U.S. patent application number 15/946612 was filed with the patent office on 2018-08-09 for end-effector jaw closure transmission systems for remote access tools.
The applicant listed for this patent is Shorya AWTAR, Peter F. COSTA, Christopher K. HOLMES, Bruce JOHNSON, Ryan Brook RANK, Zachary ZIMMERMAN. Invention is credited to Shorya AWTAR, Peter F. COSTA, Christopher K. HOLMES, Bruce JOHNSON, Ryan Brook RANK, Zachary ZIMMERMAN.
Application Number | 20180221045 15/946612 |
Document ID | / |
Family ID | 58446588 |
Filed Date | 2018-08-09 |
United States Patent
Application |
20180221045 |
Kind Code |
A1 |
ZIMMERMAN; Zachary ; et
al. |
August 9, 2018 |
END-EFFECTOR JAW CLOSURE TRANSMISSION SYSTEMS FOR REMOTE ACCESS
TOOLS
Abstract
A jaw closure transmission system is presented comprising an
input sub-system, output sub-system and a transmission
sub-system.
Inventors: |
ZIMMERMAN; Zachary;
(Waterford, MI) ; AWTAR; Shorya; (Ann Arbor,
MI) ; JOHNSON; Bruce; (Elkins, NH) ; HOLMES;
Christopher K.; (Harvard, MA) ; COSTA; Peter F.;
(Winthrop, MA) ; RANK; Ryan Brook; (Brighton,
MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ZIMMERMAN; Zachary
AWTAR; Shorya
JOHNSON; Bruce
HOLMES; Christopher K.
COSTA; Peter F.
RANK; Ryan Brook |
Waterford
Ann Arbor
Elkins
Harvard
Winthrop
Brighton |
MI
MI
NH
MA
MA
MI |
US
US
US
US
US
US |
|
|
Family ID: |
58446588 |
Appl. No.: |
15/946612 |
Filed: |
April 5, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/US2016/055606 |
Oct 5, 2016 |
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15946612 |
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62237476 |
Oct 5, 2015 |
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62237483 |
Oct 5, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 34/76 20160201;
A61B 2017/0069 20130101; A61B 34/30 20160201; B25J 9/06 20130101;
A61B 34/71 20160201; A61B 2017/00314 20130101; B25J 9/104 20130101;
A61B 2017/00323 20130101; B25J 9/065 20130101; A61B 2034/715
20160201; A61B 2034/306 20160201; A61B 2090/031 20160201; A61B
1/005 20130101 |
International
Class: |
A61B 17/29 20060101
A61B017/29; A61B 17/04 20060101 A61B017/04; A61B 17/062 20060101
A61B017/062; A61B 90/11 20060101 A61B090/11; A61B 34/00 20060101
A61B034/00 |
Claims
1. A medical device having a jaw assembly actuated by a
transmission cable having a finite stiffness in a transmission
direction, the device comprising: an elongate transmission guide,
wherein the transmission cable is routed through the transmission
guide; a handle assembly at a proximal end of the elongate
transmission guide, the handle assembly comprising a handle body,
an input lever, a handle output coupled to the transmission cable,
and a handle mechanism coupling the input lever to the handle
output, wherein the handle mechanism has an input stroke consisting
of a full closure displacement of the input lever relative to the
handle body, further wherein the input stroke is divided into a
first part and a second part, wherein the first part corresponds to
a displacement of 30% to 70% of the full closure displacement of
the input lever and the second part corresponds to the remaining
displacement of the input lever; and wherein the jaw assembly is
distal to the elongate transmission guide, the jaw assembly having
a first jaw, a second jaw, a jaw input coupled to the transmission
cable, and a jaw mechanism coupling the jaw input to the second
jaw, wherein the jaw mechanism has an open configuration when the
first and second jaws are fully open relative to each other and a
closed configuration when the first and second jaws are fully
closed; further wherein the displacement of the input lever
relative to the handle body corresponding to the first part of the
input stroke actuates the handle output which in turn actuates the
jaw input via the transmission cable, which in turn closes the
first and second jaws until the first and second jaws reach a hard
stop, and thereafter the displacement of the handle lever relative
to the handle body corresponding to the second part of the input
stroke stretches the transmission cable, wherein the resulting
tension in the transmission cable is converted by the jaw mechanism
to a holding force between the first and second jaws.
2. The device of claim 1, wherein the handle mechanism comprises a
linkage or a cam.
3. The device of claim 1, wherein the handle mechanism comprises a
six-bar linkage.
4. The device of claim 1, wherein the elongate transmission guide
comprises a flexible conduit or elongate shaft or both.
5. The device of claim 1, wherein the transmission cable has a
stiffness in a transmission direction of less than 650 pounds per
inch.
6. The device of claim 1, wherein handle mechanism is configured to
provide a first mechanical advantage during the first part of the
input stroke and a second mechanical advantage that is greater than
the first mechanical advantage during the second part of the input
stroke.
7. The device of claim 1, wherein the handle output comprises one
or more of: a shuttle, a push rod, or a pull rod.
8. The device of claim 1, further comprising a jaw base to which
either or both the first and second jaws are pivotally coupled.
9. The device of claim 1, wherein the jaw input comprises a jaw
pulley, and the jaw mechanism comprises a cam surface between the
jaw pulley and the second jaw.
10. The device of claim 1, further comprising a releasable latching
mechanism configured to hold the handle lever locked in a closed
position at the end of the input stroke.
11. A method of operating a medical device to close a jaw assembly
of the medical device, wherein the medical device comprises an
elongate transmission guide, a finite stiffness transmission cable
within the transmission guide, and a handle assembly at the
proximal end of the elongate transmission guide having an input
lever and a handle mechanism coupling the input lever to the
transmission cable, wherein the transmission cable is coupled to a
jaw input of the jaw assembly, wherein the jaw assembly is distal
to the elongate transmission guide, the method comprising:
actuating the input lever to apply tension to the transmission
cable during a first part of an input stroke of the handle assembly
to close a first and second jaw of the jaw assembly from an open
configuration until the first and second jaws reach a hard stop;
and continuing to actuate the input lever during a second part of
the input stroke after the first and second jaws have reached the
hard stop and stretching the transmission cable; wherein the input
stroke consists of a full displacement of the handle lever of the
handle assembly, and further wherein the handle assembly
transitions from the first part of the input stroke to the second
part of the input stroke when the handle is between 30% and 70%
displaced.
12. The method of claim 11, further comprising applying a first
mechanical advantage during the first part of the input stroke and
applying a second mechanical advantage that is greater than the
first mechanical advantage during the second part of the input
stroke.
13. The method of claim 11, further comprising grasping an object
between the first and second jaws, wherein the first and second
jaws reach the hard stop when the object is secured between the
first and second jaws.
14. The method of claim 11, further comprising locking the input
lever in a fully closed position relative to a handle shell in the
handle assembly.
15. The method of claim 11, further comprising releasing the input
lever to transition the handle lever from the second part of the
input stroke to the first part of the input stroke, reducing the
tension on the transmission cable and reducing the stretch of the
transmission cable before translating the transmission cable so
that the first and second jaws open.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation of International
Application No. PCT/US2016/055606, filed Oct. 5, 2016, titled
"END-EFFECTOR JAW CLOSURE TRANSMISSION SYSTEMS FOR REMOTE ACCESS
TOOLS," now International Publication No. WO 2017/062529, which
claims priority to U.S. Provisional Patent Application No.
62/237,476, titled "END-EFFECTOR JAW CLOSURE TRANSMISSION SYSTEMS
FOR REMOTE ACCESS TOOLS," and filed on Oct. 5, 2015; and to U.S.
Provisional Patent Application No. 62/237,483, titled "ARTICULATING
JOINT AND SUPPORTING MEMBER THEREOF," and filed on Oct. 5, 2015.
Each of which is herein incorporated by reference in its
entirety.
[0002] This application may also be related to U.S. patent
application Ser. No. 15/130,915, titled "ATTACHMENT APPARATUS FOR
REMOTE ACCESS TOOLS", and filed on Apr. 15, 2016, which claimed
priority to U.S. Provisional Patent Application No. 62/147,998,
filed Apr. 15, 2015 (and titled "FOREARM ATTACHMENT APPARATUS FOR
REMOTE ACCESS TOOLS"), and U.S. Provisional Patent Application No.
62/236,805, filed Oct. 2, 2015 (titled "FOREARM ATTACHMENT
APPARATUS FOR REMOTE ACCESS TOOLS"). This application may also be
related to U.S. patent application Ser. No. 15/054,068, filed on
Feb. 25, 2016, and titled "PARALLEL KINEMATIC MECHANISMS WITH
DECOUPLED ROTATIONAL MOTIONS" which claims priority as a OP to U.S.
patent application Ser. No. 14/166,503, filed on Jan. 28, 2014, and
titled "MINIMAL ACCESS TOOL," Publication No. US-2014-0142595-A1,
which is a continuation of U.S. patent application Ser. No.
12/937,523, filed on Apr. 13, 2009, now U.S. Pat. No. 8,668,702,
which claimed priority to U.S. provisional patent application No.
61/044,168, filed on Apr. 11, 2008. Each of these patents and
patent applications is herein incorporated by reference in its
entirety.
INCORPORATION BY REFERENCE
[0003] All publications and patent applications mentioned in this
specification are herein incorporated by reference in their
entirety to the same extent as if each individual publication or
patent application was specifically and individually indicated to
be incorporated by reference.
FIELD
[0004] Described herein are transmission systems that are used for
remote access instruments, for example minimally invasive surgical
tools. In particular the apparatus provides a transmission system
design that utilizes the transmission member as an energy storing
device, over a certain portion of input stroke, to achieve a
specific desired performance of the surgical tool. In general, the
transmission member may be referred to as a jaw closure
transmission member, or as a jaw closure transmission cable, or as
a transmission cable, or as a cable or the like.
BACKGROUND
[0005] Typically, in laparoscopic, endoscopic, or other minimally
invasive surgical procedures, a small incision or puncture is made
in a patient's body. A cannula is then inserted into a body cavity
through the incision, which provides a passageway for inserting
various surgical devices such as scissors, dissectors, retractors
or similar instruments. To facilitate operability through the
cannula, instruments adapted for laparoscopic surgery typically
embody a relatively narrow shaft supporting an end-effector (EE) at
its distal end and a lever or handle at its proximal end. Arranging
the shaft of such an instrument through the cannula allows a
surgeon to manipulate the proximal handle from outside the body to
cause the distal end-effector to carry out a surgical procedure at
a remote internal surgical site. In most embodiments, the handle
and tool shaft can be directly connected and roll rotation of the
entire handle may drive rotation of the entire tool shaft and
end-effector. Some alternative laparoscopic tools, such as, for
example, U.S. Pat. No. 8,668,702 includes a handle that is not
directly connected to the tool shaft but connected via an input
joint (e.g., comprising a pair of transmission strips) which still
allows for roll rotation of the tool shaft and end-effector by way
of handle rotation. In general, a handle body may be referred to as
a handle reference, or as a palm grip, handle shell, or the
like.
[0006] A laparoscopic or endoscopic instrument may provide a
surgeon with the ability to transfer high force loads from the
proximal end of the tool to the distal end. These forces are
transferred through the instrument through an input, output and
transmission member sub-system, where the sub-system consists of a
mechanism, as seen in most surgical instruments, such as U.S. Pat.
No. 5,330,502. The input mechanism generally consists of an
actuating lever body as an input and an output (for example, a
shuttle coupled to the handle body via a one Degree of Freedom
(DoF) slider joint). As a user actuates the handle lever, the
motion is transferred to the shuttle, and the amount that the
shuttle displaces is based on the input mechanism's mechanical
advantage, or transmission ratio. The terms transmission ratio and
mechanical advantage are both used in this document since the
transmission ratio and mechanical advantage are, in general, simply
the inverse of each other. When emphasizing force, the attribute
mechanical advantage is used, and when emphasizing displacement,
the attribute transmission ratio is used. Similarly, the output
mechanism can have a varying mechanical advantage, or transmission
ratio, over the output stroke. For a mechanical surgical instrument
which requires a high force output while not compromising on output
displacement, this varying mechanical advantage of both the input
mechanism and the output mechanism will have a certain desirable
profile. The mechanical advantage at the initial segment of the
stroke can be low because no force build up is required initially;
however the mechanical advantage at the end of the stroke needs to
be high to allow a reasonable force input to be amplified into a
large force output. The transmission members used in the prior art
are generally stiff in the direction of transmission. However, this
transmission member does not have to be rigid. In the transmission
systems described herein, the transmission member itself is
designed to have a finite stiffness so that it acts as an energy
storage member during certain portions of the input stroke of the
device. This offers a unique performance of the device and has many
benefits over rigid or highly stiff transmission members.
SUMMARY OF THE DISCLOSURE
[0007] Described herein are jaw closure transmission systems that
provide enhanced closure security and feel. These closure
transmissions may be part of any appropriate apparatus, including
medical devices (e.g., minimally invasive surgical tools), or any
other application in which it is beneficial or desirable to have a
jaw closure mechanism that may securely grip and provide feedback
to the user on grip strength, as will be described herein.
[0008] In general, the jaw closure transmission systems described
herein may include rigid and compliant transmission elements,
including an input (e.g., a jaw actuation input), an output (e.g.,
jaw mechanism), a transmission cable having a finite stiffness in a
transmission direction, and a rigid or flexible transmission
guiding element, wherein the transmission element stores energy
during closure transmission to achieve unique and desirable
functionality.
[0009] The jaw closure transmission systems described herein may
include three (or more) sub-systems that are serially connected
that take an input, in the form of handle lever displacement and
force from the user, and produce an output that presents as moving
jaw displacement and clamp load. In general, a moving jaw may be
referred as a movable jaw, or as an end-effector moving jaw, or as
an may be completely rigid in all directions, such as a frame, EE
moving jaw, or the like. The three sub-systems are as follows: (a)
input sub-system: handle assembly; (b) output sub-system: jaw
assembly; (c) transmission sub-system (e.g., transmission member,
e.g., cable, and transmission guide, e.g., flexible conduit). The
input sub-system may include the input in a handle assembly that
comprises a handle body or shell that serves as the local reference
or ground, and a handle lever configured to receive user input in
the form of closing or displacing the handle lever relative to the
handle body. In general, the full closure displacement of the
handle lever with respect to the handle body is referred to as the
input stroke. At full closure, i.e., at the end of an input stroke,
the handle lever reaches a hard-stop relative to the handle body.
At this hard stop, there may be a single locking or latching
feature that keeps the handle lever latched closed relative to the
handle body. An unlatching/unlocking feature (e.g., a releasable
lock) unlocks the handle lever and allows it to open again with
respect to the handle body.
[0010] The handle assembly may also include a handle output (handle
mechanism output) that connects to the transmission cable. The
handle output may be a shuttle, a push rod, a pull rod, etc. The
output typically interfaces with the transmission member and
provides an actuation motion to the proximal end of the
transmission member.
[0011] In general, the handle mechanism is configured as a
mechanical linkage system that translates the closing motion of the
handle lever relative to the handle body to a corresponding
actuation motion of the handle shuttle relative to the handle body.
The handle mechanism provides a transmission ratio and mechanical
advantage between the handle lever and the handle shuttle so as to
produce the appropriate actuation displacement and force at the
proximal end of the transmission member (e.g., appropriate cable
tension and cable displacement) via the handle shuttle during the
overall stroke of the handle lever (i.e., input stroke). This
optimization may be based on the structure and functionality of the
overall jaw closure transmission system including the input
sub-system, transmission sub-system, and output sub-system, and in
some variations may not be due to just the input sub-system.
[0012] The handle mechanism may be designed such that instead of
providing a constant mechanical advantage or transmission ratio, it
produces a higher transmission ratio (i.e., lower mechanical
advantage) in the first portion of the input stroke and a lower
transmission ratio (i.e., higher mechanical advantage) in the
second portion of the input stroke.
[0013] The output sub-system typically includes an end-effector
assembly or jaw assembly, and may include the following elements:
an end-effector (e.g., jaw) base or end-effector fixed jaw that
serves as the local reference or ground; an end-effector movable
jaw coupled to the end-effector fixed jaw (e.g., pivotally coupled
to the end-effector fixed jaw) such that it can open and close
(i.e., displace) with respect the end-effector fixed jaw.
[0014] The full closure displacement of the moving jaw relative to
the fixed jaw may be referred to as the output stroke; in the
devices described herein, the output stroke is always completed
prior to completion of the input stroke, and is generally completed
around the transition between the first portion of the input stroke
and the second portion of the input stroke (e.g., between about 30%
and 70% of the full input stroke, e.g., between about 40% and 60%
of the full input stroke, between about 40% and 70% of the full
input stroke, between about 45% and 60% of the full input stroke,
etc.).
[0015] In general, once the jaws have been closed either against
themselves or against an object grasped in the jaws, the jaws of
the jaw assembly are at a stop position, and will no longer close
further (full output stroke), by the action of the handle assembly
actuating the transmission cable. However, because the transmission
cable has a finite stiffness in a transmission direction (e.g., is
somewhat compliant), the handle assembly may continue to be
actuated in the second part of the input stroke, and may stretch
the transmission cable. This stretch may be felt by the user
operating the handle (as resistance in the handle) and the force
being applied to stretch the cable may be transmitted to the jaws
as a holding force between the jaws.
[0016] Thus, a closure displacement of the handle lever relative to
the handle body at the input of the closure transmission system may
result in a closure displacement of the moving jaw relative to the
fixed jaw to hold an object (such as a needle, suture, tissue,
staple, clip, etc.) between the jaws.
[0017] A pulley coupled to the fixed jaw (e.g., pivotally coupled
to the fixed jaw) may be configured to receive the actuation motion
from the distal end of the transmission member. The jaw assembly
may include a jaw mechanism, which may be a linkage, a cam (e.g.,
cam surface and pin), etc. The jaw mechanism (e.g., in some
variations a drive pin/cam surface) may translate the actuation
motion of the jaw pulley relative to the fixed jaw to a
corresponding closure motion of the moving jaw relative to the
fixed jaw.
[0018] In one example of the jaw mechanism, a drive pin is driven
by the pulley and interfaces with a camming surface on the moving
jaw, providing a camming action. In another example of the jaw
mechanism, the distal end of the transmission member (i.e., cable)
is wrapped around the pulley. To prevent a potential slippage
between the cable and the pulley, there is a positive engagement
feature between the cable and the pulley. This is accomplished via
a cylindrical member that is crimped onto the cable and sits in a
cavity on the pulley. The jaw mechanism is designed to provide a
transmission ratio and mechanical advantage between the distal end
of the transmission member and the moving jaw, so as to produce the
appropriate output displacement and force at the moving jaw
relative to the fixed jaw during the overall stroke of the moving
jaw (i.e., output stroke). This optimization may be based on the
structure and functionality of the overall closure transmission
system including the input sub-system, transmission sub-system, and
output sub-system, and not just the output sub-system.
Specifically, the jaw assembly (end-effector) mechanism may be
designed to provide a large mechanical advantage at the end of its
stroke, to maximally amplify the force in the transmission member
(i.e., tension in the jaw closure transmission cable) to a clamping
force at the jaws. This implies that for a certain desired jaw
clamping force, the transmission cable tension can be less, which
has several advantages.
[0019] The transmission sub-system may include a transmission
member to transmit the closure action of the input sub-system
(i.e., handle assembly) to the output sub-system (i.e., jaw
assembly) of the closure transmission system. More specifically,
the transmission member may transmit the actuation motion of the
handle shuttle to a corresponding actuation motion of the jaw
pulley. This transmission member may be a cable, braided rope, etc.
that is capable of accommodating very tight bends as might be
necessary when the closure transmission system is part of a remote
access tool or device.
[0020] The transmission member may be highly compliant (i.e.,
flexible) in bending, twisting, and compression. This member is
relatively stiffer in tension because it has to transmit force and
displacement along this direction; but at the same time, it is not
chosen or designed to be infinitely or effectively infinitely
stiff. Rather, it is intentionally designed or chosen to have a
finite stiffness (or finite compliance) so that it can also serve
as an inline spring. In general, nothing is infinitely stiff or
infinitely compliant; infinite stiffness corresponds to zero
compliance and zero stiffness corresponds to infinite compliance.
Instead, stiffness may be scaled on a relative scale. For example,
on some normalized scales a stiffness less than 10 is close to
infinitely compliant and a stiffness greater than 1000 is closely
to infinitely stiff. In any of the apparatuses described herein,
the axial stiffness of the transmission member may have a stiffness
in the range of 100.
[0021] Any of these apparatuses may include a transmission guide
that serves as a conduit or channel (also, a reference) for the
transmission member. The proximal portion of this transmission
guide is connected to the input sub-system reference (i.e., handle
body) and the distal portion of this transmission guide is
connected to the output sub-system reference (i.e., end-effector
fixed jaw). This guide may be completely rigid in all directions,
such as a frame, or a shaft, or tube. Alternatively, this guide may
be flexible in bending so that it can take an arbitrary, tortuous
shape but still remain very stiff (ideally, close to infinitely
stiffness) axially (i.e., along its bent/deformed central axis).
This guide may be flexible in bending so that it can take an
arbitrary, tortuous shape and have an intermediate stiffness (i.e.,
have some intentionally finite compliance) in the axial direction
(i.e., along its bent/deformed central axis).
[0022] The connections between the ends of the guide and respective
references of the input and output sub-systems maybe close to
infinitely stiff in the transmission direction (i.e., an axial
direction of the transmission cable) or may have some intentionally
finite compliance (i.e., slightly lower stiffness than infinitely
stiff values).
[0023] Collectively, the three coupled sub-systems may allow for
the use of cables as the primary transmission member. Cables are
highly flexible in bending and therefore can be incorporated within
minimal access tools/devices that have an input articulation joint
between the handle and the tool frame/shaft, and an output
articulation joint between the tool frame/shaft and the
end-effector. In such devices, the tool frame/shaft may also serve
as a portion of the transmission guide, or as the entire
transmission guide. In particular, the use of a cable transmission
member enables a very tight bend at the output articulation joint,
and also helps facilitate the miniaturization of the output
articulating joint, and therefore the miniaturization of the
end-effector as well at the distal end of the minimal access
tool/device.
[0024] Furthermore, the choice of a cable as a transmission member
and a flexible conduit as a transmission guide member facilitates a
minimal access tool/device architecture where the handle assembly
is not directly connected to a tool frame/shaft. Instead, in some
variations of the devices described herein, the handle assembly
"floats" with respect to the tool shaft/frame, and may be connected
via a virtual center input articulating joint that is proximal to
the handle assembly. The system (apparatus) may include a flexible
conduit as the transmission guide member to guide the transmission
member (cable) from the handle assembly to the tool
shaft/frame.
[0025] Furthermore, the choice of a cable as the jaw closure
transmission member in an articulating minimal access tool/device
may also ensure a relative decoupling between the jaw closure
functionality of the device, and articulation functionality of the
device. Since the transmission member itself does not have
significant bending (i.e., articulation) stiffness, it does not
significantly impact the articulation of the end-effector assembly
(jaw assembly) about the output articulation joint. Moreover, a
large mechanical advantage in the jaw mechanism may result in a
lower or limited tension in the transmission cable, which has
several advantages listed below. Also, lower tension in the jaw
closure transmission cable reduces jumpiness (lateral jerk due to
lateral movement of the high tension jaw closure transmission
cable) and S-bending (distortion of the joint due to buckling along
its center axis) in the output articulating joint.
[0026] This overall jaw closure transmission system may enable jaw
closure in two steps. During the first portion of the input stroke,
as the handle lever moves from its fully open position to an
approximately mid-way open position (typically about 30%-70% of the
stroke), the moving jaw goes from its fully open position to its
fully closed position. In this state, the jaw mechanism has
achieved its full output stroke and has reached a hard-stop. This
hard-stop may be the result of jaw on jaw contact, or the two jaws
holding a needle in between. In either case, the jaw mechanism has
reached a static state while there is still input stroke remaining
at the handle mechanism. From this point onwards, the remaining
stroke of the handle mechanism goes into axially stretching the
transmission member (i.e., cable) and/or axially compressing the
transmission guide members. The intentional axial compliance
selected in the transmission member and transmission guide member
(discussed above) enables the user to continue to displace the
handle lever through the remaining portion (i.e., the second
portion) of the handle mechanism's overall input stroke. During
this second portion of the input stroke, the actuation motion of
the handle shuttle causes the transmission member (e.g., cable) to
stretch and/or the transmission guide member (e.g., flexible
conduit) to compress, since the distal end of the transmission
member is static due to the static state of the jaw mechanism.
Thus, the second portion of the input stroke corresponds to
stretching the cable and an associated increase in tension of the
cable (based on the compliance of the cable). This gradually
increasing cable tension continues to serve as the input force on
the jaw mechanism and continues to get amplified by the mechanical
advantage of this mechanism (even though the mechanism itself is
static due to a hard-stop at the jaws). This means that the
clamping force between the jaws (with or without a needle in
between) keeps increasing as well. Thus, while the first portion of
the input stroke of the handle lever corresponds to an increasing
displacement of the moving jaw from a fully-open position to a
fully-closed position (i.e., total output stroke), which
corresponds to a hard-stop at the jaws (with or without a needle);
the second portion of the input stroke at the handle lever
corresponds to a gradually increasing clamping force between the
jaws (with or without a needle) at the EE assembly. The embodiment
may not only be a two-stage stroke, but also may be a three-stage
stroke wherein the third stage relates to a region dedicated to
facilitating handle lever locking. Within the third stage, the
handle lever angular displacement does not produce additional
transmission member displacement, and therefore does not introduce
any additional energy to the compliant transmission elements. The
primary purpose of the third stage is to provide a single region
where the handle mechanism locks into place. The presence of this
third stage provides an opportunity to optimize handle mechanism
design for locking, rather than for facilitating jaw mechanism
closure or clamp load generation. Specifically, the input force
required throughout the third stage does not depend on the
mechanical spring-rate property for the compliant transmission
members, but rather merely depends on frictional losses between the
members. As a result of isolating transmission sub-system and
output sub-system kinematic behavior from the third stage, users of
the device will experience a greater consistency of handle
mechanism input force. Furthermore, the user input force in the
third stage to lock the handle is significantly independent of
needle location within the jaws of the output mechanism.
[0027] This may result in several benefits for the user in the
design, including the substantial reduction in sudden step changes
in the force feedback felt by the surgeon at the handle lever as
needle contact or jaw contact happens. The presence of transmission
member and/or transmission guide member compliance in the axial
(i.e., transmission motion) direction makes this transition more
gradual and therefore better in feel for the user, compared to a
traditional device that has a highly rigid transmission member.
This may also result in a reduced number of transmission elements
since energy storage functionality is accomplished through the
dual-purpose cable and flexible guide members, which play a role in
actuation motion transmission as well as serve as energy storing
elastic elements. During the second portion of the input stroke of
the handle lever, the transmission sub-system efficiently stores
energy by means of stretching the transmission cable. This energy
storage is not passive, in the sense that the stretching of the
cable corresponds to an increase in cable tension, which, when
reflected through the mechanical advantage of the EE mechanism,
produces an increased jaw clamping force.
[0028] In general, the jaw closure transmission systems described
herein may be self-limiting and/or self-correcting and/or
self-regulating systems for limiting the maximum force that is
transmitted via the transmission member in spite of variations in
the presence and location of a an object (e.g., needle) in the
jaws. This may advantageously lower the loads of all
members/components of the jaw closure transmission system. This may
also or alternatively lead to less wear, longer life, less chances
of failure, more durability etc., and may eliminate the need for
complex input, transmission, and output force overload systems that
might require additional springs, linkages, and structural members.
In addition, these jaw closure transmission systems described
herein may regulate needle clamp load, which helps reduce damage to
needles, and/or may desensitize the system from a size and location
of a needle held between the jaws, and provide an adequate clamping
force without damaging the needle. These jaw closure transmission
systems may also regulate handle lever force applied by the surgeon
which is preferred from an ergonomic standpoint. In the case of a
rigid transmission member, it becomes very difficult for the
surgeon to regulate the clamping force at the jaws by adjusting his
input force/displacement at the handle lever. In such cases, a very
small change in the surgeon's input displacement at the handle
lever can produce a large, somewhat uncontrolled, change in the
clamping force. That is why, in such systems, there are discrete
ratchet points between the handle body and handle lever that allows
the surgeon to incrementally increase the clamping force at the
jaws in controlled amounts. The present jaw closure transmission
system, with the intentional use of compliance in the transmission
member and transmission guide members, provides the surgeon with a
much greater control of the clamping force at the jaws, thus
mitigating or eliminating the need for discrete ratchets at the
handle lever (with respect to handle body). Rather, this system
lets the surgeon rely upon his feel and discretion to regulate
input force to achieve a desired needle clamping force. This also
eliminates the need for complex multi-lock ratcheting mechanisms in
the handle assembly, which otherwise require an additional user
actuation component/input to disengage the locking mechanism,
without which the tool has to overload the needle or object in the
jaws to release it. The handle becomes simpler with a single lock
design, as it does not require an additional user input to
disengage the lock. Simplifying the handle reduces potential user
error and could result in less user training.
[0029] Also described herein are jaw closure transmission systems
in which an additional intermediate sub-system may be used. FIG. 3
illustrates one example of such a system, showing a handle
reference 301, handle mechanism 303, input lever/button 305, first
transmission member 307, first transmission guide 309, intermediate
transmission mechanism 311, second transmission guide 313, second
transmission member 315, and jaw mechanism 317. For example, in
addition to an input sub-system and an output sub-system, there may
also be an intermediate sub-system with an intermediate mechanism.
In that case there may be a first transmission member and
transmission guide member between the input and intermediate
sub-systems, and a second transmission member and transmission
guide member between the intermediate and output sub-systems. The
use of an axially compliant transmission and transmission guide
member may be preserved to achieve desired jaw closure
performance.
[0030] In any of the apparatuses described herein the handle input
may be a lever, or any other input allowing a variable degree of
actuation, and may generally be referred to herein as "levers",
including plungers, dials, knobs, etc.
[0031] As mentioned, these jaw closure transmission systems may
generally provide for connecting an input and an output comprising
rigid and compliant transmission elements, as well as rigid and
flexible transmission guiding elements, wherein the transmission
elements with finite flexibility in the transmission direction also
serve to store energy during closure transmission to achieve unique
and desirable functionality.
[0032] Thus, in a simple form, the system can be thought of as, but
not limited to, three sub-systems that are serially connected that
take an input, in the form of handle lever displacement by force
from the user, and produce an output that presents a moving jaw
displacement and clamp load.
[0033] The three sub-systems (input sub-system, which is referred
to as the handle mechanism; output sub-system, which is referred to
as the jaw mechanism; and transmission sub-system, which comprises
a transmission member, e.g., cable, and transmission guide, e.g.,
flexible conduit) may be represented in a system diagram as shown
in one example in FIG. 1. The example shown in FIG. 1 includes a
handle body or handle shell 101, a handle assembly 103 comprising a
handle mechanism having a handle lever 107 (input lever or input
link), a transmission guide 109 (rigid pulley) and/or flexible
conduit 109', a transmission cable 111, a return spring 113, a
fixed jaw 115 (end-effector base/reference) an end-effector
assembly 117 comprising a jaw mechanism including a drive pin 121,
a pulley pivot pin 123, a pulley 119, and a jaw pivot pin 125.
[0034] The input in a handle assembly may comprise a handle body or
shell that serves as the local reference or ground. The handle body
is generally designed to be ergonomic for the user to hold in
various positions since it is generally the articulation of the
handle body which controls the location and orientation of the
end-effector. Mechanically the handle body can be directly
connected to the end-effector via a tool shaft as in straight stick
laparoscopic instruments, serially, or connected to the
end-effector through an input articulating joint, a tool frame
(e.g., a frame, or a frame with a shaft extension, or a shaft),
and/or an output articulating joint having a series of joints which
provide articulation to the end-effector or even indirectly
attached to the end-effector, as described in U.S. Pat. No.
8,668,702. The handle body houses an internal mechanism (or handle
mechanism) consisting of a handle lever configured to receive user
input in the form of a displacement relative to the handle body.
Full handle lever displacement with respect to the handle body is
referred to as the input stroke. This input stroke is based on the
kinematic design of the handle mechanism and is limited by one or
more hard-stops in the handle mechanism. This input stroke is
designed to have a specific mechanical advantage curve profile
that, when combined with the other sub assembles, is unique to the
type of surgical instrument. Generally, for a surgical needle
driver, the mechanical advantage curve of the input sub-system
initially has a low mechanical advantage and then increases, to
have a high mechanical advantage at the end of the input stroke. At
full closure, i.e., the end of input stroke, the handle lever
reaches a hard-stop relative to the handle body. At this hard stop,
there may be a single locking or latching feature that keeps the
handle lever latched closed relative to the handle body. As
mentioned above, an unlatching/unlocking feature may unlock the
handle lever and allow it to open again with respect to the handle
body. The output of the handle mechanism is via the handle shuttle
(or output member, pull rod, or push rod), which interfaces with
the transmission member and provides an actuation motion to the
proximal end of the transmission member. The output of the handle
mechanism is not limited to a shuttle, the embodiment shown
consists of a "shuttle" because the handle mechanism is a 6 bar
linkage with a 1 DoF slider joint between the output member
(shuttle) and handle body. The handle mechanism is not limited to a
6 bar linkage. The handle mechanism could be a simple lever, 4 bar
linkage, cam slot, gear, etc. The handle mechanism may be
configured to provide a varying transmission ratio and mechanical
advantage between the handle lever and the handle shuttle, so as to
produce the appropriate actuation displacement and force at the
proximal end of the transmission member (i.e., appropriate cable
tension and cable displacement) via the handle shuttle during the
overall stroke of the handle lever (i.e., input stroke). The handle
mechanism itself may take the form of various configurations. As
opposed to a six-bar linkage as cited, in some variations, the
linkage system may be a 4-bar linkage, or any alternate system
containing a plurality of linkages or motion members that actuates
the transmission member either by rotary or linear motion.
Conversely, any of the linkages contained within the linkage system
could be driven by a cam that is purposefully designed to induce a
variable mechanical advantage throughout the handle's jaw closure
lever stroke. FIG. 13 shows an input sub-system consisting of a cam
(cam surface 1301 and cam transmission member 1305) which achieves
the desired variable mechanical advantage. FIG. 13 also shows a
shuttle 1307 connected to a shuttle actuation tension member 1309,
within the handle body 101. In some variations, the linkage system
may be a compliant mechanism that achieves the desired constant or
variable transmission ratio. This mechanism may lead to part count
reduction by still achieving similar performance. In some
variations, the handle mechanism is designed such that instead of
providing a constant mechanical advantage or transmission ratio, it
produce produces a higher transmission ratio (lower mechanical
advantage) in the first portion of the input stroke and a lower
transmission ratio (higher mechanical advantage) in the second
portion of the input stroke. While the mechanism for input into the
input sub-system generally includes an actuating lever body, or
ground reference, and a handle input lever, the input sub-system
may be embodied alternatively. The input sub-system may be embodied
as a motion member capable of translating mechanical energy
therein. For example, the input motion member may be a button,
dial, tension rod, or binary switch.
[0035] The output may generally be a jaw mechanism comprising a jaw
base (which may include or be integral) with a fixed jaw that
serves as the local reference or ground (alternatively two moving
jaws may be used), and the movable jaw may be coupled to the fixed
jaw (e.g., pivotally coupled to the fixed jaw) such that it can
open and close (i.e., displace) with respect the fixed jaw. The
structure of one end-effector (jaw assembly) embodiment is seen in
FIGS. 1, 2, 11, 12A, and 12B. As discussed above, the full closure
displacement of the end-effector moving jaw relative to the
end-effector fixed jaw is referred to as the output stroke. The
purpose of this closure displacement of the end-effector moving jaw
relative to the end-effector fixed jaw is to hold an object (such
as needle, suture, tissue, staple, clip etc.) between the jaws in
response to a corresponding closure displacement of the handle
lever relative to the handle body at the input of the closure
transmission system. The embodiment shown incorporates, but is not
limited to, a two-stage mechanical mechanism to produce the desired
mechanical advantage curve with the desired mechanical advantage
curve having a low mechanical advantage to start with and then
having a high mechanical advantage at the end. The design is not
limited to the current embodiment as long as the mechanical
advantage curve is conserved. In the embodiment shown, an
end-effector pulley coupled to the end-effector fixed jaw or the
fixed bearing member (e.g., pivotally coupled to the end-effector
fixed jaw) is configured to receive the actuation motion from the
distal end of the transmission member. A jaw mechanism (e.g.,
comprising a drive pin/cam surface) may translate the actuation
motion of the end-effector pulley relative to the fixed jaw to a
corresponding closure motion of the moving jaw relative to the
end-effector fixed jaw. In this example of the end-effector
mechanism, a drive pin is driven by the end-effector pulley and
interfaces with a camming surface on the moving jaw, providing a
camming action. Additionally, in this example of the end-effector
mechanism, the distal end of the transmission member (i.e., cable)
is wrapped around the end-effector pulley. To prevent a potential
slippage between the cable and the pulley, there may be a positive
engagement feature between the cable and the pulley. This may be
accomplished via a cylindrical member that is crimped onto the
cable and sits in a cavity on the pulley. Once the cable is wrapped
around the pulley, it is connected to a return spring either in the
jaw assembly, or on the transmission guide, or in the handle
assembly. The purpose of this return spring is to open the jaws
after full closure is reached and the handle lever returns to the
initial open angle. The end-effector mechanism is designed to
provide a varying transmission ratio and mechanical advantage
between the distal end of the transmission member and the
end-effector moving jaw so as to produce the appropriate output
displacement and force at the end-effector moving jaw relative to
the end-effector fixed jaw during the overall stroke of the
end-effector moving jaw (i.e., output stroke). This optimization is
based on the structure and functionality of the overall closure
transmission system including the input sub-system, transmission
sub-system, and output sub-system, and not just the output
sub-system. Specifically, the end-effector mechanism is designed to
provide a large mechanical advantage at the end of its stroke, to
maximally amplify the force in the transmission member (i.e.,
tension in the jaw closure transmission cable) to a clamping force
at the jaws. This implies that for a certain desired jaw clamping
force, if the mechanical advantage of the jaw mechanism is high
when the jaws are closed, the transmission cable tension can be
lower, which has several advantages. The end-effector may include
many different embodiments but is not limited to a pair of jaws,
useful for manipulation of needles, suture, tissue, cautery,
ligation clip application, etc.
[0036] The transmission sub-system may comprise the following
elements, a transmission member to transmit the closure action of
the input sub-system (i.e., handle assembly) to the output
sub-system (i.e., end-effector assembly) of the closure
transmission system. More specifically, the transmission member
transmits the actuation motion of the handle shuttle to a
corresponding actuation motion of the end-effector pulley. This
transmission member is a cable, braided rope, etc. that is capable
of accommodating very tight bends as might be necessary when the
closure transmission system is part of a remote access tool or
device as seen in FIGS. 1, 10, 15, and 16. The transmission member
is highly compliant (i.e., flexible) in bending, twisting, and
compression. This member is relatively stiffer in tension because
it has to transmit force and displacement along this direction; but
at the same time it is not chosen or designed to be infinitely or
effectively infinitely stiff. Rather, it is intentionally designed
or chosen to have a finite stiffness (or finite compliance) so that
it can also serve as an inline spring. The importance of this
finite stiffness for the system level performance is described
below. Note that nothing is infinitely stiff or infinitely
compliant. Infinite stiffness corresponds to zero compliance and
zero stiffness corresponds to infinite compliance. On some
normalized scale, a stiffness less than 10 is close to infinitely
compliant and a stiffness greater than 1000 is closely to
infinitely stiff. On such a scale, a stiffness in the range of
100-200 is where we might place the axial stiffness of the
transmission member.
[0037] A transmission guide may serve as a conduit or channel
(also, a reference) for the transmission member. A proximal portion
of this transmission guide is connected to the input sub-system
reference (i.e., handle body) and the distal portion of this
transmission guide is connected to the output sub-system reference
(i.e., end-effector fixed jaw). This guide may be completely rigid
in all directions such as a frame, or a shaft, or tube as seen in
FIG. 2. This guide may also be flexible in bending so that it can
take an arbitrary, tortuous shape but still remain very stiff
(ideally, close to infinitely stiffness) axially (i.e., along its
bent/deformed central axis). Additionally, this guide may be
flexible in bending so that it can take an arbitrary, tortuous
shape and have an intermediate stiffness (i.e., have some
intentionally finite compliance) in the axial direction (i.e.,
along its bent/deformed central axis). The connections between the
ends of the guide and respective references of the input and output
sub-systems may be close to infinitely stiff in the transmission
direction (i.e., axial direction of the transmission cable) or may
have some intentionally finite compliance (i.e., slightly lower
stiffness than infinitely stiff values). FIG. 2 shows a handle
assembly 202 comprising a handle mechanism including a handle lever
201 (input link or input lever), a cable 207, a handle body (or
handle reference) 203, a return spring 205, a transmission guide
member 209, a fixed jaw 211 (end-effector base or reference), an
end-effector assembly 213 comprising a jaw mechanism including a
pulley 215, a pulley pivot pin 217, a drive pin 219, and a jaw
pivot pin 223.
[0038] For example, described herein are medical devices having a
jaw assembly actuated by a transmission cable having a finite
stiffness in a transmission direction. For example the devices may
include: an elongate transmission guide, wherein the transmission
cable is routed through the transmission guide; a handle assembly
at a proximal end of the elongate transmission guide, the handle
assembly comprising a handle body, an input lever, a handle output
coupled to the transmission cable, and a handle mechanism coupling
the input lever to the handle output, wherein the handle mechanism
has an input stroke consisting of a full closure displacement of
the input lever relative to the handle body, further wherein the
input stroke is divided into a first part and a second part,
wherein the first part corresponds to a displacement of 30% to 70%
of the full closure displacement of the input lever and the second
part corresponds to the remaining displacement of the input lever;
and wherein the jaw assembly is distal to the elongate transmission
guide, the jaw assembly having a first jaw, a second jaw, a jaw
input coupled to the transmission cable, and a jaw mechanism
coupling the jaw input to the second jaw, wherein the jaw mechanism
has an open configuration when the first and second jaws are fully
open relative to each other and a closed configuration when the
first and second jaws are fully closed; further wherein the
displacement of the input lever relative to the handle body
corresponding to the first part of the input stroke actuates the
handle output which in turn actuates the jaw input via the
transmission cable, which in turn closes the first and second jaws
until the first and second jaws reach a hard stop, and thereafter
the displacement of the handle lever relative to the handle body
corresponding to the second part of the input stroke stretches the
transmission cable, wherein the resulting tension in the
transmission cable is converted by the jaw mechanism to a holding
force between the first and second jaws.
[0039] A medical device having a jaw assembly actuated by a
transmission cable having a finite stiffness in a transmission
direction may include: an elongate transmission guide comprising a
flexible conduit, wherein the transmission cable is routed through
the transmission guide; a handle assembly at a proximal end of the
elongate transmission guide, the handle assembly comprising a
handle body, an input lever, a handle output comprising a shuttle
coupled to the transmission cable, and a handle mechanism
comprising a six bar linkage coupling the input lever to the handle
output, wherein the handle mechanism has an input stroke consisting
of a full closure displacement of the input lever relative to the
handle body, further wherein the input stroke is divided into a
first part and a second part, wherein the first part corresponds to
a displacement of 30% to 70% of the full closure displacement of
the input lever and the second part corresponds to the remaining
displacement of the input lever; and wherein the jaw assembly is
distal to the elongate transmission guide, the jaw assembly having
a first jaw, a second jaw, a jaw input comprising a pulley coupled
to the transmission cable, and a jaw mechanism comprising a cam
surface between the jaw input and the second jaw, wherein the jaw
mechanism has an open configuration when the first and second jaws
are fully open relative to each other and a closed configuration
when the first and second jaws are fully closed; further wherein
the displacement of the input lever relative to the handle body
corresponding to the first part of the input stroke actuates the
handle output which in turn actuates the jaw input via the
transmission cable, which in turn closes the first and second jaws
until the first and second jaws reach a hard stop, and thereafter
the displacement of the handle lever relative to the handle body
corresponding to the second part of the input stroke stretches the
transmission cable, wherein the resulting tension in the
transmission cable is converted by the jaw mechanism to a holding
force between the first and second jaws.
[0040] The handle mechanism may be a linkage (e.g., six-bar
linkage, four-bar linkage, etc.) or a cam (cam surface and pin,
etc.). In general, the elongate transmission guide may comprise a
flexible conduit or elongate shaft or both.
[0041] The transmission cable may generally have a finite stiffness
in the direction of transmission (e.g., along the length of the
extended cable). For example the transmission cable may have a
stiffness in a transmission direction of less than 800 pounds per
inch, less than 700 pounds per inch, less than 650 pounds per inch,
less than 600 pounds per inch, less than 500 pounds per inch, less
than 400 pounds per inch, etc. (and in some variations be greater
than 100 pounds per inch, greater than 150 pounds per inch, greater
than 200 pounds per inch, greater than 250 pounds per inch, greater
than 300 pounds per inch, etc., e.g., between 100 and 650 pounds
per inch, etc.).
[0042] In any of these apparatuses (devices, systems, mechanism,
tools, etc.) the handle mechanism may be configured to provide a
first mechanical advantage during the first part of the input
stroke and a second mechanical advantage that is greater than the
first mechanical advantage during the second part of the input
stroke. The handle output may comprise one or more of: a shuttle, a
push rod, or a pull rod. The device may include a jaw base to which
either or both the first and second jaws are pivotally coupled.
[0043] The jaw input may comprise a jaw pulley, and the jaw
mechanism may comprise a cam surface between the jaw pulley and the
second jaw.
[0044] As mentioned above, any of these devices may include a
releasable latching mechanism configured to hold the handle lever
locked in a closed position at the end of the input stroke.
[0045] Also described herein are methods of using any of the
apparatuses including these jaw closure transmission systems. For
example, described herein are methods of operating a medical device
to close a jaw assembly of the medical device, wherein the medical
device comprises an elongate transmission guide, a finite stiffness
transmission cable within the transmission guide, and a handle
assembly at the proximal end of the elongate transmission guide
having an input lever and a handle mechanism coupling the input
lever to the transmission cable, wherein the transmission cable is
coupled to a jaw input of the jaw assembly, wherein the jaw
assembly is distal to the elongate transmission guide. The method
may include: actuating the input lever to apply tension to the
transmission cable during a first part of an input stroke of the
handle assembly to close a first and second jaw of the jaw assembly
from an open configuration until the first and second jaws reach a
hard stop; and continuing to actuate the input lever during a
second part of the input stroke after the first and second jaws
have reached the hard stop, and stretching the transmission cable;
wherein the input stroke consists of a full displacement of the
handle lever of the handle assembly, and further wherein the handle
assembly transitions from the first part of the input stroke to the
second part of the input stroke when the handle is between 30% and
70% displaced.
[0046] A method of operating a medical device to close a jaw
assembly of the medical device (wherein the medical device
comprises an elongate transmission guide, a finite stiffness
transmission cable within the transmission guide, and a handle
assembly at the proximal end of the elongate transmission guide
having an input lever and a handle mechanism coupling the input
lever to the transmission cable, wherein the transmission cable is
coupled to a jaw input of the jaw assembly, and wherein the jaw
assembly is distal to the elongate transmission guide) may include:
actuating the input lever to actuate the transmission cable during
a first part of an input stroke of the handle assembly and
translate the transmission cable relative to the elongate shaft to
close a first and second jaw of the jaw assembly from an open
configuration until the first and second jaws reach a hard stop;
and continuing to actuate the input lever and stretching the
transmission cable without translating the first or second jaws
during a second part of the input stroke after the first and second
jaws have reached the hard stop; wherein the input stroke consists
of a full displacement of the handle lever of the handle assembly,
and further wherein the handle assembly transitions from the first
part of the input stroke to the second part of the input stroke
when the handle is between 30% and 70% displaced.
[0047] Any of these methods may include applying a first mechanical
advantage during the first part of the input stroke and applying a
second mechanical advantage that is greater than the first
mechanical advantage during the second part of the input stroke.
These methods may also include grasping an object between the first
and second jaws, wherein the first and second jaws reach the hard
stop when the object is secured between the first and second
jaws.
[0048] Any of these methods may also include locking the input
lever in a fully closed position relative to a handle shell in the
handle assembly.
[0049] Any of these methods may also include releasing the input
lever to transition the handle lever from the second part of the
input stroke to the first part of the input stroke, reducing the
tension on the transmission cable and reducing the stretch of the
transmission cable before translating the transmission cable so
that the first and second jaws open. Actuating the input lever may
comprise squeezing the input lever.
[0050] As mentioned, these jaw closure transmission systems may be
integrated into any appropriate apparatus. For example, any of
these apparatus may be configured as a medical device, see for
example FIGS. 15 and 16, including a jaw closure transmission
system. For example, a medical device having a distal jaw assembly
actuated by a transmission cable having a finite stiffness in the
transmission direction and that is compliant in bending may
include: a tool frame comprising an elongate shaft and a forearm
attachment region at a proximal end of the tool frame configured to
couple with an arm attachment cuff; a handle assembly, the handle
assembly comprising a handle shell configured to be gripped in a
user's palm and an input lever on the handle shell, wherein the
handle shell encloses a handle linkage coupling the input lever to
the transmission cable through a handle output, further wherein the
handle assembly has an input stroke consisting of a full closure
displacement of the input lever from an undisplaced configuration
to a fully displaced configuration, further wherein the input lever
transitions from a first part of the input stroke to a second part
of the input stroke when the input lever is displaced from an
undisplaced configuration to between 30% and 70% of its full
closure displacement configuration; an input joint between the
handle and the tool frame configured to encode motion of the handle
about a pitch axis of rotation relative to the tool frame for
transmission to an articulating output joint, and further
configured to encode motion of the handle about a yaw axis of
rotation relative to the tool frame for transmission to the
articulating output joint, wherein the pitch axis of rotation and
the yaw axis of rotation intersect in a center of rotation; wherein
the jaw assembly is coupled to the distal end of the elongate tool
shaft by the articulating output joint, the jaw assembly having a
first jaw, a jaw pulley pivotally coupled to the first jaw and
further coupled to the transmission cable, a second jaw pivotally
coupled to the first jaw, and a cam surface that translates motion
of the jaw pulley to a motion of the second jaw relative to the
first jaw, wherein the jaw assembly has an output stroke that
extends from an open configuration when the first and second jaws
are fully open to a closed configuration when the first and second
jaws are fully closed; wherein the displacement of the input lever
relative to the handle body corresponding to the first part of the
input stroke actuates the handle output which in turn actuates the
jaw input via the transmission cable, which in turn closes the
first and second jaws until the first and second jaws reach a hard
stop, and thereafter the displacement of the handle lever relative
to the handle body corresponding to the second part of the input
stroke stretches the transmission cable, wherein the resulting
tension in the transmission cable is converted by the jaw mechanism
to a holding force between the first and second jaws; and a
transmission guide extending between the handle assembly and the
elongate shaft, wherein the transmission cable extends from the
handle assembly, through the transmission guide to the jaw
assembly. FIGS. 10, 14, 15 and 16 illustrate one example of such an
apparatus.
[0051] In FIG. 10, a medical device apparatus includes a jaw
closure transmission as described above. The exemplary apparatus
includes a tool frame 525, which includes a tool shaft 526 and a
forearm attachment portion at the proximal end 527. A cuff (not
shown) having a passage therethrough that is configured to hold a
wrist or forearm of a user may be coupled to the forearm attachment
portion, in some variations via a bearing between the forearm
attachment portion of the frame and the cuff that is configured to
slide or roll so that there is a roll rotational degree of freedom
between the frame and the cuff about the tool axis. A proximal
handle assembly may be connected to the tool frame by an input
joint. The input joint may be configured to encode motion between
the tool frame and the handle assembly, as shown in FIG. 10. In
this example, the input joint includes a pair of transmission
strips 533, 534 that connect to respective pivoting joints (not
shown) in parallel to separately encode pitch and yaw rotations of
the handle assembly. The output joint 583 (an end-effector
articulation joint configured as a jaw assembly), as shown in FIG.
14, may be any of the multi-cluster joints described herein and is
between the jaw assembly and the tool frame (e.g., tool shaft) and
receives transmission input (e.g., cables, not shown) from the
output joint (including transmission strips 533, 534 of the output
joint) to articulate the jaw assembly.
[0052] In this example, the handle assembly includes an ergonomic
palm grip portion 501 (handle shell) that connects to the rotation
dial 502. The handle assembly also includes a control (lever) 549
input (in this example, defining the end-effector jaw closure
input) that is configured as a handle lever and acts as a rigid
extension of the internal push rod. A transmission cable 566
connects to the shuttle and acts as a jaw closure actuation
transmission member extending from the shuttle and through the tool
shaft 526 to the jaw assembly. This transmission cable may be
enclosed by a protective and/or supporting sheath or cover or
conduit, for some or the entire portion of its length. The
end-effector is a jaw assembly including a first (ground)
end-effector portion, in this example, including a fixed jaw 569 to
which a pivoting second end-effector portion (moving jaw 568) is
attached. The transmission cable 566 may couple to the moving jaw
568 at the end-effector closure output 577.
[0053] In FIG. 10, rotation of the dial portion 502 of the handle
assembly when the user's forearm is mounted to the proximal end and
the palm grip region 501 is held in the user's hand so that the
user can rotate the dial between the thumb and fingers, rotates the
entire tool frame, and therefore the end-effector that is attached
to the distal end of the tool shaft 526 via an end-effector output
articulating joint 583. Thus, the handle may rotate about first
axis 511, referred to as the handle articulated roll axis (axis 1),
to cause the tool shaft to rotate in a third axis 515, referred to
as the tool shaft roll axis (axis 3), in turn causing the
end-effector to roll about a second axis 513, referred to as an
end-effector articulated roll axis (axis 2).
[0054] The rotation dial 502 as shown in FIG. 10 is rotated about
the first axis 511. The rotation leads to rotation of tool frame
525 via transmission strips 533, 534 (as they constrain rotation
DoF), rotation of the tool shaft 526 (about the third axis 515),
and therefore, the rotation of the end-effector (about the second
axis 513). When the handle is articulated using the input
articulating joint, the output joint (multi-cluster joint 583) and
the end-effector articulate via the output articulating joint 583.
The center axis (axis 2) 513 for the end-effector is different from
the axis 3, the shaft axis 515. The intermediate transmission
mechanism consists of but is not limited to a cam mechanism as seen
in FIG. 3B. The intermediate transmission mechanism could be a
linkage, gear, cog etc. During stroke A, the force is not being
amplified through the intermediate transmission mechanism, however
at the transition from stroke A to stroke B the first transmission
member lifts off the hub 353 and rides a surface farther away from
the cam's center of rotation, creating a force amplification from
the first transmission member to the second transmission member.
This force amplification increases the mechanical advantage of the
system. This mechanism is shown in the structure of the device in
FIG. 3C (e.g., including transmission cam 361, transmission members
362, return pulley 363 and return spring 364). While this
transmission system invention is specifically embodied as a
laparoscopic, endoscopic, or other minimally invasive surgical jaw
closure device, it is understood that those skilled in the art can
alternately translate the invention, without departing from the
scope, to alternate embodiments for transmission systems such as
those that require end-effector clamping action like grasping,
holding, or clamping instruments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] The novel features of the invention are set forth with
particularity in the claims that follow. A better understanding of
the features and advantages of the present invention will be
obtained by reference to the following detailed description that
sets forth illustrative embodiments, in which the principles of the
invention are utilized, and the accompanying drawings of which:
[0056] FIG. 1 shows an example of a system diagram of a jaw closure
transmission system consisting of an input sub-system, a flexible
transmission sub-system and an output sub-system.
[0057] FIG. 2 is another diagram showing an example of a jaw
closure transmission system consisting of an input sub-system, a
rigid transmission sub-system and an output sub-system.
[0058] FIG. 3 is another diagram showing an example of a jaw
closure transmission system with an intermediate transmission
mechanism incorporated into the jaw closure transmission system.
FIG. 3B shows an embodiment of an intermediate transmission cam
used to create a force amplification from the first transmission
member 351 to the second transmission member 352. FIG. 3C shows an
embodiment of an intermediate transmission mechanism located inside
a device/tool.
[0059] FIG. 4 shows various cross-sections for needles that are
commonly used in minimally invasive surgery and that may be grasped
by an apparatus including any of the jaw closure transmission
systems described herein.
[0060] FIG. 5 illustrates various needle sizes that are commonly
used in minimally invasive surgery.
[0061] FIG. 6 shows various needle geometries that are commonly
used in minimally invasive surgery.
[0062] FIG. 7 is a front view of needle driver jaws clamping down
on a curved needle.
[0063] FIG. 8 shows graphs illustrating the transmission system of
a needle driver's input stroke.
[0064] FIG. 9 shows a mechanical advantage profile for the entire
system as a function of the input handle lever displacement.
[0065] FIG. 10 illustrates one example of a medical device
incorporating a jaw closure transmission system as described
herein.
[0066] FIG. 11 shows an exploded view of an end-effector assembly.
In FIG. 11, the end-effector assembly may include a movable jaw
1101 (having an engagement surface 1102, jaw pivot 1103, clearance
slot 1104, and drive slot 1105), a pulley 1103 (having a drive pin
110) that connects to a cable 1109, and a fixed jaw 1111 (having an
engagement surface 1112, pulley pivot pin 1114, and movable jaw
pivot pin 1113).
[0067] FIG. 12A shows a detailed view of an end-effector assembly
where the moveable jaw is in open condition.
[0068] FIG. 12B shows a detailed view of an end-effector assembly
where the moveable jaw is grasping a needle.
[0069] FIG. 13 shows an input sub-system comprising a cam in the
handle mechanism.
[0070] FIG. 14 shows an embodiment of an end-effector assembly
including an output articulation joint (including gimbals 1403,
1403', 1403'', gimbal guides 1406, articulation cables 1404, 1404',
and bottom gimbal guide 1405) and including an end-effector 1401,
articulation cable termination 1402, and tool shaft 1407.
[0071] FIG. 15 shows an embodiment of a minimally invasive surgical
device that incorporates a jaw closure transmission system as
described here. The device includes end-effector jaws 1501,
endeffector articulating joint 1502, tool shaft 1503, tool frame
1504 (including outer ring 1505), wrist cuff 1506, forearm attach
joint 1507, handle 1508, handle dial 1511, transmission strip(s)
1509, tool input joint 1510 and flexible conduit 1512.
[0072] FIG. 16 shows an embodiment of a minimally invasive surgical
device that incorporates a jaw closure transmission system as
described here.
DETAILED DESCRIPTION
[0073] Described herein are jaw closure transmission systems and
apparatuses including them. For example, described herein are
transmission systems (jaw closure transmission systems) for a
remote access tool which incorporates a transmission member with
finite transmission direction stiffness (or equivalently, a
compliant transmission member) that interfaces with the input and
output mechanisms of the remote access tool. A relatively stiff
transmission member of known use in medical devices can't be
replaced with a compliant transmission member to achieve the
performance described herein. The transmission system in its
entirety must be designed in unison to achieve the performance that
will be described. The performance of the transmission system in
its current configuration is specific for a needle driver. Surgical
needle drivers are typically one handed operation devices which
require high clamping loads at jaw clamping surfaces in order to
drive various needles through tissues. It is important to
understand the various types of needles because the design of a
compliant transmission member can protect the needle from damage
when overdriving the jaws. FIG. 4 shows various needle types that
are selected based on the medium that they are driven through. The
body of the needle is just as important as the tip, in that, as the
needle is driven through the tissue, there is an interaction
between the needle in its entirety and the tissue. The jaws of a
needle driver are designed with a pattern intended to increase the
needle retention without requiring high jaw clamping loads.
However, if a large enough clamping load is applied to the needle,
the clamping surfaces will damage the needle body, leaving
permanent impressions on the needle surface. When the surface of
the needle is damaged, it will no longer slide smoothly through the
tissues, which will result in resistance felt by the surgeon and
unnecessary damage to the patient.
[0074] In addition to surface damage on the needle, an overload in
clamping force could cause the shape of the needle to permanently
deform. Needles used for minimally invasive surgery also come in
various shapes and sizes, as seen in FIG. 5 and FIG. 6
respectively. The jaws of the needle driver are designed to be wide
enough to not allow the needle to rotate; as a result, needles with
a larger curve and smaller diameter can be easily deformed and
straighten out by large clamping loads. FIG. 7 showed a curved
needle being held by the upper and lower jaws of a needle driver;
as a larger clamping load is applied, the needle would straighten
in that region due to three-point bending, causing the needle to
not drive through the tissue in a true arc.
[0075] The needle location in the jaws also influences the
corresponding jaw clamping force and impacts its ability to
adequately secure a needle. The needle can be placed anywhere along
the jaw length which could mean at the very tip of the jaws or at
the mouth of the jaws; this significantly changes the effort
required by the user to actuate the input mechanism completely to
full stroke. In some configurations full stroke should not be
achieved due to potential damage to the needle, therefore typical
needle drivers incorporate an input ratcheting system, where the
stroke of the handle can be broken up into finite segments in
between ratchets to allow the user to hold the needle at various
input lever locations.
[0076] The use of a compliant transmission member solves these
problems and eliminates the discrepancy among uses users in the
amount of input used to adequately hold the needle. A compliant
transmission member acts as an energy storage member so that the
user can actuate the input handle lever completely without having
to worry about over-driving the jaws and damaging the needle. If a
large needle is placed within the mouth of the jaws, a full stroke
can still be achieved at the handle input lever while in a needle
driver with a stiff transmission member, full stroke would not be
achievable without causing damage to the instrument or the needle.
This reduces the need for a multiple ratchet system which can
provide discrepancies to users on whether adequate jaw clamping
force is achieved. The handle lever displacement (input stroke) can
be broken up into two different phases, stoke A and stoke B.
Whereas the transition from stoke A to stoke B occurs when the jaws
reach a hard stop, such that stoke A is before jaw hard stop and
stoke B is after the jaw hard stop. Jaw hard stop could occur at
various handle lever displacements depending on the needle type,
needle location or even needle presence. FIG. 8 shows various
graphs that help explain what happens in the system as a fully
input stroke is achieved.
[0077] FIG. 8 graph 1 shows the handle output; the profile of this
curve is achieved through the geometry of the handle mechanism.
This graph indirectly shows the mechanical advantage and the
transmission ratio of the handle mechanism. This profile is
extremely important as it is a non-constant mechanical advantage
which consists of a low mechanical advantage at the beginning of
the input stroke and then increases the mechanical advantage
towards the end of the stroke. Due to ergonomic reasons (or
limits), the limit of input displacement and force at the handle
varies throughout the lever stroke (through the range of angular
displacement). A varying mechanical advantage in the system means
that stroke A can have a completely different transmission ratio
than in stroke B. During stroke A, the jaws are freely rotating in
space, and therefore a high transmission ratio and low mechanical
advantage can be implemented into the design during this phase
which enables the jaws to achieve a wide opening angle. While in
stroke B, when the jaws reach a hard stop, a higher mechanical
advantage is desired such that a large clamping load at the output
can ergonomically be applied from the input. The system
transmission ratio comes from two sources, the handle mechanism and
the jaw mechanism. The jaw mechanism which is seen in FIG. 8 graph
2, has a similar mechanical advantage and transmission ratio curve
as the handle mechanism, a low mechanical advantage to start, and
then a high mechanical advantage to end the stroke. However, the
jaw mechanism has a different stroke than the input mechanism. The
entirety of the jaw mechanism stroke is contained within stroke A,
because the transition between stroke A and stroke B happens when
the jaws reach a hard stop and the mechanism thereon remains fixed
providing a constant mechanical advantage for the rest of the input
stroke. The profile of the system's net mechanical advantage curve
is seen in FIG. 9. This profile allows the user to apply a large
clamping load with very little effort at the handle while still
achieving a large jaw opening angle.
[0078] Graph 3 in FIG. 8 shows the performance of the compliant
transmission member (cable). Since there is no force build up in
stroke A, the cable does not stretch; however in stroke B, the
cable is stretched because the jaw mechanism is fixed at the distal
end while the input handle mechanism is still able to produce more
cable displacement as the handle input lever reaches a full
displacement (full stroke). A system with a much stiffer
transmission member, such a steel rod or a flexible control wire,
will not perform in this manner, as displacement at the input
handle would be really hard to generate because the forces would
directly relate to the clamping forces on the needle. A compliant
transmission member allows for a soft buildup of force at the
handle over a displacement to generate the closure force required.
Cable tension is shown in graph 4. During stroke A the force felt
at the handle input is the handle return spring which is shown in
FIG. 8 to have a linear spring constant, K. As the stroke
transitions to stroke B, the handle force is now the sum of the
handle return spring and then tension in the cable, the more
compliant the transmission member the less drastic the increase of
input force is at the stroke A to B transition. As shown in graph
5, as the handle input lever achieves full stroke, the needle
clamping force increases greatly based on the compliance of the
cable and the amount of handle lever displacement left in stroke B.
A transmission member that is too compliant would mean inadequate
clamping load while a transmission member that is too stiff would
require a ratcheting system and could damage the needle. As shown
in graph 6 of FIG. 8, even as the needle clamping force increases,
the handle lever input force doesn't increase as much due to the
increasing high mechanical advantage of the handle mechanism and
the fixed mechanical advantage of the jaw mechanism. This gradual
increase in handle force while achieving optimal jaw closure
eliminates the need of the multiple ratchet system that is required
on needle drivers with a really stiff transmission member.
[0079] When a feature or element is herein referred to as being
"on" another feature or element, it can be directly on the other
feature or element or intervening features and/or elements may also
be present. In contrast, when a feature or element is referred to
as being "directly on" another feature or element, there are no
intervening features or elements present. It will also be
understood that, when a feature or element is referred to as being
"connected", "attached" or "coupled" to another feature or element,
it can be directly connected, attached or coupled to the other
feature or element or intervening features or elements may be
present. In contrast, when a feature or element is referred to as
being "directly connected", "directly attached" or "directly
coupled" to another feature or element, there are no intervening
features or elements present. Although described or shown with
respect to one embodiment, the features and elements so described
or shown can apply to other embodiments. It will also be
appreciated by those of skill in the art that references to a
structure or feature that is disposed "adjacent" another feature
may have portions that overlap or underlie the adjacent
feature.
[0080] Terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. For example, as used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when
used in this specification, specify the presence of stated
features, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, steps, operations, elements, components, and/or groups
thereof. As used herein, the term "and/or" includes any and all
combinations of one or more of the associated listed items and may
be abbreviated as "/".
[0081] Spatially relative terms, such as "under", "below", "lower",
"over", "upper" and the like, may be used herein for ease of
description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if a device in the figures is inverted, elements
described as "under" or "beneath" other elements or features would
then be oriented "over" the other elements or features. Thus, the
exemplary term "under" can encompass both an orientation of over
and under. The device may be otherwise oriented (rotated 90 degrees
or at other orientations) and the spatially relative descriptors
used herein interpreted accordingly. Similarly, the terms
"upwardly", "downwardly", "vertical", "horizontal" and the like are
used herein for the purpose of explanation only unless specifically
indicated otherwise.
[0082] Although the terms "first" and "second" may be used herein
to describe various features/elements (including steps), these
features/elements should not be limited by these terms, unless the
context indicates otherwise. These terms may be used to distinguish
one feature/element from another feature/element. Thus, a first
feature/element discussed below could be termed a second
feature/element, and similarly, a second feature/element discussed
below could be termed a first feature/element without departing
from the teachings of the present invention.
[0083] Throughout this specification and the claims which follow,
unless the context requires otherwise, the word "comprise", and
variations such as "comprises" and "comprising" means various
components can be conjointly employed in the methods and articles
(e.g., compositions and apparatuses including device and methods).
For example, the term "comprising" will be understood to imply the
inclusion of any stated elements or steps but not the exclusion of
any other elements or steps.
[0084] In general, any of the apparatuses and methods described
herein should be understood to be inclusive, but all or a subset of
the components and/or steps may alternatively be exclusive, and may
be expressed as "consisting of" or alternatively "consisting
essentially of" the various components, steps, sub-components or
sub-steps.
[0085] As used herein in the specification and claims, including as
used in the examples and unless otherwise expressly specified, all
numbers may be read as if prefaced by the word "about" or
"approximately," even if the term does not expressly appear. The
phrase "about" or "approximately" may be used when describing
magnitude and/or position to indicate that the value and/or
position described is within a reasonable expected range of values
and/or positions. For example, a numeric value may have a value
that is +/-0.1% of the stated value (or range of values), +/-1% of
the stated value (or range of values), +/-2% of the stated value
(or range of values), +/-5% of the stated value (or range of
values), +/-10% of the stated value (or range of values), etc. Any
numerical values given herein should also be understood to include
about or approximately that value, unless the context indicates
otherwise. For example, if the value "10" is disclosed, then "about
10" is also disclosed. Any numerical range recited herein is
intended to include all sub-ranges subsumed therein. It is also
understood that when a value is disclosed that "less than or equal
to" the value, "greater than or equal to the value" and possible
ranges between values are also disclosed, as appropriately
understood by the skilled artisan. For example, if the value "X" is
disclosed the "less than or equal to X" as well as "greater than or
equal to X" (e.g., where X is a numerical value) is also disclosed.
It is also understood that the throughout the application, data is
provided in a number of different formats, and that this data,
represents endpoints and starting points, and ranges for any
combination of the data points. For example, if a particular data
point "10" and a particular data point "15" are disclosed, it is
understood that greater than, greater than or equal to, less than,
less than or equal to, and equal to 10 and 15 are considered
disclosed as well as between 10 and 15. It is also understood that
each unit between two particular units are also disclosed. For
example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are
also disclosed.
[0086] Although various illustrative embodiments are described
above, any of a number of changes may be made to various
embodiments without departing from the scope of the invention as
described by the claims. For example, the order in which various
described method steps are performed may often be changed in
alternative embodiments, and in other alternative embodiments one
or more method steps may be skipped altogether. Optional features
of various device and system embodiments may be included in some
embodiments and not in others. Therefore, the foregoing description
is provided primarily for exemplary purposes and should not be
interpreted to limit the scope of the invention as it is set forth
in the claims.
[0087] The examples and illustrations included herein show, by way
of illustration and not of limitation, specific embodiments in
which the subject matter may be practiced. As mentioned, other
embodiments may be utilized and derived therefrom, such that
structural and logical substitutions and changes may be made
without departing from the scope of this disclosure. Such
embodiments of the inventive subject matter may be referred to
herein individually or collectively by the term "invention" merely
for convenience and without intending to voluntarily limit the
scope of this application to any single invention or inventive
concept, if more than one is, in fact, disclosed. Thus, although
specific embodiments have been illustrated and described herein,
any arrangement calculated to achieve the same purpose may be
substituted for the specific embodiments shown. This disclosure is
intended to cover any and all adaptations or variations of various
embodiments. Combinations of the above embodiments, and other
embodiments not specifically described herein, will be apparent to
those of skill in the art upon reviewing the above description.
* * * * *