U.S. patent application number 12/618549 was filed with the patent office on 2011-03-24 for curved cannula.
This patent application is currently assigned to Intuitive Surgical, Inc.. Invention is credited to Samuel Au, Craig R. Gerbi, Giuseppe Maria Prisco, Theodore W. Rogers, John Ryan Steger, Charles E. Swinehart.
Application Number | 20110071541 12/618549 |
Document ID | / |
Family ID | 43014404 |
Filed Date | 2011-03-24 |
United States Patent
Application |
20110071541 |
Kind Code |
A1 |
Prisco; Giuseppe Maria ; et
al. |
March 24, 2011 |
CURVED CANNULA
Abstract
A robotic surgical system is configured with rigid, curved
cannulas that extend through the same opening into a patient's
body. Surgical instruments with passively flexible shafts extend
through the curved cannulas. The cannulas are oriented to direct
the instruments towards a surgical site. Various port features that
support the curved cannulas within the single opening are
disclosed. Cannula support fixtures that support the cannulas
during insertion into the single opening and mounting to robotic
manipulators are disclosed. A teleoperation control system that
moves the curved cannulas and their associated instruments in a
manner that allows a surgeon to experience intuitive control is
disclosed.
Inventors: |
Prisco; Giuseppe Maria;
(Mountain View, CA) ; Au; Samuel; (Sunnyvale,
CA) ; Gerbi; Craig R.; (Half Moon Bay, CA) ;
Rogers; Theodore W.; (Alameda, CA) ; Steger; John
Ryan; (Sunnyvale, CA) ; Swinehart; Charles E.;
(San Jose, CA) |
Assignee: |
Intuitive Surgical, Inc.
Sunnyvale
CA
|
Family ID: |
43014404 |
Appl. No.: |
12/618549 |
Filed: |
November 13, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61245171 |
Sep 23, 2009 |
|
|
|
Current U.S.
Class: |
606/130 |
Current CPC
Class: |
A61B 2017/3466 20130101;
Y10S 901/41 20130101; A61B 17/3474 20130101; A61B 50/13 20160201;
A61B 2017/3447 20130101; A61B 90/90 20160201; A61B 2034/301
20160201; A61B 2017/2936 20130101; A61B 2017/3429 20130101; A61B
34/71 20160201; A61B 34/73 20160201; A61B 17/3439 20130101; A61B
17/3431 20130101; A61B 2017/00845 20130101; A61B 2017/2904
20130101; A61B 2017/2905 20130101; A61B 2017/3454 20130101; A61B
2090/0811 20160201; A61B 2017/00526 20130101; A61B 2017/2929
20130101; A61B 34/76 20160201; A61B 2017/3419 20130101; A61B
17/3421 20130101; A61B 17/3423 20130101; A61B 34/70 20160201; A61B
34/30 20160201; A61B 90/50 20160201; A61B 2017/3441 20130101; A61B
2034/305 20160201; A61B 34/37 20160201; A61B 2017/00477 20130101;
A61B 90/92 20160201; A61B 1/00149 20130101; A61B 2017/3445
20130101 |
Class at
Publication: |
606/130 |
International
Class: |
A61B 19/00 20060101
A61B019/00 |
Claims
1. A surgical system comprising: a first robotic manipulator, a
first curved cannula coupled to the first robotic manipulator, and
a first surgical instrument comprising a flexible shaft that
extends through the first curved cannula, wherein the first robotic
manipulator is configured to move the first cannula around a first
center of motion; a second robotic manipulator, a second curved
cannula coupled to the second robotic manipulator, and a second
surgical instrument comprising a flexible shaft that extends
through the second curved cannula, wherein the second robotic
manipulator is configured to move the second cannula around a
second center of motion; wherein the first and second centers of
motion are positioned proximate to one another; and wherein distal
ends of the first and second curved cannulas are oriented to direct
the distal ends of the first and second surgical instruments
towards a surgical site.
2. The surgical system of claim 1: wherein the first curved cannula
comprises a rigid tube having a proximal straight portion and a
curved section adjacent the proximal straight section; and wherein
the first robotic manipulator is coupled to the proximal straight
portion of the first curved cannula.
3. The surgical system of claim 1: wherein the flexible shaft of
the first surgical instrument comprises a passively flexible shaft;
wherein the passively flexible shaft comprises a middle section and
a distal section; and wherein a stiffness of the distal second of
the passively flexible shaft is larger than a stiffness of the
middle section of the passively flexible shaft.
4. The surgical system of claim 1 further comprising: a port
feature; wherein the port feature comprises a port feature body
comprising a top surface and a bottom surface; wherein the port
feature comprises a first channel through which the first surgical
instrument extends in a first direction towards a vertical
midsection of the port feature body from the top surface to the
bottom surface; and wherein the port feature comprises a second
channel through which the second surgical instrument extends in a
second direction, opposite the first direction; towards the
vertical midsection of the port feature body from the top surface
to the bottom surface.
5. The surgical system of claim 1 further comprising: a port
feature; wherein the port feature comprises a funnel portion, a
tongue, a waist portion between the funnel portion and the tongue,
a first instrument channel defined in the waist portion through
which the first surgical instrument extends, and a second
instrument channel defined in the waist portion through which the
second surgical instrument extends.
6. The surgical system of claim 1 further comprising: a cannula
mounting fixture; wherein the cannula mounting fixture comprises an
endoscope cannula mounting bracket and a curved cannula mounting
bracket; and wherein the endoscope cannula mounting bracket and the
curved cannula mounting bracket are each oriented to hold a cannula
at the same opening into a patient's body.
7. The surgical system of claim 1 further comprising: a pointed cap
comprising an interior; wherein the interior of the cap is
configured to removably hold a distal end of an endoscope and a
distal end of the first curved cannula.
8. The surgical system of claim 1 further comprising: a master
manipulator; and a control system; wherein a straight line
instrument insertion and withdrawal axis is defined extending from
a longitudinal center axis of the first curved cannula at a distal
end of the first curved cannula; and wherein in response to a
movement of the master manipulator, the control system commands the
first robotic manipulator to move the distal end of the first
curved cannula around the first remote center of motion as if the
first surgical instrument were positioned straight along the
instrument insertion and withdrawal axis.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of provisional U.S.
Patent Application No. 61/245,171 (filed Sep. 23, 2009) (disclosing
"Curved Cannula"), which is incorporated herein by reference.
BACKGROUND
[0002] 1. Field of Invention
[0003] Inventive aspects pertain to minimally invasive surgery,
more particularly to minimally invasive robotic surgical systems,
and still more particularly to minimally invasive robotic surgical
systems that work through a single entry point into the patient's
body.
[0004] 2. Art
[0005] Benefits of minimally invasive surgery are well known, and
they include less patient trauma, less blood loss, and faster
recovery times when compared to traditional, open incision surgery.
In addition, the use of robotic surgical systems (e.g.,
teleoperated robotic systems that provide telepresence), such as
the da Vinci.RTM. Surgical System manufactured by Intuitive
Surgical, Inc. of Sunnyvale, Calif. is known. Such robotic surgical
systems may allow a surgeon to operate with intuitive control and
increased precision when compared to manual minimally invasive
surgeries.
[0006] To further reduce patient trauma and to retain the benefits
of robotic surgical systems, surgeons have begun to carry out a
surgical procedure to investigate or treat a patient's condition
through a single incision through the skin. In some instances, such
"single port access" surgeries have been performed with manual
instruments or with existing surgical robotic systems. What is
desired, therefore, are improved equipment and methods that enable
surgeons to more effectively perform single port access surgeries,
as compared with the use of existing equipment and methods. It is
also desired to be able to easily modify existing robotic surgical
systems that are typically used for multiple incision (multi-port)
surgeries to perform such single port access surgeries.
SUMMARY
[0007] In one aspect, a surgical system includes a robotic
manipulator, a curved cannula, and an instrument with a passively
flexible shaft that extends through the curved cannula. The robotic
manipulator moves the curved cannula around a remote center of
motion that is placed at an opening into a patient's body (e.g., an
incision, a natural orifice) so that the curved cannula provides a
triangulation angle for the surgical instrument at the surgical
site. In one implementation, an endoscope and two such curved
cannulas with distal ends oriented towards a surgical site from
different angles are used so that effective instrument
triangulation is achieved, which allows the surgeon to effectively
work at and view the surgical site.
[0008] In another aspect, the curved cannula includes a straight
section and an adjacent curved section. A robotic manipulator
mounting bracket is coupled to the straight section. A second
straight section may be coupled to the opposite end of the curved
section to facilitate alignment of a passively flexible surgical
instrument that extends out of the cannula's distal end towards a
surgical site.
[0009] In another aspect, a surgical instrument includes a
passively flexible shaft and a surgical end effector coupled to the
distal end of the shaft. The flexible shaft extends through a
curved cannula, and a distal section of the flexible shaft extends
cantilevered beyond a distal end of the curved cannula. The distal
section of the flexible shaft is sufficiently stiff to provide
effective surgical action at the surgical site, yet it is
sufficiently flexible to allow it to be inserted and withdrawn
through the curved cannula. In some aspects, the stiffness of the
distal section of the instrument shaft is larger than the stiffness
of the section of the shaft that remains in the curved section of
the cannula during a surgical procedure.
[0010] In another aspect, a surgical port feature is a single body
that includes channels between its top and bottom surfaces. The
channels are angled in opposite directions to hold the straight
sections of the curved cannulas at a desired angle. The body is
sufficiently flexible to allow the curved cannulas to move around
remote centers of motion that are generally located within the
channels. In some aspects the port feature also includes a channel
for an endoscope cannula and/or one or more auxiliary channels. The
channels may include various seals.
[0011] In another aspect, a second port feature that includes an
upper funnel portion and a lower tongue is disclosed. Channels for
surgical instruments, such as the curved cannulas, are defined in a
waist section that joins the funnel portion and the tongue. In one
aspect, this second port feature is used for surgeries that require
instruments to enter the patient's body at a relatively small
(acute) angle, because the port feature helps prevent unnecessary
stress between the instruments and the patient's body and vice
versa.
[0012] In another aspect, cannula mounting fixtures are disclosed.
These fixtures support the cannulas for insertion and for docking
to their associated robotic manipulators. In one aspect, a fixture
includes arms that hold an endoscope cannula and a curved
instrument cannula. In another aspect, a fixture is configured as a
cap that holds distal ends of an endoscope and a curved cannula.
The cap is pointed to facilitate insertion into the opening into
the patient.
[0013] In another aspect, a control system for a robotic surgical
system with a curved cannula is disclosed. The control system uses
kinematic data associated with the curved cannula. To provide an
intuitive control experience for the surgeon, the control system
commands a robotic manipulator to move the curved cannula and its
instrument in response to the surgeon's inputs at a master
manipulator as if the instrument were positioned along a straight
axis that extends from the distal end of the curved cannula,
generally tangent to the distal end of the cannula's curved
section.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1A is a front elevation view of a patient side cart in
a robotic surgical system.
[0015] FIG. 1B is a front elevation view of a surgeon's console in
a robotic surgical system.
[0016] FIG. 1C is a front elevation view of a vision cart in a
robotic surgical system.
[0017] FIG. 2A is a side elevation view of an instrument arm.
[0018] FIG. 2B is a perspective view of a manipulator with an
instrument mounted.
[0019] FIG. 2C is a side elevation view of a portion of a camera
arm with a camera mounted.
[0020] FIG. 3 is a diagrammatic view of multiple cannulas and
associated instruments inserted through a body wall so as to reach
a surgical site.
[0021] FIG. 4A is a schematic view of a portion of a patient side
robotic manipulator that supports and moves a combination of a
curved cannula and a passively flexible surgical instrument.
[0022] FIG. 4B is a schematic view that shows a second patient side
robotic manipulator that supports and moves a second curved cannula
and passively flexible surgical instrument combination, added to
the FIG. 4A view.
[0023] FIG. 4C is a schematic view that shows an endoscopic camera
manipulator that supports an endoscope, added to the FIG. 4B
view.
[0024] FIG. 5 is a diagrammatic view of a flexible instrument.
[0025] FIG. 6 is a bottom view of a force transmission
mechanism.
[0026] FIG. 7 is a diagrammatic side view of a distal portion of a
surgical instrument.
[0027] FIG. 8 is a cutaway perspective view of a portion of an
instrument shaft.
[0028] FIG. 9 is a cutaway perspective view of a portion of another
instrument shaft.
[0029] FIG. 10 is a diagrammatic view of a curved cannula.
[0030] FIG. 10A is a diagrammatic view of an aligning key
feature.
[0031] FIGS. 11A and 11B illustrate cannula orientations.
[0032] FIGS. 12A, 12B, and 12C are diagrammatic views that show an
instrument shaft running through and extending from various cannula
configurations.
[0033] FIG. 13 is a schematic view that illustrates another curved
cannula and flexible instrument combination.
[0034] FIG. 14A is a diagrammatic plan view of a port feature.
[0035] FIG. 14B is a diagrammatic perspective view of a port
feature.
[0036] FIG. 15A is a diagrammatic cross-sectional view taken at a
cut line in FIG. 14A.
[0037] FIG. 15B shows a detail of a seal depicted in FIG. 15A.
[0038] FIG. 15C is a diagrammatic cross-sectional view taken at
another cut line in FIG. 14A.
[0039] FIG. 15D is a diagrammatic cross-sectional view that
illustrates an electrically conductive layer in a port feature.
[0040] FIG. 16A is a diagrammatic view of various skin and fascia
incisions.
[0041] FIG. 16B is a diagrammatic perspective cross-sectional view
of another port feature.
[0042] FIGS. 17A and 17B are diagrammatic views of yet another port
feature.
[0043] FIGS. 18A and 18B are diagrammatic views of yet another port
feature.
[0044] FIG. 19A is a perspective view of a cannula
insertion/stabilizing fixture.
[0045] FIG. 19B is another perspective view of a cannula
insertion/stabilizing fixture.
[0046] FIG. 19C is a diagrammatic perspective view of a cannula
stabilizing fixture.
[0047] FIGS. 20A-20D are diagrammatic views that illustrate another
way of inserting cannulas.
[0048] FIG. 21 is a diagrammatic view of a curved cannula and
various reference axes.
[0049] FIG. 22 is a diagrammatic view of a curved cannula and the
distal end of a flexible instrument with associated optical fiber
strain sensors.
[0050] FIG. 23 is a diagrammatic view of a control system
architecture.
DETAILED DESCRIPTION
[0051] This description and the accompanying drawings that
illustrate inventive aspects and embodiments should not be taken as
limiting--the claims define the protected invention. Various
mechanical, compositional, structural, electrical, and operational
changes may be made without departing from the spirit and scope of
this description and the claims. In some instances, well-known
circuits, structures, and techniques have not been shown or
described in detail in order not to obscure the invention. Like
numbers in two or more figures represent the same or similar
elements.
[0052] Further, this description's terminology is not intended to
limit the invention. For example, spatially relative terms--such as
"beneath", "below", "lower", "above", "upper", "proximal",
"distal", and the like--may be used to describe one element's or
feature's relationship to another element or feature as illustrated
in the figures. These spatially relative terms are intended to
encompass different positions (i.e., locations) and orientations
(i.e., rotational placements) of a device in use or operation in
addition to the position and orientation shown in the figures. For
example, if a device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be "above" or "over" the other elements or features. Thus, the
exemplary term "below" can encompass both positions and
orientations of above and below. A device may be otherwise oriented
(rotated 90 degrees or at other orientations) and the spatially
relative descriptors used herein interpreted accordingly. Likewise,
descriptions of movement along and around various axes includes
various special device positions and orientations. In addition, the
singular forms "a", "an", and "the" are intended to include the
plural forms as well, unless the context indicates otherwise. And,
the terms "comprises", "comprising", "includes", and the like
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. Components described as
coupled may be electrically or mechanically directly coupled, or
they may be indirectly coupled via one or more intermediate
components.
[0053] Elements described in detail with reference to one
embodiment may, whenever practical, be included in other
embodiments in which they are not specifically shown or described.
For example, if an element is described in detail with reference to
one embodiment and is not described with reference to a second
embodiment, the element may nevertheless be claimed as included in
the second embodiment.
[0054] The term "flexible" in association with a mechanical
structure or component should be broadly construed. In essence, the
term means the structure or component can be repeatedly bent and
restored to an original shape without harm. Many "rigid" objects
have a slight inherent resilient "bendiness" due to material
properties, although such objects are not considered "flexible" as
the term is used herein. A flexible mechanical structure may have
infinite degrees of freedom (DOF's). Examples of such structures
include closed, bendable tubes (made from, e.g., NITINOL, polymer,
soft rubber, and the like), helical coil springs, etc. that can be
bent into various simple and compound curves, often without
significant cross-sectional deformation. Other flexible mechanical
structures may approximate such an infinite-DOF piece by using a
series of closely spaced components that are similar to "vertebrae"
in a snake-like arrangement. In such a vertebral arrangement, each
component is a short link in a kinematic chain, and movable
mechanical constraints (e.g., pin hinge, cup and ball, live hinge,
and the like) between each link may allow one (e.g., pitch) or two
(e.g., pitch and yaw) DOF's of relative movement between the links.
A short, flexible structure may serve as, and be modeled as, a
single mechanical constraint (joint) that provides one or more
DOF's between two links in a kinematic chain, even though the
flexible structure itself may be a kinematic chain made of several
coupled links. Knowledgeable persons will understand that a
component's flexibility may be expressed in terms of its
stiffness.
[0055] In this description, a flexible mechanical structure or
component may be either actively or passively flexible. An actively
flexible piece may be bent by using forces inherently associated
with the piece itself. For example, one or more tendons may be
routed lengthwise along the piece and offset from the piece's
longitudinal axis, so that tension on the one or more tendons
causes the piece to bend. Other ways of actively bending an
actively flexible piece include, without limitation, the use of
pneumatic or hydraulic power, gears, electroactive polymer, and the
like. A passively flexible piece is bent by using a force external
to the piece. An example of a passively flexible piece with
inherent stiffness is a plastic rod or a resilient rubber tube. An
actively flexible piece, when not actuated by its inherently
associated forces, may be passively flexible. A single component
may be made of one or more actively and passively flexible portions
in series.
[0056] Aspects of the invention are described primarily in terms of
an implementation using a da Vinci.RTM. Surgical System
(specifically, a Model IS3000, marketed as the da Vinci.RTM. Si.TM.
HD.TM. Surgical System), manufactured by Intuitive Surgical, Inc.
of Sunnyvale, Calif. Knowledgeable persons will understand,
however, that inventive aspects disclosed herein may be embodied
and implemented in various ways, including robotic and non-robotic
embodiments and implementations. Implementations on da Vinci.RTM.
Surgical Systems (e.g., the Model IS3000; the Model IS2000,
marketed as the da Vinci.RTM. S.TM. HD.TM. Surgical System) are
merely exemplary and is not to be considered as limiting the scope
of the inventive aspects disclosed herein.
[0057] FIGS. 1A, 1B, and 1C are front elevation views of three main
components of a teleoperated robotic surgical system for minimally
invasive surgery. These three components are interconnected so as
to allow a surgeon, with the assistance of a surgical team, perform
diagnostic and corrective surgical procedures on a patient.
[0058] FIG. 1A is a front elevation view of the patient side cart
component 100 of the da Vinci.RTM. Surgical System. The patient
side cart includes a base 102 that rests on the floor, a support
tower 104 that is mounted on the base 102, and several arms that
support surgical tools (which include a stereoscopic endoscope). As
shown in FIG. 1A, arms 106a,106b are instrument arms that support
and move the surgical instruments used to manipulate tissue, and
arm 108 is a camera arm that supports and moves the endoscope. FIG.
1A also shows an optional third instrument arm 106c that is
supported on the back side of support tower 104, and that can be
positioned to either the left or right side of the patient side
cart as necessary to conduct a surgical procedure. FIG. 1A further
shows interchangeable surgical instruments 110a,110b,110c mounted
on the instrument arms 106a,106b,106c, and it shows endoscope 112
mounted on the camera arm 108. The arms are discussed in more
detail below. Knowledgeable persons will appreciate that the arms
that support the instruments and the camera may also be supported
by a base platform (fixed or moveable) mounted to a ceiling or
wall, or in some instances to another piece of equipment in the
operating room (e.g., the operating table). Likewise, they will
appreciate that two or more separate bases may be used (e.g., one
base supporting each arm).
[0059] FIG. 1B is a front elevation view of a surgeon's console 120
component of the da Vinci.RTM. Surgical System. The surgeon's
console is equipped with left and right multiple DOF master tool
manipulators (MTM's) 122a,122b, which are kinematic chains that are
used to control the surgical tools (which include the endoscope and
various cannulas). The surgeon grasps a pincher assembly 124a,124b
on each MTM 122, typically with the thumb and forefinger, and can
move the pincher assembly to various positions and orientations.
When a tool control mode is selected, each MTM 122 is coupled to
control a corresponding instrument arm 106 for the patient side
cart 100. For example, left MTM 122a may be coupled to control
instrument arm 106b and instrument 110a, and right MTM 122b may be
coupled to control instrument arm 106b and instrument 110b. If the
third instrument arm 106c is used during a surgical procedure and
is positioned on the left side, then left MTM 122a can be switched
between controlling arm 106a and instrument 110a to controlling arm
106c and instrument 110c. Likewise, if the third instrument arm
106c is used during a surgical procedure and is positioned on the
right side, then right MTM 122a can be switched between controlling
arm 106b and instrument 110b to controlling arm 106c and instrument
110c. In some instances, control assignments between MTM's
122a,122b and arm 106a/instrument 110a combination and arm
106b/instrument 110b combination may also be exchanged. This may be
done, for example, if the endoscope is rolled 180 degrees, so that
the instrument moving in the endoscope's field of view appears to
be on the same side as the MTM the surgeon is moving. The pincher
assembly is typically used to operate a jawed surgical end effector
(e.g., scissors, grasping retractor, needle driver, and the like)
at the distal end of an instrument 110.
[0060] Surgeon's console 120 also includes a stereoscopic image
display system 126. Left side and right side images captured by the
stereoscopic endoscope 112 are output on corresponding left and
right displays, which the surgeon perceives as a three-dimensional
image on display system 126. In an advantageous configuration, the
MTM's 122 are positioned below display system 126 so that the
images of the surgical tools shown in the display appear to be
co-located with the surgeon's hands below the display. This feature
allows the surgeon to intuitively control the various surgical
tools in the three-dimensional display as if watching the hands
directly. Accordingly, the MTM servo control of the associated
instrument arm and instrument is based on the endoscopic image
reference frame.
[0061] The endoscopic image reference frame is also used if the
MTM's are switched to a camera control mode. In the da Vinci.RTM.
Surgical System, if the camera control mode is selected, the
surgeon may move the distal end of the endoscope by moving one or
both of the MTM's together (portions of the two MTM's may be
servomechanically coupled so that the two MTM portions appear to
move together as a unit). The surgeon may then intuitively move
(e.g., pan, tilt, zoom) the displayed stereoscopic image by moving
the MTM's as if holding the image in the hands.
[0062] The surgeon's console 120 is typically located in the same
operating room as the patient side cart 100, although it is
positioned so that the surgeon operating the console is outside the
sterile field. One or more assistants typically assist the surgeon
by working within the surgical field (e.g., to change tools on the
patient side cart, to perform manual retraction, etc.).
Accordingly, the surgeon operates remote from the sterile field,
and so the console may be located in a separate room or building
from the operating room. In some implementations, two consoles 120
(either co-located or remote from one another) may be networked
together so that two surgeons can view and control tools at the
surgical site.
[0063] FIG. 1C is a front elevation view of a vision cart component
140 of the da Vinci.RTM. Surgical System. The vision cart 140
houses the surgical system's central electronic data processing
unit 142 and vision equipment 144. The central electronic data
processing unit includes much of the data processing used to
operate the surgical system. In various other implementations,
however, the electronic data processing may be distributed in the
surgeon console and patient side cart. The vision equipment
includes camera control units for the left and right image capture
functions of the stereoscopic endoscope 112. The vision equipment
also includes illumination equipment (e.g., Xenon lamp) that
provides illumination for imaging the surgical site. As shown in
FIG. 1C, the vision cart includes an optional 24-inch touch screen
monitor 146, which may be mounted elsewhere, such as on the patient
side cart 100. The vision cart 140 further includes space 148 for
optional auxiliary surgical equipment, such as electrosurgical
units and insufflators. The patient side cart and the surgeon's
console are coupled via optical fiber communications links to the
vision cart so that the three components together act as a single
teleoperated minimally invasive surgical system that provides an
intuitive telepresence for the surgeon. And, as mentioned above, a
second surgeon's console may be included so that a second surgeon
can, e.g., proctor the first surgeon's work.
[0064] FIG. 2A is a side elevation view of an illustrative
instrument arm 106. Sterile drapes and associated mechanisms that
are normally used during surgery are omitted for clarity. The arm
is made of a series of links and joints that couple the links
together. The arm is divided into two portions. The first portion
is the "set-up" portion 202, in which unpowered joints couple the
links. The second portion is powered, robotic manipulator portion
204 (patient side manipulator; "PSM") that supports and moves the
surgical instrument. During use, the set-up portion 202 is moved to
place the manipulator portion 204 in the proper position to carry
out the desired surgical task. The set-up portion joints are then
locked (e.g., with brake mechanisms) to prevent this portion of the
arm from moving.
[0065] FIG. 2B is a perspective view of the PSM 204 with an
illustrative instrument 110 mounted. The PSM 204 includes a yaw
servo actuator 206, a pitch servo actuator 208, and an insertion
and withdrawal ("I/O") actuator 210. An illustrative surgical
instrument 110 is shown mounted at an instrument mounting carriage
212. An illustrative straight cannula 214 is shown mounted to
cannula mount 216. Shaft 218 of instrument 110 extends through
cannula 214. PSM 204 is mechanically constrained so that it moves
instrument 110 around a stationary remote center of motion 220
located along the instrument shaft. Yaw actuator 206 provides yaw
motion 222 around remote center 220, pitch actuator 208 provides
pitch motion 224 around remote center 220, and I/O actuator 210
provides insertion and withdrawal motion 226 through remote center
220. The set up portion 202 is typically positioned to place remote
center of motion 220 at the incision in the patient's body wall
during surgery and to allow for sufficient yaw and pitch motion to
be available to carry out the intended surgical task. Knowledgeable
persons will understand that motion around a remote center of
motion may also be constrained solely by the use of software,
rather than by a physical constraint defined by a mechanical
assembly.
[0066] Matching force transmission disks in mounting carriage 212
and instrument force transmission assembly 230 couple actuation
forces from actuators 232 in PSM 204 to move various parts of
instrument 110 in order to position, orient, and operate instrument
end effector 234. Such actuation forces may typically roll
instrument shaft 218 (thus providing another DOF through the remote
center), operate a wrist 236 that provides yaw and pitch DOF's, and
operate a movable piece or grasping jaws of various end effectors
(e.g., scissors, graspers, electrocautery hooks, retractors,
etc.).
[0067] FIG. 2C is a side elevation view of a portion of a camera
arm 108 with an illustrative camera 112 mounted. Similar to the
instrument arm 106, the camera arm 108 includes a set-up portion
240 and a manipulator portion 242 (endoscopic camera manipulator;
"ECM"). ECM 242 is configured similarly to PSM 204 and includes a
yaw motion actuator 244, a pitch motion actuator 246, and an I/O
motion actuator 248. Endoscope 112 is mounted on carriage assembly
250 and endoscope cannula 252 is mounted on camera cannula mount
254. ECM 242 moves endoscope 112 around and through remote center
of motion 256.
[0068] During a typical surgical procedure with the robotic
surgical system described with reference to FIGS. 1A-2C, at least
two incisions are made into the patient's body (usually with the
use of a trocar to place the associated cannula). One incision is
for the endoscope camera instrument, and the other incisions are
for the necessary surgical instruments. Such incisions are
sometimes referred to as "ports", a term which may also mean a
piece of equipment that is used within such an incision, as
described in detail below. In some surgical procedures, several
instrument and/or camera ports are necessary in order to provide
the needed access and imaging for a surgical site. Although the
incisions are relatively small in comparison to larger incisions
used for traditional open surgery, there is the need and desire to
further reduce the number of incisions to further reduce patient
trauma and for improved cosmesis.
[0069] Single port surgery is a technique in which all instruments
used for minimally invasive surgery are passed through a single
incision in the patient's body wall, or in some instances through a
single natural orifice. Such methods may be referred to by various
terms, such as Single Port Access (SPA), Laparo Endoscopic
Single-site Surgery (LESS), Single Incision Laparoscopic Surgery
(SILS), One Port Umbilical Surgery (OPUS), Single Port Incisionless
Conventional Equipment-utilizing Surgery (SPICES), or Natural
Orifice TransUmbilical Surgery (NOTUS). The use of a single port
may done using either manual instruments or a robotic surgical
system, such as the one described above. A difficulty arises with
such a technique, however, because the single port constrains the
angle at which a surgical instrument can access the surgical site.
Two instruments, for example, are positioned nearly side-by-side,
and so it is difficult to achieve advantageous triangulation angles
at the surgical site. Further, since the instruments and endoscope
enter via the same incision, straight instrument shafts tend to
obscure a large part of the endoscope's field of view. And in
addition, if a robotic surgical system is used, then the multiple
manipulators may interfere with one another, due to both their size
and their motions, which also limits the amount of end effector
movement available to the surgeon.
[0070] FIG. 3 illustrates the difficulty of using a multi-arm
robotic surgical system for single port surgery. FIG. 3 is a
diagrammatic view of multiple cannulas and associated instruments
inserted through a body wall so as to reach a surgical site 300. As
depicted in FIG. 3, a camera cannula 302 extends through a camera
incision 304, a first instrument cannula 306 extends through a
first instrument incision 308, and a second instrument cannula 310
extends through a second instrument incision 312. It can be seen
that if each of these cannulas 302,306,310 were to extend through
the same (slightly enlarged) port 304, due to the requirement that
each move around a remote center of motion and also due to the bulk
and movement of the manipulators described above that hold the
cannulas at mounting fittings 302a,306a,310a, then very little
movement of the instrument end effectors is possible, and the
cannulas and instrument shafts can obscure the surgical site in the
endoscope's field of view.
[0071] For single port surgery using manual instruments, an attempt
has been made to use rigid, curved instrument shafts to improve
triangulation. Such curved shafts typically have a compound "S"
bend that inside the body allows them to curve away from the
incision and then back to the surgical site, and outside the body
to curve away from the incision to provide clearance for the
instrument handles and the surgeon's hands. These curved
instruments appear to be even more difficult to use than straight
shaft manual instruments, because the curved shafts further limit a
surgeon's ability to precisely move the instruments end effector
either by moving the shaft or by using a manually operated wrist
mechanism. Suturing, for example, appears to be extremely difficult
with such rigid curved shaft instruments. In addition, the
surgeon's ability to insert and withdraw such curved shaft
instruments directly between the incision and the surgical site is
limited because of their shape. And, due to their shape, rolling a
rigid curved instrument may cause a portion of the instrument shaft
to contact, and possibly damage, tissue without the surgeon's
knowledge.
[0072] For single port surgery using robotic surgical systems,
methods are proposed to provide increased controllable degrees of
freedom to surgical instruments. For example, the use of
telerobotically controlled "snake-like" instruments and associated
controllable guide tubes has been proposed as a way to access a
surgical site though a single incision. Similarly, the use of
instruments with a miniature mechanical parallel motion mechanism
has been proposed. See e.g., U.S. Patent Application Pub. No. US
2008/0065105 A1 (filed Jun. 13, 2007)(describing a minimally
invasive surgical system). While such instruments may ultimately be
effective, they are often mechanically complex. And, due to their
increased DOF actuation requirements, such instruments may not be
compatible with existing robotic surgical systems.
Curved Cannula System
[0073] FIG. 4A is a schematic view of a portion of a patient side
robotic manipulator that supports and moves a combination of a
curved cannula and a passively flexible surgical instrument. As
depicted in FIG. 4A, a telerobotically operated surgical instrument
402a includes a force transmission mechanism 404a, a passively
flexible shaft 406a, and an end effector 408a. Instrument 402a is
mounted on an instrument carriage assembly 212a of a PSM 204a
(previously described components are schematically depicted for
clarity). Interface discs 414a couple actuation forces from servo
actuators in PSM 204a to move instrument 402a components. End
effector 408a illustratively operates with a single DOF (e.g.,
closing jaws). A wrist to provide one or more end effector DOF's
(e.g., pitch, yaw; see e.g., U.S. Pat. No. 6,817,974 (filed Jun.
28, 2002) (disclosing surgical tool having positively positionable
tendon-actuated multi-disk wrist joint), which is incorporated
herein by reference) is optional and is not shown. Many instrument
implementations do not include such a wrist. Omitting the wrist
simplifies the number of actuation force interfaces between PSM
204a and instrument 402a, and the omission also reduces the number
of force transmission elements (and hence, instrument complexity
and dimensions) that would be necessary between the proximal force
transmission mechanism 404a and the distally actuated piece.
[0074] FIG. 4A further shows a curved cannula 416a, which has a
proximal end 418a, a distal end 420a, and a central channel 422a
that extends between proximal end 418a and distal end 420a. Curved
cannula 416a is, in one implementation, a rigid, single piece
cannula. As depicted in FIG. 4A, proximal end 418a of curved
cannula 416a is mounted on PSM 204a's cannula mount 216a. During
use, instrument 402a's flexible shaft 406a extends through curved
cannula 416a's central channel 422a so that a distal portion of
flexible shaft 406a and end effector 408a extend beyond cannula
416a's distal end 420a in order to reach surgical site 424. As
described above, PSM 204a's mechanical constraints (or,
alternately, preprogrammed software constraints in the control
system for PSM 204a) cause instrument 402a and curved cannula 416a
to move in pitch and yaw around remote center of motion 426 located
along cannula 416a, which is typically placed at an incision in the
patient's body wall. PSM 204a's I/O actuation, provided by carriage
212a, inserts and withdraws instrument 402a through cannula 416a to
move end effector 408a in and out. Details of instrument 402a,
cannula 416a, and the control of these two components is described
below.
[0075] FIG. 4B is a schematic view that shows a second patient side
robotic manipulator that supports and moves a second curved cannula
and passively flexible surgical instrument combination, added to
the FIG. 4A view. Components of the second PSM 204b, instrument
402b, and curved cannula 416b are substantially similar to, and
function in a substantially similar manner to, those described in
FIG. 4A. Curved cannula 416b, however, curves in a direction
opposite to the direction in which curved cannula 416a curves. FIG.
4B thus illustrates that two curved cannulas and associated
instruments, curving in opposite directions, are positioned to
extend through a single incision 428 in the patient's body wall 430
to reach surgical site 424. Each curved cannula initially angles
away from a straight line between the incision and the surgical
site and then curves back towards the line to direct the extended
instruments to the surgical site. By operating PSM's 204a and 204b
in pitch in yaw, the distal ends 420a,420b of the curved cannulas
move accordingly, and therefore instrument end effectors 404a and
404b are moved with reference to the surgical site (and
consequently, with reference to the endoscope's field of view). It
can be seen that although the remote centers of motion for the two
curved cannula and flexible instrument combinations are not
identical, they are sufficiently close enough (proximate) to one
another so that they can both be positioned at the single incision
428.
[0076] FIG. 4C is a schematic view that shows an endoscopic camera
manipulator that supports an endoscope, added to the FIG. 4B view.
Some previously used reference numbers are omitted for clarity. As
shown in FIG. 4C, ECM 242 holds endoscope 112 such that it extends
through single incision 428, along with the two curved cannula and
flexible instrument combinations. Endoscope 112 extends through a
conventional cannula 252 supported by cannula mount 254. In some
implementations, cannula 252 provides insufflation to a body
cavity. ECM 242 is positioned to place the endoscope 112's remote
center of motion at incision 428. As above, it can be seen that the
remote centers of motion for the two curved cannula and instrument
combinations and the endoscope 112 are not identical, and they may
be positioned sufficiently close to allow all to extend through the
single incision 428 without the incision being made unduly large.
In an example implementation, the three remote centers may be
positioned on approximately a straight line, as illustrated in FIG.
4C. In other implementations, such as ones described below, the
remote centers are not linearly aligned, yet are grouped
sufficiently close.
[0077] FIG. 4C also schematically illustrates that the PSM's
204a,204b and the ECM 242 may be positioned so that each has a
significantly improved volume in which to move in pitch and yaw
without interfering with each other. That is, if straight-shaft
instruments are used, then the PSM's must in general remain in
positions near one another to keep the shafts in a near parallel
relation for effective work through a single incision. But with the
curved cannulas, however, the PSM's can be placed farther from one
another, and so each PSM can in general move within a relatively
larger volume than with the straight-shaft instruments. In
addition, FIG. 4C illustrates how the curved cannulas 416 provide
an improved triangulation for the surgical instruments, so that the
surgical site 426 is relatively unobstructed in endoscope 112's
field of view 430.
[0078] FIG. 4C further illustrates that a port feature 432 may be
placed in incision 428. Cannulas 416a, 416b, and 252 each extend
through port feature 432. Such a port feature may have various
configurations, as described in detail below.
[0079] FIG. 5 is a diagrammatic view of an illustrative flexible
instrument 500 used with a curved cannula. Instrument 500 includes
a proximal end force transmission mechanism 502, a distal end
surgical end effector 504, and a shaft 506 that couples force
transmission mechanism 502 and end effector 504. In some
implementations, shaft 506 is passively flexible and includes three
sections--a proximal section 506a, a distal section 506c, and a
middle section 506b that is between proximal and distal sections
506a,506c. In some implementations, the sections 506a,506b,506c may
be each characterized by their different stiffnesses. Section 506a
is the portion of shaft 506 that extends from force transmission
mechanism 502 towards the curved cannula through which the other
sections of shaft 506 extend. Consequently, section 506a is
relatively stiff in comparison to the other sections 506b,506c. In
some implementations, section 506a may be effectively rigid.
Section 506b is relatively more flexible than the other two
sections 506a,506c. The majority of section 506b is within the
curved cannula during a surgical procedure, and so section 506b is
made relatively flexible to reduce friction with the inner wall of
the curved cannula, yet it is not made so flexible so that it
buckles during insertion under manual or servocontrolled operation.
Section 506c is relatively more stiff than section 506b, because
section 506c extends from the distal end of the curved cannula.
Accordingly, section 506c is made flexible enough so that it may be
inserted through the bend of the curved cannula, yet it is made
rigid enough to provide adequate cantilever support for end
effector 504. In some implementations, however, shaft sections
506a-506c each have the same physical structure--each being
composed of the same material(s), and the material(s) chosen to
have a bending stiffness acceptable for each section--so the
sections thus have the same stiffness. For instruments that require
an end effector roll DOF via shaft roll, all three sections
506a-506c are torsionally rigid enough to transmit roll motion from
the proximal end if the instrument to distal surgical end effector
504. An example is described in reference to FIG. 9, below. In one
implementation, shaft 506 is about 43 cm long.
[0080] FIG. 6 is a bottom view of an implementation of force
transmission mechanism 502. As shown in FIG. 6, the force
transmission mechanism of a surgical instrument used in a da
Vinci.RTM. Surgical System has been modified to eliminate the
mechanisms used to control a wrist mechanism on the instrument and
to control the jaw of an end effector (or other moveable part)
using only a single interface disk. Thus in one illustrative
implementation, one interface disk 602a rolls shaft 506 so as to
provide a roll DOF for end effector 504, and a second interface
disk 602b operates end effector 504's jaw mechanism. In one
implementation, a bulkhead in transmission mechanism 502 supports
coil tubes that run through the instrument shaft, as described in
detail below. Force transmission mechanism 502 may be coupled to
PSM 204 without any mechanical modifications required to the
PSM.
[0081] FIG. 6 also shows that implementations of force transmission
mechanism 502 may include electrically conductive interface pins
604 and an electronic data memory 606 that is electrically coupled
to interface pins 604. Parameters relevant to instrument 500 and
its operation (e.g., number of times the instrument has been used,
Denavit-Hartenberg parameters for control (described below), etc.)
may be stored in memory 606 and accessed by the robotic surgical
system during operation to properly use the instrument (see e.g.,
U.S. Pat. No. 6,331,181 (filed Oct. 15, 1999) (disclosing surgical
robotic tools, data architecture, and use), which is incorporated
herein by reference). In one implementation, kinematic data
specific to the curved cannula through which the instrument extends
may also be stored in memory 606, so that if the system detects
that a curved cannula is mounted (see e.g., FIG. 10 and associated
text below), the system may access and use the stored cannula data.
If more than one curved cannula kinematic configuration (e.g.,
different lengths, bend radii, bend angles, etc.) is used, then
data specific to each allowable configuration may be stored in the
associated instrument's memory, and the system may access and use
data for the specific cannula configuration that is mounted. In
addition, in some instances if the robotic surgical system senses
that a flexible instrument has been coupled to a manipulator that
holds a straight, rather than curved, cannula, then the system may
declare this situation to be an illegal state and prevent
operation.
[0082] FIG. 7 is a diagrammatic side view of an illustrative
implementation of a distal portion of surgical instrument 500. As
shown in FIG. 7, a proximal clevis 702 is coupled (e.g., laser
welded, soldered, etc.) to a sleeve 704, which in one instance is
formed of stainless steel. Sleeve 704 is coupled (e.g., crimped,
glued, etc.) in turn to the distal end of shaft 506. Other known
coupling methods may be used. Proximal clevis 702 is illustrative
of components of many surgical instrument end effectors that may be
used, including needle drivers, bullet nose dissectors, curved
scissors, Maryland dissectors, clip appliers, cautery hooks,
etc.
[0083] FIG. 8 is a cutaway perspective view that shows an
illustrative structure of a portion of instrument shaft 506. Two
tension elements 802a,802b extend through a distal portion of shaft
506 and are coupled to operate the end effector (shown
diagrammatically; e.g., a 5 mm class surgical end effector used in
da Vinci.RTM. Surgical System instruments). Tension elements
802a,802b may be separate, or they may be parts of the same element
that, for example, wraps around a pulley in the end effector. In
one implementation, tension elements 802a,802b are 0.018-inch
tungsten wire. As shown in FIG. 8, proximal ends of tension
elements 802a,802b are coupled (e.g., crimped, etc.) to distal ends
of second tension elements 804a,804b that further extend proximally
through most of shaft 506. In one implementation, tension elements
804a,804b are 0.032-inch stainless steel hypotubes. At the proximal
end (not shown) tension elements 804a,804b are coupled to
transmission mechanism 502 using wires coupled in a similar
manner.
[0084] As shown in FIG. 8, tension elements 804a,804b extend
through support tubes 806a,806b respectively, which guide tension
elements 804a,804b and keep them from buckling or kinking within
shaft 506. In one implementation, support tubes 806a,806b are
stainless steel (e.g., 304V (vacuum melt that reduces friction))
coil tubes (0.035-inch inner diameter; 0.065-inch outer diameter),
and other materials and structures may be used. To reduce friction
as each tension element slides inside its support tube, a friction
reducing sheath 808a,808b is placed between the tension element and
the inner wall of the support tube. In one implementation, sheaths
808a,808b are polytetrafluoroethylene (PTFE), and other materials
may be used. Both support tubes 806a,806b are placed within a
single inner shaft tube 810. In one implementation, a flat-spiral
stainless steel wire is used for inner shaft tube 810 to provide
torsional stiffness during roll. An outer shaft tube 812 (e.g.,
braided stainless steel mesh or other material suitable to protect
the shaft components) surrounds inner shaft tube 810. An elastomer
skin 814 (e.g., Pellothane.RTM., or other suitable material)
surrounds the outer shaft tube 812. Skin 814 protects the inner
components of shaft 506 from direct contamination by, e.g., body
fluids during surgery, and the skin facilitates shaft 506 sliding
within the curved cannula. In some implementations shaft 506 is
approximately 5.5 mm (0.220 inches) outer diameter.
[0085] In one example implementation, the support tube and tension
element assemblies may be dip coated in PTFE to provide a "sheath"
that reduces friction. The space between the coils is filled in by
the dip coating material to form a tube. In another example
implementation, wire is pre-coated before the coil is wound, and
the coil is then baked to re-melt the coating and form the solid
tube. The ends of the tube may be sealed around the tension
elements to prevent contamination (e.g., body fluids) from entering
between the tension element and the coil tube.
[0086] Shaft 506 may include additional components. As shown in
FIG. 8, for example, in some implementations one or more stiffening
rods 816 run through various portions of shaft 506. The number,
size, and composition of rods 816 may be varied to provide the
various stiffnesses of portions 506a-506c, as described above. For
example, in some implementations rods 816 are stainless steel. In
addition, some implementations one or more additional rods 818 of
another material may run through one or more portions of shaft 506.
For example, FIG. 8 shows a second rod of polyaryletheretherketone
(PEEK) that in one implementation runs through distal section 506c
to provide stiffness in addition to the stiffness from rods 516. In
addition, one or more supplemental tubes to provide, e.g., suction
and/or irrigation may be included in shaft 506, either in addition
to or in place of the stiffening rods. And, additional tension
elements may be included to operate, e.g., an optional multi-DOF
wrist mechanism at the distal end of the instrument shaft.
[0087] FIG. 9 is a cutaway perspective view that shows a second
illustrative structure of a portion of instrument shaft 506.
Tension elements 902a, 902b, 904a, and 904b are similar to tension
elements 802a, 802b, 804a, and 804d described above. The tension
elements are each routed through individual channels in
multi-channel support tube 906. In one implementation, tube 906 is
a fluorinated ethylene propylene (FEP) extrusion with multiple
channels 908, and other materials may be used. FEP provides a
low-friction surface against which the tension elements slide. One
or more stiffening rods (not shown) similar to those disclosed
above in FIG. 8 and associated text may be routed through various
other channels 908 in support tube 906 to provide desired
stiffnesses for each of the instrument shaft sections 506a-506c. A
seven-channel tube 906 is shown in FIG. 9, and a stiffening rod or
other element may be inserted into the center channel. Additional
cables, e.g., to operate an optional multi-DOF wrist mechanism at
the distal end of shaft 506, may be routed through other channels
in tube 906. Alternatively, other functions, such as suction and/or
irrigation, may be provided through the channels.
[0088] FIG. 9 further shows a shaft body tube 910 (e.g., extruded
PEEK or other suitable material) surrounding support tube 908 to
provide axial and torsional stiffness to shaft 506. An outer skin
or coating 912 surrounds body tube 910 to reduce friction as shaft
506 slides inside the curved cannula and to protect the shaft
components. In one implementation, skin 912 is a 0.005-inch layer
of FEP that is heat shrunk around support tube 910, and other
suitable materials may be used. In one implementation of the
structure shown in FIG. 9, the shaft 506 outer diameter is
approximately 5.5 mm (0.220 inches), with a single extrusion PEEK
body tube having an outer diameter of approximately 5.0 mm and an
inner diameter of about 3.5 mm. PEEK is used because its stiffness
(modulus of elasticity, or Young's modulus) is low enough to allow
bending with low enough radial force to limit friction inside the
curved cannula so that instrument I/O is not affected in a
meaningful way, but its modulus of elasticity is high enough to
provide good cantilever beam stiffness for the shaft distal portion
506c that extends beyond the distal end of the curved cannula, to
resist buckling of any portion of the shaft between the
transmission mechanism and the proximal end of the cannula, and to
transmit roll motion and torque along the length of the instrument
shaft with adequate stiffness and precision.
[0089] Primarily due to friction, as the bend radius of a curved
cannula decreases, instrument shaft stiffness must also decrease.
If an isotropic material is used for the instrument shaft, such as
is illustrated in association with FIG. 9, then the stiffness of
the shaft portion that extends from the cannula's distal end is
also reduced. At some point, either the stiffness of the shaft's
extended distal end or the stiffness of the shaft portion between
the transmission mechanism and the cannula may become unacceptably
low. Therefore, a range of stiffnesses may be defined for an
isotropic material shaft of fixed dimensions, depending on a
cannula's bend radius and inner diameter.
[0090] FIG. 10 is a diagrammatic view of an illustrative curved
cannula 416. As shown in FIG. 10, cannula 416 includes a mounting
section 1002 and cannula body section 1004. The mounting section
1002 is configured to be mounted on a robotic system manipulator
(e.g., PSM 204). In some implementations, one or more features 1006
are placed on the mounting section 1002 to be sensed by sensors
1008 in the manipulator's cannula mount. The presence of a feature
1006 as sensed by the sensors 1008 may indicate, e.g., that the
cannula is properly mounted and the type of cannula (e.g., straight
or curved, cannula length, curve radius, etc.). In one
implementation the features 1006 are raised annular metal rings and
the corresponding sensors 1008 are Hall effect sensors.
[0091] Mounting section 1002 may also include a mechanical key
feature 1009 that mates with a corresponding feature on the
manipulator to ensure that the cannula is mounted with the proper
orientation with reference to the manipulator's insertion axis. In
this way, for example, "left" and "right" curving cannulas may be
made. In addition, to distinguishing left versus right curve
orientation, the keyed feature may be used to ensure that the
cannula is rolled at the proper angle in the manipulator mount so
that instruments approach the surgical site at a desired angle.
Knowledgeable persons will understand that many various mechanical
key features may be used (e.g., mating pins/holes, tabs/grooves,
balls/detents, and the like). FIG. 10A illustrates one example key
feature. As shown in FIG. 10A, key feature 1030 is attached (e.g.,
welded) to the side of a mounting bracket 1032 for a curved
cannula. Key feature 1030 includes a recess 1034 that receives a
portion of a robotic manipulator's cannula mounting bracket and two
vertical alignment pins 1036a and 1036b. Alignment pins 1036a and
1036b mate with corresponding alignment holes in the manipulator's
mounting bracket to ensure the cannula's proper roll orientation
with reference to the manipulator.
[0092] FIGS. 11A and 11B are diagrammatic views of the distal ends
1102a and 1102b of two curved cannulas as a surgeon might see them
in the surgeon's console's 3-D display 1104, which outputs images
captured in the endoscope's field of view. In the display, the
curved cannulas extend away from the endoscope to enable the
instruments 1106a and 1106b to reach tissue 1108 at the surgical
site. The cannulas may be mounted on the manipulators at various
roll angles, or the manipulators may be oriented during surgery, so
that the instruments approach the surgical site at various angles.
Accordingly, the cannula roll orientations may described in several
ways. For example, the cannula roll angles may be described in
relation to each other. FIG. 11A shows that in one implementation
the cannulas may be oriented with their distal curves lying
approximately in a single common plane, so that the instruments
extend from directly opposite angles towards the surgical site.
FIG. 11B shows that in one implementation the cannulas may be
oriented with their distal curves lying in planes that are angled
with reference to each other, e.g., approximately 60 degrees as
shown, so that the instruments extend from offset angles towards
the surgical site. Many cannula curve plane relation angles are
possible (e.g., 120, 90, 45, 30, or zero degrees). Another way to
express the cannula roll orientation is to define it as the angle
between the plane that includes the cannula's curve and a plane of
motion for one of the manipulator's degrees of freedom (e.g.,
pitch). For example, a cannula may be mounted so that its curve
lies in a plane that is angled at 30 degrees to the manipulator's
pitch DOF. Accordingly, one illustrative way to obtain the position
of the instrument cannulas as shown in FIG. 11B is to position the
two PSM's facing one another with their pitch motion planes
approximately parallel (the planes will be slightly offset so that
the two cannulas do not intersect at their centers of motion).
Then, each curved cannula is oriented at approximately 30 degrees
with reference its corresponding PSM's pitch motion plane.
[0093] Referring again to FIG. 10, cannula body section 1004 is in
some implementations divided into a proximal section 1004a, a
middle section 1004b, and a distal section 1004c. Proximal section
1004a is straight, and its length is made sufficient to provide
adequate movement clearance for the supporting PSM. Middle section
1004b is curved to provide the necessary instrument triangulation
to the surgical site from a manipulator position that provides
sufficient range of motion to complete the surgical task without
significant collisions. In one implementation, middle section 1004b
is curved 60 degrees with a 5-inch bend radius. Other curve angles
and bend radii may be used for particular surgical procedures. For
example, one cannula length, curve angle, and bend radius may be
best suited for reaching from a particular incision point (e.g., at
the umbilicus) towards one particular anatomical structure (e.g.,
the gall bladder) while another cannula length, bend angle, and/or
bend radius may be best suited for reaching from the particular
incision point towards a second particular anatomical structure
(e.g., the appendix). And, in some implementations two cannulas
each having different lengths and/or bend radii may be used.
[0094] The relatively tight clearance between the curved section's
inner wall and the flexible instrument that slides inside requires
that the curved section's cross-section be circular or
near-circular shape throughout its length. In some implementations
the curved cannula is made of 304 stainless steel (work hardened),
and the curved section 1004b is bent using, e.g., a bending fixture
or a computer numerical controlled (CNC) tube bender. For a 5.5 mm
(0.220-inch) outer diameter instrument, in some implementations the
curved cannula's inner diameter is made to be approximately 0.239
inches, which provides an acceptable tolerance for inner diameter
manufacturing variations that will still provide good sliding
performance for the instrument shaft.
[0095] Distal section 1004c is a short, straight section of the
cannula body. Referring to FIG. 12A, it can be seen that due to the
small space (shown exaggerated for emphasis) between the instrument
shaft outer diameter and the cannula inner diameter, and due to the
instrument shaft's resiliency (although passively flexible, it may
retain a tendency towards becoming straight), the distal section
1202 of the instrument shaft contacts the outer lip of the
cannula's distal end. Consequently, if the curved cannula ends at
curved section 1004b, the distal section 1202 of the instrument
extends out of the cannula at a relatively larger angle (again,
shown exaggerated) with reference to the cannula's extended
centerline 1204. In addition, the angle between the instrument
shaft and the outer lip causes increased friction (e.g., scraping)
during instrument withdrawal. As shown in FIG. 12B, however, adding
distal section 1004c to the cannula lessens the angle between the
distal section 1202 and the cannula's extended centerline 1204 and
also lessens the friction between the outer lip and the instrument
shaft.
[0096] As shown in FIG. 12C, in some implementations, a sleeve 1206
is inserted into the distal end of distal section 1004c. Sleeve
1206 necks down the curved cannula's inner diameter at the distal
end, and so further assists extending the distal section 1202 of
the instrument shaft near the cannula's extended centerline 1204.
In some implementations sleeve 1206's outer lip is rounded, and
sleeve 1206's inner diameter is relatively close to the instrument
shaft's outer diameter. This helps reduce possible tissue damage by
preventing tissue from being pinched between the instrument shaft
and the cannula during instrument withdrawal. In some
implementations sleeve 1206 is made of 304 stainless steel and is
approximately 0.5 inches long with an inner diameter of
approximately 0.225 inches. Sleeve 1206 may also be made of a
friction reducing material, such as PTFE. In an alternate
implementation, rather than using a separate sleeve 1206, the
distal end of the curved cannula may be swaged to reduce the
cannula's inner diameter so as to produce a similar effect.
[0097] FIG. 13 is a schematic view that illustrates an alternate
implementation of a curved cannula and flexible instrument
combination. Instead of a simple C-shaped bend as described above,
curved cannula 1302 has a compound S-shaped bend (either planar or
volumetric). In one illustrative implementation, each bend has
about a 3-inch bend radius. Distal bend section 1304 provides
triangulation for the surgical instrument, and proximal bend 1306
provides clearance for, e.g., PSM 204b (alternatively, in a manual
implementation, for the surgical instrument handles and the
surgeon's hands). As depicted, passively flexible shaft 404b of
robotically controlled surgical instrument 402b extends through
curved cannula 1302 and beyond the cannula's distal end 1308. A
second curved cannula and flexible instrument combination is
omitted from the drawing for clarity. The use of S-shaped curved
cannulas is similar to the use of C-shaped curved cannulas as
disclosed herein. For an S-shaped cannula, however, in a reference
frame defined for the endoscope's field of view, the manipulator
that controls the instrument is positioned on the same side of the
surgical site as the corresponding end effector. Since the multiple
bends in the S-shaped cannula cause contact between the instrument
shaft and the cannula wall at more points along the length of the
cannula than the C-shaped cannula, with similar normal forces at
each point, the I/O and roll friction between the instrument and
the cannula is relatively higher with an S-shaped cannula.
Port Feature
[0098] FIG. 14A is a diagrammatic plan view of an illustrative
implementation of a port feature 1402 that may be used with curved
cannula and instrument combinations, and with an endoscope and one
or more other instruments, as described herein. FIG. 14B is a top
perspective view of the implementation shown in FIG. 14A. Port
feature 1402 is inserted into a single incision in a patient's body
wall. As shown in FIG. 14A, port feature 1402 is a single body that
has five channels that extend between a top surface 1404 and a
bottom surface 1406. A first channel 1408 serves as an endoscope
channel and is sized to accommodate an endoscope cannula. In
alternative implementations, channel 1408 may be sized to
accommodate an endoscope without a cannula. As shown in FIG. 14A,
endoscope channel 1404 is offset from port feature 1402's central
axis 1410. If a surgical procedure requires insufflation, it may be
provided via well known features on the endoscope cannula.
[0099] FIG. 14A shows two more channels 1412a and 1412b that serve
as instrument channels and that are each sized to accommodate a
curved cannula as described herein. Channels 1412a,1412b extend
through port feature 1402 at opposite angles to accommodate the
positioning of the curved cannulas. Thus, in some implementations
channels 1412a,1412b extend across a plane that divides the port
feature into left and right sides in an orientation shown in FIG.
14A. As shown in FIG. 14A, the instrument channels 1412a and 1412b
are also offset from central axis 1410. During use, the remote
centers of motion for the endoscope and instrument cannulas will be
generally at middle vertical positions within their respective
channels. By horizontally offsetting the endoscope channel 1408 and
the instrument channels 1412a,1412b from the central axis 1410, a
center point of this group of remote centers can be positioned
approximately in the center of the port feature (i.e., in the
center of the incision). Placing the remote centers close together
minimizes patient trauma during surgery (e.g., due to tissue
stretching during cannula motion). And, the port feature keeps the
cannulas close to one another but resists the tendency for tissue
to force the cannulas towards one another, thus preventing the
cannulas from interfering with one another. Various channel angles
may be used in various implementations in order to accommodate the
particular configurations of the curved cannulas being used or to
facilitate the required curved cannula placement for a particular
surgical procedure.
[0100] FIG. 14A also shows two illustrative optional auxiliary
channels 1414 and 1416 that extend vertically through port feature
1402 (the number of auxiliary channels may vary). The first
auxiliary channel 1414's diameter is relatively larger than the
second auxiliary channel 1416' diameter (various sized diameters
may be used for each auxiliary channel). First auxiliary channel
1414 may be used to insert another surgical instrument (manual or
robotic, such as a retractor or a suction instrument; with or
without a cannula) through port feature 1402. As shown in FIG. 14A,
endoscope channel 1408, instrument channels 1412a,1412b, and first
auxiliary channel 1414 each include a seal (described below), and
second auxiliary channel 1416 does not. And so, second auxiliary
channel 1416 may likewise be used to insert another surgical
instrument, or it may be used for another purpose better served by
not having a seal in the channel, such as to provide a channel for
a flexible suction or irrigation tube (or other non-rigid
instrument), or to provide a channel for insufflation or evacuation
(insufflation may be done using typical features on the endoscope
cannula or other cannula).
[0101] FIG. 14A shows that in some implementations, a port
orientation feature 1418 may be positioned on top surface 1404.
During use, the surgeon inserts port feature 1402 into the incision
and then orients the port feature so that orientation indicator
1418 is generally in the direction of the surgical site. Thus the
port feature is oriented to provide the necessary positions for the
endoscope and curved cannulas in order to carry out the surgical
procedure. Orientation feature 1418 may made in various ways, such
as molded into or printed on top surface 1404. Likewise, FIG. 14A
shows that in some implementations instrument port identification
features 1420a and 1420b (the circled numerals "1" and "2" are
shown) may be each positioned near one of the two instrument ports
to identify the instrument channel. A similar identification
feature may be placed on cannulas intended to be used on "left" or
"right" sides, so that medical personnel may easily place a curved
cannula in its proper port channel by matching the cannula and port
channel identifications.
[0102] In some implementation port feature 1402 is made of a single
piece of injection molded silicone having a durometer value of
about 15 Shore A. Other configurations of port feature 1402 may be
used, including multi-part port features with secondary cannulas
that can accommodate, e.g., both the endoscope and curved cannulas
as described herein.
[0103] Referring to FIG. 14B, in some instances the top surface
1404 and the bottom surface 1406 (not shown) are made concave. FIG.
14B also shows that in some instances port feature 1402 is waisted.
The waist 1422 provides a top flange 1424 and a bottom flange 1426
that help hold port feature 1402 in position within the incision.
Since port feature 1402 may be made of a soft, resilient material,
the flanges 1424,1426 formed by waist 1422 and the concave top and
bottom surfaces are easily deformed to allow the surgeon to insert
the port feature into the incision, and then the flanges return to
their original shape to hold the port feature in place.
[0104] FIG. 15A is a diagrammatic cross-sectional view taken at cut
line A-A in FIG. 14, and it illustrates how channel 1408b passes
from the top to the bottom surfaces at an angle from one side to
the other through port feature 1402. Channel 1408a is similarly
routed in the opposite direction. The vertical position at which
the two channels cross (in the FIG. 15A orientation, channel 1412a
(not shown) is closer to the viewer, crossing the port feature from
upper right to lower left) is approximately the vertical location
of the respective cannula remote centers of motion when properly
inserted. As mentioned above, in some implementations a seal may be
placed in one or more of the channels through port feature 1402,
and FIG. 15A shows an example of such a seal illustratively
positioned at the vertical location of the cannula remote center of
motion.
[0105] FIG. 15B is a detailed view of an example implementation of
a seal 1502 within instrument channel 1412b. As shown in FIG. 15B,
seal 1502 includes an integrally molded solid ring 1504 that
extends from channel 1412b's inner wall 1506 inwards towards
channel 1412b's longitudinal centerline. A small opening 1508
remains in the center of ring 1504 to allow the ring to stretch
open around an inserted object, yet the opening is generally small
enough to prevent any significant fluid passage (e.g., insufflation
gas escape). Thus the seals allow for insufflation (e.g., though an
auxiliary channel in the port feature) before any instruments
(e.g., cannulas) are inserted. The seals also improve the seal
between the port feature and the cannulas when the port feature is
flexed, and the channel shapes are consequently distorted, by
cannula movement during surgery.
[0106] Knowledgeable persons will understand that various other
ways to implement an effective seal may be used. For example, in
another seal implementation, an integrally molded resilient
membrane fully blocks the channel, and the membrane is pierced the
first time an object is inserted though the channel. The membrane
then forms a seal with the object. In yet other implementations, a
seal that is a separate piece may be inserted into the channel. For
instance, an annular detent may be molded in channel wall 1506, and
then a seal may be positioned and held in the detent.
[0107] FIG. 15C is a diagrammatic cross-sectional view taken at cut
line B-B in FIG. 14A. Cut line B-B is taken through endoscope
channel 1408's centerline, and so cut line B-B does not include the
auxiliary channel 1414 or 1416 centerlines. FIG. 15C illustrates
that in some implementations endoscope channel 1408 includes a seal
1508, and auxiliary channel 1414 includes a seal 1510, but
auxiliary channel 1416 has no seal. FIG. 15C further illustrates
that seals 1508 and 1510 are similar to seal 1502, although various
seals may be used as described above.
[0108] FIG. 15D is a diagrammatic cross-sectional view taken at cut
line A-A in FIG. 14, and it illustrates that in some
implementations there is an electrically conductive silicone layer
1512 that extends horizontally across the middle of the port
feature (e.g., at waist 1422, as shown). The conductive layer 1512
is shown spaced midway between the port feature's top and bottom
surfaces, and so it incorporates seals as described above. In other
implementations the electrically conductive layer may be at another
vertical position that does not incorporate the seals, or two or
more electrically conductive layers may be used. In some
implementations, the interior of the channels are necked down at
the conductive layer but not necessarily configured as seals, so as
to provide the necessary electrical contact between the conductive
layer and the instrument. In one implementation, conductive layer
1512 is integrally molded with upper portion 1514 and lower portion
1516 of the port feature. The electrically conductive silicone may
have a higher durometer value than the upper and lower portions due
to the necessary additives, but since it is located at
approximately the level of the cannula centers of motion, the
higher stiffness does not significantly affect cannula movement as
compared to a similar port feature without the electrically
conductive layer. This electrically conductive layer forms an
electrically conductive path between the patient's body wall, which
is in contact with the port feature's outer surface, and the
cannula and/or instrument that passes through the channel. This
electrically conductive path provides a path to electrical ground
during electrocautery.
[0109] As described above, in some cases port feature 1402 may be
inserted through the entire body wall. In other cases, however, a
single incision may not be made through the entire body wall. For
example, a single incision may include a single percutaneous
incision made at the umbilicus (e.g., in a Z shape) and multiple
incisions in the underlying fascia. Accordingly, in some cases the
port feature may be eliminated, and while each of the endoscope
cannula and curved cannulas extend through the single percutaneous
incision, the cannulas each pass through, and may be supported by,
separate incisions in the fascia. FIG. 16A is a diagrammatic view
that illustrates portions of endoscope cannula 1602, and left and
right curved cannulas 1604a and 1604b passing though a single skin
incision 1606, and then each through separate fascia incisions
1608. In some instances, operating room personnel may desire
additional support for the cannulas in such a single
percutaneous/multiple facial incision (e.g., while docking the
inserted cannulas to their associated robotic manipulators). In
such instances, a port configured similar to top portion 1514 (FIG.
15D) or to a combined top portion 1514 and conductive layer 1512
may be used.
[0110] FIG. 16B is a diagrammatic perspective cross-sectional view
of another port feature that may be used with a single skin
incision/multiple fascia incisions procedure. Port feature 1620 is
similar in configuration to port feature 1402, and features
described above (e.g., orientation and port indicators, seals where
applicable, soft resilient material, etc.) may apply to port
feature 1620 as well. Port feature 1620 has a body with a generally
cylindrical shape that includes a top surface 1622, a bottom
surface 1624, and a narrowed sidewall waist 1626 between the top
and bottom surfaces. Consequently, a top flange 1628 and a bottom
flange 1630 are formed between the sidewalls and the top and bottom
surfaces. During use, the skin is held in the waist 1626 between
the upper and lower flanges, and the bottom surface 1624 and bottom
flange 1630 rest on the fascia layer underlying the skin.
[0111] FIG. 16B further shows four illustrative ports that extend
between the port feature's top and bottom surfaces. Channel 1632 is
an endoscope channel, and channel 1634 is an auxiliary channel,
similar to such channels described above with reference to port
feature 1402. Likewise, channels 1636a and 1636b are angled
instrument channels that are similar to such channels described
above, channel 1636b angling from top right towards bottom left as
shown, and channel 1636a angling from top left towards bottom right
(hidden from view). Unlike port feature 1402's instrument channels,
however, the centerlines of port feature 1620's instrument channels
1636a and 1636b do not extend across the port feature's vertical
midline. Instead, the angled instrument channels stop at port
feature 1620's midline, so that the remote centers of motion of the
cannulas and instruments are positioned at the underlying fascia
incisions (an illustrative center of motion position 1638 is
illustrated). Thus it can be seen that the instrument channels'
exit locations on the port feature's bottom surface may be varied
so as to place the centers of motion at a desired location with
reference to a patient's tissue.
[0112] For some surgical procedures, the straight line between a
single incision and a surgical site (e.g., between the umbilicus
and the gall bladder) begins to approach being at an acute angle
relative to the patient's coronal (frontal) plane. Consequently,
the cannulas enter the single incision at a relatively small
(acute) angle with reference to the skin surface, and the body wall
twists and exerts a torsion on the cannulas/instruments or on the
port. FIG. 17A is a diagrammatic top view, and FIG. 17B is a
diagrammatic side view, of yet another port feature 1702 that may
be used to guide and support two or more cannulas entering through
a single incision. As shown in FIGS. 17A and 17B, port feature 1702
includes an upper funnel section 1704, a lower front tongue 1706,
and a lower back tongue 1708. In some implementations, the funnel
section and tongues are a single piece. Port feature 1702 may be
formed of for example, relatively stiff molded plastic such as
PEEK, polyetherimide (e.g., Ultem.RTM. products), polyethylene,
polypropylene, and the like, so that port feature 1702 generally
holds its shape during use. When positioned in an incision 1710,
the lower tongues 1706,1708 are inside the body, and the funnel
section 1704 remains outside the body. As shown in the figures, in
some implementations funnel section 1704 is shaped as an oblique
circular or elliptical cone, which reduces interference with
equipment positioned over the funnel section when the port feature
is twisted in the incision as described below. It can be seen that
once in position, the distal end 1712 of funnel section 1704 may be
pressed towards the skin surface. This action causes the waist
section 1714 between the upper funnel portion and the lower tongues
to twist in the incision, which effectively reorients the incision,
and so it provides a more resistance free path to the surgical
site. The front tongue prevents port feature 1702 from coming out
of the incision during this twisting. In addition, pushing down on
distal end 1712 of the funnel section raises the distal end 1716 of
the front tongue. In some implementations, the front tongue may be
sized and shaped to retract tissue as the distal end of the tongue
is raised. The back tongue 1708 also helps keep port feature 1702
in the incision.
[0113] Port feature 1702 also includes at least two access channels
to accommodate endoscope and instrument cannulas. As illustrated in
FIG. 17A, in some implementations four example channels are within
waist portion 1714. An endoscope cannula channel 1720 is placed in
the middle of waist portion 1714, and three instrument cannula
channels 1722 are positioned around endoscope cannula channel 1720.
In some implementations the channels are formed in the same single
piece as the funnel section and the tongues. In other
implementations, the channels are formed in a cylindrical piece
1723 that is mounted to rotate as indicated by arrows 1723a in
waist section 1714. In some implementations, instrument cannula
channels 1722 are each formed in a ball joint 1724, which is
positioned in waist section 1714 (e.g., directly, or in the
cylindrical piece). The remote centers of motion of the cannulas
are positioned in the ball joints, which then allow the cannulas to
easily pivot within port feature 1702. In other implementations,
the channels are configured to receive a ball that is affixed (e.g.
press fit) to a cannula at the remote center of motion, and the
cannula ball then pivots in the channel as a ball joint. In some
implementations, the top and bottom surfaces of the waist section
(e.g., the top and bottom surfaces of the cylindrical piece) may be
beveled to allow for increased range of motion of the cannula
moving in the ball joint. In some implementations, the endoscope
cannula channel 1720 does not include a ball joint. In some
implementations, an endoscope and/or instruments with rigid shafts
may be routed through their respective channels without
cannulas.
[0114] FIG. 18A is a diagrammatic top view, and FIG. 18B is a
diagrammatic side view, of still another port feature 1802 that may
be used to guide and support two or more cannulas entering through
a single incision. Port feature 1802's basic configuration is
similar to that of port feature 1702--e.g., the funnel section,
front tongue, and channels are generally similar. In port feature
1802, however, back tongue 1804 may be rotated from a position
aligned with front tongue 1806, as indicated by alternate position
1808, to a position opposite the front tongue, as shown in FIG.
18B. Therefore, back tongue 1804 may be made relatively longer than
back tongue 1708 (FIG. 17B), and port feature 1802 can still be
inserted into a single small incision. Back tongue 1804 is aligned
with front tongue 1806 when port feature 1802 is positioned in the
incision, and then it is rotated to the back position when the port
feature is in place. In one implementation, back tongue 1804 is
coupled to the rotating cylinder that contains the channels, as
described above, and a tab 1810, located inside the funnel section,
on the cylinder piece is rotated as indicated by the arrows from
its alternate insertion position 1812 towards the front to position
the back tongue for surgical use.
[0115] Aspects of the port features as described herein are not
confined to use with one or more curved cannulas, and such port
features may be used, for example, with straight instrument
cannulas, rigid instrument shafts (with or without cannulas), and
for both robotic and manual surgery.
Insertion Fixture
[0116] In multi-port minimally invasive surgery, the endoscope is
typically the first surgical instrument to be inserted. Once
inserted, the endoscope can be positioned to view other cannula and
instrument insertions so that an instrument does not inadvertently
contact and damage tissue. With a single incision, however, once an
endoscope is inserted, the other cannulas and instruments are
inserted at least initially outside the endoscope's field of view.
And, for curved cannulas, it is difficult to ensure that a cannula
tip will be moved directly into the endoscope's field of view
without contacting other tissue. In addition, keeping the cannulas
properly positioned and oriented as the robotic manipulators are
adjusted and then coupled (docked) to the cannulas may require
considerable manual dexterity involving more than one person.
Therefore, ways of safely and easily inserting multiple instruments
through a single incision are needed. During some surgical
procedures, port features such as those described above may provide
adequate ways of safely inserting multiple instruments. During
other surgical procedures, or due to surgeon preference, other ways
to safely insert multiple instruments may be used.
[0117] FIG. 19A is a perspective view of an example of a cannula
insertion fixture 1902. As shown in FIG. 19A, insertion fixture
1902 is capable of guiding an endoscope cannula and two curved
instrument cannulas into a single incision. Other implementations
may guide more or fewer cannulas. Insertion fixture 1902 includes a
base 1904, an endoscope cannula support arm 1906, and two
instrument cannula support arms 1908a and 1908b. As shown in FIG.
19A, endoscope cannula support arm 1906 is rigidly mounted on base
1904, although in other implementations it may be pivotally
mounted. The distal end of endoscope cannula support arm 1906 is
curved downwards toward the plane of the base and contains an
endoscope cannula support slot 1910. Detents 1912 in support slot
1910 allow the endoscope cannula to be positioned and held at
various angles.
[0118] FIG. 19A also shows that one instrument cannula support arm
1908a is pivotally mounted on base 1904 at hinge 1914a. An
instrument cannula mount 1916a is at the distal end of cannula
support arm 1908a and holds an illustrative instrument cannula
(e.g., a curved cannula as described above). Cannula mount 1916a
may include one or more mechanical key features to ensure that the
cannula is held at a desired roll orientation, as described above.
FIG. 19A shows the position of support arm 1908a with its
associated cannula in an inserted position.
[0119] FIG. 19A further shows that another instrument cannula
support arm 1908b is pivotally mounted on base 1904 at hinge 1914b,
on a side opposite from support arm 1908a. Support arm 1908b
includes an instrument cannula mount 1916b that is similar to
cannula mount 1916a. FIG. 19A shows the position of support arm
1908b with its associated cannula before the cannula is inserted
though the incision. The cannulas are held by the cannula mounts
1916a,1916b such that the axes of rotation for the hinges
1914a,1914b are at approximately the axes of curvature for the
curved cannulas. Thus, as the support arms rotate at the hinges,
the curved cannulas travel through approximately the same small
area, which is aligned with a single incision or other entry port
into the body. Referring to FIG. 19B, it can be seen that support
arm 1908b has been moved to insert its associated cannula, which
travels in an arc through the incision. In addition, the hinges
1914a,1914b may be oriented such that the two cannulas travel
through slightly different areas in the incision in order to
establish a desired clearance and arrangement among the various
cannulas in the incision.
[0120] An illustrative use of the cannula insertion fixture is with
the single percutaneous/multi-fascial incision, such as one
described above. The surgeon first makes the single percutaneous
incision. Next, the surgeon inserts a dissecting (e.g., sharp)
obturator into an endoscope cannula and couples the endoscope
cannula to the insertion fixture at a desired angle. At this time
the surgeon may insert an endoscope through the endoscope cannula
to observe further insertions, either mounting the endoscope
cannula and endoscope to a robotic manipulator or temporarily
supporting the endoscope by hand. The surgeon then many move the
cannulas along their arc of insertion until they contact the body
wall. Using a dissecting obturator, the surgeon may then insert
each cannula through the fascia. The surgeon may then optionally
remove the dissecting obturators from the cannulas and either leave
the cannulas empty or insert blunt obturators. Then, the surgeon
may continue to move the instrument cannulas to their fully
inserted positions, with their distal ends positioned to appear in
the endoscope's field of view. Once the cannulas are inserted, the
robotic manipulators may be moved into position, and the instrument
cannulas may then be mounted (docked) to their robotic
manipulators. The insertion fixture is then removed, and flexible
shaft instruments are inserted through the cannulas towards the
surgical site under endoscopic vision. This illustrative insertion
procedure is an example of many possible variations for using the
insertion fixture to insert and support any number of cannulas
through various incisions and body openings.
[0121] In some cases, an implementation of an insertion fixture may
be used to support the cannulas while one or more manually operated
instruments are inserted through the cannula(s) and used at the
surgical site.
[0122] In some alternate implementations the insertion fixture may
be simplified to only provide a way of holding the cannulas in a
fixed position during docking to their associated manipulators. For
example, this may be accomplished by first inserting the cannulas,
then applying the fixture to the camera cannula, and then attaching
the fixture to the curved cannulas. Once the inserted cannulas are
coupled to the fixture, the patient side robot and its manipulators
are moved to appropriate positions with reference to the patient.
Then, while the fixture holds the camera cannula and the curved
cannulas in place, each cannula is docked to its associated
manipulator. Generally, the camera cannula is docked first.
[0123] FIG. 19C is a diagrammatic perspective view of a cannula
stabilizing fixture 1930. Fixture 1930 includes a base 1932, two
cannula holders 1934a and 1934b. Arm 1936a couples cannula holder
1934a to base 1932, and arm 1936b couples cannula holder 1934b to
base 1932. Base 1932 is configured to receive an endoscope cannula
in an opening 1938, and two integral spring clips 1940a and 1940b
on either side of opening 1938 securely hold the base on the
endoscope cannula. Each cannula holder 1934a,1934b is configured to
hold an instrument cannula by receiving a key feature similar to
the key feature described above with reference to FIG. 10A. Holes
in the cannula holders receive pins 1036 as shown in FIG. 10A. Arms
1936a,1936b are in one illustrative implementation heavy aluminum
wire covered by silicone tubing, and so the arms may be positioned
as desired. Each arm supports its associated cannula holder and
instrument cannula so that the instrument cannulas are held
stationary with reference to the endoscope cannula when all are
positioned within a single skin incision. Knowledgeable persons
will understand that many variations of this fixture are possible
to hold the various cannulas effectively as a single unit in
position during insertion and during docking to a robotic
manipulator.
[0124] FIGS. 20A-20D are diagrammatic views that illustrate another
way of inserting cannulas into a single incision. FIG. 20A shows
for example an endoscope cannula 2002 and two curved cannulas 2004a
and 2004b. In some instances, an endoscope 2006 may be inserted in
endoscope cannula 2002. The distal ends of the cannulas, and if
applicable the imaging end of an endoscope, are grouped together
inside a cap 2008. In some implementations the cap 2008 may be a
right circular cone made of a material sufficiently rigid to
function as an obturator to penetrate a body wall. In some
implementations, a surgeon first makes an incision, and then cap
2008 with the cannulas grouped behind it is inserted through the
incision. In some instances the cap may be made of a transparent
material that allows the endoscope to image the insertion path in
front of the cap. In some implementations, cap 2008 may be grouped
together with a port feature 2010, such as one described above or
other suitable port feature. Thus in some instances the port
feature may function as one or more of the cannulas for the
endoscope and/or instruments. (As shown, port feature 2010 also
illustrates that insufflation via an insufflation channel 2012 in
any port feature may be provided in some implementations, although
as described above insufflation may be provided in other ways, such
as via one of the cannulas.) A tether 2014 is attached to cap 2008,
and the tether extends to outside the body.
[0125] FIG. 20B shows that the distal ends of the cannulas (or
instruments, as applicable) remain grouped in cap 2008 as it is
inserted farther into the patient. As port feature 2010 remains
secure in body wall 2016, the cannulas (or instruments, as
applicable) slide through it in order to stay within cap 2008. In
some instances the cap is moved farther inwards by pressing on one
or more of the cannulas (or instruments, as applicable). For
example, the endoscope cannula and/or cannula may be mounted on a
robotic camera manipulator, and the manipulator may be used to
insert the cap farther inwards.
[0126] FIG. 20C shows that once the distal ends of the cannulas (or
instruments, as applicable) have reached a desired depth, the
cannulas may be coupled to their associated robotic manipulators
(e.g., cannula 2004a to manipulator 2018a and cannula 2004b to
manipulator 2018b). A surgical instrument may then be inserted
through one of the instrument cannulas (e.g., surgical instrument
2020b through cannula 2004b, as shown) and mounted to an associated
manipulator (e.g., manipulator 2018b). The surgical instrument may
then be used to remove the cap from the distal ends of the cannulas
(or other instruments, as applicable). FIG. 20D shows that the cap
2008 may be placed away from the surgical site inside the patient
during a surgical procedure using the endoscope and both
robotically controlled instruments 2020a and 2020b. Cap 2008 may
optionally incorporate a specimen bag 2022 for specimen retrieval
at the end of the procedure. This specimen bag may optionally
incorporate a draw string to close the bag, and the specimen bag
draw string may optionally be integral with the cap tether 2014.
After surgery is complete and the instruments, cannulas, and port
feature are removed, the cap 2008 (and optional bag) may be removed
by pulling on tether 2014.
Control Aspects
[0127] Control of minimally invasive surgical robotic systems is
known (see e.g., U.S. Pat. No. 5,859,934 (filed Jan. 14,
1997)(disclosing method and apparatus for transforming coordinate
systems in a telemanipulation system), 6,223,100 (filed Mar. 25,
1998) (disclosing apparatus and method for performing computer
enhanced surgery with articulated instrument), 7,087,049 (filed
Jan. 15, 2002)(disclosing repositioning and reorientation of
master/slave relationship in minimally invasive telesurgery), and
7,155,315 (filed Dec. 12, 2005)(disclosing camera referenced
control in a minimally invasive surgical apparatus), and U.S.
Patent Application Publication No. US 2006/0178559 (filed Dec. 27,
2005) (disclosing multi-user medical robotic system for
collaboration or training in minimally invasive surgical
procedures), all of which are incorporated by reference). Control
systems to operate a surgical robotic system may be modified as
described herein for use with curved cannulas and passively
flexible surgical instruments. In one illustrative implementation,
the control system of a da Vinci.RTM. Surgical System is so
modified.
[0128] FIG. 21 is a diagrammatic view of a curved cannula 2102,
which has a proximal end 2104 that is mounted to a robotic
manipulator, a distal end 2106, and a curved section (e.g., 60
degree bend) between the proximal and distal ends. A longitudinal
centerline axis 2110 is defined between the proximal and distal
ends of curved cannula 2102. In addition, an insertion and
withdrawal axis 2112 is defined to include a centerline that
extends along longitudinal axis 2110 in a straight line from the
distal end of the curved cannula. Since the distal section (506c,
FIG. 5) of the passively flexible instrument shaft is relatively
stiff, it moves approximately along insertion and withdrawal axis
2112 as it extends out of the distal end of the curved cannula.
Therefore the control system is configured to assume that the
flexible shaft acts as a straight, rigid shaft having insertion and
withdrawal axis 2112. That is, the instrument's I/O axis is taken
to be the extended straight longitudinal centerline from the distal
end of the curved cannula, and the system determines a virtual
location of the instrument tip to be along the I/O axis 2112. This
instrument I/O movement at the cannula's distal end is illustrated
by double-headed arrow 2114. To prevent excess lateral movement in
the section of the flexible shaft that extends beyond the cannula's
distal end, in one implementation the extension distance is
regulated by the control system software and may depend, e.g., on
the stiffness of the flexible shaft's distal section for the
particular instrument being used. And in one implementation, the
control system will not allow the master manipulator to move the
cannula or instrument until the instrument tip extends beyond the
cannula's distal end.
[0129] The control system is also modified to incorporate kinematic
constraints associated with the curved cannula. The motion of the
instrument tip extending out of the cannula is described as if
produced by a virtual serial kinematic chain of frames of
reference, uniquely described by a set of Denavit-Hartenberg
parameters. For example, boundary conditions at the cannula's
distal end 2106 are defined as the tip position, tip orientation,
and the length along the curved section. Such boundary conditions
are used to define the appropriate Denavit-Hartenberg parameters.
As illustrated in FIG. 21, a reference frame may be defined having
an origin at a location along longitudinal axis 2110 (e.g., at the
cannula's remote center of motion 2116, as shown). One axis 2118 of
such a reference frame may be defined to intersect the extended I/O
axis 2112 at a point 2120. A minimum distance can be determined
between the reference frame's origin and the cannula's distal end
2106. Various different cannula configurations (e.g., length, bend
angle, rotation when mounted on the manipulator, etc.) will have
various associated kinematic constraints. For instrument I/O,
however, the actual path length along the curved section is used
instead of the minimum distance between the remote center of motion
and the instrument's distal tip. Skilled persons will understand
that various methods may be used to describe the kinematic
constraints. For example, an alternate way of solving the problem
is to incorporate the homogenous transformation that describes the
geometry of the curved cannula into the serial kinematics chain
explicitly.
[0130] Further modifications to the control system allow the
surgeon to receive haptic feedback at the master manipulators
(e.g., 122a,122b as shown in FIG. 1B). In various robotic surgical
systems, the surgeon experiences a haptic force from servomotors in
the master manipulators. For example, if the system senses (e.g.,
triggered by an encoder) that a slave side joint limit is reached
or almost reached, then the surgeon experiences a force in the
master that tends to keep the surgeon from moving the master
manipulator in the slave side joint limit direction. As another
example, if the system senses that an external force is applied to
the instrument at the surgical site (e.g., by sensing excess motor
current being used as the system attempts to maintain the
instrument in its commanded position), then the surgeon may
experience a force in the master manipulator that indicates a
direction and magnitude of the external force acting on the slave
side.
[0131] Haptic feedback in the master manipulators is used in one
implementation of a control system used to provide the surgeon an
intuitive control experience while using curved cannulas. For
flexible instruments that do not have a wrist, the control system
provides haptic forces at the master manipulators to prevent the
surgeon from moving the multi-DOF master manipulator with a wrist
motion. That is, master manipulator servomotors attempt to keep the
master manipulator orientation stationary in pitch and yaw
orientations as the surgeon changes the master manipulator
position. This feature is similar to a feature used in current
robotic surgical systems for instruments with straight, rigid
shafts and no wrist. The system senses the instrument type (e.g.,
wristed, non-wristed) and applies the haptic feedback
accordingly.
[0132] Haptic feedback is also used in one implementation to
provide the surgeon a sense of an external force applied to various
points in the instrument kinematic chain. Haptic feed back is
provided to the surgeon for any sensed external force applied to
the manipulator (e.g., as might occur if the manipulator collides
with another manipulator) or to the straight proximal portion of
the curved cannula. Since the cannula is curved, however, the
system cannot provide proper haptic feedback for an external force
applied to the cannula's curved section (e.g., by colliding with
another curved cannula, either inside or outside the endoscope's
field of view), because the system cannot determine the direction
and magnitude of the applied force. In order to minimize such
non-intuitive haptic feedback for this illustrative implementation,
cannula collision is minimized by properly positioning the robotic
manipulators and their associated cannulas, e.g., initially with
the use of a fixture and/or during surgery with the use of a port
feature, as described above. Similarly, the haptic feedback the
system provides to the surgeon that is caused by external force
applied to the portion of the instrument that extends from the
cannula's distal end will not be accurate (unless experienced
directly along the I/O axis). In practice, though, such forces on
the distal ends of the instrument are low compared to the amount of
friction and compliance in the instrument/transmission, and so any
generated haptic feedback is negligible.
[0133] In other implementations, however, force sensors may be used
to provide the surgeon an accurate experience of an external force
applied to either the cannula's curved section or the instrument's
extended distal end. For example, force sensors that use optical
fiber strain sensing are known (see e.g., U.S. Patent Application
Pubs. No. US 2007/0151390 A1 (filed Sep. 29, 2006) (disclosing
force torque sensing for surgical instruments), US 2007/0151391 A1
(filed Oct. 26, 2006)(disclosing modular force sensor), US
2008/0065111 A1 (filed Sep. 29, 2007)(disclosing force sensing for
surgical instruments), US 2009/0157092 A1 (filed Dec. 18, 2007)
(disclosing ribbed force sensor), and US 2009/0192522 A1 (filed
Mar. 30, 2009) (disclosing force sensor temperature compensation),
all of which are incorporated herein by reference). FIG. 22 is a
diagrammatic view of a curved cannula and the distal portion of a
flexible instrument, and it shows that in one illustrative
implementation, one or more force sensing optical fibers
2202a,2202b may be positioned (e.g., four fibers equally spaced
around the outside) on curved cannula 2204 (strain sensing
interrogation and strain determination components for the optical
fibers are omitted for clarity). Similarly, the distal section 2206
of the flexible instrument may incorporate (e.g., routed
internally) one or more strain sensing optical fibers 2208 that
sense bend at a location on, or the shape of the distal section,
and the amount of displacement and the location with reference to
the cannula's distal end may be used to determine the external
force on the extended instrument.
[0134] FIG. 23 is a diagrammatic view of a control system
architecture 2300 for a teleoperated robotic surgical system with
telepresence. As shown in FIG. 23,
[0135] f.sub.b=human forces
[0136] x.sub.b=master position
[0137] e.sub.m,s encoder values (master, slave)
[0138] i.sub.m,s=motor currents (master, slave)=
[0139] .theta..sub.m,x=joint positions (master, slave)
[0140] .tau..sub.m,s=joint torques (master, slave)
[0141] f.sub.m,s=Cartesian forces (master, slave)
[0142] x.sub.m,s=Cartesian positions (master, slave)
[0143] f.sub.e=environmental forces
[0144] x.sub.e=slave position
In one implementation, control system modifications as described
above are done in the "Slave Kinematics" portion 2302 of control
system architecture 2300. Additional details describing control
system architecture 2300 are found, e.g., in the references cited
above. Control system 2300 data processing may be implemented in
electronic data processing unit 142 (FIG. 1C), or it may be
distributed in various processing units throughout the surgical
system.
[0145] Referring to FIGS. 11A and 11B, together with FIG. 1B and
FIG. 4C, it can be seen that in many implementations, the
instrument end effector actuated by the "left" robotic manipulator
appears in the right side of the endoscope's field of view, and the
instrument end effector actuated by the "right" robotic manipulator
appears in the left side of the endoscope's field of view.
Accordingly, to preserve intuitive control of the end effectors as
viewed by a surgeon at the surgeon's console display, the right
master manipulator controls the "left" robotic manipulator, and the
left master manipulator controls the "right" robotic manipulator.
This configuration is opposite the configuration typically used
with straight surgical instruments, in which the robotic
manipulator and its associated instrument are both positioned on
the same side with reference to a vertical division of the
endoscope's field of view. During use with curved cannulas, the
robotic manipulator and its associated instrument are positioned on
opposite sides of the endoscope reference frame. This would not
apply, however, to the use of certain compound curve cannulas, such
as is illustrated by FIG. 13 and associated text.
[0146] Thus various implementations of the control system allow the
surgeon to experience intuitive control of the instrument end
effectors and the resulting telepresence even without the use of an
instrument wrist that provides pitch and yaw movements. Movement of
a master manipulator (e.g., 122a, FIG. 1B) results in a
corresponding movement of either the distal end of the associated
curved cannula (for pitch and yaw movements at the surgical site)
or the instrument end effector (for I/O, roll, and grip (or other
end effector DOF's)). Accordingly, a surgeon's hand motion at a
master control can be reasonably well approximated with a
corresponding slave movement at the surgical site without the use
of a separate wrist mechanism in the instrument. The instrument
tips move in response to master manipulator position changes, not
master manipulator orientation changes. The control system does not
interpret such surgeon wrist-motion orientation changes.
[0147] In some implementations, the control system of a surgical
robotic system may be configured to automatically switch between
the use of straight cannulas with associated straight shaft
instruments, and the use of curved cannulas with associated
flexible shaft instruments. For example, the system may sense that
both a curved cannula and a flexible shaft instrument are mounted
on a manipulator, as described above with reference to FIG. 6 and
FIG. 10, and so switch to a control mode associated with the curved
cannula and the flexible instrument. If however, the system senses
a straight cannula and flexible instrument mounted on the
manipulator, then this sensing may trigger an illegal state, and
the system will not operate.
[0148] In some implementations for surgical robotic systems with
multiple robotic manipulators, the control software can allow the
surgeon to use a mix of curved cannulas of various different
shapes, flexible shaft instruments of various different lengths,
together with straight cannulas and rigid straight-shaft
instruments. The tip motion of all such instruments will appear
alike, and so the surgeon will experience intuitive control because
of the automatic handling of the cannula kinematic constraints as
described above.
[0149] In one aspect, a surgical system comprises: a robotic
manipulator; a rigid cannula, wherein the cannula comprises a
proximal end, a distal end, and a curved section between the
proximal and distal ends, wherein the proximal end of the cannula
is mounted to the robotic manipulator, and wherein the robotic
manipulator is configured to move the cannula around a remote
center of motion in at least a pitch or a yaw degree of freedom;
and a surgical instrument comprising a flexible shaft and an end
effector coupled to a distal end of the flexible shaft, wherein a
first portion of the flexible shaft extends through the curved
section of the cannula, and wherein a second portion of the
flexible shaft extends beyond the distal end of the cannula.
[0150] In another aspect, a surgical system comprises: a first
robotic manipulator, a first curved cannula coupled to the first
robotic manipulator, and a first surgical instrument comprising a
flexible shaft that extends through the first curved cannula,
wherein the first robotic manipulator is configured to move the
first cannula around a first center of motion; a second robotic
manipulator, a second curved cannula coupled to the second robotic
manipulator, and a second surgical instrument comprising a flexible
shaft that extends through the second curved cannula, wherein the
second robotic manipulator is configured to move the second cannula
around a second center of motion; wherein the first and second
centers of motion are positioned proximate to one another; and
wherein distal ends of the first and second curved cannulas are
oriented to direct the distal ends of the first and second surgical
instruments towards a surgical site.
[0151] In another aspect, a cannula comprises: a rigid tube having
a proximal straight section and a curved section adjacent the
proximal straight section; and a robotic manipulator mount coupled
to the proximal end of the tube.
[0152] In another aspect, a surgical instrument comprises: a
passively flexible shaft comprising a middle section and a distal
section; and a surgical end effector coupled to the distal section
of the flexible shaft; wherein a stiffness of the distal section of
the passively flexible shaft is larger than a stiffness of the
middle section of the passively flexible shaft.
[0153] In another aspect, a surgical port feature comprises: a port
feature body comprising a top surface and a bottom surface; a first
surgical instrument channel that extends in a first direction
across a vertical midsection of the port feature body from the top
surface to the bottom surface; and a second surgical instrument
channel that extends in a second direction, opposite the first
direction, across the vertical midsection of the port feature body
from the top surface to the bottom surface.
[0154] In another aspect, a surgical port feature comprises: a
funnel portion; a tongue; a waist portion between the funnel
portion and the tongue; and at least two surgical instrument
channels defined in the waist section.
[0155] In another aspect, a cannula mounting fixture comprises: a
first arm comprising an endoscope cannula mounting bracket; and a
second arm comprising a surgical instrument cannula mounting
bracket; wherein the endoscope cannula mounting bracket and the
surgical instrument mounting bracket are each oriented to hold a
cannula at the same opening into a patient's body.
[0156] In another aspect, a cannula mounting fixture comprises: a
pointed cap comprising an interior; wherein the interior of the cap
is configured to removably hold a distal end of an endoscope and a
distal end of a surgical instrument cannula.
[0157] In another aspect, a robotic surgical system comprises: a
master manipulator; a robotic slave manipulator; a curved cannula
coupled to the robotic slave manipulator; a passively flexible
instrument shaft that extends past a distal end of the curved
cannula; and a control system; wherein a straight line instrument
insertion and withdrawal axis is defined extending from a
longitudinal center axis of the curved cannula at a distal end of
the curved cannula; and wherein in response to a movement of the
master manipulator, the control system commands the robotic
manipulator to move the distal end of the curved cannula around a
remote center of motion as if the instrument were positioned
straight along the instrument insertion and withdrawal axis.
* * * * *