U.S. patent application number 10/813283 was filed with the patent office on 2004-09-30 for surgical instrument for ablation and aspiration.
This patent application is currently assigned to Oratec Interventions, Inc.. Invention is credited to Ashley, John, Reyes, Ramiro L., Sharkey, Hugh R., Stewart, Daren L., Strul, Bruno.
Application Number | 20040193150 10/813283 |
Document ID | / |
Family ID | 23634856 |
Filed Date | 2004-09-30 |
United States Patent
Application |
20040193150 |
Kind Code |
A1 |
Sharkey, Hugh R. ; et
al. |
September 30, 2004 |
Surgical instrument for ablation and aspiration
Abstract
An electrosurgical aspiration instrument that permits aspiration
of an area being treated by the instrument. The instrument is
coupled at a proximal end to a power source and includes an energy
application surface area at a distal end. The power source supplied
energy to the energy application surface area such that the distal
end of the instrument may apply energy to the treatment area to
modify the characteristics of biological material, such as
biological tissue in the area. An aspiration lumen is formed
through the instrument with an opening through the energy
application surface area. The energy application surface area is
configured to reduce blockage of the opening. Accordingly,
aspiration may be performed simultaneously with electrosurgical
treatment whereby unwanted matter such as by-products, biological
debris and excess fluid is removed from the treatment area. The
electrosurgical aspiration instrument also permits both functions
to be performed at different times, with the advantage of not
requiring instruments to be switched on during the treatment
procedure or removed from the treatment site.
Inventors: |
Sharkey, Hugh R.; (Woodside,
CA) ; Strul, Bruno; (Portola Valley, CA) ;
Stewart, Daren L.; (Belmont, CA) ; Ashley, John;
(San Francisco, CA) ; Reyes, Ramiro L.; (Union
City, CA) |
Correspondence
Address: |
Joel R. Petrow, Esq.
Smith & Nephew, Inc.
1450 Brooks Road
Memphis
TN
38116
US
|
Assignee: |
Oratec Interventions, Inc.
|
Family ID: |
23634856 |
Appl. No.: |
10/813283 |
Filed: |
March 31, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10813283 |
Mar 31, 2004 |
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09895609 |
Jun 29, 2001 |
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09895609 |
Jun 29, 2001 |
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09412878 |
Oct 5, 1999 |
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6379350 |
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Current U.S.
Class: |
606/41 |
Current CPC
Class: |
A61B 2018/00595
20130101; A61B 2018/126 20130101; A61B 2018/00083 20130101; A61B
2018/1253 20130101; A61B 2218/008 20130101; A61B 2218/007 20130101;
A61B 2018/00136 20130101; A61B 2018/00589 20130101; A61B 2018/1435
20130101; A61B 2018/0091 20130101; A61B 2018/162 20130101; A61B
2218/002 20130101; A61B 2018/00577 20130101; A61B 18/1402 20130101;
A61B 2018/00625 20130101; A61B 2018/00011 20130101; A61B 2018/00601
20130101 |
Class at
Publication: |
606/041 |
International
Class: |
A61B 018/14 |
Claims
1-40. (Cancelled)
41. A surgical instrument comprising: a shaft having distal and
proximal ends, the shaft defining a lumen; a conductive member
disposed at the distal end of the shaft across the lumen and
forming an electrode, the conductive member having an opening
therethrough communicating with the lumen for aspirating material
through the conductive member, the opening being smaller than a
diameter of the lumen to avoid clogging of aspirated material
downstream of the opening, the conductive member having an ashtray
shape; and a conductor connected to the conductive member.
42. The surgical instrument of claim 41 further comprising: a
second electrode disposed on the shaft proximally from the
electrode; and a second conductor connected to the second
electrode.
43. The surgical instrument of claim 42 wherein the second
electrode is disposed around the shaft proximally from the
electrode.
44. The surgical instrument of claim 41 wherein the electrode
further comprises a sharp edge forming a mechanical treatment
surface.
45. The surgical instrument of claim 41 wherein the electrode
includes a mechanical treatment surface having an edge configured
to form a high current density at the edge for an ablative effect
along the edge.
46. The surgical instrument of claim 41 wherein the lumen has
multiple diameters.
47. A surgical instrument for use with a power source, the surgical
instrument comprising: a shaft having distal and proximal ends, the
shaft defining a lumen; a conductive member disposed at the distal
end of the shaft across the lumen to define an energy application
plane across the lumen and forming an electrode, the conductive
member having an opening therethrough communicating with the lumen
for aspirating material through the conductive member across the
energy application plane, the opening being smaller than a diameter
of the lumen to avoid clogging of aspirated material downstream of
the opening, the electrode having an ashtray shape and having a
mechanical treatment surface for the mechanical removal of tissue
at a surgical site; and a conductor connected to the conductive
member and adapted for coupling to the power source.
48. The surgical instrument of claim 47 further comprising: a
second electrode disposed on the shaft proximally from the
electrode; and a second conductor connected to the second
electrode.
49. The surgical instrument of claim 48 wherein the second
electrode is disposed around the shaft proximally from the
electrode.
50. The surgical instrument of claim 48 wherein one of the
conductor and the second conductor is formed by the shaft.
51. The surgical instrument of claim 47 wherein the lumen has an
insulative coating.
52. The surgical instrument of claim 47 further comprising a
suction source coupled to the proximal end of the shaft for
providing negative pressure to the lumen so as to cause matter to
be aspirated through the opening of the conductive member.
53. The surgical instrument of claim 47 wherein the mechanical
treatment surface is an edge, provided on the electrode, configured
to form a high current density to provide an electrical and
mechanical effect.
54. The surgical instrument of claim 47 wherein the mechanical
treatment surface includes a sharp edge.
55. The surgical instrument of claim 47 wherein the electrode is
concentrically disposed at the distal end of the shaft.
56. The surgical instrument of claim 47 wherein the proximal end of
the shaft is mounted to a handle, the handle providing a connection
for the conductor to a power supply and a connection for the lumen
to a vacuum source.
57. The surgical instrument of claim 47 wherein the lumen has
multiple diameters.
58. A surgical device comprising: an elongated shaft defining a
lumen; a first electrode coupled to the elongated shaft and forming
a tissue treatment surface configured to treat tissue, the tissue
treatment surface defining at least part of a lumen opening in
communication with the lumen; and a second electrode coupled to the
elongated shaft and electrically isolated from the first
electrode.
59. The surgical device of claim 58 wherein the second electrode
comprises an exposed portion not disposed around an entirety of a
circumference of the elongated shaft, the exposed portion being
disposed entirely proximal of the first electrode, and the surgical
device further comprises an insulator extending longitudinally
along an entire side of the elongated shaft such that non-target
tissue adjacent the insulator is insulated during
electrosurgery.
60. The surgical device of claim 58 wherein the second electrode
includes an exposed portion not disposed around an entirety of a
circumference of the elongated shaft.
61. The surgical device of claim 58 further comprising an insulator
extending longitudinally along an entire side of the elongated
shaft such that non-target tissue adjacent the insulator is
insulated during electrosurgery.
62. The surgical device of claim 58 wherein the first electrode
defines the entire lumen opening.
63. The surgical device of claim 58 wherein the surgical device
comprises a distal end, and the lumen opening is at the distal
end.
64. The surgical device of claim 58 wherein: the lumen has at least
one diameter including a minimum lumen diameter, and the lumen
opening is smaller than the minimum lumen diameter to avoid
clogging of aspirated material downstream of the lumen opening.
65. The surgical device of claim 60 wherein the second electrode is
not disposed at all around the circumference of the elongated
shaft.
66. The surgical device of claim 60 wherein the second electrode is
disposed within the lumen.
67. The surgical device of claim 60 wherein the surgical device
includes a front face and the second electrode is disposed on the
front face.
68. The surgical device of claim 58 wherein the first and second
electrodes each face toward a common direction.
69. The surgical device of claim 68 wherein the common direction is
forward.
70. The surgical device of claim 58 wherein the first electrode is
forward-facing.
71. The surgical device of claim 58 wherein the first and second
electrodes are not disposed on opposite sides of the elongated
shaft.
72. The surgical device of claim 58 wherein the device has only two
electrodes.
73. The surgical device of claim 61 wherein the insulator comprises
a thermal and electrical insulator.
74. The surgical device of claim 61 wherein the insulator is
disposed over at least 45 degrees of a circumference of the
elongated shaft.
75. The surgical device of claim 61 wherein the surgical device
defines a return path for current that does not go under the
insulator.
76. The surgical device of claim 58 wherein the first electrode
comprises a scraping surface configured to scrape tissue.
77. The surgical device of claim 76 wherein the first electrode is
configured in an ashtray configuration and the scraping surface
comprises an edge in the ashtray configuration.
78. The surgical device of claim 58 wherein: the elongated shaft
defines a longitudinal axis and comprises a distal portion, and the
first electrode is coupled to the distal portion of the shaft and
is configured to contact tissue straight-on along the longitudinal
axis.
79. The surgical device of claim 58 wherein: the first electrode is
configured to provide radio frequency energy to ablate tissue, and
the second electrode is configured to operate in a bipolar mode
with the first electrode.
80. The surgical device of claim 58 wherein the second electrode
comprises an exposed portion that is disposed entirely proximal of
the first electrode.
81. The surgical device of claim 58 wherein the entire second
electrode is disposed proximal of the first electrode.
82. A method of performing surgery, the method comprising: applying
electrical energy to a first electrode of a bipolar surgical device
to perform electrosurgery on a target tissue, the first electrode
being disposed on an elongated shaft of the bipolar device, the
bipolar device further including a second electrode; and
transferring fluid through a lumen and a lumen opening of the
surgical device, the lumen opening being in communication with the
lumen and being defined at least in part by a tissue treatment
surface formed by the first electrode.
83. The method of claim 82 wherein applying electrical energy
comprises applying electrical energy to a first electrode of a
bipolar surgical device in which the second electrode is not
disposed around an entirety of a circumference of the elongated
shaft.
84. The method of claim 83 further comprising providing an
insulating surface extending longitudinally along an entire side of
the elongated shaft, such that non-target tissue adjacent the
insulating surface is shielded during the application of electrical
energy to target tissue.
85. The method of claim 82 further comprising providing an
insulating surface extending longitudinally along an entire side of
the elongated shaft, such that non-target tissue adjacent the
insulating surface is shielded during the application of electrical
energy to target tissue.
86. The method of claim 85 wherein providing the insulating surface
comprises providing a thermally and electrically insulating
surface.
87. The method of claim 82 wherein applying electrical energy to
perform electrosurgery comprises ablating the target tissue.
88. The method of claim 82 wherein transferring fluid through the
lumen comprises aspirating fluid through the lumen.
89. The method of claim 82 further comprising scraping the target
tissue using a scraping surface on the first electrode.
90. The method of claim 82 further comprising inserting the bipolar
surgical device into a body such that the first electrode is
adjacent the target tissue.
91. A surgical device comprising: an elongated shaft defining a
lumen, and the surgical device defining a lumen opening in
communication with the lumen, the lumen opening being smaller than
a diameter of the lumen to avoid clogging of aspirated material
downstream of the lumen opening; a first electrode coupled to the
elongated shaft; and a second electrode coupled to the elongated
shaft and electrically isolated from the first electrode.
92. The surgical device of claim 91 wherein the second electrode is
not disposed around an entirety of a circumference of the elongated
shaft.
93. The surgical device of claim 91 further comprising an insulator
extending longitudinally along an entire side of the elongated
shaft such that non-target tissue adjacent the insulator is
insulated during electrosurgery.
94. The surgical device of claim 58 wherein the lumen has multiple
diameters.
Description
BACKGROUND
[0001] The present invention relates to electrosurgical instruments
and systems for treating a surgical site on a human or animal body
such as biological tissue by the application of energy. More
particularly, the invention relates to surgical devices and methods
for applying high frequency energy to modify the characteristics of
the tissue such as by ablation in combination with aspiration of
any by-products from a surgical site.
[0002] Numerous surgical instruments for the treatment of
biological tissue through the application of energy in a wide
variety of medical procedures are known in the art. For example,
U.S. Pat. No. 4,593,691 to Lindstrom et al., U.S. Pat. No.
4,033,351 to Hetzel, and U.S. Pat. No. 5,403,311 to Abele et al.
are examples of electrosurgical probes for use during an
electrosurgical procedure such as for cutting or ablating tissue.
U.S. Pat. No. 5,458,596 to Lax et al. shows an example of an
electrosurgical probe for the contraction of tissue by delivering
electrical energy to the treatment tissue. Also, U.S. Pat. No.
3,828,780 to Morrison and U.S. Pat. No. 5,277,696 to Hagen show
electrosurgical instruments which deliver electrical energy for
coagulation during surgical procedures.
[0003] The use of these instruments typically involves the
transmission of energy to a distal end of the electrosurgical probe
or instrument. The distal end is inserted into the body to a
surgical site of a patient to apply energy during the procedure.
The frequency, power, and voltage generated by the electrical
instrument and transmitted to the distal end are selected depending
on the type of procedure for which the instrument is being used.
For instance, such instruments are used for a variety of procedures
such as heating, softening, shrinking, cutting and ablating
tissue.
[0004] Because such instruments may be used for different
procedures, the tissue (or other body part) being treated may
respond differently depending on the treatment being performed. For
instance, if the instrument is used to ablate the tissue, smoke and
charring may be generated during the procedure or residual tissue
debris may remain after treatment. Unwanted air bubbles or excess
fluid may also be present in the treatment area that may interfere
with effective treatment of the tissue and should be removed from
the surgical site during the procedure. Thus, it is desirable to
provide an electrosurgical device for aspirating the region being
treated to remove smoke, tissue debris, excess fluid and other
unwanted matter from the tissue site being treated.
[0005] During the usage of prior instruments, however, such as in
numerous of the above-mentioned instruments, the removal of
unwanted matter generally requires the separate provision of an
aspiration device. The use of two separate instruments increases
the treatment time because the suction instrument must be
separately inserted into the surgical site, used, and removed from
the site before and/or after the electrosurgical treatment
instrument is inserted or used at the site. Additionally, a
separate suction instrument may be inserted into the surgical site
through another access point which creates another portal in the
patient's body which possibly creates further complications such as
infection and scarring.
[0006] U.S. Pat. No. 5,520,685 to Wojciechowicz, U.S. Pat. No.
4,682,596 to Bales and U.S. Pat. No. 4,347,842 to Beale disclose
suction devices in various combinations and configurations with the
electrosurgical probe. U.S. Pat. No. 5,195,959 to Smith also
discloses an electrosurgical device with suction and irrigation to
supply electrically conductive fluid which adds even more material
to the surgical site and would need to be removed during the
procedure. Wojciechowicz, in particular discloses a suction
coagulator with a suction lumen for the suction of by-products of
electrosurgery through the instrument through a tip. Further, Hagen
discloses a suction device for aspirating fluid through the
surgical probe.
[0007] However, the arrangement of the suction lumen in
relationship to the electrosurgical portion is such that blockage
or clogging of the suction lumen can occur which could complicate
the surgical procedure and unwanted or unnecessary ablation could
occur. Charred and ablated tissue and coagulated blood often clog
the tips of electrosurgical devices.
[0008] Therefore, it would be desirable to provide an instrument
that may be used not only to treat a patient but also to aspirate
the treatment area during treatment to simultaneously remove
unwanted material. The surgical device and method should be simple
and operate in a standard surgical environment. The electrosurgical
instrument should provide the surgeon the ability to ablate, cut or
coagulate in the same device while providing a suction means to
aspirate surgical by-products from the surgical site. The suction
and aspiration should be anti-clogging such that the device does
not cause unwanted nor undesirable effects due to blockage. Such
instrument and method should be able to precisely treat biological
tissue with energy while efficiently allowing the surgeon to
perform the medical procedure quickly without the need to utilize
multiple instruments for the treatment.
SUMMARY
[0009] It is, therefore, an object of the present invention to
provide a surgical instrument and method for the application of
energy to a treatment area of a patient and for the aspiration of
unwanted matter, such as smoke, air bubbles and biological waste
debris from the surgical site.
[0010] It is a related object of the present invention to provide a
combination of electrosurgical and aspiration instrument that
provides an energy application surface area that applies energy
uniformly over the treatment area and also permits aspiration
therethrough so as to limit clogging.
[0011] It is another object of the present invention to provide a
combination electrosurgical and aspiration instrument having both
an active electrode and a return electrode at a distal tip of the
instrument such that energy distribution is substantially limited
to the distal tip surface.
[0012] These and other objects and features are accomplished in
accordance with the principles of the present invention by
providing a probe having a cannula with at least one electrode for
the transmission and application of energy to a treatment site
along an energy application surface as well as a suction lumen
through which unwanted matter and surgical by-products may be
aspirated from the treatment area. Preferably, at least one
electrode, an active electrode is provided on a distal end of the
probe. A return or indifferent electrode may located on the
patients' body or on the probe. The instrument is coupled to an
energy generator that preferable includes controls that may be used
to regulate the power, frequency, and voltage applied to the
instrument to vary the type of treatment for which the instrument
is used. The regulation may include feedback controls.
[0013] In one embodiment of the invention, the active electrode is
provided with a plurality of small passages therethrough in a fluid
communication with the suction lumen of the instrument. An active
electrode with such aspiration passages may be in the form of a
mesh, a disc having perforations therethrough, or plural conductors
supported by an insulator with apertures therethrough. Thus,
aspiration of the treatment area occurs through at least a portion
of the energy application surface. If desired, both the active and
return electrodes may be positioned in substantially the same plane
such that energy distribution is substantially restricted to a
substantially planar surface area, such as the surface area of the
distal tip.
[0014] In an alternative embodiment of the present invention, the
surgical instrument has a shaft having distal and proximal ends.
The shaft also defines at least one lumen. The lumen has at least
one aspiration opening at the distal end. An active electrode is
located at the distal end of the shaft which defines an energy
application surface. The active electrode is electrically coupled
to a power source. A return electrode is coupled to the power
supply such that a current path from the active electrode to the
return electrode passes over the aspiration opening to prevent
clogging of the opening. The return electrode may be located on a
portion of the body of a patient or on the shaft.
[0015] As negative pressure is applied to the lumen, matter that is
in the surgical site is aspirated through the aspiration opening.
The opening is configured to prevent clogging of the aspirated
matter at the distal end. The aspiration opening may be defined by
the active electrode which is configured to prevent clogging of the
aspiration opening and allow continued desiccation of the unwanted
aspirated matter such that the matter will move easily through the
aspiration lumen.
[0016] These and other features and advantages of the present
invention will be readily apparent from the following drawings and
detailed description of the invention, the scope of the invention
being set out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The detailed description will be better understood in
conjunction with the accompanying drawing, wherein like reference
characters represent like elements, as follows:
[0018] FIG. 1 is a perspective view of an electrosurgical
aspiration instrument formed in accordance with the principles of
the present invention;
[0019] FIG. 2 is a cross-sectional view along axis A-A of FIG.
1;
[0020] FIG. 3 is an end view of a distal tip of the instrument of
FIG. 1;
[0021] FIG. 4 is an end view of a distal tip of the instrument of
FIG. 1 showing an alternative tip embodiment;
[0022] FIG. 5 is a perspective view of an electrosurgical
aspiration instrument according to the present invention with a
distal tip active electrode having a convex configuration;
[0023] FIG. 6 is a perspective view of an electrosurgical
aspiration instrument according to the present invention with a
distal tip active electrode having a concave configuration;
[0024] FIG. 7 is a cross-sectional view of a basic distal tip
portion of the instrument of FIGS. 5 and 6.
[0025] FIGS. 8A and 8B are cross-sectional and end views,
respectively, of an electrosurgical aspiration instrument showing
one embodiment of an active electrode in a coil configuration with
an internal return electrode;
[0026] FIGS. 9A and 9B are cross-sectional and end views,
respectively, of an electrosurgical aspiration instrument according
to the present invention showing an active electrode in a ring
configuration with an internal return electrode;
[0027] FIGS. 10A and 10B are cross-sectional and end views,
respectively, of an electrosurgical aspiration instrument according
to the present invention showing one embodiment of an active
electrode in a prong configuration with an internal return
electrode;
[0028] FIGS. 11A-C are cross-sectional and perspective views,
respectively, of an electrosurgical aspiration instrument according
to present invention having a mechanical grating configuration of
the active electrode with an external return electrode; FIG. 11A is
a ring grating configuration; FIG. 11B is a rasp grating
configuration;
[0029] FIGS. 12A and 12B are cross-sectional and perspective views,
respectively, of an electrosurgical aspiration instrument with an
alternative embodiment showing an active electrode having a cross
configuration for mechanical grating and delivery of energy;
[0030] FIGS. 13A and 13B are cross-sectional and perspective views,
respectively, of an alternate aspiration instrument of FIGS. 12A
and 12B with an active electrode having an ashtray configuration
for mechanical grating and energy delivery with an internal return
electrode;
[0031] FIGS. 14A and 14B are cross-sectional and perspective views,
respectively, of the instrument of FIGS. 13A and 13B showing an
external return electrode;
[0032] FIGS. 15A-C are detailed perspective, end, and
cross-sectional views of the distal tip of an electrosurgical
aspiration instrument according one embodiment of the present
invention; FIG. 15A is a detailed perspective view of an active
electrode with an aspiration opening; FIG. 15B is an end view of
the active electrode; and FIG. 15C is a cross-sectional view along
line A-A of the active electrode of FIG. 15B;
[0033] FIGS. 16A and 16B are cross-sectional and perspective views
of an alternative embodiment of the instrument present invention
wherein the distal tip is a true bipolar configuration having a
single aspiration opening;
[0034] FIGS. 17A and 17B are perspective and cross-sectional views
of an alternate embodiment of the instrument according to the
present invention showing a true bipolar configuration of the
distal tip having multiple aspiration openings;
[0035] FIGS. 18A-C are cross-sectional, end and perspective views
of an alternative embodiment of the distal tip having a single
aspiration opening with both active and return electrodes formed by
loop prongs defining the energy application surface;
[0036] FIG. 19 is a perspective view of the complete
electrosurgical instrument of the present invention showing a probe
having a handle and a shaft with a distal tip for treatment with a
suction line and control; and
[0037] FIGS. 20 and 21 are alternative embodiments of the distal
end shaft of FIG. 19 according to the present invention having a
pre-bent distal end in a 30 degree configuration and a 90 degree
configuration, respectively.
DETAILED DESCRIPTION OF THE INVENTION
[0038] An embodiment of an electrosurgical aspiration instrument 10
capable of aspirating a patient treatment area within a standard
surgical environment in accordance with the principles of the
present invention is illustrated in FIGS. 1 and 2. Electrosurgical
aspiration instrument 10 is in the form of a probe having,
generally, a shaft 27 disposed along longitudinal axis A-A, a
distal end 12 at which treatments are performed and a proximal end
14 at which instrument 10 is coupled to a power source (not shown)
via power line 16. Power line 16 supplies energy to distal end 12
for treatment. The power source preferably permits modification and
adjustment of the power, frequency, and voltage of the energy
transmitted to distal end 12. A handle 17 may be provided to
facilitate grasping of instrument 10 adjacent proximal end 14. At
least one actuator 18, such as an aspiration control valve or
switch or a power button may be provided. In a preferred
embodiment, a foot pedal (not shown) is provided to control power
supplied to distal end 12 and actuator 18 controls aspiration
through the instrument. Additional actuators or controllers, such
as for adjusting the power, frequency, or voltage, may be provided
either on instrument 10 itself or on the power source if
desired.
[0039] Electrosurgical aspiration instrument 10 has an energy
application surface or plane 20 formed by at least one electrode
that applies energy to the patient area to be treated. In one
embodiment, instrument 10 has at least two electrodes, active
electrode 22 and return electrode 24 that cooperate to apply energy
across surface 20. Electrodes 22 and 24 are formed from
electrically conductive materials, for example a medical grade
stainless steel, capable of withstanding the high temperatures
resulting from use of instrument 10. It will be appreciated that
the material that is selected for electrodes 22 and 24 has defined
conductivity characteristics that affects the power necessary to
achieve the desired treatment operation.
[0040] As shown in FIGS. 1 and 2, active electrode 22 is positioned
at the open distal end of shaft 27 of electrosurgical aspiration
instrument 10. Although shaft 27 may be a separate element,
preferably, return electrode 24 serves a dual purpose as both the
return electrode that completes the energy circuit with active
electrode 22 as well as the shaft of instrument 10. It will be
appreciated that the arrangement of electrodes 22 and 24 may be
reversed, such that the active electrode is in the form of a shaft
with an open distal end on which the return electrode is
positioned. Alternatively, the return electrode may be located on a
point external to the treatment site such as placing a grounding
pad or plate on the body (not shown).
[0041] Power is transmitted to active electrode 22 from power line
16 via a conductive element 26, such as a wire, as shown in FIG. 2.
Return electrode 24, as described above, is preferably in the form
of an electrically conductive shaft, preferably formed from 304
stainless steel or any other biocompatible conductive material,
that extends from distal end 12 of instrument 10 to proximal end
14. The end of return electrode 24 adjacent proximal end 14 of
instrument 10 is coupled to the power source to communicate the
power source at proximal end 14 with distal treatment end 12 and
thereby to complete the energy supply circuit of electrosurgical
aspiration instrument 10. If desired, the shaft forming a return
electrode 24 may be formed from a malleable material so that it is
shapeable by the user. However, the distal-most end of instrument
10 should not be flexible. Additionally, any bend imparted to
instrument 10 should not be so extreme as to close off the lumen
formed therethrough and described in further detail below.
[0042] Electrodes 22 and 24 are electrically isolated from each
other such that electrical arcing between active electrode 22 and
return electrode 24 generates treatment energy along energy
application surface 20 that may be applied to the patient.
Electrical isolation or insulation of electrodes 22 and 24 at
energy application surface 20 may be accomplished by the provision
of insulator 28 therebetween. Insulator 28 is formed from many
desired insulative material, such as ceramic, teflon or pyrolytic
carbon, that may withstand the high temperatures that may result
upon application of energy at distal end 12 during use of the
instrument 10. Preferably, active electrode 22, return electrode
24, and insulator 28 permit fluid communication through instrument
10 from the treatment area at which energy application surface 20
is applied to proximal end 14, as described in further detail
below.
[0043] In addition, electrodes 22 and 24 must also be electrically
isolated axially along longitudinal axis 11 between proximal end 14
(at which instrument 10 applies treatment energy) so that power
supply to energy application surface 20 is not shorted. Although
insulation on wire 26 is typically sufficient to electrically
insulate active electrode 22 from return electrode 24, optional
insulation 30 on interior surface 32 of return electrode 24 may be
provided. Insulation 30 is selected from biocompatible and
electrically insulative material which could include nylon,
polyimide or other shrink tubing and also functions to limit the
heat transfer to the shaft. If active electrode 22 (rather than
return electrode 24) is coupled to the power source via a
conductive shaft as mentioned above and described with respect to
the embodiments of FIGS. 8-11, insulation 30 would be more
desirable. An insulative cover 34, such as formed from a teflon
coating or a heat shrink cover, is provided over exterior surface
36 of return electrode 24 to restrict the extent of arcing and
hence energy supplied to distal treatment end 12 of instrument
10.
[0044] Instrument 10 may be substantially straight, or may have a
slight bend at distal end 12 such that energy application surface
20 is slightly offset form longitudinal axis 11. As shown in FIGS.
1 and 2, the energy application surface 20 of electrosurgical
aspiration instrument 10 extends along distal end 12 (approximately
transverse to longitudinal axis A-A in a straight instrument).
However, it will be appreciated that electrodes 22 and 24 may be
provided at different positions at distal end 12 to alter the
location of energy application surface 20.
[0045] Electrosurgical aspiration instrument 10 may be used for a
variety of electrosurgical treatments. On particular use of
instrument 10 is for ablation of human or animal tissue. Because
ablation generally occurs at very high temperatures, e.g. 300-1000
degrees Celsius, smoke and/or vapor may be generated during
ablation. It may be desirable to remove smoke; unwanted or excess
gases, such as air bubbles; fluids, such as irrigation fluid
required to irrigate or enhance conduction after treatment; from
the treatment area during treatment. Moreover, debris or other
materials or biological elements may remain after the ablation
procedure that should be removed from the treatment area. Thus, in
accordance with the principles of the present invention, instrument
10 is also designed to aspirate such unwanted matter from the
treatment area during the electrosurgical procedure performed
thereby. It will be appreciated that aspiration may be performed
either simultaneously with, before, or after electrosurgical
treatment of an area. Further, it should be appreciated that a
power source may be used which sequentially, or in a predetermined
sequence, supplies power to the active electrode and then provides
power for aspiration. Accordingly, an aspiration lumen 50 is
provided within electrosurgical aspiration instrument 10 along
longitudinal axis A-A. Aspiration lumen 50 may be formed by
interior wall or surface 32 of return electrode 24 and is in fluid
communication with a aspiration line 52 which couples proximal end
14 of instrument 10 with a vacuum source of other aspiration device
(not shown). Aspiration line 52 is preferably standard tubing for
connection to a suction source and device.
[0046] In order to facilitate aspiration during electrosurgical
treatment, such as during ablation or coagulation, instrument 10 is
provided with an aspiration means which permits aspiration through
energy application surface 20. This is accomplished by providing at
least one through-hole or aperture 25 through active electrode 22
which defines surface 20. Alternatively, a plurality of
through-holes or apertures through active electrode 22 may be used
to aid in aspiration of the electrosurgical probe. In the
embodiment of FIGS. 1 and 2, active electrode 22 is in the form of
a wire mesh or screen 22A supported by an electrically conductive
ring 22B. Mesh 22A and ring 22B comprising active electrode 22 are
formed from a conductive materials, such as stainless steel,
tungsten, or titanium or their alloys, that can withstand the high
temperatures resulting from use of instrument 10. The entire mesh
and ring of active electrodes 22 serves as the energy application
surface and is powered by the power supply so that the
electrosurgical application, such as ablation, occurs over the
electrode. Thus, the active aspiration is approximately
co-extensive with energy application surface 20. The preferred
range of mesh sizes is from approximately 30 mesh to approximately
55 mesh.
[0047] The interstices between the mesh permit fluid communication
therethrough such that unwanted matter (e.g., ablated tissue,
smoke, air bubbles, and other elements or biological debris) may
pass through the mesh and into aspiration lumen 50 for transport
away form the treatment area. Moreover, because power is supplied
substantially uniformly over the entire mesh of active electrode
22, unwanted matter that is too large to fit through the
interstices of the mesh are caught on the mesh and accordingly
ablated thereby when power is applied to the electroconductive
mesh. As the mesh heats up, the matter is ablated until it becomes
small enough to fit through the mesh. It will be appreciated that
the energy application surface has a uniform electrical potential
being one piece across the surface of the mesh. Additionally, a
blockage occurring at one portion of the mesh causes an increase in
the suction force at unblocked portions of the mesh forming a
non-uniform suction path. As the suction force increases in the
unblocked areas, a differential axial suction force is created in
which the blockage is turned and twisted to continue ablation and
pass through apertures 25 to be aspirated through aspiration lumen
50. Thus, active electrode 22 not only provides treatment energy
but also permits aspiration therethrough, as well as destruction of
larger pieces of unwanted matter during aspiration which might
otherwise clog the aspiration lumen 50.
[0048] Moreover, in the present embodiment, return electrode 24 is
located on shaft 27 proximal to active electrode 22. This defines a
unipolar configuration where the return electrode 24 has a larger
surface area than active electrode 22 functions as an indifferent
return to the power source and the energy is diffuse around
electrode 24. This provides the active electrode 22 with a higher
current density such that treatment energy is crowded and the
treatment effect is generally in the area of tissue in proximity to
active electrode 22. In an alternative embodiment, however, return
electrode 24 may be located on a surface on the patient's body in
the form of a grounding plate or pad. In this configuration, the
return electrode functions to return the treatment energy to the
power source to define a monopolar configuration.
[0049] Referring to FIG. 3, the electrosurgical probe of FIGS. 1
and 2 is illustrated in an end view. Mesh 22A of active electrode
22 forms the energy application surface. The spacing between the
mesh form multiple apertures 25 to allows for suction of unwanted
matter through the distal end and aspiration opening. Although a
substantially flat piece of mesh may be used, the mesh may be
formed into any desired shape to vary the contour of the contact
surface provided by the mesh. For instance, the mesh forming active
electrode 22 may be domed to conform substantially with concave
body parts to be treated by electrosurgical aspiration instrument
10. Pointed, convex, rippled, or other contours may be provided
instead, depending on user preferences or other contours of the
area to be treated. Insulator 28 electrically isolates active
electrode 22 from return electrode 24.
[0050] In FIG. 4, instead of providing active electrode 22 in the
form of a mesh, active electrode 22 may take on an alternative form
with apertures provided to permit aspiration therethrough. For
example, active electrode 22 may be in the form of a disc or
conductive plate 42 with perforations 45 formed therethrough. In an
exemplary embodiment, such a plate may be secured within the distal
end of annular insulator 28 in place of mesh electrode 22 as shown
in FIG. 2. In a preferred embodiment, perforations 45 have a
diameter of approximately 0.010-0.020 inches. In general, the
perforations should be small enough to reduce particle size passing
therethrough such that downstream clogging is minimized while large
enough to provide effective aspiration without blockage of the
distal tip 12. Likewise, any other type of conductive element
formed as a honeycomb or other such shape that permits aspiration
therethrough may be used.
[0051] Alternative configurations of electrodes which define an
energy application surface and permit aspiration therethrough are
illustrated in FIGS. 5-7, as described below. It will be
appreciated that the form of the active electrode may be modified
as desired so long as external access to the internal lumen through
the shaft of the electrosurgical aspiration instrument of the
present invention is permitted. It will further be appreciated that
the form and relative arrangement of the active electrode with
respect to the return electrode may be modified as desired.
However, it is desirable that the resulting energy application
surface extends at least over a portion of the lumen opening to
permit cooperation between the energy application surface and the
process of aspiration. This provides for reduction in blockage.
[0052] Electrosurgical instrument 510 of FIG. 5 has a substantially
centrally located electrode 522 and a ring-shaped electrode 524
both of which are positioned at distal end 512 of instrument 510.
One of electrodes 522, 524 is an active electrode and the other of
electrodes 522, 524 is a return electrode. Both electrodes are
supported and electrically isolated by insulator 528. A suitable
insulative coating or covering 534 is provided over the exterior
surface of instruments 10. Apertures 525 permit aspiration as a
suction force is applied to aspiration lumen 550 to draw unwanted
matter through apertures and through the instrument 510.
[0053] As shown in FIG. 5, insulator 528 has a convex working
surface such that central electrode 522 is slightly distal of
ring-shaped electrode 524 to form a unipolar configuration.
However, it will be appreciated that a substantially flat working
surface my be used instead such that the energy application ends of
both electrodes are coplanar.
[0054] Alternatively, a concave working surface may be used, as in
electrosurgical instrument 610 of FIG. 6, such that ring-shaped
electrode 624 is slightly distal of central electrode 622. The
instrument 610 as shown in FIG. 6 includes apertures 625 within
insulator 628 for aspiration from the distal tip 612 through
aspiration lumen 650. Outer insulation 634 covers the instrument
shaft.
[0055] The arrangement and electrical connections of electrodes 522
and 524 of electrosurgical instrument 510 may be appreciated with
reference to FIG. 7. It will be understood that a similar
arrangement may be used for electrosurgical instruments 510 and 610
as well. In the exemplary embodiment, FIG. 7 illustrates a
cross-section through shaft 727 showing electrical power conductor
716, in the form of a wire extending proximally from a power source
(not shown) located at proximal end 714 to distal 712 of instrument
710. Power conductor 716 passes through lumen 750 and provides
power to central electrode 722. Electrical power conductor 736 is
in the form of shaft 727 being electrically conductive and
conductor 736 electrically coupled to return electrode 724 via
extension 736. Electrical conductors 716, 726, and 736 are
electrically isolated from each other in any desired manner, such
as in with insulative material such as interior insulation 730 in a
manner described above. An insulative coating or covering 734 is
provided on the exterior surface of instrument 710, preferably to
protect the patient from any energy discharge conducted through
electrical conductor 736.
[0056] Apertures 525, 625, and 725 are provided through insulator
528, 628 or 728, respectively, such that instruments 510, 610, and
710 also perform an aspiration function as previously described. In
particular, the apertures provide for aspiration through the energy
application surface which is defined by the electrode planes. It
will also be appreciated that certain advantages in localized
energy application may be realized due to the placement of both
electrodes on the distal tip of the device.
[0057] It should be appreciated that active electrode in FIGS. 5-7
can be sized appropriately, relative to return electrode or vice
versa, such that application of power to the active electrode and
use of the electrosurgical instrument approximates the effect
delivered by a bipolar electrosurgical instrument. In a typical
bipolar instrument, both electrodes are of the same size and
approximately located with in the same proximity such that both
electrodes equally affect the tissue area to which the instrument
is applied. By sizing the active electrode and the return electrode
to be of approximately equivalent sizes, a bipolar effect may be
achieved with the present invention. It should further be
appreciated that it is possible to size the electrodes in any of
the embodiments of the present invention so as to achieve a bipolar
effect. The return electrode of the present invention may also be
located on the patient's body as discussed above.
[0058] FIGS. 8A and 8B, FIGS. 9A and 9B and FIGS. 10A and 10B,
illustrate similar embodiments of the electrosurgical aspiration
instrument of the present invention. For the sake of simplicity,
descriptions of elements or features of the embodiments of FIGS.
8-10 that are substantially the same (and thus referenced by the
same reference numbers) are not repeated in detail, reference being
made to the description provided in connection with similar
elements described with reference to FIGS. 8-10.
[0059] FIGS. 8A and 8B illustrate one alternative embodiment of
electrosurgical instrument 810 having an active electrode 822 in
the form of a ringed coil on distal tip 812. The coil of active
electrode 822 may be preformed memory metal or a continuous wire
which is looped on distal tip 812.
[0060] FIG. 8A is a cross-sectional view showing coil active
electrode 822 on distal end 812. The outermost portion of coil
active electrode 822 defines energy application surface 820 which
forms both an energy treatment surface through the delivery of
energy and a mechanical grating surface. Electrode 822 is
preferably electrically connected through shaft 827 to the power
source through conductor 816. Electrode 822 is in the form of a
ring on the distal tip and defines aspiration aperture 825.
Insulative material 830 lines aspiration lumen 850 to provide both
electrical insulation from any stray electrical current and thermal
insulation of the shaft. Return electrode 824 is located internally
within aspiration lumen 850 and is electrically isolated from the
active electrode 822 by insulator 828 and insulation material 830.
Return conductor 826 connects the return electrode 824 to the power
source (not shown) at proximal end 814.
[0061] In this configuration, the internal return electrode 824
forms a small boiling chamber whereby any matter being aspirated
through aperture 825 and past active electrode 822 increases the
impedance to increase the delivery of energy in the region between
the electrodes. As the energy output from the power source
increases in response to the change in impedance, any matter
located between the electrodes is ablated to prevent blockage of
the aperture 825 and facilitate aspiration through aspiration lumen
850. As smaller matter and debris and any excess fluid pass freely
through aperture 825 and between the electrodes, the flow of
material cools both electrodes to prevent any hot spots or unwanted
ablative treatment effect.
[0062] Further, the internal return electrode 824 may provide a
benefit of localized heating within the distal end 812 of the
surgical instrument 810. As the suction force is applied through
aspiration lumen 850 and fluid and surgical by-products flow
through aperture 825, a pulling force is created within the local
environment surrounding the distal end 812 and active electrode
822. Similar to the blockage and cooling described above, the high
intensity energy delivery is limited to an area in close proximity
to the aperture 825. Thus, ablation and other surgical procedures
can be more precise since energy delivery is limited to the area
immediately surrounding aperture 825. The surgeon can control the
treatment by direct placement of distal end 812 and electrode 822
on the biological tissue and limit the ablative effect to the
tissue.
[0063] FIGS. 9A and 9B illustrate another alternative embodiment of
electrosurgical instrument 810 having an active electrode 922 in
the form of a ring electrode on distal tip 812. The ring electrode
configuration of active electrode 922 may be preformed memory metal
or a solid metal tip on distal tip 812. Electrode 922 is formed of
any biocompatible material including stainless steel, tungsten,
titanium or any of its respective alloys.
[0064] FIG. 9A is a cross-sectional view showing ring active
electrode 922 on distal tip 812. The outermost portion of the ring
active electrode 922 defines energy application surface 820 which
forms both an energy treatment surface through the delivery of
energy and a mechanical smoothing surface. In this embodiment, the
rounded surface provides a more diffuse energy application surface
than electrode 822 of FIG. 8. This provides a surgeon with the
ability to sculpt the body tissue by smoothing irregular areas by
passing the curved electrode 922 over the tissue. The electrode 922
may also be formed into a sharp edge to provide a mechanical
scraping surface for the removal of unwanted tissue. The electrical
current is then crowded for maximum ablative effect along the sharp
edge. Electrode 922 is preferably electrically connected through
shaft 827 to the power source through conductor 816. Electrode 922
is in the form of a ring on the distal tip and defines aspiration
aperture 825. Insulative material 830 lines aspiration lumen 850 to
provide both electrical insulation from any stray electrical
current and thermal insulation of the shaft. Return electrode 824
is located internally within aspiration lumen 850 and is
electrically isolated from the active electrode 922 by insulator
828 and insulation material 830. Return conductor 826 connects the
return electrode 824 to the power source (not shown) at proximal
end 814.
[0065] FIG. 9B is an end view of the distal tip of the instrument
of FIG. 9A. Active electrode 922 is shown as a ring around the
aspiration lumen to define aperture 825. Return electrode 824 is
shown within the aspiration lumen and is electrically isolated from
the active electrode 922 by insulator 828. Internal return
electrode 824 functions to form a boiling chamber as described
above.
[0066] FIGS. 10A and 10B illustrate another alternative embodiment
of electrosurgical instrument 810 having an active electrode 1022
in the form of a double prong on distal tip 812. The double prong
configuration of active electrode 1022 may be preformed memory
metal or a solid metal partial loop or coil on distal tip 812.
Electrode 1022 is formed of any biocompatible material including
stainless steel, tungsten, titanium or any of its respective
alloys.
[0067] FIG. 10A is a cross-sectional view showing prong active
electrode 1022 within insulator 828. The prong is preferably fixed
within insulator 828 such that one end is fixed within the
insulator 828 and a portion of the prong passes over aperture 825
to fix into the opposite side of the insulator 828. The outermost
edge portion of the prong active electrode 1022 defines energy
application surface 820 which forms both an energy treatment
surface through the delivery of energy and a mechanical treatment
surface. In this embodiment, a rounded prong surface provides a
smoothing function as described above. The prong active electrode
1022 may also be formed into a sharp edge to provide a mechanical
scraping surface for the removal of unwanted tissue. The electrical
current is then crowded for maximum ablative effect along the sharp
edge. Electrode 1022 is preferably electrically connected through
shaft 827 to the power source through conductor 816. Insulative
material 830 lines aspiration lumen 850 to provide both electrical
insulation from any stray electrical current and thermal insulation
of the shaft. Return electrode 824 is located internally within
aspiration lumen 850 and is electrically isolated from the active
electrode 1022 by insulator 828 and insulation material 830. Return
conductor 826 connects the return electrode 824 to the power source
(not shown) at proximal end 814.
[0068] FIG. 10B is an end view of the distal tip of the instrument
of FIG. 10A. Active electrode 1022 is shown as a prong passing over
aperture 825. In this embodiment, two prongs pass over the aperture
825 to prevent blockage of the aperture. Both electrode prongs are
electrically connected to the power source through a single
conductor 816 such that equal power is transmitted to active
electrode 822 at the same time for equal effect. It will be
appreciated that any number of prongs and the configurations may be
use. Return electrode 824 is shown within the aspiration lumen and
is electrically isolated from the active electrode 922 by insulator
828.
[0069] FIGS. 11A-C illustrate yet another embodiment of the present
invention in which the active electrode 1122 is formed from a
portion of shaft 1127. FIG. 11A shows a distal end 1112 with active
electrode 1122 forming an energy application surface 1120 for
treatment of body tissue at a surgical site. At proximal end 1114,
conductor 1116 connects the shaft to electrically activate the
active electrode 1122. Return electrode 1124 is located externally
to shaft 1127 and is electrically isolated from the active
electrode 1122 by insulator 1128. Preferably, return electrode 1124
is in the form of a ring electrode around a circumference of the
shaft 1127. Return conductor 1126 connects return electrode 1124 to
the power source. The return electrical path may also be located on
the patient's body as discussed previously. Shaft insulation 1134
covers shaft. 1127. The interior suction lumen 1150 may also be
lined with an insulative material.
[0070] An alternate embodiment of the active as shown in FIG. 11B
is similar to the electrosurgical aspiration instrument of FIG. 11A
where like elements are described with the same reference numbers.
In this configuration, active electrode 1122 has cutouts 1129 to
form a grating surface with cutout edges 1180. By configuring the
active electrode with cutout edges, the active electrode 1122 forms
high current densities at the energy application surface 1120 such
that current is crowded at the edges 1180. Thus, maximum ablation
in combination with a mechanical cutting and grating effect is
achieved. Additionally, fluid may be delivered through the lumen to
be delivered to the site when connected to a fluid delivery source
and aspirated through the same lumen 1150 when connected to a
suction source.
[0071] FIG. 11C illustrates a perspective view of the
electrosurgical instrument of FIG. 11B. Edges 1180 protrude beyond
the shaft and insulator 1128 for both delivery of treatment energy
for ablation, cutting or coagulation and mechanical scraping for
removal of unwanted tissue. As the current is crowded at the edges
1180, the mechanical scraping and cutting is facilitated by
providing an ablative effect at a precise cutting point along the
tissue. In this embodiment, the treated tissue is then aspirated
through the aspiration lumen away from the surgical site.
[0072] FIGS. 12A and 12B illustrate another embodiment of the
present invention in which the active electrode is formed into a
cross-shape with aspiration provided through and around the arm
extensions. FIG. 12A shows a cross-section view of the active
electrode 1222 of electrosurgical instrument 1210. The active
electrode 1222 is located at the distal end 1212 of shaft 1227 of
instrument 1210. Shaft 1227 may be covered by shaft insulation
1234. Active electrode 1222 is connected to a power source (not
shown) by electrical conductor 1216. The arm extensions of active
electrode 1222 are mostly planar with the main body of the
electrode and extend outward to form edges 1280. Apertures 1225 are
formed between the arms of active electrode 1222. A middle portion
of active electrode 1222 may also be raised from the main body to
form a middle edge 1280. By raising edges 1280, the current is
crowded along the edges for increased electrical density at edges
1280 for an ablative effect. Edges 1280 may also be configured and
sharpened for a simultaneous mechanical scraping and grating effect
at the surgical site.
[0073] The placement of edges 1280 also prevents blockage of the
apertures 1225 as current is delivered to the active electrode. As
the current is crowded along edges 1280, any matter resulting from
the surgical site which is blocking the aperture 1225 increases the
impedance between edges 1280 causing an increase in power. As the
power increases, the treatment energy ablates the unwanted matter
into a smaller size to pass through the aperture. For example, if
unwanted matter blocks one quadrant of the aperture 1225, impedance
is increased along edge 1280 near the blockage. Since the force of
suction is equal through the apertures, the suction unequally
increases at the other quadrants thereby pulling the blockage along
various axial planes. The increased treatment energy delivery
ablates portions of the blockage to a point in which the unwanted
matter moves easily through any of the apertures. This effect is
similar to the mesh configuration of FIG. 1 in which the ablative
effect due to the electrode design across the aspiration aperture
opening assists in further ablation of any blockage or unwanted
material. The differential suction over the other non-blocked
apertures creates a differential axial aspiration effect thereby
assisting in removing the blockage.
[0074] Return electrode 1224 is located internally within
aspiration lumen 1250 to form a boiling chamber as described above.
The electrical energy is returned to the power source from return
electrode 1224 by return conductor 1226. The return electrode 1224
is electrically insolated from active electrode 1222 by insulator
1228.
[0075] FIG. 12B is a perspective view of the instrument 1212 of
FIG. 12A. In this embodiment, edges 1280 are raised to form a cup
or pocket for ablation. Edges 1280 function as both a mechanical
cutting surface edge and a current crowding edge for effective
ablation.
[0076] Another embodiment is illustrated by FIG. 13A in which
electrosurgical instrument 1310 has an ashtray configuration of the
active electrode 1322. Active electrode 1322 is located on the
distal end 1312 of shaft 1327. The instrument shaft may be covered
with shaft insulator 1334. Active electrode 1322 is in an ashtray
configuration where cutouts 1329 are formed in energy application
surface 1320. By forming cutouts 1329, edges 1380 are formed within
the energy application surface 1320 of active electrode 1322. Edges
1380 form both a mechanical tissue removal surface simultaneously
with a current crowding edge for maximum energy delivery effect.
Blockage of aperture 1325 can also be prevented and eliminated by
configuring active electrode 1322 with edges 1380 near the aperture
1325. Electrical conductor 1316 electrically couples the electrode
1322 to the power source (not shown). Active electrode 1322 is
configured with a central aperture 1325 which communicates with
aspiration lumen 1350. Return electrode 1324 is located within
aspiration lumen 1350 and is proximal to active electrode 1322 to
form a boiling chamber as described above. Insulator 1328 insulates
electrodes 1322 and 1324. An internal lining 1330 may also line
aspiration lumen 1350 to function as both an electrical and thermal
insulator.
[0077] FIG. 13B is a perspective view of FIG. 13A in which the
active electrode 1322 is show in the ashtray configuration. Cutouts
1329 within the electrode define edges 1380 for the mechanical and
electrical effect as described above. Aperture 1325 communicates
through instrument 1310 with aspiration lumen 1350.
[0078] FIG. 14A and 14B illustrate cross-sectional and perspective
views of an alternative embodiment of the electrosurgical
aspiration instrument 1310 as described FIGS. 13A and 13B. Similar
elements will be referenced to FIGS. 13A and 13B. In this
embodiment, return electrode 1424 is located external along the
shaft 1327. Return electrode 1426 electrically completes the
current path to the power source from the active electrode 1322.
The return electrode 1424 is preferably a ring electrode located on
the surface of shaft 1327 and is isolated from the active electrode
1322 by insulator 1328.
[0079] FIGS. 15A-C illustrate different views of ashtray electrode
according to one alternative embodiment of the active electrode as
described above. Like elements will be referenced by the same
reference numbers. FIG. I 5A shows a close-up perspective view of
active electrode 1522 in which at least one aperture 1525 is
provided through active electrode 1522. Active electrode 1522 is
configured to crowd the current creating a high current density
along a circumferential edge 1580. Edge 1580 defines energy
application surface 1520. Cutouts 1529 form a pattern along edge
1580 to maximize the current crowding. As the current is crowded
along edges 1580, a mechanical scraping and ablative effect occurs
simultaneously. Current is also crowded edge 1580 formed within
aperture 1525 to prevent blockage of the aperture. As energy is
applied to the active electrode, the sharp edge of surface 1580
provides both a surface for the delivery of RF power for ablation
while simultaneously providing a mechanical grating or scraping
surface for scraping tissue at the surgical tissue site. It will be
appreciated that edge 1580 of electrode 1520 may be rounded such
that a smoothing surface may be formed and sculpting may be
performed with the instrument of the present invention.
[0080] As by-products of ablation and/or coagulation are created at
the surgical site, negative pressure created by suction through the
lumen and electrosurgical instrument aspirates the additional
matter through aperture 1525. However, blockage and clogging of the
aperture 1525 may undesirably increase the ablation effect by
reducing the flow of liquid and tissue through aperture 1525.
By-products of surgery such as biological tissue debris could
result from the ablation and cutting process. As this matter
becomes dislodged and freely movable within the surgical site, the
biological tissue may completely block any and all apertures into
the instrument. Thus, the cooling effect due to the flow of matter
and liquid is reduced thereby increasing the delivery of treatment
energy to the site possibly causing unnecessary ablation and injury
to the patient.
[0081] To combat blockage and potential injury, edges 1580 may be
configured with reference to FIG. 12 wherein a portion of edges
1580 is configured and positioned near or within aperture 1525. As
the impedance increases due to blocked tissue within aperture 1525,
the tissue is further treated with energy at edges 1580 whereby the
tissue is further ablated to a size to fit through aperture 1525.
The irregular shape of aperture 1525 in combination with edges 1580
provides for non-uniform and non-round apertures such that both an
electrical and mechanical effect combine to prevent blockage within
the opening thereby increasing the efficiency of the
electrosurgical instrument 1510.
[0082] FIG. 15B shows an end view of the distal electrode tip 1512.
Energy application surface 1520 and edge 1580 are shown with
cutouts 1529. It will also be appreciated that the number, sizes
and placement of cutouts 1529 within surface 1520 may vary to
provide different ablation effects and patterns. The electrical
current is crowded and has the greatest density at surface 1520 and
edge 1580 such that ablation, cutting and/or coagulation occurs
along edge 1580.
[0083] FIG. 15C is a cross-sectional view of the distal tip of FIG.
15B in which the active electrode 1522 on distal end 1512 is shown
along Line A-A. The energy application surface 1520 is shown in
detail as a sharp edge 1580 with both an electrical effect for
ablation and mechanical effect for scraping. Edge 1580 is shown to
be intruding into a portion of aperture 1525 which leads to
aspiration lumen 1550. With reference to FIG. 12 above, the effect
of suction through a non-uniform configuration of aperture 1525
prevents the blockage and clogging of the aspiration opening such
that the negative pressure pulls the blockage into the lumen across
different axial planes. For example, as an unwanted by-product
matter hits aperture 1525, it lodges on a portion of edge 1580. As
the suction is applied to the lumen and through the opening, a
portion of the matter is pulled on the portions away from the
lodged portion along edge 1580. This allows the matter to twist and
turn in different axial planes whereby the unwanted matter moves
and has a different and more compatible physical orientation to
move through aperture 1525.
[0084] FIGS. 16A and B illustrate a further alternative embodiment
of the present invention in which the active and return electrodes
1622, 1624 lie in substantially the same plane of the energy
application surface 1620 at the distal end 1612 of instrument 1610
to define a true bipolar configuration. Such position of electrodes
1622 and 1624 may be accomplished by forming each electrode as an
arcuate element positioned on the distal end 1612 of instrument
1610. Electrodes 1622 and 1624 are supported by insulator 1628
which serves the additional function of electrically isolating
electrodes 1622 and 1624. Cutouts 1629 are formed in insulator 1628
to space apart and thus further electrically isolate electrodes
1622 and 1624. Central opening 1625 allows for aspiration.
[0085] Electrodes 1622 and 1624 are separately coupled to the power
source by separate respective conductive elements 1616 and 1626.
Conductive elements preferably extend from distal end 1612 to
proximal end 1614 of instrument 1610 through lumen 1650. Although
conductive elements 1616 and 1626 extend through the central
opening 1625 through insulator 1628 to be coupled with electrodes
1622 and 1624 on the distal-most end of insulator 1628, it will be
appreciated that other arrangements are also within the scope of
the present invention. For instance, conductive elements 1616 and
1626 may extend through a passage formed through insulator 1628 to
communicate lumen 1650 with electrodes 1622, 1624. Lumen 1650 may
be used for aspiration as previously described.
[0086] It will be appreciated that the above-described arrangements
that provide an energy application surface area at the distal tip
of the electrosurgical instrument may be applied to an instrument
that is not capable of aspiration. Thus, insulator 1628 of
instrument 1610 may be a substantially solid element with passages
therethrough for the purpose of electrically coupling electrodes
1622 and 1624 to the power source but not for aspiration purposes.
The arrangement of the active and return electrodes may be further
modified as in FIGS. 10 and 11 to provide and energy application
surface area that, although contoured (i.e., not completely
planar), still remains at the distal end of the instrument,
substantially transverse to the longitudinal axis, without
extending along a distal portion of the side walls of the
instrument (such as in instrument 10 of FIGS. 1 and 2).
[0087] FIGS. 17A and 17B illustrate another embodiment of the
electrosurgical aspiration instrument 1710 of the present invention
in which the active electrode 1722 and the return electrode 1724
are comparably sized and located in close proximity to each other
at the distal end 1712. This arrangement of electrodes 1722 and
1724 define a true bipolar configuration. Active electrode 1722 is
a single disc shaped electrode which is centrally located at distal
end 1712 within insulator 1728. Return electrode 1724 is a ring
electrode located substantially along the same plane at the
circumferential edge of insulator 1728. The effective area size of
both electrodes are similar such that the delivered treatment
energy is equal between both electrodes. Apertures 1725 are located
within insulator 1828 and communicates with aspiration lumen 1750.
As the ablation, cutting and coagulation occur at the active
electrode 1722, the suction applied to the aspiration lumen forces
the by-products and excess fluid through apertures 1725.
[0088] FIG. 17B shows a cross-sectional view in which the active
electrode 1722 is coupled to a power supply (not shown) at the
proximal end 1714 by power conductor 1716. Return electrode 1724 is
coupled to electrically conductive shaft 1727 by extension 1736 to
complete the circuit to the power supply. Shaft 1727 is covered by
shaft insulation 1734.
[0089] FIGS. 18A-C illustrate a further alternative embodiment of
the electrosurgical aspiration instrument 1810 of the present
invention in which the active and return electrodes 1822, 1824 lie
in the same plane at the distal end 1812. The active and return
electrodes are substantially configured similarly such that the two
conductors 1816 and 1826 are electrically coupled through shaft
1827 to the distal end 1812. Electrodes 1822 and 1834 are
electrically isolated by insulator 1828. Delivery of energy is
equal to both electrodes such that an equal, bipolar effect occurs
at the surgical site. Both electrodes extend from one side of
aspiration aperture 1825 to a point across the aperture and return
to the generator. One electrode serves as an active electrode and
one electrode serves as a return electrode. It will be appreciated
that either electrode may be an active or a return since the
polarity of the power generator may be reversed. Because both
electrodes are configured across the aspiration aperture 1825,
clogging and blockage of the aperture is prevented or reduced.
[0090] FIG. 19 illustrates a perspective view of an electrosurgical
aspiration instrument 1910 according to the present invention.
Aspiration line 1952 is attached to proximal handle 1917.
Aspiration line 1952 connects to a suction device and receptacle
(not shown) which provides a negative pressure through the
instrument in order to aspirate ablation by-products through distal
tip 1912 through probe shaft 1927. A power receptacle 1914 connects
instrument 1910 to a power source (not shown). An actuator 1918
controls the amount and force of suction through the aspiration
line 1952 and is controlled by a roller. Vacuum line connector 1957
connects to the aspiration receptacle. It will be appreciated that
any device or mechanism to control the amount and force of suction
may be used to aspirate surgical material through the instrument
1910.
[0091] FIGS. 20 and 21 show two alternative embodiments of the
distal end 1912 of FIG. 19 of the present invention in which the
shaft 1927 of distal end 1912 is pre-bent. As discussed above, it
is preferable that the shaft 1927 is not flexible such that the
aspiration lumen is not pinched nor crimped thereby blocking
suction. The reduction of the suction force as discussed above may
lead to an increase in the ablation effect. FIG. 20 shows a 30
degree bend in distal end 1912 and FIG. 21 is a 90 degree bend.
While the degree of pre-bent angle is not limited to these specific
degrees, it will be appreciated that the manufacture of the
pre-bent distal end 1912 be optimized for access to a particular
body position or part for a desired surgical procedure and
corresponding ablation effect. For example, the 90 degree bend in
distal end 1912 as shown in FIG. 21 allows access to areas such as
the subacromial space under the acromium in the shoulder. This
allows for better access by a surgeon to the particular body
part.
[0092] The embodiments of the electrosurgical instrument of the
present invention that permit an aspiration function in combination
with an electrosurgical function are particularly useful for
surgical procedures requiring ablation of tissue or other body
parts. In order to perform an ablation function, the energy
supplied to the electrosurgical aspiration instrument should be in
the range of 100-500 KHz. This range may be varied depending on the
materials used to form the instrument as well as depending on the
particular application of the instrument in the surgical procedure.
The lowest frequency used typically is selected such that use of
the instrument does not interfere with other tissue nor stimulate
nerves in the area, etc. Thus, isolated treatment of the selected
tissue area is permitted. The highest frequency used typically is
limited depending on the desired results that would be achieved by
such frequency. For instance, at too high a frequency, appropriate
ablation may not be achievable and blockage of the lumen by debris
may occur.
[0093] Power may be provided by commercially available RF energy
sources. Such RF energy sources may include generators which
control the temperature of the electrosurgical instrument. Power
may also be regulated by feedback to prevent overpower and
undesired ablation or coagulation as such.
[0094] As mentioned above, the electrosurgical instrument of the
present invention may be used for any of a variety of applications
and procedures, depending on the nature of the energy supplied
thereto by the power source. It will, therefore, be appreciated
that the energy supplied to the electrosurgical instrument of the
present invention may be varied depending on the application
desired. The energy level may even be varied during use to perform
a variety of functions, such as ablation followed or accompanied by
cauterization or coagulation as necessary.
[0095] While the foregoing description and drawings represent the
preferred embodiments of the present invention, it will be
understood that various additions, modifications and substitutions
may be made therein without departing from the spirit and scope of
the present invention as defined in the accompanying claims. In
particular, it will be clear of those skilled in the art that the
present invention may be embodied in other specific forms,
structures, arrangements, proportions, and with other elements
materials, and components, without departing from the spirit or
essential characteristics thereof. The presently disclosed
embodiments are, therefore, to be considered in all respects as
illustrative and not restrictive, the scope of the invention being
indicated by the appended claims and not limited to the foregoing
descriptions.
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