U.S. patent application number 13/633554 was filed with the patent office on 2013-01-31 for single action tissue sealer.
This patent application is currently assigned to COVIDIEN AG. The applicant listed for this patent is COVIDIEN AG. Invention is credited to Sean T. Dycus, David M. Garrison, Paul Hermes.
Application Number | 20130030432 13/633554 |
Document ID | / |
Family ID | 37768171 |
Filed Date | 2013-01-31 |
United States Patent
Application |
20130030432 |
Kind Code |
A1 |
Garrison; David M. ; et
al. |
January 31, 2013 |
Single Action Tissue Sealer
Abstract
An endoscopic bipolar forceps includes a housing and a shaft,
the shaft having an end effector assembly at its distal end. The
end effector assembly includes two jaw members for grasping tissue
therebetween. The jaw members are adapted to connect to an
electrosurgical energy source which enable them to conduct energy
through the tissue to create a tissue seal. A drive assembly is
disposed within the housing which moves the jaw members. A switch
is disposed within the housing which activates the electrosurgical
energy. A knife assembly is included which is advanceable to cut
tissue held between the jaw members. A movable handle is connected
to the housing. Continual actuation of the movable handle engages
the drive assembly to move the jaw members, engages the switch to
activate the electrosurgical energy source to seal the tissue, and
advances the knife assembly the cut the tissue disposed between the
jaw members.
Inventors: |
Garrison; David M.;
(Longmont, CO) ; Hermes; Paul; (Guilford, CT)
; Dycus; Sean T.; (Zurich, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
COVIDIEN AG; |
Neuhausen am Rheinfall |
|
CH |
|
|
Assignee: |
COVIDIEN AG
Neuhausen am Rheinfall
CH
|
Family ID: |
37768171 |
Appl. No.: |
13/633554 |
Filed: |
October 2, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12621056 |
Nov 18, 2009 |
8277447 |
|
|
13633554 |
|
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|
|
11207956 |
Aug 19, 2005 |
7628791 |
|
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12621056 |
|
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Current U.S.
Class: |
606/42 ;
606/48 |
Current CPC
Class: |
A61B 17/32 20130101;
A61B 17/282 20130101; A61B 17/3205 20130101; A61B 18/18 20130101;
A61B 17/320016 20130101; A61B 2018/00589 20130101; A61B 2018/1412
20130101; A61B 2018/1455 20130101; A61B 18/085 20130101; A61B 18/00
20130101; A61B 18/1445 20130101; A61B 2018/0063 20130101; A61B
2018/00404 20130101; A61B 2018/00601 20130101; A61B 2090/08021
20160201; A61B 2018/00922 20130101; A61B 2018/00595 20130101; A61B
2018/126 20130101; A61B 17/285 20130101; A61B 2018/00702 20130101;
A61B 18/1206 20130101; A61B 2018/00916 20130101; A61B 2017/2946
20130101 |
Class at
Publication: |
606/42 ;
606/48 |
International
Class: |
A61B 18/18 20060101
A61B018/18 |
Claims
1. A bipolar forceps, comprising: a housing; an elongated member
extending distally from the housing and defining a longitudinal
axis; an end effector assembly disposed adjacent a distal end of
the elongated member, the end effector assembly including a first
jaw member and a second jaw member, the first jaw member moveable
relative to the second jaw member from a first position in spaced
relation to the second jaw member to a second position closer to
the second jaw member for grasping tissue therebetween, at least
one of the jaw members adapted to connect to an electrosurgical
energy source such that the jaw members are capable of conducting
energy through tissue grasped therebetween to effect a tissue seal;
a drive assembly operably coupled to the housing for moving the
first jaw member from the first position to the second position; a
knife assembly configured to cut tissue disposed between the jaw
members; and a movable handle connected to the housing and
selectively rotatable about a pivot, wherein a single, continuous
actuation of the movable handle is operable to engage the drive
assembly to move the first jaw member and to advance the knife
assembly to cut tissue disposed between the jaw members; wherein
the knife assembly is prevented from being advanced to cut tissue
prior to the first jaw member being moved toward its second
position.
2. A bipolar forceps according to claim 1, wherein each of the jaw
members includes a longitudinally-extending knife channel extending
at least partially therethrough.
3. A bipolar forceps according to claim 1, wherein at least one of
the jaw members includes at least one stop member disposed thereon
that regulates the distance between the jaw members.
4. A bipolar forceps according to claim 3, wherein the distance
between the jaw members is between 0.001 inches and 0.006
inches.
5. A bipolar forceps according to claim 1, wherein a pressure range
between the jaw members when disposed in the second position is
between about 3 kg/cm.sup.2 and about 16 kg/cm.sup.2.
6. A bipolar forceps according to claim 1, further including at
least one tactile element that provides tactile feedback to a user
relating to at least one of tissue sealing and tissue cutting.
7. A bipolar forceps according to claim 1, further including a
switch operably coupled to the housing and configured to activate
the electrosurgical energy source.
8. A bipolar forceps, comprising: a housing; an elongated member
extending distally from the housing and defining a longitudinal
axis; an end effector assembly disposed adjacent a distal end of
the elongated member, the end effector assembly including a first
jaw member and a second jaw member, the first jaw member being
moveable relative to the second jaw member from a first position in
spaced relation to the second jaw member to a second position
closer to the second jaw member for grasping tissue therebetween; a
drive assembly operably coupled to the housing for moving the first
jaw member from the first position to the second position; a knife
assembly configured to cut tissue disposed between the jaw members;
and a movable handle connected to the housing and selectively
rotatable about a pivot, wherein a single actuation of the movable
handle is operable to engage the drive assembly to move the first
jaw member and to advance the knife assembly to cut tissue disposed
between the jaw members; wherein the knife assembly is prevented
from being advanced to cut tissue prior to the first jaw member
being moved toward its second position, and wherein the movable
handle is the only user actuatable feature that effects the ability
to advance the knife assembly.
9. A bipolar forceps according to claim 8, wherein each of the jaw
members includes a longitudinally-extending knife channel extending
at least partially therethrough.
10. A bipolar forceps according to claim 8, wherein at least one of
the jaw members includes at least one stop member disposed thereon
that regulates the distance between the jaw members.
11. A bipolar forceps according to claim 10, wherein the distance
between the jaw members is between 0.001 inches and 0.006
inches.
12. A bipolar forceps according to claim 8, wherein a pressure
range between the jaw members when disposed in the second position
is between about 3 kg/cm.sup.2 and about 16 kg/cm.sup.2.
13. A bipolar forceps according to claim 8, further including at
least one tactile element that provides tactile feedback to a user
relating to at least one of tissue sealing and tissue cutting.
14. A bipolar forceps according to claim 8, wherein at least one of
the jaw members is adapted to connect to an electrosurgical energy
source such that the jaw members are capable of conducting energy
through tissue grasped therebetween to effect a tissue seal.
15. A method for using a bipolar forceps to grasp and cut tissue,
the method comprising: providing a bipolar forceps, the forceps
having a housing, a shaft extending from the housing, and an end
effector assembly disposed adjacent a distal end thereof, the end
effector assembly including a first jaw member and a second jaw
member, a drive assembly operably coupled to the housing, a knife
assembly, and a movable handle connected to the housing and
selectively rotatable about a pivot; with a single, continuous
actuation of the movable handle, engaging the drive assembly to
move the first jaw member toward the second jaw member such that
the first and second jaw members grasp tissue therebetween, and
advancing at least a portion of the knife assembly to cut tissue
disposed between the jaw members; and wherein the knife assembly is
prevented from being advanced to cut tissue prior to the first jaw
member being moved toward the second jaw member.
16. A method for using a bipolar forceps to grasp and cut tissue of
claim 15 wherein the movable handle is the only user actuatable
feature that effects the ability to advance the knife assembly.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Continuation of U.S. Pat. No.
8,277,447, which was filed on Nov. 18, 2009, which is a
Continuation of U.S. Pat. No. 7,628,791, which was filed on Aug.
19, 2005, the entire contents of each of which are hereby
incorporated by reference herein.
BACKGROUND
[0002] The present disclosure relates to an electrosurgical forceps
and more particularly, the present disclosure relates to an
endoscopic bipolar electrosurgical forceps for manipulating,
clamping, sealing and cutting tissue in a single action.
TECHNICAL FIELD
[0003] Electrosurgical forceps utilize both mechanical clamping
action and electrical energy to affect hemostasis by heating the
tissue and blood vessels to coagulate, cauterize and/or seal
tissue. As an alternative to open forceps for use with open
surgical procedures, many modern surgeons use endoscopes and
endoscopic instruments for remotely accessing organs through
smaller, puncture-like incisions. As a direct result thereof,
patients tend to benefit from less scarring and reduced healing
time.
[0004] Endoscopic instruments are inserted into the patient through
a cannula, or port, which has been made with a trocar. Typical
sizes for cannulas range from about three millimeters to about 12
millimeters. Smaller cannulas are usually preferred, which, as can
be appreciated, ultimately presents a design challenge to
instrument manufacturers who look for ways to make endoscopic
instruments that fit through the smaller cannulas.
[0005] Many endoscopic surgical procedures require cutting or
ligating blood vessels or vascular tissue. Due to the inherent
spatial considerations of the surgical cavity, surgeons often have
difficulty suturing vessels or performing other traditional methods
of controlling bleeding, e.g., clamping and/or tying-off transected
blood vessels. By utilizing an endoscopic electrosurgical forceps,
a surgeon can either cauterize, coagulate/desiccate and/or simply
reduce or slow bleeding simply by controlling the intensity,
frequency and duration of the electrosurgical energy applied
through the jaw members to the tissue. Most small blood vessels,
i.e., in the range below two millimeters in diameter, can often be
closed using standard electrosurgical instruments and techniques.
However, if a larger vessel is ligated, it may be necessary for the
surgeon to convert the endoscopic procedure into an open-surgical
procedure and thereby abandon the benefits of endoscopic surgery.
Alternatively, the surgeon can seal the larger vessel or
tissue.
[0006] It is thought that the process of coagulating vessels is
fundamentally different from electrosurgical vessel sealing. For
the purposes herein, "coagulation" is defined as a process of
desiccating tissue wherein the tissue cells are ruptured and dried.
"Vessel sealing" or "tissue sealing" is defined as the process of
liquefying the collagen in the tissue so that it reforms into a
fused mass. Coagulation of small vessels is sufficient to
permanently close them, while larger vessels need to be sealed to
assure permanent closure.
[0007] In order to effectively seal larger vessels (or tissue) two
predominant mechanical parameters should be accurately
controlled--the pressure applied to the vessel (tissue) and the gap
distance between the electrodes--both of which are affected by the
thickness of the sealed vessel. More particularly, accurate
application of pressure is important to oppose the walls of the
vessel; to reduce the tissue impedance to a low enough value that
allows enough electrosurgical energy through the tissue; to
overcome the forces of expansion during tissue heating; and to
contribute to the end tissue thickness which is an indication of a
good seal. It has been determined that a typical fused vessel wall
is optimum between about 0.001 and about 0.006 inches. Below this
range, the seal may shred or tear and above this range the lumens
may not be properly or effectively sealed.
[0008] With respect to smaller vessels, the pressure applied to the
tissue tends to become less relevant whereas the gap distance
between the electrically conductive surfaces becomes more
significant for effective sealing. In other words, the chances of
the two electrically conductive surfaces touching during activation
increases as vessels become smaller.
[0009] As mentioned above, in order to properly and effectively
seal larger vessels or tissue, a greater closure force between
opposing jaw members is required. It is known that a large closure
force between the jaws typically requires a large moment about the
pivot for each jaw. This presents a design challenge because the
jaw members are typically affixed with pins which are positioned to
have small moment arms with respect to the pivot of each jaw
member. A large force, coupled with a small moment arm, is
undesirable because the large forces may shear the pins. As a
result, designers compensate for these large closure forces by
either designing instruments with metal pins and/or by designing
instruments which at least partially offload these closure forces
to reduce the chances of mechanical failure. As can be appreciated,
if metal pivot pins are employed, the metal pins should be
insulated to avoid the pin acting as an alternate current path
between the jaw members which may prove detrimental to effective
sealing.
[0010] Increasing the closure forces between electrodes may have
other undesirable effects, e.g., it may cause the opposing
electrodes to come into close contact with one another which may
result in a short circuit and a small closure force may cause
pre-mature movement of the tissue during compression and prior to
activation. As a result thereof, providing an instrument which
consistently provides the appropriate closure force between
opposing electrodes within a preferred pressure range will enhance
the chances of a successful seal. As can be appreciated, relying on
a surgeon to manually provide the appropriate closure force within
the appropriate range on a consistent basis would be difficult and
the resultant effectiveness and quality of the seal may vary.
Moreover, the overall success of creating an effective tissue seal
is greatly reliant upon the user's expertise, vision, dexterity,
and experience in judging the appropriate closure force to
uniformly, consistently and effectively seal the vessel. In other
words, the success of the seal would greatly depend upon the
ultimate skill of the surgeon rather than the efficiency of the
instrument.
[0011] It has been found that the pressure range for assuring a
consistent and effective seal is between about 3 kg/cm.sup.2 to
about 16 kg/cm.sup.2 and, desirably, within a working range of
about 7 kg/cm.sup.2 to about 13 kg/cm.sup.2. Manufacturing an
instrument which is capable of providing a closure pressure within
this working range has been shown to be effective for sealing
arteries, tissues and other vascular bundles.
[0012] Various force-actuating assemblies have been developed in
the past for providing the appropriate closure forces to affect
vessel sealing. For example, one such actuating assembly has been
developed by Valleylab, Inc., of Boulder Colorado, a division of
Tyco Healthcare LP, for use with Valleylab's vessel sealing and
dividing instrument commonly sold under the trademark LIGASURE
ATLAS.RTM.. This assembly includes a four-bar mechanical linkage, a
spring and a drive assembly which cooperate to consistently provide
and maintain tissue pressures within the above working ranges. The
LIGASURE ATLAS.RTM. is presently designed to fit through a 10 mm
cannula and includes a bi-lateral jaw closure mechanism which is
activated by a foot switch. A trigger assembly extends a knife
distally to separate the tissue along the tissue seal. A rotating
mechanism is associated with distal end of the handle to allow a
surgeon to selectively rotate the jaw members to facilitate
grasping tissue. Co-pending U.S. application Ser. Nos. 10/179,863
and 10/116,944 and PCT Application Serial Nos. PCT/US01/01890 and
PCT/7201/11340 describe in detail the operating features of the
LIGASURE ATLAS.RTM. and various methods relating thereto. The
contents of all of these applications are hereby incorporated by
reference herein.
[0013] It would be desirous to develop an instrument that reduces
the number of steps it takes to perform the tissue seal and cut.
Preferably, the instrument would be able to manipulate, clamp, seal
and cut tissue in a single action (e.g., by squeezing a
handle).
SUMMARY
[0014] The present disclosure relates to an endoscopic bipolar
forceps which includes a housing and a shaft affixed to the distal
end of the housing. Preferably, the shaft includes a diameter such
that the shaft is freely insertable through a trocar. The shaft
also includes a longitudinal axis defined therethrough and a pair
of first and second jaw members attached to a distal end thereof.
The forceps includes a drive assembly for moving the first jaw
member relative to the second member from a first position wherein
the jaw members are disposed in spaced relation relative to each
other to a second position wherein the jaw members cooperate to
grasp tissue therebetween. A movable handle is included which is
rotatable about a pivot located above the longitudinal axis of the
shaft. Movement of the movable handle mechanically cooperates with
internal components to move the jaw members from the open and
closed positions, to clamp tissue, to seal tissue and to cut
tissue. Advantageously, the pivot is located a fixed distance above
the longitudinal axis to provide lever-like mechanical advantage to
a drive flange of the drive assembly. The drive flange is located
generally along the longitudinal axis. The forceps is connected to
a source of electrosurgical energy which carries electrical
potentials to each respective jaw member such that the jaw members
are capable of conducting bipolar energy through tissue held
therebetween to affect a tissue seal.
[0015] The forceps includes a switch disposed within the housing
which is electromechanically connected to the energy source.
Advantageously, the switch allows a user to supply bipolar energy
to the jaw members to affect a tissue seal. The switch is activated
by contact from a cutter lever or the movable handle itself when a
user continues to compress the movable handle after the tissue has
been clamped.
[0016] The forceps includes an advanceable knife assembly for
cutting tissue in a forward direction along the tissue seal. The
knife assembly is advanced when a user continues to compress the
movable handle after the tissue has been sealed, forcing the cutter
lever forward. A rotating assembly may also be included for
rotating the jaw members about the longitudinal axis defined
through the shaft.
[0017] In one embodiment, the movable jaw member includes a first
electrical potential and the fixed jaw member includes a second
electrical potential. A lead connects the movable jaw member to the
first potential and a conductive tube (which is disposed through
the shaft) conducts a second electrical potential to the fixed jaw
member. Advantageously, the conductive tube is connected to the
rotating assembly to permit selective rotation of the jaw
members.
[0018] In one embodiment, the drive assembly includes a
reciprocating sleeve which upon activation of the movable handle,
translates atop the rotating conductive tube to move the movable
jaw member relative to the fixed jaw member. In one embodiment, the
movable jaw member includes a detent which extends beyond the fixed
jaw member which is designed for engagement with the reciprocating
sleeve such that, upon translation thereof, the movable jaw member
moves relative to the fixed jaw member. Advantageously, a spring is
included with the drive assembly to facilitate actuation of the
movable handle and to ensure the closure force is maintained within
the working range of about 3 kg/cm.sup.2 to about 16 kg/cm.sup.2
and, preferably, about 7 kg/cm.sup.2 to about 13 kg/cm.sup.2
[0019] In one embodiment, at least one of the jaw members includes
a series of stop members disposed thereon for regulating the
distance between the jaw members (i.e., creating a gap between the
two opposing jaw members) during the sealing process. As can be
appreciated, regulating the gap distance between opposing jaw
members along with maintaining the closing pressure to within the
above-described ranges will produce a reliable and consistent
tissue seal.
[0020] The present disclosure also relates to an endoscopic bipolar
forceps which includes a shaft having a movable jaw member and a
fixed jaw member at a distal end thereof. The forceps also includes
a drive assembly for moving the movable jaw member relative to the
fixed jaw member from a first position wherein the movable jaw
member is disposed in spaced relation relative to the fixed jaw
member to a second position wherein the movable jaw member is
closer to the fixed jaw member for manipulating tissue. A movable
handle is included which actuates the drive assembly to move the
movable jaw member.
[0021] The forceps connects to a source of electrosurgical energy
which is conducted to each jaw member such that the jaw members are
capable of conducting bipolar energy through tissue held
therebetween to affect a tissue seal. Advantageously, the forceps
also includes a selectively advanceable knife assembly for cutting
tissue in a distal direction along the tissue seal and a stop
member disposed on at least one of the jaw members for regulating
the distance between jaw members during sealing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Various embodiments of the subject instrument are described
herein with reference to the drawings wherein:
[0023] FIG. 1 is a partial schematic view of one embodiment of an
endoscopic bipolar forceps having a movable thumb handle in an
unactuated position according to one aspect of the present
disclosure;
[0024] FIG. 2 is a partial schematic view of the forceps of FIG. 1
illustrated in a partially actuated position;
[0025] FIG. 3 is a partial schematic view of another embodiment of
an endoscopic bipolar forceps having a movable finger handle
illustrated in a partially actuated position;
[0026] FIG. 4 is an enlarged, perspective view of an end effector
assembly with jaw members shown in an open configuration;
[0027] FIG. 5 is an enlarged, side view of the end effector
assembly of FIG. 4;
[0028] FIG. 6 is an enlarged, perspective view of the tissue
contacting side of an upper jaw member of the end effector
assembly;
[0029] FIG. 7 is an enlarged, broken perspective view showing the
end effector assembly and highlighting a cam-like closing mechanism
which cooperates with a reciprocating pull sleeve to move the jaw
members relative to one another;
[0030] FIG. 8 is a full perspective view of the end effector
assembly of FIG. 7;
[0031] FIG. 9 is a left, perspective view of a rotating assembly,
drive assembly, knife assembly and lower jaw member according to
the present disclosure;
[0032] FIG. 10 is a rear, perspective view of the rotating
assembly, drive assembly and knife assembly;
[0033] FIG. 11 is an enlarged, top, perspective view of the end
effector assembly with parts separated;
[0034] FIG. 12 is an enlarged, perspective view of the knife
assembly;
[0035] FIG. 13 is an enlarged, perspective view of the rotating
assembly;
[0036] FIG. 14 is an enlarged, perspective view of the drive
assembly;
[0037] FIG. 15 is an enlarged, perspective view of the knife
assembly with parts separated;
[0038] FIG. 16 is an enlarged view of the indicated area of detail
of FIG. 15;
[0039] FIG. 17 is a greatly-enlarged, perspective view of a distal
end of the knife assembly;
[0040] FIG. 18 is a greatly-enlarged, perspective view of a knife
drive of the knife assembly;
[0041] FIG. 19 is an enlarged, perspective view of the rotating
assembly and lower jaw member with parts separated;
[0042] FIG. 20 is a cross section along line 20-20 of FIG. 19;
[0043] FIG. 21 is a greatly-enlarged, perspective view of the lower
jaw member;
[0044] FIG. 22 is an enlarged, perspective view of the drive
assembly;
[0045] FIG. 23 is an enlarged perspective view of the drive
assembly of
[0046] FIG. 22 with parts separated;
[0047] FIG. 24 is a greatly-enlarged, cross section of the shaft
taken along line 24-24 of FIG. 25;
[0048] FIG. 25 is a side, cross section of the shaft and end
effector assembly;
[0049] FIG. 26 is a greatly-enlarged, perspective view of a handle
assembly and latch mechanism for use with the forceps;
[0050] FIG. 27 is a greatly-enlarged view of an end effector;
[0051] FIG. 28 is a greatly-enlarged view of the drive
assembly;
[0052] FIG. 29 is an enlarged, rear, perspective view of the end
effector shown grasping tissue;
[0053] FIG. 30 is an enlarged view of a tissue seal;
[0054] FIG. 31 is a side, cross section of a tissue seal taken
along line 31-31 of FIG. 30;
[0055] FIG. 32 is an enlarged view of the end effector showing
distal translation of the knife; and
[0056] FIG. 33 is a side, cross section of a tissue seal after
separation by the knife assembly.
DETAILED DESCRIPTION
[0057] Turning now to FIGS. 1-3, one embodiment of an endoscopic
bipolar forceps 10 is shown for use with various surgical
procedures and generally includes a housing 20, a handle assembly
30, a rotating assembly 80, an end effector assembly 100, a knife
assembly 140 (see FIGS. 10, 12, 15-18), a drive assembly 150, a
switch 500 and a latch assembly 600 which all mutually cooperate to
grasp, seal and divide tubular vessels and vascular tissue 420
(FIG. 29). Although the majority of the figure drawings depict a
bipolar forceps 10 for use in connection with endoscopic surgical
procedures, the present disclosure may be used for more traditional
open surgical procedures. For the purposes herein, the forceps 10
is described in terms of an endoscopic instrument, however, it is
contemplated that an open version of the forceps may also include
the same or similar operating components and features as described
below.
[0058] Forceps 10 includes a shaft 12 which has a distal end 16
dimensioned to mechanically engage the end effector assembly 100
and a proximal end 14 which mechanically engages the housing 20. In
the drawings and in the descriptions which follow, the term
"proximal," as is traditional, will refer to the end of the forceps
10 which is closer to the user, while the term "distal" will refer
to the end which is farther from the user.
[0059] Forceps 10 also includes an electrosurgical cable 310 which
connects the forceps 10 to a source of electrosurgical energy,
e.g., a generator (not shown). Generators such as those sold by
Valleylab--a division of Tyco Healthcare LP, located in Boulder,
Colorado are contemplated for use as a source of electrosurgical
energy, e.g., FORCE EZ.TM. Electrosurgical Generator, FORCE FX.TM.
Electrosurgical Generator, FORCE 1C.TM., FORCE 2.TM. Generator,
SurgiStat.TM. II. One such system is described in commonly-owned
U.S. Pat. No. 6,033,399 entitled "ELECTROSURGICAL GENERATOR WITH
ADAPTIVE POWER CONTROL," the entire contents of which are hereby
incorporated by reference herein. Other systems have been described
in commonly-owned U.S. Pat. No. 6,187,003 entitled "BIPOLAR
ELECTROSURGICAL INSTRUMENT FOR SEALING VESSELS," the entire
contents of which are also incorporated by reference herein.
[0060] In one embodiment, the generator includes various safety and
performance features including isolated output, independent
activation of accessories. In one embodiment, the electrosurgical
generator includes Valleylab's Instant Response.TM. technology
features which provide an advanced feedback system to sense changes
in tissue 200 times per second and adjust voltage and current to
maintain appropriate power. The Instant Response.TM. technology is
believed to provide one or more of the following benefits to
surgical procedure:
[0061] Consistent clinical effect through all tissue types;
[0062] Reduced thermal spread and risk of collateral tissue
damage;
[0063] Less need to "turn up the generator"; and
[0064] Designed for the minimally invasive environment.
[0065] Cable 310 is internally divided into cable leads (not shown)
which each transmit electrosurgical energy through their respective
feed paths through the forceps 10 to the end effector assembly 100.
A detailed discussion of the cable leads and their connections
through the forceps 10 is described in commonly-assigned,
co-pending U.S. application Ser. No. 10/460,926 entitled "VESSEL
SEALER AND DIVIDER FOR USE WITH SMALL TROCARS AND CANNULAS" by
Dycus et al., which is hereby incorporated by reference in its
entirety herein.
[0066] Handle assembly 30 includes a fixed handle 50, a movable
handle 40, a cutter lever 700 and a handle detent 710. Fixed handle
50 is integrally associated with housing 20 and movable handle 40
is movable relative to fixed handle 50 as explained in more detail
below with respect to the operation of the forceps 10.
[0067] In one embodiment, rotating assembly 80 is integrally
associated with the housing 20 and is rotatable approximately 180
degrees in either direction about a longitudinal axis "A" (FIGS. 1
and 3). Details of the rotating assembly 80 are described in more
detail with respect to FIGS. 9 and 10.
[0068] Housing 20 may be formed from two housing halves (not shown)
which each include a plurality of interfaces which are dimensioned
to mechanically align and engage one another to form housing 20 and
enclose the internal working components of forceps 10. A detailed
discussion of the housing halves and how they mechanically engage
with one another is described in commonly-assigned, co-pending U.S.
Application Ser. No. 10/460,926 entitled "VESSEL SEALER AND DIVIDER
FOR USE WITH SMALL TROCARS AND CANNULAS" by Dycus et al., which is
hereby incorporated by reference in its entirety herein.
[0069] It is envisioned that a plurality of additional interfaces
(not shown) may be disposed at various points around the periphery
of housing halves for ultrasonic welding purposes, e.g., energy
direction/deflection points. It is also contemplated that housing
halves (as well as the other components described below) may be
assembled together in any fashion known in the art. For example,
alignment pins, snap-like interfaces, tongue and groove interfaces,
locking tabs, adhesive ports, etc. may all be utilized either alone
or in combination for assembly purposes.
[0070] Rotating assembly 80 includes two halves 82a and 82b (see
FIGS. 13 and 19) which, when assembled, form the rotating assembly
80 which, in turn, houses the drive assembly 150 and the knife
assembly 140. Half 82b includes a series of detents/flanges 375a,
375b, 375c and 375d which are dimensioned to engage a pair of
corresponding sockets or other mechanical interfaces (not shown)
disposed within rotating half 82a. In one embodiment, movable
handle 40 is of unitary construction and is operatively connected
to the housing 20 and the fixed handle 50 during the assembly
process.
[0071] As mentioned above, end effector assembly 100 is attached at
the distal end 14 of shaft 12 and includes a pair of opposing jaw
members 110 and 120. Movable handle 40 of handle assembly 30 is in
mechanical cooperation with drive assembly 150 which, together,
mechanically cooperate to impart movement of the jaw members 110
and 120 from an open position wherein the jaw members 110 and 120
are disposed in spaced relation relative to one another, to a
clamping or closed position wherein the jaw members 110 and 120
cooperate to grasp tissue 420 (FIG. 29) therebetween.
[0072] It is envisioned that jaw members 110 and 120 of end
effector assembly 100 may be curved (as illustrated in FIG. 3) in
order to reach specific anatomical structures and promote more
consistent seals for certain procedures. For example, it is
contemplated that dimensioning the jaw members 110 and 120 at an
angle of about 45 degrees to about 70 degrees is preferred for
accessing and sealing specific anatomical structures relevant to
prostatectomies and cystectomies, e.g., the dorsal vein complex and
the lateral pedicles. Other angles may be preferred for different
surgical procedures. Such an end effector assembly with curved jaw
members is described in commonly-assigned, co-pending U.S.
application Ser. No. 10/834,764 entitled "ELECTROSURGICAL
INSTRUMENT WHICH REDUCES DAMAGE TO ADJACENT TISSUE," by Dycus et
al., which is hereby incorporated by reference in its entirety
herein.
[0073] It is envisioned that the forceps 10 may be designed such
that it is fully or partially disposable depending upon a
particular purpose or to achieve a particular result. For example,
end effector assembly 100 may be selectively and releasably
engageable with the distal end 16 of the shaft 12 and/or the
proximal end 14 of shaft 12 may be selectively and releasably
engageable with the housing 20 and the handle assembly 30. In
either of these two instances, the forceps 10 would be considered
"partially disposable" or "reposable," i.e., a new or different end
effector assembly 100 (or end effector assembly 100 and shaft 12)
selectively replaces the old end effector assembly 100 as needed.
As can be appreciated, the presently disclosed electrical
connections would have to be altered to modify the instrument to a
reposable forceps.
[0074] Turning now to the more detailed features of the present
disclosure, movable handle 40 includes a finger loop 41 which has
an aperture 42 defined therethrough which enables a user to grasp
and move the movable handle 40 relative to the fixed handle 50.
FIGS. 1 and 2 illustrate a movable handle 40 with finger loop 41
designed to be grasped and moved by a thumb, while FIG. 3
illustrates a movable handle 40 with finger loop 41 designed to be
grasped and moved by one or more fingers. Further, the movable
handle 40 of FIGS. 1 and 2 is on the proximal side of fixed handle
50, while the movable handle 40 of FIG. 3 is on the distal side of
fixed handle 50. Movable handle 40 may also include one ore more
ergonomically-enhanced gripping elements (not shown) disposed along
the inner peripheral edge of aperture 42 or on fixed handle 50
which is designed to facilitate gripping of the handles 40 and 50
during activation. It is envisioned that the gripping element may
include one or more protuberances, scallops and/or ribs to enhance
gripping.
[0075] As best seen in FIGS. 1 and 2, movable handle 40 is
selectively moveable about a pivot point 29 from a first position
(FIG. 1) relative to fixed handle 50 to a second position (FIG. 2)
in closer proximity to the fixed handle 50 which, as explained
below, imparts movement of the jaw members 110 and 120 relative to
one another. It is contemplated that there may be intermediate
positions between those shown in FIGS. 1 and 2, e.g., discrete
closure points which correspond to ratchet positions as discussed
in more detail below. Additionally, continued movement of the
moveable handle 40 towards the fixed handle 50 first engages switch
500, which causes the tissue to be sealed, and then engages knife
assembly 140, which cuts the tissue. Operation of the forceps is
discussed further below.
[0076] As best seen in FIGS. 1-3 and 26, the lower end of the
movable handle 40 includes a flange 90. Flange 90 also includes an
end 95 which rides within a predefined channel 52 (see FIG. 26) and
mechanically engages with ramps 57 disposed within fixed handle 50.
Additional features with respect to the end 95 are explained below
in the detailed discussion of the operational features of the
forceps 10.
[0077] Movable handle 40 is designed to provide a distinct
mechanical advantage over conventional handle assemblies due to the
position of the pivot point 29 relative to the longitudinal axis
"A" of the shaft 12 and the disposition of the drive assembly 150
along longitudinal axis "A." In other words, it is envisioned that
by positioning the pivot point 29 above the drive assembly 150, the
user gains lever-like mechanical advantage to actuate the jaw
members 110 and 120 enabling the user to close the jaw members 110
and 120 with lesser force while still generating the required
forces necessary to affect a proper and effective tissue seal and
to cut the tissue 420. It is also envisioned that the unilateral
design of the end effector assembly 100 will also increase
mechanical advantage as explained in more detail below.
[0078] As shown best in FIGS. 4-8, the end effector assembly 100
includes opposing jaw members 110 and 120 which cooperate to
effectively grasp tissue 420 for sealing purposes. The end effector
assembly 100 is designed as a unilateral assembly in this
particular embodiment, i.e., jaw member 120 is fixed relative to
the shaft 12 and jaw member 110 pivots about a pivot pin 103 to
grasp tissue 420. A bilateral jaw assembly is also envisioned
wherein both jaw members are movable.
[0079] More particularly, the unilateral end effector assembly 100
includes one stationary or fixed jaw member 120 mounted in fixed
relation to the shaft 12 and pivoting jaw member 110 mounted about
a pivot pin 103 attached to the stationary jaw member 120. A
reciprocating sleeve 60 is slidingly disposed within the shaft 12
and is remotely operable by the drive assembly 150. The pivoting
jaw member 110 includes a detent or protrusion 117 which extends
from jaw member 110 through an aperture 62 disposed within the
reciprocating sleeve 60 (FIG. 8). The pivoting jaw member 110 is
actuated by sliding the sleeve 60 axially within the shaft 12 such
that a distal end 63 of the aperture 62 abuts against the detent
117 on the pivoting jaw member 110 (see FIGS. 7 and 8). Pulling the
sleeve 60 proximally closes the jaw members 110 and 120 about
tissue 420 grasped therebetween and pushing the sleeve 60 distally
opens the jaw members 110 and 120 for grasping purposes.
[0080] As best illustrated in FIGS. 4 and 6, a knife channel 115a
and 115b runs through the center of the jaw members 110 and 120,
respectively, such that a knife blade 185 from the knife assembly
140 can cut the tissue 420 grasped between the jaw members 110 and
120 when the jaw members 110 and 120 are in a closed position. More
particularly, the knife blade 185 can only be advanced through the
tissue 420 when the jaw members 110 and 120 are closed thus
preventing accidental or premature activation of the knife blade
185 through the tissue 420. Put simply, the knife channel 115 (made
up of half channels 115a and 115b) is blocked when the jaws members
110 and 120 are opened and the knife channel 115 is aligned for
distal activation when the jaw members 110 and 120 are closed (see
FIGS. 25 and 27). It is also envisioned that the unilateral end
effector assembly 100 may be structured such that electrical energy
can be routed through the sleeve 60 at the protrusion 117 contact
point with the sleeve 60 or using a "brush" or lever (not shown) to
contact the back of the moving jaw member 110 when the jaw member
110 closes. In this instance, the electrical energy would be routed
through the protrusion 117 to the stationary jaw member 120.
Alternatively, a cable lead 311 may be routed to energize the
stationary jaw member 120 and the other electrical potential may be
conducted through the sleeve 60 and transferred to the pivoting jaw
member 110 which establishes electrical continuity upon retraction
of the sleeve 60. It is envisioned that this particular envisioned
embodiment will provide at least two important safety features: 1)
the knife blade 185 cannot extend while the jaw members 110 and 120
are opened; and 2) electrical continuity to the jaw members 110 and
120 is made only when the jaw members are closed. The illustrated
forceps 10 only includes the knife channel 115.
[0081] As best shown in FIG. 4, jaw member 110 also includes a jaw
housing 116 which has an insulative substrate or insulator 114 and
an electrically conducive surface 112. In one embodiment, insulator
114 is dimensioned to securely engage the electrically conductive
sealing surface 112. This may be accomplished by stamping, by
overmolding, by overmolding a stamped electrically conductive
sealing plate and/or by overmolding a metal injection molded seal
plate. For example and as shown in FIG. 11, the electrically
conductive sealing plate 112 includes a series of upwardly
extending flanges 111a and 111b which are designed to matingly
engage the insulator 114. The insulator 114 includes a shoe-like
interface 107 disposed at a distal end thereof which is dimensioned
to engage the jaw housing 116 in a slip-fit manner. The shoe-like
interface 107 may also be overmolded about the outer periphery of
the jaw 110 during a manufacturing step. It is envisioned that
cable lead 311 terminates within the shoe-like interface 107 at the
point where cable lead 311 electrically connects to the seal plate
112 (not shown). The movable jaw member 110 also includes a wire
channel 113 which is designed to guide cable lead 311 into
electrical continuity with sealing plate 112.
[0082] All of these manufacturing techniques produce jaw member 110
having an electrically conductive surface 112 which is
substantially surrounded by an insulating substrate 114. In one
embodiment, the insulator 114, electrically conductive sealing
surface 112 and the outer, non-conductive jaw housing 116 are
dimensioned to limit and/or reduce many of the known undesirable
effects related to tissue sealing, e.g., flashover, thermal spread
and stray current dissipation. Alternatively, it is also envisioned
that the jaw members 110 and 120 may be manufactured from a
ceramic-like material and the electrically conductive surface(s)
112 may be coated onto the ceramic-like jaw members 110 and
120.
[0083] Jaw member 110 includes a pivot flange 118 (FIG. 6) which
includes a protrusion 117. Protrusion 117 extends from pivot flange
118 and includes an arcuately-shaped inner surface 111 dimensioned
to matingly engage the aperture 62 of sleeve 60 upon retraction
thereof. Pivot flange 118 also includes a pin slot 119 which is
dimensioned to engage pivot pin 103 to allow jaw member 110 to
rotate relative to jaw member 120 upon retraction of the
reciprocating sleeve 60. As explained in more detail below, pivot
pin 103 also mounts to the stationary jaw member 120 through a pair
of apertures 101a and 101b disposed within a proximal portion of
the jaw member 120.
[0084] It is envisioned that the electrically conductive sealing
surface 112 may also include an outer peripheral edge which has a
pre-defined radius and the insulator 114 meets the electrically
conductive sealing surface 112 along an adjoining edge of the
sealing surface 112 in a generally tangential position. In one
embodiment, at the interface, the electrically conductive surface
112 is raised relative to the insulator 114. These and other
envisioned embodiments are discussed in co-pending, commonly
assigned Application Serial No. PCT/US01/11412 entitled
"ELECTROSURGICAL INSTRUMENT WHICH REDUCES COLLATERAL DAMAGE TO
ADJACENT TISSUE" by Johnson et al. and co-pending, commonly
assigned Application Serial No. PCT/US01/11411 entitled
"ELECTROSURGICAL INSTRUMENT WHICH IS DESIGNED TO REDUCE THE
INCIDENCE OF FLASHOVER" by Johnson et al., both of which are hereby
incorporated by reference in their entirety herein.
[0085] The electrosurgical seal and/or cut can be made utilizing
various electrode assemblies on the jaw members, such that energy
is applied to the tissue through sealing plates. This and other
envisioned electrosurgical sealing and cutting techniques are
discussed in co-pending, commonly assigned application Ser. No.
10/932,612 entitled "VESSEL SEALING INSTRUMENT WITH ELECTRICAL
CUTTING MECHANISM" by Johnson et al., which is hereby incorporated
by reference in its entirety herein.
[0086] In one embodiment, the electrically conductive surface 112
and the insulator 114, when assembled, form a
longitudinally-oriented slot 115a defined therethrough for
reciprocation of the knife blade 185. It is envisioned that the
knife channel 115a cooperates with a corresponding knife channel
115b defined in stationary jaw member 120 to facilitate
longitudinal extension of the knife blade 185 along a preferred
cutting plane to effectively and accurately separate the tissue 420
along the formed tissue seal 450 (see FIGS. 30 and 33).
[0087] Jaw member 120 includes similar elements to jaw member 110
such as jaw housing 126 having an insulator 124 and an electrically
conductive sealing surface 122 which is dimensioned to securely
engage the insulator 124. Likewise, the electrically conductive
surface 122 and the insulator 124, when assembled, include a
longitudinally-oriented channel 115a defined therethrough for
reciprocation of the knife blade 185. As mentioned above, when the
jaw members 110 and 120 are closed about tissue 420, knife channels
115a and 115b form a complete knife channel 115 to allow
longitudinal extension of the knife blade 185 in a distal fashion
to sever tissue 420 along the tissue seal 450. It is also
envisioned that the knife channel 115 may be completely disposed in
one of the two jaw members, e.g., jaw member 120, depending upon a
particular purpose. It is envisioned that the fixed jaw member 120
may be assembled in a similar manner as described above with
respect to jaw member 110.
[0088] As best seen in FIG. 4, jaw member 120 includes a series of
stop members 750 disposed on the inner facing surfaces of the
electrically conductive sealing surface 122 to facilitate gripping
and manipulation of tissue and to define a gap "G" (FIG. 29)
between opposing jaw members 110 and 120 during sealing and cutting
of tissue. It is envisioned that the series of stop members 750 may
be employed on one or both jaw members 110 and 120 depending upon a
particular purpose or to achieve a desired result. A detailed
discussion of these and other envisioned stop members 750 as well
as various manufacturing and assembling processes for attaching
and/or affixing the stop members 750 to the electrically conductive
sealing surfaces 112, 122 are described in commonly-assigned,
co-pending U.S. application Ser. No. PCT/US01/11413 entitled
"VESSEL SEALER AND DIVIDER WITH NON-CONDUCTIVE STOP MEMBERS" by
Dycus et al. which is hereby incorporated by reference in its
entirety herein.
[0089] Jaw member 120 is designed to be fixed to the end of a
rotating tube 160 which is part of the rotating assembly 80 such
that rotation of the tube 160 will impart rotation to the end
effector assembly 100 (see FIGS. 13 and 19). Jaw member 120
includes a rear C-shaped cuff 170 having a slot 177 defined therein
which is dimensioned to receive a slide pin 171. More particularly,
slide pin 171 includes a slide rail 176 which extends substantially
the length thereof which is dimensioned to slide into friction-fit
engagement within slot 177. A pair of chamfered plates 172a and
172b extend generally radially from the slide rail 176 and include
a radius which is substantially the same radius as the outer
periphery of the rotating tube 160 such that the shaft 12 can
encompass each of the same upon assembly.
[0090] As best shown in FIGS. 19 and 20, the rotating tube 160
includes an elongated guide slot 167 disposed in an upper portion
thereof which is dimensioned to carry cable lead 311 therealong.
The chamfered plates 172a and 172b also form a wire channel 175
which is dimensioned to guide the cable lead 311 from the tube 160
and into the movable jaw member 110 (see FIG. 4). Cable lead 311
carries a first electrical potential to movable jaw 110.
[0091] As shown in FIG. 19, the distal end of the tube 160 is
generally C-shaped to include two upwardly extending flanges 162a
and 162b which define a cavity 165 for receiving the proximal end
of the fixed jaw member 120 inclusive of C-shaped cuff 170 and
slide pin 171 (see FIG. 21). In one embodiment, the tube cavity 165
retains and secures the jaw member 120 in a friction-fit manner,
however, the jaw member 120 may be welded to the tube 160 depending
upon a particular purpose. Tube 160 also includes an inner cavity
169 defined therethrough which reciprocates the knife assembly 140
upon distal activation thereof and an elongated guide rail 163
which guides the knife assembly 140 during distal activation (see
FIG. 20). The details with respect to the knife assembly are
explained in more detail with respect to FIGS. 15-18. The proximal
end of tube 160 includes a laterally oriented slot 168 which is
designed to interface with the rotating assembly 80 as described
below.
[0092] FIG. 19 also shows the rotating assembly 80 which includes
C-shaped rotating halves 82a and 82b which, when assembled about
tube 160, form a generally circular rotating member 82. More
particularly, each rotating half, e.g., 82b, includes a series of
mechanical interfaces 375a, 375b, 375c and 375d which matingly
engage a corresponding series of mechanical interfaces in the other
half, e.g., 82a, to form rotating member 82. Half 82b also includes
a tab 89b which, together with a corresponding tab 89a disposed on
half 82a (phantomly illustrated), cooperate to matingly engage slot
168 disposed on tube 160. As can be appreciated, this permits
selective rotation of the tube 160 about axis "A" by manipulating
the rotating member 82 in the direction of the arrow "B" (see FIG.
2).
[0093] As best shown in the exploded view of FIG. 11, jaw members
110 and 120 are pivotably mounted with respect to one another such
that jaw member 110 pivots in a unilateral fashion from a first
open position to a second closed position for grasping and
manipulating tissue 420. More particularly, fixed jaw member 120
includes a pair of proximal, upwardly extending flanges 125a and
125b which define a cavity 121 dimensioned to receive flange 118 of
movable jaw member 110 therein. As explained in detail below with
respect to the operation of the jaw members 110 and 120, proximal
movement of the tube 60 engages detent 117 to pivot the jaw member
110 to a closed position.
[0094] FIGS. 1-3 show the housing 20 and the component features
thereof, namely, the handle assembly 30, the rotating assembly 80,
the knife assembly 140, the drive assembly 150, the switch 500, the
latch assembly 600 and a cutter lever 700.
[0095] The housing includes two halves (constructed similarly to
the halves of rotating assembly 80, as discussed above with
reference to FIG. 19) which, when mated, form housing 20. As can be
appreciated, housing 20, once formed, houses the various assemblies
identified above which will enable a user to selectively
manipulate, grasp, seal and sever tissue 420 in a single action. In
one embodiment, each half of the housing includes a series of
mechanical interfacing components (not shown) which align and/or
mate with a corresponding series of mechanical interfaces to align
the two housing halves about the inner components and assemblies.
The housing halves can then be sonic welded to secure the housing
halves once assembled.
[0096] The movable handle 40 includes clevis 45 which pivots about
pivot point 29 to pull the reciprocating sleeve 60 along
longitudinal axis "A" and force a drive flange 47 against the drive
assembly 150 which, in turn, closes the jaw members 110 and 120, as
explained above. As mentioned above, the lower end of the movable
handle 40 includes a flange 90 which has an end 95 which rides
within a predefined channel 52 disposed within fixed handle 50 (see
FIG. 26). The arrangement of the clevis 45 and the pivot point 29
of the movable handle 40 provides a distinct mechanical advantage
over conventional handle assemblies due to the position of the
pivot point 29 relative to the longitudinal axis "A" of the drive
flange 47. In other words, by positioning the pivot point 29 above
the drive flange 47, the user gains lever-like mechanical advantage
to actuate the jaw members 110 and 120. This reduces the overall
amount of mechanical force necessary to close the jaw members 110
and 120 to affect a tissue seal.
[0097] Movable handle 40 also includes a finger loop 41 which
defines opening 42 which is dimensioned to facilitate grasping the
movable handle 40. In one embodiment, finger loop 41 includes
rubber insert which enhances the overall ergonomic "feel" of the
movable handle 40.
[0098] Handle assembly 30 further includes a cutter lever 700
positioned within housing 20. When movable handle 40 is actuated
(squeezed) past a certain threshold, a switch lever 502 is
depressed by movable handle 40 to initiate a tissue seal cycle. A
flexible detent 602 provides tactile feedback that the movable
handle 40 is nearing an exit of the latch sealing zone and an end
of the ramps 57. When the movable handle 40 is pushed past the
flexible detent 602, end 95 of flange 90 drops down from ramps 57
and the user is able to return the movable handle 40 proximally to
open the jaw members 110, 120 without cutting the seal. The user
may also close the movable handle 40 to cut the sealed tissue 420
via actuation of the lever 700. When closing movable handle 40
farther to cut tissue, end 95 contacts a latch spring 704, which
provides resistance on the movable handle 40. This provides an
indication to the user that tissue cutting is about to begin.
[0099] The movable handle 40 or a handle detent 710 contacts the
cutter lever 700, which activates knife assembly 140, which severs
the tissue 420. As can be appreciated, this prevents accidental or
premature severing of tissue 420 prior to completion of the tissue
seal 450. The generator may provide an audible signal or other type
of feedback when the seal cycle is complete. The surgeon can then
safely cut the seal or return the movable handle 40 without
cutting. In an alternative method, an electromechanical, mechanical
or electrical feature could prevent cutting without initially
sealing or without the surgeon activating a special over-ride
feature.
[0100] Fixed handle 50 includes a channel 52 (FIG. 26) defined
therein which is dimensioned to receive end 95 of flange 90 when
movable handle 40 is actuated. The end 95 of flange 90 is
dimensioned for facile reception with ramps 57 within channel 52 of
fixed handle 50. It is envisioned that flange 90 may be dimensioned
to allow a user to selectively, progressively and/or incrementally
move jaw members 110 and 120 relative to one another from the open
to closed positions. For example, it is contemplated that end 95
and ramps 57 may include a ratchet-like interface (FIGS. 1-3) which
lockingly engages the movable handle 40 and, therefore, jaw members
110 and 120 at selective, incremental positions relative to one
another depending upon a particular purpose. Such a ratchet-like
interface can also prevent the movable handle 40 from becoming
unactuated prior to the severing of tissue 420.
[0101] It is also contemplated that the ratchet-like interface
between the end 95 and ramps 57 are configured such that a catch
basin is disposed between each step of the ratchet. A catch basin
is described in commonly-assigned, co-pending U.S. application Ser.
No. 10/460,926 entitled "VESSEL SEALER AND DIVIDER FOR USE WITH
SMALL TROCARS AND CANNULAS" by Dycus et al., which is hereby
incorporated by reference in its entirety herein, and can be
utilized to be a stopping point between each of the functions that
the movable handle 40 can control (i.e., manipulation, clamping,
sealing and cutting). Employing such a catch basin will enable the
user to selectively advance the movable handle 40, while ensuring
the functions are carried out in the proper order.
[0102] Other mechanisms may also be employed to control and/or
limit the movement of movable handle 40 relative to fixed handle 50
(and jaw members 110 and 120) such as, e.g., hydraulic,
semi-hydraulic, linear actuator(s), gas-assisted mechanisms and/or
gearing systems.
[0103] In one embodiment, forceps 10 includes at least one tactile
element which provides tactile feedback to the user to signify when
tissue is being grasped, when the tissue has been sealed and/or
when the tissue has been cut. Such a tactile element may include
the turning on/off of lights (not shown) on housing 20 or
mechanical vibrations being created in the fixed handle 50 or
movable handle 40. It is further envisioned for a sensor to be
disposed on or within forceps 10 to alert to the user when one or
more completion stages has occurred, i.e., at the completion of
tissue grasping, tissue sealing and/or tissue cutting.
[0104] As best illustrated in FIG. 26, housing halves form an
internal cavity which predefines the channel 52 within fixed handle
50 such that an entrance pathway 51 and an exit pathway 58 are
formed for reciprocation of the end 95 of flange 90 therein. When
assembled, two ramps 57 are positioned to define a rail or track
192, such that the flange 90 can fit between the ramps 57 and end
95 moves along the track 192. During movement of end 95 of flange
90 along the entrance and exit pathways 51 and 58, respectively,
the end 95 rides along track 192 according to the particular
dimensions of the ramps 57, which, as can be appreciated,
predetermines part of the overall pivoting motion of movable handle
40 relative to fixed handle 50.
[0105] As best illustrated in FIGS. 1 and 2, once actuated, movable
handle 40 moves in a generally arcuate fashion towards fixed handle
50 about pivot point 29. End 95 of flange 90 moves along ramps 57
(shown as a single ramp in FIGS. 1-3 for clarity) which forces
drive flange 47 against the drive assembly 150 which, in turn,
pulls reciprocating sleeve 60 in a generally proximal direction to
close jaw member 110 relative to jaw member 120. Continued
actuation of movable handle 40 forces end 95 of flange 90 farther
along ramps 57 and forces the movable handle 40 or cutter lever 700
into a contact 502 of switch 500, which causes the sealing of
tissue 420 to occur. Continued actuation of movable handle 40 then
forces movable handle detent 710 into cutter lever 700 to initiate
engagement thereof. A detailed discussion of how the sealing
occurs, including by electro-mechanical means, is described in
commonly-assigned, co-pending U.S. application Ser. No. 10/932,612
entitled "VESSEL SEALING INSTRUMENT WITH ELECTRICAL CUTTING
MECHANISM" by Johnson et al., which is hereby incorporated
herein.
[0106] Continued actuation of movable handle 40 forces end 95 of
flange 90 farther along the ramps 57 and into a flexible latch
detent 602. The user feels a resistance when the end 95 contacts
the flexible latch detent 602, which signifies that the device is
about to exit the sealing position and either cut or return to its
original position without cutting. To cut the tissue seal 450, the
user continues to actuate the movable handle 40, such that the
cutter lever 700 activates knife assembly 140, which in turn severs
the tissue seal 450. At this cutting stage, the end 95 contacts a
detent rib 704 which provides increased resistance to the user
indicating that cutting of the tissue is about to begin. The end 95
slides distally along detent rib 704 (in the embodiment shown in
FIG. 3, the detent rib 704 is contacted proximally). When the cut
is complete, the detent rib 704 may stop the motion of the end 95
and allow flange 90 to follow its return path 58 (FIG. 26), as
discussed above. Therefore, a full actuation of movable handle 40
grasps and clamps tissue 420, seals the tissue 420, and cuts the
tissue seal 450, before returning the movable handle 40 to its
original, unactuated position.
[0107] FIG. 3 illustrates the forceps 10 with the movable handle 40
located on the distal side of fixed handle 50. As can be
appreciated, the internal dynamics of this embodiment are similar
to those of the forceps illustrated in FIGS. 1 and 2, thus causing
the forceps 10 to function in a comparable way.
[0108] It is envisioned that the flexible latch detent 602 may
include one or more electro-mechanical switches, similar to those
of switch 500, to seal the tissue 420. In this embodiment,
handswitch 500 and contact 502 are not necessary. Details relating
to the handswitch are discussed below.
[0109] It is also envisioned that latch spring 704 may include one
or more mechanical or electro-mechanical switches or activations to
drive the knife assembly 140 to cut the tissue seal 450, such that
when end 95 contacts the latch spring 704, the tissue seal 450 is
automatically severed.
[0110] The operating features and relative movements of the
internal working components of the forceps 10 are shown as phantom
lines in the various figures.
[0111] As the movable handle 40 is actuated and flange 90 is
incorporated into channel 52 of fixed handle 50, the drive flange
47, through the mechanical advantage of the above-the-center pivot
points, biases a ring flange 154 of drive ring 159 which, in turn,
compresses a drive spring 67 against a rear ring 156 of the drive
assembly 150 (FIG. 28). As a result thereof, the rear ring 156
reciprocates sleeve 60 proximally which, in turn, closes jaw member
110 onto jaw member 120. It is envisioned that the utilization of
an over-the-center pivoting mechanism will enable the user to
selectively compress the drive spring 67 a specific distance which,
in turn, imparts a specific pulling load on the reciprocating
sleeve 60 which is converted to a rotational torque about the jaw
pivot pin 103. As a result, a specific closure force can be
transmitted to the opposing jaw members 110 and 120.
[0112] FIG. 26 shows the initial actuation of movable handle 40
towards fixed handle 50 which causes the end 95 of flange 90 to
move generally proximally and upwardly along entrance pathway 51
(this illustration is the embodiment of the forceps shown in FIG.
3; the internal environment of the forceps of FIGS. 1 and 2 is
similarly situated). During movement of the flange 90 along the
entrance and exit pathways 51 and 58, respectively, the end 95
rides along track 192 along the ramps 57. Once the tissue 420 is
clamped, sealed and cut, end 95 clears edge 193 and movable handle
40 and flange 90 are redirected to exit pathway 58, where the
movable handle 40 returns to its unactuated position.
[0113] As mentioned above, the jaw members 110 and 120 may be
opened, closed and rotated to manipulate tissue 420 until sealing
is desired. This enables the user to position and re-position the
forceps 10 prior to activation and sealing. The end effector
assembly 100 is rotatable about longitudinal axis "A" through
rotation of the rotating assembly 80. It is envisioned that the
feed path of the cable lead 311 through the rotating assembly 80,
along shaft 12 and, ultimately, to the jaw member 110 enables the
user to rotate the end effector assembly 100 approximately 180
degrees in both the clockwise and counterclockwise directions
without tangling or causing undue strain on cable lead 311. As can
be appreciated, this facilitates the grasping and manipulation of
tissue 420.
[0114] Again as best shown in FIGS. 1 and 2, cutter lever 700
mounts adjacent movable handle 40 and cooperates with the knife
assembly 140 to selectively translate knife blade 185 through a
tissue seal 450.
[0115] Distal activation of the movable handle 40 (in the
embodiment shown in FIGS. 1 and 2) forces the cutter lever 700
distally, which, as explained in more detail below, ultimately
extends the knife blade 185 through the tissue 420. A knife spring
350 biases the knife assembly 70 in a retracted position such that
after severing tissue 420 the knife blade 185 and the knife
assembly 70 are automatically returned to a pre-firing
position.
[0116] Drive assembly 150 includes reciprocating sleeve 60, drive
housing 158, drive spring 67, drive ring 159, drive stop 155 and
guide sleeve 157 which all cooperate to form the drive assembly
150. More particularly and as best shown in FIGS. 22 and 23, the
reciprocating sleeve 60 includes a distal end 65 which as mentioned
above has an aperture 62 formed therein for actuating the detent
117 of jaw member 110. In one embodiment, the distal end 65
includes a scoop-like support member 69 for supporting a proximal
end 61 of the fixed jaw member 120 therein. The proximal end 61 of
the reciprocating sleeve 60 includes a slot 68 defined therein
which is dimensioned to slidingly support the knife assembly 70 for
longitudinal reciprocation thereof to sever tissue 420. The slot 68
also permits retraction of the reciprocating sleeve 60 over the
knife assembly 140 during the closing of jaw member 110 relative to
jaw member 120.
[0117] The proximal end 61 of the reciprocating sleeve 60 is
positioned within an aperture 151 in drive housing 158 to permit
selective reciprocation thereof upon actuation of the movable
handle 40. The drive spring 67 is assembled atop the drive housing
158 between a rear stop 156 of the drive housing 158 and a forward
stop 154 of the drive ring 159 such that movement of the forward
stop 154 compresses the drive spring 67 against the rear stop 156
which, in turn, reciprocates the drive sleeve 60. As a result
thereof, the jaw members 110 and 120 and the movable handle 40 are
biased by drive spring 67 in an open configuration. The drive stop
155 is fixedly positioned atop the drive housing 158 and biases the
movable handle 40 when actuated such that the drive flange 47
forces the stop 154 of the drive ring 159 proximally against the
force of the drive spring 67. The drive spring 67, in turn, forces
the rear stop 156 proximally to reciprocate the sleeve 60. In one
embodiment, the rotating assembly 80 is located proximal to the
drive flange 47 to facilitate rotation of the end effector assembly
100. The guide sleeve 157 mates with the proximal end 61 of the
reciprocating sleeve 60 and affixes to the drive housing 158. The
assembled drive assembly 150 is shown best in FIG. 14.
[0118] As best shown in FIGS. 12 and 15-18, the knife assembly 140
includes an elongated rod 182 having a bifurcated distal end
comprising prongs 182a and 182b which cooperate to receive a knife
bar 184 therein. The knife assembly 180 also includes a proximal
end 183 which is keyed to facilitate insertion into tube 160 of the
rotating assembly 80. A knife wheel 148 is secured to the knife bar
182 by a pin 143. More particularly, the elongated knife rod 182
includes apertures 181a and 181b which are dimensioned to receive
and secure the knife wheel 148 to the knife rod 182 such that
longitudinal reciprocation of the knife wheel 148, in turn, moves
the elongated knife rod 182 to sever tissue 420.
[0119] In one embodiment, the knife wheel 148 is donut-like and
includes rings 141a and 141b which define a drive slot 147 designed
to receive a drive bar (not shown) such that actuation of the
movable handle 40 forces the drive bar and the knife wheel 148
distally. It is envisioned that apertures 181a and 181b may be used
for different configurations. As such, pin 143 is designed for
attachment through either aperture 181a or 181b to mount the knife
wheel 148 (see FIG. 18). Knife wheel 148 also includes a series of
radial flanges 142a and 142b which are dimensioned to slide along
both channel 163 of tube 160 and slot 68 of the reciprocating
sleeve 60 (see FIG. 9).
[0120] As mentioned above, the knife rod 182 is dimensioned to
mount the knife bar 184 between prongs 182a and 182b, which can be
in a friction-fit engagement. The knife bar 184 includes a series
of steps 186a, 186b and 186c which reduce the profile of the knife
bar 184 towards the distal end thereof. The distal end of the knife
bar 184 includes a knife support 188 which is dimensioned to retain
knife blade 185. The end of the knife support 188 can include a
chamfered edge 188a. It is envisioned that the knife blade 185 may
be welded to the knife support 188 or secured in any manner known
in the trade.
[0121] As best shown in FIGS. 1 and 2, as the tissue is securely
grasped and the cutter lever 700 advances distally due to actuation
of movable handle 40, switch 500 activates, by virtue of movable
handle 40 engaging contact 502. At this point, electrosurgical
energy is transferred through cable leads to jaw members 110 and
120, as described in commonly-assigned, co-pending U.S. application
Ser. No. 10/460,926 entitled "VESSEL SEALER AND DIVIDER FOR USE
WITH SMALL TROCARS AND CANNULAS" by Dycus et al., which is hereby
incorporated by reference in its entirety herein. As can be
appreciated from the mechanics of the forceps 10, the switch 500
cannot fire unless the jaw members 110 and 120 are closed. A sensor
(not shown) may be included in the generator or the housing which
prevents activation unless the jaw members 110 and 120 have tissue
420 held therebetween. In addition, other sensor mechanisms may be
employed which determine pre-surgical, concurrent surgical (i.e.,
during surgery) and/or post surgical conditions. The sensor
mechanisms may also be utilized with a closed-loop feedback system
coupled to the electrosurgical generator to regulate the
electrosurgical energy based upon one or more pre-surgical,
concurrent surgical or post surgical conditions. Various sensor
mechanisms and feedback systems are described in commonly-owned,
co-pending U.S. patent application Ser. No. 10/427,832 entitled
"METHOD AND SYSTEM FOR CONTROLLING OUTPUT OF RF MEDICAL GENERATOR"
filed on May 1, 2003 the entire contents of which are hereby
incorporated by reference herein.
[0122] In one embodiment, the jaw members 110 and 120 are
electrically isolated from one another such that electrosurgical
energy can be effectively transferred through the tissue 420 to
form seal 450. For example and as best illustrated in FIGS. 24 and
25, each jaw member, e.g., 110, includes a uniquely-designed
electrosurgical cable path disposed therethrough which transmits
electrosurgical energy to the electrically conductive sealing
surface 112. It is envisioned that jaw member 110 may include one
or more cable guides or crimp-like electrical connectors to direct
cable lead 311 towards electrically conductive sealing surface 112.
In one embodiment, cable lead 311 is held loosely but securely
along the cable path to permit rotation of the jaw member 110 about
pivot 103. As can be appreciated, this isolates electrically
conductive sealing surface 112 from the remaining operative
components of the end effector assembly 100, jaw member 120 and
shaft 12. The second electrical potential is conducted to jaw
member 120 through tube 160. The two potentials are isolated from
one another by virtue of the insulative sheathing surrounding cable
lead 311.
[0123] It is contemplated that utilizing a cable feed path for
cable lead 311 and by utilizing a conductive tube 160 to carry the
first and second electrical potentials not only electrically
isolates each jaw member 110 and 120 but also allows the jaw
members 110 and 120 to pivot about pivot pin 103 without unduly
straining or possibly tangling cable lead 311. Moreover, it is
envisioned that the simplicity of the electrical connections
greatly facilitates the manufacturing and assembly process and
assures a consistent and tight electrical connection for the
transfer of energy through the tissue 420.
[0124] As discussed in commonly-assigned, co-pending U.S.
application Ser. No. 10/460,926 entitled "VESSEL SEALER AND DIVIDER
FOR USE WITH SMALL TROCARS AND CANNULAS" by Dycus et al., which is
hereby incorporated by reference in its entirety herein, it is
envisioned that select cable leads are fed through halves 82a and
82b of the rotating assembly 80 in such a manner to allow rotation
of the shaft 12 (via rotation of the rotating assembly 80) in the
clockwise or counter-clockwise direction without unduly tangling or
twisting the cable leads. More particularly, select cable leads are
fed through a series of conjoining slots 84a, 84b, 84c and 84d
located in the two halves 82a and 82b of the rotating assembly 80.
In one embodiment, each conjoining pair of slots, e.g., 84a, 84b
and 84c, 84d, is large enough to permit rotation of the rotating
assembly 80 without unduly straining or tangling the cable leads.
The presently disclosed cable lead feed path is envisioned to allow
rotation of the rotation assembly approximately 180 degrees in
either direction.
[0125] Turning back to FIGS. 1-3 which show a view of the housing
20, rotating assembly 80, movable handle 40, fixed handle 50, latch
assembly 600, switch 500 and cutter lever 700, it is envisioned
that all of these various component parts along with the shaft 12
and the end effector assembly 100 are assembled during the
manufacturing process to form a partially and/or fully disposable
forceps 10. For example and as mentioned above, the shaft 12 and/or
end effector assembly 100 may be disposable and, therefore,
selectively/releasably engagable with the housing 20 and rotating
assembly 80 to form a partially disposable forceps 10 and/or the
entire forceps 10 may be disposable after use.
[0126] Once assembled, drive spring 67 is poised for compression
atop drive housing 158 upon actuation of the movable handle 40.
More particularly, movement of the movable handle 40 about pivot
point 29 reciprocates the flange 90 into fixed handle 50 and forces
drive flange 47 against flange 154 of drive ring 159 to compress
drive spring 67 against the rear stop 156 to reciprocate the sleeve
60 (see FIG. 28).
[0127] The switch 500 is prevented from firing before the tissue
420 is clamped by jaw members 110 and 120. For the sealing to take
place, the movable handle 40 should be actuated far enough to
contact (or, alternatively, for the cutter lever 700 to contact)
the switch 500, contact 502 or a sensor (not shown). Before the
switch 500 is contacted, the movable handle 40 should travel
sufficiently far enough to cause jaw members 110 and 120 to be
clamped. It is envisioned that the opposing jaw members 110 and 120
may be rotated and partially opened and closed before activation of
switch 500 which, as can be appreciated, allows the user to grip
and manipulate the tissue 420 before the tissue 420 is sealed.
[0128] It is envisioned that configuring the pivot 29 above or
relative to a longitudinal axis defined through the shaft provides
an increased mechanical advantage, thus facilitating and easing
selective compression of the drive spring 67 a specific distance
which, in turn, imparts a specific load on the reciprocating sleeve
60. As best seen in FIG. 2, the moveable handle 40 includes a drive
cam surface 49' which is designed in-line with the longitudinal
axis "A," which together with the position of the pivot 28 being
disposed above axis "A," increase the mechanical advantage of the
movable handle 40 and reduce the amount of force necessary to
actuate the jaw members 110, 120 with the preferred closure force.
The load of the reciprocating sleeve 60 is converted to a torque
about the jaw pivot 103. As a result, a specific closure force can
be transmitted to the opposing jaw members 110 and 120 between the
range of about 3 kg/cm.sup.2 to about 16 kg/cm.sup.2. As mentioned
above, the jaw members 110 and 120 may be opened, closed and
rotated to manipulate tissue 420 until sealing is desired. This
enables the user to position and re-position the forceps 10 prior
to activation and sealing.
[0129] Once the desired position for the sealing site is determined
and the jaw members 110 and 120 are properly positioned, movable
handle 40 may be actuated farther such that the switch 500 is
engaged to seal the tissue 420 with electrosurgical energy.
Continued actuation of movable handle 40 engages knife assembly 140
(as discussed above), which causes the tissue seal 450 to be
severed.
[0130] It is envisioned that the end effector assembly 100 and/or
the jaw members 110 and 120 may be dimensioned to off-load some of
the excessive clamping forces to prevent mechanical failure of
certain internal operating elements of the end effector 100.
[0131] As can be appreciated, the combination of the increased
mechanical advantage provided by the above-the-axis pivot 29 along
with the compressive force associated with the drive spring 67
facilitate and assure consistent, uniform and accurate closure
pressure about the tissue 420 within the desired working pressure
range of about 3 kg/cm.sup.2 to about 16 kg/cm.sup.2 and,
preferably, about 7 kg/cm.sup.2 to about 13 kg/cm.sup.2. By
controlling the intensity, frequency and duration of the
electrosurgical energy applied to the tissue 420, the user can
effectively seal tissue.
[0132] In one embodiment, the electrically conductive sealing
surfaces 112 and 122 of the jaw members 110 and 120, respectively,
are relatively flat to avoid current concentrations at sharp edges
and to avoid arcing between high points. In addition and due to the
reaction force of the tissue 420 when engaged, jaw members 110 and
120 can be manufactured to resist bending.
[0133] For example, the jaw members 110 and 120 may be tapered
along the width thereof which is advantageous for two reasons: 1)
the taper will apply constant pressure for a constant tissue
thickness at parallel; 2) the thicker proximal portion of the jaw
members 110 and 120 will resist bending due to the reaction force
of the tissue 420.
[0134] As mentioned above, at least one jaw member, e.g., 120, may
include a stop member 750 which limits the movement of the two
opposing jaw members 110 and 120 relative to one another. In one
embodiment, the stop member 750 extends a predetermined distance
from the sealing surface 122 (according to the specific material
properties [e.g., compressive strength, thermal expansion, etc.])
to yield a consistent and accurate gap distance "G" during sealing
(FIG. 29). The gap distance between opposing sealing surfaces 112
and 122 during sealing ranges from about 0.001 inches to about
0.006 inches and, desirably, between about 0.002 and about 0.003
inches. It is envisioned that the non-conductive stop members 750
may be molded onto the jaw members 110 and 120 (e.g., overmolding,
injection molding, etc.), stamped onto the jaw members 110 and 120
or deposited (e.g., deposition) onto the jaw members 110 and 120.
For example, one technique involves thermally spraying a ceramic
material onto the surface of the jaw member 110 and 120 to form the
stop members 750. Several thermal spraying techniques are
contemplated which involve depositing a broad range of heat
resistant and insulative materials on various surfaces to create
stop members 750 for controlling the gap distance between
electrically conductive surfaces 112 and 122.
[0135] As energy is being selectively transferred to the end
effector assembly 100, across the jaw members 110 and 120 and
through the tissue 420, a tissue seal 450 forms isolating two
tissue halves 420a and 420b. With other known vessel sealing
instruments, the user then removes and replaces the forceps 10 with
a cutting instrument (not shown) or manually activates another
switch to divide the tissue halves 420a and 420b along the tissue
seal 450. As can be appreciated, this is both time consuming and
tedious and may result in inaccurate tissue division across the
tissue seal 450 due to misalignment or misplacement of the cutting
instrument along the ideal tissue cutting plane.
[0136] As explained in detail above, the present disclosure
incorporates a knife assembly 140 which, when activated via the
handle assembly 30, progressively and selectively divides the
tissue 420 along an ideal tissue plane in precise manner to
effectively and reliably divide the tissue 420 into two sealed
halves 420a and 420b with a tissue gap 475 therebetween (see FIG.
33). The knife assembly 140 in conjunction with the handle assembly
30 allows the user to quickly separate the tissue 420 immediately
after sealing without substituting a cutting instrument through a
cannula or trocar port and without having to perform a different
action (e.g., manually activating a switch or pulling a trigger).
As can be appreciated, accurate sealing and dividing of tissue 420
is accomplished with a single, continuous motion using the same
forceps 10.
[0137] It is envisioned that knife blade 185 may also be coupled to
the same or an alternative electrosurgical energy source to
facilitate separation of the tissue 420 along the tissue seal 450
(not shown). Moreover, it is envisioned that the angle of the tip
of the knife blade 185 may be dimensioned to provide more or less
aggressive cutting angles depending upon a particular purpose. For
example, the knife blade 185 may be positioned at an angle which
reduces "tissue wisps" associated with cutting. Moreover, the knife
blade 185 may be designed having different blade geometries such as
serrated, notched, perforated, hollow, concave, convex etc.
depending upon a particular purpose or to achieve a particular
result.
[0138] From the foregoing and with reference to the various figure
drawings, those skilled in the art will appreciate that certain
modifications can also be made to the present disclosure without
departing from the scope of the same. For example, it may be
preferable to add other features to the forceps 10, e.g., an
articulating assembly to axially displace the end effector assembly
100 relative to the elongated shaft 12.
[0139] It is also contemplated that the forceps 10 (and/or the
electrosurgical generator used in connection with the forceps 10)
may include a sensor or feedback mechanism (not shown) which
automatically selects the appropriate amount of electrosurgical
energy to effectively seal the particularly-sized tissue grasped
between the jaw members 110 and 120. The sensor or feedback
mechanism may also measure the impedance across the tissue during
sealing and provide an indicator (visual and/or audible) that an
effective seal has been created between the jaw members 110 and
120. Examples of such sensor systems are described in
commonly-owned U.S. patent application Ser. No. 10/427,832 entitled
"METHOD AND SYSTEM FOR CONTROLLING OUTPUT OF RF MEDICAL GENERATOR,"
filed on May 1, 2003 the entire contents of which are hereby
incorporated by reference herein.
[0140] Although the figures depict the forceps 10 manipulating an
isolated vessel 420, it is contemplated that the forceps 10 may be
used with non-isolated vessels as well. Other cutting mechanisms
are also contemplated to cut tissue 420 along the ideal tissue
plane.
[0141] It is envisioned that the outer surface of the end effector
assembly 100 may include a nickel-based material, coating,
stamping, metal injection molding which is designed to reduce
adhesion between the jaw members 110 and 120 with the surrounding
tissue during activation and sealing. Moreover, it is also
contemplated that the conductive surfaces 112 and 122 of the jaw
members 110 and 120 may be manufactured from one (or a combination
of one or more) of the following materials: nickel-chrome, chromium
nitride, MedCoat 2000 manufactured by The Electrolizing Corporation
of OHIO, inconel 600 and tin-nickel. The tissue conductive surfaces
112 and 122 may also be coated with one or more of the above
materials to achieve the same result, i.e., a "non-stick surface."
As can be appreciated, reducing the amount that the tissue "sticks"
during sealing improves the overall efficacy of the instrument.
[0142] One particular class of materials disclosed herein has
demonstrated superior non-stick properties and, in some instances,
superior seal quality. For example, nitride coatings which include,
but not are not limited to: TiN, ZrN, TiAIN, and CrN are preferred
materials used for non-stick purposes. CrN has been found to be
particularly useful for non-stick purposes due to its overall
surface properties and optimal performance. Other classes of
materials have also been found to reducing overall sticking. For
example, high nickel/chrome alloys with a Ni/Cr ratio of
approximately 5:1 have been found to significantly reduce sticking
in bipolar instrumentation. One particularly useful non-stick
material in this class is Inconel 600. Bipolar instrumentation
having sealing surfaces 112 and 122 made from or coated with Ni200,
Ni201 (.about.100% Ni) also showed improved non-stick performance
over typical bipolar stainless steel electrodes.
[0143] While several embodiments of the disclosure have been shown
in the figures, it is not intended that the disclosure be limited
thereto, as it is intended that the disclosure be as broad in scope
as the art will allow and that the specification be read likewise.
Therefore, the above description should not be construed as
limiting, but merely as exemplifications of preferred embodiments.
Those skilled in the art will envision other modifications within
the scope and spirit of the claims appended hereto.
* * * * *