U.S. patent application number 09/732848 was filed with the patent office on 2002-06-13 for methods and devices for radiofrequency electrosurgery.
Invention is credited to Chernomorsky, Ary S., Clifford, Mark J., Lee, Roberta.
Application Number | 20020072739 09/732848 |
Document ID | / |
Family ID | 24945182 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020072739 |
Kind Code |
A1 |
Lee, Roberta ; et
al. |
June 13, 2002 |
Methods and devices for radiofrequency electrosurgery
Abstract
An electrically activated surgical device includes a probe body,
an active element and a structure for selectively electrically
insulating and/or physically isolating the active element from the
patient's tissue when the device is in use. The probe body defines
an outer surface, a proximal end, a distal end and a window defined
within the outer surface near or at the distal end. The active
element is electrically connected to a power source and is
configured to selectively assume a non-deployed configuration and a
variable deployed configuration in which the active element at
least partially emerges from the window out of the probe body. The
insulating structure selectively insulates the active element from
the patient's tissue when the device is inserted therein. In
operation, a physician inserts the probe into the tissue, insulates
the active element from the tissue (either before, during or after
insertion of the probe), energizes the insulated active element
using for example, radiofrequency (RF) power from the power source,
and only then exposes the energized active element to the tissue.
By insulating the active element during the energizing thereof,
little or no current applied to the active element is dissipated in
the patient's tissue, thus decreasing the time required to energize
the active element and enabling lower and safer power levels to be
applied to the active element during the energizing thereof.
Inventors: |
Lee, Roberta; (Redwood City,
CA) ; Chernomorsky, Ary S.; (Millbrae, CA) ;
Clifford, Mark J.; (Los Altos, CA) |
Correspondence
Address: |
Alan W. Young
YOUNG LAW FIRM
4370 Alpine Road, Suite 106
Portola Valley
CA
94028
US
|
Family ID: |
24945182 |
Appl. No.: |
09/732848 |
Filed: |
December 7, 2000 |
Current U.S.
Class: |
606/41 ; 606/47;
606/49 |
Current CPC
Class: |
A61B 2018/00196
20130101; A61B 2218/008 20130101; A61B 2218/002 20130101; A61B
2018/1497 20130101; A61B 2018/0022 20130101; A61B 2018/00083
20130101; A61B 2018/00011 20130101; A61B 2018/1475 20130101; A61B
18/1482 20130101 |
Class at
Publication: |
606/41 ; 606/47;
606/49 |
International
Class: |
A61B 018/14 |
Claims
What is claimed is:
1. An electrosurgical device, comprising: a body, the body defining
an outer surface, a proximal end, a distal end and a window defined
within the outer surface; an electrically insulating layer, and an
active element, the active element being adapted to electrically
connect to a power source and configured to selectively assume a
non-deployed configuration in which the insulating layer
electrically insulates the active element from a patient's tissue
when the device is in use and a variable deployed configuration in
which the active element at least partially emerges from the window
out of the body to make contact with the patient's tissue.
2. The device of claim 1, wherein the active element includes one
of a ribbon and wire, said one of ribbon and wire being adapted to
selectively bow out of the window when transitioning from the
non-deployed configuration to the deployed configuration.
3. The device of claim 1, wherein the active element is configured
to carry out at least one of tissue ablation, dissection,
fulguration, cautery, desiccation, hyperthermia and
hypothermia.
4. The device of claim 1, wherein a thickness of the insulating
layer is selected within a range of about 0.1 mm to about 5 mm.
5. The device of claim 1, wherein the power source includes an RF
power source.
6. The device of claim 1, wherein the window is disposed one of
near the distal end of the body and at the distal end thereof.
7. The device of claim 6, wherein the active element is ring-shaped
and includes a trailing tissue collection means attached thereto
adapted to collect tissue cut by the ring-shaped active
element.
8. The device of claim 6, wherein the insulating layer includes an
electrically insulating sliding door mounted within the body, the
sliding door being configured to selectively cover at least a
portion of the window.
9. The device of claim 8, wherein the sliding door is configured to
slide between a variable first position in which at least a portion
of the active element is exposed to the patient's tissue through
the window and a second position in which the sliding door
electrically insulates the active element within the body from the
patient's tissue.
10. The device of claim 6, wherein the insulating layer includes a
layer of air and wherein the window is configured to maintain the
layer of air between the active element and the patient's tissue
when the active element is in the non-deployed configuration.
11. The device of claim 1, wherein the insulating layer includes an
electrically insulating outer sleeve configured to selectively
slide over the outer surface of the body, the outer sleeve being
configured to at least partially cover the active element to
electrically insulate the active element from the patient's tissue
and uncover the active element to expose the active element to the
patient's tissue.
12. The device of claim 1, wherein the insulating layer further
includes an electrically insulating sheath disposed around at least
a portion of the device body, the insulating sheath defining a
cutaway portion aligned with the window, the insulating sheath
defining at least one raised portion configured to prevent the
patient's tissue from prolapsing into the window when the active
element is in its non-deployed configuration.
13. The device of claim 1, wherein the insulating layer includes an
insulating sleeve disposed at least partially around the active
element, the insulating sleeve being configured to controllably
slide over the active element to selectively electrically insulate
the active element from the patient's tissue and expose the active
element thereto when the device is in use.
14. The device of claim 1, wherein the body is shaped as a
non-coring needle.
15. The device of claim 1, wherein the insulating layer includes a
layer of air and wherein the device body defines at least one
raised portion adjacent the window, the at least one raised portion
maintaining the layer of air between the active element and the
patient's tissue when the active element is in its non-deployed
state.
16. The device of claim 1, further including suction means for
controllably removing fluids from an excision site in the patient's
tissue.
17. A method of treating tissue using a probe, the probe including
an active element that is extendable out of and retractable back
into a window defined in the probe, the active element being
electrically connected to a power source, comprising the steps of:
inserting the probe into the tissue; electrically insulating the
active element from the tissue; energizing the active element using
power from the power source, and exposing the energized active
element to the tissue.
18. The method of claim 17, wherein the power source is adapted to
supply RF power to the active element.
19. The method of claim 18, wherein the insulating step includes a
step of maintaining an electrically insulating layer between the
active element and the tissue.
20. The method of claim 17, wherein the probe further includes an
electrically insulating sliding door and wherein the insulating
step includes a step of sliding the door across the window.
21. The method of claim 17, further comprising the step of inducing
hyperthermia and necrosis in the tissue exposed to the active
element.
22. The method of claim 17, further comprising the step of inducing
hypothermia and necrosis in the tissue exposed to the active
element.
23. The method of claim 17, wherein the probe further includes an
electrically insulating outer sleeve adapted to slide over an outer
surface of the probe and wherein the insulating step includes a
step of sliding the outer sleeve over the window.
24. The method of claim 17, wherein the probe further includes an
insulating sheath around at least a portion of the probe body, the
insulating sheath including at least one raised portion adjacent
the window and wherein the insulating step includes a step of
maintaining the active element retracted within the window.
25. The method of claim 17, wherein the insulating step includes a
step of maintaining the active element retracted within the
window.
26. The method of claim 17, wherein the probe further includes an
insulating sleeve adapted to slide over the active element and
wherein the insulating step includes a step of sliding the
insulating sleeve over the active element.
27. The method of claim 17, wherein the insulating step includes a
step of creating or maintaining a layer of air between the active
element and the tissue.
28. The method of claim 17, wherein the probe further includes an
inflatable balloon disposed adjacent the window, and wherein the
insulating step further includes a step of inflating the balloon to
create a layer of air between the tissue and the active
element.
29. An electrosurgical device, comprising: a device body, the body
defining a proximal end and a distal end; an active element coupled
to the body, the active element being adapted to be controllably
energized from a power source, and means for selectively
electrically insulating and exposing the active element from and to
a patient's tissue when the device is in use.
30. The device of claim 29, wherein the active element is
configured to selectively assume a non-deployed configuration in
which the active element is recessed within the body and a variable
deployed configuration in which the active element at least
partially emerges from the body.
31. The device of claim 29, wherein the active element is
configured to carry out at least one of tissue ablation,
dissection, fulguration, cautery, desiccation, hyperthermia and
hypothermia.
32. The device of claim 29, wherein the active element is
configured to be energized by an RF power source.
33. The device of claim 29, wherein the device body defines a
window disposed near the distal end of the body, the active element
being configured to selectively retract into and extend from the
window.
34. The device of claim 29, wherein a window is defined within the
body and wherein the insulating means includes an electrically
insulating sliding door mounted within the body, the sliding door
being configured to selectively cover at least a portion of the
window.
35. The device of claim 34, wherein the sliding door is configured
to slide between a variable first position in which at least a
portion of the active element is exposed through the window and a
second position in which the sliding door electrically insulates
the active element from the patient's tissue.
36. The device of claim 33 wherein the insulating means are
integral with the window and wherein the window is configured to
prevent tissue from prolapsing therein and making physical and/or
electrical contact with the active element when the active element
is in a non-deployed configuration.
37. The device of claim 29, wherein the insulating means includes
an electrically insulating outer sleeve configured to selectively
slide over the outer surface of the body, the outer sleeve being
configured to at least partially cover the active element and
electrically insulate the active element from the patient's tissue
when the device is in use and the active element is in a
non-deployed configuration.
38. The device of claim 29, wherein the insulating means includes
an electrically insulating sleeve disposed at least partially
around the active element, the insulating sleeve being configured
to controllably slide over the active element to selectively
electrically insulate the active element from the patient's tissue
and expose the active element thereto when the device is in
use.
39. The device of claim 29, wherein the insulating means are
integral with the body and define at least one raised portion, the
at least one raised portion being configured to prevent tissue from
making physical and/or electrical contact with the active element
until the active element is deployed.
40. The device of claim 29, wherein the insulating means includes
an electrically insulating sheath disposed over the body, the
insulating sheath defining at least one raised portion configured
to prevent the patient's tissue from coming into contact with the
active element until the active element is deployed.
41. The device of claim 29, wherein the active element is shaped as
a ring and wherein the insulating means are integral with the
distal end of the body, the ring-shaped active element being
configured to be recessed away from the distal end of the body
until fully energized.
42. An electrosurgical device adapted for insertion into tissue,
comprising: a device body, an RF energizable active element
disposed within the device body, and an insulating structure,
wherein at least one of the device body and the insulating
structure is configured to insulate the active element from the
tissue until the active element is sufficiently energized to be
therapeutically effective when the active element is brought into
contact with the tissue.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates primarily to the field of
electrosurgery. In particular, the present invention relates to the
field of radiofrequency (RF) electrosurgery, including RF cautery,
RF dissection, RF fulguration or coagulation, RF desiccation or any
other forms of RF-assisted electrosurgery.
[0003] 2. Description of the Related Art
[0004] Electrosurgery generally refers to the use of electrically
energized surgical devices to operate upon a patient. Common
electrosurgical devices include electrocautery devices in which a
direct current (DC) is caused to flow through a wire loop. The
resistance of the wire causes the loop to heat up, thereby enabling
the cauterization of the tissue.
[0005] More commonly, electrosurgical devices (whether monopolar or
bipolar) utilize alternating current (AC) in the range of about 200
kHz to about 3.3 MHz (hereafter "RF") that is applied to the
patient via a RF electrode. Such RF electrosurgical instruments are
typically used to dissect (cut), fulgurate (coagulate) or desiccate
(dry out) tissue by selectively varying the power and duty cycle of
the RF signal applied to the electrode of the electrosurgical
instrument. When the RF electrosurgical instrument is monopolar, a
large low impedance return (dispersive) electrode is affixed to the
patient to provide the current return path to ground. A bipolar RF
electrosurgical instrument has two electrodes, the active electrode
and the return electrode. The flow of current occurs between these
two electrodes, thus obviating the need for a large low impedance
return electrode. An insulated RF generator is typically used to
energize the RF electrode(s) of the RF electrosurgical
instrument.
[0006] The density of the current delivered to the active electrode
may be affected by the impedance (a vector quantity consisting of
the tissue's resistance and its reactance) of the tissue. The
impedance of the tissue to which the electrodes are exposed has an
important effect upon the functioning of RF electrosurgical
devices. This is because the tissue becomes an integral part of the
circuit comprising the RF generator, the active electrode, the
patient's tissue, the return electrode and back to the RF generator
to ground or a reference voltage. Therefore, a voltage controlled
or limited RF generator (generally providing power between about 10
W and 200 W) is generally used, so that when the impedance of
tissue rises, the current delivered to the active electrode safely
decreases. The density and impedance of tissue affects the manner
in which it is affected by the active electrode. Tissues with
higher salt content and body fluids such as blood have a high
conductance and therefore, lower impedance. Fatty tissues have a
lower fluid content and generally exhibit relatively higher
impedance than leaner tissues. Thus, for a given voltage, fatty
tissue will dissipate less current than leaner tissue. Highly
vascularized tissues, on the other hand, have very low impedance
and tend to conduct current more efficiently than less vascularized
tissues. Therefore, to achieve the same tissue effect, current must
be applied to a RF electrode in contact with highly vascularized
tissue for a longer period of time than would be the case if the RF
electrode were in contact with comparatively less vascularized
tissue. Alternatively, the initial power applied to the RF
electrode may need to be momentarily increased to achieve the same
tissue effect in a fixed period of time.
[0007] FIGS. 1-3 show a RF excisional device 100 that includes a
probe 102, the distal end 108 of which includes a conductive ribbon
or wire loop 106 configured to bow out of and back into a window
104 defined within the probe 102. The loop 106 is connected to a RF
power supply (not shown). The loop 106 is energized with RF energy
and the probe 102 is rotated as shown at 112 with the loop 106 in
an extended or deployed configuration, as shown in FIG. 3. As the
probe 102 is rotated, a volume of revolution of tissue is cut by
the RF-energized loop 106.
[0008] However, when the loop 106 is in contact with the tissue to
be cut, the physician often must wait a relatively long period of
time (several seconds or longer) between initial application of the
RF power to the loop 106 and the time at which the current density
within the loop 106 is high enough to cut (vaporize) the tissue.
This is because the relatively low impedance of the interface
between the loop 106 and the patient's tissue shown at 114 in FIG.
5 dissipates a substantial amount of the current delivered to the
loop 106. Highly vascularized tissue may also increase the current
conduction (symbolized by the arrows emanating from the loop 106 in
FIG. 5) away from the loop 106 and further delay the time at which
the RF loop 106 is able to cut through the tissue 114. Indeed,
until the tissue 114 chars and the impedance thereof increases, the
current density within the loop 106 may not quickly reach that
level at which the energized loop 106 is therapeutically
effective.
[0009] One solution to this problem is to initially increase or
surge the power delivered to the loop 106 to decrease the time
required for the current density therein to reach the desired
level. However, this is a less than optimal solution, as such an
initial power surge may cause pain, excessive charring of the
tissue 114 at the initial cut site, and may present a safety risk
to the patient, who is better served by maintaining power levels as
low as practicable to achieve the objective of the procedure. Such
initial power surges, moreover, require specialized RF generators
that are configured to deliver such surges safely and on
demand.
[0010] What are needed, therefore, are improved methods and RF
electrosurgical devices that do not suffer from the aforementioned
disadvantages. More particularly, what are needed are RF
electrosurgical devices that energize quickly, cut more efficiently
and less painfully, reduce tissue charring at the initial cut site,
and do not require an initial power surge from a specialized RF
generator.
SUMMARY OF THE INVENTION
[0011] It is, therefore, an object of the present invention to
provide methods and RF electrosurgical instruments that do not
suffer from the aforementioned disadvantages. It is also an object
of the present invention to provide RF electrosurgical instruments
that energize quickly, are safer, cut more efficiently and less
painfully, reduce tissue charring at the initial cut site and do
not require an initial power surge from a specialized RF
generator.
[0012] In accordance with the above-described objects and those
that will be mentioned and will become apparent below, an
electrosurgical device according to an embodiment of the present
invention, includes a body, the body defining an outer surface, a
proximal end, a distal end and a window defined within the outer
surface; an electrically insulating layer and an active element,
the active element being adapted to electrically connect to a power
source and configured to selectively assume a non-deployed
configuration in which the insulating layer electrically insulates
the active element from a patient's tissue when the device is in
use and a variable deployed configuration in which the active
element at least partially emerges from the window out of the body
to make contact with the patient's tissue.
[0013] The active element may include one of a ribbon and wire,
said one of ribbon and wire being adapted to selectively bow out of
the window when transitioning from the non-deployed configuration
to the deployed configuration. A tissue collection means may be
attached thereto or trail behind the active element, as disclosed
in co-pending and commonly assigned U.S. patent application Ser.
No. 09/565,611 filed on May 4, 2000 and/or commonly assigned U.S.
Pat. No. 6,022,362 filed on Sept. 3, 1998, the disclosure of each
being incorporated herein by reference in its entirety.
[0014] The active element may be configured to carry tissue
ablation, dissection, fulguration, cautery, desiccation,
hyperthermia or hypothermia, for example. The thickness of the
insulating layer may be selected within a range of about 0.1 mm to
about 5 mm, for example. The power source may include a RF power
source. The window may be disposed near the distal end of the body
or at the distal end thereof. The active element may be ring-shaped
and may include a trailing tissue collection means attached thereto
adapted to collect tissue cut by the ring-shaped active element.
The insulating layer may include an electrically insulating sliding
door mounted within the body, the sliding door being configured to
selectively cover at least a portion of the window. The sliding
door may be configured to slide between a variable first position
in which at least a portion of the active element is exposed to the
patient's tissue through the window and a second position in which
the sliding door electrically insulates the active element within
the body from the patient's tissue. The insulating layer may
include a layer of air and the window may be configured to maintain
the layer in the non-deployed configuration. The insulating layer
may include an electrically insulating outer sleeve configured to
selectively slide over the outer surface of the body, the outer
sleeve being configured to at least partially cover the active
element to electrically insulate the active element from the
patient's tissue and uncover the active element to expose the
active element to the patient's tissue. The insulating layer
further may include an electrically insulating sheath disposed
around at least a portion of the device body, the insulating sheath
defining a cutaway portion aligned with the window and defining one
or more raised portions configured to prevent the patient's tissue
from prolapsing into the window when the active element is in its
non-deployed configuration. The insulating layer may include an
insulating sleeve disposed at least partially around the active
element, the insulating sleeve being configured to controllably
slide over the active element to selectively electrically insulate
the active element from the patient's tissue and expose the active
element thereto when the device is in use. The body may be shaped
as a non-coring needle. The insulating layer may include a layer of
air and the device body may define one or more raised portions
adjacent the window, the raised portion(s) maintaining the layer of
air between the active element and the patient's tissue when the
active element is in its non-deployed state. Suction means may be
included within the body for controllably removing fluids from the
operative site within the patient's tissue.
[0015] The present invention may also be viewed as a method of
treating tissue using a probe, the probe including an active
element that may be extendable out of and retractable back into a
window defined in the probe, the active element being electrically
connected to a power source, comprising the steps of: inserting the
probe into the tissue; electrically insulating the active element
from the tissue; energizing the active element using power from the
power source, and exposing the energized active element to the
tissue.
[0016] The power source may be adapted to supply RF power to the
active element. The insulating step may include a step of
maintaining an electrically insulating layer between the active
element and the tissue. The probe further may include an
electrically insulating sliding door and the insulating step may
include a step of sliding the door across the window. The method
may further comprise the step of inducing hyperthermia or
hypothermia and necrosis in the tissue exposed to the active
element. The probe further may include an electrically insulating
outer sleeve adapted to slide over an outer surface of the probe
and the insulating step may include a step of sliding the outer
sleeve over the window. The probe further may include an insulating
sheath around at least a portion of the probe body, the insulating
sheath including at least one raised portion adjacent the window
and the insulating step may include a step of maintaining the
active element retracted within the window. The insulating step may
include a step of maintaining the active element retracted within
the window. The probe further may include an insulating sleeve
adapted to slide over the active element and the insulating step
may include a step of sliding the insulating sleeve over the active
element. The insulating step may include a step of creating or
maintaining a layer of air between the active element and the
tissue. The probe further may include an inflatable balloon
disposed adjacent the window, and the insulating step further may
include a step of inflating the balloon to create a layer of air
between the tissue and the active element.
[0017] The present invention is also an electrosurgical device,
comprising a device body, the body defining a proximal end and a
distal end; an active element coupled to the body, the active
element being adapted to be controllably energized from a power
source; and means for selectively electrically insulating and
exposing the active element from and to a patient's tissue when the
device is in use.
[0018] The active element may be configured to selectively assume a
non-deployed configuration in which the active element is recessed
within the body and a variable deployed configuration in which the
active element at least partially emerges from the body. The active
element may be configured to carry out tissue ablation, dissection,
fulguration, cautery, desiccation, hyperthermia and/or hypothermia,
for example. The active element may be configured to be energized
by a RF power source, for example. The device body may define a
window disposed near the distal end of the body, and the active
element may be configured to selectively retract into and extend
from the window. A window may be defined within the body and the
insulating means may include an electrically insulating sliding
door mounted within the body, the sliding door being configured to
selectively cover at least a portion of the window. The sliding
door may be configured to slide between a variable first position
in which at least a portion of the active element is exposed
through the window and a second position in which the sliding door
electrically insulates the active element from the patient's
tissue. The insulating means may be integral with the window and
the window may be configured to prevent tissue from prolapsing
therein and making physical and/or electrical contact with the
active element when the active element is in a non-deployed
configuration. The insulating means may include an electrically
insulating outer sleeve configured to selectively slide over the
outer surface of the body, the outer sleeve being configured to at
least partially cover the active element and electrically insulate
the active element from the patient's tissue when the device is in
use and the active element is in a non-deployed configuration. The
insulating means may include an electrically insulating sleeve
disposed at least partially around the active element, the
insulating sleeve being configured to controllably slide over the
active element to selectively electrically insulate the active
element from the patient's tissue and expose the active element
thereto when the device is in use. The insulating means may be
integral with the body and may define one or more raised portions,
the raised portion(s) being configured to prevent tissue from
making physical and/or electrical contact with the active element
until the active element is deployed. The insulating means may
include an electrically insulating sheath disposed over the body,
the insulating sheath defining at least one raised portion
configured to prevent the patient's tissue from coming into contact
with the active element until the active element is deployed. The
active element may be shaped as a ring and the insulating means may
be integral with the distal end of the body, the ring-shaped active
element being configured to be recessed away from the distal end of
the body until fully energized.
[0019] The present invention is also an electrosurgical device
adapted for insertion into tissue, comprising: a device body; a RF
energizable active element disposed within the device body, and an
insulating structure. The device body and/or the insulating
structure may be configured to insulate the active element from the
tissue until the active element is sufficiently energized to be
therapeutically effective when the active element is brought into
contact with the tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a top view of the distal end of an expandable loop
excisional device.
[0021] FIG. 2 is a side view of the distal end of the excisional
device of FIG. 1, in which the loop is in its non-extended
(non-deployed) configuration.
[0022] FIG. 3 is a side view of the distal end of the excisional
device of FIG. 1, in which the loop is in its extended (deployed)
configuration.
[0023] FIG. 4 is a cross-sectional view of the excisional device of
FIG. 2, taken along cross-sectional lines AA'.
[0024] FIG. 5 shows the excisional device of FIG. 4 in which the
loop is in contact with tissue, to illustrate the current
dissipation occurring at the loop-tissue interface.
[0025] FIG. 6 shows an embodiment of a RF electrosurgical device,
according to an embodiment of the present invention.
[0026] FIG. 7 shows the distal end of the RF electrosurgical device
of FIG. 6, in which the active element thereof is in its
non-extended (non-deployed) configuration.
[0027] FIG. 8 shows the distal end of the RF electrosurgical device
of FIG. 7, in which the active element thereof is in its extended
(deployed) configuration.
[0028] FIG. 9 is a cross-sectional view of the excisional device of
FIG. 7, taken along cross-sectional lines BB'.
[0029] FIG. 10 shows the excisional device of FIG. 9 and
illustrates the absence of active element-tissue interface when the
RF electrosurgical device of the present invention is initially
inserted in tissue and RF power applied to the active element.
[0030] FIG. 11 shows another embodiment of a RF electrosurgical
device, according to the present invention.
[0031] FIG. 12 shows the distal end of the RF electrosurgical
device of FIG. 11, in which the active element thereof is in a
non-extended (non-deployed configuration).
[0032] FIG. 13A shows the distal end of the RF electrosurgical
device of FIG. 11, in which the active element thereof is in a
first illustrative extended (deployed configuration).
[0033] FIG. 13B shows the distal end of the RF electrosurgical
device of FIG. 11, in which the active element thereof is in a
second illustrative extended (deployed configuration).
[0034] FIG. 14 is a cross-sectional view of the excisional device
of FIG. 12, taken along cross-sectional lines CC'. FIG. 15 shows
the excisional device of FIG. 14 and illustrates the absence of
active element-tissue interface when the RF electrosurgical device
of the present invention is initially inserted in tissue and RF
power is applied to the active element.
[0035] FIG. 16 is a top view of another embodiment of an
electrosurgical device according to the present invention.
[0036] FIG. 17 shows a side view of the distal end of the
electrosurgical device of FIG. 16, in which the active element
thereof is in its non-deployed configuration.
[0037] FIG. 18 shows the electrosurgical device of FIG. 17, in
which the active element thereof is in its deployed
configuration.
[0038] FIG. 19 shows a side view of another embodiment of an
electrosurgical device according to the present invention, in which
the active element thereof is in its non-deployed
configuration.
[0039] FIG. 20 shows the electrosurgical device of FIG. 19, in
which the active element thereof is in its deployed
configuration.
[0040] FIG. 21 is a top view of the distal end of an
electrosurgical device according to a still further embodiment of
the present invention.
[0041] FIG. 22A is a side view of the device of FIG. 21, in which
the inflatable balloon(s) thereof has (have) been inflated to
create an insulating layer between the active element and the
patient's tissue.
[0042] FIG. 22B is a front view of the device of FIG. 22A, in which
the balloons are in their inflated configuration.
[0043] FIG. 23 is a side view of the device of FIG. 21, after
deflation of the balloon(s) and deployment of the active
element.
[0044] FIG. 24 shows a top view of the distal end of an
electrosurgical device according to another embodiment of the
present invention.
[0045] FIG. 25 shows a side view of the device of FIG. 24.
[0046] FIG. 26 shows the device of FIG. 25, after the outer sleeve
thereof has been slid away from the window from which the active
element is deployed.
[0047] FIG. 27 is a flowchart of a method for carrying out an
electrosurgical procedure according to an embodiment of the present
invention.
[0048] FIG. 28 is a top view of an electrosurgical device,
according to another embodiment of the present invention.
[0049] FIG. 29 is a side view of the distal portion of the device
of FIG. 28, showing the active element thereof in its non-extended
and sheathed state.
[0050] FIG. 30 is a side view of the distal portion of the device
of claim 28, showing the active element thereof in its extended and
unsheathed state.
[0051] FIG. 31 is a cross-sectional view of the electrosurgical
device of FIG. 29, taken along cross-sectional lines DD'.
[0052] FIG. 32 is a top view of an electrosurgical device,
according to another embodiment of the present invention.
[0053] FIG. 33 is a side view of the distal portion of the device
of FIG. 32.
[0054] FIG. 34 is a side view of the distal portion of the device
of FIG. 32, in which the active element is in its extended
state.
[0055] FIG. 35 is a cross-sectional view of the electrosurgical
device of FIG. 33, taken along cross-sectional lines EE'.
[0056] FIG. 36 shows a cross-sectional view of another embodiment
of the electrosurgical device of FIG. 33, taken along cross
sectional lines EE'
[0057] FIG. 37 shows another electrosurgical device, according to
yet another embodiment of the present invention.
[0058] FIG. 38 is a perspective side view of the distal portion of
the electrosurgical device of FIG. 37, in which the electrosurgical
ring is in its non-extended state.
[0059] FIG. 39 is a perspective side view of the distal portion of
the electrosurgical device of FIG. 37, in which the electrosurgical
ring is in its extended state.
DESCRIPTION OF THE INVENTION
[0060] FIGS. 6-10 show an embodiment of a RF electrosurgical device
200, according to the present invention. As shown therein, the
device 200 includes a probe body 202, the probe body 202 defining
an outer surface, a proximal end 230, a distal end 208 and a window
204 (shown in dashed lines in FIGS. 7 and 8) defined within the
outer surface near the distal end 208. The probe 200 includes an
active element 206. The active element 206 may include, for example
one or more wires and/or loops, or any other therapeutically
effective RF element effective to cut, dissect, fulgurate and/or
desiccate tissue (for example) using RF power. The active element
206 may be electrically connected to a power source, such as the RF
power source 240. A distal RF element 210 may also be mounted to
the distal end 208 of the probe body 202, to facilitate penetration
of the probe 200 into the patient's tissue. The distal RF element
210 may also be independently electrically connected to the RF
power source 240. According to the present invention, the active
element 206 may be configured to selectively assume a non-deployed
configuration (FIG. 7) and a variable deployed configuration (FIG.
8). In the variable deployed configuration (FIG. 8), the active
element 206 at least partially emerges from the window 204 out of
the probe body 202. The deployment of the active element 206 may be
controlled by the physician by means of an actuator 236, such as
the thumb wheel shown in FIG. 6 or other actuation means. By
turning the actuator 236 with his or her thumb, the physician
causes the active element 206 to slide within a guide 326 defined
within the probe 202. As the distal end of the active element 206
is attached to the distal end 208 of the probe 200, the active
element 206 bows out of the window 204, the degree of bowing and
deployment out of the window 204 being controlled by the actuator
236.
[0061] In the non-deployed configuration, the active element 206 is
recessed within the probe body 202 to define an insulating layer
212 (a layer of air, for example) with respect to the outer surface
of the probe body 202. The recessed active element 206 and/or the
presence of the insulating layer 212 enables the active element 206
to be energized without contacting the patient's tissue. Indeed, by
avoiding contact with the patient's tissue during the energizing of
the active element 206, the current delivered to the active element
206 is not dissipated by the patient's tissue that would otherwise
be in contact therewith but for the presence of the insulating
layer 212. According to the present invention, after the active
element 206 is energized, the active element 206 may be deployed to
(for example) cut, ablate or coagulate (depending upon the
application) the patient's tissue without the physician having to
wait for the tissue impedance to rise sufficiently (while the
patient's tissue heats up and/or chars) to enable the current
density within the active element 206 to reach the desired level
for the procedure to be carried out. FIGS. 9 and 10 show a
cross-sectional view of the probe 200, taken along the
cross-sectional lines BB'of FIG. 7. As shown therein, to
electrically insulate the active element 206 from the patient's
tissue (reference 214 in FIG. 10), the window 204 defined within
the probe body 202 may be shaped and/or dimensioned so as to
prevent the tissue 214 through which the probe 200 is inserted from
prolapsing therein. As shown, the window 204 is configured to
define an electrically insulating layer 212 between the active
element 206 and the patient's tissue 214 when the active element
206 is in its non-deployed (retracted) configuration. Toward that
end, the window 204 may define a steep aspect ratio, in which the
depth of the window 204 is greater than its width.
[0062] FIGS. 11-15 show a probe 300 according to another embodiment
of the present invention. Reference numerals that are identical to
those shown in FIGS. 6-10 denote identical structures. For the sake
of brevity, the description of those identical structures will not
be explicitly repeated here. In FIGS. 11-15, the insulating layer
that electrically insulates the active element 206 from the
patient's tissue 214 includes a sliding door 216 disposed within
the probe body 202. The sliding door 216 may be made of an
electrical insulator or other substantially non-conductive material
or materials. The sliding door 216 is configured to selectively
cover at least a portion of the window 204 to electrically insulate
the active element 206 of the device 300 from the patient's tissue
214 until the active element 206 is fully energized and/or until
the physician chooses to expose the active element 206 to the
patient's tissue 214. The physician, according to the present
invention, may cause the sliding door 216 to slide and expose the
active element 206 by means of a sliding door actuator such as a
manual thumb wheel, as shown at 356. It is understood that other
means of acting upon the sliding door 216 and/or active element 206
may be employed, as the present invention is not limited to thumb
wheel actuators, as shown at 356 and 236. According to the present
invention, the sliding door 216 is configured to slide between a
variable first position in which at least a portion of the active
element is exposed through the window (as shown in FIGS. 13A and
13B) and a second position (shown in FIGS. 11, 12, 14 and 15) in
which the sliding door 216 insulates the active element 206 within
the probe body 202. As shown in FIGS. 13A and 13B, the sliding door
216 may be caused to expose a selectable portion of the active
element 206 to the patient's tissue 214. In so doing, the sliding
door 216 may affect the shape of the deployed active element: if
the sliding door 216 is fully or near fully retracted as shown in
FIG. 13A, a greater portion of the active element 206 may emerge
from the window 204 than is the case wherein the sliding door 216
is only partially retracted and only exposes a portion of the
window 204, as shown in FIG. 13B. This may enable the physician to
control the extent of deployment and the shape of the extended
active element 206. FIGS. 14 and 15 show the sliding door 216 as it
covers the window 204, thereby electrically insulating the active
element 206 from the patient's tissue 214. The sliding door 216 may
be guided within the probe body 202 by means of, for example,
internal guides or rails 218. Using this configuration, the
physician may apply RF power to the active element 206 and begin
the intended RF procedure (cutting, ablating, coagulating, etc.)
sooner than would otherwise be the case if the de-energized active
element were energized while in contact with the patient's tissue
214. The layer of air 213 between the active element 206 and the
sliding door 216 may be reduced or eliminated altogether, as the
sliding door 216 electrically insulates and physically isolates the
active element 206 from the patient's tissue 214. The sliding door
216, for that purpose, is preferably formed of non-conductive
material, such as a non-conductive plastic or ceramic, for
example.
[0063] FIGS. 16-18 show another embodiment of the present
invention. As shown therein, the electrosurgical device 400
includes a proximal end 260, a distal end 208, a probe body 202, an
active element actuator 236 and a sliding door actuator 356, as
described above. The distal tip of the probe body defines an
opening 290 that is aligned with an internal lumen 282 defined
within the probe body 202. The exemplary active element 218 shown
in FIGS. 16-18 includes an elongated conductive stem that is
distally terminated by a conductive bulb. However, any electrically
active element may be used in conjunction with or in place of the
active element depicted in FIGS. 16-18. The active element 218 may
be electrically coupled to the RF power source 240. The bulb may be
used, for example, to induce hyperthermia and/or necrosis in the
tissue 214 with which it comes into contact. In that case, the duty
cycle of the RF current applied to the active element 218 may be
adjusted to be, for example, 50%-25%, so as to induce substantial
heating in the tissue 214 in contact with the active element 218.
In this embodiment, the insulating layer separating the active
element 218 from the patient's tissue 214 when the active element
206 is in its non-deployed configuration may include a sliding and
electrically insulating door 220 mounted within the probe body 202.
The sliding door 220 may be configured to slide axially in the
distal and proximal directions (away from and toward the physician,
respectively, when the device 400 is in use) when the sliding door
actuator 356 is actuated. The distal end of the sliding door 220
may be advantageously configured to cover (see FIG. 17) the opening
290 during insertion of the device 400 into the patient's tissue
214 and during the energizing of the active element 218. After the
device 400 has been inserted up to the targeted site within the
patient's tissue 214 and the active element 218 has been energized,
the physician may actuate the sliding door actuator 356 to retract
the sliding door 220 away from the opening 290, in the proximal
direction 294. Thereafter, the energized active element 218 may be
advanced in the distal direction 296 into the target area of the
patient's tissue 214 to begin treatment thereof, as shown in FIG.
18. Alternatively, the sliding door 220 may be retracted before the
active element 218 is energized. Thereafter, the active element 218
may be energized without dissipating current into the surrounding
tissue 214, as the active element 218 is still recessed and
electrically insulated from the patient's tissue by an air layer
215. The shape and/or size of the opening 290 and/or the thickness
of the air layer 215 may also prevent the patient's tissue 214 from
prolapsing into the opening 290, thereby further insulating the
active element 218. As shown in FIGS. 16 and 17, the active element
218 is fully insulated from the patient's tissue 214 by the sliding
door 220 until the active element 218 is appropriately energized,
thereby preventing any disadvantageous dissipation of RF current
into the tissue 214 upon the application of RF current to the
active element 218.
[0064] FIGS. 19-20 show a still further embodiment of the present
invention. As shown therein, the electrosurgical device 500
includes a probe body 202 defining a proximal end 230, a distal end
208 and an internal lumen 217. The proximal end 230 includes an
active element actuator 236, as described above. An active element
218 is configured to slide within the internal lumen 217, as
controlled by the active element actuator 236. Most any RF active
element may be used within the electrosurgical device 500. For
simplicity's sake, however, the stem and bulb active element 218 of
FIGS. 16-18 is again used here, it being understood that this
embodiment is not limited thereby. As shown in FIGS. 19-20, the
distal end 208 of the probe body 202 may be shaped as a non-coring
needle. As shown in FIG. 19, the active element 218 may be recessed
within the internal lumen 217 of the probe body to define an
electrically insulating layer 219. The layer 219 may also
physically isolate the active element 218 from the patient's tissue
when the active element is in its non-deployed state, as shown in
FIG. 19. When the device 500 is properly positioned within the
patient (as verified, for example, through the use of ultrasound)
and the active element 218 energized, the active element actuator
236 may be used to advance the energized active element 218 in the
distal direction 296 until the active element 218 emerges from the
distal opening 292 and extends to the desired length, as shown in
FIG. 20. The insulating layer 219 (FIG. 19) between the active
element 218 and the opening 294 defined in the distal end of the
probe body 202 (and/or the tissue 214) prevents any of the RF
current applied to the active element 218 from dissipating into the
patient's tissue 214 during the energizing of the active element
218.
[0065] Some or all of the through holes 938 may be utilized for the
delivery of a fluid to the patient during the procedure, such as
antibiotic agents, analgesic agents or most any pharmaceutical
agent. Such agents may be administered to the patient from the port
942. Alternatively, the port 942 may be coupled to suction and some
or all of the through holes 938 may be utilized to suction out the
operative site of smoke, blood or other bodily fluids during or
after the operative procedure. Alternatively still, more than one
port 942 may be provided in the proximal portion 902 and more than
one internal lumen 940 may be defined along the length of the probe
500. The additional lumen may be in fluid communication with
selected through holes 938. By this structure, both delivery of a
pharmaceutical agent and suctioning may be provided within a single
probe 500. It is to be understood that any of the devices according
to the present invention may incorporate all or a portion of the
structures referenced by 938, 940 and 942 or like structures to
provide suctioning and/or fluid delivery functionality.
[0066] FIGS. 21-23 shows the distal portion of a still further
embodiment of the present invention. As shown therein, the device
600 defines a distal end 208, a window 204 and an active element
206, as described above. The device 600 also includes one or more
inflatable balloons 602. As best shown in FIG. 21, at least one
such balloon 602 may advantageously be disposed in close proximity
to and may be co-extensive with the window 204 from which the
active element 206 emerges and deploys. FIG. 22A shows the device
600 in a configuration wherein the active element 206 is in its
non-deployed configuration and the balloons 602 are in their
inflated configuration. For example, the balloons 602 may be
inflated with CO.sub.2 (for example) from a CO.sub.2 reservoir (not
shown) located within or without the device 600. FIG. 22B shows a
front view of the device of FIG. 22A and illustrates the insulating
layer 212 between the active element 206 and the tissue 214 created
by the inflation of the balloons 602. Finally, FIG. 23 shows a side
view of the device 600 in a configuration wherein the active
element 206 is deployed and the balloons 602 deflated, rendering
them (preferably) flush or substantially flush with the outer
surface of the device 600. In operation, the device 600 may be
advanced through the patient's tissue 214 until the target area is
reached. The balloon or balloons 602 may then be inflated, thereby
creating the insulating layer 212 between the active element 206
and the tissue 214. The active element 206 may then be energized
with RF current from a RF power supply, such as shown at 240 in
FIG. 16, for example. After energizing the active element 206, the
balloon 602 or balloons 602 may be deflated and the active element
deployed, as described above. Once again, initially electrically
insulating the active element 206 from the tissue 214
advantageously prevents current from dissipating into the tissue
214 during the energizing of the active element 206. Thereafter,
the active element 206 may be brought into contact with the
patient's tissue 214 when the active element 206 has been energized
to a therapeutically effective level.
[0067] FIGS. 24-26 show the distal portion of a still further
embodiment of the present invention. As shown therein, the
electrosurgical device 700 includes a probe body 202, a window 204
defined within the probe body 202 near the distal end 208 thereof,
and an active element 206 within the window 204, as previously
described. To electrically insulate the active element 206 during
the energizing thereof using a RF power source (such as shown at
240 in FIG. 16), an electrically insulating outer sleeve 702 is
fitted over the probe body 202. The outer sleeve 702 is configured
to slide over and/or against the outer surface of the probe body
202 in the proximal and axial directions. Upon energizing the
active element 206, the outer sleeve 702 may advantageously be
maintained in a position wherein it prevents tissue 214 from coming
into contact with the active element 206. After the active element
206 is energized, the physician may retract the outer sleeve 702 by
sliding it in the proximal direction 294. By fully retracting the
outer sleeve 702, the physician may expose the entire active
element 206 to the tissue 214. However, by only partially
retracting the outer sleeve 702, as shown at 702A, the physician
may advantageously change the extent of deployment and/or shape of
the active element, as shown at 206A.
[0068] It should also be noted that the active element in FIGS.
6-26 may also include a device to cause hypothermia and subsequent
necrosis in the patient's tissue; i.e., to freeze the patient's
tissue in contact with the active element. Indeed, by energizing
such an active device while it is electrically insulated and/or
physically isolated from the patient's tissue 214, the temperature
of the active element will drop to the intended low temperature
faster than if the active element were initially in contact with
the patient's tissue 214, especially if the tissue is highly
vascular (and thus able to transport heat efficiently).
[0069] FIG. 27 is a flowchart of a method of carrying out an
electrosurgical procedure, according to the present invention. Step
SI calls for the insertion of a RF electrosurgical device, such as
shown in FIGS. 6-26, into the patient's tissue. Advantageously,
ultrasound (or any other radiological) guidance may be employed to
guide the device to the targeted site within the patient's tissue.
Step S2 calls for electrically insulating (and/or physically
isolating) the active element (such as shown at 206, 218) of the RF
device from the surrounding tissue. The insulating step S2 may be
carried out either before, during or after step S1, but should be
carried out before step S3 that is, before energizing the active
element. Insulating and/or electrically isolating the active
element may entail ensuring the presence of an insulating layer
(preferably about 0.1 mm to about 5 mm in thickness) by maintaining
the active element recessed within the probe body, in its
retracted, non-deployed configuration and/or sliding a sliding door
(216, 220) over the active element, inflating a balloon or balloons
602 and/or maintaining an outer sleeve 702 over the active element.
Alternatively, any means of creating an insulating layer 212 and/or
insulating the active element from the surrounding tissue during
the energizing thereof may be employed within the scope of the
present invention. Step S4 calls for exposing at least a portion of
the energized active element to the patient's tissue and step S5
calls for carrying out the intended procedure, such as cutting,
ablation, coagulation, etc.
[0070] FIGS. 28-31 represent different views of an electrosurgical
device 800, according to another embodiment of the present
invention. Considering now FIGS. 28-31 collectively, the device 800
includes a proximal end 260, a distal end 208 and may include a
distal RF element 210, as described above. The device 800 includes
an active element 206, which may include one or more wires and/or
loops, or any other therapeutically effective RF element effective
to cut, dissect, fulgurate, induce hyper or hypothermia (from a
different power source) and/or to desiccate tissue using RF power.
The active element 206 may be electrically coupled to a power
source, such as the RF power source 240. The embodiment illustrated
in FIGS. 28-31 is configured to selectively electrically insulate
and/or physically isolate the active element 206 from the patient's
tissue 214. Indeed, the active element 206 may be selectively
insulated and/or isolated from the patient's tissue 214 by means of
an insulating sleeve 802 that is configured to at least partially
surround and at least partially cover the active element 206, as
most clearly shown in the cross-sectional view of FIG. 31. The
insulating sleeve 802 is further configured to slide over the
active element 206 and to loosely cover the element 206, as shown
in FIG. 29. When the active element 206 is fully energized, the
sleeve 802 may be retracted in the proximal direction (toward the
physician) using an appropriate actuator such as the insulating
sleeve actuator 357 for example, thereby exposing the active
element 206 to the patient's tissue and enabling deployment of the
active element 206, as shown in FIG. 30. The insulating and
retractable sleeve 802 may include or be formed of a flexible
material, such as a silicone elastomer (such as polydimethyl
siloxane, for example). During the procedure, the active element
206 may be retracted within the window 204 defined within the probe
body and the insulating sleeve 802 advanced in the distal direction
(i.e., toward the distal end 208). This may enable the operator to
remove any char that may have adhered to the active element 206
without, however, removing the probe 800 from the patient.
[0071] FIGS. 32-36 show a still further embodiment of the present
invention, in which the active element 206 of the electrosurgical
device 900 is initially electrically insulated from the patient's
tissue 214 not by an insulating sleeve, but by an external sheath
902 (FIGS. 32-35) or by the configuration or topology of the probe
body 200 (FIG. 36). Considering FIGS. 32-35 collectively, this
embodiment of the electrosurgical device 900 of the present
invention includes a probe body 202 defining a proximal end 260 and
a distal end 208. The device 900 includes an active element 206,
which may include one or more wires and/or loops, or any other
therapeutically effective element effective to cut, dissect,
fulgurate, or induce hyper or hypothermia. The active element 206
may be electrically coupled to a power source, such as the RF power
source 240. The device 900 may also include a distal RF element
210. As shown, the device 900 may also include an insulating sheath
902 disposed over at least a portion of the probe body 202.
According to the present invention, the sheath 902 may include a
cutaway portion 910 that may be aligned with and expose the
underlying window 204 defined within the probe body 202. As shown
in FIG. 33, when the active element 206 is in its retracted
position, the insulating sheath 902 electrically insulates the
active element 206 from the patient's tissue 214, whereas the
sheath 902 does not interfere with the active element 206 when the
active element 206 is in its extended configuration, as shown in
FIG. 34. Suction may be advantageously employed here to clear the
operative site from electrically conductive bodily fluids and/or
smoke. As shown most clearly in the cross-sectional view of FIG.
35, the sheath 902 may have a generally circular cross section, and
may include one or more raised portions 906 adjacent to the window
204 and substantially aligned therewith. The raised portion(s) 906
enable the active element 206, in its retracted position, to be
electrically insulated from the patient's tissue 214 by an
insulating layer 904 measuring about 0.1 mm to about 5 mm in
thickness, for example. In this manner, the active element 206 may
be fully energized by the RF power source 240 before being brought
into contact with the patient's tissue, with the accompanying
advantages discussed above. The sheath 902 may cover all or only a
portion of the probe body 202.
[0072] FIG. 36 shows another embodiment of the present invention,
wherein the probe body alone is shaped so as to insulate the active
element 206 from the patient's tissue 214 until the active element
206 is fully energized. As shown therein, the probe body 202 may
include one or more locally raised portions 907 adjacent to the
window 204 from which the active element 206 extends. The raised
portion(s) 907 (raised about 0.5 mm to about 5 mm away from the
outer surface of the probe body, for example) may be defined along
the long sides of the window 204 or around the entire perimeter
thereof. The raised portion(s) 907 need not be continuous, as long
as they serve to effectively electrically insulate the tissue 214
from the active element 206 until the active element 206 is fully
energized. As shown in FIG. 36, the tissue 214 is separated from
the non-extended active element 206 by the insulating (air) layer
904 by the raised portions 907 of the probe body 202 which prevent
the tissue 214 from prolapsing into the window 204 and coming into
contact with the active element 206 until the physician chooses to
extend the active element 206 and begin cutting the patient's
tissue 214.
[0073] Any geometry of the sheath 902 and/or probe body 202 and/or
active element that forms an insulating layer between the active
element and the patient's tissue when the active element is in its
non-deployed state falls into the scope of the present invention.
Likewise, any structure that prevents the tissue 214 from
prolapsing into the window 204 or that generally prevents the
active element 206 from coming into contact with the tissue until
the active element 206 is fully energized also falls within the
scope of the present invention.
[0074] The present invention, moreover, is not limited to any
particular active element. Indeed, although the embodiments of the
present invention are herein illustrated with an extendible loop
active element, the present invention is not so limited. An
important aspect of the present invention is the electrical
insulation and/or physical isolation of the active element of an
electrosurgical device from the patient's tissue until the active
element is fully energized. This aspect is again illustrated in
FIGS. 37-39, in which the active element is shown as having a ring
shape and the probe body little more than a hollow cannula. The
electrosurgical device 1000 shown in FIGS. 37-39 includes a probe
body 1002 that defines a proximal end 260 and a distal end 1012. An
active element actuator 236 is configured to extend and retract a
ring-shaped RF element 1006 from and back into the distal end 1012
of the probe body 1002. The ring-shaped active element 1006 is
electrically coupled to the RF power source 240 and mechanically
coupled to the actuator 236 by means of rod 1004 or by other means
known to those of skill in this art. FIG. 38 shows the distal end
1012 of the probe body 1002 and the ring-shaped active element 1006
in its retracted position. In accordance with the present
invention, the active element 1006 is electrically insulated from
the patient's tissue (not shown) by virtue of its recessed position
(recessed by a distance of about 0.1 mm to about 5 mm, for example)
within the probe body 1002. Suction may be employed to maintain the
recess clear of bodily fluids. This enables the physician to insure
that the active element 1006 is fully energized before the active
element 1006 is deployed or extended (see FIG. 39) out of the
distal end 1012 of the probe body 1002 and comes into contact with
the patient's tissue. As shown in FIG. 39, a mesh or other membrane
1010 may be attached to and trail the active element 1006 to
collect tissue cut by the active RF element 1006. This mesh may be
expandable, to enable the collection of a relatively large mass of
tissue. Likewise, the ring-shaped active element 1006 may itself be
expandable in diameter or deformed in shape so as to enable
collection of large or irregularly shaped lesions or specimens.
[0075] While the foregoing detailed description has described
preferred embodiments of the present invention, it is to be
understood that the above description is illustrative only and not
limiting of the disclosed invention. Those of skill in this art
will recognize other alternative embodiments and all such
embodiments are deemed to fall within the scope of the present
invention. Thus, the present invention should be limited only by
the claims as set forth below.
* * * * *