U.S. patent application number 15/863122 was filed with the patent office on 2018-05-10 for anchored rf ablation device for the destruction of tissue masses.
This patent application is currently assigned to Acessa Health Inc.. The applicant listed for this patent is Acessa Health Inc.. Invention is credited to Jeffrey M. COHEN, Gordon E. EPSTEIN, Adam HAGMANN, Bruce B. LEE, Richard SPERO.
Application Number | 20180125566 15/863122 |
Document ID | / |
Family ID | 37605129 |
Filed Date | 2018-05-10 |
United States Patent
Application |
20180125566 |
Kind Code |
A1 |
EPSTEIN; Gordon E. ; et
al. |
May 10, 2018 |
ANCHORED RF ABLATION DEVICE FOR THE DESTRUCTION OF TISSUE
MASSES
Abstract
The inventive ablation element comprises an elongated cannula
having a proximal end and a distal end. The cannula defines an
internal lumen and a cannula axis. A plurality of conductors
contained within the lumen, each having a proximal end proximate
the proximal end of the cannula, and a distal end proximate the
distal end of the cannula. A plurality of ablation stylets each has
a proximal end and a distal end, and each coupled to the distal end
of a respective conductor, the conductors together with their
respective stylets being mounted for axial movement. A trocar point
defined proximate the distal end of the cannula. A deflection
surface positioned between the trocar point and the proximal end of
the cannula, the deflection surface being configured and positioned
to deflect at least some of the stylets laterally with respect to
the cannula axis in different directions defining an ablation
volume.
Inventors: |
EPSTEIN; Gordon E.; (Austin,
TX) ; LEE; Bruce B.; (Austin, TX) ; COHEN;
Jeffrey M.; (Austin, TX) ; HAGMANN; Adam;
(Austin, TX) ; SPERO; Richard; (Austin,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Acessa Health Inc. |
Austin |
TX |
US |
|
|
Assignee: |
Acessa Health Inc.
Austin
TX
|
Family ID: |
37605129 |
Appl. No.: |
15/863122 |
Filed: |
January 5, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13969600 |
Aug 18, 2013 |
9861426 |
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15863122 |
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11429921 |
May 8, 2006 |
8512333 |
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13969600 |
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11173928 |
Jul 1, 2005 |
8080009 |
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11429921 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2018/1869 20130101;
A61B 2018/1425 20130101; A61B 18/14 20130101; A61B 2018/00577
20130101; A61B 18/1815 20130101; A61B 2018/143 20130101; A61B
18/1477 20130101; A61B 2018/1405 20130101; A61B 2018/00702
20130101; A61B 2018/00273 20130101; A61B 2018/1432 20130101; A61B
18/18 20130101; A61B 2018/00791 20130101; A61B 2018/00738 20130101;
A61B 2017/3454 20130101; A61B 2018/00559 20130101; A61B 2018/1475
20130101; A61B 2018/0094 20130101; A61B 17/3421 20130101; A61B
2018/00214 20130101; A61B 2018/00761 20130101; A61B 2018/1467
20130101 |
International
Class: |
A61B 18/14 20060101
A61B018/14; A61B 18/18 20060101 A61B018/18; A61B 17/34 20060101
A61B017/34 |
Claims
1. An ablation apparatus, comprising: an elongated cannula having a
proximal end and a distal end, the cannula defining an internal
lumen and a cannula axis; a plurality of ablation stylets each
having a proximal end and a distal end, the stylets comprising a
deflectable material and having a low profile configuration when
straightened within the cannula; and one or more deflection
surfaces positioned along the cannula and configured to deflect at
least some of the stylets into a deployed configuration where the
stylets are translated longitudinally in a distal direction to
extend at an angle relative to the cannula axis such that the
stylets are straightened externally of the cannula, wherein the
deployed configuration defines an ablation volume.
2. The apparatus of claim 1 wherein the plurality of stylets
comprise at least one central ablation stylet which is positioned
to extend along the cannula axis in the deployed configuration.
3. The apparatus of claim 2 further comprising a central conductor
contained within the internal lumen, the central conductor
extending through the cannula proximal to the distal end of the
cannula.
4. The apparatus of claim 3 wherein central conductor is coupled
with the at least one central ablation stylet.
5. The apparatus of claim 1 further comprising a plurality of
conductors contained within the internal lumen, wherein each of the
conductors is coupled to the respective proximal end of a
corresponding stylet and are longitudinally translatable with the
corresponding stylet.
6. The apparatus of claim 5 wherein the plurality of conductors is
selected from the group consisting of electrical conductors, radio
frequency conductors, microwave conductors, and optical
conductors.
7. The apparatus of claim 5 wherein each of the conductors is
integral with its respective ablation stylet.
8. The apparatus of claim 1 further comprising a trocar point
defined proximate the distal end of the cannula.
9. The apparatus of claim 1 wherein each of the ablation stylets is
configured to assume a straightened configuration in the absence of
an external force.
10. The apparatus of claim 1 further comprising an actuator
configured to longitudinally translate the plurality of ablation
stylets.
11. The apparatus of claim 1 wherein the one or more deflection
surfaces comprise a ramp positioned along the cannula.
12. The apparatus of claim 11 wherein the one or more deflection
surfaces comprises a plurality of channels guiding the ablation
stylets to the one or more ramps.
13. The apparatus of claim 1 further comprising an anchor mounted
for movement between an internal position and an anchoring position
extending laterally from the cannula.
14. The apparatus of claim 13 further comprising a drive member
disposed within the lumen and coupled to the anchor to drive the
anchor between the internal position and the anchoring
position.
15. The apparatus of claim 13 wherein the anchor comprises at least
two pointed members mounted for movement in directions which have
vector components which extend away from the axis or the cannula
and away from each other.
16. The apparatus of claim 13 wherein the at least two pointed
members extend in a direction with vector component that extends in
a direction opposite to the direction in which cannula extends.
17. An ablation apparatus, comprising: an elongated cannula having
a proximal end and a distal end, the cannula defining an internal
lumen and a cannula axis; a plurality of ablation stylets including
at least one central ablation stylet which is positioned to extend
along the cannula axis, the stylets comprising a deflectable
material and having a low profile configuration when straightened
within the cannula; and one or more deflection surfaces positioned
along the cannula and configured to deflect at least some of the
stylets into a deployed configuration where the stylets are
translated longitudinally in a distal direction to extend at an
angle relative to the cannula axis such that the stylets are
straightened externally of the cannula, wherein the deployed
configuration defines an ablation volume.
18. The apparatus of claim 17 further comprising a central
conductor contained within the internal lumen, the central
conductor extending through the cannula proximal to the distal end
of the cannula.
19. The apparatus of claim 18 wherein central conductor is coupled
with the at least one central ablation stylet.
20. The apparatus of claim 17 further comprising a plurality of
conductors contained within the internal lumen, wherein each of the
conductors is coupled to the respective proximal end of a
corresponding stylet and are longitudinally translatable with the
corresponding stylet.
21. The apparatus of claim 17 further comprising a trocar point
defined proximate the distal end of the cannula.
22. The apparatus of claim 17 further comprising an actuator
configured to longitudinally translate the plurality of ablation
stylets.
23. The apparatus of claim 17 wherein the one or more deflection
surfaces comprise a ramp positioned along the cannula.
24. The apparatus of claim 23 wherein the one or more deflection
surfaces comprises a plurality of channels guiding the ablation
stylets to the one or more ramps.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application 13/969,600 filed Aug. 18, 2013 (now U.S. Pat. No.
9,861,426), which is a continuation-in-part of U.S. patent
application 11/429,921 filed May 8, 2006 (now U.S. Pat. No.
8,512,333), which is a continuation-in-part of U.S. patent
application 11/173,928 filed on Jul. 1, 2005 (now U.S. Pat. No.
8,080,009), the disclosures of which are incorporated by
reference.
BACKGROUND
[0002] In the United States, approximately 230,000 women have
hysterectomies annually. The primary reason for performing a
hysterectomy is the presence of uterine fibroids. These fibroids
grow in the wall of the uterus and may range in size up to several
inches across. In the United States alone, there are more than six
million women with uterine fibroid symptoms who prefer to suffer,
rather than endure the risks and inconveniences associated with
major surgery, especially a major surgery that results in
infertility. Outside of the United States, the situation is much
the same, with millions of women suffering with fibroids in need of
a safe alternative to hysterectomy.
[0003] Recently, another treatment option (uterine artery
embolization) has been introduced. Generally, this procedure
involves embolization of the arteries which feed the urine fibroid.
This results in cutting off the blood supply to the fibroid and the
shrinkage of the fibroid over time. However, the unacceptably high
rate of complications severely limits its appeal to patients.
[0004] Myomectomy, each generally involves the surgical removal of
the fibroid through the use of classical surgical procedures, is
another treatment option. However, due to its high rate of
complications and long recovery time, this option is also not very
appealing to patients. Typical complications involve risk of
infection, relatively severe postsurgical pain, damage to the
uterus and other risks normally associated with such types of
surgery. Moreover, such damage may be relatively subtle and may
only come to light when the uterus begins to swell in pregnancy and
ruptures at a weak point created during the surgery, resulting in
loss of the fetus.
[0005] Still another alternative to treat the discomfort associated
with uterine fibroids is the removal of the endometrium which lines
the uterus. However, this procedure results in infertility.
[0006] In an attempt to address these issues, an RF ablation probe
of the type used to treat tumors in the human liver by hyperthermia
has been successfully demonstrated to substantially shrink or
eliminate uterine fibroids.
[0007] See, for example, U.S. Pat. No. 6,840,935 issued to Lee on
Jan. 11, 2005, the disclosure of which is incorporated herein by
reference. In that patent a method for treating pelvic tumors, such
as uterine leiomyomata, includes inserting an ablation apparatus
into a pelvic region and positioning the ablation apparatus either
proximate to or into a pelvic tumor. The method further includes
using a laparoscope and an imaging device, such as an ultrasound
machine, to confirm the location of the pelvic tumor and placement
of the ablation apparatus. An ablation apparatus with multiple
needles or deployable arms that are inserted into the pelvic tumor
is disclosed. The method involves delivering electromagnetic energy
or other energy through the ablation apparatus to the pelvic tumor
to induce hyperthermia and ablate the tumor.
[0008] The particular device disclosed for ablating the tumor in
U.S. Pat. No. 6,840,935 is of the type disclosed in U.S. Pat. No.
5,728,143, issued to Gough et al. on Mar. 17, 1998. Generally, that
device comprises a plurality of resilient springy RF ablation
antennae, or stylets, which are preformed with a curved
configuration which they assume after exiting a sharp trocar-tipped
catheter. The tip of the catheter is deployed in uterine fibroid
tissue to be destroyed. The stylets are then deployed into the
tissue to be destroyed. Generally, as the antennae exit the trocar
tip, they pierce the tissue of the uterine fibroid along curved
paths which are defined by the preformed springy shape of the
stylet. The deployed stylets with their respective preformed shapes
and the positions within which they are deployed thus define the
ablation volume. Various shape volumes may be defined by varying
the configuration of the curves which are preformed into the
different springy stylets convey given trocar-pointed catheter.
Such devices are manufactured by Rita Medical Systems of Mountain
View, Calif. The hallmark of such devices is that the stylets
assume their pre-formed configuration as they emerge from the
trocar tip.
SUMMARY OF THE INVENTION
[0009] In accordance with the invention, it has been observed that
difficulties are encountered in using conventional curved stylet
ablation systems. More particularly, it has been discovered that
uterine fibroid tissues tend to be difficult to pierce because,
unlike other types of tumors, uterine fibroids are comprised of
relatively hard muscle-like tissues and the curved stylets tend to
deform during deployment. They are thus not very effective in
piercing a uterine stylet. To a limited extent, the difficulty of
piercing the fibroid with the curved stylets may be mitigated by
advancing very small increments of the ablation stylet into the
fibroid, applying radiation to the stylet to induce hyperthermia
and degrade the physical integrity of the tissue surrounding the
stylets. The stylets may then be advanced into the somewhat
deteriorated and softened tissue and the application of radiation
to the stylets continued to enlarge the physically deteriorated
regions of the fibroid. After a time, the process of advancing the
stylet to a point where resistance is encountered, and applying
energy to the stylet to cause ablation of the urine fibroid tissue
is repeated until penetration into the desired destruction of
tissue has been achieved, or the stylets have been fully
deployed.
[0010] At that point, ablation energy is applied to the stylets
until the desired degree of tissue ablation has been achieved. If
necessary, the trocar point may then be advanced for a repetition
of the ablation operation or it may be removed and redeployed in
another volume of tissue to be destroyed by the deployment of the
stylets.
[0011] While the iterative advancement of the stylets, punctuated
by relatively long periods of time during which advancement cannot
be implemented and the surgeon must wait for the desired degree of
deterioration of the tissue into which the antennae will next be
advanced, will work to effectively and minimally-invasively ablate
a uterine fibroid, the procedure is extremely time-consuming
compared to a procedure in which antennae may be fully deployed and
radiation applied to a large volume of a uterine fibroid during a
single application of RF energy.
[0012] Accordingly, while the above procedure has seen some
implementation, the time necessary for the procedure has made it
relatively expensive and thus it is not available to many
individuals. Moreover, the skill required for the performance of
the procedure is relatively high, and thus few doctors are able to
perform the procedure. Proliferation of this approach is not likely
in view of the steep learning curve and the small number of
individuals competent to perform this procedure. This has been the
case, despite the effectiveness of ablation in destroying uterine
fibroid tissue and the attendant absorption of necrotic tissue by
the body, resulting in substantial elimination of the fibroid.
[0013] Nevertheless, in accordance with the invention, it is
believed that a quick and particularly easy to implement RF
ablation procedure is provided, which carries a relatively low risk
of complications and a lower likelihood, under a typically
encountered set of circumstances, that the uterus will be damaged
and fail during a subsequent pregnancy.
[0014] In accordance with the invention an ablation element
comprises an elongated cannula having a proximal end and a distal
end. The cannula defines an internal lumen within the cannula and a
cannula axis. A trocar point is positioned proximate the distal end
of the cannula. A conductor is contained within the cannula. But
conductor has a proximal end and a distal end. The distal end of
the conductor is proximate the distal end of the cannula. A
plurality of ablation stylets each has a proximal end and a distal
end, and each coupled at the respective proximal end of the stylet
to the distal end of the conductor, the stylets comprise a
deflectable material and defined a substantially straight shape.
The conductor together with the stylets are mounted for axial
movement within the cannula. A deflection surface is positioned
between the tip of the trocar point and the proximal end of the
cannula. The deflection surface is configured and positioned to
deflect, in response to axial movement of the stylets in a
direction from the proximate end of the cannula to the distal end
of the cannula, at least one of the stylets laterally with respect
to the cannula axis in different directions along paths which are
substantially straight for that portion of the stylet which has a
suited the trocar point. These paths define an ablation volume.
[0015] The conductor may be selected from the group consisting of
electrical conductors, radio frequency conductors, microwave
conductors and optical conductors or light pipes.
[0016] Each of the stylets may be configured to assume a
substantially straight configuration in the absence of external
forces.
[0017] An ablation element further comprises a motor member or
members coupled to the conductors to drive axial movement of the
stylets in directions from the proximal end of the cannula to the
distal end of the cannula, and from the distal end of the cannula
to the proximal end of the cannula through a plurality of
positions. The trocar point may be defined at the distal end of a
trocar member, the trocar member having an outside surface, the
cannula having an outside surface, the trocar member having a
proximal end secured proximate to the distal end of the elongated
cannula, and the outside surface of the cannula and the outside
surface of the trocar point defining a trocar surface. The trocar
member acts as a stylet mandrel to deflect the stylets, which may
be electrodes, along paths which are substantially straight after
the stylets exit the mandrel into the tissue to be ablated.
[0018] The deflection surface comprises a number of ramps defined
proximate the proximal end of the trocar point, the distal ends of
the stylets being positionable proximate to the ramps and within
the trocar surface.
[0019] The conductor and the stylets are electrical conductors, and
each of the stylets may be configured to assume a substantially
straight configuration in the absence of external forces.
[0020] The deflection surface comprises a plurality of channels
guiding the distal ends of the stylets to the ramps. The cannula
may be secured to the trocar member with the outside surface of the
cannula proximate to the outside surface of the trocar member.
[0021] The ablation element also comprises an anchor mounted for
movement between an internal position disposed within the trocar
surface and an anchoring position extending laterally from the
trocar surface through points external of the lumen; and a drive
member disposed within the lumen and coupled to the anchor to drive
the anchor between the internal position and the anchoring
position.
[0022] The anchor comprises at least two pointed members mounted
for movement in directions which have vector components which
extend away from the axis of the cannula and away from each other.
The pointed members also preferably extend in a direction with a
vector component that extends in a direction opposite to the
direction in which the trocar point extends.
[0023] The conductors are driven by a drive mechanism which allows
the conductors to move independently. The conductors have a length,
a width and a thickness, the width being greater than the
thickness, and terminate in a point oriented to allow deflection by
the deflection surface. The conductors extend in different
directions when they exit the deflection surface and extend to a
variable extent.
[0024] The conductors are driven by a drive circuit which varies
the amount of energy supplied to the stylets and/or the length of
the stylets and/or the length of the time during which power is
supplied to the stylets and/or the angular orientation of the
ablation element (through the variation of ramp deflection
angle.
[0025] The parameters of stylet length, stylet power, stylet
actuation time and/or angular orientation may be controlled by a
computer in response to a computer program having an input
comprising feedback information from the tissue area being operated
on and/or a preset program.
[0026] The anchor is mounted for movement between an internal
position disposed within the trocar surface and an anchoring
position extending laterally from the trocar surface through points
external of the lumen. The drive member may be disposed within the
lumen and coupled to the anchor to drive the anchor between the
internal position and the anchoring position. The desired motive
force for advancing the stylets and/or optional anchors may be
provided by a finger operated slidably mounted gripping surface
which the surgeon uses to manually advance the conductor and the
stylets attached to the end of the conductor. The gripping surface
may be slidably mounted on a handle within which the proximal end
of the trocar is mounted. The anchor comprises at least two pointed
members mounted for movement in directions which have vector
components which extend away from the axis or the cannula and away
from each other.
[0027] As alluded to above, the front end of the inventive catheter
is a trocar point defined at the distal end of a trocar member. The
trocar member has an outside surface. The cannula has an outside
surface, and the trocar member has a proximal end secured proximate
to the distal end of the elongated cannula. The outside surface of
the cannula and the outside surface of the trocar point define the
trocar surface. The trocar member bears a plurality of deflection
surfaces. The deflection surface comprises a number of ramps
defined within the trocar member. The distal ends of the stylets
are positionable proximate to the deflection surfaces and within
the trocar surface.
[0028] In accordance with a particularly preferred embodiment of
the invention, it is contemplated that a graphical user interface
and a pair of electrical switches, for example a joystick and a
pushbutton, will be used to switch between operating parameter
options for the inventive catheter which are displayed on a
graphical user interface (or other information conveying device
such as an audio cue generator). The surgeon navigates a menu, for
example, using a joystick looking at or hearing an electronically
generated audio signal, such as a voice, presenting various options
and selects the desired option by pushing the electrical switch. In
principle, this can be done on a single switch incorporating
joystick and pushbutton features.
[0029] Optionally, the electrical switches which operate the system
may be recessed partially or fully in order to minimize the
likelihood of unintentional actuation. Additional protection may be
provided by requiring two motions within a relatively short period
of time in order to achieve a change in the control of the
system.
[0030] In accordance with a particularly preferred version of the
invention, this is achieved by having a human voice present options
and acknowledge instructions, which may be given to the system
orally using voice recognition technology. This allows the surgeon
to operate without having to look away from visual displays guiding
the operation, the patient, instruments and so forth, thus removing
potential losses of information. A display siumultaeneously
displays all relevant information to provide a quicker provision of
information to the surgeon.
[0031] In accordance with the invention it is contemplated that
laser manufacturing techniques may be used to manufacture the
anchors and perhaps the anchor deflection surfaces.
[0032] Preferably, the point of the trocar is milled to a point
with three surfaces. Stylets are milled in the manner of a
hypodermic needle. Stylets are oriented to cooperate with the
deflection surfaces which deflect them. A cooperating low friction
insulator ring, for example, made of Teflon, cooperates with the
deflection surfaces to deflect hypotube electrode stylets.
[0033] The present invention contemplates the use of rearwardly
deployed anchoring stylets which act as retractable barbs for
maintaining the position of the trocar point during forward
deployment of the radiofrequency (RF) electrode ablation
stylets.
[0034] In accordance with the present invention, a stylet operating
member, optionally a stylet push member, which may be a tube, is
positioned on one side of a tubular compression/tension operator,
for example on the inside of the compression/tension operator.
Similarly, in accordance with the present invention, and anchor
member operating member, optionally an anchor pull member, which
may be a tube, is positioned on the other side of a tubular
compression/tension operator, for example on the outside of the
compression/tension operator. Such outside placement is
particularly advantageous in the case where the anchoring member is
of relatively wide dimension and large size.
[0035] In accordance with a preferred embodiment of the invention,
the compression tension operator is secured at the proximal end to
the handle of the ablation instrument and at the distal end to the
anchoring member deflection surface and the hypotube electrode
stylet deflection surface.
[0036] The invention contemplates a plurality of hypotube electrode
stylets which are bound together as a unitary structure and
advanced by a single push tube or wire.
[0037] It is also contemplated that the inventive instrument will
include channels for flushing clean. In accordance with the
inventive system, the frequency with which flushing should be
performed is minimized through the use of a trocar front face which
is substantially closed (except for a single undeflected hypotube
which exits the front face of the trocar) and providing for exit of
hypotubes through the cylindrical side wall of the trocar
point.
[0038] In accordance with a particularly preferred embodiment of
the invention, the anchor member is separate from the anchor push
tube, and is connected it to by mating or other interlocking
structure.
[0039] Deflection surfaces for both the hypotube stylets and
anchors are selected to result in strains in the range of 2% to 8%,
preferably about 4%, for example 3.5% to 4.5%, which represents a
reasonable compromise between instrument longevity and a relatively
large amount of deflection.
[0040] An insulation sleeve is positioned between the anchors and
the hypotube stylets in order to allow separate electrical
actuation and ablation with either or both of the anchors and the
hypotube stylets.
[0041] The hypotube stylets contain thermocouples which are used to
measure the temperature of ablated tissue, thus ensuring that the
tissue will be raised to the correct temperature for a sufficient
period of time to ablate tissue resulting in the creation of
necrotic tissue which may be absorbed by the body.
[0042] In accordance with the preferred embodiment of the
invention, hypotube stylets are deployed forwardly or distally
while anchors are deployed in a proximal direction or rearwardly.
Alternatively, the hypotube stylets may be deployed in a proximal
direction or rearwardly, while anchors are deployed forwardly or
distally.
[0043] As compared to a conventional hysterectomy, the present
invention is directed to a device for the treatment of uterine
fibroids and other tissue masses that meets the needs of women by
conserving the uterus and reducing recovery time from 6-8 weeks to
3-10 days.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 is a plan view of the multiple antenna ablation
device of the invention with the cover removed and partially in
cross-section to illustrate its operation;
[0045] FIG. 2 is a front view of the inventive probe with anchor
system of the device along lines 2-2 of FIG. 1, but illustrating
the instrument after deployment of the anchor and antennae
(stylets);
[0046] FIG. 3 is a cross-sectional view of the tip of the catheter
constructed in accordance with the present invention;
[0047] FIG. 4 is a plan view of the apparatus of the present
invention with anchors and ablation hypotubes not deployed;
[0048] FIG. 5 is a plan view of the catheter with seven hypotube
ablation electrodes and four anchors deployed;
[0049] FIG. 6 is a perspective view of the catheter structure of
FIG. 5;
[0050] FIG. 7 is a cross-sectional view illustrating deployed
hypotubes and anchors;
[0051] FIG. 8 is a plan view illustrating a trocar point with
deflection surfaces for guiding hypotubes;
[0052] FIG. 9 is a perspective view illustrating a trocar point
with deflection surfaces for guiding hypotubes;
[0053] FIG. 10 is a top plan view illustrating a trocar point with
deflection surfaces for guiding hypotubes;
[0054] FIG. 11 is a bottom plan view illustrating a trocar point
with deflection surfaces for guiding hypotubes;
[0055] FIG. 12 is a rear view illustrating a trocar point with
deflection surfaces for guiding hypotubes;
[0056] FIG. 13 is a perspective view illustrating a core for
holding a plurality of hypotubes;
[0057] FIG. 14 is a side plan view illustrating a core for holding
a plurality of hypotubes;
[0058] FIG. 15 is a rear view illustrating a core for holding a
plurality of hypotubes;
[0059] FIG. 16 is a side plan view illustrating a core holding a
plurality of hypotubes;
[0060] FIG. 17 is a perspective view illustrating a core holding a
plurality of hypotubes;
[0061] FIG. 18 is a rear view illustrating a core holding a
plurality of hypotubes;
[0062] FIG. 19 is a perspective detailed view illustrating a core
holding a plurality of hypotubes;
[0063] FIG. 20 is a perspective detailed view illustrating the tips
of a plurality of hypotubes when they are being held in a core as
illustrated in FIG. 19;
[0064] FIG. 21 is a side plan view illustrating a rearward
anchoring member;
[0065] FIG. 22 is a perspective view illustrating a rearward
anchoring member;
[0066] FIG. 23 is an end view illustrating a rearward anchoring
member;
[0067] FIG. 24 is a plan view illustrating a rearward anchoring
member;
[0068] FIG. 25 is an end view illustrating an anchor deflecting
mandrel member;
[0069] FIG. 26 is a perspective view illustrating an anchor
deflecting mandrel member;
[0070] FIG. 27 is a perspective view of an insulating ring for
insulating the hypotube electrodes from the anchors;
[0071] FIG. 28 is a cross-sectional view of an insulating ring for
insulating the hypotube electrodes from the anchors along lines
28-28 of FIG. 27;
[0072] FIG. 29 is a side view of the insulating ring for insulating
the hypotube electrodes from the anchors;
[0073] FIG. 30 is a perspective view illustrating the anchor push
tube;
[0074] FIG. 31 is a side plan view illustrating the anchor push
tube in accordance with the present invention;
[0075] FIG. 32 is partially cross-sectional view, similar to FIG. 1
illustrating the inventive instrument with anchors and hypotubes
deployed;
[0076] FIG. 33 is a detail perspective view illustrating deployment
of anchors and hypotube ablation stylets; and
[0077] FIG. 34 is a detail perspective view similar to FIG. 33
illustrating full deployment of hypotubes and anchors in an
alternative embodiment of the invention.
DETAILED DESCRIPTION OF THE BEST MODE
[0078] Referring to FIG. 1, an ablation instrument 10 constructed
in accordance with the present invention is illustrated. Instrument
10 comprises a catheter portion 12 and a handle portion 14.
Ablation instrument 10 is illustrated with one of the two mating
handle halves removed and partially in cross section, in order to
reveal its internal parts and workings in connection with the
following description.
[0079] Referring to FIGS. 1 and 2, the inventive ablation
instrument 10 is illustrated in the fully retracted position
suitable for advancement of catheter portion 12 into tissue, for
example, tissue to be subjected to ablation by being treated with
radiofrequency energy. In this position, the catheter 12 present a
simple thin smooth pointed surface well-suited to penetrate healthy
tissue while doing minimal damage. At the same time, the sharpness
of the point and the relatively stiff, though somewhat flexible,
nature of catheter 12 enables accurate steering of the point and
control of the path of penetration. In the case of the treatment of
uterine fibroids, such steering is achieved largely by manipulation
of the uterus coupled with advancement of the catheter 12.
[0080] Handle portion 14 includes a pair of actuators namely a
stylet actuator 16 and an anchoring actuator 18. Stylet actuator 16
includes a serrated surface 20. Anchoring actuator 18 includes a
pair of serrated surfaces, namely an anchor retraction surface 22
and an anchor deployment surface 24. The application of relatively
great force is facilitated by a wall 26, against which the thumb or
other finger of the surgeon may bear during the respective
deployment and retraction phase of an operation performed using the
inventive ablation instrument 10.
[0081] Stylet actuator 16 and anchoring actuator 18 are supported
within handle portion 14. Handle portion 14 comprises a left
housing half 28 and a right housing half 30 symmetrical in shape to
left housing half 28, as illustrated in FIG. 2.
[0082] As illustrated in FIGS. 1, 3 and 4, the inventive ablation
instrument may be configured in the undeployed state.
Alternatively, as illustrated in FIGS. 2, 5, 6 and 7, the inventive
ablation instrument 10 may be configured either the anchors or the
ablation stylets in a deployed state, or as illustrated in FIGS. 2,
5, 6 and 7 with anchors and stylets both fully deployed.
[0083] Referring to FIG. 7, ablation instrument 10 is terminated in
a trocar 32, which defines a pointed tip 34. Trocar 32 also
functions as an electrode mandrel to deflect the tissue ablation
stylets in various directions, as appears more fully below. Trocar
32 is illustrated in FIGS. 8-12. Trocar 32 has a pointed tip 34,
defined by bottom surface 36 and side surfaces 38 and 40, as
illustrated most clearly in FIG. 8. Surfaces 36, 38 and 40 ground
into the distal portion 42 of trocar 32. Trocar 32 also includes a
central channel 44 which extends through the length of trocar 32
and is centered on the central axis of trocar 32.
[0084] A plurality of deflection surfaces 46 are positioned at the
end of longitudinal grooves 48, as illustrated in FIG. 9. These
surfaces 46 are configured to gently bend the flexible hypotubes
which are excited with radiofrequency energy during the ablation of
uterine fibroid tissue, causing them to exit catheter 12 and follow
substantially straight paths through the tissue to be ablated.
During this deflection, the action of deflection surfaces 46 is
complemented by the inside curved surface 50 of insulative Teflon
deflector ring 52.
[0085] In accordance with an especially preferred embodiment of the
invention, stylets 54 are made of a nickel titanium alloy instead
of stainless steel. In this case, the configuration of deflection
surfaces 46 is shaped to maximize the deflection without over
straining the nickel titanium alloy material of the stylets. More
particularly, in accordance with the preferred embodiment of the
invention, surfaces 46 are configured to result in a strain less
than eight percent. Strains in the range of 2%-8% will work with
strains in the range of about 4%, for example 3.5% to 4.5%,
representing an easy to implement commercial solution. Less than 2%
strain does not provide appreciable bending with today's
technology. Higher performance may be obtained by maintaining a
deflection angle which results in a strain of 6-7%. Configuring
surface 46 to result in strains approaching 8%, for example 7.5%
will maximize deflection and flexibility in design of ablation
volume, but will tend to result in quicker degradation of hypotube
stylets 54. However, if a particular procedure does not involve a
great number of ablations, or the use of several disposable
ablation catheters 10 is acceptable, such devices under certain
circumstances do present advantages.
[0086] The deflection of a plurality of hypotubes 54 is illustrated
in FIG. 7. Hypotubes 54 are flexible hollow tubes made of steel or
nickel titanium alloy. Hypotubes 54, as well as all other steel
parts of the inventive ablation device 10, are preferably, for
economic and/or performance reasons, made of stainless steel or
other high quality steel, except as indicated herein. The tubes
define an internal volume 56 which contains a wire thermocouple,
which performs the function of measuring the temperature of the
ablated tissue which, over time, allows control of the ablation
operation and ensures that the ablated tissue will become necrotic.
In FIG. 7, the thermocouples 56 are shown in only one of the tubes
for purposes of clarity of illustration.
[0087] Hypotubes 54 slidably move in longitudinal grooves 48.
Hypotubes 54, which function as ablation electrodes, are mounted on
a needle core 58, illustrated in FIGS. 13-15. Needle core 58
includes a plurality of longitudinal grooves 60. Each of six
hypotubes 54 is mounted in its respective longitudinal groove 60
and secured in groove 60 by friction or through the use of an
adhesive. A seventh hypotube 62 is mounted in a central axial bore
64. The assembly of hypotubes 54 and 62 in needle core 58 is
illustrated in FIGS. 16-18. The mounting of hypotubes 54 in needle
core 58 is illustrated most clearly in perspective in FIG. 19.
[0088] As illustrated most clearly in FIG. 20, hypotubes 54 are
preferably oriented with the flat surfaces 65 of their points
oriented to slidingly cooperate with deflection surfaces 46 during
deployment of the hypotubes. This is done by having the pointed
tips of hypotubes 54 radially displaced from the center of catheter
12, which prevents the pointed tips of the hypotubes from digging
into deflection surfaces 46.
[0089] A flexible steel electrode push tube 66 is disposed around
and secured to needle core 58 with the needles mounted in it.
Sliding movement of the hypotubes 54 in longitudinal grooves 48 is
achieved by movement of electrode push tube 66. Movement in
direction 68 causes the deployment of hypotubes 54 and 62. Movement
in direction 70 causes retraction of the hypotubes.
[0090] Referring to FIGS. 5 and 7, a flexible steel electrode
mandrel tube 74 is disposed around and over electrode push tube 66.
Flexible steel electrode mandrel tube 74 allows electrode push tube
66 to freely slide within it. This is achieved, despite the
relatively large area of the tubes, because the facing surfaces of
the tubes are both smooth and because there is a small gap between
their facing surfaces, thus minimizing friction. Such gaps allow
provision for flushing the instrument clean with water, as is done
with prior art devices. A flexible plastic tubular insulative
member 76 is disposed around and over electrode mandrel tube
74.
[0091] Insulative member 76 isolates electrical radiofrequency
ablation energy (carried by push tube 66 for exciting hypotubes 54
and 62) from anchor push tube 78. This allows electrical ablation
energy to be optionally applied to anchor push tube 78 to
independently cause the anchors 80 on anchor member 82 to apply
ablation energy to a different volume than that which is ablated by
the electrode stylets 54 and 62. Anchor member 82 is illustrated in
FIGS. 21-23. Anchors 80 are cut using a laser from a steel tube to
form steel anchor member 82. Each anchor 80 has a tip 84 which is
bent radially outwardly to facilitate deflection over anchor
mandrel 86 in response to movement of anchor member 82 in the
direction of arrow 70.
[0092] Anchor mandrel 86 is illustrated in FIGS. 24-26. Anchor
mandrel 86 incorporates a number of deflection surfaces 88, as
illustrated most clearly in FIGS. 7 and 26. In accordance with an
especially preferred embodiment of the invention, anchor member 82,
and thus anchors 80, are made of a nickel titanium alloy instead of
stainless steel. Nickel titanium alloy is a preferred material for
both anchors 80 and stylets 54.
[0093] The configuration of deflection surfaces 88 is shaped to
maximize the deflection without over-straining the nickel titanium
alloy material of the anchors. More particularly, in accordance
with the preferred embodiment of the invention, surfaces 88 are
configured to result in a strain less than eight percent. Strains
in the range of 2-8% will work with strains in the range of about
4%, for example 3.5 to 4.5%, are less rigorously 3% to 5%,
representing an easy to implement commercial solution. Higher
performance may be obtained by maintaining a deflection angle which
results in a strain of 6-7%. Configuring surface 88 to result in
strains approaching 8%, for example 7.5% will maximize deflection
and flexibility in design of ablation volume, but will tend to
result in quicker degradation of anchors 80. However, if a
particular procedure does not involve a great number of ablations,
or the use of several disposable ablation catheters 10 is
acceptable, such devices under certain circumstances do present
advantages.
[0094] The structure of the distal end of catheter portion 12 is
completed by a steel anchor cover 90, which is supported on,
surrounds and is secured to insulating ring 52 whose structure is
illustrated in FIGS. 27-29. During deflection, anchors 80 pass
between deflection surfaces 88 and the inside surface of steel
anchor cover 90.
[0095] Anchor push tube 78, illustrated in FIGS. 30 and 31 includes
a pair of keys 92 which are shaped like the letter T. Keys 92 mate
with slots 94 in anchor member 82. Anchor member 82 and anchor push
tube 78 thus act as a unitary member during deployment and
retraction of anchors 80, in response to sliding motion of anchor
member 82 and anchor push tube 78.
[0096] The structure of catheter 12 is completed by outer tube 96
which is secured to handle 14 at one end and secured to a tubular
slip ring 98 which slides over anchor push tube 78.
[0097] FIG. 1 illustrates the relative positions of anchoring
actuator 18, and stylet actuator 16 before deployment of anchors
and stylets. This corresponds to FIG. 4.
[0098] Electrode mandrel tube 74 is secured at its proximal end to
handle 14. At its distal end, electrode mandrel tube 74 is secured
to trocar 32, for example by a quantity of epoxy adhesive 100 in
the annular groove 102 on trocar 32, as illustrated in FIG. 3.
Stylet actuator 16 is secured to electrode push tube 66. Thus,
movement in the direction of arrow 68 in FIG. 1 causes the stylets
to emerge from the end of the catheter as illustrated in FIGS. 5,
6, 7 and 32. Full deployment of ablation electrodes or stylets 54
and 62 is illustrated most clearly in FIG. 33.
[0099] Anchoring actuator 18 is secured to anchor push tube 78. At
its distal end, electrode mandrel tube 74 is secured to anchor
mandrel 86, for example by a quantity of epoxy adhesive.
Accordingly, movement of anchoring actuator 18, in the direction of
arrow 70 in FIG. 1, causes the anchors 80 to emerge from the
catheter as illustrated in FIGS. 5, 6, 7 and 32. Full deployment of
anchors 80 is illustrated most clearly in FIG. 33.
[0100] In accordance with the present invention it is contemplated
that control of the inventive ablation device 10 will be achieved
by one or two electrical switches 104 and 106. Operation of switch
106 will cause the appearance of a menu on a display, for example
by axial movement of switch 106 in the manner of a joystick.
Transverse movement of switch 106 causes the menu to switch between
different menu items, such as controlling ablation time,
controlling ablation temperature, or some other parameter.
Selection of the desired value for the selected parameter is
achieved by transverse motion of switch 106, causing the various
values to be displayed on the display. When the desired value is
seen on the screen by the surgeon, depression of switch 104
registers that value with the electronic circuit controlling
ablation and causes the inventive ablation device 10 to be operated
in accordance with the selected parameter.
[0101] RF ablation energy, control signals, and temperature
measurement signals are coupled from the inventive ablation device
10 to a control unit/RF energy source by a connector 108. In
accordance with the present invention, it is contemplated that a
conventional radiofrequency energy source such as that used in
conventional ablation systems would be employed in conjunction with
the inventive ablation device 10.
[0102] In accordance with the present invention, cauterization
radiofrequency energy may also be applied to trocar 32 during
withdrawal of trocar 32 from the patient in order to control loss
of blood. It is noted that the nature of the RF signal needed to
achieve cautery is different from the nature of an ablation signal.
Both of these signals are well defined in the art. Likewise, their
generation is also well-known. However, in accordance of the
present invention conventional cautery and conventional ablation
signals may be used for cautery and ablation, respectively.
[0103] An alternative embodiment of the inventive catheter 112 is
illustrated in FIG. 34. Here anchors 180 are positioned distally of
ablation electrodes 154.
[0104] While the inventive device has been illustrated for use in
the ablation of uterine fibroids, it is understood that this
particular implementation is exemplary and that the inventive
device may be employed in a wide variety of circumstances Likewise,
while an illustrative embodiment of the invention has been
described, it is understood that various modifications to the
structure of the disclosed device will be obvious to those of
ordinary skill in the art. Such modifications are within the spirit
and scope of the invention which is limited and defined only by the
appended claims.
* * * * *