U.S. patent application number 13/777523 was filed with the patent office on 2013-11-14 for tissue modification devices and methods of using the same.
The applicant listed for this patent is Trice Orthopedics, Inc.. Invention is credited to James S. Cybulski, Fred R. Seddiqui.
Application Number | 20130303846 13/777523 |
Document ID | / |
Family ID | 41569256 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130303846 |
Kind Code |
A1 |
Cybulski; James S. ; et
al. |
November 14, 2013 |
TISSUE MODIFICATION DEVICES AND METHODS OF USING THE SAME
Abstract
Tissue modification devices are provided. Aspects of the devices
include an elongated member having a proximal end and a distal end.
The distal end of the elongated member is dimensioned to pass
through a minimally invasive body opening and includes a distal end
integrated visualization sensor and tissue modifier. In some
instances, the devices further include an integrated articulation
mechanism that imparts steerability to at least one of the
visualization sensor, the tissue modifier and the distal end of the
elongated member. Also provided are methods of modifying internal
target tissue of a subject using the tissue modification
devices.
Inventors: |
Cybulski; James S.; (Menlo
Park, CA) ; Seddiqui; Fred R.; (Los Altos,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Trice Orthopedics, Inc. |
King of Prussia |
PA |
US |
|
|
Family ID: |
41569256 |
Appl. No.: |
13/777523 |
Filed: |
February 26, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12422176 |
Apr 10, 2009 |
|
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13777523 |
|
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|
|
61082774 |
Jul 22, 2008 |
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Current U.S.
Class: |
600/104 |
Current CPC
Class: |
A61B 2018/00982
20130101; A61B 2218/007 20130101; A61B 1/0684 20130101; A61B
2218/002 20130101; A61B 1/00087 20130101; A61B 1/00167 20130101;
A61B 1/015 20130101; A61B 2018/1407 20130101; A61B 1/00183
20130101; A61B 2017/00261 20130101; A61B 1/00114 20130101; A61B
1/05 20130101; A61B 90/361 20160201; A61B 2017/320069 20170801;
A61B 1/0676 20130101; A61B 2017/32007 20170801; A61B 18/1485
20130101; A61B 2090/306 20160201; A61B 1/07 20130101; A61B 1/317
20130101; A61B 1/00091 20130101; A61B 1/3135 20130101; A61B 1/00071
20130101; A61B 1/051 20130101; A61B 1/012 20130101; A61B
2017/320071 20170801 |
Class at
Publication: |
600/104 |
International
Class: |
A61B 1/012 20060101
A61B001/012 |
Claims
1. A tissue modification device comprising: an elongated member
having a distal end dimensioned to be passed through a minimally
invasive body opening, wherein the distal end comprises an
integrated visualization sensor and tissue modifier.
2. The tissue modification device according to claim 1, wherein the
integrated visualization sensor comprises a lens and an integrated
circuit.
3. The tissue modification device according to claim 2, wherein the
visualization sensor is a CMOS device.
4. The tissue modification device according to claim 2, wherein the
visualization sensor is a CCD device.
5. The tissue modification device according to claim 1, wherein the
device further comprises an integrated articulation mechanism that
imparts steerability to at least one of the visualization sensor,
the tissue modifier and the distal end of the elongated member.
6. The tissue modification device according to claim 1, wherein the
distal end of the elongate member is dimensioned to be passed
through a Cambin's triangle.
7. The tissue modification device according to claim 6, wherein the
distal end of the elongate member has an outer diameter of 7.5 mm
or less.
8. The tissue modification device according to claim 7, wherein the
distal end of the elongate member has an outer diameter of 7.0 mm
or less.
9. The tissue modification device according of claim 8, wherein the
distal end of the elongate member has an outer diameter of 5.0 mm
or less.
10. The tissue modification device according to claim 1, wherein
the distal end of the elongate member further comprises an
integrated illuminator.
11. The tissue modification device according to claim 10, wherein
the illuminator is a fiber-optic illuminator.
12. The tissue modification device according to claim 10, wherein
the illuminator is a light emitting diode.
13. The tissue modification device according to claim 1, wherein
the tissue modifier comprises an electrode.
14. The tissue modification device according to claim 1, wherein at
least one of the visualization sensor and tissue modifier are
moveable relative to the distal end of the elongate member.
15. The tissue modification device according to claim 1, wherein
the distal end of the elongate member further comprises an
irrigator and an aspirator.
16. The tissue modification device according to claim 15, wherein
the aspirator is located proximal of the integrated visualization
sensor.
17. The tissue modification device according to claim 15, wherein
the aspirator comprises a port having a cross-sectional area that
is 33% or more of the cross-sectional area of the distal end of the
elongate member.
18. The tissue modification device according to claim 1, wherein
the elongated member is rigid.
19. The tissue modification device according to claim 1, wherein
the tissue modification device is configured to modify an
intervertebral disc tissue.
20. The tissue modification device according to claim 1, wherein
the device is configured as a disposable.
21. The tissue modification device according to claim 1, wherein
the device comprises an operating handle positioned at the proximal
end.
22. The tissue modification device according to claim 21, wherein
the distal end of the elongated member is rotatable about its
longitudinal axis when a significant portion of the operating
handle is maintained in a fixed position.
23. A system comprising: (a) an elongated member having a distal
end dimensioned to be passed through a minimally invasive body
opening, wherein the distal end comprises an integrated
visualization sensor and tissue modifier; and (b) an extracorporeal
controller operatively coupled to the proximal end of the elongated
member.
24. The system according to claim 23, wherein the system further
comprises an image displayer for displaying to a user images
obtained by the visualization sensor.
25. The system according to claim 23, wherein the system further
comprises a minimally invasive access tube.
26. A method of modifying an internal target tissue of a subject,
the method comprising: (a) positioning distal end of a tissue
modification device comprising an elongated member having a distal
end dimensioned to be passed through a minimally invasive body
opening, wherein the distal end comprises an integrated
visualization sensor and tissue modifier in operable relation to
the internal target tissue; and (b) modifying the internal target
tissue with the tissue modifier.
27. The method according to claim 26, wherein the internal target
tissue site comprises spinal tissue.
28. The method according to claim 26, wherein the method is a
method of removing nucleus pulposus tissue from an intervertebral
disc.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation application of U.S.
patent application Ser. No. 12/422,176, filed Apr. 10, 2009, which
claims the priority benefit under 35 U.S.C. .sctn.119(e) of U.S.
Provisional Application No. 61/082,774, filed Jul. 22, 2008, the
entireties of both of which are hereby incorporated by reference
herein.
INTRODUCTION
[0002] Traditional surgical procedures, both therapeutic and
diagnostic, for pathologies located within the body can cause
significant trauma to the intervening tissues. These procedures
often require a long incision, extensive muscle stripping,
prolonged retraction of tissues, denervation and devascularization
of tissue. These procedures can require operating room time of
several hours and several weeks of post-operative recovery time due
to the destruction of tissue during the surgical procedure. In some
cases, these invasive procedures lead to permanent scarring and
pain that can be more severe than the pain leading to the surgical
intervention.
[0003] The development of percutaneous procedures has yielded a
major improvement in reducing recovery time and post-operative pain
because minimal dissection of tissue, such as muscle tissue, is
required. For example, minimally invasive surgical techniques are
desirable for spinal and neurosurgical applications because of the
need for access to locations within the body and the danger of
damage to vital intervening tissues. While developments in
minimally invasive surgery are steps in the right direction, there
remains a need for further development in minimally invasive
surgical instruments and methods.
SUMMARY
[0004] Tissue modification devices are provided. Aspects of the
devices include an elongated member having a proximal end and a
distal end. The distal end of the elongated member is dimensioned
to pass through a minimally invasive body opening and includes a
distal end integrated visualization sensor and tissue modifier. In
some instances, the devices further include an integrated
articulation mechanism that imparts steerability to at least one of
the visualization sensor, the tissue modifier and the distal end of
the elongated member. Also provided are methods of modifying
internal target tissue of a subject using the tissue modification
devices.
BRIEF DESCRIPTION OF THE FIGURES
[0005] FIGS. 1A and B provide two different views of a disposable
tissue modification device according to an embodiment of the
invention.
[0006] FIGS. 2A to 2C provide cross-sectional views of the distal
ends of devices according to certain embodiments of the
invention.
[0007] FIGS. 3A to 3E provide cross-sectional views of the distal
ends of devices according to certain embodiments of the
invention.
[0008] FIG. 4 provides an alternative view of the distal end of a
device according to an embodiment of the invention, where the
device is shown accessing the nucleus pulposus of an intervertebral
disc.
[0009] FIG. 5 provides an alternative view of the distal end of a
device according to an embodiment of the invention, where the
device is shown accessing the nucleus pulposus of an intervertebral
disc.
[0010] FIGS. 6A to 6E provide various views of the distal end of a
device according to one embodiment of the invention.
[0011] FIG. 7 provides a cutaway view of the device shown in FIGS.
1A and 1B.
[0012] FIG. 8 provides a depiction of a system according to one
embodiment of the invention, where the system includes both a
disposable tissue modifier device and an extra-corporeal control
unit.
[0013] FIG. 9 provides a block diagram showing the architecture of
a system according to one embodiment of the invention and how that
system interacts with a user.
[0014] FIG. 10 shows a CMOS visualization sub-system that may be
incorporated into a tissue modification system according to an
embodiment of the invention.
DETAILED DESCRIPTION
[0015] Tissue modification devices are provided. Aspects of the
devices include an elongated member having a proximal end and a
distal end. The distal end of the elongated member is dimensioned
to pass through a minimally invasive body opening and includes a
distal end integrated visualization sensor and tissue modifier. In
some instances, the devices further include an integrated
articulation mechanism that imparts steerability to at least one of
the visualization sensor, the tissue modifier and the distal end of
the elongated member. Also provided are methods of modifying
internal target tissue of a subject using the tissue modification
devices.
[0016] Before the present invention is described in greater detail,
it is to be understood that this invention is not limited to
particular embodiments described, as such may, of course, vary. It
is also to be understood that the terminology used herein is for
the purpose of describing particular embodiments only, and is not
intended to be limiting, since the scope of the present invention
will be limited only by the appended claims.
[0017] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limit of that range and any other stated or intervening
value in that stated range, is encompassed within the invention.
The upper and lower limits of these smaller ranges may
independently be included in the smaller ranges and are also
encompassed within the invention, subject to any specifically
excluded limit in the stated range. Where the stated range includes
one or both of the limits, ranges excluding either or both of those
included limits are also included in the invention.
[0018] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can also be used in the practice or testing of the present
invention, representative illustrative methods and materials are
now described.
[0019] All publications and patents cited in this specification are
herein incorporated by reference as if each individual publication
or patent were specifically and individually indicated to be
incorporated by reference and are incorporated herein by reference
to disclose and describe the methods and/or materials in connection
with which the publications are cited. The citation of any
publication is for its disclosure prior to the filing date and
should not be construed as an admission that the present invention
is not entitled to antedate such publication by virtue of prior
invention. Further, the dates of publication provided may be
different from the actual publication dates which may need to be
independently confirmed.
[0020] It is noted that, as used herein and in the appended claims,
the singular forms "a", "an", and "the" include plural referents
unless the context clearly dictates otherwise. It is further noted
that the claims may be drafted to exclude any optional element. As
such, this statement is intended to serve as antecedent basis for
use of such exclusive terminology as "solely," "only" and the like
in connection with the recitation of claim elements, or use of a
"negative" limitation.
[0021] As will be apparent to those of skill in the art upon
reading this disclosure, each of the individual embodiments
described and illustrated herein has discrete components and
features which may be readily separated from or combined with the
features of any of the other several embodiments without departing
from the scope or spirit of the present invention. Any recited
method can be carried out in the order of events recited or in any
other order which is logically possible.
[0022] In further describing various aspects of the invention,
aspects of embodiments of the subject tissue modification devices
are described first in greater detail. Next, embodiments of methods
of modifying an internal target tissue of a subject in which the
subject tissue modification devices may find use are reviewed in
greater detail.
Tissue Modification Devices
[0023] Aspects of the invention include tissue modification devices
useful for modifying an internal target tissue site, e.g., a spinal
location that is near or inside of an intervertebral disc (IVD). As
summarized above, the tissue modification devices are dimensioned
such that at least the distal end of the devices can pass through a
minimally invasive body opening. As such, at least the distal end
of the devices may be introduced to an internal target site of a
patient, e.g., a spinal location that is near or inside of an
intervertebral disc, through a minimal incision, e.g., one that is
less than the size of an incision employed for an access device
having a outer diameter of 20 mm or smaller, e.g., less than 75%
the size of such an incision, such as less than 50% of the size of
such an incision, or smaller. In some instances, at least the
distal end of the elongated member is dimensioned to pass through a
Cambin's triangle. The Cambin's triangle (also known in the art as
the Pambin's triangle) is an anatomical spinal structure bounded by
an exiting nerve root and a traversing nerve root and a disc. The
exiting root is the root that leaves the spinal canal just cephalad
(above) the disc, and the traversing root is the root that leaves
the spinal canal just caudad (below) the disc. Where the distal end
of the elongated member is dimensioned to pass through a Cambin's
triangle, at least the distal end of the device has a longest
cross-sectional dimension that is 10 mm or less, such as 8 mm or
less and including 7 mm or less. In some instances, the elongated
member has an outer diameter that is 7.5 mm or less, such as 7.0 mm
or less, including 6.7 mm or less, such as 6.6 mm or less, 6.5 mm
or less, 6.0 mm or less, 5.5 mm or less, 5.0 mm or less.
[0024] As summarized above, tissue modification devices of the
invention include an elongated member. As this component of the
devices is elongated, it has a length that is 1.5 times or longer
than its width, such as 2 times or longer than its width, including
5 or even 10 times or longer than its width, e.g., 20 times longer
than its width, 30 times longer than its width, or longer. The
length of the elongated member may vary, an in some instances
ranges from 5 cm to 20 cm, such as 7.5 cm to 15 cm and including 10
to 12 cm. The elongated member may have the same outer
cross-sectional dimensions (e.g., diameter) along its entire
length. Alternatively, the cross-sectional diameter may vary along
the length of the elongated member.
[0025] The elongated members of the subject tissue modification
devices have a proximal end and a distal end. The term "proximal
end", as used herein, refers to the end of the elongated member
that is nearer the user (such as a physician operating the device
in a tissue modification procedure), and the term "distal end", as
used herein, refers to the end of the elongated member that is
nearer the internal target tissue of the subject during use. The
elongated member is, in some instances, a structure of sufficient
rigidity to allow the distal end to be pushed through tissue when
sufficient force is applied to the proximal end of the elongate
member. As such, in these embodiments the elongated member is not
pliant or flexible, at least not to any significant extent.
[0026] Depending on the particular device embodiment, the elongated
member may or may not include one or more lumens that extend at
least partially along its length. When present, the lumens may vary
in diameter and may be employed for a variety of different
purposes, such as irrigation, aspiration, electrical isolation (for
example of conductive members, such as wires), as a mechanical
guide, etc., as reviewed in greater detail below. When present,
such lumens may have a longest cross section that varies, ranging
in some in stances from 0.5 to 5.0 mm, such as 1.0 to 4.5 mm,
including 1.0 to 4.0 mm. The lumens may have any convenient
cross-sectional shape, including but not limited to circular,
square, rectangular, triangular, semi-circular, trapezoidal,
irregular, etc., as desired. These lumens may be provided for a
variety of different functions, including as irrigation and/or
aspiration lumens, as described in greater detail below.
[0027] As summarized above, the devices include a distal end
integrated visualization sensor and a distal end integrated tissue
modifier. As the visualization sensor is integrated at the distal
end of the device, it cannot be removed from the remainder of the
device without significantly compromising the structure and
functionality of the device. Accordingly, the devices of the
present invention are distinguished from devices which include a
"working channel" through which a separate autonomous device, such
as a tissue modifier, is passed through. In contrast to such
devices, since the visualization sensor of the present device is
integrated at the distal end, it is not a separate device from the
elongated member that is merely present in a working channel of the
elongated member and which can be removed from the working channel
of such an elongated member without structurally compromising the
elongated member in any way. The visualization sensor may be
integrated with the distal end of the elongated member by a variety
of different configurations. Integrated configurations include
configurations where the visualization sensor is fixed relative to
the distal end of the elongated member, as well as configurations
where the visualization sensor is movable to some extent relative
to the distal end of the elongated member. Movement of the
visualizations sensor may also be provided relative to the distal
end of the elongated member, but then fixed with respect to another
component present at the distal end, such as a distal end
integrated tissue modifier. Specific configurations of interest are
further described below in connection with the figures.
[0028] Visualization sensors of interest include miniature imaging
sensors that have a cross-sectional area which is sufficiently
small for its intended use and yet retains a sufficiently high
matrix resolution. Imaging sensors of interest are those that
include a photosensitive component, e.g., array of photosensitive
elements that convert light into electrons, coupled to an
integrated circuit. The integrated circuit may be configured to
obtain and integrate the signals from the photosensitive array and
output image data, which image data may in turn be conveyed to an
extra-corporeal device configured to receive the data and display
it to a user. The image sensors of these embodiments may be viewed
as integrated circuit image sensors. The integrated circuit
component of these sensors may include a variety of different types
of functionalities, including but not limited to: image signal
processing, memory, and data transmission circuitry to transmit
data from the visualization sensor to an extra-corporeal location,
etc. The miniature imaging sensors may further include a lens
component made up of one or more lenses positioned relative to the
photosensitive component so as to focus images on the
photosensitive component. Where desired, the one or more lenses may
be present in a housing. Specific types of miniature imaging
sensors of interest include complementary metal-oxide-semiconductor
(CMOS) sensors and charge-coupled device (CCD) sensors. The sensors
may have any convenient configuration, including circular, square,
rectangular, etc. Visualization sensors of interest may have a
longest cross-sectional dimension that varies depending on the
particular embodiment, where in some instances the longest cross
sectional dimension (e.g., diameter) is 4.0 mm or less, such as 3.5
mm or less, including 3.0 mm or less, such as 2.5 mm or less,
including 2.0 mm or less, including 1.5 mm or less, including 1.0
mm or less.
[0029] Imaging sensors of interest may be either frontside or
backside illumination sensors, and have sufficiently small
dimensions while maintaining sufficient functionality to be
integrated at the distal end of the elongated members of the
devices of the invention. Aspects of these sensors are further
described in one or more the following U.S. patents, the
disclosures of which are herein incorporated by reference: U.S.
Pat. Nos. 7,388,242; 7,368,772; 7,355,228; 7,345,330; 7,344,910;
7,268,335; 7,209,601; 7,196,314; 7,193,198; 7,161,130; and
7,154,137.
[0030] As the visualization sensor is a distal end integrated
visualization sensor, it is located at or near the distal end of
the elongated member. Accordingly, it is positioned at 3 mm or
closer to the distal end, such as at 2 mm or closer to the distal
end, including at 1 mm or closer to the distal end. In some
instances, the visualization sensor is located at the distal end of
the elongated member. The visualization sensor may provide for
front viewing and/or side-viewing, as desired. Accordingly, the
visualization sensor may be configured to provide image data as
seen in the forward direction from the distal end of the elongated
member. Alternatively, the visualization sensor may be configured
to provide image data as seen from the side of the elongate member.
In yet other embodiments, a visualization sensor may be configured
to provide image data from both the front and the side, e.g., where
the image sensor faces at an angle that is less than 90.degree.
relative to the longitudinal axis of the elongated member, e.g., as
illustrated in FIGS. 6A to 6C, described in greater detail
below.
[0031] Because the visualization sensor is a distal end integrated
visualization sensor, the visualization sensor also includes
functionality for conveying image data to an extra-corporeal
device, such as an image display device. In some instances, a
signal cable (or other type of signal conveyance element) may be
present to connect the image sensor at the distal end to a device
at the proximal end of the elongate member, e.g., in the form of
one or more wires running along the length of the elongate member
from the distal to the proximal end. Alternatively, wireless
communication protocols may be employed, e.g., where the imaging
sensor is operatively coupled to a wireless data transmitter, which
may be positioned at the distal end of the elongated member
(including integrated into the visualization sensor, at some
position along the elongated member or at the proximal end of the
device, e.g., at a location of the proximal end of the elongated
member or associated with the handle of the device).
[0032] Where desired, the devices may include one or more
illumination elements configured to illuminate a target tissue
location so that the location can be visualized with a
visualization sensor, e.g., as described above. A variety of
different types of light sources may be employed as illumination
elements, so long as their dimensions are such that they can be
positioned at the distal end of the elongated member. The light
sources may be integrated with a given component (e.g., elongated
member) such that they are configured relative to the component
such that the light source element cannot be removed from the
remainder of the component without significantly compromising the
structure of the component. As such, the integrated illumination
element of these embodiments is not readily removable from the
remainder of the component, such that the illumination element and
remainder of the component form an inter-related whole. The light
sources may be light emitting diodes configured to emit light of
the desired wavelength range, or optical conveyance elements, e.g.,
optical fibers, configured to convey light of the desired
wavelength range from a location other than the distal end of the
elongate member, e.g., a location at the proximal end of the
elongate member, to the distal end of the elongate member. As with
the image sensors, the light sources may include a conductive
element, e.g., wire, or an optical fiber, which runs the length of
the elongate member to provide for power and control of the light
sources from a location outside the body, e.g., an extracorporeal
control device. Where desired, the light sources may include a
diffusion element to provide for uniform illumination of the target
tissue site. Any convenient diffusion element may be employed,
including but not limited to a translucent cover or layer
(fabricated from any convenient translucent material) through which
light from the light source passes and is thus diffused. In those
embodiments of the invention where the system includes two or more
illumination elements, the illumination elements may emit light of
the same wavelength or they may be spectrally distinct light
sources, where by "spectrally distinct" is meant that the light
sources emit light at wavelengths that do not substantially
overlap, such as white light and infra-red light. In certain
embodiments, an illumination configuration as described in
copending U.S. application Ser. Nos. 12/269,770 and 12/269,772 (the
disclosures of which are herein incorporated by reference) is
present in the device.
[0033] In addition to a distal end integrated visualization sensor,
devices of the invention further include an integrated distal end
tissue modifier. As the tissue modifier is integrated at the distal
end of the device, it cannot entirely be removed from the remainder
of the device without significantly compromising the structure and
functionality of the device. While the tissue modifier cannot
entirely be removed from the device without compromising the
structure and functionality of the device, components of the tissue
modifier may be removable and replaceable. For example, an RF
electrode tissue modifier may be configured such that the wire
component of the tissue modifier may be replaceable while the
remainder of the tissue modifier is not. Accordingly, the devices
of the present invention are distinguished from devices which
include a "working channel" through which a separate autonomous
tissue modifier device, such as autonomous RF electrode device, is
passed through. In contrast to such devices, since the tissue
modifier of the present device is integrated at the distal end, it
is not a separate device from the elongated member that is merely
present in a working channel of the elongated member and which can
be removed from the working channel of such an elongated member
without structurally compromising the elongated member in any way.
The tissue modifier may be integrated with the distal end of the
elongated member by a variety of different configurations.
Integrated configurations include configurations where the tissue
modifier is fixed relative to the distal end of the elongated
member, as well as configurations where the tissue modifier is
movable to some extent relative to the distal end of the elongated
member may be employed in devices of the invention. Specific
configurations of interest are further described below in
connection with the figures. As the tissue modifier is a distal end
integrated tissue modifier, it is located at or near the distal end
of the elongated member. Accordingly, it is positioned at 10 mm or
closer to the distal end, such as at 5 mm or closer to the distal
end, including at 2 mm or closer to the distal end. In some
instances, the tissue modifier is located at the distal end of the
elongated member.
[0034] Tissue modifiers are components that interact with tissue in
some manner to modify the tissue in a desired way. The term modify
is used broadly to refer to changing in some way, including cutting
the tissue, ablating the tissue, delivering an agent(s) to the
tissue, freezing the tissue, etc. As such, of interest as tissue
modifiers are tissue cutters, tissue ablators, tissue
freezing/heating elements, agent delivery devices, etc. Tissue
cutters of interest include, but are not limited to: blades, liquid
jet devices, lasers and the like. Tissue ablators of interest
include, but are not limited to ablation devices, such as devices
for delivery ultrasonic energy (e.g., as employed in ultrasonic
ablation), devices for delivering plasma energy, devices for
delivering radiofrequency (RF) energy, devices for delivering
microwave energy, etc. Energy transfer devices of interest include,
but are not limited to: devices for modulating the temperature of
tissue, e.g., freezing or heating devices, etc. In some
embodiments, the tissue modifier is not a tissue modifier that
achieves tissue modification by clamping, clasping or grasping of
tissue such as may be accomplished by devices that trap tissue
between opposing surfaces (e.g., jaw-like devices). In these
embodiments, the tissue modification device is not an element that
is configured to apply mechanical force to tear tissue, e.g., by
trapping tissue between opposing surfaces. In some embodiments,
tissue modification comprises an action other than just removal by
low pressure irrigation or aspiration, for example where some other
act is performed on the tissue beyond low pressure irrigation
and/or aspiration. In some embodiments, the tissue modifier is
distinct from a probe element or device that is configured to move
tissue without any modification to the tissue other than simple
displacement or repositioning, such as through retraction,
atraumatic movement, etc.
[0035] In some instances, the tissue modifier includes at least one
electrode. For example, tissue modifiers of interest may include RF
energy tissue modifiers, which include at least one electrode and
may be configured in a variety of different ways depending on the
desired configuration of the RF circuit. An RF circuit can be
completed substantially entirely at target tissue location of
interest (bipolar device) or by use of a second electrode attached
to another portion of the patient's body (monopolar device). In
either case, a controllable delivery of RF energy is achieved.
Aspects of the subject tissue modification devices include a
radiofrequency (RF) electrode positioned at the distal end of the
elongated member. RF electrodes are devices for the delivery of
radiofrequency energy, such as ultrasound, microwaves, and the
like. In some instances, the RF electrode is an electrical
conductor for delivering RF energy to a particular location, such
as a desired target tissue. For instance, in certain cases, the RF
electrode can be an RF ablation electrode. RF electrodes of the
subject tissue modification devices can include a conductor, such
as a metal wire, and can be dimensioned to access an intervertebral
disc space. RF electrodes may be shaped in a variety of different
formats, such as circular, square, rectangular, oval, etc. The
dimensions of such electrodes may vary, where in some embodiments
they RF electrode has a longest cross-sectional dimension that is 7
mm or less, 6 mm or less 5 mm or less, 4 mm or less, 3 mm or less
or event 2 mm or less, as desired. Where the electrode includes a
wire, the diameter of the wire in such embodiments may be 180
.mu.m, such as 150 .mu.m or less, such as 130 .mu.m or less, such
as 100 .mu.m or less, such as 80 .mu.m or less. A variety of
different RF electrode configurations suitable for use in tissue
modification and include, but are not limited to, those described
in U.S. Pat. Nos. 7,449,019; 7,137,981; 6,997,941; 6,837,887;
6,241,727; 6,112,123; 6,607,529; 5,334,183. RF electrode systems or
components thereof may be adapted for use in devices of the present
invention (when coupled with guidance provided by the present
specification) and, as such, the disclosures of the RF electrode
configurations in these patents are herein incorporated by
reference. Specific RF electrode configurations of interest are
further described in connection with the figures, below.
[0036] In some instances, the tissue modifier is supplied with
current from an RF energy source. The voltage signal driving the
current to the tissue modifier may be definable as a sine, square,
saw-tooth, triangle, pulse, non-standard, complex, or irregular
waveform, or the like, with a well-defined operating frequency. For
example, the operating frequency can range from 1 KHz to 50 MHz,
such as from 100 KHz to 25 MHz, and including from 250 KHz to 10
MHz. In some embodiments, the RF voltage signal is a sine wave with
operating frequency 460 kHz. Furthermore, the tissue modifier's
operating frequency can be modulated by a modulation waveform. By
"modulated" is meant attenuated in amplitude by a second waveform,
such as a periodic signal waveform. The modulation waveform may be
definable as a sine, square, saw-tooth, triangle, pulse,
non-standard, complex, or irregular waveform, or the like, with a
well-defined modulation frequency. For example, the modulation
frequency can range from 1 Hz to 10 kHz, such as from 1 Hz to 500
Hz, and including from 10 Hz to 100 Hz. In some embodiments, the
modulation waveform is a square wave with modulation frequency 70
Hz.
[0037] In some embodiments, a RF tuner is included as part of the
RF energy source. The RF tuner includes basic electrical elements
(e.g., capacitors and inductors) which serve to tailor the output
impedance of the RF energy source. The term "tailor" is intended
here to have a broad interpretation, including affecting an
electrical response that achieves maximum power delivery, affecting
an electrical response that achieves constant power (or voltage)
level under different loading conditions, affecting an electrical
response that achieves different power (or voltage) levels under
different loading conditions, etc. Furthermore, the elements of the
RF tuner can be chosen so that the output impedance is dynamically
tailored, meaning the RF tuner self-adjusts according to the load
impedance encountered at the electrode tip. For instance, the
elements may be selected so that the electrode has adequate voltage
to develop a plasma corona when the electrode is placed in a saline
solution (with saline solution grounded to return electrode), but
then may self-adjust the voltage level to a lower threshold when
the electrode contacts tissue (with tissue also grounded to return
electrode, for example through the saline solution), thus
dynamically maintaining the plasma corona at the electrode tip
while minimizing the power delivered to the tissue and the thermal
impact to surrounding tissue. RF tuners, when present, can provide
a number of advantages. For example, delivering RF energy to target
tissue through the distal tip of the electrode is challenging since
RF energy experiences attenuation and reflection along the length
of the conductive path from the RF energy source to the electrode
tip, which can result in insertion loss. Inclusion of a RF tuner,
e.g., as described above, can help to minimize and control
insertion loss.
[0038] Devices of the invention may include a linear mechanical
actuator for linearly translating a distal end element of the
device, such as the tissue modifier (e.g., a RF electrode) relative
to the distal end of the elongate member. By "linearly translating"
is meant moving the tissue modifier along a substantially straight
path. As used herein, the term "linear" also encompasses movement
of the tissue modifier in a non-straight (i.e., curved) path. For
instance, the path of movement of the tissue modifier can be
deflected from a substantially straight path if the electrode
encounters a tissue of a different density (such as, cartilage,
bone, etc.), or if the conformation of the tissue the electrode is
passing through is not straight, etc.
[0039] When actuated by a linear mechanical actuator, the tissue
modifier is cyclically displaced from a "neutral" position along
its axial extension to positions displaced distally or proximally
from the neutral position, with maximum displacement from the
neutral position corresponding to the vibratory amplitude. Thus,
the linear mechanical actuator actuates the tissue modifier through
a distance equal to twice the vibratory amplitude and ranging from
a distal extreme position to a proximal extreme position. In
certain embodiments, the tissue modifier can be extended by the
linear mechanical actuator from the distal end of the elongated
member by 0.1 mm or more, such as 0.5 mm or more, including 1 mm or
more, for instance 2 mm or more, such as 5 mm or more. This back
and forth movement of the tissue modifier relative to the distal
end of the elongated member that is implemented by the linear
mechanical actuator is described herein in terms of linear
translation frequency. It is noted that the above described distal
and proximal extreme positions refer to those positions implemented
solely by the linear mechanical actuator. In some embodiments, the
linear mechanical actuator may be the only means for translating
the electrode. In other embodiments, e.g., as described in greater
detail below, the linear mechanical actuator may provide vibratory
amplitude that is superimposed on another independent control over
electrode translation which moves the electrode over a distance
significantly greater than the vibratory amplitude, e.g. 10 mm or
more, such as 20 mm or more, including 30 mm or more, for instance
40 mm or more. In this case, the tissue modifier may be extended
beyond the range defined by the above described linear mechanical
actuator distal and proximal extreme positions. For example, a
manual control (e.g., a thumbwheel or analogous structure) may be
provided on the device which permits a user to move the tissue
modifier relative to the distal end in a movement that is distinct
from that provided by the linear mechanical actuator.
[0040] Accordingly, devices of the invention may include a linear
mechanical actuator configured to linearly translate the tissue
modifier relative to the distal end at linear translation
frequency. The linear mechanical actuator can be any of a variety
of actuators convenient for use in the subject devices for linearly
translating the tissue modifier relative to the distal end of the
elongated member. For instance, the linear mechanical actuator can
be a voice coil motor (VCM), solenoid, pneumatic actuator, electric
motor, etc. The linear mechanical actuator is operatively coupled
to the tissue modifier. By "operatively coupled" is meant that the
linear mechanical actuator is connected to the tissue modifier such
that linear movement by the actuator is transferred to the tissue
modifier thereby extending the tissue modifier from the distal end
of the elongated member or retracting the tissue modifier towards
the distal end of the elongated member depending on the direction
of movement by the linear actuator.
[0041] When present, the linear actuator provides for linear
translation of the tissue modifier at a linear translation
frequency. In some instances, the linear translation frequency is
10 Hz or greater, such as 25 Hz or greater, including 50 Hz or
greater, such as 100 Hz or greater. In some embodiments, the linear
translation frequency is 70 Hz. In certain cases, the translation
of the tissue modifier between the distal and proximal extreme
positions occurs with a predetermined linear translation frequency
while in other embodiments the linear translation frequency may not
be predetermined. The translation frequency (whether or not
predetermined) may depend on various factors, such as but not
limited to, the type of tissue being modified, the amount of tissue
being modified, the location of the tissue, the proximity of
surrounding tissues, the conformation of the tissue, the type of
procedure being performed, the nature of the linear mechanical
actuator, the DC voltage applied to the actuator, the amplitude of
the AC voltage applied to the actuator, etc. For example, in
certain embodiments, the linear translation frequency is definable
as a standard waveform, such as a sine waveform. In some cases, the
sine waveform is an Hz sine waveform, such that the linear
translation frequency ranges from 1 Hz to 500 Hz, such as from 1 Hz
to 250 Hz, and including from 10 Hz to 100 Hz. In other cases, the
linear translation frequency is definable as a non-standard,
complex, or irregular waveform, or the like. For example, the
linear translation frequency can be definable as a waveform
comprising periods that have varying frequencies, a waveform
comprising periods that have varying amplitudes, a waveform
comprising periods that have varying frequencies and varying
amplitudes, a superposition of two or more waveforms, and the
like.
[0042] In some embodiments, the tissue modification device is
configured to synchronize the linear mechanical actuation with the
modulated RF waveform. By "synchronize" is meant that two or more
events are timed to operate in a coordinated manner. For example,
two or more waveforms can be timed to operate in a coordinated
manner. In some embodiments, the modulation frequency equals the
linear translation frequency, and the modulation waveform is
phase-shifted relative to the linear translation waveform.
Synchronization of these waveforms may be achieved using a variety
of different protocols and may implement one or more controllers of
different formats, including hardware, software, and combinations
thereof. For instance, a single common controller may generate two
waveforms that are phase-shifted; alternatively, separate
controllers can be arranged in a master-slave configuration to
generate two waveforms that are phase-shifted; alternatively, one
controller can generate a waveform, hardware (e.g., an
opto-electronic encoder, a mechanical encoder, a hall sensor, or
the like) can be used to trigger on a physical embodiment (such as
mechanical rotation) of that waveform, and a second controller can
generate a second waveform with adjustable phase shift from the
trigger signal. The phase shift of the modulation waveform relative
to the linear translation waveform can be positive (phase lead) or
negative (phase lag), and can have magnitude 0.degree. to
360.degree. or more, such as 0.degree. to 180.degree., including
60.degree. to 120.degree.. In certain embodiments of the invention,
the modulation waveform lags the linear translation waveform by
90.degree..
[0043] As discussed above, the tissue modifier (e.g., a RF
electrode) has distal and proximal extreme positions of its cyclic
linear translation. In certain embodiments, the tissue modifier is
configured to deliver RF energy to an internal target tissue while
at a position other than the distal extreme position. Thus, in
these cases, the modulation waveform is synchronized with the
linear translation waveform such that the tissue modifier is
energized when the tissue modifier is at a position other than the
distal extreme position, such as while the tissue modifier is at or
near the proximal extreme position. For example, as discussed
above, the modulating waveform may be phase-shifted relative to the
linear translation waveform.
[0044] Cyclic linear translation of the tissue modification device
can facilitate a variety of functions with multiple benefits. For
instance, cyclic linear translation of the tissue modifier at a
fast rate relative to manually controlled translation (e.g., at a
frequency greater than 10 Hz) will tend to physically advance the
tissue modifier into soft tissue due to the compliance of the soft
tissue, while hard tissue will resist deformation and will thus not
allow the tissue modifier to physically advance into the hard
tissue. Consequently, the electrode will push back against the
elongated body as it encounters hard tissue, thus producing tactile
feedback to the user. In some embodiments, synchronization of the
tissue modifier's modulation waveform with its linear translation
waveform provides additional benefits. For instance, rapid
retraction of the electrode from hard tissue that it encounters
will leave the tissue modifier physically separated from the hard
tissue by a gap as the tissue modifier approaches the proximal
extreme position. In some embodiments, the tissue modifier tip is
activated only when the tissue modifier is at or near the proximal
extreme position, as mentioned above. This has the effect of
preferentially delivering the tissue modification energy to soft,
compliant tissue as opposed to hard, stiff tissue. Stated
otherwise, this provides tissue discrimination based on elastic
modulus. In the case of spinal surgery applications requiring
removal of nuclear material, such as fusion, total disc
replacement, and partial disc replacement, synchronization of the
modulation waveform with the linear translation waveform
facilitates the delivery of tissue modification energy to the
nucleus pulposus (soft, compliant tissue) while minimizing the
delivery of tissue modification energy to the disc annulus (hard,
stiff tissue) and the endplates of the vertebral bodies (hard,
stiff tissue). In addition, cyclic linear translation of the tissue
modifier helps to prevent a condition where the electrode sticks to
tissue as it ablates it, resulting in increased thermal effects to
the surrounding tissue, ineffective or discontinuous tissue
dissection, buildup of charred or otherwise modified tissue on the
tissue modifier tip, or a combination thereof. Additionally, cyclic
linear translation of the tissue modifier helps chop the dissected
tissue into smaller pieces, thus facilitating aspiration of the
dissected tissue.
[0045] Depending on the nature of the tissue modifier, the devices
will include proximal end connectors for operatively connecting the
device and tissue modifier to extra-corporeal elements required for
operability of the tissue modifier, such as extra-corporeal RF
controllers, mechanical tissue cutter controllers, liquid jet
controllers, etc.
[0046] In some embodiments, an integrated articulation mechanism
that imparts steerability to at least one of the visualization
sensor, the tissue modifier and the distal end of the elongated
member is also present in the device. By "steerability" is meant
the ability to maneuver or orient the visualization sensor, tissue
modifier and/or distal end of the elongated member as desired
during a procedure, e.g., by using controls positioned at the
proximal end of the device. In these embodiments, the devices
include a steerability mechanism (or one or more elements located
at the distal end of the elongated member) which renders the
desired distal end component maneuverable as desired through
proximal end control. As such, the term "steerability", as used
herein, refers to a mechanism that provides a user steering
functionality, such as the ability to change direction in a desired
manner, such as by moving left, right, up or down relative to the
initial direction. The steering functionality can be provided by a
variety of different mechanisms. Examples of suitable mechanisms
include, but are not limited to one or more wires, tubes, plates,
meshes or combinations thereof, made from appropriate materials,
such as shape memory materials, music wire, etc. In some instances,
the distal end of the elongated member is provided with a distinct,
additional capability that allows it to be independently rotated
about its longitudinal axis when a significant portion of the
operating handle is maintained in a fixed position, as discussed in
greater detail below. The extent of distal component articulations
of the invention may vary, such as from -180 to +180.degree.; e.g.,
-90 to +90.degree.. Alternatively, the distal probe tip
articulations may range from 0 to 360.degree., such as 0 to
+180.degree., and including 0 to +90.degree., with provisions for
rotating the entire probe about its axis so that the full range of
angles is accessible on either side of the axis of the probe, e.g.,
as described in greater detail below. Articulation mechanisms of
interest are further described in published PCT Application
Publication Nos. WO 2009029639; WO 2008/094444; WO 2008/094439 and
WO 2008/094436; the disclosures of which are herein incorporated by
reference. Specific articulation configurations of interest are
further described in connection with the figures, below.
[0047] In certain embodiments, devices of the invention may further
include an irrigator and aspirator configured to flush an internal
target tissue site and/or a component of the device, such as a lens
of the visualization sensor. As such, the elongated member may
further include one or more lumens that run at least the
substantial length of the device, e.g., for performing a variety of
different functions, as summarized above. In certain embodiments
where it is desired to flush (i.e., wash) the target tissue site at
the distal end of the elongated member (e.g. to remove ablated
tissue from the location, etc.), the elongated member may include
both irrigation lumens and aspiration lumens. Thus, the tissue
modification device can comprise an irrigation lumen located at the
distal end of the elongated member, and the tissue modification
device can include an aspiration lumen located at the distal end of
the elongated member. During use, the irrigation lumen is
operatively connected to a fluid source (e.g., a physiologically
acceptable fluid, such as saline) at the proximal end of the
device, where the fluid source is configured to introduce fluid
into the lumen under positive pressure, e.g., at a pressure ranging
from 0 psi to 60 psi, so that fluid is conveyed along the
irrigation lumen and out the distal end. While the dimensions of
the irrigation lumen may vary, in certain embodiments the longest
cross-sectional dimension of the irrigation lumen ranges from 0.5
mm to 5 mm, such as 0.5 mm to 3 mm, including 0.5 mm to 1.5 mm.
During use, the aspiration lumen is operatively connected to a
source of negative pressure (e.g., a vacuum source) at the proximal
end of the device. While the dimensions of the aspiration lumen may
vary, in certain embodiments the longest cross-sectional dimension
of the aspiration lumen ranges from 1 mm to 7 mm, such as 1 mm to 6
mm, including 1 mm to 5 mm. In some embodiments, the aspirator
comprises a port having a cross-sectional area that is 33% or more,
such as 50% or more, including 66% or more, of the cross-sectional
area of the distal end of the elongated member. In some instances,
the negative pressure source is configured to draw fluid and/or
tissue from the target tissue site at the distal end into the
aspiration lumen under negative pressure, e.g., at a negative
pressure ranging from 300 to 600 mmHg, such as 550 mmHg, so that
fluid and/or tissue is removed from the tissue site and conveyed
along the aspiration lumen and out the proximal end, e.g., into a
waste reservoir. In certain embodiments, the irrigation lumen and
aspiration lumen may be separate lumens, while in other
embodiments, the irrigation lumen and the aspiration lumen can be
included in a single lumen, for example as concentric tubes with
the inner tube providing for aspiration and the outer tube
providing for irrigation. When present, the lumen or lumens of the
flushing functionality of the device may be operatively coupled to
extra-corporeal irrigation devices, such as a source of fluid,
positive and negative pressure, etc. Where desired, irrigators
and/or aspirators may be steerable, as described above.
[0048] Where desired, the devices may include a control structure,
such as a handle, operably connected to the proximal end of the
elongated member. By "operably connected" is meant that one
structure is in communication (for example, mechanical, electrical,
optical connection, or the like) with another structure. When
present, the control structure (e.g., handle) is located at the
proximal end of the device. The handle may have any convenient
configuration, such as a hand-held wand with one or more control
buttons, as a hand-held gun with a trigger, etc., where examples of
suitable handle configurations are further provided below.
[0049] In some embodiments, the distal end of the elongated member
is rotatable about its longitudinal axis when a significant portion
of the operating handle is maintained in a fixed position. As such,
at least the distal end of the elongated member can turn by some
degree while the handle attached to the proximal end of the
elongated member stays in a fixed position. The degree of rotation
in a given device may vary, and may range from 0 to 360.degree.,
such as 0 to 270.degree., including 0 to 180.degree..
[0050] Devices of the invention may be disposable or reusable. As
such, devices of the invention may be entirely reusable (e.g., be
multi-use devices) or be entirely disposable (e.g., where all
components of the device are single-use). In some instances, the
device can be entirely reposable (e.g., where all components can be
reused a limited number of times). Each of the components of the
device may individually be single-use, of limited reusability, or
indefinitely reusable, resulting in an overall device or system
comprised of components having differing usability parameters.
[0051] Devices of the invention may be fabricated using any
convenient materials or combination thereof, including but not
limited to: metallic materials such as tungsten, stainless steel
alloys, platinum or its alloys, titanium or its alloys, molybdenum
or its alloys, and nickel or its alloys, etc; polymeric materials,
such as polytetrafluoroethylene, polyimide, PEEK, and the like;
ceramics, such as alumina (e.g., STEATITE.TM. alumina, MAECOR.TM.
alumina), etc.
[0052] Various aspects of device embodiments of the invention have
been described in varying detail above. Device embodiments will now
be described in further detail in terms of figures. FIGS. 1A and 1B
provide two different side views of a device 100 according to one
embodiment of the invention. Device 100 includes an elongated
member 110 and an operating handle 120 at the proximal end of the
elongated member 110. The operating handle has a gun configuration
and includes a trigger 125 and thumbwheel 130 which provide a user
with manual operation over certain functions of the device, e.g.,
RF electrode positioning and extension. Located at the distal end
of the elongated member is an integrated visualization sensor 140
and tissue modifier 150. Control elements 160 (which may include
aspiration and irrigation lumens, control/power wires, etc.) exit
the handle 120 at the distal end region 170, which region 170 is
rotatable relative to the remainder of the handle 120. A variety of
additional components may be present at the distal end of the
elongated member, which additional elements may include irrigators,
aspirators, articulation mechanisms, etc. as described generally
above. More details regarding the distal end of elongate member 140
may be seen in FIG. 6D.
[0053] FIGS. 2A to 2C provide cross-sectional views of the distal
ends of elongated members according to three different embodiments
of the device. Each of these views shows how the visualization
sensor and tissue modifier may be integrated at the distal end
despite the limited size of the distal end.
[0054] FIG. 2A shows an example cross-section of the distal end 200
of an elongated member of a device according one embodiment of the
invention. Distal end 200 includes an integrated CMOS visualization
sensor 210, which has a 2.5 mm diameter. Also shown are guide-wires
215 which have a 1 mm diameter and provide for articulation of the
distal end of the device. Integrated mechanical cutter 230 has a
1.58 mm diameter. Light source 240 has a 1.33 mm diameter. Also
shown is lumen 250 which provides for aspiration and irrigation.
FIG. 2A is drawn to scale, demonstrating that integrated
visualization, tissue modification, illumination and irrigation can
be positioned at the distal end of an elongated member that has a
5.00 mm outer diameter.
[0055] FIG. 2B shows the cross-section of a distal end of elongated
member that is analogous to that shown in FIG. 2A, with the
exception that smaller diameter guidewires (0.80 mm) are employed.
As a result, light source 240 may have a 1.50 mm diameter and
mechanical cutter 230 may have a 1.92 mm diameter. Like the
embodiment shown in FIG. 2A, FIG. 2B is drawn to scale,
demonstrating that integrated visualization, tissue modification,
illumination and irrigation can be positioned at the distal end of
an elongated member that has a 5.00 mm outer diameter.
[0056] FIG. 2C shows the cross-section of a distal end of elongated
member that is analogous to that shown in FIG. 2A, with the
exception that smaller non-circular cross-section guidewires (1.20
mm.times.0.60 mm) are present. As a result, light source 240 may
have a 1.63 mm diameter and mechanical cutter 230 may have a 2.22
mm diameter. Like the embodiment shown in FIG. 2A, FIG. 2C is drawn
to scale, demonstrating that integrated visualization, tissue
modification, illumination and irrigation can be positioned at the
distal end of an elongated member that has a 5.00 mm outer
diameter.
[0057] FIG. 3A shows an example cross-section a distal end of a
device according to an embodiment of the invention. FIG. 3A
illustrates the distal end of a device 300 having a distal end
outer diameter of 6.6 mm, where the drawing is to scale. The distal
end of device 300 includes an integrated camera 320 (e.g., a CMOS
sensor) having an outer diameter of 2.8 mm and two fiber optic
light sources 330 each having an outer diameter of 1.3 mm. Also
integrated at the distal end are electrode cutters 340 (having
dimensions of 2.0 mm.times.0.7 mm) each associated with an
irrigation lumen 350 (having dimensions of 1.2 mm.times.0.8 mm). In
addition, the distal end includes central aspiration lumen 360
which has a rectangular configuration and dimensions of 5.0
mm.times.1.8 mm. In FIG. 3A, the integrated camera 320 is
overlapping with other elements, which illustrates how the camera
cross-section only occupies space at the most distal portion of the
device 300. Overlapping portions of cross sections of other
components, including the aspiration lumen 360, would be terminated
or diverted laterally before reaching the proximal end of the
camera. During use of the device for removal of tissue from a
target tissue location, the following steps may be performed. First
the distal end 300 of the device is introduced into the target
tissue dissection region through access device 310. Access device
310 may be any convenient device, such as a conventional retractor
tube. Access device 310 as shown in FIG. 3A has an inner diameter
of 7.0 mm and an outer diameter of 9.5 mm. At this stage,
orientation of camera 320 is biased to one side (left side in
figure). During insertion, the electrode 340 on the side opposite
the viewing field of the camera (right side in figure) is distally
translated so that it emerges distally from the distal tip of the
device 300. Also during insertion, the distally translated
electrode 340 is activated by supplying RF current and irrigating
conducting fluid, resulting in tissue dissection during insertion
of the device. For further tissue dissection on the side to which
the camera is biased (left side in figure), the electrode 340 on
the same side as the viewing field of the camera (left side in
figure) is distally translated so that it emerges laterally from
the endoscope probe on the proximal side of the camera. While being
translated, the same electrode (left side in figure) is activated
by supplying RF current and irrigating conducting fluid, resulting
in tissue dissection. At this point, the entire end of the device
300 may be translated proximally and distally until the desired
tissue dissection is obtained. When finished with tissue dissection
at the first location, the device may be rotated 180 degrees and
further tissue removed using the steps described above.
[0058] FIG. 3B shows an example cross-section of the distal end of
a device 300 similar to that in FIG. 3A, except that it includes
additional irrigation lumens 370 (outer diameter 1.2 mm) in
addition to the irrigation lumens 350 (dimensions of 1.5
mm.times.0.9 mm) associated with the electrodes 340 (dimensions 2.5
mm.times.1.1 mm). Also, the geometry of the aspiration tube is
hexagonal rather than rectangular to maximize use of space for this
geometry (dimensions 4.2 mm.times.2.3 mm). The drawing is to scale,
and shows another example of what can be integrated at the distal
end of a device having a 6.6 mm outer. As shown, the cross section
of the camera 320 is overlapping with other elements as in FIG. 3A,
which shows how the camera cross-section only occupies space at the
most distal portion of the device. Overlapping portions of other
cross sections, including the light sources, one of the electrodes,
and the aspiration tube, would be terminated or diverted laterally
before reaching the proximal end of the camera. Operating this
device may include the same steps as described above in connection
with the device of FIG. 3A, except that additional irrigation could
be used to help flush out dissected tissue and to clean the camera
lens using the additional irrigation lumens 370.
[0059] FIG. 3C shows an example cross-section of the distal end 300
of a device similar to that in FIG. 3B, except that the orientation
one of the electrodes 340 is reversed and the geometry of the
aspiration tube 360 is trapezoidal rather than hexagonal to
maximize use of space for this geometry. The drawing is to scale,
and shows another example of components that can be integrated into
a 6.6 mm outer diameter device distal end. In FIG. 3C, the
dimensions of the components are the same as that of FIG. 3B, with
the exception that irrigation lumens 370 have an outer diameter of
1.1 mm, the dimensions of aspiration lumen 360 are 4.2 mm.times.2.7
mm, the dimensions of electrodes 340 are 2.5 mm.times.1.1 mm and
the dimensions of electrode irrigation lumens 350 are 1.5
mm.times.0.9 mm. As in the devices shown in FIGS. 3A and 3B, the
camera cross section is overlapping with other elements, which
shows how the camera cross-section 320 only occupies space at the
most distal portion of the probe. Overlapping portions of other
cross sections, including the light sources, one of the electrodes,
and the aspiration tube, would be terminated or diverted laterally
before reaching the proximal end of the camera 320. Operating this
device may include the same steps as described above in connection
with the device of FIGS. 3A and 3B.
[0060] FIG. 3D shows an example cross-section of the distal end 300
of a device that is similar to that in FIG. 3C, except that only
one electrode 340 (dimensions 5.4 mm diameter.times.0.35 mm thick)
is used and it is much larger than the electrode present in the
device shown in FIG. 3C. The electrode irrigation lumen is also
dimensioned differently, having dimensions of 1.5 mm.times.0.6 mm.
In FIG. 3C, integrated camera 320 is shown with camera cables 380
(having dimensions of (1.5 mm.times.0.8 mm). Also, the geometry of
the aspiration lumen is a semi-circular rather than trapezoidal to
maximize use of space for this geometry, where the dimensions of
the aspiration lumen are 3.4 mm.times.2.1 mm. The drawing is to
scale, and shows an example of the components that can be
integrated at the distal end of a device that has a 6.6 mm outer
diameter. The device is shown present in an access tube having a
7.2 mm inner diameter and a 9.5 mm outer diameter. In FIG. 3D, the
camera 320 cross section is overlapping with other elements as in
FIGS. 3A to 3C, demonstrating that the camera 320 cross-section
only occupies space at the most distal portion of the probe.
Overlapping portions of other cross sections, including the light
sources and the aspiration tube, would be terminated or diverted
laterally before reaching the proximal end of the camera. Operating
this device may include the same steps as described above in
connection with the device of FIGS. 3A to 3C, except that the
single electrode serves the function of both electrodes in FIGS. 3A
to 3C. The electrode is distally translated only a short distance
for distal cutting, and then it is distally translated farther to
cause it to extend laterally to the side viewed by the camera for
tissue dissection on that side.
[0061] FIG. 3E shows an example cross-section of the distal probe
tip similar to that in FIG. 3D, except that one of the irrigation
channels is replaced by a probe tool 390, having an outer diameter
of 1.2 mm, which is employed to manipulate tissue and expose target
tissue regions for visualization and/or modification by a tissue
modifier, such as the electrode device 340. The drawing is to
scale, and shows another example of components that can be
integrated at the distal end of a device having a 6.6 mm outer
diameter. Operating this device may include the same steps as
described above in connection with the device of FIGS. 3A to 3D,
except that the probe is also available for probing the tissue
dissection region and for assisting in desired tissue
dissection.
[0062] FIG. 4 provides a side view of a device according to an
embodiment of the invention, where the device includes a
side-viewing integrated camera at its distal end. In FIG. 4, device
400 includes integrated camera 410 having a side-viewing or biased
lens 420, which provides a field of view which includes components
from both the forward and side views of the device. As shown, the
side-viewing camera is angled at a degree ranging from 15 to
65.degree. relative to the longitudinal axis of the elongated
member. Device 400 also includes an integrated tissue cutter 430
(e.g., in the form of an RF electrode) and integrated light source
435. Device 400 is shown in relation to intervertebral disc 440,
where the distal end of the device 400 extends through the annulus
fibrosis 450 into the nucleus pulposus 460.
[0063] FIG. 5 provides a side view of a device 500 according to an
embodiment of the invention, where the device includes a
side-viewing integrated camera 510 at its distal end and two
steerable electrodes 520 and 525. In FIG. 4, device 500 includes
integrated camera 510 having a side-viewing or biased lens 520.
Device 500 also includes an integrated electrodes 530 and 535 which
are steerable (e.g., being fabricated from a shape-memory material)
and integrated light source 540. Device 500 is shown in relation to
intervertebral disc 540, where the distal end of the device 500
extends through the annulus fibrosis 450 into the nucleus pulposus
460.
[0064] FIGS. 6A and 6B are isometric views of an embodiment of the
distal end of a tissue modification device illustrating the
invention inserted into the intervertebral disc space. The tissue
modification device 600 includes an elongated member 610 inserted
through the disc annulus 620 into the nucleus pulposus 630 of the
intervertebral disc space. The tissue modification device 600 also
includes an RF electrode 640 extended from the distal end of
guidetubes 650, which are extended from the distal end of the
elongated member 610. The guidetubes 650 are extended from the
distal end of the elongated member 610 and have a curved shape,
which facilitates access of the RF electrode 640 to the entire
intervertebral disc space. The tissue modification device 600 also
includes an integrated CMOS visualization element 660 at the distal
end of the elongated member 610.
[0065] FIGS. 6A and 6B provide views of an RF electrode that is
steerable at its distal end. In the embodiment depicted in FIGS. 6A
and 6B, the steering functionality of the RF electrode is provided
by a shape-memory element in conjunction with a guidetube. The term
"shape-memory" as used herein refers to a material that can return
to its original shape after being deformed. In certain embodiments,
the shape-memory element comprises a shape-memory alloy, such as,
but not limited to, a nickel-titanium (e.g., NITINOL) alloy, a
copper-zinc-aluminum-nickel alloy, a copper-aluminum-nickel alloy,
or the like. For example, the steering functionality of the RF
electrode can be provided by wires comprising a shape-memory alloy.
The shape-memory wires can be attached to the RF electrode such
that when the RF electrode is extended from the distal end of the
elongated member, the shape-memory wires take on a predetermined
conformation, thus moving the RF electrode into substantially the
same conformation. In certain cases, the shape-memory element is
provided in conjunction with a guidetube. The guidetube can be a
tube (i.e., a cylinder with a hollow central lumen) provided within
the elongated member for housing the RF electrode and for guiding
the direction of the RF electrode. Thus, the RF electrode can be
provided within the central lumen of the guidetube. The guidetube
can be composed of any convenient biocompatible material, such as
plastic, rubber, metal, and the like. The guidetube can be provided
with one or more shape-memory elements, such as wires comprising a
shape-memory alloy, as described above. In certain embodiments, the
guidetube is a shape-memory guidetube, such as a guidetube
comprising a shape-memory alloy.
[0066] In some cases, the guidetube is slidably positioned in the
elongated member, and may be extended from the distal end of the
elongated member. In some cases, the shape-memory guidetube has a
curved shape when extended from the distal end of the elongated
member, such that the guidetube extends at an angle from the
longitudinal axis of the elongated member. For example, when the
guidetube is fully extended from the distal end of the elongated
member, the guidetube may form an arc shape where the guidetube
comprises an arc of 1.degree. to 360.degree., such as 30.degree. to
180.degree., including 60.degree. to 120.degree.. As described
above, the guidetube can be provided with an RF electrode in the
central lumen of the guidetube. In some instances, the guidetube is
configured to facilitate the RF electrode's access to the entire
intervertebral disc space. In certain instances, accessibility to
the entire IVD space is facilitated by articulation of one or more
of the RF electrode, the guidetube, and the elongated member. In
addition, the RF electrode can be slidably positioned in the
guidetube, and may be extended from the distal end of the
guidetube. The elongated member, the RF electrode and/or the
guidetube can be independently rotated, providing additional
accessibility within the IVD space.
[0067] In certain embodiments, the tissue modification device
includes two or more guidetubes, where the guidetubes are slideably
translateable with respect to the elongated member. In some cases,
the guidetubes are slideably translateable with respect to each
other, which facilitates extending the RF electrode at an angle
from the longitudinal axis of the elongated member or deforming the
electrode tip into a new shape or configuration. Thus, one
guidetube can be extended or retracted with respect to the distal
end of the elongated member independent of the other guidetube(s).
For instance, the movement of each guidetube can be controlled by
the user, such that the user can extend, retract or steer each
guidetube individually.
[0068] In some cases, the RF electrode comprises a wire slidably
positioned in a shape-memory guidetube that is slidably positioned
in the elongated member. In certain instances, the RF electrode
comprises an exposed portion positioned between first and second
ends, where the first and second ends are each positioned in a
shape-memory guidetube. By "exposed" is meant that a portion of the
RF electrode is able to make electrical contact with the desired
target tissue. In these cases, the first and second ends are
linearly translatable, where the first and second ends are
translatable in unison, such that the first and second ends can be
extended and retracted from the distal end of the elongated member
at the same rate. In other instances, the first and second ends are
linearly translatable with respect to each other, such that the
first and second ends can be extended and retracted from the distal
end of the elongated member at different rates or to different
positions of extension from the distal end of the elongated member.
This facilitates the movement of the exposed portion of the RF
electrode at an angle from the longitudinal axis of the elongated
member. For example, when the RF electrode is extended from the
distal end of the elongated member, the angle between the RF
electrode and the longitudinal axis of the elongated member can be
from 1.degree. to 270.degree., such as 30.degree. to 180.degree.,
including 60.degree. to 120.degree..
[0069] As shown in FIGS. 6A and 6B, the RF electrode 640 is a
U-shaped structure that includes a distal cutting end (the exposed
region), bounded on each side by a ceramic member. This U-shaped
configuration is further illustrated in FIG. 6E. The ceramic
members 617 flanking each side of the distal cutting end 619 may be
joined (e.g., such that they have a cross-bar configuration as
shown in FIGS. 6A and 6B) or be separate component from each other
(e.g., as shown in FIG. 6E). These components may be fabricated
from any convenient ceramic material, including but not limited to
alumina, such as STEATITE.TM. alumina, MAECOR.TM. alumina, and the
like. In FIG. 6E, the extended length of region 619 may vary,
ranging from 2 to 20 mm, such as 2 to 10 mm and including 2 to 6
mm. The diameter of the wire making up region 619 may vary, and in
certain embodiments is 180 .mu.m, such as 150 .mu.m or less, such
as 130 .mu.m or less, such as 100 .mu.m or less, such as 80 .mu.m
or less. While the distal cutting end or region 619 may be
fabricated from a variety of materials, in some instances this
portion of the electrode is fabricated from a material that is
different from the material of the electrode wires 621. Materials
of interest from which the distal cutting end 619 may be fabricated
include, but are not limited to tungsten, tungsten alloys, e.g.,
tungsten rhenium, steel, tungsten coated with noble metals, such as
Pt, Au, etc., and the like.
[0070] FIG. 6C provides a view of the distal end of device that is
analogous to that shown in FIGS. 6A and 6B. FIG. 6C shows how a
variety of components including an integrated CMOS visualization
sensor 660, irrigation lumens 665, aspiration lumen 670, and
steerable RF electrode 640 can be incorporated into the distal end
of an elongated member having an outer diameter that is 7.0 mm or
less, such as 6.5 mm or less. Electrode 640 is made up of electrode
wires extending from electrode guidetubes 650. Separating the
electrode wires from the distal cutting end 690 are ceramic
electrode crimp elements 680. Electrode wires 640 and guidetubes
650 are shown in an extended configuration in FIG. 6C but each
independently may be fabricated from a shape memory material so as
to assume a curved configuration (as shown in FIGS. 6A and 6B) and
therefore impart steerability to the RF electrode. As shown in FIG.
6C, aspiration lumen 670 opens to the side of the device 600 and is
positioned just proximal of the CMOS visualization sensor 660 so
that all of the disparate components may be integrated at the
distal end of the device.
[0071] FIG. 6D provides a three-dimensional view of one embodiment
of a distal end of tissue modification device 600 (having a 6.5 mm
outer dimension) of the invention. In FIG. 6D, the distal end of
the device includes and integrated circular CMOS visualization
sensor 605 and integrated LED 610. Also shown is a first forward
facing irrigation lumen 615 and a second irrigation lumen 617 which
is slightly extended from the distal end and is side facing so that
fluid emitted from lumen 617 is flowed across CMOS visualization
sensor 605 to clean the sensor of debris, when needed. Also shown
is an aspiration lumen 625 positioned proximal the irrigation
lumens 615 and 617 and integrated CMOS visualization sensor 605,
where the aspiration lumen 605 is configured to aspirate fluid and
tissue debris from a target tissue site during use. The distal end
further includes an integrated steerable RF electrode assembly 655.
RF electrode assembly 655 includes NITINOL shape memory guide tubes
645 extending from insulated (e.g., RF shielded) guide lumens 642.
The RF electrode further includes a tungsten cutting wire 665
joined at each end to a NITINOL shape memory electrode wire 663 by
a ceramic arc stop 675. As shown, the diameter of the cutting wire
665 is smaller than the diameter of the electrode wires 663, where
the difference in size may vary and may range from 100 to 500
.mu.m, such as 300 to 400 .mu.m.
[0072] FIGS. 1A and 1B, reviewed above, provide different views of
a device according to an embodiment of the invention, where the
device includes a distal end as shown in FIG. 6D. FIG. 7 provides a
cutaway view of the devices shown in FIGS. 1A and 1B. As shown in
FIG. 7, the device includes trigger element 125 which translates
the guidetubes relative to the distal end of the elongated member.
Also shown is thumbwheel 130 which provides for manual movement of
the electrode relative to the distal end. The cutaway view of FIG.
7 shows mechanical actuator 180 which provides for linear
translation of electrode 190 positioned at the distal end of the
elongated member.
[0073] Tissue modification devices of the invention are configured
to be hand-held. Accordingly, in certain instances the tissue
modification devices have a mass that is 1.5 kg or less, such as 1
kg or less, including 0.5 kg or less, e.g., 0.25 kg or less.
Systems
[0074] Aspects of the subject invention include tissue modification
systems, where the systems include a tissue modification device,
e.g., as described above, operatively connected to one or more
extra-corporeal control units (i.e., extra-corporeal controllers).
Extra-corporeal control units may include a number of different
components, such as power sources, irrigation sources, aspiration
sources, image data processing components, image display components
(such as monitors, printers, and the like), data processors, e.g.,
in the form of computers, data storage devices, e.g., floppy disks,
hard drives, CD-ROM, DVD, flash memory, etc., device and system
controls, etc.
[0075] An example of a system according to an embodiment of the
invention is shown in FIG. 8. In FIG. 8 the system includes
hand-held tissue modification device 800 and extra-corporeal
control unit 850. Hand-held device 800 includes distal end 810 and
handle 820 configured to be held in the hand of an operator.
Positioned at the distal end 810 are the integrated visualization
and tissue modification components (as well as other components),
as shown by cross-section 830. Extra-corporeal control unit 850
includes image display 860 (e.g., a liquid crystal display
monitor), video digital signal processor 870, energy source 880
(e.g., configured to operate an RF tissue modification member) and
irrigation/aspiration system 890. The hand-held device 800 and
extra-corporeal control unit 850 are operatively connected to each
other by a cable.
[0076] FIG. 9 provides a diagrammatic view of the architecture of a
system according to one embodiment of the invention and how the
various components of the system may interact with a user, such as
a surgeon, during use. In FIG. 9, extra-corporeal control unit 910
includes a video processing unit 911, an RF electrode power source
912, an irrigation source 913 and an aspiration source 914. Each of
these components is operatively connected to electrical controls
915, with which the user 990 may interact to operate the system as
desired. Also shown is tissue modification device 950 which
includes an integrated visualization sensor 951, an RF electrode
952, an irrigation lumen 953, an aspiration lumen 954 and an
articulation mechanism 955. The tissue modification device 950
provides a number of functionalities 960, including tissue
dissection 961, tissue removal 962, tissue discrimination 963 and
accessibility 964. The system provides numerous user interface
opportunities 930; including image display 931, tactile feedback
932 and mechanical controls 933.
[0077] Within a given system, the integrated distal end
visualization sub-system may have a variety of different
configurations. FIG. 10 provides an example of an embodiment of an
integrated visualization sub-system that includes a distal end CMOS
visualization sensor. As shown in FIG. 10, visualization sub-system
1000 includes distal end CMOS visualization sensor 1010 that
includes lens housing 1015 component operatively coupled to
integrated circuit component 1020. As shown in the figure, lens
housing 1015 includes a lens set 1016. Also shown at the distal end
is LED 1018 which provides illumination for a target tissue
location during use. Integrated circuit component 1020 includes
CMOS sensor integrated circuit 1021 and rigid printed circuit board
1022. The sub-components of lens housing/light source component
1015 are operatively coupled to flexible cable 1030 which provides
for operative connection of the CMOS visualization system at the
distal end of the device via the handle 1040 to the video
processing sub-system 1050. In the handle 1040 the flexible cable
operatively connects to a shielded cable 1052 which provides for RF
isolation. As shown in FIG. 10, the various components are shielded
from RF, e.g., by coating the elements with a conductive material
which is then connected to a ground. For example, lens housing 1015
and cable 1030 are RF shielded. RF shielded cable 1052 connects to
video processing sub-system 1050 which includes a variety of
functional blocks, such as host controller 1051 (coupled to PC
1061), digital signal processor 1052 (coupled to LCD 1062) and CMOS
visualization sensor bridge 1053. As shown in FIG. 10, video
processing sub-system 1050 is ground to earth 1072 by connection to
metal case 1070.
[0078] Systems of the invention may include a number of additional
components in addition to the tissue modification devices and
extra-corporeal control units, as described above. Additional
components may include access port devices; root retractors;
retractor devices, system component fixation devices; and the like;
etc. Of interest are systems that further access devices as
described in co-pending U.S. application Ser. Nos. 12/269,770;
12/269,772; and 12/269,775; the disclosures of which are herein
incorporated by reference.
Methods
[0079] Aspects of the subject invention also include methods of
imaging and/or modifying an internal target tissue of a subject.
Accordingly, aspects of the invention further include methods of
imaging an internal tissue site with tissue modification devices of
the invention. A variety of internal tissue sites can be imaged
with devices of the invention. In certain embodiments, the methods
are methods of imaging an intervertebral disc in a minimally
invasive manner. For ease of description, the methods are now
primarily described further in terms of imaging IVD target tissue
sites. However, the invention is not so limited, as the devices may
be used to image a variety of distinct target tissue sites.
[0080] With respect to imaging an intervertebral disc or portion
thereof, e.g., exterior of the disc, nucleus pulposus, etc.,
embodiments of such methods include positioning a distal end of a
minimally invasive intervertebral disc imaging device of the
invention in viewing relationship to an intervertebral disc or
portion of there, e.g., nucleus pulposus, internal site of nucleus
pulposus, etc. By viewing relationship is meant that the distal end
is positioned within 40 mm, such as within 10 mm, including within
5 mm of the target tissue site of interest. Positioning the distal
end in viewing device in relation to the desired target tissue may
be accomplished using any convenient approach, including through
use of an access device, such as a cannula or retractor tube, which
may or may not be fitted with a trocar, as desired. Following
positioning of the distal end of the imaging device in viewing
relationship to the target tissue, the target tissue, e.g.,
intervertebral disc or portion thereof, is imaged through use of
the illumination and visualization elements to obtain image data.
Image data obtained according to the methods of the invention is
output to a user in the form of an image, e.g., using a monitor or
other convenient medium as a display means. In certain embodiments,
the image is a still image, while in other embodiments the image
may be a video.
[0081] In certain embodiments, the methods include a step of tissue
modification in addition to the tissue viewing. For example, the
methods may include a step of tissue removal, e.g., using a
combination of tissue cutting and irrigation or flushing. For
example, the methods may include cuffing a least a portion of the
tissue and then removing the cut tissue from the site, e.g., by
flushing at least a portion of the imaged tissue location using a
fluid introduced by an irrigation lumen and removed by an
aspiration lumen.
[0082] The internal target tissue site may vary widely. Internal
target tissue sites of interest include, but are not limited to,
cardiac locations, vascular locations, orthopedic joints, central
nervous system locations, etc. In certain cases, the internal
target tissue site comprises spinal tissue.
[0083] The subject methods are suitable for use with a variety of
mammals. Mammals of interest include, but are not limited to: race
animals, e.g. horses, dogs, etc., work animals, e.g. horses, oxen
etc., and humans. In some embodiments, the mammals on which the
subject methods are practiced are humans.
[0084] An example of a method which employs the device depicted in
FIG. 3A includes the following steps. First the distal end 300 of
the device is introduced into the target tissue dissection region
through access device 310. Access device 310 may be any convenient
device, such as a conventional retractor tube. Access device 310 as
shown in FIG. 3A has an inner diameter of 7.0 mm and an outer
diameter of 9.5 mm. At this stage, orientation of camera 320 is
biased to one side (left side in figure). During insertion, the
electrode 340 on the side opposite the viewing field of the camera
(right side in figure) is distally translated so that it emerges
distally from the distal tip of the device 300. Also during
insertion, the distally translated electrode 340 is activated by
supplying RF current and irrigating conducting fluid, resulting in
tissue dissection during insertion of the device. For further
tissue dissection on the side to which the camera is biased (left
side in figure), the electrode 340 on the same side as the viewing
field of the camera (left side in figure) is distally translated so
that it emerges laterally from the endoscope probe on the proximal
side of the camera. While being translated, the same electrode
(left side in figure) is activated by supplying RF current and
irrigating conducting fluid, resulting in tissue dissection. At
this point, the entire end of the device 300 may be translated
proximally and distally until the desired tissue dissection is
obtained. When finished with tissue dissection at the first
location, the device may be rotated 180 degrees and further tissue
removed using the steps described above.
Utility
[0085] The subject tissue modification devices and methods find use
in a variety of different applications where it is desirable to
image and/or modify an internal target tissue of a subject while
minimizing damage to the surrounding tissue. The subject devices
and methods find use in many applications, such as but not limited
to surgical procedures, where a variety of different types of
tissues may be removed, including but not limited to: soft tissue,
cartilage, bone, ligament, etc. Specific procedures of interest
include, but are not limited to, spinal fusion (such as
Transforaminal Lumbar Interbody Fusion (TLIF)), total disc
replacement (TDR), partial disc replacement (PDR), procedures in
which all or part of the nucleus pulposus is removed from the
intervertebral disc (IVD) space, arthroplasty, and the like. As
such, methods of the invention also include treatment methods,
e.g., where a disc is modified in some manner to treat an existing
medical condition. Treatment methods of interest include, but are
not limited to: annulotomy, nucleotomy, discectomy, annulus
replacement, nucleus replacement, and decompression due to a
bulging or extruded disc. Additional methods in which the imaging
devices find use include those described in United States Published
Application No. 20080255563.
[0086] In certain embodiments, the subject devices and methods
facilitate the dissection of the nucleus pulposus while minimizing
thermal damage to the surrounding tissue. In addition, the subject
devices and methods can facilitate the surgeon's accessibility to
the entire region interior to the outer shell, or annulus, of the
IVD, while minimizing the risk of cutting or otherwise causing
damage to the annulus or other adjacent structures (such as nerve
roots) in the process of dissecting and removing the nucleus
pulposus.
[0087] Furthermore, the subject devices and methods may find use in
other procedures, such as but not limited to ablation procedures,
including high-intensity focused ultrasound (HIFU) surgical
ablation, cardiac tissue ablation, neoplastic tissue ablation (e.g.
carcinoma tissue ablation, sarcoma tissue ablation, etc.),
microwave ablation procedures, and the like. Yet additional
applications of interest include, but are not limited to:
orthopedic applications, e.g., fracture repair, bone remodeling,
etc., sports medicine applications, e.g., ligament repair,
cartilage removal, etc., neurosurgical applications, and the
like.
[0088] Devices of the invention may provide variable tactile
feedback to the operator depending on tissue type. For example, in
embodiments where a distal end structure, such as a tissue modifier
(e.g., a RF electrode) is linearly translated by a mechanical
linear actuator (e.g., as described above), the operator may
experience different tactile properties depending on the type of
tissue that is being contacted by the linearly translating distal
end structure. These different tactile properties may then be
employed by the user to differentiate between different types of
tissue. In other words, devices of invention may provide different
sensations to an operator, such as a surgeon, during use depending
on the nature of the tissue with the distal end of the device is in
contact. As such, devices and methods of the invention also find
use in tissue discrimination applications, where the devices are
employed to determine the particular nature of the internal tissue
with which the distal end of the device is in contact, e.g.,
whether the distal end of the device is in contact with soft
tissue, cartilage, bone, etc.
[0089] As reviewed above, in some embodiments synchronization of
the tissue modifier's modulation waveform with its linear
translation waveform provides additional benefits. For instance,
rapid retraction of the electrode from hard tissue that it
encounters will leave the tissue modifier physically separated from
the hard tissue by a gap as the tissue modifier approaches the
proximal extreme position. In some embodiments, the tissue modifier
tip is activated only when the tissue modifier is at or near the
proximal extreme position, as mentioned above. This has the effect
of preferentially delivering the tissue modification energy to
soft, compliant tissue as opposed to hard, stiff tissue. Stated
otherwise, this provides tissue discrimination based on elastic
modulus. In the case of spinal surgery applications requiring
removal of nuclear material, such as fusion, total disc
replacement, and partial disc replacement, synchronization of the
modulation waveform with the linear translation waveform
facilitates the delivery of tissue modification energy to the
nucleus pulposus (soft, compliant tissue) while minimizing the
delivery of tissue modification energy to the disc annulus (hard,
stiff tissue) and the endplates of the vertebral bodies (hard,
stiff tissue). In addition, cyclic linear translation of the tissue
modifier helps to prevent a condition where the electrode sticks to
tissue as it ablates it, resulting in increased thermal effects to
the surrounding tissue, ineffective or discontinuous tissue
dissection, buildup of charred or otherwise modified tissue on the
tissue modifier tip, or a combination thereof. Additionally, cyclic
linear translation of the tissue modifier helps chop the dissected
tissue into smaller pieces, thus facilitating aspiration of the
dissected tissue.
Kits
[0090] Also provided are kits for use in practicing the subject
methods, where the kits may include one or more of the above
devices, and/or components of the subject systems, as described
above. The kit may further include other components, e.g.,
guidewires, access devices, fluid sources, etc., which may find use
in practicing the subject methods. Various components may be
packaged as desired, e.g., together or separately.
[0091] In addition to above mentioned components, the subject kits
may further include instructions for using the components of the
kit to practice the subject methods. The instructions for
practicing the subject methods are generally recorded on a suitable
recording medium. For example, the instructions may be printed on a
substrate, such as paper or plastic, etc. As such, the instructions
may be present in the kits as a package insert, in the labeling of
the container of the kit or components thereof (i.e., associated
with the packaging or subpackaging) etc. In other embodiments, the
instructions are present as an electronic storage data file present
on a suitable computer readable storage medium, e.g. CD-ROM,
diskette, etc. In yet other embodiments, the actual instructions
are not present in the kit, but means for obtaining the
instructions from a remote source, e.g. via the internet, are
provided. An example of this embodiment is a kit that includes a
web address where the instructions can be viewed and/or from which
the instructions can be downloaded. As with the instructions, this
means for obtaining the instructions is recorded on a suitable
substrate.
[0092] Although the foregoing invention has been described in some
detail by way of illustration and example for purposes of clarity
of understanding, it is readily apparent to those of ordinary skill
in the art in light of the teachings of this invention that certain
changes and modifications may be made thereto without departing
from the spirit or scope of the appended claims. It is also to be
understood that the terminology used herein is for the purpose of
describing particular embodiments only, and is not intended to be
limiting, since the scope of the present invention will be limited
only by the appended claims.
[0093] Accordingly, the preceding merely illustrates the principles
of the invention. It will be appreciated that those skilled in the
art will be able to devise various arrangements which, although not
explicitly described or shown herein, embody the principles of the
invention and are included within its spirit and scope.
Furthermore, all examples and conditional language recited herein
are principally intended to aid the reader in understanding the
principles of the invention and the concepts contributed by the
inventors to furthering the art, and are to be construed as being
without limitation to such specifically recited examples and
conditions. Moreover, all statements herein reciting principles,
aspects, and embodiments of the invention as well as specific
examples thereof, are intended to encompass both structural and
functional equivalents thereof. Additionally, it is intended that
such equivalents include both currently known equivalents and
equivalents developed in the future, i.e., any elements developed
that perform the same function, regardless of structure. The scope
of the present invention, therefore, is not intended to be limited
to the exemplary embodiments shown and described herein. Rather,
the scope and spirit of present invention is embodied by the
appended claims.
* * * * *