of ablation status mapping up to 3.0 mm sub volume
resolution into the sub global field (1.0-2.0 cm depth from
applicator surface).
[0086] If the classifier fails to classify based only on initial
and changes in impedance, then an additional parameter, the
estimated local tissue conductivity, will be added to the model.
The estimated conductivity is covered within the model by the
initial and early-time impedances, but a more explicit variable may
be required. If the target endpoint spatial resolutions failed to
be realized, then the electrodes will be increased in number to
increase density for higher spatial resolution.
[0087] The ablation geometry shaping subsystem 108 is configured to
receive output data from the ablation mapping subsystem 106,
specifically ablation status mapping data via the ablation tracking
interface subsystem 104, and determine a specific ablation shape or
geometry to output (e.g., identify specific conductive wires or
combination of conductive wires to apply power to and the specific
parameters) in order to achieve the desired custom ablation shape
based on the ablation status mapping. In particular, the ablation
geometry shaping subsystem 108 may rely on an electrode activation
algorithm necessary to operate the network of solid-state relays
(also known as a crossbar) that connect the conductive wires to the
radiofrequency power generator 20. The ablation geometry shaping
subsystem 108 may generate ablation shape data based on processing
of the ablation status mapping data via the electrode activation
algorithm.
[0088] The ablation geometry shaping subsystem 108 may then
transmit ablation shape data to the electrode connection
multiplexer controller 112 for activation of specific conductive
wires, or combinations of conductive wires, so as to achieve the
desired ablation shape. For example, the electrode connection
multiplier controller 110 may be configured to physically operate
solid-state relays on the electrode connection multiplexer (the
electrode-switching/power-switching circuit), connecting the
electrodes needed to RF power. By time-division multiplexing,
different conductive wires in a manner similar to pulse width
modulation (PWM), where the conductive wires are connected to power
for a specified duration and then disconnected in a repeated
pattern. Time-multiplexing may be especially important for deeper
ablations that are geometrically between multiple conductive wires,
in which the theoretical circuit relies on heat transfer to nearby
(i.e., not currently electrically-conducting) tissues and only the
concentration of heat in the desired zone due to the combined
efforts of the conductive wires activating in the multiplexed
fashion.
[0089] The ablation mapping subsystem 106 and ablation geometry
shaping system 108 may be configured to continuously operate during
a procedure so as to provide up-to-date information which may
further improve the accuracy and safety of the ablation procedure.
For example, ablation status mapping data may be continuously
generated and fed into the ablation geometry shaping system 108 so
as to continuously generate ablation shaping data, which may be
used to either validate the current ablation energy applied, or to
update or correct the ablation shape (i.e., indicate where to
continue ablation or when to stop ablation). It should further be
noted that ablation mapping status can be displayed to a user using
a 3D visualization, which can be controlled by the user interface
102 (e.g., touchscreen or the like) similar to a 3D map
application. Each layer of tissue may be displayed as being
somewhat transparent so as to allow for the operator to see which
regions are ablated and which are not.
[0090] As previously described, the device controller 18 may be
configured to be operated manually, such that a user (e.g., surgeon
or operator) may input desired ablation shape or pattern and
associated parameters. FIG. 5 is a top view of one embodiment of
device controller 19 configured for individually controlling
operational modes of each of the plurality of conductive wires of
the electrode array of the ablation device tip. The controller 19
may provide selectable inputs 50(1)-50(8) in which a user may turn
individual conductive wires, or one or more combinations of
conductive wires, on and off, thereby allowing a user to control an
ablation shape or geometry. As shown, the selectable inputs
50(1)-50(8) may correspond to the eight individual conductive wires
28(1)-28(8) of the distal tip 16 (see FIGS. 6A-6B and 7A-7B).
Accordingly, activation of any one of the selectable inputs 50 may
result in the activation of corresponding conductive wires 28.
[0091] FIG. 6A is a top view of the device controller 19 with
inputs 50 in a first mode and FIG. 6B is a front view of the
ablation device tip illustrating the electrode array operating in
the first mode. As shown, input 50(1) is selected and, in turn, the
corresponding conductive wire 28(1) is activated (current supplied
thereto and RF energy emitted). Accordingly, the electrode array
may be configured to operate in a monopolar mode in which
individual conductive wires may be activated.
[0092] FIG. 7A is a top view of the device controller 19 with
inputs 50 in a second mode and FIG. 7B is a front view of the
ablation device tip illustrating the electrode array operating in
the second mode. As shown, inputs 50(1)-50(4) are selected and, in
turn, the corresponding conductive wires 28(1)-28(4) are activated,
such that the electrode array may operate in a bipolar mode, where
pairs of conductive wires 28(1)-28(2) and 28(3)-28(4) are
activated.
[0093] FIGS. 8A-8E are perspective views of a distal tip 16 of the
ablation device of FIG. 1 illustrating various electrode array
configurations. In addition, while the conductive wires 28 have
been described as extending along an external surface of the distal
tip 16 in a direction that is parallel to the longitudinal axis of
the device (as shown in a longitudinal configuration of conductive
wires 28a in FIG. 8A), other configurations are possible. For
example, one or more conductive wires 28b could extend along the
external surface of the distal tip 16 in a direction that is
perpendicular to the longitudinal axis of the device (as shown in a
circumferential configuration in FIG. 8B). In other examples, one
or more conductive wires 28c can extend from along the external
surface of the distal tip 16 at an angle (e.g., non-parallel to the
longitudinal axis of the device), as shown in an angled
configuration in FIG. 8C. One or more conductive wires 28d, 28e,
and 28f can also form a pattern along the external surface in which
the conductive wires extend in various directions, as shown in a
combined configuration in FIG. 8D. Additionally or alternatively,
one or more conductive wires 28g can extend a reduced length of the
external surface an alternative configuration in FIG. 8E.
[0094] While various conductive wires 28 have generally been
described such that individual conductive members are energized or
that the desired combination of conductive members is energized for
a pre-selected or desired duration, in some cases, the desired
combination of conductive members can be based on desired contact
region of the distal tip 16. FIG. 9 is a side view of the distal
tip 16 of the ablation device 14 of FIG. 1 including several
clinical axes or sides. Each clinical axis or side includes one or
more independently connected electrodes, which enables differential
function and current independent drives and/or measurements. For
example, referring to FIG. 9, the distal tip 16 can be divided into
clinical axes or sides 52, 53, 54, 55, 56, and 57 (not shown). In
other words, the distal tip 16 may include six clinical axes or
sides of the distal portion (e.g, four sides or quadrants around
spheroid body 54, 55, 56, and 57, and a bottom axis/side 52, and a
top axis/side 53).
[0095] FIGS. 10-10D are side and perspective views of the distal
tip of the application device illustrating the different clinical
axes or sides of FIG. 9. As shown in FIGS. 10A-10D, each clinical
axis can include multiple independently connected conductive wires.
For example, clinical axis/side 52 can include three independently
connected conductive wires 58, clinical axis/side 53 can include
three independently connected conductive wires 60, clinical
axis/side 54 can include three independently controlled conductive
wires 62, clinical axis/side 55 can include three independently
connected conductive wires 64, clinical axis/side 56 can include
three independently controlled conductive wires 66, and clinical
axis/side 57 can include three independently controlled conductive
wires 68. The independently connected conductive wires within each
clinical axis or side allows for differential function and
independent energy delivery and/or measurements. While FIGS.
10A-10D generally show three conductive wires for each clinical
axis or side, other combinations are possible. For example, each of
the clinical axes or sides can include a combination of conductive
wires ranging from one conductive wire to ten or more conductive
members.
[0096] FIG. 11A is a perspective view of a distal tip 16 of an
application device consistent with the present disclosure
illustrating a nonconductive cap member 70 coupled to the distal
tip 16 and configured to block emission of energy from at least one
of the conductive wires 28. The nonconductive cap member 70 may be
selectively positionable over one or more portions of the electrode
array so as to block emission of energy therefrom while permitting
the emission of energy from remaining portions of the electrode
array. Accordingly, the nonconductive cap member 70 allows for the
ablation of a target tissue in a specific pattern, as dictated by
the physical coverage of the cap member 70.
[0097] As shown in FIGS. 11A and 11B, the cap member 70 may be
positioned over at least three of the eight conductive wires
(covering conductive wires 28(6)-28(8)). Thus, by blocking energy
emission from wires 28(6)-28(8), the remaining conductive wires
(28(1)-28(5) remain able to emit energy in a particular ablation
shape or geometry. Accordingly, the nonconductive cap member 70 may
be selectively positionable over one or more of the plurality of
conductive wires so as to block emission of energy from such wires
and preventing emission from the corresponding portion of the
electrode array, while permitting the remaining wires to emit
energy. As illustrated in FIG. 11C, the cap member 70 is configured
to be selectively positionable relative to the conductive wires 28.
In particular, the cap member 70 may be rotationally coupled to the
distal tip 16, such that a user may simply use a controller, or
other means, for rotating the cap member 70 about the spheroid body
26, as indicated by arrow 72, so as to manually cover a specific
wires 28 so as to select a desired ablation shape or geometry.
[0098] In some embodiments, the nonconductive cap member 70 may
have a predefined shaped or size, such that the cap member 70 has a
fixed area of coverage (e.g., is limited covering a specific number
of conductive wires or number of electrode array portions). For
example, the cap member 70 may be shaped or sized to cover a single
quadrant of a spheroid distal portion, such that, at any given
time, three out of four quadrants will remain uncovered and thus
emit RF energy in a corresponding pattern. In other embodiments,
the nonconductive cap member 70 may be shaped or sized to cover
more than one quadrant (e.g., at least two quadrants, at least
three quadrants, etc.).
[0099] FIG. 12 is an exploded perspective view of an ablation
device 14 consistent with the present disclosure. In some
implementations, the ablation device 14, specifically the distal
tip 16, may be formed from two or more pieces (tip halves 16a and
16b) configured to be coupled to one another to form the unitary
distal tip 16. Each half 16a and 16b includes cooperating neck
portions 24a, 24b and spheroid bodies 26a, 26b, as well as a cap 76
to be coupled to both halves 16a and 16b so as to fully enclose the
interior of the distal tip 16. As further illustrated, an
electrical line 34 may be provided for coupling the conductive
wires 28 to the controller 18 and ablation generator 20 and a fluid
line 38 may be provided for providing a fluid connection between
the irrigation pump or drip 22 to the distal tip 16 so as to
provide a conductive fluid (e.g., saline) to the tip 16. The
electrical line 34 and/or the fluid delivery line 38 can be
supported by a stabilizing element 84 within the device lumen. In
some cases, the stabilizing element 84 may be integral with the
neck 24 of the distal tip 16.
[0100] As previously described, conductive members 28 extend
through a first port (e.g., the distal port 44), run along an
external surface of the spheroid body 26 (e.g. within the groove
74) before re-entering the lumen of the distal tip 16 through
another port (e.g., the proximal port 46). As will be described in
greater detail herein, a conductive fluid, such as saline, may be
provided to the distal tip 16 via the fluid line 38, wherein the
saline may be distributed through the ports (e.g., to the distal
ports 44, the proximal ports 46, and/or medial ports 45). The
saline weeping through the ports and to an outer surface of the
distal tip 16 is able to carry electrical current from electrode
array, such that energy is transmitted from the electrode array to
the tissue by way of the saline weeping from the ports, thereby
creating a virtual electrode. Accordingly, upon the fluid weeping
through the ports, a pool or thin film of fluid is formed on the
exterior surface of the distal tip 16 and is configured to ablate
surrounding tissue via the electrical current carried from the
electrode array.
[0101] FIG. 13A is a front view of one embodiment of a distal tip
16 of the ablation device 14 of FIG. 12 illustrating one or more
chambers formed within the distal tip 16 and FIG. 13B is a
sectional view of distal tip 16 taken along lines A-A. The distal
tip 16 may include at least two internal chambers configured to
receive and retain fluid therein as provided by the fluid line 38.
As shown in FIG. 13A, the distal tip 16 is partioned into quadrants
such that it includes four separate chambers 86(1)-86(4). FIG. 13B
illustrates at least two of the internal chambers 86(3) and 86(4).
As shown, each chamber 86 generally includes an inlet port 88
configured to receive the fluid from the fluid delivery line 38 and
further allow the fluid to flow into the corresponding chamber 86.
Each chamber 86 further includes one or more perforations in a wall
of the chamber. As shown in FIG. 13B, the one or more perforations
may include ports 44-46. However, in some embodiments, each chamber
may include additional perforations (such as perforations 98 shown
in FIG. 15). The ports, or perforations, may generally be
configured to allow fluid to pass therethrough, or weep, from the
chamber 86 to an external surface of the spheroid body 26.
[0102] As previously described, the ablation device further
includes an electrode array positioned along an external surface of
the distal portion. Upon positioning the distal portion within a
target site (e.g., tissue cavity to be ablated), the electrode
array can be activated. The fluid weeping through the perforations
of the internal chambers and to the outer surface of the spheroid
body of the distal portion is a conductive fluid (e.g., saline) and
thus able to carry electrical current from electrode array, such
that energy is transmitted from the electrode array to the tissue
by way of the fluid weeping from the perforations, thereby creating
a virtual electrode.
[0103] The ablation device 14 may further include includes at least
one flow control member associated with each chamber 86 so as to
modify fluid flow into or out of each chamber 86 by way of a user
manipulating a controller 90. The at least one flow control member
is configured to transition between open, closed, and intermediate
positions so as to ultimately control the passage of fluid through
the one or more perforations to the external surface of the
spheroid body, thereby effectively controlling the ablation pattern
or shape. In particular, in the event that a flow control member
associated with a first internal chamber is completely closed,
thereby preventing flow of fluid through the perforations of the
first internal chamber, ablation is prevented from occurring along
an external surface of the spheroid body associated with the first
internal chamber. Alternatively, in the event that the flow control
member associated with the first internal chamber is completely
opened, thereby allowing flow weeping of fluid through the
perforations, ablation is allowed to occur along the external
surface of the spheroid body associated with the first internal
chamber. Accordingly, a user may manually manipulate each flow
control member of the internal chambers so as to control the
ablation shape or geometry.
[0104] As shown in FIG. 14A, the flow control member may include a
contractable/expandable aperture 92 essentially serving as the
inlet port for each chamber 86. FIG. 14A is a rear view of the
distal tip 16, in a direction from the neck 24 towards the spheroid
body 26, providing a view into the lumen 42 of the distal tip 16.
As shown, each internal chamber 86(1)-86(4) has an associated
contractable/expandable aperture 92(1)-92(4) configured to control
the flow rate of fluid into the associated chamber 86 so as to
modify fluid flow out of the ports or perforations of the chamber
86. The contractable/expandable apertures 92(1)-92(4) may generally
resemble a lens iris (commonly found in cameras) configured to
transition between fully open, fully closed, and intermediate
positions there between.
[0105] FIG. 14B illustrates an exemplary control member 90 coupled
to a contractable/expandable aperture 92 and configured to control
contraction/expansion of the aperture 92. As shown, a user may be
able to manipulate the control member 90 so as to transition the
aperture 92 between fully open and fully closed positions. Each
aperture 92 may include an associated control member 90, such that
a user may be able to independently control the contract/expansion
of the individual apertures 92 separately from one another to
customize the ablation shape or geometry.
[0106] As shown in FIG. 15, the flow control member may include a
moveable plunger 94 positioned within each chamber 86 and
configured to move relative to the inlet port 88 so as to control
of the passage of fluid into the inlet port and subsequently
control weeping of fluid through the ports or perforations. As
shown, each plunger 94 may be coupled a control member 90 (e.g.,
button, switch, etc.) configured to move in a direction relative to
the inlet port 88, as indicated by arrow 96. A user may manipulate
the control member 90 to move the plunger between a fully open
position, as shown with respect to the inlet port of chamber 86(4),
and a fully closed position, in which the plunger 94 is engaged
with the inlet port 88, as shown with respect to chamber 86(3), so
as to prevent fluid flow into the 86(3), thus modifying flow
passage through the perforations 98.
[0107] Each of the internal chambers 86 may further include a ledge
or shelf 97 provided therein, wherein the ledge 97 is positioned so
as to improve uniformity of fluid distribution to one or more of
the perforations, most notably the perforations most proximate to
the neck 24 (e.g., perforations 98(1)-98(3). In some instances,
fluid within a chamber 86 may have the tendency to pool near a
bottom of the chamber 86 depending on the orientation of the
spheroid body 26 due to gravity. Thus, those perforations that are
closest to the neck 24 will likely not receive fluid to pass
therethrough, which may lead to inaccurate or incomplete ablation,
as the fluid is not evenly distributed along the external surface
of the body 26. The ledge 97 is positioned in such a manner that
fluid may first accumulate within a portion of the ledge 97 and
allow the perforations 98(1)-98(3) to fill with fluid prior to the
remaining perforations 98(4) and 98(5), which will normally fill
with fluid, thereby ensuring uniform distribution of fluid
weeping.
[0108] FIGS. 16 and 17 are perspective and exploded perspective
views, respectively, of another one embodiment of a device
controller 200 consistent with the present disclosure. Similar to
user switch or interface 19, the device controller 200 may serve as
the device controller 18 and is in electrical communication with
the ablation generator 20 as well as the irrigation pump/drip 22.
Accordingly, the controller 200 can provide a user with various
options with respect to controlling the ablation output of an
ablation device consistent with the present disclosure,
specifically providing a surgeon with the functions provided by
switch 19 and/or the controller 18 having control of the CAS system
100. For example, controller 200 may include the CAS system 100
configured to provide custom ablation shaping controls for a user
to create custom, user-defined ablation geometries or profiles, as
well as control particular ablation parameters, such as control of
timing of the emission (e.g., length of time, intervals, etc.) as
well as the depth of RF energy penetration.
[0109] As shown, the controller 200 may include a first halve or
shell 202a and a second halve or shell 202b for housing a PC 204
within, the PC board 204 comprising circuitry and hardware for
controlling various parameters of the device 14 during an ablation
procedure. The controller 200 further includes a display 206, such
as an LCD or LED display for providing a visual representation of
one or more parameters associated with the device 14, including,
but not limited to, device status (e.g., power on/off, ablation
on/off, fluid delivery on/off) as well as one or more parameters
associated with the RF ablation (e.g., energy output, elapsed time,
timer, temperature, conductivity, etc.). The controller 200 may
further include a top membrane 208 affixed over the PC board 204
and configured to provide user input (by way of buttons or other
controls) with which a user (e.g., surgeon or medical professional)
may interact with a user interface provided on the display 206. The
controller 200 may be configured to control at least the amount of
electrical current applied to one or more of the conductive wires
28 from the ablation generator 20 and the amount of fluid to be
delivered to the device 14 from the irrigation pump/drip 22.
[0110] FIG. 18 is an exploded perspective view of another
embodiment of an ablation device 14a consistent with the present
disclosure. The device 14a is similarly configured as device 14
illustrated in FIG. 12, and includes similar elements. For example,
the device 14a includes the distal tip 16 formed from two or more
pieces (tip halves 16a and 16b) configured to be coupled to one
another to form the unitary distal tip 16. Each half 16a and 16b
includes cooperating neck portions 24a, 24b and spheroid bodies
26a, 26b, as well as a cap 76 to be coupled to both halves 16a and
16b so as to fully enclose the interior of the distal tip 16. As
further illustrated, an electrical line 34 may be provided for
coupling the conductive wires 28 to the controller 18 (or
controller 200) and ablation generator 20 and a fluid line 38 may
be provided for providing a fluid connection between the irrigation
pump or drip 22 to the distal tip 16 so as to provide a conductive
fluid (e.g., saline) to the tip 16.
[0111] The device 14a is configured to provide RF ablation via a
virtual electrode arrangement, which includes distribution of a
fluid along an exterior surface of the distal tip 16 and, upon
activation of the electrode array, the fluid may carry, or
otherwise promote, energy emitted from the electrode array to the
surrounding tissue. For example, the nonconductive spheroid body 26
includes an interior chamber (when the first and second halves 26a,
26b are coupled to one another) for retaining at least a spacing
member 300 (also referred to herein as "spacer ball") and one or
more hydrophilic inserts 302a, 302b surrounding the spacing member
300. The interior chamber of the distal tip 16 is configured to
receive and retain a fluid (e.g., saline) therein from a fluid
source. The hydrophilic inserts 302a, 302b are configured receive
and evenly distribute the fluid through the distal tip 16 by
wicking the saline against gravity. The hydrophilic inserts 302a
and 302b can be formed from a hydrophilic foam material (e.g.,
hydrophilic polyurethane).
[0112] As previously described, the distal tip 16 may generally
include a plurality of ports or apertures configured to allow the
fluid to pass therethrough, or weep, from the interior chamber to
an external surface of the distal tip 16. Accordingly, in some
embodiments, all of the ports (e.g., proximal ports 44, medial
ports 45, and distal ports 46) may be configured to allow for
passage of fluid from the inserts 302a, 302b to the exterior
surface of the distal tip 16. However, in some embodiments, only
the medial ports 45 may allow for fluid passage, while the proximal
and distal ports 44, 46 may be blocked via a heat shrink or other
occlusive material.
[0113] The spacer member 300 may formed from a nonconductive
material and may be shaped and sized so as to maintain the
hydrophilic inserts 302a, 302b in sufficient contact with the
interior surface of the distal tip wall, and specifically in
contact with the one or more ports, such that the hydrophilic
inserts 302a, 302b provides uniformity of saline distribution to
the ports. In some embodiments, the spacer member 300 may have a
generally spherical body, corresponding to the interior contour of
the chamber of the spheroid body 26.
[0114] Accordingly, upon positioning the distal tip 16 within a
target site (e.g., tissue cavity to be ablated), the electrode
array can be activated and fluid delivery can be initiated. The
fluid weeping through the ports to the exterior surface of the
distal tip is able to carry energy from electrode array, thereby
creating a virtual electrode. Accordingly, upon the fluid weeping
through the port, a pool or thin film of fluid is formed on the
exterior surface of the distal portion and is configured to ablate
surrounding tissue via the RF energy carried from the electrode
array.
[0115] As previously described herein, conductive wires 28 may
generally extend through a first port (e.g., the distal port 44),
run along an external surface of the spheroid body 26 before
re-entering the lumen of the distal tip 16 through another port
(e.g., the proximal port 46). FIGS. 19, 20, 21A-21B, and 22A-22B
illustrate another arrangement of conductive wires 28, in which at
least four different conductive wires are provided, two of which
serve as supply electrodes and the other two serve as return
electrodes. Each of the four different conductive wires generally
pass through at least two different proximal ports and two
different distal ports, while remaining isolated from one another.
FIG. 19 is a plan view of the ablation device 14a illustrating the
two halves of the device tip 16a, 16b separated from one another
and showing the external surface each, while FIG. 20 shows the
interior surface of each.
[0116] FIGS. 21A and 21B are enlarged views of the spheroid body of
the first halve 16a of the device 14a showing the exterior and
interior surfaces, respectively, and further illustrating the
particular arrangement of first and second conductive wires 28(1)
and 28(2), partly in phantom, extending through proximal and distal
ports 44, 46 of the spheroid body 26a. The following description of
the first and second conductive wires 28(1) and 28(2) provides a
general pathway of each wire, including passages through ports and
extensions along lengths of the interior and exterior surfaces of
the tip 16. In the illustrated embodiment, a first conductive wire
28(1) may serve as a return electrode while a second conductive
wire 28(2) may serve as a supply electrode.
[0117] As shown, the first conductive wire 28(1) extends within the
lumen of the tip 16a and passes through proximal port 44(1),
extends along the exterior surface of the spheroid body 26a towards
the distal ports (generally parallel to longitudinal axis of
device), passes through distal port 46(1), extends along the
interior surface of the body 26a towards adjacent distal ports
(generally transverse to longitudinal axis of the device), passes
through distal port 46(2), extends along the exterior surface of
the spheroid body 26a back towards the proximal ports, passes
through proximal port 44(2), extends along the interior surface of
body 26a towards adjacent proximal ports, passes through proximal
port 44(5), extends along the exterior surface of the spheroid body
26a back towards the distal ports, passes through distal port
46(5), extends along the interior surface of the body 26a towards
adjacent distal ports, passes through distal port 46(6), extends
along the exterior surface of the spheroid body 26a back towards
the proximal ports, passes through proximal port 44(6), and extends
back through lumen of the tip 16a. Accordingly, the first
conductive wire 28(1) has at least four portions that extend along
the exterior surface of the spheroid body 26a.
[0118] The second conductive wire 28(2) extends within the lumen of
the tip 16a and passes through distal port 44(3), extends along the
exterior surface of the spheroid body 26a towards the distal ports
(generally parallel to longitudinal axis of device), passes through
distal port 46(3), extends along the interior surface of the body
26a towards adjacent distal ports (generally transverse to
longitudinal axis of the device), passes through distal port 46(4),
extends along the exterior surface of the spheroid body 26a back
towards the proximal ports, passes through proximal port 44(4), and
extends back through lumen of the tip 16a. Accordingly, the second
conductive wire 28(2) has at least two portions that extend along
the exterior surface of the spheroid body 26a.
[0119] FIGS. 22A and 22B are enlarged views of the spheroid body of
the second halve 16b of the device 14a showing the exterior and
interior surfaces, respectively, and further illustrating the
particular arrangement of third and fourth conductive wires 28(3)
and 28(4) extending through proximal and distal ports of the
spheroid body 26b. The following description of the third and
fourth conductive wires 28(3) and 28(4) provides a general pathway
of each wire, including passages through ports and extensions along
lengths of the interior and exterior surfaces of the tip 16. In the
illustrated embodiment, a third conductive wire 28(3) may serve as
a return electrode while a second conductive wire 28(4) may serve
as a supply electrode.
[0120] As shown, the third conductive wire 28(3) extends within the
lumen of the tip 16a and passes through proximal port 44(9),
extends along the exterior surface of the spheroid body 26b towards
the distal ports (generally parallel to longitudinal axis of
device), passes through distal port 46(9), extends along the
interior surface of the body 26b towards adjacent distal ports
(generally transverse to longitudinal axis of the device), passes
through distal port 46(10), extends along the exterior surface of
the spheroid body 26b back towards the proximal ports, passes
through proximal port 44(10), and extends back through lumen of the
tip 16a. Accordingly, the third conductive wire 28(3) has at least
two portions that extend along the exterior surface of the spheroid
body 26b.
[0121] The fourth conductive wire 28(4) extends within the lumen of
the tip 16b and passes through proximal port 44(7), extends along
the exterior surface of the spheroid body 26b towards the distal
ports (generally parallel to longitudinal axis of device), passes
through distal port 46(7), extends along the interior surface of
the body 26b towards adjacent distal ports (generally transverse to
longitudinal axis of the device), passes through distal port 46(8),
extends along the exterior surface of the spheroid body 26b back
towards the proximal ports, passes through proximal port 44(8),
extends along the interior surface of body 26b towards adjacent
proximal ports, passes through proximal port 44(11), extends along
the exterior surface of the spheroid body 26b back towards the
distal ports, passes through distal port 46(11), extends along the
interior surface of the body 26b towards adjacent distal ports,
passes through distal port 46(12), extends along the exterior
surface of the spheroid body 26b back towards the proximal ports,
passes through proximal port 44(12), and extends back through lumen
of the tip 16a. Accordingly, the fourth conductive wire 28(4) has
at least four portions that extend along the exterior surface of
the spheroid body 26b.
[0122] Furthermore, each of the four conductive wires 28(1)-28(4)
remain electrically isolated and independent from one another such
that, each, or one or more sets of a combination of, the conductive
wires, can independently receive an electrical current from the
ablation generator and independently conduct energy, the energy
including RF energy. This allows energy to be selectively delivered
to a designated conductive wire or combination of conductive wires.
This design also enables the ablation device to function in a
bipolar mode because a first conductive wire (or combination of
conductive wires) can deliver energy to the surrounding tissue
through its electrical connection with an ablation generator while
a second conductive wire (or combination of conductive wires) can
function as a ground or neutral conductive member.
[0123] The independent control of each wire or sets of wires allows
for activation (e.g., emission of RF energy) of corresponding
portions of the electrode array. For example, the electrode array
may be partitioned into specific portions which may correspond to
clinical axes or sides of the distal portion of the device. In one
embodiment, the electrode array may include at least four distinct
portions (i.e., individual or sets of conductive wires)
corresponding to four clinical axes or sides of the distal portion
(e.g, four sides or quadrants around spheroid body).
[0124] FIG. 23 is a schematic illustration of the ablation device
14a illustrating delivery of fluid from the irrigation pump 22, as
controlled by the controller 19, to the hydrophilic inserts 302a,
302b within the interior chamber of the distal tip 16, wherein the
fluid can be subsequently distributed to an exterior surface of the
spheroid body 26 resulting in a virtual electrode arrangement upon
activation of one or more portions of the electrode array. As
shown, the saline may be distributed through at least the medial
ports 45, such that the weeping saline is able to carry electrical
current from electrode array, such that energy is transmitted from
the electrode array to the tissue by way of the saline weeping from
the ports, thereby creating a virtual electrode. Accordingly, upon
the fluid weeping through the medial port, a pool or thin film of
fluid is formed on the exterior surface of the spheroid body 26 and
is configured to ablate surrounding tissue via the electrical
current carried from the electrode array.
[0125] FIGS. 24 and 25 are perspective and plan views of a
detachable mount 400 for holding and maintaining a temperature
probe 402 (or any other separate monitoring device) at a desired
position, as indicated by arrow 406, relative to the spheroid body
26 of the distal tip of the ablation device 14. In particular, the
mount 400 allows for an operator (e.g., surgeon) to releasably
couple a temperature probe 402, or other measurement device, to the
ablation device 14a and further position the working end 404 of the
probe 402 in close proximity to the spheroid body 2 for the
collection of temperature data during an RF ablation procedure.
[0126] As previously described herein, the controller 18 (as well
as 19 or 200) may be configured to provide a surgeon with the
ability to control ablation, such as controlling the supply of
power to one or more conductive wires as well as control the
delivery of fluid to the device tip 16. Furthermore, the controller
18 may provide device status (e.g., power on/off, ablation on/off,
fluid delivery on/off) as well as one or more parameters associated
with the RF ablation (e.g., energy output, elapsed time, timer,
temperature, conductivity, etc.). Thus, in some instances,
particularly when using the CAS system 100 described previously
herein, it may be important to monitor at least the temperature
adjacent to the device tip 16 during the ablation procedure, as
well as pre-ablation and post-ablation, as temperature may be
indicative of the status of surrounding tissue that is being, or is
intended to be, ablated. Furthermore, it may be important to
monitor the temperature at certain distances from the device tip 14
and at certain angles. Current devices may include a thermocouple
mechanism integrated into the device. However, such configurations
lack the ability to obtain temperature measurement at specific
distances and angles relative to the ablation tip. The mount 400 is
configured to provide a surgeon with the ability to adjacent the
angle at which the temperature probe is positioned relative to the
device tip 16 as well as the distance from the device tip 16,
thereby overcoming the drawbacks of integrated thermocouples.
[0127] As shown, the mount 400 generally includes a body having a
first end 408 configured to be releasably coupled to at least the
proximal end of the device 14 by way of a clamping mechanism or
latch-type engagement. The first end 408 includes a top guard
member 410 configured to partially enclose at least the proximal
end of the device 14, to further enhance securement of the mount
400 to the device 14. The mount 400 further includes an arm member
412 extending from the first end 408 and providing a second end 414
positioned a distance from the first end 408. The second end 414 is
configured to hold the temperature probe 402 at a desired position,
including a desired distance from the spheroid body 26 and a
desired angle .theta. relative to the longitudinal axis of the
ablation device. For example, in one embodiment, the second end 414
may include a bore or channel configured to receive and retain a
portion of the temperature probe 402 within. The second end 414 may
further allow for the temperature probe 402 to translate along the
bore or channel, as indicated by arrow 416, to thereby adjust the
distance of the temperature probe tip 404 relative to the spheroid
body of the device tip. In some embodiments, the arm 412 and/or
second end 414 may articulate relative to one another and/or the
first end 408. Accordingly, the angle of the temperature probe 402
may also be adjusted as desired.
[0128] Accordingly, the system of the present invention is
configured to provide a user with multiple features allowing custom
ablation shaping, which includes the creation of custom,
user-defined ablation geometries depending on the target site. In
particular, rather than simply providing a universal RF ablation
shape or profile, the system allows for a user to customize the
emission of energy to a targeted portion of marginal tissue within
the cavity, which is particularly useful in instances in which
non-uniform ablation is desired. The customized emission of energy
may include a specific shape or geometry of emission, as well as
time and depth of penetration of RF energy.
[0129] The devices, systems, and methods of the present disclosure
can help to ensure that all microscopic disease in the local
environment has been treated. This is especially true in the
treatment of tumors that have a tendency to recur. Furthermore, by
providing custom ablating shaping, in which the single ablation
device may provide numerous RF energy emission shapes or profiles,
the system of the present invention allows for non-uniform ablation
to occur. This is particularly useful in controlling ablation shape
so as to avoid vital organs and any critical internal/external
structures (e.g., bone, muscle, skin) in close proximity to the
tumor site, while ensuring that residual marginal tissue within the
local environment has been treated.
[0130] As used in any embodiment herein, the term "controller",
"module", "subsystem", or the like, may refer to software, firmware
and/or circuitry configured to perform any of the aforementioned
operations. Software may be embodied as a software package, code,
instructions, instruction sets and/or data recorded on
non-transitory computer readable storage medium. Firmware may be
embodied as code, instructions or instruction sets and/or data that
are hard-coded (e.g., nonvolatile) in memory devices. "Circuitry",
as used in any embodiment herein, may comprise, for example, singly
or in any combination, hardwired circuitry, programmable circuitry
such as computer processors comprising one or more individual
instruction processing cores, state machine circuitry, and/or
firmware that stores instructions executed by programmable
circuitry. The controller or subsystem may, collectively or
individually, be embodied as circuitry that forms part of a larger
system, for example, an integrated circuit (IC), system on-chip
(SoC), desktop computers, laptop computers, tablet computers,
servers, smart phones, etc.
[0131] Any of the operations described herein may be implemented in
a system that includes one or more storage mediums having stored
thereon, individually or in combination, instructions that when
executed by one or more processors perform the methods. Here, the
processor may include, for example, a server CPU, a mobile device
CPU, and/or other programmable circuitry.
[0132] Also, it is intended that operations described herein may be
distributed across a plurality of physical devices, such as
processing structures at more than one different physical location.
The storage medium may include any type of tangible medium, for
example, any type of disk including hard disks, floppy disks,
optical disks, compact disk read-only memories (CD-ROMs), compact
disk rewritables (CD-RWs), and magneto-optical disks, semiconductor
devices such as read-only memories (ROMs), random access memories
(RAMs) such as dynamic and static RAMs, erasable programmable
read-only memories (EPROMs), electrically erasable programmable
read-only memories (EEPROMs), flash memories, Solid State Disks
(SSDs), magnetic or optical cards, or any type of media suitable
for storing electronic instructions. Other embodiments may be
implemented as software modules executed by a programmable control
device. The storage medium may be non-transitory.
[0133] As described herein, various embodiments may be implemented
using hardware elements, software elements, or any combination
thereof. Examples of hardware elements may include processors,
microprocessors, circuits, circuit elements (e.g., transistors,
resistors, capacitors, inductors, and so forth), integrated
circuits, application specific integrated circuits (ASIC),
programmable logic devices (PLD), digital signal processors (DSP),
field programmable gate array (FPGA), logic gates, registers,
semiconductor device, chips, microchips, chip sets, and so
forth.
[0134] Reference throughout this specification to "one embodiment"
or "an embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment. Thus, appearances of the
phrases "in one embodiment" or "in an embodiment" in various places
throughout this specification are not necessarily all referring to
the same embodiment. Furthermore, the particular features,
structures, or characteristics may be combined in any suitable
manner in one or more embodiments.
[0135] The terms and expressions which have been employed herein
are used as terms of description and not of limitation, and there
is no intention, in the use of such terms and expressions, of
excluding any equivalents of the features shown and described (or
portions thereof), and it is recognized that various modifications
are possible within the scope of the claims. Accordingly, the
claims are intended to cover all such equivalents.
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