U.S. patent application number 10/806867 was filed with the patent office on 2004-09-09 for electrode arrangement for a surgical instrument for electrothermal coagulation in tissue.
Invention is credited to Desinger, Kai.
Application Number | 20040176761 10/806867 |
Document ID | / |
Family ID | 7891651 |
Filed Date | 2004-09-09 |
United States Patent
Application |
20040176761 |
Kind Code |
A1 |
Desinger, Kai |
September 9, 2004 |
Electrode arrangement for a surgical instrument for electrothermal
coagulation in tissue
Abstract
There is provided a surgical instrument for electrothermal
coagulation of tissue, which includes a front cylinder at the
distal end of the instrument having a distal tip, an elongate
carrier, and two spaced cylindrical or strip-shaped electrodes at
or on the carrier which are connectable to an HF-ac voltage
source.
Inventors: |
Desinger, Kai; (Berlin,
DE) |
Correspondence
Address: |
Beck & Tysver, P.L.L.C.
Suite 100
2900 Thomas Avenue S.
Minneapolis
MN
55416
US
|
Family ID: |
7891651 |
Appl. No.: |
10/806867 |
Filed: |
March 23, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10806867 |
Mar 23, 2004 |
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09868303 |
Jul 30, 2001 |
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6723094 |
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09868303 |
Jul 30, 2001 |
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PCT/EP99/10079 |
Dec 17, 1999 |
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Current U.S.
Class: |
606/50 |
Current CPC
Class: |
A61B 2018/00148
20130101; A61B 2018/126 20130101; A61B 18/14 20130101; A61B
2018/00815 20130101; A61B 2090/306 20160201; A61B 2018/00107
20130101; A61B 18/1477 20130101; A61B 2018/00589 20130101; A61B
2017/00084 20130101; A61B 2018/2025 20130101; A61B 2018/00023
20130101; A61B 2018/00577 20130101; A61B 2018/00029 20130101; A61B
18/1492 20130101; A61B 2018/00083 20130101; A61B 2018/1425
20130101 |
Class at
Publication: |
606/050 |
International
Class: |
A61B 018/14 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 18, 1998 |
DE |
198 58 599.3 |
Claims
1. An electrode arrangement for a surgical instrument for
electrothermal coagulation in tissue, comprising: a front cylinder
at the distal end of the instrument with a distal tip, an elongate,
electrically insulating carrier proximally adjoining the front
cylinder, at least two spaced electrodes on the carrier, which are
connectable to an AC voltage source, characterized in that the
electrodes are of a strip-shaped configuration and extend along the
carrier.
2. An electrode arrangement for a surgical instrument according to
claim 1 wherein the electrodes extend parallel to the longitudinal
axis of the carrier.
3. An electrode arrangement for a surgical instrument according to
claim 1 wherein the carrier is of a uniform cross-section in the
longitudinal direction and wherein the electrodes are disposed in
mutually diametrically opposite relationship on the carrier
cross-section.
4. An electrode arrangement for a surgical instrument according to
claim 1 wherein the electrodes extend on the carrier along spaced
helical lines.
5. An electrode arrangement for a surgical instrument as set forth
in claim 1 wherein the carrier is in the form of a metal tube with
an externally disposed insulating coating.
6. An electrode arrangement for a surgical instrument according to
claim 5 wherein the metal tube includes an outer layer of titanium
or aluminum which at its surface carries a Ti-oxide layer or an
Al-oxide layer as an insulating layer.
7. An electrode arrangement for a surgical instrument according to
claim 1 further comprising a hollow duct in the longitudinal
direction of the carrier, through which an optical waveguide
passes.
8. An electrode arrangement for a surgical instrument according to
claim 1 wherein the tip of the front cylinder is of a conical
configuration.
9. An electrode arrangement for a surgical instrument according to
claim 1 wherein the tip of the front cylinder is of a wedge-shaped
configuration.
10. An electrode arrangement for a surgical instrument according to
claim 1 wherein the electrodes are applied to the carrier in the
form of thin conductive layers.
11. An electrode arrangement for a surgical instrument according to
claim 1 wherein the carrier comprises flexible material.
12. An electrode arrangement for a surgical instrument according to
claim 11 wherein the carrier is an optical waveguide, on the
insulating outside sheath of which the electrodes are applied in a
strip configuration an elastically.
13. An electrode arrangement for a surgical instrument according to
claim 1 wherein the carrier comprises rigid material.
14. An electrode arrangement for a surgical instrument for
electrothermal coagulation in tissue, comprising: a) a front
cylinder at the distal end of the instrument; b) an elongate
carrier proximally adjoining the front cylinder; c) two electrodes
which extend in the longitudinal direction of the carrier and which
are connectable to an AC voltage source; wherein the carrier
includes externally disposed, self-supporting metal bar profile
members which extend in the longitudinal direction and which are
connected together by means of one or more insulating spacer
elements and form the electrodes.
15. An electrode arrangement for a surgical instrument according to
claim 14 wherein the optical waveguide is passed in the
longitudinal direction between the bar profile members, as a spacer
element.
16. An electrode arrangement for a surgical instrument according to
claim 15 wherein the optical waveguides extend laterally visibly
between the bar profile members.
17. An electrode arrangement for a surgical instrument according to
claim 14 wherein the cross-section of the bar profile members
corresponds to the segment of a circular area.
18. An electrode arrangement for a surgical instrument according to
claim 14 wherein the cross-section of the bar profile members which
are uniform in the longitudinal direction corresponds to a
peripheral portion of a tube.
19. An electrode arrangement for a surgical instrument according to
claim 18 wherein the bar profile members are disposed in mutually
opposite relationship on the outside sheath of an optical
waveguide.
20. An electrode arrangement for a surgical instrument for
electrothermal coagulation in tissue, including a) a front cylinder
at the distal end of the instrument; b) at least one elongate,
electrically insulating carrier proximally behind the front
cylinder; c) two spaced cylindrical electrodes; d) a hollow duct in
the longitudinal direction through the carrier; and e) connecting
lines which are passed through the hollow duct for connecting the
electrodes to an AC voltage source; wherein the electrodes are
cylindrical tube portions of metal which are arranged at a
predetermined spacing from each other in the longitudinal direction
in axial alignment with the carrier.
21. An electrode arrangement for a surgical instrument according to
claim 20 wherein the carrier is a flexible tube of insulating
material.
22. An electrode arrangement for a surgical instrument according to
claim 20 further comprising a central opening in the front cylinder
provided as a prolongation of the hollow duct, said central opening
having arranged therein a temperature sensor whose connecting line
is taken out through the hollow duct to the proximal end of the
instrument.
23. An electrode arrangement for a surgical instrument according to
claim 20 wherein the outside diameter of the front cylinder
approximately corresponds to the outside diameter of the
electrodes.
24. An electrode arrangement for a surgical instrument according to
claim 20 wherein the axial length of the electrodes is larger than
their diameter.
25. An electrode arrangement for a surgical instrument according to
claim 20 wherein the axial length of the electrodes is larger than
double their diameter.
26. An electrode arrangement for a surgical instrument according to
claim 20 wherein the spacing of the two electrodes is approximately
equal to or smaller than the outside diameter of the
electrodes.
27. An electrode arrangement for a surgical instrument according to
claim 20 wherein the distal front cylinder includes insulating
material or metal.
28. An electrode arrangement for a surgical instrument according to
claim 20 wherein the temperature sensor in the opening in the front
cylinder is embedded in a synthetic resin or adhesive bed.
29. An electrode arrangement for a surgical instrument according to
claim 28 wherein the outside diameter of the electrodes corresponds
to the outside diameter of the front cylinder and wherein the
intermediate space between the electrodes is filled by insulating
material to the outside diameter of the electrodes.
30. An electrode arrangement for a surgical instrument according to
claim 20 wherein the first electrode axially extends in the distal
direction a predetermined length over the front cylinder.
31. An electrode arrangement for a surgical instrument according to
claim 20 wherein the electrodes are formed from self-supporting
metal tube portions.
32. An electrode arrangement for a surgical instrument according to
claim 31 wherein the first electrode is arranged between the front
cylinder and an insulating tubular first carrier, the second
electrode is arranged between the first carrier and an insulating
tubular second carrier, and wherein the electrodes rest with their
end portions on the front cylinder, and the first and second
carriers.
33. An electrode arrangement for a surgical instrument according to
claim 20 wherein the first electrode extends between the front
cylinder and the insulating tubular carrier and the second
electrode extends from the carrier to the proximal end portion, and
wherein the electrodes bear with their end portions on the front
cylinder and the carrier.
34. An electrode arrangement for a surgical instrument according to
claim 33 wherein the second electrode is proximally covered over a
predetermined axial length with an insulating layer.
35. An electrode arrangement for a surgical instrument according to
claim 20 further comprising a flushing tube within the hollow duct,
which extends from the proximal end of the instrument to the front
cylinder and discharges fluid at its distal end into the hollow
duct in which the fluid flows back to the proximal end of the
instrument.
36. An electrode arrangement for a surgical instrument according to
claim 20 wherein the end portions of the electrodes, which overlap
the front cylinder and the carrier or carriers, are covered on
their outer periphery by an insulating layer.
37. An electrode arrangement for a surgical instrument according to
claim 20 wherein the tip of the front cylinder is of a conical or
wedge-shaped or rounded-off configuration.
38. An electrode arrangement for a surgical instrument according to
claim 20 further comprising a self-supporting metal tube between
the front cylinder and the carrier, with a distal tube portion and
a proximal tube portion, a cylindrical insulating layer on the
proximal tube portion and a cylindrical metal layer at the proximal
end of the insulating layer, wherein the distal tube portion forms
the first electrode and the proximal metal layer forms the second
electrode.
39. An electrode arrangement for a surgical instrument according to
claim 20 further comprising a self-supporting metal tube between
the front cylinder and the carrier, with a distal tube portion and
a proximal tube portion, a cylindrical insulating layer on the
distal tube portion and a cylindrical metal layer at the distal end
of the insulating layer, wherein the distal metal layer forms the
first electrode and the proximal tube portion forms the second
electrode.
40. An electrode arrangement for a surgical instrument according to
claim 20 wherein the carrier has a hollow duct which goes into the
hollow duct of the metal tube or the tube portions, and wherein the
connecting lines for the electrodes are passed through the hollow
duct of the carrier to the proximal end of the instrument.
41. An electrode arrangement for a surgical instrument according to
claim 20 further comprising a flushing tube passing through the
hollow duct of the carrier and the metal tube or the tube portions
in the longitudinal direction, said flushing tube extending to the
front cylinder, through which flushing tube fluid is discharged at
the distal end into the hollow duct, which outside the flushing
tube in contact with the metal tube flows back through the hollow
duct of the tube and the hollow duct of the carrier to the proximal
end of the instrument.
42. An electrode arrangement for a surgical instrument according to
claim 38 further comprising an insulating inner tube in the hollow
duct of the carrier and the metal tube, through which a connecting
line for the electrode at the distal end of the tube is passed.
43. An electrode arrangement for a surgical instrument according to
claim 38 wherein the front cylinder comprises insulating
material.
44. An electrode arrangement for a surgical instrument according to
claim 38 wherein the metal tube comprises aluminum or titanium and
that the insulating layer is formed from the metal tube of aluminum
oxide or titanium oxide.
45. An electrode arrangement for a surgical instrument for
electrothermal coagulation in tissue, comprising: a) a front
cylinder of metal at the distal end of the instrument; b) an
elongate cylindrical carrier of insulating material proximally
adjoining the cylinder; and c) two spaced cylindrical electrodes;
wherein the metal front cylinder is rounded off at the distal end
and adjoining the round end portion has a cylinder portion of
predetermined length, wherein the front cylinder forms the first
electrode and wherein disposed on the carrier at a predetermined
axial spacing from the front cylinder is a metal layer as the
second electrode.
46. An electrode arrangement for a surgical instrument according to
claim 45 further comprising a hollow duct provided through the
carrier and the front cylinder to the round end portion a flushing
tube extending through said hollow duct and which, at the distal
end, discharges fluid which flows back in the hollow duct--outside
the flushing tube--to the proximal end.
47. An electrode arrangement for a surgical instrument according to
claim 45 wherein the front cylinder can be secured with its
proximal end in an annular opening of the carrier and that an oxide
layer is externally applied to the metal front cylinder in the
overlap region between the carrier and the front cylinder.
48. An electrode arrangement for a surgical instrument according to
claim 20 wherein the axial length of the electrodes is greater than
the axial spacing of the two electrodes from each other.
49. An electrode arrangement for a surgical instrument according to
claim 20 characterized in the axial length of the electrodes is
greater than the diameter of the electrodes.
50. An electrode arrangement for a surgical instrument according to
claim 20 characterized in that the axial length of the electrodes
is greater than the axial length of the lengthwise portion occupied
by the insulator element.
51. An electrode arrangement for a surgical instrument according to
claim 20 wherein the axial length of the electrodes is greater than
the outside diameter of the front cylinder or the outer conductor
respectively.
52. An electrode arrangement for a surgical instrument according to
claim 20 wherein the axial spacing of the electrodes from each
other is approximately equal to or smaller than the outside
diameter of the front cylinder.
53. An electrode arrangement for a surgical instrument according to
claim 20 wherein the self-supporting metal tube or tube portions
and/or the metal cylinder body which are provided to form the
electrodes comprise titanium or aluminum and that the insulating
layers which are provided on the metal tube or the metal tube
portions are applied by anodic oxidation of the metal surface in an
electrolyte bath.
54. An electrode arrangement for a surgical instrument according to
claim 20 wherein at least one of the connecting lines for
connection of the electrodes has at one end a portion of spring
metal which is clamped radially outwardly in the hollow duct
against the inside surfaces of the electrodes.
Description
[0001] The invention concerns an electrode arrangement for a
surgical instrument for electrothermal coagulation of tissue, which
includes a front cylinder at the distal end of the instrument
having a distal tip, a carrier proximally adjoining the front
cylinder, and two electrodes which are connectable to an ac voltage
source.
[0002] Using the application of high-frequency alternating currents
(for example in the frequency range of between 300 KHz and 2 MHz)
to generate high temperatures for tissue coagulation and for tissue
division has long been known in surgery. In a practical context,
so-called monopolar electrode arrangements or bipolar electrode
arrangements are used for introducing the HF-current into the
tissue.
[0003] In the case of the monopolar arrangements, an
electrode--also referred to as the neutral electrode--is applied in
the form of an electrode of large area to the skin of the patient
in the proximity of the treatment location and fixed there and
earthed or connected to ground. A second electrode which is
manipulated by the operator--also referred to as the active
electrode--is connected to the ac voltage source. In terms of its
shape, the electrode is so adapted to the respective use, in
particular the size of the tissue area to be treated, that both the
operational time and also the thermal loading of the region of the
body or organ involved are reasonable and they coagulate only the
desired area of tissue.
[0004] In the case of arrangements for bipolar HF-thermotherapy,
both electrodes are connected to an HF-generator and arranged with
dimensions which are fixed with respect to each other, for example
on an insulating carrier, and are placed by the operator in the
immediate proximity of the treatment location and generally also
actively guided.
[0005] WO 97/17009 discloses a bipolar electrode arrangement with a
fluid duct by way of which flushing fluid can be introduced into
the operational area. Two or three electrodes are arranged in the
form of a cone portion on a conical distal tip of the instrument
which can be introduced into the tissue, wherein the
electromagnetic HF-field is formed between the electrodes and is
intended to coagulate the surrounding tissue.
[0006] WO 96/34569 and the documents referred to in the associated
international search report disclose systems and processes for the
coagulation of body tissue while maintaining a pre-calculated
maximum tissue temperature, in which fluid cooling or
thermoelectric cooling is provided during the actual tissue
coagulation procedure. Those known arrangements are intended for
the introduction into body cavities by way of natural accesses.
[0007] U.S. Pat. No. 4,832,048 as well as WO 95/10320 and WO
99/11186 or EP 96 945 879.3 and WO 98/19613, WO 96/18349 and WO
81/03272 also disclose surgical instruments which treat tissue by
means of HF-thermotherapy by means of a bipolar electrode
arrangement.
[0008] The known surgical instruments for bipolar HF-thermotherapy
are often expensive to manufacture and, for the various areas of
use involved, they often suffer from disadvantages which frequently
result in locally inaccurate tissue treatment which in particular
in part does not reach the tissue to be treated or thermally
overloads sound tissue.
[0009] Therefore the object of the present invention is to develop
an electrode arrangement for a surgical instrument of the kind set
forth in the opening part of this specification, such that it is
simple to manufacture and use and permits precise localizable
treatment of the tissue, while at the same time sparing surrounding
sound tissue.
[0010] That object is attained by an electrode arrangement for a
surgical instrument for thermoelectric coagulation of tissue,
including an electrically conductive front cylinder at the distal
end of the instrument, with a distal tip and with a cylindrical
first electrode, a tubular outer conductor proximally adjoining the
front cylinder and with a cylindrical second electrode, an
insulator element between the front cylinder and the outer
conductor, wherein the electrodes are connectable to an ac voltage
source, characterised by a bar-shaped inner conductor in the outer
conductor and an insulating tube between the inner conductor and
the outer conductor.
[0011] The advantages of the invention are in particular that the
electrode arrangement is of a particularly simple structure,
wherein more specifically the front cylinder forms an electrode and
that the proximally adjoining outer conductor which is insulated by
way of an insulator element forms the second electrode so that the
ac voltage source is connectable to the front cylinder and from the
outside directly to the outer conductor by way of the bar-shaped
inner conductor which is separated by an insulating tube outer
conductor.
[0012] The insulating element has between the front cylinder and
the outer conductor a radial partition which at the outside goes
into a cylindrical casing wall which surrounds the front cylinder
and/or the outer conductor in closely fitting relationship
therewith over a predetermined axial lengthwise portion. The inner
conductor is connectable to the front cylinder through that
partition of the insulating element. Preferably, embodied between
the front cylinder and the inner conductor is a releasable screw
connection in which the inner conductor carries at its distal end a
male screwthread which can be screwed to a corresponding axial
female screwthread in the front cylinder. The advantages of this
embodiment are in particular that the cup-like insulator element
can be applied in the form of an insulating layer directly to the
metal front cylinder and/or the metal outer conductor, in such a
way that the separating surface between the front cylinder and the
outer conductor and a lengthwise portion, axially adjoining same,
of the outside surface has a coating with an insulating material. A
coating of that kind can be produced for example in accordance with
the invention by anodization of the surfaces in question in an
electrolyte bath if the front cylinder and/or the outer conductor
comprise an anodizable metal, for example titanium or aluminum.
[0013] Depending on the respective purpose of use the electrode
arrangement for an instrument can be of a flexible nature so that
in that case the inner conductor, the outer conductor, the
insulating tube and possibly also the insulator element comprise an
elastic material. In the case of a flexible surgical instrument of
that kind, the bipolar electrode arrangement can under some
circumstances be more easily moved to the specific treatment
location. Alternatively however the inner conductor and the outer
conductor can be of a straight and rigid configuration, in which
case then the front cylinder and the outer conductor are arranged
in mutually coaxially aligned arrangement and can then be moved to
the treatment location by a rectilinear translatory movement. In
regard to certain treatment locations it may also be particularly
advantageous to angle the instrument in the lengthwise
direction.
[0014] In all embodiments the outer conductor and the front
cylinder are of substantially the same outside diameter in order to
provide for unimpeded sliding movement of the electrode arrangement
in the tissue.
[0015] Preferably the front cylinder, over its axial lengthwise
portion which is not covered by the insulator element, forms the
first electrode and the outer conductor, over the entire axial
lengthwise portion, insofar as same is not covered by the insulator
element, forms the second cylindrical electrode. The axial length
of the electrodes is preferably greater than the axial length of
the insulator element and it is also greater than the outside
diameter of the front cylinder and the outer conductor. Preferably
the length of the outer conductor is a multiple of the length of
the front cylinder. If, in this embodiment, the tissue adjoining
the outside surface of the instrument is coagulated and as a result
becomes of high resistance, then in this embodiment of the
invention the electromagnetic field can be displaced outwardly into
adjoining tissue regions because there is a suitably long second
electrode so that, if the tissue has become of high resistance
adjoining the outside surface, the electromagnetic field can move
radially outwardly and in so doing still ends at the second
electrode. With this embodiment therefore it is possible to
implement a coagulation effect which moves in a defined fashion
into the tissue and which comes to an end when the field extends
from the first electrode to the proximal end of the second
electrode.
[0016] Conversely it has been found that the commencement of
coagulation is optimal when the two electrodes are at a relatively
small axial spacing from each other, which is approximately of the
order of magnitude of the outside diameter or only slightly
larger.
[0017] In a preferred embodiment of the invention the inner
conductor and the front cylinder are provided with a central hollow
duct which issues from the distal tip of the front cylinder and
which contains an optical waveguide which can be acted upon with
visible laser light. In that way light can be passed to the tip of
the applicator. If then for example that applicator is inserted
into thin-walled regions of the body, for example in the nasal
concha for therapy of concha hyperplasia, then the light issuing at
the tip makes it possible to locate the position of the tip in the
nasal concha by the doctor implementing the treatment using the
naked eye. The doctor can therefore see at any time where the tip
of the electrode arrangement is disposed, in the nasal concha. The
above-described surgical instrument is suitable for dynamic use,
for example it is inserted into the enlarged nasal concha and then,
with HF-power activated, withdrawn from the nasal concha, thereby
producing a tubular coagulation zone which has formed around the
path of the electrode arrangement.
[0018] In accordance with a further preferred embodiment of the
invention, the front cylinder which is electrically connected to
the inner conductor and the outer conductor are separated from each
other by an insulating annular body. Preferably the insulating
annular body is made from translucent or partially translucent
material and disposed in the annular body is a light source which
discharges its light to the exterior through the annular body,
preferably in the form of stray or scattered light. In accordance
with a preferred embodiment of this instrument the inner conductor
has a hollow duct which terminates in the insulating annular body
and which accommodates an optical waveguide. In the region of the
annular body radially into the fiber core of the optical waveguide
the inner conductor is provided with incisions so that light issues
radially at the incisions from the optical waveguide and, through
the annular body, makes that zone of the bipolar electrode
arrangement which is between the two electrodes and in which
therefore coagulation of the tissue respectively occurs, visible to
the doctor carrying out the treatment. In the case of thin-walled
bodies therefore the doctor performing the treatment always sees
directly with his own eyes that location at which coagulation is
taking place. It is thereby possible to treat the tissue in a
particularly accurate and local fashion. Depending on the
requirements involved the tip of the front cylinder may be conical
or wedge-shaped.
[0019] The object of the invention is further attained by an
electrode arrangement for a surgical instrument for electrothermal
coagulation of tissue, including a front cylinder at the distal end
of the instrument with a distal tip, an elongate, electrically
insulating carrier proximally adjoining the front cylinder, at
least two spaced electrodes on the carrier, which are connectable
to an ac voltage source, characterised in that the electrodes are
of a strip-shaped configuration and extend along the carrier.
[0020] The advantages of the invention lie in particular in the
simplicity of structure and the electrodes which extend in a
strip-shaped configuration along the carrier. Particularly when the
two electrodes extend parallel to the longitudinal axis of the
carrier, this electrode arrangement is suitable for therapy in
respect of concha hyperplasia. The applicator, that is to say the
electrode arrangement, is used statically in that case, in other
words, the electrode arrangement is pierced into the enlarged nasal
concha and remains fixed in a position with active HF-power. In
that procedure, due to the specific electrode configuration
involved, the desired tubular coagulation zone is produced without
the need to move the applicator in the tissue. A further advantage
is the particularly simple structure which makes it possible to
implement connection of the HF-generator at the proximal end of the
carrier directly--from the exterior--to the electrodes.
[0021] If the electrodes extend parallel to the longitudinal axis
of the carrier and for example are disposed in mutually diametrally
opposite relationship on the preferably circular carrier
cross-section, then the result is two coagulation zones extending
in the longitudinal direction, between the two electrodes. If in
contrast the electrodes are disposed on the carrier along spaced
helical lines, then a correspondingly helical zone of the tissue is
treated and coagulated. In the event of an additional axial
movement of the electrode arrangement, a circular coagulated
enclosing passage is then formed around the carrier.
[0022] In accordance with a particularly preferred embodiment of
the invention the carrier is in the form of a metal tube carrying
an externally disposed insulating layer on which the strip-shaped
electrodes are disposed. If the metal tube used comprises a metal
which can be anodically oxidized in an electrolysis bath, for
example therefore titanium or aluminum, then production of the
insulating carrier is particularly simple, more specifically if the
outside surface of the carrier is electrolytically anodized to form
a layer of titanium oxide or aluminum oxide. In this embodiment
also it is possible to draw through a hollow duct which passes
axially through the carrier and issues at the tip of the front
cylinder, an optical waveguide which makes the position of the tip
of the front cylinder visible to the operator--when dealing with
correspondingly thin tissue--or in the event of implementing a
treatment just under the skin, whereby the operator can guide the
arrangement in properly targeted fashion. The optical waveguide can
be supplied for example with visible laser light. The distal tip of
the front cylinder is advantageously either of a conical or a
wedge-shaped configuration and the electrodes are applied in the
form of thin conducting metal layers to the carrier.
[0023] In accordance with a preferred embodiment of the invention
the carrier can be made from a flexible material on which the
strip-shaped electrodes are carried. The carrier used can be for
example an optical waveguide, on the insulating outer sheath of
which the electrodes are disposed elastically and in a strip-shaped
configuration. The electrode arrangement can then more easily be
introduced through body openings to the treatment location.
[0024] In this embodiment also the axial length of the electrodes
is preferably greater than the outside diameter of the front
cylinder and carrier which are both preferably of the same outside
diameter in order to permit the electrode arrangement to be easily
introduced by a sliding movement into the tissue.
[0025] The object of the invention is further attained by an
electrode arrangement for a surgical instrument for electrothermal
coagulation in the tissue, including a front cylinder of metal or
insulating material at the distal end of the instrument, the front
cylinder is frontally pointed or rounded-off, an elongate carrier
proximally adjoining the front cylinder, two electrodes which
extend in the longitudinal direction of the carrier and which are
connectable to an ac voltage source, characterised in that the
carrier includes externally disposed, self-supporting metal bar
profile members which extend in the longitudinal direction and
which are connected together by means of one or more insulating
spacer elements and form the electrodes.
[0026] The advantages of the last-mentioned embodiment of the
invention are in particular that the electrodes extend in the
longitudinal direction of the carrier and are self-supporting metal
bar profile members forming the carrier, whereby manufacturing
steps can be omitted in manufacture of the electrode arrangement.
In a particularly preferred configuration the one or more
insulating spacer elements between the electrodes is or are optical
waveguides which are guided in the longitudinal direction between
the bar profile members and give off light to the distal tip of the
instrument so that the operator can at any time locate the tip of
the instrument by visual means when the instrument is used in
thin-walled parts of the body. In a particularly preferred feature
the externally disposed visible optical waveguides can also be
provided with radial countersinks or incisions ground therein,
which provide that light also issues radially at those locations.
That accordingly shows the operator over what axial distance the
instrument--with HF-energy activated--is also coagulating tissue.
The cross-section of the bar profile members corresponds, when
considered together, preferably to a circular surface area, but
alternatively the cross-section of the bar profile members can also
be in the form of a portion of the periphery of a tube, in which
case then the bar profile members are for example preferably fixed
in mutually opposite relationship on the outside sheath of an
optical waveguide and in that way form a rigid carrier with
externally disposed strip-shaped electrodes extending in the
longitudinal direction.
[0027] The object of the invention is further attained by an
electrode arrangement for a surgical instrument for
thermoelectrical coagulation in tissue, including a front cylinder
of metal or insulating material at the distal end of the
instrument, wherein the front cylinder is frontally pointed or
rounded-off, an elongate carrier proximally adjoining the front
cylinder, and two electrodes which extend in the longitudinal
direction of the carrier and which are connectable to an ac voltage
source, characterised in that the electrodes (2, 4) are cylindrical
tube portions (82, 84) of metal which are arranged at a
predetermined spacing from each other in axial alignment with the
carrier in the longitudinal direction.
[0028] In accordance with this preferred embodiment of the
invention the first electrode can be in the form of a
self-supporting tube portion which is carried between the front
cylinder and an insulating tubular first carrier and the second
electrode can also be in the form of a self-supporting tube portion
arranged between the first carrier and a second tubular carrier,
wherein the end portions of the electrodes are supported on the
front is cylinder, the first and the second carrier over a
predetermined lengthwise portion. Alternatively it is also possible
for the second electrode to extend as far as the proximal end
portion. Particularly preferably in this embodiment the lengthwise
portions of the electrodes which bear on the first and/or the
second carrier are covered with an insulating layer. In addition,
provided within the hollow duct is a flushing tube which extends
from the proximal end of the instrument to the front cylinder, that
is to say also through the tube portions which form the electrodes,
and extends as far as the front cylinder and discharges fluid at
the distal end into the hollow duct in which the fluid--in contact
with the electrodes--flows back to the proximal end of the
instrument.
[0029] Cooling of the electrode surfaces by means of a flushing
fluid means that the so-called "hot-spot" of coagulation is
displaced by approximately between two and three millimeters from
the surface of the instrument into the tissue. The cooling action
ensures that the tissue-electrode contact surface is always kept
below a predetermined temperature and therefore does not dry out to
such a severe degree, so that the introduction of energy into the
adjoining tissue is also guaranteed, over a relatively long period
of time. It is quite particularly advantageous in that respect that
the lengthwise portions of the electrodes which rest on the
insulating carriers--or in a specific embodiment also on the front
cylinder which is in the form of an insulating body--and are
therefore not directly cooled by the cooling fluid, are covered
with an insulating layer. In that way those lengthwise portions
which are cooled to a lesser degree and which consequently heat up
to a greater degree than the cooled electrode portions are covered
over by the insulator and therefore come into contact with the
adjoining tissue only by way of the comparatively cooler insulating
layer. Thus, the consequence of covering over the end portions of
the electrodes, which are not cooled by the flushing fluid, by
means of insulating layers, is that the adjoining tissue does not
become too hot even in those longitudinal portions, and thus it
does not dry out.
[0030] In a preferred embodiment of the invention a self-supporting
metal tube is provided between the front cylinder and the carrier.
A distal portion of the metal tube serves as the first electrode,
an adjoining proximal tube portion is surrounded by a cylindrical
insulating layer and carries on that insulating layer a metal layer
which serves as the second electrode. Alternatively, the proximal
tube portion may also be used as the second electrode and then
disposed on the distal tube portion is a cylindrical insulating
layer which is coated with a metal layer, wherein that distal metal
layer then serves as the first electrode.
[0031] This embodiment of the invention has the advantage of
affording ease of manufacture and assembly of the bipolar electrode
arrangement. This applies in particular when the metal used is an
anodizable material, for example titanium or aluminum and the
cylindrical insulating layer applied to the tube portion is
produced by anodic oxidation (anodization) of the metal surface, in
which case the metal layer deposited thereon can be produced for
example by vapor deposition or electrolytic coating. In this
embodiment the carrier has a hollow duct which is extended into a
hollow duct through the metal tube. The connecting lines for the
electrodes extend from the electrodes through the hollow duct to
the proximal end of the instrument. In accordance with the
invention this preferred embodiment thereof also provides that a
flushing tube is taken through the hollow duct, which extends as
far as the front cylinder and discharges cooling fluid at the
distal end into the hollow duct.
[0032] Advantageously, provided as a prolongation of the hollow
duct of the carrier in the front cylinder is an opening in which
there is disposed a temperature sensor whose connecting line is
passed through the hollow duct to the proximal end of the
instrument. In that way it is possible--for example for therapy in
respect of benign prostate hyperplasia to fit a temperature sensor
or thermistor into the tip of the front cylinder, which can be used
to measure the tissue temperature. Preferably the carrier is formed
from a flexible insulating hoze or tube and the electrodes are
cylindrical self-supporting tube portions of metal which are fixed
at predetermined spacings on the carrier. In this embodiment of the
invention the outside diameter of the front cylinder also
corresponds to the outside diameter of the electrodes and the axial
length of the electrodes is greater than the diameter, while the
axial spacing of the two electrodes from each other is
approximately equal to or smaller than the outside diameter
thereof. It has been found that, with that dimensioning, the
electrical field which causes coagulation of the tissue can be
sufficiently strongly produced and also--after the tissue adjoining
the outside surface is coagulated--can be propagated sufficiently
far into the tissue so that an advantageous large coagulation zone
is produced.
[0033] The temperature sensor in the opening in the front cylinder
is preferably embedded in synthetic resin or in an adhesive bed
which provides for good conduction of the temperature of the metal
front cylinder to the temperature sensor. The outside diameter of
the electrodes and the outside diameter of the front cylinder are
identical and the intermediate space between the electrodes is
filled with insulating material so that this lengthwise portion is
also of the outside diameter which occurs elsewhere. That provides
for a uniform cross-section over the distal tip to the proximal end
of the second electrode, in contrast to which the flexible carrier,
adjoining same, can be of a reduced outside diameter. The
consequence of the constant dimension of the outside diameters in
the region of the front cylinder and the electrodes is that the
instrument can be introduced into the tissue easily and in
particular without impediment.
[0034] The object of the invention is further attained by an
electrode arrangement for a surgical instrument for electrothermal
coagulation of tissue, including a front cylinder of metal at the
distal end of the instrument, an elongate cylindrical carrier
proximally adjoining the cylinder and comprising insulating
material, two spaced cylindrical electrodes, characterised in that
the metal front cylinder is rounded-off at the distal end and
adjoining the round end portion has a cylinder portion of
predetermined length, that the front cylinder forms the first
electrode, and that a metal layer as the second electrode is
disposed on the carrier at a predetermined axial spacing from the
front cylinder.
[0035] In this preferred embodiment of the invention, extending
through the carrier is a hollow duct which is extended into the
front cylinder and which accommodates a flushing hoze or tube which
at its distal end discharges flushing fluid which flows back along
the inside wall of the front cylinder and finally between the
carrier and the flushing tube to the proximal end.
[0036] The front cylinder can be fixed with its proximal end in an
annular opening in the carrier and the overlap region between the
carrier and the front cylinder has on its outside an oxide layer on
the metal front cylinder, which ensures that the metal of the front
cylinder which is uncooled at that location does not come into
contact in an overheated condition with the adjoining tissue.
[0037] The carrier can be of both a flexible and a rigid nature
and, as the front cylinder is formed from metal material, this
instrument--by virtue of the active tip--makes it possible to treat
edge tumors which are disposed immediately in front of the
rounded-off front cylinder. A prerequisite for advantageous
functioning of this electrode arrangement is that the dissipation
of heat by the cooling circulation is as far as possible the same
at both electrodes. That is achieved if the mean current density at
the first, that is to say distal electrode is greater than or equal
to the current density at the second, proximal electrode. That
condition is met when the surface area A.sub.1 of the first
electrode is smaller than or equal to the surface area A.sub.2 of
the second electrode. Insofar as the surface area component of the
round end portion--with its radius R--is also taken into
consideration, that gives the following relationship in respect of
the lengths L.sub.1, L.sub.2 of the first and second electrodes:
L.sub.1+R<L.sub.2. If very great lengths L.sub.2 of the second
electrode are to be implemented and if nonetheless the degree of
flexibility of the applicator is to be maintained, then the second
electrode can be constructed by coating the flexible carrier with a
metal layer.
[0038] The object of the invention is further attained by an
electrode arrangement for a surgical instrument for electrothermal
coagulation of tissue including: an elongate cylindrical carrier
comprising a metal tube or a metal bar, two spaced cylindrical
electrodes on the carrier, characterised in that the first
electrode is a distal portion of the carrier, that on a portion
axially adjoining same an insulating layer is applied to the
carrier, and that a cylindrical metal layer as the second electrode
is arranged on the insulating layer at a predetermined axial
spacing from the first electrode.
[0039] In this embodiment of the invention the front cylinder and
the carrier are embodied in the form of an integral metal tube or
metal bar whose distal end is pointed. A distal portion of the
metal tube or metal bar forms the first electrode. Adjoining same,
an insulating layer is applied to the carrier and then a
cylindrical metal layer is deposited on the insulating layer in the
proximal region of the insulating layer and forms the second
cylindrical electrode. The insulating layer can be embodied by a
plastic hoze or tube to which a metal coating is applied, as the
second electrode. The metal carrier with the distal tip represents
a bipolar electrode arrangement in the form of a cannula or needle
and is suitable in particular for therapy in respect of enlarged
terminal vessels such as for example finely mottled varicose veins.
The electrode arrangement is pierced with its tip in the
longitudinal direction into the enlarged vessel. Upon activation of
the HF-power the blood and the vessel wall coagulate primarily
around the first electrode. When that happens the vessel contracts
so as to afford a closure effect with the result than then no
further blood can flow into the vessel whereby the vessel is no
longer perceptible through the skin and the desired cosmetic effect
is achieved.
[0040] It is particularly advantageous to employ insulating layers
which are used in bipolar electrode arrangements, comprising
ceramic material. The advantage of this material is that it has a
high level of mechanical strength and can be easily produced by
means of electrolytic anodization (eloxation) for example on
titanium in the form of titanium oxide or in the case of aluminum
in the form of aluminum oxide. The thickness of the layer depends
on the electrical voltage used in the electrolysis operation.
Instead of titanium, various titanium alloys on which the ceramic
layer is produced by anodic oxidation are also suitable as the
starting material involved. In order to implement complete or
partial coating in that way with titanium or suitable titanium
alloys or aluminum, firstly the corresponding metal body is
subjected to a preliminary chemical cleaning operation in order to
obtain grease-free and oxide-free surfaces. Then, the places which
are not to be coated are masked. Masking can be effected by means
of special lacquers or layers but also by shrink tubes. For
anodically applying a ceramic layer, the starting material, that is
to say titanium, titanium alloys or aluminum is to be electrically
contacted and subjected to voltage as the anode.
[0041] In order for example--based on titanium as the starting
material --to apply a titanium oxide ceramic layer, the following
steps are to be taken: in order to convert the titanium at its
surface into its ion phase, a suitably molar acid in aqueous
solution is to be used. The molar solutions in question are between
0.1 and 1 molar H.sub.2SO.sub.4 (sulfuric acid) and H.sub.3PO.sub.4
(phosphoric acid) respectively. By the application of a suitable dc
voltage, oxygen is deposited at the electrode, the titanium
electrode which is to be coated in this case, and bonds to the
ionized titanium surface and is converted to titanium oxide.
Depending on the respective layer thickness involved, the dc
voltages and currents to be used are between 10V and 500V at
maximum currents of 1 A. As a result the oxidation procedure passes
through a plurality of oxidation stages (titanium oxides) depending
on the respective length of the procedure. The layer thicknesses
which are to be achieved with these processes are of the order of
magnitude of between 20 and 30 .mu.m. By means of the layer
thicknesses which are to be represented by way of interference
colors, due to the differing light refraction at the interface with
the metal (the oxide layer is transparent), the latter can be
represented proportionally over a color spectrum. With that method
it is possible efficiently to provide specific paramagnetic
electrodes of titanium--or titanium alloys such as
TiAl.sub.6V.sub.4--with a dielectric ceramic layer, being variable
in terms of layer thickness and/or color.
[0042] Besides the good dielectric properties of the ceramic layers
produced in that way, the tribological properties are also
excellently well suited to possibly increasing the levels of
abrasion strength and surface quality. These colored ceramic layers
are also suitable for the stable marking of needles, cannulae or
probes. A proportional interference color is to be selected by way
of the choice of the layer thickness. It is possible in that way to
set colors of grey, gold, violet and on to blue.
[0043] In accordance with a further preferred embodiment of the
invention at least one of the connecting lines which serve to
connect the electrodes has at its end a portion of spring metal,
preferably spring wire, which is of such a configuration that it is
clamped in the hollow duct--within the electrodes--radially
outwardly against the inside surface of the electrodes and thereby
sufficiently reliably and securely produces electrical contact. The
spring metal portion of the connecting lines of that configuration
is preferably wound to form a spiral or coil spring which is acted
upon by a predetermined tensile stress in the spiral wire, the
winding of which therefore under that tensile stress is of a
reduced diameter so that it can be easily introduced from the
exterior into the cavity of the electrode. The tensile stress
acting on the spring wire is then removed, the spiral spring then
attains its full outside diameter and in so doing bears in
self-clamping relationship from the interior against the inside
surfaces of the electrodes. In order easily to be able to implement
introduction of the corresponding spring portions at the end of the
connecting lines, it is possible to use a corresponding special
tool which makes it possible to insert the spiral spring of reduced
diameter, then remove the tensile biasing of the spiral spring
wire, and thus cause the spiral spring to bear against the inside
surface of the electrode.
[0044] Advantageous developments of the invention are characterised
by the features of the appendant claims.
[0045] Embodiments of the invention are described in greater detail
hereinafter with reference to the drawing in which:
[0046] FIG. 1 is a view in longitudinal section through a first
embodiment of a bipolar electrode arrangement for a surgical
instrument,
[0047] FIG. 2 is a view in longitudinal section through a second
embodiment of a bipolar electrode arrangement,
[0048] FIG. 3 is a view in longitudinal section through a third
embodiment of a bipolar electrode arrangement,
[0049] FIG. 4 is a view in longitudinal section through a fourth
embodiment of a bipolar electrode arrangement,
[0050] FIG. 5 is a view in longitudinal section through a fifth
embodiment of the bipolar electrode arrangement,
[0051] FIG. 6 is a view in longitudinal section through a sixth
embodiment of the bipolar electrode arrangement,
[0052] FIG. 7 is a view in longitudinal section through a seventh
embodiment of the bipolar electrode arrangement,
[0053] FIG. 8 is a view in cross-section through the seventh
embodiment,
[0054] FIG. 9 is a view in longitudinal section through an eighth
embodiment of the bipolar electrode arrangement,
[0055] FIG. 10 is a view in cross-section through the eighth
embodiment,
[0056] FIG. 11 is a view in longitudinal section through a ninth
embodiment of the bipolar electrode arrangement,
[0057] FIG. 12 is a view in cross-section through the ninth
embodiment,
[0058] FIG. 13 is a view in cross-section through a tenth
embodiment of the bipolar electrode arrangement,
[0059] FIG. 14 is a view in cross-section through an eleventh
embodiment of the bipolar electrode arrangement,
[0060] FIG. 15 is a side view of a twelfth embodiment of the
bipolar electrode arrangement;
[0061] FIG. 16 is a view in longitudinal section through the
twelfth embodiment,
[0062] FIG. 17 is a view in longitudinal section through a
thirteenth embodiment of the bipolar electrode arrangement with a
pointed front cylinder of insulating material,
[0063] FIG. 18 is a view in longitudinal section through the
thirteenth embodiment with a metal pointed front cylinder,
[0064] FIG. 19 is a view in longitudinal section through the
thirteenth embodiment with a metal frontally rounded-off front
cylinder,
[0065] FIG. 20 is a view in longitudinal section through a
fourteenth embodiment of the bipolar electrode arrangement,
[0066] FIG. 21 is a view in longitudinal section through a
fifteenth embodiment of the bipolar electrode arrangement,
[0067] FIG. 22 is a view in longitudinal section through a
sixteenth embodiment of the bipolar electrode arrangement,
[0068] FIG. 23 is a view in longitudinal section through a
seventeenth embodiment of the bipolar electrode arrangement,
[0069] FIG. 24 is a view in longitudinal section through a
eighteenth embodiment of the bipolar electrode arrangement,
[0070] FIG. 25 is a view in longitudinal section through an
alternative form of the eighteenth embodiment,
[0071] FIG. 26 is a view in longitudinal section through a second
alternative form of the eighteenth embodiment,
[0072] FIG. 27 is a perspective view of a front cylinder with a
partial coating with ceramic material,
[0073] FIG. 28 shows an end portion of a connecting line for the
connection of an electrode,
[0074] FIG. 29 is a perspective view of an electrode formed from a
metal tube with a ceramic coating and a connecting line disposed in
the interior of the tube,
[0075] FIG. 30 is a view in longitudinal section through another
embodiment of bipolar electrode arrangement for a surgical
instrument where the instrument extends angled in the longitudinal
direction,
[0076] FIG. 31 is a view in longitudinal section through still
another embodiment of a bipolar electrode arrangement for a
surgical instrument where the instrument extends angled in the
longitudinal direction.
[0077] FIG. 1 shows a longitudinal section through a first
embodiment of a bipolar electrode arrangement, which is a component
of a surgical instrument for the electrothermal coagulation of
tissue. The electrode arrangement includes an electrically
conductive front cylinder 10 which forms the distal end of the
instrument, that is to say the end which is remote from the user of
the instrument. The front cylinder terminates at its free end in a
point 12 which in the illustrated embodiment terminates in a
conically pointed configuration. Adjoining the front cylinder 10 is
a tubular outer conductor 20 which in its interior accommodates an
insulating hose or tube 30 through which extends a bar-shaped inner
conductor 40. At its distal end the bar-shaped inner conductor 40
has a male screwthread which can be screwed into a corresponding
female screwthread extending in the axial longitudinal direction
and is electrically and mechanically connected to the front
cylinder 10 by means of that screw connection 14.
[0078] Arranged between the front cylinder 10 and the outer
conductor 20 is an insulator element 50 which has a radial
partition 52 between the front cylinder 10 and the distal end wall
of the outer conductor 20 and the insulating tube 30. At the
outside on the partition 52 the insulator element 50 goes into a
casing wall 54 which--in the illustrated embodiment--surrounds the
outside surface of the front cylinder 10 in a condition of bearing
snugly thereagainst but which in an alternative
embodiment--directed towards the proximal end--can also surround
the outside surface of the outer conductor 20. The exposed outside
surface of the front cylinder 10 forms a first electrode 2. The
exposed outside surface of the outer conductor 20 forms a second
electrode 4. A high-frequency ac voltage source is connected to the
two electrodes--at the proximal end of the electrode
arrangement--when the bipolar electrode arrangement is introduced
into the human or animal tissue to be treated and the tissue is to
be coagulated by the thermal action of the electrical field.
[0079] FIG. 2 shows a second embodiment of the bipolar electrode
arrangement according to the invention, in which once again a front
cylinder 10 terminates in a conical distal tip 12, while again a
bar-shaped metal inner conductor is surrounded by an insulating
tube 30 which in turn is surrounded by a metal tubular outer
conductor 20. Provided between the front cylinder 10 and the end
wall of the outer conductor and the insulating tube 30 is an
insulator element 50 which is in the form of an annular body 58 and
which is of a predetermined axial length which holds the front
cylinder 10 and the outer conductor 20 at a spacing. The front
cylinder 10 comprises metal and serves as the cylindrical first
electrode 2. The outer conductor 20 is also made from metal and
serves as the cylindrical second electrode 4. The front cylinder 10
is connected to the inner conductor 40 by means of a screw
connection 14. Connected to the proximal end of the electrode
arrangement between the outer conductor 20 and the inner conductor
40 is an HF-ac voltage source if electrothermal coagulation of
surrounding tissue is to be effected.
[0080] FIG. 3 shows an embodiment, corresponding to FIGS. 1 and 2,
of a bipolar electrode arrangement in which the insulator element
50 is of a cup-shaped configuration, with the cylindrical casing
wall 54 being carried in a suitable annular opening 11 in the front
cylinder 10. In addition the radial partition 52 of the insulator
element 50 is passed in the direction of the proximal end in a
tubular configuration--at the diameter of the insulating tube 30--
against the insulating tube 30 which terminates a corresponding
axial length short of the distal end wall of the outer conductor
20.
[0081] FIG. 4 shows a fourth embodiment of a bipolar electrode
arrangement 1 according to the invention, which substantially
corresponds to the arrangement shown in FIG. 1, with the same parts
being denoted by the same references. In addition to the
arrangement shown in FIG. 1, extending centrally through the
bar-shaped inner conductor 14 and in aligned relationship therewith
and also through the front cylinder 10 is a hollow duct through
which passes an optical waveguide which passes visible light to the
distal tip 12 of the electrode arrangement when the optical
waveguide is proximally fed for example with visible laser light.
The optical waveguide 60 includes a sheath 62 surrounding the
light-conducting core 64. A cladding can also be provided around
the sheath 62.
[0082] FIG. 5 shows a further embodiment of the invention which
substantially corresponds to the embodiment of FIG. 4, but in which
the front cylinder 10 has a wedge-shaped tip 12 at its distal end.
Once again, extending through the inner conductor 40 and adjoining
same also through the front cylinder 10 is a central hollow duct
through which an optical waveguide 60 passes with its sheath 62 and
the core 64 to the distal tip 12 and optically indicates the
position of the distal tip 12 in the tissue for the user of the
electrode arrangement, in particular when treating tissue in
thin-walled parts of the body.
[0083] FIG. 6 shows a further embodiment of the bipolar electrode
arrangement 1 according to the invention, which substantially
corresponds to the embodiment of FIG. 2 or FIG. 4. Provided between
the front cylinder 10 and the concentric arrangement comprising the
outer conductor 20, the insulating tube 30 and the inner conductor
40 is an annular body 58 through which the inner conductor 40
axially extends to the front cylinder 10. The inner conductor 40
has a central hollow duct which extends as far as the distal end of
the annular body 58 and includes an optical waveguide 60. The
annular body 58 is formed from transparent or semitransparent
material and allows light to pass therethrough to the exterior.
Formed in the inner conductor into the core 64 of the optical
waveguide in the region of the annular body 58 are radial ground
incisions 42, with the consequence that light issues to the
exterior from those incisions radially from the inner conductor 40
and through the annular body 58 so that the position of the
electrical field which is produced between the first electrode 2
and the second electrode 4 when HF-power is applied to the inner
conductor 40 and the outer conductor 20 can be made optically
visible to the operator. Preferably, the annular body 58 is of such
a material or its surface is of such a structure that the light 3
issuing from the optical waveguide passes to the exterior in the
form of stray or scattered light.
[0084] FIGS. 7 and 8 show a further embodiment of the bipolar
electrode arrangement 1 according to the invention in longitudinal
section and in cross-section. Proximally adjoining a front cylinder
10 having a distal tip 12 is an elongate, electrically insulating
carrier 70 which--in the illustrated embodiment--is in the form of
a metal tube 71 with an externally disposed insulating layer 72.
For example the metal tube comprises titanium or a titanium alloy
and the insulating layer 72 is produced by anodization of the
surface of the tube 71 in the form of a thin ceramic layer. Applied
to the insulating layer 72 are two strip-shaped electrodes 2, 4
which extend parallel to each other in the longitudinal direction
of the carrier 70 and which--on the periphery of the insulating
layer, see FIG. 8--are disposed in mutually diametrally opposite
relationship. In the case of this electrode arrangement, an
electrical field is produced in the longitudinal direction of the
carrier, namely along the entire strip-shaped electrode 2, 4, so
that corresponding coagulation strips are also produced in the
longitudinal direction of the bipolar electrode arrangement when a
corresponding HF-ac voltage source is applied to the electrodes 2,
4.
[0085] FIGS. 9 and 10 show a further embodiment of a bipolar
electrode arrangement 1 for a surgical instrument according to the
invention, this embodiment representing a development of the
embodiment shown in FIGS. 7 and 8. An elongate, uniform, insulating
carrier 70 comprises a metal tube 71 which is completely coated
with an insulating layer 72 and which has continuously as far as
the distal tip 12 a central hollow duct through which an optical
waveguide 60 extends to the distal tip 12. The optical waveguide 60
comprises a light-conducting core 64 and a sheath 62 surrounding
the core. Disposed externally on the insulating layer 72 in the
longitudinal direction, that is to say in mutual parallel
relationship, are two strip-shaped electrodes 2, 4 which extend
over the entire illustrated length of the carrier 70 and which are
fixed on the insulating layer 72.
[0086] FIGS. 11 and 12 show a further embodiment of the invention
which substantially corresponds to the embodiment shown in FIGS. 9
and 10, but without using a tubular metal carrier 70. On the
contrary FIGS. 11 and 12 show an embodiment in which an optical
waveguide 60 with a core 64, a sheath 62 and a plastic cladding 61
is provided at its free end with a wedge-shaped tip 12 and which on
the sheath or cladding 61 in the longitudinal direction has two
strip-shaped electrodes 2, 4 which are arranged in mutually
opposite relationship at the periphery. In this embodiment the
electrodes 2, 4 are applied in the form of flexible layers so that
the entire bipolar electrode arrangement is flexible.
[0087] FIGS. 13 and 14 show views in cross-section of bipolar
electrode arrangements in which the carrier 70 is formed from
self-supporting metal bar profile members 76 extending in the
longitudinal direction. In FIG. 13 two bar profile members 76 of
metal are spaced in insulating relationship by spacer elements 60.
The bar profile members 76 are each approximately of a
cross-sectional configuration of a semicircular area and form
elongate electrodes 2, 4 which extend in the longitudinal direction
of the electrode arrangement. In the illustrated embodiment the
spacer elements 60 are in the form of optical waveguides 60.
Preferably fitted at the side surfaces are optical waveguides at
which light can also issue sideways so that, when using a bipolar
electrode arrangement of that kind, the operator can see along the
length of the electrodes 2 and 4 light signals which indicate the
position of the electrodes 2, 4 over the length thereof.
[0088] FIG. 14 shows an embodiment which corresponds to FIG. 13 and
in which two bar-shaped, self-supporting, metal bar profile members
76 which in cross-section are in the shape of portions of the wall
of a tube are applied to the outer cladding of an optical waveguide
in the longitudinal direction thereof and are secured in position
there and form the electrodes 2, 4. In the illustrated form the
optical waveguide 16 also has a sheath 62 between the outer
cladding 61 and the core 64.
[0089] FIGS. 15 and 16 show an embodiment of a bipolar electrode
arrangement in which a front cylinder 10 at the distal end of the
instrument is provided with a distal conical tip 12 which is
adjoined by an elongate, electrically insulating carrier 70. Two
tube portions 82, 84 are pushed on the carrier 70 spaced by way of
a spacer portion 83 of insulating material and secured in position
there, to form cylindrical electrodes 2, 4. Extending axially
through the carrier 70 is a central hollow duct 76 which
communicates with an opening 14 in the front cylinder 10 and
accommodates a temperature sensor 100 which is surrounded by a
plastic or adhesive bed 102 and is there fixed in position and by
way of a line 104 supplies a signal to the proximal end of the
instrument, corresponding to the temperature of the front cylinder
10. Also provided in the hollow duct 76 are connecting lines 90
which --through the carrier 70-- are connected to the electrodes 2,
4 and can be connected to the proximal HF-generator.
[0090] The axial length L1 of the first electrode 2 and the axial
length L2 of the second electrode 4-- in all the illustrated
embodiments--are greater than the spacing A between the two
electrodes 2, 4. The spacing A is preferably of the order of
magnitude of the outside diameter of the electrodes 2, 4. The
insulating portion 83 is of the same outside diameter D=2R as the
tube portions 82, 84 which form the electrodes 2, 4. R is the
radius of the electrode arrangement which is generally of a
circular-cylindrical configuration. In the embodiment shown in
FIGS. 15 and 16 in a particularly preferred case L1=L2.
[0091] FIG. 17 shows an embodiment of a bipolar electrode
arrangement in which a front cylinder 10 with a conical distal tip
12 is fixed to the end of a first tube portion 82, that first tube
portion 82 being secured with an end portion to a first carrier
70a. A second tube portion 84 is carried with an end portion on the
first carrier 70a and with its other end portion on a second
carrier 70b. The carriers 70a and 70b each have a respective hollow
duct 76, the axis of which aligns with the axis of the tube
portions 82, 84. The tube portions 82, 84 represent the cylindrical
electrodes 2, 4.
[0092] Extending through the hollow duct 76 of the carriers 70a and
70b and the tube portions 82, 84 is a flushing hoze or tube 110
which discharges fluid at its distal end, which then in contact
with the inside wall of the tube portions 82, 84 flows back through
the hollow duct 76 to the proximal end and cools the two tube
portions 82, 84. At the locations where the tube portions 82, 84
are pushed over the insulating carriers 70a, 70b and over the
insulating front cylinder 10 and glued fast in position at that
location, the tube portions 82, 84 are provided on their outside
surface with an annular insulating layer so that, at those
locations which are only cooled by the fluid to a lesser degree,
the electrode temperature does not experience an unwanted excessive
rise which results in the tissue being undesirably baked fast to
the electrodes or which results in the tissue bearing thereagainst
drying out and thus causes a rise in impedance in that tissue and
causes an interruption in the electrical current through the
tissue.
[0093] Cooling with a suitable cooling fluid affords the
consequence that the tissue at the contact surface with the
electrodes does not exceed a predetermined temperature and that the
coagulation hot-spot is some millimeters away from the
electrodes.
[0094] FIGS. 18 and 19 correspond to the embodiment of FIG. 17, but
the front cylinder 10 in FIGS. 18 and 19 comprises metal and goes
directly into the first tube portion 82, the first electrode, while
the front cylinder 10 in FIG. 19 is frontally rounded off. In a
particularly preferred embodiment the lengths L1 and L2 of the
electrodes 2, 4 are such that the surface area formed from the
front cylinder 10 and the first electrode is equal to or smaller
than the surface area of the second electrode.
[0095] FIG. 22 shows an embodiment of the bipolar electrode
arrangement which substantially corresponds to that shown in FIG.
17, but in which the second tube portion 84 which represents the
second electrode 4 is substantially longer than the first tube
portion 82 which represents the first electrode 2. In this
embodiment the second tube portion 84 terminates at the proximal
end of the instrument and it is therefore possible to omit a
further carrier at the proximal end of the instrument. The axial
length of the second electrode 4 is limited by virtue of the fact
that disposed on the proximal end portion of the second tube
portion 84 is an insulating layer 87 which covers over the metal
surface of the second tube portion 84 at that location, for example
with a ceramic coating. The field which produces thermoelectric
coagulation is then formed between the cylindrical metal electrodes
2, 4. In this embodiment also the end portions of the tube portions
82, 84 which on the inside are surrounded either by the insulating
material of the front cylinder 10 or the insulating material of the
carrier 70 are also coated with an insulating layer 86 on the
outside surface in order to prevent punctiform overheating of the
electrodes at those locations, because of the absence of
cooling.
[0096] FIG. 23 shows a further embodiment of the invention in which
a frontally rounded-off front cylinder 10 goes into a first tube
portion 82 which is fixed with its proximal end to an insulating
carrier. Provided at a predetermined spacing from the tube portion
82 on the insulating carrier is a metal layer 88. The tube 82 forms
the cylindrical first electrode 2, the metal coating on the carrier
70 forms the cylindrical second electrode 4. The carrier 70 and the
tube 82 are each provided with a central hollow duct 76 and 77
respectively through which a flushing hoze or tube 110 passes to a
position just short of the distal end of the front cylinder 10, for
discharging fluid at the distal end, the fluid cooling the first
electrode by coming into contact with the internal surface of the
first electrode 2. Disposed on the outside surface of the proximal
end portion of the tube 82 is an insulating layer 86 in order to
prevent local overheating of the electrode 2 at that location as
that location is not in contact at the inside with fluid. The front
cylinder 10 is formed from metal, its rounded configuration at the
distal end is advantageously suitable for the treatment of edge
tumors in which a layer of coagulated tissue is formed in front of
the distal end of the instrument.
[0097] FIGS. 20 and 21 show further embodiments of a bipolar
electrode arrangement. In both cases the basic structure provides a
front cylinder 10 of metal or insulating material, adjoined by a
tube 82 which is secured with the proximal end portion to a carrier
70. The carrier 70 and the tube 82 each have a respective central
hollow duct 76 and 77 respectively through which is passed a
flushing hoze or tube 110 which at its distal end discharges fluid
which then in contact with the inside surface of the tube 82 flows
back to the proximal end of the instrument. In FIG. 18 the distal
tube portion 82 has a metallic outside surface and forms the
cylindrical first electrode 2, the proximal tube portion 84
adjoining same is provided with an insulating layer 87 to which
there is applied at the proximal end a metal layer 88 forming the
cylindrical second electrode 4. In the embodiment of FIG. 19 in
contrast the distal tube portion 82 is provided with an insulating
layer 87 to which a metal layer 88 is applied at the distal end;
the metal layer 88 forms the first electrode. In this embodiment
the proximal tube portion forms the second electrode 4.
[0098] FIG. 24 shows a further embodiment of a bipolar electrode
arrangement in which a carrier 70 comprising a metal tube extends
to a wedge-shaped distal tip 12 and is in the shape of a cannula.
An insulating layer 87 is applied to the carrier 70 at a
predetermined spacing from the distal tip 12. In its proximal
region the insulating layer 87 is provided with a metal coating 88.
Adjoining the distal tip 12-- with a metal outside surface--is the
cylindrical first electrode 2 while the metal coating 88 at the
proximal region forms the cylindrical second electrode 4. Extending
through the tube is a hollow duct 76 which is open at the distal
end and which can serve for introducing medication.
[0099] FIGS. 25 and 26 show alternative forms of the embodiment
illustrated in FIG. 24. The embodiment of FIG. 25 differs from that
shown in FIG. 24 insofar as the insulating layer 87 applied to the
metal carrier 70 and the metal layer 88 applied to the insulating
layer 87 each have a respective distal edge which corresponds to
the wedge-shaped distal tip 12 of the carrier 70.
[0100] In the embodiment of FIG. 26, the carrier 70 is in the form
of a metal bar (instead of the tubular carrier 70 in FIG. 24) which
has a wedge-shaped distal tip and to which is applied the
insulating layer 87 on which the metal layer 88 is then
arranged.
[0101] All illustrated embodiments of the bipolar electrode
arrangement 1 are essentially of a circular cross-section of a
radius R and are of a cross-section which is as homogenous as
possible over their length. Irregularities in outside diameter are
to be minimised so that the electrode arrangement can be introduced
into the tissue with an easy sliding movement.
[0102] In all illustrated embodiments the axial length of the
electrodes is greater than the spacing of the electrodes which is
substantially of the order of magnitude of the outside diameter.
With this dimensioning, the arrangement affords advantageous local
concentration of the coagulation procedure and adequate strength in
terms of the electrical field involved. The carrier 70 can either
be of a flexible or a rigid nature.
[0103] In all embodiments in which a flushing hoze or tube
discharges flushing fluid at the distal end of a cavity, there is
the option of providing for temperature control of the electrodes
and the carrier before the electrode arrangement is introduced into
the body, that is to say heating same to over 30.degree. C. and
preferably 50.degree. C. In that way the electrode arrangement can
be more easily introduced into the tissue. As soon then as the
electrode arrangement has reached the treatment location and the
actual electrothermal treatment is to be initiated, then to achieve
an optimum coagulation procedure the instrument is cooled in order
to prevent the tissue from drying out at the electrodes and in
order to be able to apply higher levels of power and stronger
electrical fields without the tissue becoming baked fast to the
electrodes.
[0104] FIG. 27 shows a front cylinder 10 which comprises for
example aluminum or titanium or a titanium alloy and which by
anodic oxidation, that is to say in a proximal end region, was
provided with a ceramic layer forming the insulating element 50
whose partition 52 is formed at the proximal end of the front
cylinder and whose casing wall 58 extends on the outside around an
axial lengthwise portion of the front cylinder.
[0105] FIGS. 28 and 29 show an end portion, in the form of a spiral
spring 92, of a connecting line 90 which, as shown in FIG. 25, is
inserted into the hollow duct 77 of a metal tube 80 and bears under
radial contact pressure against the inside surface of the tube 80
and contacts same. An insulating layer 87 is illustrated on the
metal tube 80.
[0106] FIGS. 30 and 31 show longitudinal section views of two
embodiments of a bipolar electrode arrangement for a surgical
instrument where the instrument extends angled in the longitudinal
direction. Like parts have like reference numbers. FIGS. 30, 31
include lines 130, 131, respectively, indicating the instrument
angled in the longitudinal direction.
* * * * *