U.S. patent number RE36,795 [Application Number 08/724,997] was granted by the patent office on 2000-07-25 for surgical scissors with bipolar coagulation feature.
This patent grant is currently assigned to Everest Medical Corporation. Invention is credited to Mark A. Rydell.
United States Patent |
RE36,795 |
Rydell |
July 25, 2000 |
Surgical scissors with bipolar coagulation feature
Abstract
A bipolar electrosurgical scissors for use in open or endoscopic
surgery has a pair of opposed blade members pivotally joined to one
another and to the distal end of the scissors itself by a rivet
which extends through a insulated bushing member. Each of the blade
members comprises a blade support and a blade itself, each
fabricated from metal, such as stainless steel. The blades are
affixed to their associated supports by means of a suitable
adhesive or adhesive composite material such as a fiberglass
reinforced epoxy exhibiting dielectric properties. Cutting is
performed, steel-on-steel, without causing a short circuit between
the two blade supports which themselves function as the bipolar
electrodes.
Inventors: |
Rydell; Mark A. (Golden Valley,
MN) |
Assignee: |
Everest Medical Corporation
(Minneapolis, MN)
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Family
ID: |
22796036 |
Appl.
No.: |
08/724,997 |
Filed: |
October 3, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
213671 |
Mar 15, 1994 |
05352222 |
Oct 4, 1994 |
|
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Current U.S.
Class: |
606/45; 606/48;
606/50 |
Current CPC
Class: |
A61B
18/1445 (20130101); A61B 18/1402 (20130101); A61B
2017/0088 (20130101); A61B 2017/2945 (20130101); A61B
2018/1432 (20130101); A61B 2018/00107 (20130101); A61B
2018/126 (20130101); A61B 2018/1412 (20130101); A61B
2018/00083 (20130101) |
Current International
Class: |
A61B
18/18 (20060101); A61B 018/18 () |
Field of
Search: |
;606/41,42,45-52 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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517244 |
|
Dec 1992 |
|
EP |
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518230 |
|
Dec 1992 |
|
EP |
|
Primary Examiner: Peffley; Michael
Attorney, Agent or Firm: Nikolai, Mersereau & Dietz,
P.A.
Claims
What is claimed is:
1. A bipolar electrosurgical instrument for cutting and coagulating
tissue comprising:
(a) first and second blade members .[.each.]..Iadd., at least one
.Iaddend.comprising a laminated assembly of a metal blade defining
a shearing surface, a metal blade support and an intermediate
electrically insulative bonding/spacing layer for joining said
blade to said blade support;
(b) means for pivotally joining said first and second blade members
together with their respective shearing surfaces facing one
another;
(c) means coupled to .[.at least.]. one of said first and second
blade members for imparting a scissors-like movement relative to
the other of said first and second blade members; and
(d) means for applying a voltage between the metal blade supports
of said first and second blade members.
2. The bipolar electrosurgical instrument as in claim 1 wherein
said shearing surfaces of said first and second blade members and
said blade support are curved.
3. The bipolar electrosurgical instrument as in claim 2 wherein
said intermediate, electrically insulating bonding/spacing layer is
an epoxy material.
4. The bipolar electrosurgical instrument as in claim 3 wherein
said epoxy material includes a fiberglass-mat of a predetermined
thickness therein.
5. The bipolar electrosurgical instrument as in claim 3 wherein
said epoxy material includes glass microspheres of a predetermined
maximum diameter therein.
6. The bipolar electrosurgical instrument as in claim 3 wherein
said metal is stainless steel.
7. A bipolar electrosurgical instrument for cutting and coagulating
tissue comprising, in combination:
(a) an elongated tubular member having a proximal end, a distal end
and a lumen extending therebetween;
(b) first and second blade members, .[.each.]. .Iadd.at least one
.Iaddend.comprising a laminated assembly of a metal blade defining
a shearing surface, a metal blade support and an intermediate
electrically insulating spacing/bonding layer for joining said
blade to said blade support;
(c) means for pivotally joining said first and second blade members
to the distal end of said elongated tubular member with their
respective shearing surfaces facing one another;
(d) a handle affixed to said proximal end of said tubular
member;
(e) means coupled to said handle and extending through said lumen
for imparting a scissors-like movement to .[.at least.]. one of
said first and second blade members relative to the other; and
(f) means extending through said lumen for applying a voltage
between said blade supports of said first and second blade
members.
8. The bipolar electrosurgical instrument as in claim 7 wherein
said itnermediate electronically insulating bonding layer is an
epoxy material.
9. The bipolar electrosurgical instrument as in claim 8 wherein
said epoxy material includes a fiberglass-mat of a predetermined
thickness therein.
10. The bipolar electrosurgical instrument as in claim 8 wherein
said epoxy material includes glass microspheres of a predetermined
maximum diameter therein.
11. The bipolar electrosurgical instrument as in claim 7 wherein
said first and second blade members are curved. .Iadd.
12. A bipolar electrosurgical instrument for cutting and
coagulating tissue comprising:
(a) first and second blade members each comprising a laminated
assembly of a metal blade defining a shearing surface, a metal
blade support and an intermediate electrically insulative
bonding/spacing layer for joining said blade to said blade
support;
(b) means for pivotally joining said first and second blade members
together with their respective shearing surfaces facing one
another;
(c) means coupled to at least one of said first and second blade
members for imparting a scissor-like movement relative to the other
of said first and second blade members; and
(d) means for applying a voltage between the metal blade supports
of said first and second blade members..Iaddend..Iadd.13. A bipolar
electrosurgical instrument for cutting and coagulating tissue
comprising, in combination:
(a) an elongated tubular member having a proximal end, a distal end
and a lumen extending therebetween;
(b) first and second blade members, each comprising a laminated
assembly of a metal blade defining a shearing surface, a metal
blade support and an intermediate electrically insulating
spacing/bonding layer for joining said blade to said blade
support;
(c) means for pivotally joining said first and second blade members
to the distal end of said elongated tubular member with their
respective shearing surfaces facing one another;
(d) a handle affixed to said proximal end of said tubular
member;
(e) means coupled to said handle and extending through said lumen
for imparting a scissor-like movement to at least one of said first
and second blade members relative to the other; and
(f) means extending through said lumen for applying to a voltage
between said blade supports of said first and second blade
members..Iaddend..Iadd.14. A bipolar electrosurgical instrument for
cutting and coagulating tissue, comprising:
(a) first and second blade members each having an inner shearing
surface and a conductive portion, at least one of said blade
members comprising a laminated assembly of an inner metal blade
defining said inner shearing surface, an intermediate electrically
insulative layer, and an outer metal conductive layer forming said
conductive portion which is electrically insulated from said inner
metal blade by said intermediate electrically insulative layer;
(b) means for pivotally joining said first and second blade members
with their respective inner shearing surfaces facing one
another;
(c) means coupled to at least one of said first and second blade
members for imparting a scissors-like movement relative to the
other of said first and second blade members; and
(d) means for applying a voltage between said conductive portions
of said
first and second blade members..Iaddend..Iadd.15. An endoscopic
scissors blade for use in a bipolar endoscopic instrument, said
blade comprising:
(a) an inner metal shearing surface;
(b) an intermediate electrically insulative layer;
(c) an outer metal conductive layer which is electrically insulated
from said inner metal shearing surface by said intermediate
electrically insulative layer; and
(d) means for coupling a source of voltage to said outer metal
conductive layer..Iaddend..Iadd.16. An endoscopic scissors blade
according to claim 15, further comprising:
(e) means for pivotally mounting said scissors blade; and
(f) means for coupling said scissors blade to a means for imparting
a
pivotal movement to said scissors blade..Iaddend..Iadd.17. An
endoscopic scissors blade according to claim 15, wherein:
said intermediate electrically insulative layer is a fiberglass
blade support and said inner metal shearing surface and said outer
metal conductive layer are laminated layers on said fiberglass
blade
support..Iaddend..Iadd.18. A bipolar electrosurgical scissors
comprising:
(a) a pair of blades, at least one blade of the pair having
(i) an inner metal shearing surface;
(ii) an intermediate electrically insulative layer;
(iii) an outer metal conductive layer which is electrically
insulated from said inner metal shearing surface by said
intermediate electrically insulative layer; and
(b) means for coupling a source of voltage to said outer metal
conductive layer..Iaddend..Iadd.19. A bipolar electrosurgical
scissors according to claim 18, further comprising:
(e) means for pivotally mounting said pair of blades; and
(f) means for coupling one of said scissors blade to a means for
imparting a pivotal movement to said scissors
blade..Iaddend..Iadd.20. A bipolar electrosurgical scissors
according to claim 18, wherein:
said intermediate electrically insulative layer is a fiberglass
blade support and said inner metal shearing surface and said outer
metal conductive layer are laminated layers on said fiberglass
blade support..Iaddend..Iadd.21. A bipolar electrosurgical
instrument for cutting and coagulating tissue, comprising:
(a) first and second blade members each comprising a laminated
assembly of a metal blade defining a shearing surface, an
intermediate electrically insulative layer, and a metal blade
support which is electrically insulated from said metal blade by
said intermediate electrically insulative layer;
(b) means for pivotally joining said first and second blade members
together with their respective shearing surfaces facing one
another;
(c) means coupled to at least one of said first and second blade
members
for imparting a scissor-like movement relative to the others of
said first and second blade members; and
(d) means for applying a voltage between the metal blade supports
of said first and second blade members..Iaddend..Iadd.22. A bipolar
electrosurgical instrument according to claim 21, wherein:
said shearing surfaces of said first and second blade members and
said blade support are curved..Iaddend..Iadd.23. A bipolar
electrosurgical instrument according to claim 22, wherein:
said metal is stainless steel..Iaddend..Iadd.24. A bipolar
electrosurgical instrument for cutting and coagulating tissue,
comprising, in combination:
(a) an elongated tubular member having a proximal end, a distal
end, and a lumen extending therebetween;
(b) first and second blade members, each comprising a laminated
assembly of a metal blade defining an inner shearing surface, an
intermediate electrically insulative layer, and a metal blade
support which is electrically insulated from said metal blade by
said intermediate electrically insulative layer;
(c) means for pivotally joining said first and second blade members
together with their respective shearing surfaces facing one
another;
(d) a handle affixed to said proximal end of said tubular
member;
(e) means coupled to said handle and extending through said lumen
for imparting a scissor-like movement to at least one of said first
and second blade members relative to the other; and
(f) means extending through said lumen for applying a voltage
between said blade supports of said first and second blade
members..Iaddend..Iadd.25. A bipolar electrosurgical instrument
according to claim 24 wherein:
said inner shearing surfaces of said first and second blade members
are
curved..Iaddend..Iadd.26. A bipolar electrosurgical instrument
according to claim 24, wherein:
said metal is stainless steel..Iaddend..Iadd.27. A bipolar
electrosurgical instrument for cutting and coagulating tissue,
comprising, in combination:
(a) an elongated tubular member having a proximal end, a distal
end, and a lumen extending therebetween;
(b) first and second blade members each having an inner shearing
surface and a conductive portion, at least one of said blade
members comprising a laminated assembly of an inner metal blade
defining said inner shearing surface, an intermediate electrically
insulative layer, and an outer metal conductive layer forming said
conductive portion which is electrically insulated from said inner
metal blade by said intermediate electrically insulative layer;
(c) means for pivotally joining said first and second blade members
with their respective inner shearing surfaces facing one
another;
(d) a handle affixed to said proximal end of said tubular
member;
(e) means coupled to said handle and extending through said lumen
for imparting a scissor-like movement to at least one of said first
and second blade members relative to the other; and
(f) means extending through said lumen for applying a voltage
between said conductive portions of said first and second blade
members..Iaddend..Iadd. 8. A bipolar electrosurgical instrument
according to claim 27, wherein:
each of said first and second blade members comprises a laminated
assembly of an inner metal blade defining said inner shearing
surface, an intermediate electrically insulative layer, and an
outer metal conductive layer forming said conductive portion which
is electrically insulated from said inner metal blade by said
intermediate electrically insulative layer..Iaddend..Iadd.29. A
bipolar electrosurgical scissors comprising:
(a) first and second blade members each comprising an assembly of a
metal shearing surface, an electrically conductive electrode, and
an intermediate electrically insulative material disposed between
and fixed to the metal shearing surface and the electrically
conductive electrode;
(b) means coupled to at least one of said first and second blade
members for imparting scissor-like movement relative to the other
of said first and second blade members; and
(c) means for applying a voltage between the electrically
conductive electrodes of said first and second blade
members..Iaddend..Iadd.30. A bipolar electrosurgical scissors
according to claim 29, wherein:
said metal shearing surfaces of said first and second blade members
are curved..Iaddend..Iadd.31. A bipolar electrosurgical scissors
according to claim 30, wherein:
said intermediate, electrically insulative material is an epoxy
material..Iaddend..Iadd.32. A bipolar electrosurgical scissors
according to claim 31, wherein:
said epoxy material includes a fiberglass-mat of a predetermined
thickness therein..Iaddend..Iadd.33. A bipolar electrosurgical
scissors according to claim 31 wherein:
at least one of said metal shearing surface and said
electrically
conductive electrode is made of stainless steel..Iaddend..Iadd.34.
A bipolar electrosurgical scissors comprising:
(a) first and second blade members each comprising an assembly of a
metal shearing surface, an electrically conductive electrode, and
an intermediate electrically insulative layer disposed between and
affixed to the metal shearing surface and the electrically
conductive electrode, at least one of said first and second blade
members having a pivot hole for mounting it relative to the other
of said first and second blade members to allow a scissor-like
movement of said at least one of said first and second blade
members relative to the other of said first and second blade
members;
(b) a reciprocating member coupled to said at least one of said
first and second blade members and importing scissor-like movement
to said at least one of said first and second blade members
relative to the other of said first and second blade members;
and
(c) first and second electrically conductive members coupled to
respective electrically conductive electrodes and applying a
voltage between the electrically conductive electrodes of said
first and second blade members..Iaddend..Iadd.35. A bipolar
electrosurgical scissors according to claim 34, wherein:
said metal shearing surfaces of said first and second blade members
are
curved..Iaddend..Iadd.36. A bipolar electrosurgical scissors
according to claim 35, wherein:
said intermediate, electrically insulative layer is an epoxy
material layer..Iaddend..Iadd.37. A bipolar electrosurgical
scissors according to claim 36, wherein:
said epoxy material includes a fiberglass-mat of a predetermined
thickness therein..Iaddend..Iadd.38. A bipolar electrosurgical
scissors according to claim 36, wherein:
at least one of said metal shearing surface and said electrically
conductive electrode is made of stainless steel..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the design of a bipolar
electrosurgical scissors, and more particularly to a surgical
scissors incorporating bipolar electrodes as its blade elements,
such that mechanical cutting with subsequent electrocoagulation can
be achieved without requiring an instrument exchange.
2. Discussion of the Prior Art
Electrocoagulating instruments include at least one conductive
electrode. Radio frequency energy is conducted through this
electrode to either a remote conductive body-plate (monopolar) or
to a second, closely-spaced conductive electrode (bipolar). Current
passing through the gap between the two electrodes will coagulate
blood and other body fluids placed between them.
Monopolar electrocautery instruments suffer from the fact that the
return path between the active-electrode and the large area
body-plate can be unpredictable as the electrical current seeks the
return electrode through the path of least resistance. With bipolar
electrosurgical instruments, however, because the two electrodes
are closely spaced to one another, usually at the distal end of an
instrument handle, the return path is very short and only involves
the tissue and fluids in the short path between the electrodes.
There is available in the prior art a scissors-type instrument for
mechanically snipping tissue during the course of an endoscopic
procedure. Such a scissors comprises of pair of blades fabricated
from metal and disposed at the distal end of an elongated tubular
member whose outside diameter is sufficiently small to allow it to
be passed through the working lumen of an endoscope, a laparoscope
or other similar devices known in the art. Disposed at the proximal
end of the rigid tube is a scissors-type handle having a pair of
members, each with a finger-receiving loop therein which are
pivotally coupled to one another. An appropriate linkage is made
between the handle members and the blades so that manipulation of
the handle members will result in an opening and closing of the
blades relative to one another. When using a mechanical cutting
scissors of this type to excise tissue, when a blood vessel is cut,
bleeding results. At that point, it is generally necessary for the
surgeon to remove the scissors instrument from the working lumen of
the endoscope and then insert an electrocoagulator down the
endoscope to the site of the bleeder. This instrument exchange is
time-consuming and in a surgical procedure where moments count, it
would be desirable to have a scissors-type instrument for cutting
but which also incorporates the ability to coagulate blood and
other body tissue using RF energy.
There is also available in the prior art monopolar scissors where
both of the scissors blades form one pole and with a remote body
plate being the second pole. To date, however, there is not
available in the marketplace a bipolar electrosurgical scissors
where its two blades are electrically isolated from one another and
comprise the bipolar electrode pair. With metal-to-metal contact
along the sharpened edges of the two blades, an electrical short
results. Furthermore, the attempt to use a rivet or screw as the
pivot point for the blades is another area where short-circuiting
is likely to occur. When such a short exists, the electrical
current does not flow through the blood or body tissue to effect
coagulation, but instead, follows the short-circuit path from one
electrode to the other.
In a copending application, Ser. No. 07/887,212, filed May 26,
1992, there is described a bipolar scissors for insertion into a
laparoscope, trocar or endoscope for effecting electrocoagulation
of blood and tissue during laparoscopic or other endoscopic
surgery. The scissors blades at the distal tip of the instrument
perform cutting of the tissue by mechanical shearing action. The
two blades are effectively insulated from one another, allowing
them to function as bipolar electrodes for electrocoagulating small
blood vessels in the surgical field.
The instrument of the aforereferenced application includes a
scissors-type handle having first and second pivoting members, each
with a finger-receiving loop on one end of each and extending from
the opposite end of one is an elongated, rigid tubular member of a
size capable of being inserted through the trocar or endoscope.
Affixed to the distal end of the rigid tubular member is a first
blade composite which comprises a metal blank having a suitable
ceramic layer bonded to one major surface thereof, the ceramic
being honed to define a sharp cutting edge. Pivotally joined to the
first blade by an insulating pivot member is a second blade
composite, also having a metal blank with a ceramic substrate
bonded to one major surface thereof. When the two blade blanks are
pivotally joined together, the ceramic layers are in face-to-face
relationship and because the cutting edges thereof are honed, the
blades are capable of cutting tissue when made to move in a
scissors-like manner with tissue placed between the cutting edges
thereof.
Extending through the lumen of the elongated tubular member is a
wire or rod which is rigid in the longitudinal direction and which
is coupled at its proximal end to one of the handle members and at
its other end to one of the scissors blades. By appropriately
manipulating the handle members, a snipping action of the blades
results.
The instrument further includes means for applying a RF voltage
across the gap between the two metal blade blanks which are
maintained separated from one another by the ceramic faces bonded
to these blanks. As such, the blades of the instrument itself can
be used as a bipolar electrocoagulation device, obviating the need
for doing an instrument exchange when it is necessary to coagulate
blood and tissue following the mechanical cutting thereof.
In copending application Ser. No. 08/092,076, filed Jul. 16, 1993,
there is described a bipolar electrosurgical scissors having curved
blades in the embodiments of each of the aforereferenced
applications, the bipolar blades are constructed by appropriately
adhering a specially ground ceramic insulating member defining the
sheering surface and cutting edge of the scissors to metal
electrodes where it is the ceramic surfaces that interact with one
another to perform the cutting function as the blades are opened
and closed relative to one another. While that arrangement works
well in implementing a bipolar electrosurgical scissors, the cost
of manufacture is relatively high because of the difficulty in
working with ceramics, especially when constructing electrosurgical
scissors having arcuate blades. Those skilled in the art appreciate
that ceramic will readily fracture when subjected to bending forces
and, hence, it is necessary to produce the requisite ceramic
elements for the scissors in a series of grinding operations.
A need therefore exists for a bipolar electrosurgical scissors for
use in both open and endoscopic surgical procedures where the
shearing surfaces may be surgical steel, but where the blades can
also be used in performing bipolar electrocoagulation as the
cutting progresses.
SUMMARY OF THE INVENTION
It is accordingly a principal object of the present invention to
provide a bipolar, electrocoagulating instrument having metal
scissors blades for the mechanical cutting of tissue.
Another object of the present invention is to provide a pair of
bipolar scissors having a miniaturized distal blade configuration
that allows the instrument to be inserted through a laparoscope,
trocar or the working lumen of an endoscope.
Still another object of the present invention is to provide a
bipolar-type scissors instrument having metal (stainless steel)
cutting surfaces and which utilizes a push rod and pivot
combination to cause movement of the scissors blade through
manipulation of a scissors-style handle mechanism at the proximal
end of the instrument and wherein blade supports for the scissors
may be simultaneously energized from a RF source to effect the
electrocoagulation of cut tissue.
The foregoing object of the invention is achieved by providing an
instrument having a metal blade member with a sheering surface and
a honed cutting edge. The blade member is affixed to a metal blade
support by an electrically insulating bonding layer which is
disposed intermediate the blade member and the blade support. In
forming an endoscopic scissors, this blade assembly is pivotally
secured to the distal end of an elongated tube. An actuating link
extends through the tube to a movable portion of a scissors handle
so that when the handle is manipulated, the blades can be made to
open and close relative to one another in scissors-like fashion.
Also extending through the lumen from electrical terminals on the
handle to the metal blade supports are conductors which permit a
voltage to be applied between the two blade supports. Because the
blade having the sharpened edge and shearing surface is insulated
from its blade support, there will be no short circuit between the
blade members due to the fact that the conductive shearing surfaces
come into contact with one another along their length as the blades
are closed on an object to be cut.
It has been found convenient in the manufacture of the scissors of
the present invention to employ a partially cured epoxy, an epoxy
impregnated fiberglass mat or a slurry of glass beads and epoxy as
the bonding layer for joining the blades to their respective
supports while maintaining a desired spacing therebetween. The
partially cured epoxy can be die-cut to size so as to conform in
shape to the interface between the blade support and the blade
member. When the laminated structure is clamped together and then
subjected to a heating operation, the epoxy spacer layer fully
cures and creates a strong bond between the blade and its blade
support, while still maintaining electrical isolation
therebetween.
DESCRIPTION OF THE DRAWINGS
The foregoing features, objects and advantages of the invention
will become apparent to those skilled in the art from the following
detailed description of a preferred embodiment, especially when
considered in conjunction with the accompanying drawings in which
like numerals in the several views refer to corresponding
parts.
FIG. 1 is a perspective view of an endoscopic electrosurgical
scissors constructed in accordance with the present invention;
and
FIG. 2 is a greatly enlarged top view of the distal end portion of
the scissors of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is indicated generally by numeral 10 a
bipolar electrosurgical scissors for endoscopic surgery constructed
in accordance with the present invention. It is seen to include an
elongated tubular barrel 12 having a proximal end 14, a distal end
16 and with a lumen extending therebetween. The O.D. of the barrel
is sufficiently small to be passed through the working lumen of an
endoscope (laparoscope). Affixed to the proximal end 14 of the
bipolar scissors 10 is a rotatable knob 18 appropriately mounted in
the stationary portion 20 of a scissors handle assembly 22 so that
the knob 18 can be rotated, the barrel 12 turning with it. Those
desiring further details on the construction and internal workings
of the handle assembly 22 are referred to applicant's earlier
patent application Ser. No. 08/013,852, filed Feb. 5, 1993. That
application describes in detail how manipulation of the scissors
handle 22 causes blades 24 and 26 connected to the distal end 16 of
the tube 12 to move in scissors-like action relative to one
another. Because the novel
features of the present invention center on the construction of the
blades 24 and 26, there is no need to further describe the details
of the handle construction.
Referring to FIG. 2, there is shown a greatly enlarged top plan
view of the distal end portion of the scissors viewed along the
line 2--2 in FIG. 1. Blade 24 is seen to comprise a conductive
metal blade support 28, preferably fabricated from stainless steel.
While the blade support 28 is illustrated as having an arcuate
profile when observed from the top as in FIG. 2, it can just as
well be straight. Attached to the blade support by means of a
dielectric bonding agent 30 is a metal blade 32 having an arcuate
shearing surface 34 and a honed cutting edge.
In adhering the cutting blade 34 to the blade support 28, it has
been found convenient to employ a suitable epoxy, such as AF 125
sold by the 3M Company because of its desired dielectric
characteristics. The epoxy bonding/spacing layer 30 may be obtained
in a partially cured state so that it is rigid enough to hold its
own shape, but can easily be die-cut to a desired size and shape
characteristic. The partially cured epoxy layer is then applied
against the concave surface of the blade support 28 and because in
the partially cured state, the material is tacky, it will adhere to
it. Next, the blade 34, itself, is pressed against the other side
of the partially cured epoxy bonding layer 30 and when
appropriately aligned, a suitable clamp is used to hold the
assembly together. The assembly may then be placed in an oven or
otherwise heated to the point where the epoxy layer becomes fully
cured and hard. When the assembly is removed from the oven and the
clamp is removed, it is found that a very strong bond holds the
blade 34 to the support 28. The two are electrically insulated from
one another, however, by the epoxy bonding layer.
To ensure that clamping and heating does not alter the width of the
insulating gap, a fiberglass mat of the desired thickness can be
impregnated with a B-stage type epoxy or glass beads of a diameter
corresponding to the desired gap width can be mixed with the
B-stage epoxy before it is interposed between the blade and its
support and prior to the clamping and heat curing thereof.
The other scissors blade 26 is manufactured in much the same
fashion. It includes a blade support 36 and a blade member 38
bonded together by a dielectric bonding/spacing layer 40. The
dielectric bonding/spacing layer is again preferably an epoxy or a
glass-filled epoxy material adhered to the convex surface of the
blade support 36.
The proximal end portions 42 and 44 of the blade supports 28 and 36
each have a circular aperture extending therethrough as at 46 and
fitted into each of the apertures is an insulating bushing half
48-50 allowing a steel rivet 52 to pivotally secure the blades 24
and 26 to an insulating hub 54 without creating an electrical short
circuit between the blade supports 28 and 36. The hub member 54
fits within the distal end 16 of the tubular barrel 12 and is
appropriately bonded or swagged so as not to come loose.
The mechanism for actuating the blades 24 and 26 in a scissors-like
motion is similar to that described in applicant's earlier
copending application Ser. No. 08/013,852, which is herein
incorporated by reference. In that arrangement, first and second
conductive rods 56 and 58 extend through the lumen of the barrel 12
from the scissors handle members to a pair of conductive links 60
and 62. The links are pivotally secured to the distal ends of the
rods 58 and 60 and to the blade halves 24 and 26 by means of
conductive metal rivets 64 and 66. The rivets 64 and 66 pass
through apertures formed in the distal end portions of the blade
halves 24 and 26 at locations that are off of center so that a
lever arm is created for moving the blades as the conductive rods
56 and 58 are reciprocally, longitudinally displaced by actuation
of the scissors handle 22. A slip-ring connection is provided in
the handle portion 20 for allowing conductors in the insulated
electrical cord 68 (FIG. 1) to join to the conductive rods 56 and
58 while still permitting the barrel 12 to be rotated upon turning
the knob 18 and without twisting the conductors in lead 68. In this
fashion, a predetermined RF voltage may be applied across the blade
supports 28 and 36 by way of the lead 68, the conductive rods 56
and 58, the links 60 and 62 and the rivets 64 and 66. Because of
the insulating layers 30 and 40 used in bonding the sharpened
blades 32 and 38 to the blade supports 28 and 36, those two blades
can touch one another along their entire length as the cutting
motion takes place without creating an electrical short circuit
therebetween. When it is desired to cauterize tissue, the RF
voltage is applied to the electrosurgical scissors, thereby making
the blade supports the active bipolar electrodes. When the two
blade supports are brought into contact with tissue, a current
flows from the first blade support, through the tissue to the
second blade support, thereby effecting cauterization.
The present invention obviates the need for providing a somewhat
fragile ceramic layer to define the shearing surface and cutting
edges of the blades. The stainless steel blade supports and the
blades themselves can be readily bent to create a curved blade
without the need for expensive grinding operations heretofore
necessary in creating curved ceramic pieces.
The use of a partially cured epoxy dielectric adhesive in the early
stages of fabrication for adhering the blade to its support and
then later fully curing the epoxy layer also greatly simplifies the
steps needed to manufacture an electrosurgical scissors having
bipolar electrodes.
This invention has been described herein in considerable detail in
order to comply with the Patent Statutes and to provide those
skilled in the art with the information needed to apply the novel
principles and to construct and use such specialized components as
are required. However, it is to be understood that the invention
can be carried out by specifically different equipment and devices,
and that various modifications, both as to the equipment details
and operating procedures, can be accomplished without departing
from the scope of the invention itself. For example, while an
endoscopic scissors has been used in explaining the invention, it
is equally applicable to a scissors designed for open surgery.
Hence, the scope of the invention is to be determined from the
appended claims.
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