U.S. patent application number 14/456168 was filed with the patent office on 2015-02-05 for endoscope working channel with multiple functionality.
The applicant listed for this patent is Boston Scientific Scimed, Inc.. Invention is credited to William CHURCHILL, Luis J. MASEDA, Roy SULLIVAN, Barry WEITZNER.
Application Number | 20150038784 14/456168 |
Document ID | / |
Family ID | 38111540 |
Filed Date | 2015-02-05 |
United States Patent
Application |
20150038784 |
Kind Code |
A1 |
MASEDA; Luis J. ; et
al. |
February 5, 2015 |
ENDOSCOPE WORKING CHANNEL WITH MULTIPLE FUNCTIONALITY
Abstract
Endoscopic instrument assemblies and methods for making and
using the same. An example endoscopic instrument assembly includes
an endoscope having a working channel and an endoscopic instrument
slidably disposed in the working channel. The inside surface of the
working channel and the outside surface of the endoscopic
instrument each have a non-circular cross-sectional shape along at
least a portion of their respective lengths.
Inventors: |
MASEDA; Luis J.; (Natick,
MA) ; WEITZNER; Barry; (Acton, MA) ; SULLIVAN;
Roy; (Uxbridge, MA) ; CHURCHILL; William;
(Bolton, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Boston Scientific Scimed, Inc. |
Maple Grove |
MN |
US |
|
|
Family ID: |
38111540 |
Appl. No.: |
14/456168 |
Filed: |
August 11, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13037537 |
Mar 1, 2011 |
8834352 |
|
|
14456168 |
|
|
|
|
11386861 |
Mar 22, 2006 |
7918783 |
|
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13037537 |
|
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Current U.S.
Class: |
600/104 ;
600/153 |
Current CPC
Class: |
A61B 2017/293 20130101;
A61B 1/018 20130101; A61B 1/00108 20130101; A61B 2017/2901
20130101 |
Class at
Publication: |
600/104 ;
600/153 |
International
Class: |
A61B 1/018 20060101
A61B001/018; A61B 1/00 20060101 A61B001/00 |
Claims
1-24. (canceled)
25. An endoscopic instrument, comprising: an endoscope having a
longitudinal axis, wherein the endoscope includes: a first portion
defining a first lumen having a first cross-sectional shape; and a
second portion defining a second lumen having a second
cross-sectional shape different from the first cross-sectional
shape, wherein the second portion is rotatable about the
longitudinal axis relative to the first portion; and a control
member configured to rotate the second portion about the
longitudinal axis relative to the first portion.
26. The endoscopic instrument of claim 25, wherein the control
member extends proximally.
27. The endoscopic instrument of claim 25, wherein the second lumen
is within the first lumen.
28. The endoscopic instrument of claim 25, wherein the control
member is configured to apply torque to a distal end of a tool
disposed in the second lumen.
29. The endoscopic instrument of claim 25, wherein the control
member includes one or more wires disposed around the second
portion.
30. The endoscopic instrument of claim 25, wherein the control
member includes a gear engaged with the second portion.
31. The endoscopic instrument of claim 25, wherein the first
cross-sectional shape is substantially circular.
32. The endoscopic instrument of claim 31, wherein the second
cross-sectional shape is substantially non-circular.
33. The endoscopic instrument of claim 32, wherein the second
cross-sectional shape is a polygonal cross-sectional shape.
34. The endoscopic instrument of claim 25, further comprising a
third portion having a third cross-sectional shape different from
the second cross-sectional shape.
35. An endoscopic instrument, comprising: an endoscope including a
lumen having a longitudinal axis, wherein the endoscope includes: a
first portion having a first inner perimeter; a second portion
having a second inner perimeter different from the first inner
perimeter; and a third portion having a third inner perimeter
different from the second inner perimeter, wherein the second
portion is disposed between the first portion and the third portion
and is rotatable about the longitudinal axis relative to the first
portion and the third portion; and a control member configured to
rotate the second portion about the longitudinal axis relative to
the first portion and the third portion.
36. The endoscopic instrument of claim 35, wherein the control
member extends proximally from the second portion.
37. The endoscopic instrument of claim 35, wherein the first
cross-sectional shape and third cross-sectional shape are
substantially circular and the second cross-sectional shape is
substantially non-circular.
38. The endoscopic instrument of claim 35, further comprising a
tool disposed in the lumen, wherein the control member is
configured to apply torque to the tool.
39. The endoscopic instrument of claim 35, wherein the control
member includes one or more wires disposed around the second
portion.
40. The endoscopic instrument of claim 35, wherein the control
member includes a gear engaged with the second portion.
41. A method of using an endoscopic instrument, comprising:
delivering an endoscope into a patient, the endoscope defining a
lumen having a longitudinal axis, wherein the endoscope includes a
first portion and a second portion, wherein the second portion is
within the first portion and is rotatable about the longitudinal
axis relative to the first portion; positioning a tool at least
partially within the second portion; rotating the second portion by
a control member extending outside the patient.
42. The method of claim 41, wherein the first portion has a first
cross-sectional shape; and the second portion has a second
cross-sectional shape different from the first cross-sectional
shape.
43. The method of claim 41, wherein the control member includes one
or more wires disposed around the second portion.
44. The method of claim 41, wherein the second portion includes a
plurality of teeth, the control member is a rod, and a distal end
of the rod includes a gear engaged with the plurality of teeth.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/037,537, filed on Mar. 1, 2011, which is a
continuation of U.S. patent application Ser. No. 11/386,861, filed
Mar. 22, 2006 (now U.S. Pat. No. 7,918,783), all of which are
incorporated herein by reference in their entireties.
FIELD OF THE INVENTION
[0002] This invention pertains broadly to surgical instruments.
More particularly, this invention pertains to an endoscope and
endoscopic instruments that are disposed in a working channel of
the endoscope.
BACKGROUND
[0003] A wide variety of medical devices have been developed for
medical use, for example, endoscopic and/or surgical use. Some of
these devices include endoscopes, endoscopic instruments, and other
related devices that have certain characteristics. Of the known
medical devices, each has certain advantages and disadvantages.
There is an ongoing need to provide alternative designs and methods
of making and using medical devices.
BRIEF SUMMARY
[0004] The invention provides design, material, and manufacturing
method alternatives for medical devices, for example, endoscopes,
endoscopic instruments, and endoscopic instrument assemblies. An
example endoscopic instrument assembly includes an endoscope having
a working channel and an endoscopic instrument slidably disposed in
the working channel. The inside surface of the working channel and
the outside surface of the endoscopic instrument each have a
non-circular cross-sectional shape along at least a portion of
their respective lengths. Methods for making and using medical
devices including endoscopic instrument assemblies are also
disclosed. Some of these and other features and characteristics of
the inventive devices and methods are described in more detail
below.
[0005] The above summary of some embodiments is not intended to
describe each disclosed embodiment or every implementation of the
present invention. The Figures, and Detailed Description, which
follow, more particularly exemplify these embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The invention may be more completely understood in
consideration of the following detailed description of various
embodiments of the invention in connection with the accompanying
drawings, in which:
[0007] FIG. 1 is side view of an example endoscopic instrument
assembly;
[0008] FIG. 2 is a cross-section across line 2-2 in FIG. 1;
[0009] FIG. 3 is a cross-sectional view of an example working
channel;
[0010] FIG. 3A is a cross-section across line 3A-3A in FIG. 3;
[0011] FIG. 3B is a cross-section across line 3B-3B in FIG. 3;
[0012] FIG. 4 is a side view of a portion of an example endoscopic
instrument;
[0013] FIG. 4A is a cross-section across line 4A-4A in FIG. 4;
[0014] FIG. 4B is a cross-section across line 4B-4B in FIG. 4;
[0015] FIG. 5 is a cross-sectional view of another example working
channel;
[0016] FIG. 6 is a cross-section across line 6-6 in FIG. 5;
[0017] FIG. 7 is an alternative example cross-section taken across
line 6-6 in FIG. 5;
[0018] FIG. 8 is a cross-sectional view of another example working
channel having a plurality of endoscopic instruments disposed
therein; and
[0019] FIG. 9 is a cross-sectional view of the working channel
shown in FIG. 8 having a plurality of different instruments
disposed therein.
DETAILED DESCRIPTION
[0020] The following description should be read with reference to
the drawings wherein like reference numerals indicate like elements
throughout the several views. The detailed description and drawings
illustrate example embodiments of the claimed invention.
[0021] FIG. 1 illustrates an example endoscopic instrument assembly
10. Assembly 10 includes an endoscope 12 and an endoscopic
instrument 14 disposed in a working channel (not shown in FIG. 1,
see FIG. 2 for example working channels) defined in endoscope 12.
Endoscope 12 includes an elongate tubular portion 18 and a proximal
handle portion 20 adapted to manipulate and direct the distal end
of tubular portion 18.
[0022] Endoscopic instrument 14 may include an end effector 22 and
one or more control members 24 that may manipulate or otherwise
control end effector 22. In some embodiments, end effector 22 may
be a biopsy forceps or linkage mechanism as depicted in FIG. 1.
Alternatively, end effector 22 may be a snare loop, scissors,
punch, needle, and the like, or any other suitable device. Control
member 24 may include a thumb ring 26 and a displaceable spool 28,
which can be used to manipulate and/or actuate end effector 22.
Some additional details regarding suitable types of end effectors
and control members (which can also be described as or take the
form of handles) can be found in U.S. Pat. Nos. 6,537,205;
6,840,900; 6,454,702; 6,881,186; 6,235,026; and 6,517,539, the
entire disclosures of which are incorporated herein by
reference.
[0023] FIG. 2 is a cross-sectional view of tubular portion 18 of
endoscope 12. Here it can be seen that tubular portion 18 may
include one or more channels. One or more of these channels, for
example channel 30, may be provided for receiving an optical scope
or camera device 32 (which may be built therein). A number of
additional lumens 34/36/38/40 may be included for receiving control
wires 42/44/46/48 that may extend from the handle portion 20
through the tubular portion 18. One or more working channels
50/52/54/56 may also be provided for receiving endoscopic
instruments, for example endoscopic instrument 14, therethrough.
Other lumens 58/60 may be provided for other purposes. Some
additional details regarding endoscopes are described in general in
U.S. Pat. No. 5,179,935 to Miyagi, which is incorporated herein by
reference in its entirety. It should be noted that tubular portion
18 could also be a tubular medical device other than an endoscope,
such as a catheter or guiding tube that includes any number of the
features and characteristics of similar devices disclosed herein.
Therefore, to the extent applicable, discussion found below
relating to channels and instruments may also be applicable to
tubular medical devices such as catheters or guiding tubes that
include one, two, three or more lumens or channels that are
configured to accommodate instruments.
[0024] Working channel 52, as depicted in FIG. 2, has a
non-circular cross-sectional shape. In this example, the
cross-sectional shape is that of a six-sided polygon (i.e., a
hexagon). It can be appreciated that a number of alternative shapes
may be utilized without departing from the spirit of the invention.
For example, the cross-sectional shape may resemble a three, four,
five, six, seven, eight, nine, ten, or more sided polygon. The
polygon may be regular (i.e., all sides having the same length and
all angles between the sides being equal) or irregular. In
addition, any other suitable "non-polygonal" shape may be utilized
including partially circular shapes, irregular shapes, random
shapes, other geometric shapes, or any other suitable shape. Other
configurations may include a screw thread or helical ridge or
groove formed in channel 52. It should be noted that a vast variety
of shapes are contemplated for working channel 52 as well as other
channels and instruments disclosed herein.
[0025] An endoscopic instrument 62 is disposed in channel 52.
Instrument 62 has a generally circular cross-sectional shape. The
differences between the shape of channel 52 and instrument 62 may
be desirable for a number of reasons. For example, because of the
differences in the shape, the blank or vacant space between channel
52 and instrument 62 may allow for fluids to be infused or
aspirated through channel 52 while instrument 62 is in place. In
some instances, a secondary device (e.g., a needle, guidewire,
etc.) may also be disposed in channel 56 adjacent instrument 62.
The converse of working channel 52 and instrument 62 is working
channel 56 and endoscopic instrument 64. Here, channel 56 has a
generally circular cross-sectional shape while instrument 64 has a
non-circular cross-sectional shape. This arrangement may be
desirable for similar reasons as the arrangement of channel 52 and
instrument 62.
[0026] In addition, the differences in shape between channels 52/56
and instruments 62/64 may also reduce the surface area in which
channels 52/56 and instruments 62/64 are in contact.
[0027] Reducing surface area contact or otherwise providing space
between the working channel and the endoscopic instrument may
reduce "backlash" (also known as "whip"). Backlash is understood to
be a phenomenon where rotation or other manipulations of an
instrument (e.g. instruments 62/64) on one end is not immediately
translated to the other end of the instrument until, after a
certain amount of un-translated motion occurs, the instrument
abruptly translates the motion and/or otherwise "whips" around to
catch up with the motion.
[0028] Channel 50 is similar to channel 52 in that it has a
non-circular cross-sectional shape. Unlike channel 52, however, is
that endoscopic instrument 14 disposed in channel 50 also has a
non-circular cross-sectional shape. The shapes of channel 50 and
instrument 14 are, thus, complementary, i.e., the inner surface of
working channel 50 has an inner perimeter and the outer surface of
endoscopic instrument 14 has an outer perimeter, and the inner
perimeter and the outer perimeter are substantially equal. The
complementary shapes allow instrument 14 to fit within channel 50
much like how a key fits in a lock.
[0029] Utilizing a "lock-and-key" relationship between channel 50
and instrument 14 may be desirable for a number of reasons. For
example, using complementary shapes allows the user to keep track
of the orientation of instrument 14 within channel 50. This may be
particularly useful when the endoscopic intervention depends on
instrument 14 having a particular orientation and/or when it is
helpful to the clinician to know what orientation instrument 14 is
in at any given time. For example, it may be useful for a clinician
to know whether a particular end effector 22 (e.g., a biopsy
forceps) is "rightside-up" or "upside-down" prior to attempting to
actuate the end effector 22. To further aid this orientation
capability, instrument 14 may also include a visual indicia of
origin (not shown) such as a colored marker or image that indicates
the orientation of instrument 14. Of course, a number of
alternative indicia of origin may also be used without departing
from the spirit of the invention.
[0030] Instrument 14' is disposed in channel 54 and is similar to
instrument 14 except that the cross-sectional shape of instrument
14' is defined by a sleeve or coating 66 disposed on the outer
surface of instrument 14'. Sleeve 66 allows an otherwise round
instrument 14' to utilize the lock-and-key relationship described
above and take advantage of its desirable properties.
[0031] Sleeve 66 may include a number of different materials. For
example, sleeve 66 may comprise a polymer such as
polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene
(ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene
(POM, for example, DELRIN.RTM. available from DuPont), polyether
block ester, polyurethane, polypropylene (PP), polyvinylchloride
(PVC), polyether-ester (for example, ARNITEL.RTM. available from
DSM Engineering Plastics), ether or ester based copolymers (for
example, butylene/poly(alkylene ether) phthalate and/or other
polyester elastomers such as HYTREL.RTM. available from DuPont),
polyamide (for example, DURETHAN.RTM. available from Bayer or
CRISTAMID.RTM. available from Elf Atochem), elastomeric polyamides,
block polyamide/ethers, polyether block amide (PEBA, for example
available under the trade name PEBAX.RTM.), ethylene vinyl acetate
copolymers (EVA), silicones, polyethylene (PE), Marlex high-density
polyethylene, Marlex low-density polyethylene, linear low density
polyethylene (for example REXELL.RTM.), polyester, polybutylene
terephthalate (PBT), polyethylene terephthalate (PET),
polytrimethylene terephthalate, polyethylene naphthalate (PEN),
polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI),
polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly
paraphenylene terephthalamide (for example, KEVLAR.RTM.),
polysulfone, nylon, nylon-12 (such as GRILAMID.RTM. available from
EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene
vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene
chloride (PVdC), polycarbonates, ionomers, biocompatible polymers,
other suitable materials, or mixtures, combinations, copolymers
thereof, polymer/metal composites, and the like. In some
embodiments, lubricious polymers (including those listed above such
as polytetrafluoroethylene) may desirably improve the ability for
instrument 14' to move within channel 54. Moreover, because
increased lubricity may be desirable, sleeve 66 can also be applied
to the outer surface of instrument 14 or any other instrument
having a non-circular cross-sectional shape. Sleeves or lubricious
coatings may also be utilized for channels and other instruments
described herein so that these instruments may more easily move
within these channels.
[0032] Endoscopic instrument assembly 10 may be used by disposing
tubular portion 18 within a body lumen. For example, for an
endoscopic procedure that accesses the stomach, tubular portion 18
may extend through the mouth of a patient, down through the
esophagus, and into the stomach. Once positioned, instrument 14 (or
any other instrument described herein) can extend through the
appropriate working channel and into the body lumen. Inside the
body lumen, the instrument may be actuated so as to perform its
intended intervention.
[0033] It is once again useful to consider that a number of
different cross-sectional shapes are contemplated for the various
working channels and endoscopic instruments described herein. For
example, a number of different polygons (e.g., one, two, three,
four, five, six, seven, eight, nine, or more sided), partially
rounded, irregular, geometric, non-geometric, or other shapes can
be used for any of the channels or instruments without departing
from the spirit of the invention. It is worth noting that a
cross-sectional shape may be described as an inner or outer
diameter, an inner or outer perimeter, or by any other suitable
designation. To the extent applicable, these descriptions can be
used interchangeably.
[0034] In some embodiments, the non-circular cross-sectional shape
of working channels 50/52/54 and instruments 14/14'/64 extend the
full length of each given device. However, this need not be the
case. For example, FIG. 3 illustrates a cross-section of another
example working channel 68 that has an inner surface 70 with a
first region 72 having a non-circular cross-sectional shape and a
second region 74 with a generally circular cross-sectional shape. A
transverse cross-sectional representation of first region 72 is
depicted in FIG. 3A and a transverse cross-sectional representation
of second region 74 is depicted in FIG. 3B.
[0035] Analogously, FIG. 4 illustrates a side view of another
example endoscopic instrument 114 that has an outer surface 76 with
a first region 78 having a non-circular cross-sectional shape and a
second region 80 with a generally circular cross-sectional shape. A
transverse cross-sectional representation of first region 78 is
depicted in FIG. 4A and a transverse cross-sectional representation
of second region 80 is depicted in FIG. 4B.
[0036] Instrument 114 and channel 68 may be used together or with
any other suitable partner. When used together, it can be
appreciated that when non-circular first region 78 of instrument
114 engages non-circular first region 72 of channel 68, instrument
114 "keys" channel 68. Conversely, when first region 78 of
instrument 114 is disposed adjacent second region 74 of channel 68,
instrument 114 can be more easily rotated within channel 68. The
combination of these design features allows the clinician to take
advantage of the desirable properties of both circular and
non-circular devices by simply shifting the longitudinal position
of instrument 114 relative to channel 68.
[0037] Designs like these that utilize a non-circular
cross-sectional shape along only a portion of the length may
provide the endoscopic assembly with a number of desirable
features. For example, because a substantial portion of the length
of channel 68 and/or instrument 114 have a generally circular
cross-sectional shape, non-circular first regions 72/78, when not
engaged with one-another, may have reduced surface area contact
with circular second regions 74/80. This relationship can reduce
backlash and allow for fluid infusion and/or aspiration. Similarly,
when non-circular first regions 72/78 are engaged with one another,
they may desirably have improved orientation compatibility and
otherwise take advantage of the desirable benefits of the
"lock-and-key" arrangement.
[0038] The length, number, position, and shape of first regions
72/78 can vary in a number of different embodiments. For example,
non-circular first regions 72/78 can span any portion of the length
of either channel 68 or instrument 114. Likewise, differing
embodiments of channel 68 and instrument 114 may include one, two,
three, four, or more first regions 72/78. In addition, the various
non-circular first regions 72/78 can be positioned at essentially
any longitudinal position along channel 68 and instrument 114. For
example, FIGS. 3 and 4 illustrate first regions 72/78 being
positioned away from the ends of channel 68 and instrument 114.
However, this need not be the case as numerous embodiments are
contemplated that position first regions 72/78 adjacent the
proximal end, distal end, or both of channel 68 and instrument 114,
respectively. Similarly, the shape of first regions 72/78 can vary
to be any useful shape.
[0039] FIG. 5 illustrates another example channel 82 that is
similar to other channels described herein. Channel 82 includes an
inner surface 83 having a section 84 with a generally circular
cross-sectional shape and another section 86 having a non-circular
cross-sectional shape. Section 86 may include a rotatable member 87
that is rotatable within section 84 as best seen in FIG. 6. Here it
can be seen that rotatable member 87 includes a plurality of teeth
or gears 88. A control member or rod 90 having a gear 92 can be
extended through an. opening 93 in section 84 and into engagement
with teeth 88. Rod 90 extends proximally to a position accessible
by the clinician. With gear 92 engaged with teeth 88, rotation of
rod 90 rotates rotatable member 87. Thus, rod 90 and gears 88
function much like a worm gear and this configuration can be
utilized to rotate section 86 when desired. In some embodiments, a
second rod 90a may also be utilized on the opposing side of section
84, and/or a motor may be disposed in or adjacent working channel
82 and be coupled to member 87 for rotating member 87. In
alternative embodiments, rotatable member 87 and/or rod 90 may have
mating or complementary screw threads (or a screw thread on one
structure and a gear on the other to drive the screw thread) that
provide essentially the same features.
[0040] Rod 90 may utilize any number of different forms and/or
material compositions. For example, rod 90 may be made from a metal
or metal alloy. Some examples of suitable metals and metal alloys
include stainless steel, such as 304V, 304L, and 316LV stainless
steel; mild steel; nickel-titanium alloy such as linear-elastic or
super-elastic nitinol, nickel-chromium alloy, nickel-chromium-iron
alloy, cobalt alloy, tungsten or tungsten alloys, MP35-N (having a
composition of about 35% Ni, 35% Co, 20% Cr, 9.75% Mo, a maximum 1%
Fe, a maximum 1% Ti, a maximum 0.25% C, a maximum 0.15% Mn, and a
maximum 0.15% Si), hastelloy, monel 400, inconel 825, or the like;
other Co--Cr alloys; platinum enriched stainless steel; or other
suitable material. Alternatively, rod 90 may comprise a polymer,
metal-polymer composite, and the like, or any other suitable
material.
[0041] Section 86 and rotatable member 87 may be desirable for a
number of reasons. For example, a clinician may dispose an
endoscopic instrument (such as any of those shown or described
herein) through channel 82 and then need to rotate the instrument.
With a non-circular section of the instrument "keyed" with section
86, a clinician can rotate rod 90 to rotate rotatable member 87
and, consequently, the instrument.
[0042] Another desirable feature of rotatable member 87 is that
because it may be placed at or near the distal end of channel 82,
torque can be applied directly at the distal end of the instrument
rather than at the proximal end of the instrument. This may result
in a more efficient transfer of torque and it may reduce the
incidence of backlash because of the fact that torque is being
applied to the instrument at a location that is much closer to
where torque transmission is desired (e.g., near the end
effector).
[0043] FIG. 7 illustrates an alternative section 186 that includes
rotatable member 187 that is rotatable within section 84 of channel
82. One or more wires 194 are disposed about rotatable member 187,
with ends 192a/192b of wires 194 extending into openings 93 and
then extending proximally to a location accessible by the
clinician. Ends 192a/192b or wires 194 can be pulled by the
clinician in order to rotate section 186. For the same reasons set
forth above, this may help to efficiently transmit torque and
reduce backlash.
[0044] FIG. 8 illustrates another example working channel 96 that
is similar in form and function to the other channels described
above. A plurality of instruments 98a/98b are disposed in channel
96. This arrangement demonstrates that multiple instruments
98a/98b, each having a non-circular cross-sectional shape, can be
disposed in channel 96. In some embodiments, instruments 98a/98b
may have a combined shape that is complementary to the
cross-sectional shape of channel 96. The combination of instruments
98a/98b, thus, may take advantage of the desirable features of the
"lock-and-key" arrangement described above. Alternatively, a
plurality of generally circular instruments 99a/99b may be disposed
in channel 96 as shown in FIG. 9. This arrangement may be desirable
by reducing the surface area contract between instruments 99a/99b
and channel 96 as described above. Of course, a combination of
these arrangements is also contemplated where a non-circular
instrument (e.g., instrument 98a) and a generally circular
instrument (e.g., instrument 99a) are disposed in channel 96.
Regardless of what arrangement is utilized, any combination of
instruments 98a/98b/99a/99b may be used with any suitable channel,
including any of those described herein.
[0045] It should be understood that this disclosure is, in many
respects, only illustrative. Changes may be made in details,
particularly in matters of shape, size, and arrangement of steps
without exceeding the scope of the invention. The invention's scope
is, of course, defined in the language in which the appended claims
are expressed.
* * * * *