U.S. patent application number 11/246384 was filed with the patent office on 2006-04-13 for feedback mechanism for use with an ultrasonic surgical instrument.
Invention is credited to Craig N. Faller, Kevin L. Houser, Steven K. Neuenfeldt, Mark A. Neurohr.
Application Number | 20060079877 11/246384 |
Document ID | / |
Family ID | 36148984 |
Filed Date | 2006-04-13 |
United States Patent
Application |
20060079877 |
Kind Code |
A1 |
Houser; Kevin L. ; et
al. |
April 13, 2006 |
Feedback mechanism for use with an ultrasonic surgical
instrument
Abstract
An ultrasonic clamp coagulator assembly that is configured to
permit selective cutting, coagulation and clamping of tissue during
surgical procedures. An elongated portion of the instrument can be
configured for endoscopic applications and has an outside diameter
of less than 6 mm. The construction includes a clamping mechanism,
including a clamp arm pivotally mounted at the distal portion of
the instrument, which is specifically configured to create a
desired level of tissue clamping forces, exceeding 4 pounds when
the trigger is fully closed. The clamping mechanism includes a
two-piece pad design and pad material that enables the higher
tissue clamping forces and a force-limiting mechanism that
effectively smooths out abusive tissue forces. The assembly also
features hand activation configured to provide an ergonomical grip
and operation for the surgeon. Hand switches are placed in the
range of the natural swing of the surgeon's thumb, whether gripping
the surgical instrument right-handed or left handed.
Inventors: |
Houser; Kevin L.;
(Springboro, OH) ; Neuenfeldt; Steven K.;
(Pleasanton, CA) ; Neurohr; Mark A.; (Newport,
KY) ; Faller; Craig N.; (Milford, OH) |
Correspondence
Address: |
PHILIP S. JOHNSON;JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
36148984 |
Appl. No.: |
11/246384 |
Filed: |
October 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60617427 |
Oct 8, 2004 |
|
|
|
60676709 |
May 2, 2005 |
|
|
|
Current U.S.
Class: |
606/40 |
Current CPC
Class: |
A61B 2017/320094
20170801; A61B 2017/2845 20130101; A61B 2017/2911 20130101; A61B
2017/00353 20130101; A61B 2017/00424 20130101; Y10T 29/49998
20150115; A61B 17/320092 20130101; A61B 2017/320095 20170801; Y10T
29/49005 20150115; A61B 17/2909 20130101; A61B 2017/2825
20130101 |
Class at
Publication: |
606/040 |
International
Class: |
A61B 18/18 20060101
A61B018/18 |
Claims
1. An ultrasonic clamp coagulator apparatus comprising: a housing
comprising an actuator having a first open position and a second
closed position; a tube having a proximal end joined to the
housing, and a distal end; an ultrasonic waveguide having a
proximal end and a distal end and further positioned within the
outer tube; an ultrasonically actuated blade attached to the distal
end of the waveguide; a clamp member pivotable with respect to the
blade for clamping tissue between the clamp member and the blade;
and a feedback element for providing an indication that the
actuator is in the closed position.
2. The ultrasonic clamp coagulator apparatus in accordance with
claim 1, wherein the feedback element provides an audible
indication.
3. The ultrasonic clamp coagulator apparatus in accordance with
claim 1, wherein the feedback element provides a tactile
indication.
4. The ultrasonic clamp coagulator apparatus in accordance with
claim 1, wherein the feedback element is operatively attached to
the actuator.
5. The ultrasonic clamp coagulator apparatus in accordance with
claim 1, wherein the feedback element is operatively attached to
the housing.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the priority benefit of U.S.
provisional patent application Ser. Nos. 60/617,427, filed on Oct.
8, 2004, and 60/676,709, filed on May 2, 2005, both of which are
incorporated herein by reference.
[0002] This application contains subject matter that relates to and
incorporates by reference in their entirety, for any and all
purposes, the following non-provisional applications: [0003] TISSUE
PAD FOR USE WITH AN ULTRASONIC SURGICAL INSTRUMENT, Ser. No.
______, filed Oct. 7, 2005; [0004] COMBINATION TISSUE PAD FOR USE
WITH AN ULTRASONIC SURGICAL INSTRUMENT, Ser. No. ______, filed Oct.
7, 2005; [0005] ACTUATION MECHANISM FOR USE WITH AN ULTRASONIC
SURGICAL INSTRUMENT, Ser. No. ______, filed Oct. 7, 2005; [0006]
CLAMP MECHANISM FOR USE WITH AN ULTRASONIC SURGICAL INSTRUMENT,
Ser. No. ______, filed Oct. 7, 2005; [0007] HANDLE ASSEMBLY HAVING
HAND ACTIVATION FOR USE WITH AN ULTRASONIC SURGICAL INSTRUMENT,
Ser. No. ______, filed Oct. 7, 2005; [0008] ULTRASONIC SURGICAL
SHEARS AND TISSUE PAD FOR SAME, Ser. No. 11/065,378, filed Feb. 24,
2005; and [0009] HAND ACTIVATED ULTRASONIC INSTRUMENT, Ser. No.
10/869,351, filed Jun. 16, 2004.
FIELD OF THE INVENTION
[0010] The present invention relates, in general, to ultrasonic
surgical instruments and, more particularly, to an ultrasonic
surgical clamp coagulator apparatus particularly configured to
provide increased tissue transaction forces.
BACKGROUND OF THE INVENTION
[0011] Ultrasonic surgical instruments are finding increasingly
widespread applications in surgical procedures by virtue of the
unique performance characteristics of such instruments. Depending
upon specific instrument configurations and operational parameters,
ultrasonic surgical instruments can provide substantially
simultaneous cutting of tissue and homeostasis by coagulation,
desirably minimizing patient trauma. The cutting action is
typically effected by an end-effector at the distal end of the
instrument, which transmits ultrasonic energy to tissue brought
into contact with the end-effector. Ultrasonic instruments of this
nature can be configured for open surgical use, laparoscopic or
endoscopic surgical procedures including robotic-assisted
procedures.
[0012] Ultrasonic surgical instruments have been developed that
include a clamp mechanism to press tissue against the blade of the
end-effector in order to couple ultrasonic energy to the tissue of
a patient. Such an arrangement (sometimes referred to as a clamp
coagulator shears or an ultrasonic transector) is disclosed in U.S.
Pat. Nos. 5,322,055; 5,873,873 and 6,325,811, all of which are
incorporated herein by reference. The surgeon activates the clamp
arm to press the clamp pad against the blade by squeezing on the
handgrip or handle.
[0013] Some current ultrasonic shears devices, however, have the
tendency to create tissue tags. Tissue tags are the tissue that
remains clamped in the jaw that is not transected after the
majority of the tissue in the jaw has been transected and falls
away. Tissue tags may result from insufficient end-effector
proximal loading and/or lower proximal blade activity. Surgeons may
mitigate tissue tags either through the addition of vertical
tension (i.e. putting tension on the tissue using the blade) or
rearward traction on the device in order to move the untransected
tissue to a more active portion of the blade to complete the
cut.
[0014] Some current ultrasonic shears devices utilize tissue pads
that close in parallel with the surface of the blade. This presents
certain problems in terms of the pressure profile exerted on the
tissue. As tissue is compressed between the jaw and the blade, the
proximal portion of the blade defelcts under load more than the
proximal portion of the clamp arm moves in applying the load
against the blade. This deflection is in part created by the
portion of the blade distal to the most distal node of the device.
It is also partly created by the deflection of the transmission rod
proximal to the most distal node. Additionally, the fact that blade
amplitude decreases moving proximal of the tip of the blade makes
the situation worse since the amount of energy transferred to the
tissue, even if the pressure was constant, is reduced.
[0015] Current tissue pad designs utilize PTFE material to contact
the tissue and blade. Although these designs have been adequate,
they tend to suffer from longevity issues since the pads tend to
deteriorate over long surgical procedures. Additionally, newer
designs of clamp coagulator shears increase blade amplitude and/or
the loading of the pad against the tissue and blade and overwhelm
the pad material, resulting in less than required tissue pad life.
The pad material limits the amount of force that may be applied
against the tissue and blade, which in turn limits the tissue
thickness or vessel size that some current clamp coagulator shears
may effectively cut and coagulate.
[0016] Some current designs of clamp coagulator shears utilize an
inner tube within an outer tube concept to drive the clamp arm open
and close. During surgical procedures the clamp arm may be
subjected to axial clamp forces exceeding 2.5 pounds and/or
torsional abuse loads and may cause the clamp arm to disengage from
the inner tube or completely from the shears.
[0017] Some current designs of clamp coagulator shears utilize a
constant force spring mechanism that prevents the application of
too much force to the clamp arm and blade. Although the mechanism
provides relatively constant force to the system, the spring
imparts some slope to the force curve. In applications where the
clamp force is low, the slope is not significant. In applications
with high clamp forces, however, the difference in force
attributable to the slope over the possible range of spring
compressions becomes very significant and may exceed the maximum
force allowable in the blade, in the tube assemblies or in other
components of the system. The high slope could allow the maximum
force to be exceeded under abuse modes or through normal
manufacturing tolerance variations. If this occurs the blade may
bend, the actuation mechanism may fail or undesirable tissue
effects may occur (i.e. fast cutting, but minimal tissue
coagulation). This situation is aggravated by the fact that the jaw
(the clamp arm and pad) of the device can meet sufficient
resistance to engage the force limiting mechanism when the jaw
almost contacts the blade (when transecting thin tissue or at the
end of the transaction or clamping solid objects such as other
devices) or when the jaw is still open (when transecting thick
tissue).
[0018] Some current designs of clamp coagulator shears utilize
force-limiting springs to ensure that clamp forces are within a
specified range. It is also necessary for the force-limiting spring
design to allow the surgeon to "feather" (apply less than the
maximum force and slowly increase to the maximum force). In these
mechanisms, therefore, the jaws close until a predetermined force
is met and then the additional stroke drives the mechanism into the
force limiting range. In some cases, though, the surgeon may,
unknowingly, fail to apply the full force of the jaw against the
tissue resulting in incomplete tissue cuts or insufficient
coagulation. Alternatively, the surgeon may unknowingly release
full force of the jaw against the tissue during a transaction that
results in incomplete tissue cuts or insufficient coagulation.
[0019] Some current designs of clamp coagulator shears utilize a
foot pedal to energize the surgical instrument. The surgeon
operates the foot pedal while simultaneously applying pressure to
the handle to press tissue between the jaw and blade to activate a
generator that provides energy that is transmitted to the cutting
blade for cutting and coagulating tissue. Key drawbacks with this
type of instrument activation include the loss of focus on the
surgical field while the surgeon searches for the foot pedal, the
foot pedal getting in the way of the surgeon's movement during a
procedure and surgeon leg fatigue during long cases.
[0020] Some current designs of clamp coagulator shears have
eliminated the foot pedal and provided hand activation on a
stationary trigger. This may be cumbersome, especially for surgeons
with large hands.
[0021] Some current designs of clamp coagulator utilize handles
that are either of a pistol or scissors grips design. The scissor
grip designs may have one thumb or finger grip that is immovable
and fixed to the housing and one movable thumb or finger grip. This
type of grip may not be entirely familiar to surgeons who use other
open-type surgical instruments, such as hemostats, where both thumb
and finger grips move in opposition to one another.
[0022] It would be desirable to provide an ultrasonic surgical
instrument that overcomes some of the deficiencies of current
instruments. The ultrasonic surgical instrument described herein
overcomes those deficiencies.
BRIEF SUMMARY OF THE INVENTION
[0023] An ultrasonic clamp coagulator assembly embodying the
principles of the present invention is configured to permit
selective cutting, coagulation and clamping of tissue during
surgical procedures. An elongated portion of the instrument can be
configured for endoscopic applications and has an outside diameter
of less than 6 mm. The construction includes a clamping mechanism,
including a clamp arm pivotally mounted at the distal portion of
the instrument, which is specifically configured to create a
desired level of tissue clamping forces, exceeding 4 pounds when
the trigger is fully closed, notwithstanding the relatively small
cross-section of the elongated portion.
[0024] The clamping mechanism also includes a pad design and pad
material that enables the higher tissue clamping forces.
[0025] The clamp coagulator device also includes a force-limiting
mechanism that effectively smooths out abusive tissue forces.
[0026] The clamp coagulator device also features hand activation
configured in such a way to provide an ergonomically pleasing grip
and operation for the surgeon. Hand switches are be placed in the
range of the natural swing of the surgeon's thumb, whether gripping
surgical instrument right-handed or left handed.
BRIEF DESCRIPTION OF THE FIGURES
[0027] The novel features of the invention are set forth with
particularity in the appended claims. The invention itself,
however, both as to organization and methods of operation, may best
be understood by reference to the following description, taken in
conjunction with the accompanying drawings in which:
[0028] FIG. 1 is a perspective view illustrating an embodiment of
an ultrasonic surgical instrument in accordance with the present
invention;
[0029] FIG. 2 is a perspective assembly view of an embodiment of an
ultrasonic surgical instrument in accordance with the present
invention;
[0030] FIG. 3a is a perspective assembly view of the clamp arm and
tissue pads;
[0031] FIG. 3b is an elevation section view of the clamp arm and
"T" groove;
[0032] FIG. 3c is an elevation section view of the clamp arm and
dovetail groove;
[0033] FIG. 3d is a perspective view of the tissue pads aligned and
staked within the clamp arm;
[0034] FIG. 3e is an elevation view of the clamp arm illustrating
the tapered profile;
[0035] FIG. 3f is a top plan view of the clamp arm;
[0036] FIG. 4a is a perspective assembly view of the blade, clamp
arm, tissue pads and actuator tube with the clamp arm in the closed
position;
[0037] FIG. 4b is a perspective assembly view of the blade, clamp
arm, tissue pads and actuator tube with the clamp arm in the open
position;
[0038] FIG. 4c is a schematic of a clamp arm in accordance with the
present invention illustrating force calculations;
[0039] FIG. 5 is a cutaway elevation view of the housing portion of
an ultrasonic surgical instrument in accordance with an embodiment
of the present invention illustrating force-limiting springs and
clamp closure detent mechanism and partial cutaway elevation view
of the transmission rod and end effector;
[0040] FIG. 6a is an exploded view of the housing illustrating the
thumb actuation buttons and switch assembly and linkage of the
finger grip clamp actuator;
[0041] FIG. 6b is an exploded view of the housing with the switch
assembly removed for clarity;
[0042] FIG. 7 is a perspective assembly view of the switch assembly
and electrical ring contactors;
[0043] FIG. 8a is a perspective assembly view of the switch
assembly and electrical ring contactors;
[0044] FIG. 8b is a perspective view of the proximal end of the
transducer illustrating conductor rings;
[0045] FIG. 8c is an electrical schematic of the pushbutton
circuit;
[0046] FIG. 9 is a perspective view of an ultrasonic surgical
instrument with a cut away view of the housing and connected to a
transducer;
[0047] FIG. 10 is a perspective view of an ultrasonic surgical
instrument with the trigger extended distally and the clamp arm in
the open position;
[0048] FIG. 11 is a perspective view of an ultrasonic surgical
instrument with the trigger retracted proximally and the clamp arm
in the closed position;
[0049] FIG. 12 is an elevation view of a left-handed grip of an
embodiment of an ultrasonic surgical instrument in accordance with
the present invention;
[0050] FIG. 13 is an elevation view of a left-handed grip of an
ultrasonic surgical instrument in accordance with an embodiment of
the present invention with the index finger accessing the rotation
wheel;
[0051] FIG. 14 is an elevation view of a left-handed grip of an
ultrasonic surgical instrument in accordance with the present
invention with the thumb accessing a first activation button;
[0052] FIG. 15 is an elevation view of a left-handed grip of an
ultrasonic surgical instrument in accordance with the present
invention with the thumb accessing a second activation button;
[0053] FIG. 16a-c are force curves illustrating various forces as a
function of the trigger position and tissue conditions;
[0054] FIG. 17 is an elevation view of the surgical instrument with
graphical illustrations of the surgeon finger placement;
[0055] FIG. 18 is a perspective assembly view of a second
embodiment of an ultrasonic surgical instrument in accordance with
the present invention;
[0056] FIG. 19 is an exploded view of a handpiece connector;
[0057] FIGS. 20a-b are exploded views of a large slip ring and a
small slip ring, respectively;
[0058] FIG. 21 is an exploded view of the flex circuit
apparatus
[0059] FIG. 22 is an electrical schematic of the flex circuit of
FIG. 21
[0060] FIG. 23 is an elevation view of a surgical instrument in
accordance with one aspect of the invention; and
[0061] FIG. 24 is a perspective view of a surgical instrument in an
alternate aspect of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0062] Before explaining the present invention in detail, it should
be noted that the invention is not limited in its application or
use to the details of construction and arrangement of parts
illustrated in the accompanying drawings and description. The
illustrative embodiments of the invention may be implemented or
incorporated in other embodiments, variations and modifications,
and may be practiced or carried out in various ways. Further,
unless otherwise indicated, the terms and expressions employed
herein have been chosen for the purpose of describing the
illustrative embodiments of the present invention for the
convenience of the reader and are not for the purpose of limiting
the invention.
[0063] Further, it is understood that any one or more of the
following-described embodiments, expressions of embodiments,
examples, etc. can be combined with any one or more of the other
following-described embodiments, expressions of embodiments,
examples, etc.
[0064] The present invention is particularly directed to an
improved ultrasonic surgical clamp coagulator apparatus which is
configured for effecting tissue cutting, coagulation, and/or
clamping during surgical procedures. The present apparatus can be
readily configured for use in open surgical procedures, as well as
laparoscopic or endoscopic procedures and robot-assisted surgical
procedures. Versatile use is facilitated by selective use of
ultrasonic energy. When ultrasonic components of the apparatus are
inactive, tissue can be readily gripped and manipulated, as
desired, without tissue cutting or damage. When the ultrasonic
components are activated, the apparatus permits tissue to be
gripped for coupling with the ultrasonic energy to effect tissue
coagulation, with application of increased pressure efficiently
effecting tissue cutting and coagulation. If desired, ultrasonic
energy can be applied to tissue without use of the clamping
mechanism of the apparatus by appropriate manipulation of the
ultrasonic blade.
[0065] As will become apparent from the following description, the
present clamp coagulator apparatus is particularly configured for
disposable use by virtue of its straightforward construction. As
such, it is contemplated that the apparatus be used in association
with an ultrasonic generator unit of a surgical system, whereby
ultrasonic energy from the generator unit provides the desired
ultrasonic actuation for the present clamp coagulator apparatus. It
will be appreciated that a clamp coagulator apparatus embodying the
principles of the present invention can be configured for
non-disposable or multiple use, and non-detachably integrated with
an associated ultrasonic generator unit. However, detachable
connection of the present clamp coagulator apparatus with an
associated ultrasonic generator unit is presently preferred for
single-patient use of the apparatus.
[0066] The present invention will be described in combination with
an ultrasonic instrument as described herein. Such description is
exemplary only, and is not intended to limit the scope and
applications of the invention. For example, the invention is useful
in combination with a multitude of ultrasonic instruments including
those described in, for example, U.S. Pat. Nos. 5,938,633;
5,935,144; 5,944,737; 5,322,055, 5,630,420; and 5,449,370.
[0067] With reference to FIGS. 1-3, an embodiment of a surgical
system 19, including an ultrasonic surgical instrument 100 in
accordance with the present invention is illustrated. The surgical
system 19 includes an ultrasonic generator 30 connected to an
ultrasonic transducer 50 via cable 22, and an ultrasonic surgical
instrument 100. It will be noted that, in some applications, the
ultrasonic transducer 50 is referred to as a "hand piece assembly"
because the surgical instrument of the surgical system 19 is
configured such that a surgeon may grasp and manipulate the
ultrasonic transducer 50 during various procedures and operations.
A suitable generator is the GEN 300 sold by Ethicon Endo-Surgery,
Inc. of Cincinnati, Ohio.
[0068] The ultrasonic surgical instrument 100 includes a
multi-piece handle assembly 68 adapted to isolate the operator from
the vibrations of the acoustic assembly contained within transducer
50. The handle assembly 68 can be shaped to be held by a user in a
conventional manner, but it is contemplated that the present
ultrasonic surgical instrument 100 principally be grasped and
manipulated by a trigger-like arrangement provided by a handle
assembly of the instrument, as will be described. While multi-piece
handle assembly 68 is illustrated, the handle assembly 68 may
comprise a single or unitary component. The proximal end of the
ultrasonic surgical instrument 100 receives and is fitted to the
distal end of the ultrasonic transducer 50 by insertion of the
transducer into the handle assembly 68. The ultrasonic surgical
instrument 100 may be attached to and removed from the ultrasonic
transducer 50 as a unit. The ultrasonic surgical instrument 100 may
include a handle assembly 68, comprising mating housing portion 69,
housing portion 70, and a transmission assembly 71. When the
present instrument is configured for endoscopic use, the
construction can be dimensioned such that transmission assembly 71
has an outside diameter of approximately 5.5 mm. The elongated
transmission assembly 71 of the ultrasonic surgical instrument 100
extends orthogonally from the instrument handle assembly 68. The
transmission assembly 71 can be selectively rotated with respect to
the handle assembly 68 as further described below. The handle
assembly 68 may be constructed from a durable plastic, such as
polycarbonate or a liquid crystal polymer. It is also contemplated
that the handle assembly 68 may alternatively be made from a
variety of materials including other plastics, ceramics or
metals.
[0069] The transmission assembly 71 may include an outer tubular
member or outer sheath 72, an inner tubular actuating member 76, a
waveguide 80 and end-effector 81 (blade 79, clamp arm 56 and one or
more clamp pads 58). As will be described, the outer sheath 72, the
actuating member 76, and the waveguide or transmission rod 80 may
be joined together for rotation as a unit (together with ultrasonic
transducer 50) relative to handle assembly 68. The waveguide 80,
which is adapted to transmit ultrasonic energy from transducer 50
to blade 79 may be flexible, semi-flexible or rigid. The waveguide
80 may also be configured to amplify the mechanical vibrations
transmitted through the waveguide 80 to the blade 79 as is well
known in the art. The waveguide 80 may further have features to
control the gain of the longitudinal vibration along the waveguide
80 and features to tune the waveguide 80 to the resonant frequency
of the system. In particular, waveguide 80 may have any suitable
cross-sectional dimension. For example, the waveguide 80 may have a
substantially uniform cross-section or the waveguide 80 may be
tapered at various sections or may be tapered along its entire
length. In one expression of the current embodiment, the waveguide
diameter is about 0.113 inches nominal to minimize the amount of
deflection at the blade 79 so that gapping in the proximal portion
of the end effector 81 is minimized.
[0070] Ultrasonic waveguide 80 may further include at least one
radial hole or aperture 66 extending there through, substantially
perpendicular to the longitudinal axis of the waveguide 80. The
aperture 66, which may be positioned at a node, is configured to
receive a connector pin 27 which connects the waveguide 80, to the
tubular actuating member 76, and the tubular outer sheath 72, a
rotation knob 29 together for conjoint rotation, including the end
effector 81, relative to instrument handle assembly 68.
[0071] In one embodiment of the present invention, the ultrasonic
waveguide 80 may have a plurality of grooves or notches (not shown)
formed in its outer circumference. The grooves may be located at
nodes of the waveguide 80 to act as alignment indicators for the
installation of a damping sheath 62 and stabilizing silicone rings
or compliant supports during manufacturing. A seal 67 may be
provided at the distal-most node, nearest the end-effector 81, to
abate passage of tissue, blood, and other material in the region
between the waveguide 80 and actuating member 76.
[0072] The blade 79 may be integral with the waveguide 80 and
formed as a single unit. In an alternate expression of the current
embodiment, blade 79 may be connected by a threaded connection, a
welded joint, or other coupling mechanisms. The distal end of the
blade 79 is disposed near an anti-node in order to tune the
acoustic assembly to a preferred resonant frequency f.sub.o when
the acoustic assembly is not loaded by tissue. When ultrasonic
transducer 50 is energized, the distal end of blade 79 is
configured to move longitudinally in the range of, for example,
approximately 10 to 500 microns peak-to-peak, and preferably in the
range of about 20 to about 200 microns at a predetermined
vibrational frequency f.sub.o of, for example, 55,500 Hz.
[0073] In accordance with the illustrated embodiment, blade 79 is
curved along with the associated clamp arm 56. This is illustrative
only, and blade 79 and a corresponding clamp arm 56 may be of any
shape as is known to the skilled artisan.
[0074] Ultrasonic transducer 50, and an ultrasonic waveguide 80
together provide an acoustic assembly of the present surgical
system 19, with the acoustic assembly providing ultrasonic energy
for surgical procedures when powered by generator 30. The acoustic
assembly of surgical instrument 100 generally includes a first
acoustic portion and a second acoustic portion. In the present
embodiment, the first acoustic portion comprises the ultrasonically
active portions of ultrasonic transducer 50, and the second
acoustic portion comprises the ultrasonically active portions of
transmission assembly 71. Further, in the present embodiment, the
distal end of the first acoustic portion is operatively coupled to
the proximal end of the second acoustic portion by, for example, a
threaded connection.
[0075] With particular reference to FIGS. 2, and 9-11, reciprocal
movement of actuating member 76 drives the clamp arm open and
closed. A force-limiting mechanism 91 is operatively connected to
actuating member 76 and comprises a tube collar cap 98 that secures
distal washer 97, distal wave spring 96, proximal washer 95 and
proximal wave spring 94 onto collar cap 93. Collar 93 includes
axially extending lugs 92 in engagement with suitable openings 75
in the proximal portion of tubular actuating member 76. A
circumferential groove 74 on the actuating member 76 receives on
O-ring 73 for engagement with the inside surface of outer sheath
72.
[0076] Rotation of the actuating member 76 together with tubular
outer sheath 72 and inner waveguide 80 is provided by a connector
pin 27 extending through these components and rotation knob 29.
Tubular actuating member 76 includes an elongated slot 31 through
which the connector pin 27 extends to accommodate reciprocal
movement of the actuating member 76 relative to the outer sheath 72
and inner waveguide 80.
[0077] The force limiting mechanism 91 provides a portion of the
clamp drive mechanism of the instrument 100, which affects pivotal
movement of the clamp arm 56 by reciprocation of actuating member
76. The clamp drive mechanism further includes a drive yoke 33
which is operatively connected with an operating trigger 34 of the
instrument, with the operating trigger 34 thus interconnected with
the reciprocable actuating member 76 via drive yoke 33 and force
limiting mechanism 91. Trigger 34 is rotatably connected to drive
yoke 33 via pins 35 and 36 and link 37 and rotatably connected to
drive yoke 33 and housing 68 via post 38.
[0078] Movement of trigger 34 toward handgrip 68 translates
actuating member 76 proximally, thereby pivoting clamp arm 56
toward blade 79. The trigger-like action provided by trigger 34 and
cooperating handgrip 68 facilitates convenient and efficient
manipulation and positioning of the instrument, and operation of
the clamping mechanism at the distal portion of the instrument
whereby tissue is efficiently urged against the blade 79. Movement
of trigger 34 away from handgrip 68 translates actuating member 76
distally, thereby pivoting clamp arm 56 away from blade 79.
[0079] With particular reference to FIGS. 1-4, therein is
illustrated one embodiment of clamp member 60 for use with the
present ultrasonic surgical instrument 100 and which is configured
for cooperative action with blade 79. The clamp member 60 in
combination with blade 79 is commonly referred to as the end
effector 81, and the clamp member 60 is also commonly referred to
as the jaw. The clamp member 60 includes a pivotally movable clamp
arm 56, which is connected to the distal end of outer sheath 72 and
actuation member 76, in combination with a tissue engaging pad or
clamp pad 58. In one expression of the embodiment, clamp pad 58 is
formed from TEFLON.RTM. trademark name of E. I. Du Pont de Nemours
and Company, a low coefficient of friction polymer material, or any
other suitable low-friction material. Clamp pad 58 mounts on the
clamp arm 56 for cooperation with blade 79, with pivotal movement
of the clamp arm 56 positioning the clamp pad in substantially
parallel relationship to, and in contact with, blade 79, thereby
defining a tissue treatment region. By this construction, tissue is
grasped between clamp pad 58 and blade 79. As illustrated, clamp
pad 58 may be provided with non-smooth surface, such as a saw
tooth-like configuration to enhance the gripping of tissue in
cooperation with the blade 79. The saw tooth-like configuration, or
teeth, provide traction against the movement of the blade. The
teeth also provide counter traction to the blade and clamping
movement. As would be appreciated by one skilled in the art, the
saw tooth-like configuration is just one example of many tissue
engaging surfaces to prevent movement of the tissue relative to the
movement of the blade 79. Other illustrative examples include
bumps, criss-cross patterns, tread patterns, a bead or sand blasted
surface, etc.
[0080] With particular reference to FIG. 3a, a first expression of
the current embodiment includes a clamp pad 58 having a proximal
portion 58b that is smoother than a distal portion 58a, such that
proximal portion 58b may be devoid of saw-tooth-like teeth or other
tissue engaging surfaces contemplated. Utilizing a smooth proximal
portion 58b on clamp pad 58 allows tissue in the proximal region to
move distally, following the vibratory motion of the blade, to the
more active region of the blade 79 to prevent tissue tagging. This
concept takes advantage of the inherent motion profile of blade 79.
Due to sinusoidal motion, the greatest displacement or amplitude of
motion is located at the most distal portion of blade 79, while the
proximal portion of the tissue treatment region is on the order of
50% of the distal tip amplitude. During operation, the tissue in
the proximal region of end effector (area of portion 58b) will
desiccate and thin, and the distal portion of end effector 81 will
transect tissue in that distal region, thereby allowing the
desiccated and thin tissue within the proximal region to slide
distally into the more active region of end effector 81 to complete
the tissue transaction.
[0081] In a second expression of the current embodiment, clamp pad
58 consists of one single pad having a smooth proximal end 58b and
a distal portion 58a that comprises a saw tooth-like configuration.
In a third expression of the current embodiment, clamp pad 58 may
consist of two separate components, distal portion 58a' that
comprises saw tooth-like teeth and proximal portion 58b' that is
smoother relative to distal portion 58a'. The advantage of two
separate components 58a' and 58b' is that each pad may be
constructed from different materials. For example, having a
two-piece tissue pad allows the use of a very lubricious material
at the distal end that is not particularly resistant to high
temperatures compared to a very high temperature material at the
proximal end that is not particularly lubricious because the
proximal end is an area of lower amplitude. Such a configuration
matches the tissue pad materials to the amplitude of the blade
79.
[0082] In a fourth expression of the current embodiment of the
present invention, clamp pad 58a' is formed from TEFLON.RTM. or any
other suitable low-friction material. Clamp pad 58b' is formed from
a base material and at least one filler material, which is a
different material from the base material. The surface of proximal
clamp pad 58b' may be smoother than distal clamp pad 58a', or
proximal clamp pad 58b' may also have a similar type saw-tooth
configuration.
[0083] Several benefits and advantages are obtained from one or
more of the expressions of the invention. Having a tissue pad with
a base material and at-least-one filler material allows the base
material and the at-least-one filler material to be chosen with a
different hardness, stiffness, lubricity, dynamic coefficient of
friction, heat transfer coefficient, abradability, heat deflection
temperature, glass transition temperature and/or melt temperature
to improve the wearability of the tissue pad, which is important
when high clamping forces are employed because tissue pads wear
faster at higher clamping forces than at lower clamping forces.
Applicants found, in one experiment, that a 15% graphite-filled
polytetrafluoroethylene tissue pad showed substantially the same
wear with a 7 pound clamping force as a 100%
polytetrafluoroethylene tissue pad showed with a 1.5 pound clamping
force. Having a flexible clamping arm and/or a flexible tissue pad
should also improve the wearability of the tissue pad due to the
ability of the flexible member to more evenly distribute the load
across the entire surface of the tissue pad. Further benefits and
expressions of this embodiment are disclosed in U.S. provisional
patent application Ser. No. 60/548,301, filed on Feb. 27, 2004 and
commonly assigned to the assignee of the present application, and
which the entire contents are incorporated by reference herein.
[0084] In a fifth expression of the current embodiment, a tissue
pad with a base material and at least two filler materials allows
the base material and the at-least-two filler materials to be
chosen with a different hardness, stiffness, lubricity, dynamic
coefficient of friction, heat transfer coefficient, abradability,
heat deflection temperature, and/or melt temperature to improve the
wearability of the tissue pad, which is important when high
clamping forces are employed because tissue pads wear faster at
higher clamping forces than at lower clamping forces. Applicants
found, in one experiment, that a 15% graphite-filled, 30%
PTFE-filled polyimide tissue pad showed substantially the same or
better wear with a 4.5 pound clamping force as a 100%
polytetrafluoroethylene tissue pad showed with a 1.5 pound clamping
force. The advantage of a 15% graphite-filled, 30% PTFE-filled
polyimide tissue pad is increased heat resistance, which improves
the overall wear resistance of the tissue pad. This
polyimide-composite clamp pad has a useful heat resistance up about
800.degree. F. to about 1200.degree. F., as compared to a useful
heat resistance up to about 660.degree. F. of a PTFE clamp pad.
Alternatively, Other materials are also useful for a portion of the
tissue pad (that is element 58b'), such as ceramics, metals,
glasses and graphite.
[0085] Referring to FIGS. 3a-e, one expression of clamp arm 56 has
different shaped slots for accepting two or more tissue pads. This
configuration prevents mis-loading of the tissue pads and assures
that the appropriate pad is loaded at the correct location within
clamp arm 56. For example clamp arm 56 may comprise a distal
T-shaped slot 53a for accepting a T-shaped flange 53b' of distal
clamp pad 58a' and a proximal wedged-shaped or dove tailed-shaped
slot 55a for accepting a wedge-shaped flange 55b' of proximal clamp
pad 58b'. Tab stop 51 engages the proximal end of proximal clamp
pad 58b' to secure the clamp pads onto clamp arm 56. As would be
appreciated by those skilled in the art, flanges 53b' and 55b' and
corresponding slots 53a and 55a may have alternate shapes and sizes
to secure the clamp pads to the clamp arm. The illustrated flange
configurations shown are exemplary only and accommodate the
particular clamp pad material of one embodiment, but the particular
size and shape of the flange may vary, including, but not limited
to, flanges of the same size and shape. For unitary tissue pads,
the flange may be of one configuration. Further, other tab stops
are possible and may include any of the multiple methods of
mechanically attaching the clamp pads to the clamp arm, such as
rivets, glue, press fit or any other fastening means well know to
the artisan.
[0086] In a second expression of the current embodiment, clamp pads
58a and 58b are cut on a bias so the interface between the two pads
creates an overlap to minimize gapping (FIGS. 4a, 4b). For example,
a 45 degree biased cut does allow some gapping to occur, but the
amount of gap seen by the tissue is minimized.
[0087] In a third expression of the current embodiment, clamp arm
56 increases in its height dimension from the distal end to the
proximal end (D.sub.1<D.sub.2). Preferably, D.sub.2 is from
about 105% to about 120% greater than D, and more preferably,
D.sub.2 is from about 108% to about 113% greater than D.sub.1, and
most preferably, D.sub.2 is about 110% greater than D.sub.1. Slot
153 accepts the flanges from one clamp pad 58 or two clamp pads 58a
and 58b. Tapered clamp arm 56 allows for the use of use flat pads
and increases the pressure in the proximal portion of end effector
81 as well as the interference with blade 79. When clamp arm 56
deflects at a greater rate than the blade 79, pressure still exists
at the tissue pad and blade interface and no gap is created.
Additionally, the increased pressure helps to offset the decreased
blade amplitude at the proximal end of blade 79 and provides a
relatively constant pressure between the clamp pad 58 and blade
79.
[0088] A first expression for a method for inserting clamp pads
includes a) inserting first and second clamp pads having a
first-shaped flange into a clamp arm 56 having a slot that accepts
the first-shaped flange; and b) engaging a pad stop to secure the
clamp pads within the clamp arm. In a second expression of this
method one clamp pad may be fabricated from a polymeric material
such as TEFLON, and the second clamp pad may be fabricated from a
base material and at least one filler material, which is a
different material from the base material and that clamp arm is
fabricated from metal, such as stainless steel, or titanium. The
tissue surfaces of the clamp pads may be smooth or have tissue
gripping features, such as a saw-tooth configuration.
[0089] A third expression for a method for inserting clamp pads
includes a) inserting a first clamp pad having a first-shaped
flange into a clamp arm having a slot that accepts the first-shaped
flange; b) inserting a second clamp pad having a second-shaped
flange into the clamp arm having a slot that accepts the
second-shaped flange; and c) engaging a pad stop to secure the
clamp pads within the clamp arm. In a fourth expression of this
method one clamp pad may be fabricated from a polymeric material
such as TEFLON, and the second clamp pad may be fabricated from a
base material and at least one filler material, which is a
different material from the base material and that clamp arm is
fabricated from metal, such as stainless steel, or titanium. The
tissue surfaces of the clamp pads may be smooth or have
tissue-gripping features, such as a saw-tooth configuration.
[0090] A first expression of a method for replacing clamp pads 58
would include the steps of: a) disengaging a pad stop; b) removing
a first clamp pad from the clamp arm; c) removing a second clamp
pad from the clamp arm; d) inserting third and fourth clamp pads
into the clamp arm; and e) engaging a pad stop to secure the third
and fourth clamp pads within the clamp arm. In a second expression
of this method one of the third and fourth clamp pads may be
fabricated from a polymeric material such as TEFLON, and the other
clamp pad may be fabricated from a base material and at least one
filler material, which is a different material from the base
material and that clamp arm is fabricated from metal, such as
stainless steel, or titanium. The tissue surfaces of the clamp pads
may be smooth or have tissue gripping features, such as a saw-tooth
configuration.
[0091] Referring now to FIG. 4, pivotal movement of the clamp
member 60 with respect to blade 79 is affected by the provision of
a pair of pivot points on the clamp arm 56 that interface with the
outer tube 72 and inner tube 76 respectively. The outer tube 72 is
grounded to handle 68 through rotation knob 29. Clamp arm 56 is
pivotally connected to outer tube 72 via corresponding through
holes 52a and 52b on clamp arm 56 and 52c and 52d on outer tube 72.
A securing pin or rivet 57 slides through holes 52a-d to secure
clamp arm 56 to outer tube 72. In one embodiment pin 57 is laser
welded to clamp arm 56 so that pin 57 is fixed to clamp arm 56 and
rotates relative to outer sheath 72.
[0092] Inner tube 76 translates along the longitudinal axis of
outer tube 72 and is grounded to the handle 68 through rotation
knob 29. Pivot studs 54a,b (54a not shown) on clamp arm 56 engage
pivot holes 54c,d (54d not shown) at the distal end of inner tube
76. The pivotal connection of clamp arm 56 to the inner and outer
tubes 76, 72 provide more robustness to the end effector 81 and
minimize failure modes due to excessive axial or torsional abuse
loads. Further, the embodiment increases the effectiveness of the
end effector 81 to provide clamp forces in excess of 1.5 lbs.
Reciprocal movement of the actuating member 76, relative to the
outer sheath 72 and the waveguide 80, thereby affects pivotal
movement of the clamp arm 56 relative to the end-blade 79.
[0093] FIG. 4c illustrates a force diagram and the relationship
between the actuation force F.sub.A (provided by actuation member
76) and transection force F.sub.T (measured at the midpoint of the
optimal tissue treatment area). F.sub.T=F.sub.A(X.sub.2/X.sub.1)
Equation [1]
[0094] Where F.sub.A equals the spring preload of proximal spring
94 (less frictional losses), which, in one embodiment, is about
12.5 pounds, and F.sub.T equals about 4.5 pounds as shown in FIG.
16c. FIG. 16c provides a graphical illustration of F.sub.T and
F.sub.A as a function of trigger 34 movement as well as input
forces at trigger 34.
[0095] F.sub.T is measured in the region of the clamp arm/blade
interface where optimal tissue treatment occurs as defined by
tissue marks 61a and 61b. Tissue marks 61a, b are etched or raised
on clamp arm 56 to provide a visible mark to the surgeon so the
surgeon has a clear indication of the optimal tissue treatment
area. Tissue marks 61a,b are about 7 mm apart in distance, and more
preferably 5 mm apart in distance.
[0096] Rotation of the transmission assembly 71 of ultrasonic
surgical instrument 100 may be affected together with relative
rotational movement of ultrasonic transducer 50 with respect to
instrument handle assembly 68. In order to join the transmission
assembly 71 to the ultrasonic transducer 50 in
ultrasonic-transmitting relationship, the proximal portion of the
outer sheath 72 may be provided with a pair of wrench flats 46. The
wrench flats 46 allow torque to be applied by a suitable torque
wrench or the like to thereby permit the waveguide 80 to be joined
to the ultrasonic transducer 50. The ultrasonic transducer 50, as
well as the transmission assembly 71, is thus rotatable, as a unit,
by suitable manipulation of rotation knob 29, relative to handle
assembly 68 of the instrument. The interior of handle assembly 68
is dimensioned to accommodate such relative rotation of the
ultrasonic transducer 50. A spring 28 is loaded against rotation
knob 29 and an inner housing surface 65. Spring 28 provides a
compression or force against rotation knob 29 to inhibit
inadvertent rotation of end effector 81.
[0097] Referring now to FIGS. 2, 5, 6 and 16, force limiting
mechanism 91 provides a first and second compression spring, distal
spring 96 and proximal spring 94. Distal spring 96 is operationally
coupled to yoke 33, which in turn is driven by trigger 34. Proximal
spring 94 is in operational relationship with distal spring 96.
Distal spring 96 generates the end effector load and proximal
spring 94 maintains the consistency of the end effector load. As a
result, the end effector load is more tightly controlled and
component abuse load conditions are reduced. Washers 97 and 95 are
a safe guard against distal spring 96 being fully compressed (FIG.
5), thereby preventing the spring material to yield and render
spring 96 useless in subsequent clamp arm closures. As would be
appreciated by one skilled in the art, the application of a dual
spring force limiting system has applicability in other
energy-based surgical devices (such as RF, microwave and laser)
that encounter clamping forces, as well as mechanical devices, such
as, clip appliers, graspers and staplers.
[0098] In one expression of the current embodiment, distal spring
96 has a spring constant greater than 100 pounds per inch and
preferably greater than 125 pounds per inch and most preferably
about 135 pounds per inch. It is not required that distal spring 96
be preloaded, but may be preloaded at less than 10 pounds, and
preferably less than 5 pounds, and most preferably at about 1
pound. Proximal spring 94 has a spring constant greater than 25
pounds per inch and preferably greater than 50 pounds per inch and
most preferably about 70 pounds per inch. Proximal spring 94 is
preloaded to a force necessary to achieve the desired transection
force as noted in Equation 1, above, and is a function of the
mechanical advantage of the clamp arm 56 coupling means and
frictional losses in the device. In a second expression of the
current embodiment, proximal spring 94 is preloaded at about 12.5
pounds.
[0099] Referring now to FIG. 16a, curve 82 illustrates actuation
member 76 force and curve 83 represents trigger 34 force as a
function of the angular rotation of trigger 34 (on the x-axis,
-18.0 is the clamp arm 56 fully open and 0.0 is the clamp arm fully
closed and against blade 79) under no tissue or minimal tissue load
operation. Point 82a represents the point at which yoke 33 begins
to deflect or compress distal spring 96 and the actuation member 76
force increases as trigger 34 is depressed further until the force
reaches the preload value of proximal spring 94 at inflection point
82b, and the slope of the force curve decreases.
[0100] In FIG. 16b, curve 84 illustrates actuation member 76 force
and curve 85 represents trigger 34 force as a function of the
angular rotation of trigger 34 under abusive tissue load operation,
whereby tissue completely fills the end effector in the open
position. Point 84a represents the point at which yoke 33 begins to
deflect or compress distal spring 96 and the actuation member 76
force increases as trigger 34 is depressed until the force reaches
the preload value of proximal spring 94 at inflection point 84b, at
which point the slope of the force curve decreases.
[0101] Referring now to FIGS. 2 and 5, surgical instrument 100
further provides for a means for indicating to the surgeon that the
trigger has reached full travel and the clamp arm 56 is applying
the correct coaptation force to the tissue. This is useful during
protracted surgical operations or tissue transection activities
when the surgeon's grip may relax, just a bit, without the
surgeon's knowledge, and the pressure delivered to the tissue from
the clamp arm 56 may be unknowingly decreased.
[0102] In one expression of the current embodiment, a detent spring
110 is supported within a detent support 112 located within housing
portion 69. A detent tab 114 on trigger 34 engages and snaps back
detent spring 110 when trigger 34 is fully closed or actuation
member 76 has reached it most proximal travel. Detent spring 110 is
generally planar and made of a flexible plastic that adequately
deflects when it engages tab 114 thereby providing an audible
and/or tactile signal to the surgeon that there is full end
effector 81 closure. Advantageously, tab 114 strikes and deflects
detent spring 110 when trigger 34 is rotated from the full closure
position and in the opposite direction thereby providing an audible
and/or tactile signal to the surgeon that full closure of end
effector 81 no longer exists. As would be appreciated by the
skilled artisan, the indicating means may be either tactile,
audible or visual or a combination. Various types of indicators may
be used including dome switches, solid stops, cantilever springs or
any number of mechanical or electrical switches known to those
skilled in the art. Further various means may be used to provide
feedback to the surgeon, including, but not limited to, lights,
buzzers, and vibratory elements.
[0103] Referring now to FIGS. 1, 2 and 6-8 housing 68 includes a
proximal end, a distal end, and a cavity 59 extending
longitudinally therein. Cavity 59 is configured to accept a switch
assembly 300 and the transducer assembly 50, which interfaces with
housing 68 via switch assembly 300.
[0104] Transducer 50 includes a first conductive ring 400 and a
second conductive ring 410 which are securely disposed within the
transducer body 50. In one expression of the current embodiment,
first conductive ring 400 comprises a ring member, which is
disposed between the transducer 50 and the horn 130. Preferably the
first conductive ring 400 is formed adjacent to or as part of the
flange member 160 within the cavity 162 and is electrically
isolated from other electrical components. The first conductive
ring 400 is anchored to and extends upwardly from a non-conductive
platform or the like (not shown) which is formed within the
transducer body 50. The first conductive ring 400 is electrically
connected to the cable 22 (FIG. 1) by means of one or more
electrical wires (not shown), which extend along the length of the
transducer body 50 to the first conductive ring 400.
[0105] The second conductive ring 410 of the transducer 50
similarly comprises a ring member that is disposed between the
transducer body 150 and the horn 130. The second conductive ring
410 is disposed between the first conductive ring 400 and the horn
130 and therefore the first and second conductive rings 400, 410
are concentric members. The second conductive ring 410 is likewise
electrically isolated from the first conductive ring 400 and other
electrical components contained within the transducer 50. Similar
to the first conductive ring 400, the second conductive ring 410
preferably is anchored to and extends upwardly from the
non-conductive platform. It will be understood that the first and
second conductive rings 400, 410 are sufficiently spaced from one
another so that they are electrically isolated from each other.
This may be accomplished by using one or more spacers 413 disposed
between the first and second conductive rings 400, 410 or between
the rings 400, 410 and other members within the transducer 50. The
second conductive ring 410 is also electrically connected to the
cable 22 (FIG. 1) by means of one more electrical wires (not
shown), which extend along the length of the transducer 50 to the
second conductive ring 410. The second conductive ring 410 is thus
provided to partially define a second electrical pathway from the
cable 22 to the switch mechanism 300. A suitable ultrasonic
transducer 50 is Model No. HP054, sold by Ethicon Endo-Surgery,
Inc. of Cincinnati, Ohio.
[0106] In one expression of the current embodiment, the distal end
of transducer 50 threadedly attaches to the proximal end of
transmission rod 80. The distal end of transducer 50 also
interfaces with switch assembly 300 to provide the surgeon with
finger-activated controls on surgical instrument 100.
[0107] Switch assembly 300 comprises a pushbutton assembly 310, a
flex circuit assembly 330, a switch housing 350, a first spring
slip ring conductor 360 and a second spring slip ring conductor
370. Switch housing 350 is generally cylindrical and is supported
within handle assembly 68 by way of corresponding supporting mounts
on switch assembly 350 and housing portions 69 and 70. Housing 350
defines a first cavity 353, a mounting boss 352 and a second cavity
351. Cavity 353 is sized to accept the proximal end of transducer
50, whereby horn 130 passes through cavity 351 to interface with
transmission rod 80. Mounting boss 352 accepts slip ring conductors
360 and 370, which in turn electrically engage ring contacts 400
and 410, respectively. An alignment pin 354 and snap-fit pin 355
align with corresponding apertures of the flex circuit assembly 330
and pushbutton assembly 310 to secure all components together as
discussed below.
[0108] With particular reference now to FIG. 8a, slip ring
conductors 360 and 370 are generally open-ended O-shaped springs
that slip onto mounting boss 352. Each spring slip-ring comprises
two pressure point contacts (361a-b and 371a-b) that contact the
respective ring conductor 400 and 410 of transducer 50. The spring
tension of the slip rings 360 and 370 cause positive contact
between contacts 361a-b, 371a-b and conductors 400 and 410. It is
evident that the slip-ring construction allows electrical contact
to be made even as transducer 50 may be rotated by the surgeon
during use of the instrument. Posts 364 and 374 of the respective
slip rings electrically connect to the respective conductor within
flex circuit 330 to complete the electrical circuit as shown in
FIG. 8c.
[0109] A flex circuit 330 provides for the electro-mechanical
interface between pushbuttons 311a, b, 312a, b and the generator 30
via transducer 50. Flex circuit comprises four dome switches 332a,b
and 334a, b that are mechanically actuated by depressing
pushbuttons 311a, b or 312a, b, respectively of corresponding
pushbutton assembly 310. Dome switches 332 and 334 are electrical
contact switches, that when depressed provide an electrical signal
to generator 30 as shown by the electrical wiring schematic of FIG.
8c. Flex circuit 330 also comprises two diodes within a diode
package 336, also illustrated in FIG. 8c. Flex circuit 330 provides
conductors, 335 and 337 as is known to those in the art, that
connect to slip ring conductors 360 and 370 via electrical tabs 364
and 374, respectively, which in turn provide electrical contact to
ring conductors 400 and 410, which in turn are connected to
conductors in cable 22 that connect to generator 30. Tabs 364 and
374 are soldered to conductors 335 and 337.
[0110] Flex circuit 330 generally wraps around switch housing 350
so that dome switches 334a, b and 332a, b interface with the
corresponding backing surfaces 356a, b and 358a, b on switch
housing 350. Backing surfaces provide a firm support for the dome
switches during operation, discussed below. Dome switches 334a, b
and 332a, b may be fixedly attached to backing surfaces 356a, b and
358a, b by any convenient method, such as, an adhesive. Flex
circuit is secured to switch housing 350 via alignment pin 354 and
snap-fit pin 355 on switch assembly 350 and corresponding alignment
hole 338 and snap-fit hole 339 on flex circuit 330.
[0111] Layered on top of flex circuit is pushbutton assembly 310,
which has a corresponding saddle-shape as flex circuit 330, and
generally wraps around switch housing 350. Pushbutton assembly 310
comprises four pushbuttons, distal pushbuttons 312a, b and proximal
pushbuttons 311a, b which have corresponding pressure studs 315a, b
and 314a, b. The pushbuttons are connected to cantilever elements
313a, b and 316a, b, which provide a spring-back action after the
pushbuttons are depressed. As is readily apparent, by depressing
pushbuttons 311 and 312 the corresponding pressure studs 314 and
315 depress against corresponding dome switches 334 and 332 to
activate the circuit illustrated in FIG. 8c. Switches 312a and b
are in parallel so that a surgeon may operate the pushbuttons using
either a left hand or a right hand. Likewise, switches 311a and b
are in parallel so that a surgeon may operate the pushbuttons using
either a left hand or a right hand. When the surgeon depresses
either switch 312a or 312b, the generator will respond with a
certain energy level, such as a maximum ("max") power setting; when
the surgeon depresses either switch 311a or 311b, the generator
will respond with a certain energy level, such as a minimum ("min")
power setting, which conforms to accepted industry practice for
pushbutton location and the corresponding power setting.
[0112] Alternatively, the pushbuttons may be molded into the switch
housing 350 or into the handle assembly 68 to reduce the number of
components and increase the reliability of the overall device. The
pushbuttons may be attached through small cantilever sections,
which allow for sturdy attachment of the pushbutton to the other
components, while at the same time allowing for a low force to
activate the pushbuttons.
[0113] Referring now to FIGS. 12-15, one expression of the current
embodiment allows switches 311a, b and 312a, b configured in such a
way to provide an ergonomically pleasing grip and operation for the
surgeon. Switches may be placed in the range of the natural swing
of the surgeon's thumb, whether gripping surgical instrument 100
right-handed or left handed. In a second expression of the current
embodiment, the switches are placed on housing 68 to prevent
inadvertent button activation on the side of the instrument
opposite the thumb while the surgeon depresses trigger 34 or
rotates rotation knob 29. In a third expression of the current
embodiment a series of partitions, such as ridges and/or
depressions or "peaks and valleys" that are integrated onto the
housing 68. In one example the housing defines a first surface and
the series of partitions define at least one second surface such
that the second surface is higher than the housing surface. The
partition may also define a third surface that is lower than the
housing surface. As can be seen in FIGS. 1, 2 switches 312a, b are
surrounded by an upper ridge 320 and a lower ridge 324. Ridges 320
and 324 may be discrete physical features, both separated from each
other, or ridges 320 and 324 may be continuous in nature without
departing from the scope of the invention. Further, the ridges 320
and 324 may continue across the entire upper portion of housing 68,
as shown in FIGS. 12-15, or ridges 320 and 324 may be more discrete
as shown in FIGS. 1 and 2. This construction and situation of
switches 312a, b prevent the risk of inadvertent button activation
even if a finger crosses over the button due to the fact that the
ridges cause the finger to pass above the plane of the button. The
ridges also provide tactile feedback to the surgeon as to the
location of the pushbuttons and whether the button represents min
or max power activation. As is readily evident, switches 312a, b
are surrounded by ridges 320 and 324 and pushbuttons 311a,b are
situated above and proximal of ridge 320. Such tactile feedback is
essential to the surgeon, so the surgeon may continuously assess
the surgical site, but confidently understand which pushbuttons are
being activated. In a further expression of the current embodiment,
switch 312a, b are nestled within a depression 322 and further
surrounded by ridges 320 and 324.
[0114] Referring to FIG. 12, a surgeon's left hand is accessing
instrument 100. The fore finger and middle finger are poised to
activate trigger 34, and the ring finger and pinkie grasp hand grip
39. The thumb is conveniently positioned to sweep upward to
activate pushbutton 312a or 311a. Ridges 320 and 324 extend across
the upper portion of housing 69.
[0115] In FIG. 13, the opposite side of instrument 100 shown in
FIG. 12 is illustrated showing pushbuttons 311b and 312b. Here the
surgeon's forefinger is accessing rotation knob 29 to rotate end
effector 81. As can be seen, pushbutton 312b is subject to
inadvertent activation by the forefinger. However, ridge 324 causes
the forefinger to elevate above the plane of pushbutton 312b
thereby reducing the risk of inadvertent activation.
[0116] In FIG. 14, the surgeon has depressed trigger 34 to close
clamp arm 56 against blade 79, and the left thumb has easily
accessed pushbutton 312b to activate max power.
[0117] In FIG. 15, the surgeon has depressed trigger 34 to close
clamp arm 56 against blade 79, and the left thumb has easily
accessed pushbutton 311b to activate min power.
[0118] Referring to FIG. 17, an expression of surgical instrument
100 is shown graphically illustrating a surgeon's finger placement
on instrument 100. Instrumental in the activation of the instrument
100 is the placement of the forefinger 382 and middle finger 384 on
trigger 34. (Using the forefinger and middle finger to activate
trigger 34 is exemplary only. Surgeons with smaller hands may opt
to activate trigger 34 with the middle finger and ring finger,
thereby making the forefinger available to rotate knob 29 or even
use the ring finger and pinkie to active trigger 34.) Trigger 34
comprises a base element 45, which comprises the detent tab 114 and
linkage with yoke 33, discussed below. Attached to base element 45
is a generally T-shaped finger interface 43, which in conjunction
with base element 45 define two generally U-shaped openings, a
forefinger groove 42 and a middle finger groove 44. The most distal
surface portion of T-shaped finger interface 43 defines an
actuating surface 41 that also accepts placement of fingers 382 and
384. Grooves 42 and 44 are sized to accept different sized fingers,
a common variable as is evident depending upon the sex and size of
the surgeon. In a first expression of the current embodiment, the
size of grooves 42 and 44 are based on anthropic data for 5th
percentile females through to 95th percentile males for finger
size. In a second expression of the current embodiment, grooves 42
and 44 are tapered, whereby the dimension of each groove opening is
larger than the dimension of base of each groove 42 and 44. This
configuration advantageously allows fingers of varying size to
nestle snuggly within each groove and minimize the clearance
between the finger and walls of the grooves.
[0119] Referring now also to FIGS. 10 and 11, the clamp arm 56 is
fully open relative to the blade 79 when trigger 34 is in its most
distal position (FIG. 10). Fingers 382 and 384 may be placed within
respective grooves 42 and 44 or alternatively on surface 41 to
actuate trigger 34 through its arcuate travel designated by arrow
47. When trigger reaches its full proximal travel (when detent tab
114 engages detent spring 110), the clamp arm 56 is in its fully
closed position relative to the blade 79 (FIG. 11). In order to
reverse the trigger along its travel 47, fingers 382 and 384 engage
grooves 42 and 44 and push trigger 34 distally to open the end
effector. The clamp arm 56 is not biased open so the surgeon cannot
control the opening of clamp arm 56 via surface 41.
[0120] Referring now to FIG. 18, elements having similar reference
numerals as shown in FIG. 2 have the similar function as already
discussed. Particular attention is directed to an alternate handle
assembly 168 for actuating the end effector 81. The handle assembly
168 includes two pivoting handle portions 420 and 422 coupled to a
right shroud 169 and a left shroud 170.
[0121] The right shroud 169 is adapted to snap fit on the left
shroud 170 via a plurality of inwardly facing prongs formed on the
left shroud 170 to form housing 171. When the left shroud 170 is
attached to the right shroud 169, a cavity is formed therebetween
to accommodate various components that form the handle assembly 168
as further discussed below. Apertures 172 and 174 are also formed
to accommodate thumb ring or handle portion 420 and finger ring or
handle portion 422, which are located exterior of the left and
right shrouds to the actuating linkage contained within the left
and right shrouds. Aperture 173 is also formed at the proximal end
of shrouds to accommodate transducer 50 (See FIG. 8b).
[0122] Handle assembly 168 includes a U-shaped yoke 424 slidably
attachable within housings 169 and 170 via slots 421a and 421b and
pins 423a and 423b, respectively. The distal end of handle 420 at
hole 402 attaches to right shroud 169 and yoke via pin 423a, and
the proximal end of handle 420 attaches to yoke 424 via link 428
attached to hole 404 via pin 426 and hole 410 via pin 430. The
distal end of handle 422 at hole 406 attaches to right shroud 169
and yoke via pin 423b, and the proximal end of handle 422 attaches
to yoke 424 via link 432 attached to hole 408 via pin 434 and hole
412 via pin 430. In practice as the handles 420 and 422 are moved
away from housing 171 (for example, the surgeon's thumb cooperates
with handle 420, and the surgeon's forefinger and middle finger
cooperate with handle 422), end effector 81 moves away from blade
79 to form an open jaw (the open position), and as handles 420 and
422 are moved toward housing 171, end effector 81 rotates toward
blade 79 to capture tissue (the closed position).
[0123] In one expression of the current embodiment, a detent spring
482 is supported within housing portion 171. A detent cam 480
rotates on yoke 168 and engages and snaps back detent spring 482
when handles 420 and 422 are in the fully closed position. Detent
spring 482 is generally made of a flexible plastic that adequately
deflects when it engages cam 480 thereby providing an audible
signal to the surgeon that there is full end effector 81 closure.
Advantageously, 480 strikes and deflects detent spring 482 when
handles 420 and 422 are rotated from the full closure position and
in the opposite direction thereby providing an audible signal to
the surgeon that full closure of end effector 81 no longer
exists.
[0124] Referring also now to FIG. 24, a second expression of the
current embodiment is shown having an actuator post 433 attaches to
handle 422 and engages a dome switch 435 covered by silicon rubber
located on housing assembly 171. When handle 422 is fully closed,
post 433 presses against the silicone which in turn transfers the
force to the dome switch 435, allowing the switch to provide an
audible and tactile feedback to the surgeon. In one embodiment post
433 is a cylinder having a diameter of 0.170 inches with a 0.070
inch slot in the middle. A preferred durometer for the silicon
rubber material is 20 Shore A.
[0125] Referring also now to FIG. 23, also enclosed within housing
171 are connector 450, slip rings 452, 454, flex circuit 456 and
rocker switch 462. Rocker switch 462 rotatably attaches to right
shroud 169 via aperture 469 and switches 462 and 464 are positioned
exterior housing 171 for access by the surgeonu. Switches 462 and
464 are mechanically connected via a rocker arm 466 comprising a
pivot post 468 which interfaces with aperture 469. In this
configuration, switches 462 and 464 cannot be simultaneously
depressed, which, if were the case, would provide an error message
from generator 30. A flex circuit 456 provides for the
electro-mechanical interface between switches 464 and 466 and the
generator 30 via the transducer 50 (see FIG. 8b). Referring to FIG.
21, flex circuit 456 includes, at the distal end, two dome switches
500 and 502 that are mechanically actuated by depressing
corresponding switches 464 and 466, respectively. Dome switches 500
and 502 are electrical contact switches, that when depressed
provide an electrical signal to generator 30 as shown by the
electrical wiring schematic of FIG. 22. Flex circuit 456 also
comprises two diodes within a diode package 504, also illustrated
in FIG. 22. Flex circuit 456 provides conductors, as is known to
those in the art, that connect to slip ring conductors 452 and 454
via connector 450, which in turn provide electrical contact to ring
conductors 400 and 410 (FIG. 8b), which in turn are connected to
conductors in cable 32 that connect to generator 30.
[0126] With particular reference now to FIGS. 19 and 20a-b, slip
ring conductors 452 and 454 are generally open-ended O-shaped
springs that slip onto mounting surfaces 453 and 455 of connector
450, respectively. Each spring slip-ring comprises two pressure
point contacts (510a-b and 522a-b) that contact the respective ring
conductor 400 and 410 of handpiece 50. The spring tension of the
slip rings 452 and 454 cause positive contact between contacts
510a-b, 522a-b and conductors 400 and 410. It is evident that the
slip-ring construction allows electrical contact to be made even as
hand piece 50 may be rotated by the surgeon during use of the
instrument. Posts 512 and 524 of the respective slip rings
electrically connect to the respective conductor within flex
circuit 456 to complete the electrical circuit as shown in FIG.
22.
[0127] Referring again to FIG. 18, rotation coupler 130 rotatably
engages the distal end of right and left shrouds 169 and 170.
Rotation knob 129 couples to rotational coupler 130, whereby two
spring tabs 175 and 175a (not shown) provide an outward tension or
force against the inner surface of rotation knob 129 to inhibit
inadvertent rotation of end effector 81.
[0128] In an alternate expression of the invention, handles 420 and
422 have a soft-touch molded thermo plastic elastomer liner 550 on
the inner surface of handles 420 and 422. Plastic liner 550
provides comfort to the surgeon and prevents finger and hand
fatigue. Plastic liner 550 also provides an enhance gripping
surface between the handles and the surgeon's thumb and fingers as
opposed to the smooth plastic surface interface of the prior art.
This is particularly advantageous for accepting multiple digit
sizes of male and female surgeons and still providing a comfortable
and positive gripping surface. Plastic liner 550 may be smooth or
have contours molded onto the surface of liner 550, such as ribs,
as illustrated in FIGS. 23 and 24. Other contours may be bumps, and
peaks and valleys. Various other shapes and interfaces are within
the scope of this invention as would be obvious to one skilled in
the art. Plastic liner 550 is also useful on the interface between
the surgeon's finger and trigger 34 (FIG. 12).
[0129] In one expression of the current embodiment, the soft-touch
liner 550 has a durometer (hardness) rating from about 35 Shore A
to about 75 Shore A, and more particularly from about 50 Shore A to
about 60 Shore A. Such appropriate materials are available from LNP
of Exton, Pa. (stock no. 8211-55 B100GYO-826-3) and Advanced
Elastomer Systems of Akron, Ohio (stock no. 8211-55B100).
[0130] The soft-touch material may also be useful to help the
surgeon identify a particular feature of the instrument while the
surgeon is focused on the operation at hand. For example, a "soft
touch" having one contour interface may be placed on the "max"
button, and a "soft touch" having a second contour interface may be
place on the "min" button so the surgeon may easily recognize the
presence of either button without having to lose focus of the
surgical site. "Soft touch" may also be implemented on knobs 29 and
129 with contours to identify various rotation positions of end
effector 81.
[0131] While the present invention has been illustrated by
description of several embodiments, it is not the intention of the
applicant to restrict or limit the spirit and scope of the appended
claims to such detail. Numerous variations, changes, and
substitutions will occur to those skilled in the art without
departing from the scope of the invention. Moreover, the structure
of each element associated with the present invention can be
alternatively described as a means for providing the function
performed by the element. Accordingly, it is intended that the
invention be limited only by the spirit and scope of the appended
claims.
* * * * *