Source: http://www.docstoc.com/docs/76822788/Electroactive-Polymer-based-Articulation-Mechanism-For-Grasper---Patent-7862579
Timestamp: 2014-03-09 09:12:26
Document Index: 548381895

Matched Legal Cases: ['Application No. 200610146378', 'Application No. 200610144755', 'Application No. 05', 'Application No. 05254703', 'Application No. 06255053', 'Application No. 06255057', 'Application No. 06255058', 'Application No. 06255062', 'Application No. 06255064', 'Application No. 06255065', 'Application No. 60']

Electroactive Polymer-based Articulation Mechanism For Grasper - Patent 7862579
United States Patent: 7862579
7,862,579
grasping device. In one exemplary embodiment, a grasping device is
provided having a shaft with an end effector having opposed jaws coupled
to the shaft. An electrically expandable and contractible actuator, such
as an electroactive polymer actuator, can be used to actuate the end
effector to open and close the opposed jaws to grasp tissue or other
objects. In another embodiment, an electroactive polymer actuator can be
used to pivotally or angularly adjust a position of the end effector
relative to the shaft by delivering energy to the electroactive polymer
11/162,991
11082495Mar., 20057506790
606/205  ; 227/175.1; 227/176.1; 227/180.1; 227/19
606/205,206,207 227/175.1,176.1,180.1,19
5592668
Peirine et al.
6699245
7513408
0832605
DE19537299
DE19643073
DE19647354
D1993372
WO-0043828
WO-0078222
WO-0156455
WO-0162158
WO-0162163
WO-0228268
03088845
03090630
03094746
WO-03094743
WO-2004014238
WO-2004050971
2004086987
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No. 11/082,495 filed on Mar. 17, 2005 now U.S. Pat. No. 7,506,790, and
entitled &quot;Surgical Instrument Incorporating an Electrically Actuated
Articulation Mechanism,&quot; which claims priority to U.S. Provisional
Application No. 60/591,694 filed on Jul. 28, 2004 and entitled &quot;Surgical
Instrument Incorporating an Electrically Actuated Articulation
Mechanism.&quot; These applications are hereby incorporated by reference in
1.  A grasping device, comprising: an elongate shaft defining a longitudinal axis;  an end effector movably coupled to the shaft by an articulation joint, the end effector
having opposed first and second jaws formed on a distal end thereof and movable between an open and closed position;  and an electroactive polymer actuator disposed within the elongate shaft and expandable in a direction orthogonal to the longitudinal
axis of the elongate shaft when energy is delivered to the electroactive polymer actuator such that the electroactive polymer actuator is configured to move the end effector about the articulation joint relative to the shaft.
2.  The device of claim 1, wherein the elongate shaft includes a slide bar extending therethrough and having a distal end coupled to the articulation joint, the electroactive polymer actuator being configured to move the slide bar in a direction
orthogonal to the longitudinal axis of the elongate shaft to effect movement of the end effector.
3.  The device of claim 2, wherein the electroactive polymer actuator comprises first and second electroactive polymer actuators disposed on opposed sides of the slide bar.
4.  The device of claim 2, wherein the slide bar includes gears formed on a distal end thereof and adapted to engage corresponding gears formed in the articulation joint.
5.  The device of claim 1, wherein the articulation joint comprises a pivot joint, and the electroactive polymer actuator comprises a first electroactive polymer actuator extending between a first side of the end effector and a first side of the
elongate shaft, and a second electroactive polymer actuator extending between a second opposed side of the end effector and a second opposed side of the elongate shaft.
6.  The device of claim 1, wherein the articulation joint comprises a flexible portion formed between the elongate shaft and the end effector.
7.  The device of claim 6, wherein the electroactive polymer actuator comprises a plurality of electroactive polymer actuators coupled to the flexible portion at distinct locations, each of the plurality of electroactive polymer actuators being
configured to change orientations when energy is selectively delivered thereto to flex the flexible portion.
8.  The device of claim 1, further comprising an electroactive polymer actuator coupled to the opposed jaws and effective to move the opposed jaws between an open and closed position when energy is delivered to the electroactive polymer
Known surgical graspers include an end effector that can be actuated to grasp tissue or other devices or objects.  The end effector includes a pair of cooperating jaw members that, if the instrument is intended for endoscopic or laparoscopic
applications, are capable of passing through a cannula passageway.  The jaws can then be opened and closed to grasp and manipulate tissue.  Some devices have end effectors that can be pivotally coupled to the shaft or a shaft that can be flexible
relative to the end effector to allow the end effector to be angularly oriented to facilitate grasping of tissue.  One drawback to such articulating devices, however, is that a mechanical linkage is used to transfer a force from a handle of the device to
the end effector to activate the end effector.  The mechanical linkage can interfere with the pivoted or curved orientation of the shaft, potentially causing it to straighten.
The present invention generally provides methods and devices for articulating and/or actuating a laparoscopic or endoscopic grasping device.  In one exemplary embodiment, the grasping device can include a shaft with an end effector formed on a
distal end thereof and having opposed first and second jaws for grasping tissue or other objects.  The end effector can include one or more electroactive polymer actuators coupled thereto and effective to move the jaws between an open and closed
position.  The device can also include a handle formed on a proximal end of the shaft with a control mechanism that is adapted to selectively deliver energy to the electroactive polymer actuator(s).
In one embodiment, each jaw can include a proximal end and a distal end, and the first and second jaws can be coupled to one another at a pivot point formed between the proximal and distal ends.  One or more electroactive polymers can be coupled
to the proximal end of each jaw to open or close the jaws.  In one embodiment, a first electroactive polymer actuator can extend between the proximal end of the first jaw and the shaft, and a second electroactive polymer actuator can extend between the
proximal end of the second jaw and the shaft.  The first and second electroactive polymer actuators can be adapted to axially contract when energy is delivered thereto to pull the proximal ends of the first and second jaws toward the shaft, thereby
moving the first and second jaws to an open or closed position, depending upon the configuration of the jaws.  In another embodiment, an electroactive polymer actuator can extend between a proximal end of each of the first and second jaws, and it can be
effective to move the first and second jaws to an open or closed position when energy is delivered to the electroactive polymer actuator(s).  The device can also include a biasing element, such as a spring, that is adapted to bias the jaws to an open or
A method for grasping objects is also provided and can include inserting a grasping device into a lumen of a body, and delivering energy to at least one electroactive polymer actuator coupled to at least one of the first and second jaws to engage
an object between the jaws.  In one exemplary embodiment, the jaws can be biased to an open position and the electroactive polymer actuator can close the jaws when energy is delivered thereto.  In another embodiment, the jaws can be biased to a closed
position, and the electroactive polymer actuator can open the jaws when energy is delivered thereto.
In another embodiment, a grasping device is provided having a shaft, and an end effector movably coupled to the shaft by an articulation joint.  The end effector can have opposed first and second jaws formed on a distal end thereof and movable
between an open and closed position.  The device can also include an electroactive polymer actuator coupled to the articulation joint and adapted to move the end effector about the articulation joint relative to the shaft when energy is delivered to the
electroactive polymer actuator.
While various techniques can be used to move the articulation joint using the end effector, in one embodiment the elongate shaft can include a slide bar extending therethrough and having a distal end coupled to the articulation joint.  The
electroactive polymer actuator can be configured to move the slide bar laterally to effect movement of the end effector.  For example, the electroactive polymer actuator can include first and second electroactive polymer actuators disposed on opposed
sides of the slide bar.  The slide bar can include gears formed on a distal end thereof and adapted to engage corresponding gears formed in the articulation joint.  In another embodiment, the articulation joint can be in the form of a pivot joint, and
the electroactive polymer actuator can include a first electroactive polymer actuator extending between a first side of the end effector and a first side of the elongate shaft, and a second electroactive polymer actuator extending between a second
opposed side of the end effector and a second opposed side of the elongate shaft.  In yet another embodiment, the articulation joint can be in the form of a flexible portion formed between the elongate shaft and the end effector.  The electroactive
polymer actuator can include a plurality of electroactive polymer actuators coupled to the flexible portion at distinct locations, each of the plurality of electroactive polymer actuators being configured to change orientations when energy is selectively
delivered thereto to flex the flexible portion.
Methods for grasping tissue are also provided and in one exemplary embodiment the method can include inserting an elongate shaft of a grasping device into a body lumen to position opposed jaws of an end effector movably coupled to a distal end of
the elongate shaft adjacent to tissue to be grasped, delivering energy to an electroactive polymer actuator to angularly position the end effector relative to the elongate shaft and thereby position the tissue to be grasped between the opposed jaws, and
closing the opposed jaws to grasp the tissue.  Delivering energy to the electroactive polymer actuator can cause the electroactive polymer actuator to radially expand to move a slide bar, extending through the elongate shaft and coupled to an
articulation joint formed between the elongate shaft and the end effector, laterally and thereby effect pivotal movement of the end effector.  Alternatively, delivering energy to the electroactive polymer actuator can cause the electroactive polymer
actuator to axially contract move a slide bar, extending through the elongate shaft and coupled to an articulation joint formed between the elongate shaft and the end effector, laterally and thereby effect pivotal movement of the end effector.  In other
embodiments, energy can be delivered to a first electroactive polymer actuator to move the end effector in a first direction, and to a second electroactive polymer actuator to move the end effector in a second, opposed direction.  The amount of energy
delivered to the electroactive polymer actuator can correspond to a degree of movement of the end effector.  In yet another embodiment, delivering energy to an electroactive polymer actuator can angularly position the end effector relative to the
elongate shaft by flexing a flexible portion extending between the elongate shaft and the end effector.  In another embodiment, the opposed jaws can be closed by delivering energy to an electroactive polymer actuator coupled to the opposed jaws to move
the opposed jaws from an open position to a closed position.
FIG. 13A is an illustration of another embodiment of an end effector having opposed jaws with first and second electroactive polymer actuators coupled thereto for moving the jaws between an open and closed position, showing the jaws in the closed
The present invention generally provides methods and devices for effecting movement of one or more components of a grasping device.  In one exemplary embodiment, the grasping device can include a shaft with an end effector coupled thereto and
having opposed jaws that are adapted to engage tissue or other objects therebetween.  An electrically expandable and contractible actuator, such as an electroactive polymer actuator, can be used to actuate the end effector, i.e., to move the jaws between
an open and closed position.  The end effector can also, in other embodiments, be movably coupled to a distal end of a shaft such that the end effector can be angularly oriented relative to the shaft.  An electrically expandable and contractible motor,
such as an electroactive polymer actuator, can be used to angularly adjust a position of the end effector relative to the shaft by delivering energy to the electroactive polymer actuator.  A person skilled in the art will appreciate that the grasping
device can have a variety of configurations, and that the electroactive polymer actuators disclosed herein can be incorporated into virtually any grasping device known in the art to effect actuation and/or articulation of an end effector.  Moreover, the
term &quot;grasping device&quot; is intended to include any device that has opposed pivoting jaws that come together to grasp, clamp, cut, dissect, etc. Other exemplary &quot;grasping devices&quot; include, by way of non-limiting example, surgical scissors, clamps, and
dissector devices.
FIGS. 1A-1B illustrate one exemplary embodiment of an EAP actuator 100 formed from a fiber bundle.  As shown, the actuator 100 generally includes a flexible conductive outer sheath 102 that is in the form of an elongate cylindrical member having
opposed end caps 102a, 102b formed thereon.  The outer sheath 102 can, however, have a variety of other shapes and sizes depending on the intended use.  As is further shown, the outer sheath 102 is coupled to an energy delivering electrode 108a and a
return electrode 108b.  In the illustrated embodiment, the energy delivering electrode 108a extends through one of the end caps, e.g., end cap 102a, through the inner lumen of the conductive outer sheath 102, and into the opposed end cap, e.g., end cap
102b.  The energy delivering electrode 108a can be, for example, a platinum cathode wire, and it can be coupled to any portion of the outer sheath 102.  The conductive outer sheath 102 can also include an ionic fluid or gel 106 disposed therein for
FIGS. 2A-2B illustrate an exemplary configuration of an EAP actuator 200 formed from a laminate.  Referring first to FIG. 2A, the actuator 200 can include multiple layers, e.g., five layers 210, 210a, 210b, 210c, 210d are shown, of a laminate EAP
composite that are affixed to one another by adhesive layers 103a, 103b, 103c, 103d disposed therebetween.  One of the layers, i.e., layer 210, is shown in more detail in FIG. 2B, and as shown the layer 210 includes a first flexible conductive plate
As previously indicated, in an exemplary embodiment surgical grasping methods and devices are provided that utilize electrically expandable and contractible actuators, such as EAP actuators, to effect articulation and/or actuation of various
components of the device.  The various methods and devices disclosed herein for effecting articulation and actuation can be incorporated into virtually any grasping device known in the art, and the grasping device can include a variety of other features
known in the art and not disclosed herein.  FIG. 3 illustrates one exemplary embodiment of a grasping device 10 that can include one or more EAP actuators for effecting articulation and/or actuation.  A person skilled in the art will appreciate that,
while the various embodiments are described as having EAP actuators for affecting articulation and/or actuation without mechanical assistance, the actuators can alternatively be configured to supplement mechanical articulation and/or actuation.
In general, as shown in FIG. 3, the grasping device 10 includes a shaft 12 having a handle housing 14 coupled to a proximal end 12a thereof, and an end effector 11 coupled to the distal end 12b thereof.  The end effector 11 includes opposed first
and second jaws 16, 18 having teeth formed thereon and at least one EAP actuator for moving the jaws 16, 18 to grasp tissue or other objects therebetween.  The handle housing 14 can include a trigger, such as a pivoting handle, rotatable knob, button,
switch, sliding lever, or other mechanism formed thereon for actuating electrical energy delivery to the EAP actuator(s).  In use, an object, such as tissue, is positioned between the first and second jaws 16, 18, and the first and second jaws 16, 18 are
moved from an open position to a closed position to engage the object.  The end effector 11 can also optionally be pivoted relative to the shaft 12 to facilitate positioning of the object therein.  The grasping device 10 is particularly suitable for
endoscopic and laparoscopic procedures, as the relatively small diameter of the shaft 12 allows it to fit through small access ports or pathways.  The grasping device, however, can be adapted for use in a variety of medical procedures.
As indicated above, one or more EAP actuators can be used to actuate the jaws 16, 18.  While the EAP actuator can have a variety of configurations, FIGS. 4A-5 illustrate various exemplary configurations of EAP actuators used to open and close the
jaws of a surgical grasping device.  As will be discussed in more detail below, the EAP actuator(s) can be configured to move the jaws from an open position to a closed position or from a closed position to an open position.
FIGS. 4A-4B illustrate one exemplary embodiment of a technique for opening and closing first and second jaws of an end effector using EAP actuators.  In this embodiment, which illustrates the end effector 11 of FIG. 3 in more detail, first and
second EAP actuators 60a, 60b are used to move the jaws 16, 18 from an open position to a closed position.  In general, the first and second jaws 16, 18 can be pivotally coupled to one another at a pivot point 23 formed between a proximal portion 16a,
18a and a distal portion 16b, 18b of each jaw 16, 18, i.e., the pivot point 23 is formed a distal apart from the proximal-most end of the jaws 16, 18.  Such a configuration allows the EAP actuators 60a, 60b to engage and move the proximal portion 16a,
18a of the jaws 16, 18 relative to one another, thereby moving the distal portion 16b, 18b of the jaws 16, 18 about the pivot point 23.  In particular, the first electroactive polymer actuator 60a extends between the proximal portion 16a of the first jaw
16 and a fixed point on the shaft 12, and the second electroactive polymer actuator 60b extends between the proximal portion 18a of the second jaw 18 and a fixed point on the shaft 12.  The fixed point can be located at a variety of locations on or
within the shaft 12.  In the illustrated embodiment, the fixed point is in the form of a pin 25 extending through the shaft 12, as shown in FIG. 4B.  A person skilled in the art will appreciate that, while two EAP actuators 60a, 60b are shown, a single
EAP actuator can extend from the proximal portion 16a of the first jaw 16, around the pin 25, and attach to the proximal portion 18a of the second jaw 18.  Moreover, the fixed point can be formed anywhere on, around, or within the shaft 12.
In use, energy can be selectively delivered to one or both of the first and second EAP actuators 60a, 60b through electrodes (not shown) extending through or along the shaft 12.  The electrodes can couple to an energy source, such as a battery,
disposed within the handle housing 14, or they can couple to an external energy source, such as an external battery or an electrical outlet.  As a result of energy delivered to the actuators 60a, 60b, the actuators 60a, 60b will axially contract or
shorten, pulling the proximal portions 16a, 18a of the first and second jaws 16, 18 toward the shaft 12, thereby moving the distal portions 16b, 18b of the first and second jaws 16, 18 to the closed position such that the jaws 16, 18 can grasp the an
object, such as tissue, that is positioned therebetween.  When energy delivery is terminated, the actuator cords 60a, 60b axially expand and return to their initial position, which allows the proximal and distal portions 16a, 18a, 16b, 18b of the jaws
16, 18 to move to the open position.  While not shown, the device can also include a biasing element, such as a spring, for biasing the jaws 16, 18 to the open position.  Thus, when energy delivery to the EAP actuators 60a, 60b is terminated, the biasing
element will facilitate movement of the jaws 16, 18 to the open position.
FIG. 5 illustrates another exemplary embodiment of a technique for opening and closing the jaws of an end effector using EAP actuators.  In this embodiment, the grasping device 500 is similar to the grasping device 400 shown in FIGS. 3-4B,
however the grasping device 500 has jaws 516, 518 that are biased to the closed position and the EAP actuator is effective to move the jaws 516, 518 to the open position when energy is delivered thereto.  In particular, as shown in FIG. 5, each jaw 516,
518 includes a distal engaging portion 516b, 518b and a proximal portion 516a, 518a that extends transverse to the distal portion 516b, 518b and that diverge relative to one another.  An EAP actuator 560 extends between the proximal portions 516a, 518b
of the first and second jaws 516, 518 at a location proximal to the pivot point 523 to allow the jaws 516, 518 to pivot about the pivot point 523 when the EAP actuator 560 is actuated.
In use, energy can be delivered to the electroactive polymer actuator 560 through electrodes extending though the shaft 512 and coupled to a power source that is disposed within or mated to the handle housing of the device.  The energy will cause
the electroactive polymer actuator 560 to axially contract, pulling the proximal portions 516a, 518b of the jaws 516, 518 toward one another and toward the shaft 12, thereby moving the distal portions 516b, 518b of the first and second jaws 516, 518 away
from one another to an open position such that an object can be positioned between the jaws 516, 518.  Termination of energy delivery will cause the electroactive polymer actuator 560 to axially expand and return to the unactuated position, which allows
the proximal potions 516a, 518a of the jaws 516, 518 to move away from one another such that the distal portions 516b, 518b of the jaws 516, 518 can close.  While not shown, the device can also include a biasing element, such as a spring, that can bias
the jaws 16, 18 to the closed position.
FIGS. 13A and 13B illustrate another embodiment of a technique for opening and closing opposed jaws of an end effector of a grasping device.  In this embodiment, the jaws 90 are formed from a shape memory material such that they are biased to the
closed position.  First and second EAP actuators 92a, 92b extend between a proximal end of each jaw and a base of each jaw, i.e., adjacent to the pivot point of the jaws 90.  The actuators 92a, 29b can extend at an angle relative to the jaws 90, i.e.,
the actuators 92a, 92b can diverge from one another from the base to the ends of the jaws 90.  As a result, when energy is delivered to the EAP actuators 92a, 92b, the EAP actuators 92a, 92b can axially contract or shorten to apply a force to the ends of
the jaws 90, thereby opening the jaws, as shown in FIG. 13B.
As noted above, the EAP actuators can have a variety of configurations.  In the embodiments shown FIGS. 4A-5 each EAP actuator is in the form of a fiber-bundle type EAP actuator cord, which can be formed from a single EAP fiber strand, or
multiple EAP fibers woven or braided together to form a cord.  In other embodiments, each EAP actuator can be in the form of a laminate or composite EAP.  A person skilled in the art will appreciate the variety of actuator configurations that can be used
to effect movement of the first and second jaws.
As previously indicated, the present invention also provides exemplary methods and devices for articulating an end effector (i.e., opposed jaws) of a grasper.  FIGS. 6A-12B illustrate various exemplary embodiments of articulation joints and
electroactive polymer actuators for effecting articulation.  These articulation joints can be incorporated into any grasper, including those exemplary prior art instruments described above.
Referring first to FIGS. 6A-6B, a distal end 612b of the elongate shaft 612 is shown coupled to a proximal end of the end effector 611 by a pivot joint 616, such that the end effector 611 can pivot relative to the shaft 612 about the pivot joint
616.  The device also includes a slide bar 624 extending through the elongate shaft 612 and having a distal end 624d with gear teeth 624t formed thereon and adapted to engage corresponding gear teeth 616t formed on the end effector 611.  The device can
also include one or more electrically expandable and contractible actuators, such as an EAP actuator, for moving the slide bar 624 to cause the gear teeth 624t on the slide bar 624 to move the gear teeth 624t on the end effector 611 and thereby pivot the
end effector 611 relative to the elongate shaft 612.  While the EAP actuator(s) can effect movement of the slide bar 624 using a variety of techniques, in one exemplary embodiment the EAP actuators are configured to move the slide bar 624 laterally.  In
particular, a first EAP actuator 626a can extend through at least a portion of the elongate shaft 612 adjacent to a first lateral side of the slide bar 624, and a second EAP actuator 626b can extend through at least a portion of the elongate shaft 612
adjacent to a second, opposed lateral side of the slide bar 624, as shown in FIGS. 6A-6B.  Either type of EAP actuator can be used, but in an exemplary embodiment the EAP actuators 626a, 626b are laminate type EAP actuators that are adapted to expand
laterally when energy is delivered thereto.  FIG. 6A illustrates both actuators 626a, 626b in a non-expanded, un-actuated configuration, where no energy is delivered to either actuator 626a, 626b.  FIG. 6B illustrates the first EAP actuator 626a
laterally expanded to move the slide bar 624 laterally toward the second EAP actuator 626b, thereby causing the slide bar 624 to pivot the end effector 611 in a direction opposite to the direction of movement of the slide bar 624.  Energy can be
delivered to the actuators 626a, 626b through electrodes extending through the shaft 612 and coupled to an energy source disposed within or coupled to a handle of the device, e.g., a battery source or an electrical outlet or other energy source.  The
handle can also include a control mechanism, such as a sliding lever, rotatable knob, or dial, coupled thereto and adapted to control the amount of energy delivered to each actuator 626a, 626b.  The amount of energy delivered to each actuator 626a, 626b
is determinative of the amount of expansion of the actuators 626a, 626b, thus allowing the amount of pivotal movement of the end effector 611 to be selectively adjusted.
A person skilled in the art will appreciate that, while FIGS. 6A-6B illustrate a laterally-moving slide bar 624 with laterally expanding EAP actuators 626a, 626b, the slide bar 624 and actuators 626a, 626b can have a variety of other
configurations.  For example, multiple EAP actuators in the form fiber bundles can extend laterally between an inner surface of the elongate shaft 612 and the slide bar 624.  When energy is delivered to the actuators, the actuators can contract or
shorten in length to pull the slide bar 624 toward the elongate shaft 612, thereby moving the slide bar 624 laterally.  Alternatively, the slide bar 624 can be configured to move longitudinally to effect movement of the end effector 611, and the EAP
actuator can be used to effect longitudinal movement of the slide bar 624.  In other embodiments, the slide bar itself, or at least a portion of the slide bar, can be formed from an EAP actuator that is adapted to expand axially in a desired direction to
move the slide bar laterally.
FIGS. 7A-7B illustrate another embodiment of a technique for articulating an end effector of a surgical grasper device.  In this embodiment, the end effector 711 is pivotally coupled to the elongate shaft 712 by first and second opposed arms
790a, 790b coupled to opposed sides of the elongate shaft 712.  First and third EAP actuators 726a, 726c are attached to and extend from opposed sides of a terminal end of the first arm 790a, and second and fourth EAP actuators 726b, 726d are attached to
and extend from opposed sides of a terminal end of the second arm 790b.  The distal end of each EAP actuator 726a-d is coupled to an inner sidewall of the elongate shaft 712 at an attachment point (first, second, and third attachment points 792a, 792b,
792c are shown).  As a result, the first and second actuators 726a and 726b are attached to one side of the elongate shaft 712, and the third and fourth actuators 726c and 726d are attached to an opposite side of the elongate shaft 712.  In use, energy
can be delivered to the first and second EAP actuators 726a, 726b to cause the actuators 726a, 726b to axially contract or shorten, thereby pulling the first and second arms 790a, 790b in a lateral direction towards the first and second attachment points
792a, 792b.  As a result, the end effector 711 is pivoted in a first direction.  When energy delivery is terminated, the first and second actuators 726a, 726b will axially expand returning to their initial configuration, thereby moving the end effector
711 to its initial position in which it is longitudinally aligned with the elongate shaft 712.  Energy can be delivered to the third and fourth actuators 726c, 726d to similarly move the end effector 711 in an opposite direction.  As previously
discussed, the amount of energy delivered can be controlled to control the amount of pivotal movement of the end effector 711.  As shown in FIG. 7B, the device can also include a covering 799 surrounding at least a portion of the pivot frame assembly 757
to provide support thereto.
FIG. 8 illustrates yet another embodiment of a technique for articulating an end effector of a surgical grasper device.  In this embodiment, one or more actuating members can be incorporated into a pulley 898 that is part of a pivoting frame
assembly 857.  The pulley 898 can be made entirely of EAP actuators or, alternatively, EAP actuators can be attached to proximal and distal ends of the pulley 898.  In the illustrated embodiment, first and second EAP actuators 826a, 826b are attached to
the proximal and distal ends of the pulley 898.  The EAP actuators 826a, 826b are anchored to the elongate shaft 812 to push and pull the end effector 811 to effect articulation.  In particular, energy delivery to one of the EAP actuators, e.g., the
first EAP actuator 826a, causes the first EAP actuator 826a to axially contract or shorten to move the pulley 898 in a first direction, thereby causing the end effector 811 to pivot in a first direction.  Conversely, energy delivery to the second EAP
actuator 826b causes the second EAP actuator to axially contract or shorten to move the pulley 898 in a second, opposite direction, thereby causing the end effector 811 to pivot in a second, opposite direction.  Again, energy delivery can be controlled
to control the amount of movement of the end effector 811.
FIGS. 9A-9B illustrate another embodiment of a technique for articulating an end effector relative to an elongate shaft of a grasper.  In this embodiment, the elongate shaft 912 includes a slide bar 924 extending therethrough and having a ball
924t formed on a distal end thereof and received within a corresponding socket 916s formed in a proximal end of the end effector 911.  The slide bar 924 also includes cam surfaces 925a, 925b formed thereon, preferably at a location proximal to the distal
end of the elongate shaft 912.  The cam surfaces 925a, 925b can have a variety of shapes and sizes, but in an exemplary embodiment, as shown, the cam surfaces 925a, 925b extend outward from opposed sides of the slide bar 924 and they are wedge-shaped
members that increase in width in a proximal-to-distal direction.  The device also includes first and second actuating members 926a, 926b extending through the elongate shaft 912 and positioned on opposed sides of the slide bar 924.  Each actuating
member 926a, 926b includes a cam surface 927a, 927b formed thereon and adapted to abut against the cam surfaces 925a, 925b formed on the slide bar 924.  As a result, distal movement of the first actuating member 926a will cause the cam surface 927a
formed thereon to slide against the cam surface 925a formed on the slide bar 924, thereby moving the slide bar 924 laterally away from the first actuating member 926a.  As a result of the lateral movement of the slide bar 924, the ball 924t will cause
the end effector 911 to pivot relative to the elongate shaft 912.  Conversely, distal movement of the second actuating member 926b will cause the cam surface 927b formed thereon to slide against the cam surface 925b formed on the slide bar 924, thereby
moving the slide bar 924 laterally away from the second actuating member 926b, and thus pivoting the end effector 911 in an opposite direction.  A biasing element (not shown), such as a spring, can be disposed on each side of the slide bar 924 to bias
the slide bar 924 to the central, resting position shown in FIG. 9A, thereby allowing the slide bar 924 to return to the resting position when the actuating members 926a, 926b are moving proximally.
In an exemplary embodiment, movement of each actuating member 926a, 926b can be achieved using an EAP actuator coupled thereto.  As shown in FIGS. 9A and 9B, an EAP actuator cord 926a&#39;, 926b&#39;, preferably in the form of a fiber bundle type
actuator, extends between a distal end of each actuating member 926a, 926b and a distal end of the shaft 912.  When energy is selectively delivered to one of the EAP actuating cords, e.g., the first actuating cord 926a&#39;, the cord 926a&#39; will axially
contract or shorten, as shown in FIG. 9B, thereby pulling the actuating member 926a coupled to the actuated EAP cord 926a&#39; in a distal direction.  The cam surface 927a on the actuating member 926a will abut against the cam surface 925a on the slide bar
924 to move the slide bar 924 laterally toward the second actuating member 926b.  As a result, the ball 924t on the distal end of the slide bar 924 will cause the end effector 911 to articulate or pivot thereabout.
A person skilled in the art will appreciate that the EAP actuators can have a variety of other configurations, and they can effect movement of the slide bar using a variety of other techniques.  For example, rather than pulling the slide bar 924
distally when energy is delivered to the EAP actuating cords 926a&#39;, 926b&#39;, the EAP actuators can be coupled to a proximal end of the slide bar 924 and they can be adapted to push the slide bar 924 distally.  In other embodiments, the cam surface 927a,
927b formed on each actuating member 926a, 926b can be formed from an EAP actuator such that energy delivery to the cam surface 927a, 927b causes the cam surface 927a, 927b to expand toward the slide bar 924, thereby moving the slide bar 924 in a desired
direction to articulate the end effector 911.  The amount of movement of each actuating member 926a, 926b, and thus the amount of articulation of the end effector, can also be controlled by controlling the amount of energy delivered to each EAP actuator.
FIGS. 10A-10B illustrate yet another embodiment of a technique for articulating an end effector 1012 of a grasper.  In this embodiment, rather than using a slide bar to pivot the end effector 1012, two actuating members 1026a, 1026b are coupled
directly to opposed sides of the end effector 1012 to push and pull the end effector 1012 to effect articulation.  In particular, a distal end of each actuating member 1026a, 1026b is coupled to a proximal end of the end effector 1012 by a pivot joint,
such that proximal movement of the first actuating member 1026a causes the end effector 1012 to pivot about the second actuating member 1026b, and proximal movement of the second actuating member 1026b causes the end effector 1012 to pivot about the
first actuating member 1026a.  The actuating members 1026a, 1026b can be moved using a variety of techniques.  For example, all or a portion of each actuating member 1026a, 1026b can be formed from an EAP that is adapted to axially expand, or the
actuating members 1026a, 1026b can be coupled to an EAP actuator for moving the actuating members 1026a, 1026b proximally and distally to articulate the end effector 1012.
FIG. 11 illustrates another embodiment of a technique for articulating an end effector of a grasper device.  In this embodiment, the elongate shaft 1120 includes a flexible portion formed by a plurality of cut out portions 1122, 1124, 1126, 1128,
1130, 1132, 1134, 1136, 1138, 1140, 1142 (hereinafter 1122-1142) formed on opposed sides of the elongate shaft 1120.  The cut out portions allow the elongate shaft 1120 to flex thereabout.  One or more actuators can be positioned relative to the cut out
portions to effect pivotal or bending movement of an end effector (not shown) relative to the elongate shaft 1120.  FIG. 11 illustrates multiple EAP actuator cords 1144, 1146, 1148, 1150, 1152, 1154 (hereinafter 1144-1154) extending longitudinally
through the elongate shaft 1120 where the cut out portions are formed.  The EAP actuator cords 1144-1154 extend longitudinally parallel to one another, and they are coupled to the elongate shaft 1120 at a first end just proximal to the cut out portions
1122-1142 and at a second end just distal to the cut out portions 1122-1142.  In use, energy can be selectively delivered to any one or combination of the EAP actuator cords 1144-1154 to flex the cut out portions 1122-1142 and thereby articulate the end
effector in a desired direction.  For example, energy can be delivered to the first EAP actuator cord 1144 to cause the first actuator cord 1144 to axially contract or shorten, thereby pulling the opposed ends of the cord 1144 toward one another.  Since
the ends of the first actuator cord 1144 are attached to the elongate shaft 1120 at opposed ends of the cut out portions, and since the first EAP actuator cord 1144 is offset from a central axis of the elongate shaft 1120, the first EAP actuator cord
1144 will cause the elongate shaft 1120 to bend in a first direction.  Accordingly, one or more actuator cords 1144-1154 can be selectively activated, i.e., energy can be selectively delivered thereto, to effect movement of the end effector in a desired
direction.  A person skilled in the art will appreciate that a variety of other techniques can be used to cause the cut out portions to bend.
In other embodiments, one or more EAP actuators can be positioned within, on, or around the flexible portion of the elongate shaft at various locations, and the EAP actuators can be configured to flex the flexible portion when energy is delivered
to the actuators, thereby articulating the end effector.  For example, multiple EAP actuators can extend axially along distinct portions of a flexible portion of an elongate shaft, or they can be positioned at various other locations around the
circumference of the flexible portion.  In use, energy delivery to a first actuator, for example, to cause the first actuator to axially contract thereby bending a portion of the flexible portion.  A user can thus selectively deliver energy to one or
more actuators to articulate and position the end effector as desired.
A person skilled in the art will appreciate that any of the above embodiments can include a locking feature that allows the device to maintain its articulated position when energy delivery is terminated to the EAP actuators.  In particular, when
energy delivery is terminated the EAP actuator(s) axially expands to return the end effector to its initial position in which it is longitudinally aligned with the elongate shaft.  A locking mechanism can thus be used to lock the end effector in a
desired articulated position prior to terminating energy delivery to the EAP actuators.
While the locking mechanism can have a variety of configurations, FIGS. 12A-12B illustrate one exemplary embodiment of an articulation lock 1270 that is incorporated into a pivoting articulation joint 1262.  As shown, the articulation joint 1262
includes a rotary structure 1272 having a plurality of holes 1264a, 1264b, 1264c, 1264d, 1264e that are adapted to receive a plunger to prevent rotational movement of the articulation joint 1262.  A stop, which in one embodiment can be a spring loaded
plunger 1266, is formed within the elongate shaft of the device and located proximal to the rotary structure 1272.  The plunger 1266 is also coupled to an EAP actuator (not shown) that, when actuated with energy, effects movement of the plunger 1266
thereby allowing the articulation joint 1262 to move.  In particular, as shown in FIG. 12A, when the device is in an un-actuated position, the plunger 66 rests in one of the holes (hole 64e as shown) of the rotary structure 1272, thereby maintaining the
end effector in a fixed position.  Energy delivery to the EAP actuator, as shown in FIG. 12B, will pull the plunger 1266 out of the hole 1264e to allow the articulation joint 1262 to move to a desired position.  The various techniques previously
described can be used to articulate the end effector.  Once the end effector is moved to a desired articulated position, the EAP actuator can be de-actuated, i.e., energy delivery can be terminated, allowing the spring to bias the plunger 1266 into one
of the holes of the rotary structure 1272.  The end effector is thereby again maintained in a fixed position.  One skilled in the art will appreciate that a variety of other locking mechanism can be incorporated into an articulating joints, such as a
ratchet and teeth system.
A person skilled in the art will appreciate that the EAP actuators can have a variety of other configurations to effective movement of the plunger.  For example, in another embodiment an EAP actuator can replace the plunger and can be directly
connected to a driver to move the driver distally through the elongate shaft.  One skilled in the art will appreciate further features and advantages of the invention based on the above-described embodiments.  Accordingly, the invention is not to be
limited by what has been particularly shown and described, except as indicated by the appended claims.  All publications and references cited herein are expressly incorporated herein by reference in their entirety.
Electroactive polymer-based articulation mechanism for grasper, Ortiz, et al., Mark Ortiz, Frederick Shelton IV, Jeffrey Swayze, Application number 11 162-991, Surgery, Elongated-Member-Driving Apparatus, surgical instrument, Surgical stapling, Work File, Surgical stapler, wherein said, Tyco Healthcare Group, head assembly, Ethicon Endo-Surgery, staple cartridge, Patent Drawings
The present invention relates broadly to surgical devices, and in particular to methods and devices for articulating and/or actuating a grasping device.BACKGROUND OF THE INVENTIONEndoscopic surgical instruments are often preferred over traditional open surgical devices since a smaller incision tends to reduce the post-operative recovery time and complications. Consequently, significant development has gone into a rangeof endoscopic surgical instruments that are suitable for precise placement of a distal end effector at a desired surgical site through a cannula of a trocar. These distal end effectors engage the tissue in a number of ways to achieve a diagnostic ortherapeutic effect (e.g., endocutter, grasper, cutter, staplers, clip applier, access device, drug/gene therapy delivery device, and energy device using ultrasound, RF, laser, etc.).Known surgical graspers include an end effector that can be actuated to grasp tissue or other devices or objects. The end effector includes a pair of cooperating jaw members that, if the instrument is intended for endoscopic or laparoscopicapplications, are capable of passing through a cannula passageway. The jaws can then be opened and closed to grasp and manipulate tissue. Some devices have end effectors that can be pivotally coupled to the shaft or a shaft that can be flexiblerelative to the end effector to allow the end effector to be angularly oriented to facilitate grasping of tissue. One drawback to such articulating devices, however, is that a mechanical linkage is used to transfer a force from a handle of the device tothe end effector to activate the end effector. The mechanical linkage can interfere with the pivoted or curved orientation of the shaft, potentially causing it to straighten.Accordingly, there remains a need for methods and devices for actuating and/or articulating a surgical grasper.BRIEF SUMMARY OF THE INVENTIONThe present invention generally provides methods and devices for articulating and/or act
Fundamental investigations of ultrathin carbon In particular we are examining how these electroactive polymer coatings as components self limiting films differ from