U.S. patent application number 14/206821 was filed with the patent office on 2014-10-02 for surgical instrument shaft.
This patent application is currently assigned to INTUITIVE SURGICAL OPERATIONS, INC.. The applicant listed for this patent is INTUITIVE SURGICAL OPERATIONS, INC.. Invention is credited to Samuel T. CREWS, Nicole KERNBAUM, Harsukhdeep Singh RATIA.
Application Number | 20140296869 14/206821 |
Document ID | / |
Family ID | 51621563 |
Filed Date | 2014-10-02 |
United States Patent
Application |
20140296869 |
Kind Code |
A1 |
KERNBAUM; Nicole ; et
al. |
October 2, 2014 |
SURGICAL INSTRUMENT SHAFT
Abstract
A surgical instrument may include a shaft, a force transmission
mechanism, and an end effector. The shaft may have a proximal end
and a distal end. The force transmission mechanism may be coupled
to the proximal end of the shaft. The end effector may be coupled
to the distal end of the shaft. The shaft may include a body having
an outer surface and an inner surface. The inner surface may
surround a lumen configured to receive a drive member that extends
through the lumen. The outer surface of the body may form an outer
surface of the shaft. The body may be made of a single material
from the inner surface of the body to the outer surface of the
body.
Inventors: |
KERNBAUM; Nicole;
(Sunnyvale, CA) ; CREWS; Samuel T.; (Palomar Park,
CA) ; RATIA; Harsukhdeep Singh; (Fostercity,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INTUITIVE SURGICAL OPERATIONS, INC. |
Sunnyvale |
CA |
US |
|
|
Assignee: |
INTUITIVE SURGICAL OPERATIONS,
INC.
Sunnyvale
CA
|
Family ID: |
51621563 |
Appl. No.: |
14/206821 |
Filed: |
March 12, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61781679 |
Mar 14, 2013 |
|
|
|
Current U.S.
Class: |
606/130 ;
264/209.1 |
Current CPC
Class: |
A61B 34/30 20160201;
B29C 48/09 20190201; A61B 2217/007 20130101; A61B 2017/2901
20130101; A61B 34/37 20160201; A61B 34/71 20160201; A61B 34/35
20160201; A61B 1/05 20130101; B29C 48/21 20190201; A61B 17/2841
20130101 |
Class at
Publication: |
606/130 ;
264/209.1 |
International
Class: |
A61B 19/00 20060101
A61B019/00; B29D 23/00 20060101 B29D023/00 |
Claims
1. A surgical instrument, comprising: a shaft having a proximal end
and a distal end; a force transmission mechanism coupled to the
proximal end of the shaft; and an end effector coupled to the
distal end of the shaft; wherein the shaft includes a body having
an outer surface and an inner surface, the inner surface
surrounding a lumen configured to receive a drive member that
extends through the lumen; wherein the outer surface of the body
forms an outer surface of the shaft; wherein the body is made of a
single material from the inner surface of the body to the outer
surface of the body.
2. The instrument of claim 1, wherein the body comprises an inner
tube and an outer tube.
3. The instrument of claim 2, wherein the body further comprises a
plurality of ribs connecting the inner tube and the outer tube.
4. The instrument of claim 3, wherein the body further comprises a
second lumen and a conduit extending through the second lumen.
5. The instrument of claim 2, wherein the inner tube and the outer
tube are in contact with one another and are configured to slide
relative to one another along an axial direction of the shaft.
6. The instrument of claim 2, wherein the body is continuously
solid between the outer surface and inner surface of the body.
7. The instrument of claim 2, wherein the outer surface of the body
is exposed to a surrounding environment.
8. The instrument of claim 2, wherein an inner surface of the outer
tube and an outer surface of the inner tube have substantially the
same radius of curvature.
9. The instrument of claim 2, further comprising a sheath located
on the outer surface of the shaft.
10. The instrument of claim 1, wherein the body consists of a
single tube.
11. The instrument of claim 1, wherein the single tube is a solid
tube between the inner surface and the outer surface.
12. The instrument of claim 1, further comprising a sheath located
on the outer surface of the shaft.
13. The instrument of claim 1, wherein the outer surface of the
body has a substantially circular cross-section.
14. The instrument of claim 1, further comprising a plurality of
projections on the outer surface.
15. The instrument of claim 1, further comprising the drive member,
which extends through the lumen from the force transmission
mechanism to the end effector, wherein the inner surface of the
body contacts the drive member.
16. The instrument of claim 1, wherein the lumen formed by the
inner surface of the body has a diameter ranging from about 0.030''
to about 0.050''.
17. The instrument of claim 1, wherein the instrument is a surgical
instrument for a teleoperated surgical system.
18. A surgical instrument, comprising: a shaft having a proximal
end and a distal end; a force transmission mechanism coupled to the
proximal end of the shaft; and an end effector coupled to the
distal end of the shaft; wherein the shaft includes a body having
an outer surface that forms an outer surface of the shaft and an
inner surface that defines a lumen that a drive member extends
through; wherein the body has a single piece construction.
19. A method of manufacturing a shaft for a surgical instrument,
comprising: extruding a material to form a body of a shaft, wherein
the body has an outer surface and an inner surface that forms a
lumen configured to receive a drive member that extends through the
lumen; wherein the outer surface of the body forms an outer surface
of the shaft; and wherein the body is made of a single material
from the inner surface of the body to the outer surface of the
body.
20. The method of claim 19, wherein the body is continuously solid
from the inner surface of the body to the outer surface of the
body.
21. The method of claim 19, wherein the body comprises an inner
tube and an outer tube.
22. The method of claim 21, wherein the body further comprises a
plurality of ribs connecting the inner tube and the outer tube.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/781,679, filed on Mar. 14, 2013, which is
incorporated by reference herein in its entirety.
TECHNICAL FIELD
[0002] Aspects of the present disclosure relate to a surgical
instrument, for example for use with a teleoperated (robotic)
surgical system. In particular, aspects of the present disclosure
relate to the shaft construction of such a surgical instrument.
INTRODUCTION
[0003] Some minimally invasive surgical techniques are performed
remotely through the use of teleoperated (robotically-controlled)
surgical instruments (which may also be referred to as tools). In
teleoperated surgical systems, surgeons manipulate input devices at
a surgeon console, and those inputs are passed to a patient side
cart that interfaces with one or more teleoperated surgical
instruments. Based on the surgeon's inputs at the surgeon console,
the one or more surgical instruments are actuated at the patient
side cart to operate on the patient, thereby creating a
master-slave control relationship between the surgeon console and
the surgical instrument(s) at the patient side cart.
[0004] Teleoperated surgical systems may have multiple arms to
which teleoperated surgical instruments may be coupled. Because the
surgical instruments may be used within a relatively small space
inside of a patient during a surgical procedure, and because it is
desirable to minimize the size of incisions and ports through which
a surgical instrument may be passed to access the surgical site,
and to otherwise minimize the invasiveness of a surgical procedure,
components of a surgical instrument can be relatively small in
size. Although components of a surgical instrument may be
relatively small, it remains desirable that the components exhibit
properties that allow them to perform various functions that may be
required during a surgical procedure. To some degree, the issues of
size and functionality may provide countervailing considerations
when designing and manufacturing a surgical instrument. In view of
these considerations, it may be desirable to provide a surgical
instrument that has a robust design and provides mechanical
properties that support the functions for which a surgical
instrument may be used. It also may be desirable to provide such a
surgical instrument that facilitates manufacture.
SUMMARY
[0005] Exemplary embodiments of the present disclosure may solve
one or more of the above-mentioned problems and/or may demonstrate
one or more of the above-mentioned desirable features. Other
features and/or advantages may become apparent from the description
that follows.
[0006] In accordance with at least one exemplary embodiment, a
surgical instrument comprises a shaft, a force transmission
mechanism, and an end effector. The shaft may have a proximal end
and a distal end. The force transmission mechanism may be coupled
to the proximal end of the shaft. The end effector may be coupled
to the distal end of the shaft. The shaft may include a body having
an outer surface and an inner surface. The inner surface may
surround a lumen configured to receive a drive member that extends
through the lumen. The outer surface of the body may form an outer
surface of the shaft. The body may be made of a single material
from the inner surface of the body to the outer surface of the
body.
[0007] In accordance with at least one exemplary embodiment, a
surgical instrument comprises a shaft, a force transmission
mechanism, and an end effector. The shaft may have a proximal end
and a distal end. The force transmission mechanism may be coupled
to the proximal end of the shaft. The end effector may be coupled
to the distal end of the shaft. The shaft may include a body having
an outer surface that forms an outer surface of the shaft and an
inner surface that defines a lumen that a drive member extends
through. The body may have a single piece construction.
[0008] In accordance with at least one exemplary embodiment, a
method of manufacturing a shaft for a surgical instrument comprises
extruding a material to form a body of a shaft. The body may have
an outer surface and an inner surface that forms a lumen configured
to receive a drive member that extends through the lumen. The outer
surface of the body may form an outer surface of the shaft. The
body may be made of a single material from the inner surface of the
body to the outer surface of the body.
[0009] Additional objects, features, and/or advantages will be set
forth in part in the description which follows, and in part will be
obvious from the description, or may be learned by practice of the
present disclosure and/or claims. At least some of these objects
and advantages may be realized and attained by the elements and
combinations particularly pointed out in the appended claims.
[0010] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the claims; rather
the claims should be entitled to their full breadth of scope,
including equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present disclosure can be understood from the following
detailed description, either alone or together with the
accompanying drawings. The drawings are included to provide a
further understanding of the present disclosure, and are
incorporated in and constitute a part of this specification. The
drawings illustrate one or more exemplary embodiments of the
present teachings and together with the description serve to
explain certain principles and operation.
[0012] FIG. 1 is a schematic view of an exemplary embodiment of a
portion of a manipulator supporting a curved cannula and a surgical
instrument.
[0013] FIG. 2 is a top schematic view of an exemplary embodiment of
a surgical instrument including a force transmission mechanism.
[0014] FIG. 3 is an exploded view of an exemplary embodiment of a
shaft of a surgical instrument.
[0015] FIG. 4 is a cross-sectional view of the shaft of FIG. 3
taken along line 4-4.
[0016] FIG. 5 is a cross-sectional view of an exemplary embodiment
of a shaft of a surgical instrument.
[0017] FIG. 6 is a cross-sectional view of another exemplary
embodiment of a shaft of a surgical instrument.
[0018] FIG. 7 is a cross-sectional view of yet another exemplary
embodiment of a shaft of a surgical instrument.
[0019] FIG. 8 is a cross-sectional view of an exemplary embodiment
of a sheathed shaft of a surgical instrument.
[0020] FIG. 9 is a cross-sectional view of another exemplary
embodiment of a sheathed shaft of a surgical instrument.
[0021] FIG. 10 is a cross-sectional view of yet another exemplary
embodiment of a sheathed shaft of a surgical instrument.
[0022] FIG. 11 is a schematic side view of a surgical instrument
inserted to a maximum distance within a curved cannula, according
to an exemplary embodiment.
[0023] FIG. 12 is a schematic side view of a surgical instrument
inserted to a minimum distance within a curved cannula, according
to an exemplary embodiment.
[0024] FIG. 13 is a cross-sectional view of another exemplary
embodiment of a shaft of a surgical instrument.
DETAILED DESCRIPTION
[0025] Exemplary embodiments discussed herein regard a surgical
instrument for a teleoperated surgical system. The surgical
instrument may facilitate manufacture, while providing a robust
design with properties that support the functions for which the
instrument is intended. In various exemplary embodiments, for
example, a shaft of the surgical instrument may be configured to
have a substantially uniform stiffness. Further, various exemplary
embodiments enable substantial consistency in the manufacture of
one shaft to the next.
[0026] This description and the accompanying drawings that
illustrate exemplary embodiments should not be taken as limiting.
Various mechanical, compositional, structural, electrical, and
operational changes may be made without departing from the scope of
this description and the invention as claimed, including
equivalents. In some instances, well-known structures and
techniques have not been shown or described in detail so as not to
obscure the disclosure. Like numbers in two or more figures
represent the same or similar elements. Furthermore, elements and
their associated features that are 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.
[0027] For the purposes of this specification and appended claims,
unless otherwise indicated, all numbers expressing quantities,
percentages, or proportions, and other numerical values used in the
specification and claims, are to be understood as being modified in
all instances by the term "about," to the extent they are not
already so modified. Accordingly, unless indicated to the contrary,
the numerical parameters set forth in the following specification
and attached claims are approximations that may vary depending upon
the desired properties sought to be obtained. At the very least,
and not as an attempt to limit the application of the doctrine of
equivalents to the scope of the claims, each numerical parameter
should at least be construed in light of the number of reported
significant digits and by applying ordinary rounding
techniques.
[0028] It is noted that, as used in this specification and the
appended claims, the singular forms "a," "an," and "the," and any
singular use of any word, include plural referents unless expressly
and unequivocally limited to one referent. As used herein, the term
"include" and its grammatical variants are intended to be
non-limiting, such that recitation of items in a list is not to the
exclusion of other like items that can be substituted or added to
the listed items.
[0029] Teleoperated surgery generally involves the use of a
manipulator that has multiple manipulator arms. One or more of the
manipulator arms often support a teleoperated surgical instrument
that is ultimately placed in a master-slave relationship with
master controllers at a surgeon console, such that inputs by a
surgeon at the surgeon console are provided as signals to control
movement of the surgical instruments. One or more of the
manipulator arms typically also is used to support a surgical image
capture device, such as a camera endoscope (which may be any of a
variety of structures such as a laparoscope, an arthroscope, a
hysteroscope, or the like), or, optionally, some other imaging
modality (such as ultrasound, fluoroscopy, magnetic resonance
imaging, or the like) so as to provide the surgeon with a view of
the remote surgical site. Typically, at least three manipulator
arms will respectively support two surgical tools (corresponding to
the two hands of a surgeon) and an image capture device. Reference
is made to U.S. application Ser. No. 12/618,583, entitled "Curved
Cannula Surgical System," filed on Nov. 13, 2009 and published as
U.S. Pub. No. US 2011/0071542 on Mar. 24, 2011, now issued as U.S.
Pat. No. 8,545,515, which is hereby incorporated by reference in
its entirety, for examples of a teleoperated surgical system.
[0030] Turning to FIG. 1, a schematic view of a portion of a
patient side manipulator (or "PSM") that supports and moves a
combination of a curved cannula and a passively flexible surgical
instrument is shown, according to an exemplary embodiment. As
depicted in FIG. 1, a surgical instrument 110 includes a force
transmission mechanism 112, a flexible shaft 114, and an end
effector 116. According to an exemplary embodiment, shaft 114 of
instrument 110 may be passively flexible. Instrument 110 is mounted
on an instrument carriage assembly 102 of manipulator 100.
Interface discs 104 couple actuation forces from servo actuators in
manipulator 100 to move instrument 110 components.
[0031] According to an exemplary embodiment, end effector 116
operates with a single degree of freedom (DOF) (e.g., closing
jaws). According to an exemplary embodiment, instrument 110 may
include a wrist structure (not shown) 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). An instrument 110, as shown in
the exemplary embodiment of FIG. 1, lacking a wrist may be referred
to as a non-wristed instrument. Omitting a wrist, for example, can
simplify the number of actuation force interfaces between
manipulator 100 and instrument 110; such omission can also reduce
the number of force transmission elements (and hence, instrument
complexity and dimensions) that would be utilized between the
proximal force transmission mechanism 112 and the distally actuated
end effector 116 in order to actuate a wrist structure.
[0032] FIG. 1 further shows a curved cannula 120, which has a
proximal end 122, a distal end 124, and a central channel 126 that
extends between proximal end 122 and distal end 124. According to
an exemplary embodiment, curved cannula 120 is a rigid, single
piece cannula. Curved cannula 120 may include one or more straight
sections 121 and one or more curved sections 123, according to an
exemplary embodiment. According to an exemplary embodiment, curved
cannula 120 may be curved (not shown) from proximal end 122 to
distal end 124. A curved section 125 of a curved cannula 120 may
have a curvature with an angle between ends of section 125, for
example, ranging from about 40.degree. to about 65.degree.. In
another example, curved section 125 may have a curvature ranging
from about 45.degree. or about 60.degree.. Curved section 123 may
have a centerline radius 127, shown in the exemplary embodiment of
FIG. 1, ranging from about 4.50 inches to about 5.50 inches, for
example.
[0033] As depicted in the exemplary embodiment of FIG. 1, proximal
end 122 of curved cannula 120 is mounted on a cannula mount 106 of
manipulator 100. During use, flexible shaft 114 of instrument 110
extends through the central channel 126 of curved cannula 120 so
that a distal portion of flexible shaft 114 and end effector 116
extend beyond distal end 124 of cannula 120 in order to reach a
surgical site 130. Constraints of manipulator 100 (whether
mechanical and/or preprogrammed software constraints in the control
system for manipulator 100) cause instrument 110 and curved cannula
120 to move in pitch and yaw around remote center of motion 140
located along cannula 120, which may be located at an incision or
port in a patient's body wall. The I/O actuation of manipulator
100, provided by carriage 102, inserts and withdraws instrument 110
through cannula 120 to move end effector 116 in and out.
[0034] FIG. 2 depicts a top view of an exemplary embodiment of a
surgical instrument 200 for a teleoperated surgical system.
Surgical instrument 110 of FIG. 1 may be configured according to
the exemplary embodiment of FIG. 2. Surgical instrument 200 may
include a force transmission mechanism 210, a shaft 222 connected
to force transmission mechanism 210 at a proximal end 223 of shaft
222, and an end effector 220 connected to a distal end 224 of shaft
222. Surgical instrument 200 may include one or more members to
translate force between force transmission mechanism 210 and end
effector 220. For instance, one or more drive member(s) 226 may
connect force transmission mechanism 210 to end effector 220 to
provide actuation forces to end effector 220, such as by extending
through an interior of shaft 222.
[0035] By utilizing drive member(s) 226, force transmission
mechanism 210 may actuate end effector 220, for example, to control
a wrist structure (if any) of instrument 200 and/or to control a
jaw of end effector 220 (or other moveable part). Further, because
end effector 220 may be fixed to shaft 222, force translated from
force translation mechanism 210 to end effector 220 may in turn be
translated to shaft 222, such as when force translation mechanism
210 actuates end effector 220 and shaft 222 in a rolling motion.
Drive member(s) 226 may be in the form of tension elements, such as
when force transmission mechanism 210 is a pull-pull mechanism, as
described in U.S. Pub. No. US 2011/0071542, or one or more drive
element rods, such as when force transmission mechanism 210 is a
push-pull mechanism, as described in U.S. Pub. No. US
2011/0071542.
[0036] Force transmission mechanism 210 may include one or more
components to engage with a patient side cart of a teleoperated
surgical system to translate a force provided by patient side cart
to surgical instrument 200. According to an exemplary embodiment,
force transmission mechanism 210 may include one or more interface
disks 212, 214 that engage with a manipulator of a patient side
cart, as discussed above in regard to the exemplary embodiment of
FIG. 1. Thus, interface disks 212, 214 utilize actuation forces
from a manipulator to actuate instrument 200. For instance, first
disk 212 may be configured to provide a rolling motion to shaft 222
and provide a roll DOF for end effector 220, while second disk 214
may operate a jaw mechanism of end effector 220 to open and close.
However, these particular actuation schemes/controls are exemplary
only and other configurations are envisioned, depending on the type
of instrument and motions for use of such instruments.
[0037] As discussed above, a shaft of a surgical instrument may be
flexible. Flexibility, for example, may assist with inserting the
instrument through a curved cannula. However, the instrument shaft
may also be required to support an end effector when the distal end
of the shaft and the end effector are extended beyond a distal end
of the curved cannula. For instance, the shaft 114 of instrument
110 shown in the exemplary embodiment of FIG. 1 may be flexible to
permit instrument 110 to be inserted and withdrawn through curved
cannula 120 but also be sufficiently stiff to provide effective
surgical action at a surgical site 130. As a result, flexible shaft
114 of instrument 110 may be extended through the central channel
126 of curved cannula 120 so that a distal portion of flexible
shaft 114 and end effector 116 extend beyond the distal end 124 of
cannula 120 to reach surgical site 130. In view of these
considerations, a shaft of a surgical instrument may include
structures to affect the flexibility and stiffness of the
shaft.
[0038] Some shaft configurations utilize multiple parts to provide
a shaft that is flexible, such as to facilitate passing an
instrument through a curved cannula, but also stiff, such as to
support an end effector. Further, the shaft may include paths to
route cabling and other instrument control mechanisms from a
proximal end to a distal end. Turning to FIG. 3, an exploded view
of an exemplary embodiment of a shaft 300 for a surgical instrument
is shown. Shaft 300 may include an outer tube 302 and a channeled
insert 306 sized to be contained inside of the outer tube 302.
Turning to FIG. 4, which is a cross-sectional view along line 4-4
in FIG. 3, channeled insert 306 may include a lumen 307 for a drive
member 310 connecting a force transmission mechanism to an end
effector of the surgical instrument, as discussed in the exemplary
embodiments of FIGS. 1 and 2. For instance, drive member 310 may be
a drive element rod, such as when the force transmission mechanism
is a push-pull mechanism to actuate the end effector. Channeled
insert 306 may be provided within outer tube 302 to support and
locate drive member 310 within outer tube 302. According to an
exemplary embodiment, outer surface 305 of first tube 302 may form
an outer surface of the shaft.
[0039] Outer tube 302 may be constructed to provide a degree of
stiffness and flexibility to shaft 300. For instance, outer tube
302 may be made of a relatively durable and stiff material that is
relatively flexible. For example, outer tube 302 may comprise
polyether ether ketone (PEEK) or other similar materials used in
the art for the tubes of surgical instrument shafts. The insert 306
may be constructed so that insert 306 is more compliant and
flexible than outer tube 302. For instance, it may be desirable for
insert 306 to be more compliant and flexible than outer tube 302 to
facilitate insertion of insert 306 within outer tube 302. To
accomplish this, insert 306 may be made of a material that is more
compliant than the material of outer tube 302. For example, insert
306 may comprise fluorinated ethylene propylene (FEP).
[0040] Outer tube 302 and insert 306 may be sized and arranged
relative to one another to provide lumens within the instrument
shaft 300 between outer tube 302 and insert 306. As shown in the
exemplary embodiment of FIG. 4, outer tube 302 and insert 306 may
be configured to provide one or more lumens 301 between outer tube
302 and insert 306. Lumen 301 may be used, for instance, as a
passage for cleaning fluid to flush an interior of shaft 300 during
a procedure to clean a surgical instrument. According to an
exemplary embodiment, shaft 300 may include one or more conduits
312 to provide a flux to an end effector of a surgical instrument.
In such embodiments, tube 302 and insert 306 may provide one or
more lumens 303 for the one or more conduits 312. A flux may be,
for example, a form of energy, suction, irrigation fluid, or other
flux used with surgical instruments. For instance, if a surgical
instrument is an electrosurgical instrument, such as for
cauterization procedure, the one or more conduits 312 may be wires
to provide electrical energy to an end effector.
[0041] Because insert 306 is relatively compliant and flexible,
particularly in comparison to outer tube 302, insert 306 may be
altered to increase the stiffness of insert 306. For instance,
insert 306 may include one or more structures to increase the
stiffness of insert 306. As shown in the exemplary embodiment of
FIGS. 3 and 4, one or more wires 308 may be inserted within lumens
309 of insert 306 to increase the stiffness of insert 306.
According to an exemplary embodiment, wires 308 may be made of a
material having a higher stiffness than the material of insert 306.
For example, wires 308 may be made of a metal. In another example,
wires 308 may be made of a stainless steel, such as type 304
stainless steel. Stiffening wires may extend the length of shaft
300, such as from proximal end 223 to distal end 224, as shown in
the exemplary embodiment of FIG. 2. As shown in the exemplary
embodiment of FIGS. 3 and 4, shaft 300 may include four stiffening
wires 308, although shaft 300 is not limited to this number of
wires 308 and the number and type of stiffening structures may be
selected as desired.
[0042] According to an exemplary embodiment, shaft 300 may include
a sheath 304 located on an outer surface of first tube 302. Sheath
304 may be provided to affect the coefficient of friction of shaft
300, such as by providing a smooth surface that facilitates
insertion of an instrument within a cannula. In various exemplary
embodiments, sheath 304 may be made of ethylene tetrafluoroethylene
(ETFE) or other sheath materials that are used in the art.
[0043] A surgical instrument shaft 300 having a construction shown
in the exemplary embodiment of FIGS. 3 and 4 can be both compliant
enough to be advanced and withdrawn through a curved cannula, while
being stiff enough to support the functions of an end effector
connected to a distal end of shaft 300. However, shaft 300 includes
numerous components, which can be made of different materials. In
addition, manufacture of shaft 300 may require numerous steps. As a
result, shaft 300 may be relatively costly to manufacture due to
the complexity of its production process and the different
materials utilized.
[0044] Another consideration for the shaft 300 of the exemplary
embodiment of FIGS. 3 and 4 is the ease of controlling the
properties of shaft 300. Manufacturing processes and tolerances may
make manufacture of shaft 300 relatively difficult, particularly
when shaft 300 includes multiple pieces, such as outer tube 302,
insert 306, and wires 308. For instance, manufacturing processes
and tolerances of the dimensions of shaft components in both a
radial direction and an axial direction along the length of the
shaft may affect the overall stiffness of the shaft.
[0045] In view of these considerations, various exemplary
embodiments contemplate a surgical instrument having a shaft that
is relatively easy and inexpensive to manufacture and exhibits an
overall stiffness that enhances control of the instrument during
use and is substantially uniform from one shaft to another. Various
exemplary embodiments may provide a surgical instrument that
exhibits enhanced motion control and minimal unintended movement of
an end effector, such as in directions 230, 232 shown in the
exemplary embodiment of FIG. 2, during the use of the end effector
of the instrument.
[0046] Turning to FIG. 5, an exemplary embodiment of a surgical
instrument shaft 400 is shown in cross-section. Shaft 400 may be
used for an instrument discussed in the exemplary embodiments of
FIGS. 1 and 2. As shown in FIG. 5, shaft 400 may include an outer
tube 402 and an inner tube 404. According to an exemplary
embodiment, shaft 400 may have a body that is provided by inner
tube 404 and outer tube 402. For instance, the body of shaft 400
may extend between an inner surface 409 of inner tube 404 to an
outer surface 401 of outer tube 402. Thus, inner surface 409 may
form an inner surface of the body of shaft 400 and outer surface
401 may form an outer surface of the body of shaft 400. According
to an exemplary embodiment, each of inner tube 404 and outer tube
402 may be made by extruding a material to form a hollow cylinder,
as shown in FIG. 5.
[0047] According to an exemplary embodiment, inner tube 404 may
have a wall thickness that is substantially the same as the wall
thickness of outer tube 402. According to another example
embodiment, inner tube 404 and outer tube 402 have different wall
thicknesses. For instance, inner tube 404 may have a greater wall
thickness or a smaller wall thickness than outer tube 402.
[0048] Outer tube 402 and inner tube 404 may each have a form of a
hollow cylinder, according to an exemplary embodiment. As shown in
the exemplary embodiment of FIG. 5, outer tube 402 may be
continuously solid between its inner surface 403 and its outer
surface 401 and thus lack any lumen (i.e., be lumenless).
Similarly, inner tube may be solid and lack any lumen between its
outer surface 405 and its inner surface 409, as shown in the
exemplary embodiment of FIG. 5.
[0049] Inner tube 404 may include a lumen 407 that is configured to
receive a drive member 406 connecting a force transmission
mechanism to an end effector of the surgical instrument, as
discussed in the exemplary embodiments of FIGS. 1 and 2. An inner
surface 409 of inner tube 404 that forms lumen 407 can be in
contact with drive member 406, according to an exemplary
embodiment. According to an exemplary embodiment, lumen 407 may
have a diameter ranging from about 0.030'' to about 0.050''.
According to another exemplary embodiment, lumen 407 may have a
diameter ranging from about 0.035'' to about 0.045''. According to
an exemplary embodiment, a diameter of shaft 400 may be about 5 to
about 5.5 times the diameter of lumen 407.
[0050] According to an exemplary embodiment, an outer surface 401
of outer tube 402 may form an outer surface of shaft 400. For
instance, outer surface 401 may be uncovered or otherwise exposed
to a surrounding environment. As shown in the exemplary embodiment
of FIG. 5, outer surface 401 may have a substantially circular
cross-section. According to an exemplary embodiment, shaft 400 may
consist of drive member 406, inner tube 404, and outer tube
402.
[0051] Tubes 402, 404 may be provided, for example, as hollow
cylinders, as shown in the exemplary embodiment of FIG. 5, that
have similar shapes and are concentric. According to an exemplary
embodiment, an inner surface 403 of outer tube 402 and an outer
surface 405 of inner tube 404 may have substantially the same
radius of curvature. Although inner tube 404 and outer tube 402 are
in contact with one another, inner tube 404 and outer tube 402 may
be configured to move relative to one another to facilitate bending
of shaft 400. For instance, inner tube 404 and outer tube 402 may
be configured to slide relative to one another, such as along the
proximal-distal direction shown in the exemplary embodiment of FIG.
2, when shaft 400 is bent.
[0052] According to an exemplary embodiment, tubes 402, 404 may
have similar or substantially the same stiffness values. As a
result, inner tube 404 may function as a stiffening tube for outer
tube 402 and may provide a sufficient stiffness to the shaft so as
to enable support of the end effector as discussed above. Utilizing
the inner tube 404 as a mechanism for stiffening the outer tube 402
can reduce the number of other additional stiffening members that
may be used and the overall number of components of the surgical
instrument shaft.
[0053] According to an exemplary embodiment, inner tube 404 and
outer tube 402 may comprise the same material, such as, for
example, PEEK. Use of the same or similar materials that provide
sufficient stiffness properties for both the inner tube 402 and
outer tube 404 may further provide the shaft with an overall
stiffness that is substantially uniform from one shaft to another
during a manufacturing process.
[0054] Turning to FIG. 6, an exemplary embodiment of a shaft 500 of
a surgical instrument is shown in cross section. Shaft 500 may
include an outer tube 502 and an inner tube 504. Inner tube 504 may
include a lumen 507 for a drive member 506 connecting a force
transmission mechanism to an end effector of the surgical
instrument, as discussed in the exemplary embodiments of FIGS. 1
and 2. An inner surface 509 of inner tube 504 that defines lumen
507 may be in contact with drive member 506, according to an
exemplary embodiment.
[0055] Outer tube 502 and inner tube 504 may be connected by a
plurality of ribs 510. As shown in the exemplary embodiment of FIG.
6, ribs 510, inner tube 504, and outer tube 502 may define one or
more lumens 508. Lumens 508 may be used, for example, for flushing
fluid in a cleaning operation. In another example, lumens 508 may
serve as passages, such as for one or more conduits 512 to provide
a flux to an end effector of a surgical instrument. According to an
exemplary embodiment, an outer surface 501 of outer tube 502 may
define an outer surface of shaft 500. Further, according to an
exemplary embodiment, shaft 500 may consist of inner tube 504,
outer tube 502, at least one rib 510, at least one lumen 508, and
drive member 506. According to another exemplary embodiment, shaft
500 may include inner tube 504, outer tube 502, at least one rib
510, at least one lumen 508, at least one conduit 512, and drive
member 506.
[0056] A body of shaft 500 may be formed by inner tube 504, outer
tube 502, and ribs 510. To provide an instrument shaft that
advantageously includes fewer components, is less difficult to
manufacture, and is less costly to manufacture, instrument shaft
500 (not including drive member 506) may have a single piece
construction. Thus, the body of shaft 500 formed by inner tube 504,
outer tube 502, and ribs 510 may be formed as a single piece.
According to an exemplary embodiment, the body formed by inner tube
504, outer tube 502, and ribs 510 may be defined by a single piece
formed in an extrusion process. According to an exemplary
embodiment, the body formed by inner tube 504, outer tube 502, and
ribs 510 may be made of the same material. For instance, the body
of shaft 500 may be formed from a single material between inner
surface 509 and outer surface 501. Thus, inner surface 509 may form
an inner surface of the body of shaft 500 and outer surface 501 may
form an outer surface of the body of shaft 500. According to an
exemplary embodiment, an outer surface 501 of outer tube 502 may
form an outer surface of shaft 500. For instance, outer surface 501
may be uncovered or otherwise exposed to a surrounding environment.
As shown in the exemplary embodiment of FIG. 6, outer surface 501
may have a substantially circular cross-section.
[0057] The stiffness of shaft 500 may be varied, for example, by
altering the dimensions of shaft 500. For instance, a thickness of
inner tube 504, outer tube 502, and/or ribs 510 may be varied to
affect the stiffness of shaft 500. Inner tube 504 may have a
thickness of, for example, about 0.095 inches to about 0.105
inches. Outer tube 502 may have a thickness of, for example, about
0.030 inches to about 0.040 inches. Ribs 510 may have a thickness
of about 0.020 inches to about 0.030 inches. According to an
exemplary embodiment, the material of inner tube 504, outer tube
502, and ribs 510 may be selected to provide a desired stiffness
for shaft 500. Another method of controlling the stiffness of shaft
500 is selecting the number of ribs 510, according to an exemplary
embodiment. As shown in the exemplary embodiment of FIG. 6, shaft
500 may include four ribs 510. However, a shaft for a surgical
instrument may include, for example three ribs, five ribs, or other
numbers of ribs.
[0058] Further, although shaft 500 may lack stiffening wires, which
may be made out of a material having a relatively high stiffness,
such as a metal, and thus shaft 500 may be expected to have a lower
overall stiffness, shaft 500 has a sufficient stiffness but
advantageously exhibits an overall stiffness that is more easily
controlled and more uniform from one shaft to another in comparison
to shafts including stiffening wires. As a result, shaft 500
advantageously enhances movement control and minimizes movement of
end effector during actuation of the end effector, such as in
directions 230, 232 discussed above in regard to FIG. 2.
[0059] Turning to FIG. 7, an exemplary embodiment of a shaft 600 of
a surgical instrument is shown in cross section. Shaft 600 may be
defined by a single tube 602 that includes a lumen 601 for a drive
member 604 connecting a force transmission mechanism to an end
effector of the surgical instrument, as discussed in the exemplary
embodiments of FIGS. 1 and 2. According to an exemplary embodiment,
lumen 601 may be utilized during a cleaning operation by flushing
material through lumen 601. An inner surface 605 of tube 602 that
defines lumen 601 may be in contact with drive member 604,
according to an exemplary embodiment.
[0060] According to an exemplary embodiment, tube 602 may be
provided as a single piece tube. Thus, a body of shaft 600 may be
formed by tube 602. Further, as shown in the exemplary embodiment
of FIG. 7, tube 602 may be a continuously solid hollow cylinder
between the outer surface 603 of tube 602 and the inner surface 605
of tube 602 and thus lack any lumen (i.e., be lumenless). In other
words, tube 602 may be a hollow cylinder that includes a single
lumen, namely lumen 601 for drive member 604. According to an
exemplary embodiment, outer surface 603 of tube 602 may define an
outer surface of shaft 600. For instance, outer surface 603 may be
uncovered or otherwise exposed to a surrounding environment. As
shown in the exemplary embodiment of FIG. 6, outer surface 501 may
have a substantially circular cross-section.
[0061] According to an exemplary embodiment, tube 602 may be made
from a single material. Thus, a body of shaft 600 may be made from
a single material between inner surface 601 and outer surface 603.
Further, inner surface 601 may form an inner surface of the body of
shaft 600 and outer surface 603 may form an outer surface of the
body of shaft 600. According to an exemplary embodiment, tube 602
may be made by extruding a single material to form a hollow
cylinder, as shown in FIG. 7. According to an exemplary embodiment,
shaft 600 may consist of tube 602 and drive member 604.
[0062] By providing tube 602 with a single piece construction, a
shaft 600 may be advantageously provided that minimizes movement of
an end effector during actuation of the end effector, such as in
directions 230, 232 discussed above in regard to FIG. 2. Further,
although shaft 600 may lack stiffening wires, which may be made out
of a material that has a relatively high stiffness, such as a
metal, shaft 600 has a sufficient overall stiffness that is more
easily controlled and more uniform from one shaft to another in
comparison to shafts including stiffening wires.
[0063] As noted above, materials for a shaft may be selected to
affect the stiffness of a shaft. According to an exemplary
embodiment, inner tube 404 and outer tube 402 of FIG. 5; inner tube
504, outer tube 502, and ribs 510 of FIG. 6; and tube 602 of FIG. 7
may be made of PEEK. With regard to the exemplary embodiments of
FIGS. 6 and 7, the single piece constructions provided by inner
tube 504, outer tube 502, and ribs 510 in FIG. 6 and the single
piece construction provided by tube 602 in FIG. 7 may be provided
by a single piece comprising PEEK. PEEK may be selected as the
material to form the tubes of these exemplary embodiments because
of its desirable stiffness values and biocompatibility. For
instance, PEEK may be selected instead of FEP for these embodiments
because FEP is more compliant and deformable, which could lead to
movement of an end effector, such as in directions 230, 232
discussed above in regard to FIG. 2, if the FEP deformed.
[0064] According to an exemplary embodiment, PEEK may be in an
annealed condition. Further, PEEK may be unfilled, according to an
exemplary embodiment. Unfilled PEEK may have a tensile modulus of,
for example, about 535,000 psi to about 545,000 psi. According to
another exemplary embodiment, PEEK may include one or more fillers,
such as, for example, glass fiber reinforcement or carbon fiber
reinforcement. PEEK that includes a glass fiber reinforcement
filler may have a tensile modulus of, for example, about 1,650,000
psi to about 1,750,000 psi. PEEK that includes a carbon fiber
reinforcement filler may have a tensile modulus of, for example,
about 3,600,000 psi to about 3,950,000 psi. PEEK may be available
from Victrex.RTM. PLC of Lancashire UK. Exemplary commercial grades
of unfilled PEEK available from Victrex.RTM. PLC include PEEK 90G,
PEEK 151G, PEEK 151G, PEEK 381G, PEEK 450G, and PEEK 450G903.
Exemplary commercial grades of filled PEEK available from
Victrex.RTM. PLC include PEEK 90GL30, PEEK 150GL30, PEEK 450GL30,
PEEK 90CA30, PEEK 150CA30, PEEK 90CA30, PEEK 150CA30, PEEK 450CA30,
and PEEK 90HMF20. According to an embodiment, the material used for
a shaft may include a material to increase the lubricity of the
shaft. For instance, the material of the shaft may include, for
example, about 5% to about 10% of PTFE and/or perfluoropolyether
(PFPE). The addition of the material to increase lubricity of a
shaft may advantageously avoid the need for an additional sheath to
be placed over an exterior surface of the shaft to lower the
coefficient of friction of the outer surface to minimize friction
and wear.
[0065] Other materials may be used for the exemplary embodiments of
FIGS. 5-7. Other materials include, for example, acetal, nylon,
polyester, and sulfone plastics. Materials selected for the
exemplary embodiments of FIGS. 5-7 may be selected to provide a
shaft of a surgical instrument with a desired stiffness. In another
example, materials may be selected that are weldable to other
components of a surgical instrument. Further, the materials may be
selected to minimize damage and wear to an instrument shaft. For
instance, material(s) may be selected so that an instrument
exhibits substantially no damage after applying 2 lbf to a distal
tip of the instrument in a direction normal to a roll axis of the
instrument.
[0066] According to an exemplary embodiment, a shaft of a surgical
instrument lacking stiffening wires, such as according to the
exemplary embodiments of FIGS. 5-10, may be configured to have an
axial stiffness ranging from about 900 lbs/in to about 1250 lbs/in
and a bending stiffness ranging from about 50 lbs*in.sup.2 to about
65 lbs*in.sup.2, according to calculations. In contrast, a shaft
configured according to the exemplary embodiment of FIG. 4 to
include stiffening wires, may have an axial stiffness ranging from
about 400 to about 5000 lb/in and a bending stiffness ranging from
about 20 to about 500 lbs*in.sup.2, depending on the stiffening
wire to tube interface. Although the maximum calculated stiffness
for shafts lacking stiffening wires is lower, this stiffness is not
only sufficient but is also advantageously more uniform and
consistent from one shaft to another.
[0067] According to an exemplary embodiment, a shaft of a surgical
instrument may be configured so that a force required to advance or
withdraw the instrument through a cannula is no more than 5 lbf.
Turning to FIG. 11, an exemplary embodiment of a surgical
instrument is shown inserted within a curved cannula 1000 so that
shaft 1012 of the instrument has reached maximum insertion. When
advanced to maximum insertion, a distal end 1014 of instrument
shaft 1012 may extend a distance 1016 beyond a distal end 1010 of
cannula 1000 ranging, for example, from about 5 inches to about 11
inches. FIG. 12 shows an exemplary embodiment of the instrument
shaft 1012 withdrawn to a minimum insertion within cannula 1000. A
minimum insertion distance between a distal end 1014 of instrument
shaft 1012 and a distal end 1010 of cannula 1000 may range, for
example, from about 0.125 inches to about 0.250 inches. According
to an exemplary embodiment, a shaft of a surgical instrument may be
configured so that no more than about 2.5 lbf is required to
advance an instrument from a minimum insertion distance to a
maximum insertion distance within a curved cannula.
[0068] The stiffness of a shaft of a surgical instrument may be
evaluated, for example, by measuring movement of an end effector
when the end effector is actuated. For instance, when an instrument
has been advanced to the maximum insertion position shown in the
exemplary embodiment of FIG. 11, a weight may be hung from the
distal end 1014 of the shaft 1012 and a deflection 1004 of the
shaft 1012 relative to a longitudinal axis 1002 of the cannula 1000
may be determined. According to an exemplary embodiment, when a one
pound weight is hung from the distal end 1014 of shaft 1012, a
maximum deflection 1004 of about 1.5 inches occurs relative to the
longitudinal axis 1002 of cannula 1000.
[0069] As discussed above, a shaft of a surgical instrument may be
provided by a single piece tube, as discussed in the exemplary
embodiments of FIGS. 6 and 7. However, it may be advantageous to
provide a shaft with a sheath on an outer surface of the tube. For
instance, providing a sheath on the outer surface of a tube may
advantageously provide a lower coefficient of friction, which
reduces friction and wear when advancing and withdrawing an
instrument through a cannula. According to an exemplary embodiment,
a sheath may be made of a material having a lower coefficient of
friction than a tube material that the sheath is located upon. A
sheath may comprise, for example, ETFE or other sheath materials
used in the art.
[0070] Turning to FIG. 8, an exemplary embodiment of a shaft 700 is
shown that includes an outer tube 702 and an inner tube 704 that
forms a lumen 707 for a drive member 706. Shaft 700 may be formed
according to the exemplary embodiment of FIG. 5, except that a
sheath 710 is provided on an outer surface 709 of outer tube 702.
According to an exemplary embodiment, outer surface 709 may form an
outer surface of shaft 700, with sheath 710 provided on outer
surface 709. As shown in the exemplary embodiment of FIG. 9, a
shaft 800 may include an outer tube 802, an inner tube 804 that
forms a lumen 807 for a drive member 806, one or more lumens 808,
and ribs 810. Shaft 800 may be formed according to the exemplary
embodiment of FIG. 6, except that a sheath 820 is provided on an
outer surface 803 of outer tube 802. According to an exemplary
embodiment, outer surface 803 may form an outer surface of shaft
800, with sheath 820 provided on outer surface 803. Turning to FIG.
10, an exemplary embodiment of a shaft 900 is shown that includes a
single tube 902 that forms a lumen 901 for a drive member 904.
Shaft 900 may be formed according to the exemplary embodiment of
FIG. 7, except that a sheath 910 is provided on an outer surface
903 of tube 902. According to an exemplary embodiment, outer
surface 903 may form an outer surface of shaft 900, with sheath 910
provided on outer surface 903.
[0071] According to an exemplary embodiment, when a shaft of a
surgical instrument is provided with a sheath, such as in the
exemplary embodiments of FIGS. 8-10, dimensions of the shaft may be
redesigned to accommodate the sheath. For instance, the outer
diameter of the shaft may remain the same whether a sheath is
present or absent so that the stiffness of the shaft is maximized
while permitting the shaft to fit through a cannula. Therefore, if
a sheath is provided, the dimensions of the tube and other
components of the shaft may be reduced. For instance, in the
exemplary embodiment of FIG. 5, the radial thickness of outer tube
402 and/or inner tube 404 may be reduced. In another instance, in
the exemplary embodiment of FIG. 6, at least one of the radial
thickness of inner tube 504, the radial thickness of outer tube
502, and the length of ribs 510 may be reduced. In another
instance, in the exemplary embodiment of FIG. 7, the radial
thickness of tube 602 may be reduced.
[0072] Although the exemplary embodiments of FIGS. 4-7 show shafts
having a substantially smooth outer surface, shafts may have other
surface configurations. Turning to FIG. 13, a cross-sectional view
of an exemplary embodiment of a shaft 1100 is shown that includes a
plurality of projections 1102 on the outer surface 1104 of shaft
1100. Shaft 1100 may include a drive member 1110 connecting a force
transmission mechanism to an end effector of the surgical
instrument, as discussed in the exemplary embodiments of FIGS. 1
and 2. Further, shaft 1100 may be constructed according to any of
the exemplary embodiments of FIGS. 5-7. As shown in the exemplary
embodiment of FIG. 13, projections 1102 may extend a non-zero
distance along a radial direction 1106 from outer surface 1104. By
providing projections 1102, the amount of contact area between
shaft 1100 and an inner surface of a curved cannula may be reduced,
which advantageously reduces friction and wear. According to an
exemplary embodiment, projections 1102 may be sufficient to reduce
friction to a degree that shaft 1100 does not require a sheath to
minimize friction and wear. Further, projections 1102 are not
limited to what is shown in the exemplary embodiment of FIG. 13.
For instance, projections 1102 may be provided in fewer or greater
numbers, be spaced closer or further apart in a uniform or
non-uniform spacing, and/or may have different shapes.
[0073] By providing a surgical instrument according to the
exemplary embodiments discussed above, a surgical instrument may be
advantageously provided that is simpler to manufacture, less costly
to manufacture, and provides enhanced properties. For instance, a
shaft of the surgical instrument may minimize movement of an end
effector during actuation of the end effector, such as in
directions 230, 232 discussed above in regard to FIG. 2. Further,
although the shaft may lack stiffening wires made of a material
having a relatively high stiffness, the shaft has a sufficient
overall stiffness that is more easily controlled and more uniform
from one shaft to another in comparison to shafts that include
stiffening wires.
[0074] Further modifications and alternative embodiments will be
apparent to those of ordinary skill in the art in view of the
disclosure herein. For example, the systems and the methods may
include additional components or steps that were omitted from the
diagrams and description for clarity of operation. Accordingly,
this description is to be construed as illustrative only and is for
the purpose of teaching those skilled in the art the general manner
of carrying out the present teachings. It is to be understood that
the various embodiments shown and described herein are to be taken
as exemplary. Elements and materials, and arrangements of those
elements and materials, may be substituted for those illustrated
and described herein, parts and processes may be reversed, and
certain features of the present teachings may be utilized
independently, all as would be apparent to one skilled in the art
after having the benefit of the description herein. Changes may be
made in the elements described herein without departing from the
spirit and scope of the present teachings and following claims.
[0075] In this description, 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.
[0076] 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.
[0077] It is to be understood that the particular examples and
embodiments set forth herein are non-limiting, and modifications to
structure, dimensions, materials, and methodologies may be made
without departing from the scope of the present teachings.
[0078] Other embodiments in accordance with the present disclosure
will be apparent to those skilled in the art from consideration of
the specification and practice of the invention disclosed herein.
It is intended that the specification and examples be considered as
exemplary only, with a true scope and spirit being indicated by the
following claims.
* * * * *