U.S. patent number RE34,110 [Application Number 07/727,224] was granted by the patent office on 1992-10-27 for endoscope for use with a disposable sheath.
This patent grant is currently assigned to Opielab, Inc.. Invention is credited to Eric A. Opie, deceased, Fred E. Silverstein.
United States Patent |
RE34,110 |
Opie, deceased , et
al. |
October 27, 1992 |
**Please see images for:
( Certificate of Correction ) ** |
Endoscope for use with a disposable sheath
Abstract
An endoscope specially adapted for use with a disposable sheath
having an outer casing and one or more internal channels. The
endoscope includes a tip portion connected to a control handle
through a flexible insertion tube. The insertion tube is formed by
a braided wire tube covered by a flexible waterproof coating and
surrounding a resilient D-shaped tube through which optical
components for the endoscope extend. A longitudinally extending
groove is formed in the braided tube to receive and channel(s). The
groove extends perpendicular to, and makes contact with, a
generally planar portion of the D-shaped tube so that the D-shaped
tube can restrict deformation of the groove as the insertion tube
bends. Longitudinal channels are formed on opposite sides of the
groove to house control cables extending from the control handle to
the tip portion. The cables are surrounded by tubes that
collectively occupy the entire channel so that the tubes prevent
the channel, and hence the groove, from collapsing.
Inventors: |
Opie, deceased; Eric A. (late
of Brier, WA), Silverstein; Fred E. (Seattle, WA) |
Assignee: |
Opielab, Inc. (Seattle,
WA)
|
Family
ID: |
26880810 |
Appl.
No.: |
07/727,224 |
Filed: |
June 25, 1991 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
185116 |
Apr 22, 1988 |
04869238 |
Sep 26, 1989 |
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Current U.S.
Class: |
600/128; 600/123;
600/131; 600/139; 600/140; 600/920 |
Current CPC
Class: |
A61B
1/00071 (20130101); A61B 1/00073 (20130101); A61B
1/00142 (20130101); A61B 1/00165 (20130101); A61B
1/0055 (20130101); A61B 1/042 (20130101) |
Current International
Class: |
A61B
1/00 (20060101); A61B 1/04 (20060101); A61B
1/005 (20060101); A61B 001/00 () |
Field of
Search: |
;128/4,5,6,7 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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184778 |
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May 1985 |
|
EP |
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2150595 |
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Oct 1971 |
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DE |
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Primary Examiner: Grieb; William H.
Attorney, Agent or Firm: Seed and Berry
Claims
We claim:
1. An endoscope for use with a disposable sheath having an
elongated casing surrounding at least one channel, said endoscope
comprising:
a tip portion having an optics window;
a control handle having a set of controls for controlling the
angular orientation of said tip portion;
an insertion tube extending between said tip portion and said
control handle, said insertion tube including a resilient, D-shaped
tube having a cylindrical portion extending between a substantially
planar diameter portion, a braided tube enclosing said D-shaped
tube, with the cylindrical portion of said D-shaped tube abutting
said braided tube, said braided tube having formed therein a
longitudinal groove extending inwardly from said braided tube
diametrically opposite said D-shaped tube, and a coating of a
flexible, waterproof material tightly surrounding the outer surface
of said braided tube; and
an imaging system extending through said D-shaped tube from said
control handle to said tip portion, whereby said sheath may be
installed on said endoscope with said casing surrounding said
insertion tube and said tip portion and said channel positioned in
said groove.
2. The endoscope of claim 1 wherein said imaging system comprises
an eyepiece mounted on said control handle, a first optical fiber
extending through the interior of said D-shaped tube from the
optics window of said tip portion to said eyepiece, and a second
optical fiber extending from the optics window of said tip portion
to an external illumination device.
3. The endoscope of claim 1 wherein said imaging system comprises a
miniature television camera mounted in said tip portion behind said
optics window, an electrical cable extending through said D-shaped
tube from said tip portion to said control handle for coupling a
video signal generated by said television camera to said control
handle, an electrically powered light mounted in said tip portion
behind said optics window, and a pair of conductors extending
through said D-shaped tube from said tip portion to said control
handle for applying electrical power to said light.
4. The endoscope of claim 1, further including a plurality of
longitudinally spaced wires extending from one side of said
insertion tube to the other adjacent the apexes of said D-shaped
tube to prevent said insertion tube from deforming in a direction
transverse to the plane of said groove.
5. The endoscope of claim 1, further including a pair of channels
formed in said insertion tube within said braided tube on opposite
sides of said groove, and a plurality of control cables extending
through said channels from said control handle to said tip
portion.
6. The endoscope of claim 5, further including a flexible control
cable tube surrounding each of said control cables with said
channels, and wherein said flexible control cable tubes
collectively occupy substantially all of the volume contained
within said channels and whereby said control cable tubes
substantially prevent the walls of said groove from collapsing.
7. The endoscope of claim 6, further including a filter of
resilient material filling any portion of said control channels
that is not occupied by said control cable tubes.
8. The endoscope of claim 1, further including a plurality of
longitudinally spaced ribs extending between the apexes of said
D-shaped tube, said ribs having a pair of semicylindrical walls
separated by an inwardly extending, U-shaped section conforming to
the shape of said groove, whereby said ribs stabilize said
insertion tube and groove responsive to bending of said insertion
tube.
9. The endoscope of claim 8 wherein said ribs are welded to said
D-shaped tube near the apexes thereof.
10. The endoscope of claim 8 wherein said ribs extend around at
least a portion of the outer periphery of the cylindrical portion
of said D-shaped tube.
11. The endoscope of claim 1 wherein said D-shaped tube is formed
by a plurality of concentric coils of flexible ribbon, with
adjacent coils helically wound in opposite directions.
12. The endoscope of claim 1 wherein the portion of said braided
tube that forms said groove contacts the diameter portion of said
D-shaped tube so that said D-shaped tube can stabilize said
groove.
13. An endoscope insertion tube for use with a disposable sheath
having an elongated casing surrounding at least one channel,
comprising:
a generally cylindrical tube of braided, resilient material having
a longitudinally extending groove formed therein configured to
receive the channel of said sheath;
a support member extending transversely across said braided tube
along a diameter thereof that is generally perpendicular to the
plane of said groove, said support member preventing deformation of
said tube in said transverse direction;
an imaging system extending through said braided tube on the side
of said support member opposite said groove; and
a flexible, resilient covering bonded to the outer surface of said
braided tube.
14. The insertion tube of claim 13 wherein said support member
comprises a resilient tube having a D-shaped cross section, said
D-shaped tube being positioned within said braided tube, with a
cylindrical portion of said D-shaped tube abutting said braided
tube and a generally planar section of said D-shaped tube extending
diametrically across said braided tube so that said D-shaped tube
divides said braided tube substantially in half.
15. The insertion tube of claim 14 wherein said D-shaped tube is
formed by a plurality of concentric coils of flexible ribbon, with
adjacent coils helically wound in opposite directions.
16. The insertion of claim 14 wherein the portion of said braided
tube that forms said groove contacts the diameter portion of said
D-shaped tube so that said D-shaped tube can stabilize said
groove.
17. The insertion tube of claim 13, further including a plurality
of longitudinally spaced ribs extending between the apexes of said
D-shaped tube, said ribs having a pair of semicylindrical walls
separated by an inwardly extending, U-shaped section conforming to
the shape of said groove, whereby said ribs stabilize said
insertion tube and groove responsive to bending of said insertion
tube.
18. The insertion tube of claim 17 wherein said ribs are welded to
said D-shaped tube near the apexes thereof.
19. The insertion tube of claim 17 wherein said ribs extend around
at least a portion of the outer periphery of the cylindrical
portion of said D-shaped tube.
20. The insertion tube of claim 13 wherein said support member
includes a plurality of longitudinally spaced wires extending from
one side of said braided tube to the other to prevent said
insertion tube from deforming in a direction transverse to the
plane of said groove.
21. The insertion tube of claim 13, further including a pair of
channels formed in said insertion tube within said braided tube on
opposite sides of said groove, and a plurality of control cables
extending through said channels from said control handle to said
tip portion.
22. The insertion tube of claim 21, further including a flexible
control cable tube surrounding each of said control cables within
said channels, and wherein said flexible control cable tubes
collectively occupy substantially all of the volume contained
within said channels and whereby said control cable tubes
substantially prevent the walls of said groove from collapsing.
23. The insertion tube of claim 22, further including a filter of
resilient material filling any portion of said control channels
that is not occupied by said control cable tubes.
24. A support member for use in the insertion tube of an endoscope,
said support member comprising a plurality of concentric coils of
resilient ribbon wire arranged with adjacent coils helically wound
in opposite directions, each of said coils having a D-shaped cross
section. .Iadd.
25. An endoscope for use with a disposable sheath having an
elongated casing and at least one channel extending along said
casing, said endoscope comprising:
a tip portion having an optics window;
a control handle having a set of controls for controlling the
angular orientation of said tip portion;
an insertion tube extending between said tip portion and said
control handle, said insertion tube extending a flexible tube
having a non-cylindrical cross-section, a braided tube enclosing
said flexible tube, and a coating of a flexible waterproof material
tightly surrounding the outer surface of said braided tube; and
an imaging system extending through said flexible tube from said
control handle to said tip portion, whereby said sheath may be
installed on said endoscope with said casing surrounding said
insertion tube and said tip portion and said channel positioned
against said flexible tube. .Iaddend. .Iadd.
26. The endoscope of claim 25 wherein said imaging system comprises
an eyepiece mounted on said control handle, a first optical fiber
extending through the interior of said flexible tube from the
optics window of said tip portion to said eyepiece, and a second
optical fiber extending from the optics window of said tip portion
to an external illumination device. .Iaddend. .Iadd.27. The
endoscope of claim 25 wherein said imaging system comprises a
miniature television camera mounted in said tip portion behind said
optics window, an electrical cable extending through said flexible
tube from said tip portion to said control handle for coupling a
video signal generated by said television camera to said handle, an
electrically powered light mounted in said tip portion behind said
optics window, and a pair of conductors extending through said
flexible tube from said tip portion to said control handle for
applying electrical power to said light. .Iaddend. .Iadd.28. The
endoscope of claim 25 wherein said flexible tube is formed by a
plurality of concentric coils of flexible ribbon, with adjacent
coils helically wound in opposite directions. .Iaddend. .Iadd.29.
The endoscope of claim 25 wherein said flexible tube has a
generally D-shaped configuration formed by a cylindrical portion
extending between opposite longitudinal edges of a substantially
planar diameter portion. .Iaddend.
Description
TECHNICAL FIELD
This invention relates to the field of endoscopy, and more
particularly, to the construction of the basic endoscope core of a
device for inexpensively isolating an endoscope from virus and
bacteria.
BACKGROUND ART
The use of endoscopes for diagnostic and therapeutic indications is
rapidly expanding. To improve performance, endoscopes have been
optimized to best accomplish their purpose. Therefore, there are
upper endoscopes for examination of the esophagus, stomach and
duodenum; colonoscopes for examining the colon; angioscopes for
examining blood vessels; bronchoscopes for examining the bronchi;
laparoscopes for examining the peritoneal cavity; and arthroscopes
for examining joint spaces. The discussion which follows will apply
to all of these types of endoscopes.
Instruments to examine the rectum and sigmoid colon, known as
"flexible sigmoidoscopes," are good examples of the usefulness of
endoscopic technology. These devices are expensive, and they are
used in a contaminated environment for a procedure which is brief
(five to ten minutes) and where problems of cleaning time and
contamination are important factors. There has been a large
increase in the use of the flexible sigmoidoscope for use in
screening symptomatic and asymptomatic patients for colon and
rectal cancer. Ideally, flexible sigmoidoscopes must be used
rapidly and inexpensively in order to maintain the cost of such
screening at acceptable levels. Typically, a clinic would like to
perform five sigmoidoscope examinations each hour. A significant
problem with making such examinations quick and inexpensive is the
time necessary for adequately cleaning the device.
Although endoscopes can be cleaned in about two to four minutes,
this relatively cursory cleaning may not be adequate for complete
disinfection or sterilization. Even a more complete cleaning,
requiring on the order of eight to ten minutes, may not allow
adequate cleaning, particularly in view of the increasing problems
with contagious viruses. Even with the use of chemicals such as
gluteraldehyde, adequate cleanliness may not be possible.
The cleaning problem not only includes the outside of the
endoscope, but also the multiple small channels inside the
endoscope. This includes channels for: air insufflation; water to
wash the tip; and biopsy and suction. Each channel also has a
control valve. These channels extend along the length of the
endoscope and come into contact with body tissues and fluids. It is
extremely difficult to adequately clean these channels even when
skilled health practitioners spend a great deal of time on the
cleaning procedure.
Even if endoscopes can be adequately cleaned in eight to ten
minutes, the cleaning still prevents endoscopy examinations from
being relatively inexpensive. While a physician may spend five to
ten minutes performing some types of endoscopy, he or she will
generally waste a great deal of time waiting for the endoscope to
be cleaned before he or she can conduct another endoscopy. A
partial solution to the "idle time" problem is to purchase multiple
instruments so one can be used as the others are being cleaned.
However, the expense of having duplicate endoscopes of each of the
many types described above makes this solution impractical
especially for physicians offices and smaller clinics.
Not only must the idle time of the physician be added to the cost
of endoscopic examinations, but the same spent by a nurse or other
hospital personnel in the cleaning as well as the cost of
disinfecting chemicals and other costs of the cleaning process must
also be added to the cost of the examination. Although automatic
washing machines are available to clean endoscopes, these machines
are expensive, take up significant amounts of space, are noisy, and
are not faster than washing by hand. Further, regardless of whether
the cleaning is done manually or by machine, the cleaning chemicals
can be harmful to the endoscope and thus significantly shorten its
life. The cleaning chemicals, being toxic, are also potentially
injurious to the staff who use them and to the environment into
which they are discharged. To use some of these chemicals safely,
such as gluteraldehyde, requires a dedicated ventilated hood, which
uses up space and is expensive to install and operate. The
chemicals are also potentially toxic to the patient in that, if
residue remains after cleaning and rinsing the instrument, the
patient could have a reaction to the chemicals.
As a result of these many problems, conventional endoscope cleaning
techniques greatly increase the cost of endoscopic procedures.
Furthermore, while the risk of contamination using endoscopes is
often far less than the risk of alternative procedures, such as
surgery, there is nevertheless a risk that endoscopes are not
cleaned adequately to prevent the risk of transmission of
infectious diseases from one patient to the next.
In the health care field, the problem of contaminated instruments
transmitting disease from one patient to the next have generally
been solved by making such instruments disposable. However, this
approach has not been thought possible in the field of endoscopy
because endoscopes are very expensive instruments. Moreover, it has
not been thought possible to isolate the endoscope from the patient
or the external environment because the endoscope itself has
channels inside it that are used as conduits for body fluids and
tissues, such as, for example, in taking biopsies. The only method
currently available to actually sterilize an endoscope is to use
gas sterilization with ethylene oxide gas. However, there are
several disadvantages in using this procedure. The procedure is
very slow (up to 24 hours), during which time the endoscope cannot
be used. Also, the gas affects the plastic of the endoscope and may
limit its lifespan. Finally, the gas is toxic and, therefore, great
care must be taken to ensure that no residue remains that might
cause patient or staff irritation or allergic reaction during
contact with the endoscope.
As a result of the above-described limitations in using and
cleaning endoscopes by conventional techniques, there has not
heretofore been an acceptable solution to the problem of making
endoscopy procedures both inexpensive and entirely safe.
A new approach to the problem of endoscope contamination is
described in U.S. Pat. No. 4,646,722. This new approach involves
the use of an endoscope sheath having a flexible tube surrounding
the elongated core of an endoscope. The flexible tube has a
transparent window near its distal end positioned in front of the
viewing window of the endoscope. Channels that come into contact
with the patient or the patient's body fluids (e.g., channels for
taking biopsies, injecting air or injecting water to wash the
window of the sheath) extend along the endoscope, either inside or
outside the sheath. Where the channels are positioned inside the
sheath, they may be inserted in a longitudinal groove formed in the
endoscope core. The protective sheath may be used with either
end-viewing endoscopes or side-viewing endoscopes. The protective
sheath may be installed by rolling the elastomeric tube into an
annular configuration and then unrolling the tube over the core of
the endoscope. Alternatively, the tube may be inflated in its
unrolled configuration to expand the tube and allow it to be easily
slipped onto the endoscope core. A variety of specialized
endoscopes may be created by using protective sheaths having a
variety of special purpose medical instruments mounted at the end
of a biopsy channel and operated through the channel.
The endoscope used in the implementation of the above-described
concept in one configuration must have a groove formed along its
length. A tube is inserted into this groove to provide channels for
air, water and suction. Once the groove is inserted, it is covered
with the sheath. After use, the sheath and channel insert are
removed and disposed of, leaving the endoscope free of
contamination resulting from the endoscopic procedure. Construction
of a flexible, strong, torque-stable endoscope with a groove
requires new approaches to endoscope construction. Standard
flexible endoscopes are constructed of an armor, usually consisting
of three layers: one or more metal coils, usually manufactured from
wire ribbon in a helical pattern to give the device compressive
strength; a wire mesh to give the outer surface continuity to
partially control flexibility and torque stability; and a plastic
polymer to make the tube fluid-tight and to entrap the wire mesh
braid to control flexibility and to add some torque stability. The
plastic also provides a slippery surface to facilitate passage of
the endoscope.
The conventional endoscope structure described above is unstable
for shapes other than round, for example, with a groove along its
length. If the armor coil is simply indented, it loses flexibility
and compressive strength, both of which are essential for
endoscopes. Because of its heavy use in a variety of environments
by a variety of personnel, endoscopes must have acceptable strength
to avoid collapse of the walls, resulting in injury to the delicate
and expensive optical system (fiberoptic or video) and light
system. It is also essential to ensure that the endoscope wall is
thin to keep the overall diameter of the endoscope as small as
possible to improve patient compliance and to make as much room
available as possible for elements inside the tube. For example,
the biopsy channel should be as large as possible to provide the
best instrument function. Finally, manipulation of the controls of
the endoscope must be directionally insensitive so that the
endoscope will react in the same manner regardless of the direction
in which it is manipulated. Ideally, the endoscope should have the
same "feel" as conventional endoscopes.
DISCLOSURE OF THE INVENTION
It is the object of the invention to provide an endoscope that is
flexible, strong and torque stable and has a groove along its
length so that it can be used with a disposable sheath, as
described in U.S. Pat. No. 4,646,722.
It is another object of the invention to provide an endoscope
having a longitudinal groove for receiving the channel(s) of a
disposable sheath that operates in the same manner as conventional
endoscopes and that has the same "feel" as conventional
endoscopes.
It is another object of the invention to provide an endoscope
having a longitudinal groove for receiving the channel(s) of a
disposable sheath that has uniform control characteristics in all
directions.
It a still another object of the invention to provide an endoscope
having a longitudinal groove for receiving the channel(s) of a
disposable sheath that is substantially as sturdy as conventional
endoscopes so that it can withstand heavy clinical use.
It a further object of the invention to provide an endoscope having
a longitudinal groove for receiving the channel(s) of a disposable
sheath that is constricted in a manner that prevents the groove
from collapsing when the endoscope is bent.
These and other objects of the invention are provided by an
endoscope having a tip portion including an optics window, a
control handle having a set of controls for controlling the angular
orientation of the tip portion, an insertion tube extending between
the tip portion and the control handle, and an imaging system. The
core of the insertion tube is a resilient, D-shaped tube through
which the components of the imaging system extend. The D-shaped
tube is positioned within a braided tube, with the braided tube
abutting a cylindrical portion of said D-shaped tube. A
longitudinal groove is formed in the braided tube diametrically
opposite the D-shaped tube, and a coating of a flexible, waterproof
material is bonded to the outer surface of the braided tube. The
portion of the braided tube forming the groove preferably contacts
the D-shaped tube so that the D-shaped tube can stabilize the
groove. A plurality of longitudinally spaced wires may extend from
one side of the insertion tube to the other adjacent the apexes of
the D-shaped tube to prevent the insertion tube from deforming in a
direction transverse to the plane of the groove. A pair of channels
may be formed in the insertion tube on opposite sides of the groove
to house a plurality of control cables extending from the control
handle to the tip portion. The control cables are surrounded by
respective flexible tubes that may collectively occupy
substantially all of the volume contained within the channels. As a
result, the tubes surrounding the control cables can prevent the
walls of the groove from collapsing. The insertion tube may also
include a plurality of longitudinally spaced ribs extending between
the apexes of the D-shaped tube. Each of the ribs has a pair of
semicylindrical walls separated by an inwardly extending, U-shaped
section conforming to the shape of the groove. The ribs stabilize
the insertion tube and groove as the insertion tube bends.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a conventional endoscope.
FIG. 2 is an isometric view of the inventive endoscope ready for
use with a disposable sheath, having a biopsy channel positioned in
a longitudinal groove formed in the endoscope.
FIG. 3 is an isometric sectional view taken along the line 3--3 in
FIG. 2, with the disposable sheath removed for clarity of
illustration.
FIG. 4 is a broken isometric view of a specially configured
cylindrical coil used to form a principal component of the
inventive endoscope.
FIG. 5 is a cross-sectional view showing a method of forming a
D-shaped tube from the cylindrical tube illustrated in FIG. 4.
FIG. 6 is an isometric view of an alternative construction of the
inventive endoscope.
FIG. 7 is an isometric view of another alternative construction of
the inventive endoscope.
FIG. 8 is an isometric view of still another alternative
construction of the inventive endoscope.
BEST MODE FOR CARRYING OUT THE INVENTION
The inventive endoscope, like the conventional endoscope 10
illustrated in FIG. 1, includes a tip portion 12, a flexible
insertion tube 14, and a control handle 16.
The tip portion 12 includes an optics window 20, a biopsy port 22,
a water nozzle 24 for cleaning the optics window 20, a suction port
26 for suctioning body fluids, and an inflation port 28 for
inflating body cavities so that the walls of the cavities may be
more easily examined. The optics window 20 encloses an imaging
system (not shown) and an illumination system (not shown). The
imaging system may be either video or fiberoptic, i.e., either a
miniature television camera of a set of aligned optical fibers. The
illumination system may be either electrical or fiberoptic, i.e.,
an electrically powered light or an optical fiber that receives
light externally.
The insertion tube 14 is an elongated, flexible noncollapsible tube
that contains a biopsy channel (not shown) communicating with the
biopsy port 22, a water channel (not shown) communicating with the
water nozzle 24, a suction channel (not shown) communicating with
the suction port 26, and an inflation channel (not shown)
communicating with the inflation port 28. The insertion tube 14
also contains wires for communicating with a television camera and
light if a video imaging system is used or, alternatively, optical
fibers terminating at the optics window 20 if a fiberoptic imaging
system is used. Finally, the insertion tube 14 contains control
cables (not shown) extending between the control handle 16 and the
tip portion 12. As explained below, the control cables bend the tip
portion 12 as desired to point the optics window 20 in the desired
direction.
The control handle 16 performs several functions. In the event that
a fiberoptic imaging system is used, the optical fiber terminates
at an eyepiece 30 through which the clinician can view an image of
the tissue in front of the optics window 20. The control handle 16
also includes a connector (not shown) for connecting a light source
to the illuminating optical fiber extending to the optical window
20. If a video imaging system is used, the control handle 16
normally includes an electrical connector (not shown) for applying
the television signal to a monitor and for powering the light
behind the optics window 20. The control handle 16 also includes a
manually actuatable valve 32 for the suction channel and a single
manually actuatable valve 34 for both the inflation channel and the
water channel. The control handle 16 also includes ports for these
channels and for the biopsy channel. The control handle 16 also
includes several controls, designated collectively as 40, that
control the bending of the tip portion 12, as mentioned above. Each
of the controls 40 retracts one control cable while extending an
opposite control cable. As mentioned above, the control cables
extend through the insertion tube 14 and terminate in the tip
portion 12. The control cables 40 are arranged so that retracting
one cable while allowing another cable to extend bends the tip
portion 12 in the direction of the retracted cable. Conventional
endoscopes generally include two controls 40 in the form of
concentric wheels. One control 40 bends the tip portion 12 up and
down while the other control 40 bends the tip portion 12 right and
left.
It is important to note that the conventional endoscope 10
illustrated in FIG. 1 is radially symmetric. This radial symmetry
allows the endoscope 10 to have uniform control characteristics
regardless of the direction in which the tip portion 12 is
directed. In other words, the torque and rotation angle required to
rotate the up-down control to bend the tip portion 12 up by a
predetermined amount can be the same as the torque and rotation
angle required to rotate the right-left control to bend the tip
portion 12 to the right by that same amount.
In operation, the clinician advances the tip portion 12 into a body
cavity, such as the stomach or colon. The cavity is then inflated,
if it is desired to make the walls of the body cavity more visible,
by actuating the valve 34 communicating with the inflation channel.
The clinician can then examine the walls of the cavity by
manipulating the controls 40 to point the optics window 20 in any
desired direction. If the window 20 becomes covered with blood,
etc., during the examination, the valve 34 communicating with the
water channel is actuated to spray water from the nozzle 24. Also,
if the clinician desires to withdraw fluid from the body cavity,
the valve 32 communicating with the suction channel is actuated. If
the clinician wants to biopsy the wall of the body cavity or
perform a surgical procedure, an appropriate instrument is inserted
through the biopsy channel and out through the biopsy port 22 so
that it can be viewed through the optics window 20 while performing
the biopsy or other procedure.
It is readily apparent that the endoscope 10 will become
contaminated during the above-described procedure. Further, the
contamination will occur not only on the outside of the endoscope,
but it will occur also in the biopsy, suction and possibly other
channels that are internal to the endoscope. Those internal
channels are extremely difficult, if not impossible to adequately
clean, even if a great deal of time and effort are devoted to the
cleaning procedure. Further, the chemicals used to perform the
cleaning can damage the endoscope, they are fairly expensive, and
they can be toxic to the patient if significant residue remains
after the cleaning.
In order to avoid these contamination and cleaning problems, a
disposable endoscope sheath was developed, as described in U.S.
Pat. No. 4,646,722. Although conventional endoscopes could be
easily adapted for use with the disposable endoscope sheath, the
resulting endoscope would be less than ideal for a number of
reasons. The endoscope would not have the "feel" and uniform
control characteristics of conventional endoscopes, primarily
because the groove formed in the endoscope for receiving the biopsy
channel of the sheath would the destroy the radial symmetry. Also,
merely placing a groove in a conventional endoscope, might cause
the groove to collapse to some extent under certain bending
configurations.
One embodiment of an endoscope that has been specially adapted for
use with a disposable endoscope sheath is illustrated in FIG. 2.
The endoscope 60, like conventional endoscopes, includes a tip
portion 62, an insertion tube 64, and a control handle 66. An
elongated, generally U-shaped groove 68 extends along the length of
the insertion tube 64 and the tip portion 62. The groove 68
receives the biopsy channel 70 (and, if desired, water, suction and
inflation channels) formed in a disposable sheath 72 that surrounds
the endoscope 60. The end of the sheath 72 includes an optical
window 74 for an imaging system and an illuminating system in the
tip portion 62 of the endoscope 60. As with conventional
endoscopes, the imaging system may be either video or fiberoptic.
Similarly, the illuminating system may be either electrical or
fiberoptic. The endoscope 60 also includes a set of control cables
(not shown) extending through the insertion tube 64 from the tip
portion 62 to the control handle 66 for selectively bending the tip
portion 62 as desired. The control cables are operated by
conventional controls 80 mounted on the control handle 66. The
control handle 66 also includes a conventional eyepiece 82,
assuming that a fiberoptic imaging system is used. The control
handle 66 is very similar to the control handles of conventional
endoscopes. The major difference is that the normal valve
arrangement of conventional endoscopes cannot be used since the
channels communicating with those valves do not extend through the
endoscope 60. Instead, in the event that the sheath includes
channels in addition to the biopsy channel 70, the channels will
extend to an external valve mechanism of conventional design.
The endoscope 60, illustrated in FIG. 2, can most advantageously be
used with a disposable endoscope sheath if it satisfies a number of
optimum design goals. These goals are: relatively small diameter
(less than 2.0 cm in diameter); flexibility (radius of curvature of
3 cm); space inside for up to four control cables to control the
bending of the tip section 12; protected space for the imaging
system (fiberoptic or video); protected space for illuminating
system; torque stability; strength to resist compression and
distortion; and a groove 68 along its length large enough to
receive multiple channels (usually air, water, suction and biopsy)
yet constructed so that it will not collapse when the endoscope
bends.
The construction of the inventive endoscope 60 is shown in greater
detail in FIG. 3. The optical components of the endoscope, shown
here as a set of aligned optical fibers 90 and an illuminating
optical fiber 92, extend through a D-shaped flexible tube 94. The
components 90, 92 may also be an electrical cable extending to a
miniature television camera behind the optics window 74 and a pair
of electrical conductors extending to a light mounted behind the
optics window 74. The D-shaped tube 94 is preferably formed of at
least three concentric helical coils 96, 98, 100 of thin,
springsteel ribbons, as illustrated in FIG. 4. Adjacent coils are
wound in opposite directions so that the inner coil is wound in a
helical direction, the middle coil is wound is an antihelical
direction, and the outer coil is wound in a helical direction.
Winding the coil in this manner gives it excellent torque stability
and allows the layers to slide over each other without the edges of
adjacent layers catching each other when the tube 94 is bent. The
resulting cylindrical tube 102 is very strong and flexible.
The D-shaped tube 94 is formed from the cylindrical tube 102 using
a conventional press, as illustrated in FIG. 5. As is well known in
the art, the press includes a lower, stationary press member 110
and an upper press member 112 that moves downwardly toward the
lower member 110 with a great deal of force. An elongated flat bar
114 is mounted on the lower end of the upper press member 112, and
an elongated die 116 containing a semicircular cutout 118 is placed
on the lower press member 110. The circular tube 102 is placed in
the circular cutout, and the upper press member 112 is lowered
until the bar 114 has flattened the cylindrical tube 102 so that it
then becomes a D-shaped tube 94. In this configuration, the tube 94
maintains all of the essential characteristics including
flexibility, torque stability, and strength, found in the
cylindrical tube 102.
Returning now to FIG. 3, the D-shaped tube 94 is placed inside the
lower portion of a tube 120 of wire braid or mesh. An elongated
groove 122 is then formed in the upper portion of the braided tube
120, and the tube 120 is coated with a suitable polymer coating
124. The polymer coating 124 seals the braided tube against
moisture, and it controls the flexibility of the endoscope. More
specifically, the flexibility of the endoscope is controlled by the
durometer and thickness of the polymer coating 124.
It is important to note that the bottom of the groove 122 contacts
the upper surface of the D-shaped tube 94. This configuration
allows the noncompressive characteristic of the D-shaped tube to
prevent the groove 122 from narrowing and elongating (i.e.,
becoming deeper) when the endoscope is bent in a direction
transverse to the plane of the groove (i.e., to the right or left,
as shown in FIG. 3). The D-shaped tube 94 thus functions to
stabilize the shape of the groove 122.
The D-shaped tube 94 and the groove 122 form two channels 130, 132
inside the braided tube 120 on either side of the groove 122. Each
of these channels 130, 132 houses a pair of flexible tubes 134, 136
and 138, 140, respectively. These tubes 134-140, like the
cylindrical tube 102 described above with reference to FIG. 4, are
formed from one or more coils of helically wound wire ribbon.
However, they are small in diameter in order to fit into the
channels 130, 132, and they are either left round or slightly
deformed to conform to the shape of the channels 130, 132. The
tubes 134-140 house cable covers 142 and control cables 144 that
are used to control the bending of the tip portion 62, as described
above. In addition to housing the control cable 144, the tubes
134-140 also strengthen the endoscope and help retain the shape of
the groove 122 since it is not possible to compress the sides of
the groove 122 in a vertical manner with the tubes 134-140 in
place. To further stabilize the shape of the endoscope, all or part
of the channels 130, 132 around the tubes 134-140 can be filled
with a flexible polymer 146, such as silicone. Filling the channels
130, 132 in this manner can improve localization of the inner
components and improve the compressive strength of the overall
assembly.
As explained above, the tubes 134-140 stabilize the shape of the
endoscope and groove 122 for bending of the endoscope in the plane
of the groove 122 (i.e., up and down in FIG. 3), while the D-shaped
tube 94 stabilizes the shape of the endoscope and the groove 122
for bending transverse to the plane of the groove. However,
additional stabilization may be desirable in order to keep the
braided tube 120 from pulling away from the apexes of the D-shaped
tube 94 responsive to transverse bending. The endoscope is
preferably stabilized for transverse bending by weaving a fine wire
150 back and forth along the length of the endoscope. The wire 150
holds in the sides of the braided tube just above the diameter of
the D-shaped tube 94. The wire 150 could also extend back and forth
between the tubes 134, 138 in the channels 130, 132. Alternatively,
stabilization against transverse bending could be provided by using
a suitable adhesive to bond the braided tube 120 to the D-shaped
tube 94.
An alternative embodiment, illustrated in FIG. 6, is similar to the
embodiment of FIG. 3 in that it also uses a D-shaped tube 94
surrounded by a braided tube 120 (FIG. 3) in which a groove 122 is
formed and the tube 120 is covered with a polymer coating 124.
However, the embodiment of FIG. 6 utilizes a plurality of
longitudinally spaced ribs 170 attached, such as by welding, to the
apexes of the D-shaped coil 94. The ribs 170 have the desired shape
of the upper portion of the endoscope, including the groove 122,
and they provide rigid side walls for the groove 122. The ribs are
preferably fabricated from steel so that they are sufficiently
strong to prevent vertical compression of the grooves 122 as well
as lateral expansion of the endoscope with bending. Flexibility is
controlled by the spacing between the support ribs 170. The support
ribs 170 do not contribute to flexibility or torque stability of
the endoscope, but they add significantly to the overall strength
and non-collapsibility of the endoscope.
With reference to FIG. 7, a slight variation of the embodiment
illustrated in FIG. 6 utilizes ribs 172 that have lower portions
that are cylindrical in shape such that they wrap around the
D-shaped tube 94. The ribs 172 may float on the D-shaped tube 94,
or they may be bonded to either the D-shaped tube 94 or to the
braided tube 120.
With reference to FIG. 8, still another embodiment of the invention
utilizes a formed helical coil 180 that is wrapped around the
D-shaped tube 94. The coil 180 can be attached to the tube 94 or it
can free float on the tube 94.
The inventive endoscope thus has a groove along its length so that
it can be used with a disposable sheath as described in U.S. Pat.
No. 4,646,722, yet it is flexible, strong and torque stable.
Furthermore, it operates in the same manner and with the same
"feel" as conventional endoscopes, and it has uniform control
characteristics in all directions.
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