U.S. patent application number 10/901252 was filed with the patent office on 2006-02-02 for autoclavable endoscope.
Invention is credited to Martin Uram.
Application Number | 20060025655 10/901252 |
Document ID | / |
Family ID | 35733269 |
Filed Date | 2006-02-02 |
United States Patent
Application |
20060025655 |
Kind Code |
A1 |
Uram; Martin |
February 2, 2006 |
AUTOCLAVABLE ENDOSCOPE
Abstract
An autoclavable endoscope, such as the type used in
ophthalmological operations, has a probe that contains optical
fiber guides such as an image guide, a laser guide and an
illumination guide. The distal end of these guides are sealed to
the distal end of the probe with a high temperature medical grade
epoxy. The epoxy is selected to retain its structural and optical
properties at autoclaving conditions. A preshrunk flexible plastic
jacket extends proximal of the handle around the three guides.
Because it is preshrunk at autoclavable temperatures, it is not
further damaged during autoclaving. The epoxies used proximal to
the probe have to be high temperature epoxies but are generally
preferably a more flexible urethane type epoxy. Proximal connectors
and ferule for the guides are selected metals to retain size and/or
conduct heat.
Inventors: |
Uram; Martin; (Little
Silver, NJ) |
Correspondence
Address: |
REED SMITH, LLP;ATTN: PATENT RECORDS DEPARTMENT
599 LEXINGTON AVENUE, 29TH FLOOR
NEW YORK
NY
10022-7650
US
|
Family ID: |
35733269 |
Appl. No.: |
10/901252 |
Filed: |
July 27, 2004 |
Current U.S.
Class: |
600/133 ;
600/121; 600/132; 600/182 |
Current CPC
Class: |
A61B 1/042 20130101;
A61B 1/0011 20130101; A61B 1/0017 20130101; A61B 2090/0813
20160201; G02B 23/2492 20130101 |
Class at
Publication: |
600/133 ;
600/132; 600/182; 600/121 |
International
Class: |
A61B 1/00 20060101
A61B001/00 |
Claims
1. In an autoclavable endoscope having a probe with a sidewall
containing at least an optical fiber illumination guide and an
optical fiber image guide and wherein the distal end of the image
guide contains a cylindrical cannula within which is positioned a
window at the distal end of the cannula, an objective lens having
first and second lens elements proximal to and adjacent to the
window and image guide fiber proximal and adjacent to the proximal
one of the lens elements, and a handle proximal to the probe, the
improvement comprising: a preshrunk flexible plastic jacket
extending proximal of the handle and encompassing said optical
guides, a trifurcation zone at the proximal end of said jacket from
which zones said guide extend proximally, a first type epoxy
bonding the distal ends of said guides to said probe, said first
epoxy also bonding the circumference of the distal lens element and
the circumference of the window to the cylindrical cannula at the
end of the image guide, a second type epoxy bonding the proximal
lens element to the cannula, a third type epoxy bonding said jacket
to the optical guides at said trifurcation, said first type epoxy
being a medical grade, high temperature resistant, overnight
setting epoxy which retains its structure and optical properties at
autoclaving conditions, said second type epoxy being a high
temperature grade, more rapidly setting epoxy which retains its
structural and optical properties at autoclaving temperature, said
third type epoxy being a high temperature, flexible epoxy, said
first type epoxy preventing steam from reaching and contaminating
the lens during autoclaving, said jacket being preshrunk at
autoclaving conditions to minimize jacket shrinkage during
autoclaving of the endoscope, a first metal connector at the
proximal end of the light guide, said connector including a high
heat conductivity metal ferule bonded to the light fibers by said
second type epoxy, and a second metal connector at the proximal end
of the image guide.
2. The improvement of claim 1 wherein: said metal ferule in said
light guide connector is copper.
3. The improvement of claim 1 wherein: said first and second metal
connectors are aluminum.
4. The improvement of claim 2 wherein: said first and second metal
connectors are aluminum.
5. The improvement of claim 1 wherein: said third type epoxy bonds
the jacket to the hand piece and to all connectors.
6. The improvement of claim 2 wherein: said third type epoxy bonds
the jacket to the hand piece and to all connectors.
7. The improvement of claim 3 wherein: said third type epoxy bonds
the jacket to the hand piece and to all connectors.
8. The improvement of claim 4 wherein: said third type epoxy bonds
the jacket to the hand piece and to all connectors.
9. The improvement of claim 1 wherein: the light connector is
bonded to the light fibers by an epoxy selected from said first and
second types.
10. The improvement of claim 4 wherein: the light connector is
bonded to the light fibers by an epoxy selected from said first and
second types.
11. The improvement of claim 7 wherein: the light connector is
bonded to the light fibers by an epoxy selected from said first and
second types.
12. The improvement of claim 8 wherein: the light connector is
bonded to the light fibers by an epoxy selected from said first and
second types.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates in general to a design that makes
possible the autoclaving of a fiberoptic endoscope used for medical
purposes.
[0002] One application of this invention is to an endoscope used in
certain ophthalmologic operations. The disclosure herein relates to
that embodiment.
[0003] As shown, for example, in Applicant's U.S. Pat. No.
5,121,740 issued Jun. 16, 1992, it is known to provide an endoscope
which may contain an optical fiber illumination guide, an optical
fiber laser guide and an optical fiber image guide to perform
surgical operations in various parts of the eye.
[0004] It is important that such an endoscope, as well as other
types of endoscopes used for other surgical operations, be
sterilized between each use or, if that cannot be satisfactorily
done, disposed of after first use.
[0005] In some venues, it is acceptable to employ a high level
disinfectant after the use of the endoscope so that it can be
reused. In other venues, only the autoclaving under known high
temperature steam conditions is acceptable.
[0006] An endoscope such as the type described in U.S. Pat. No.
5,121,740 cannot be autoclaved and reused. Essentially, when
autoclaved, the known endoscopes tend to lose their critical
optical characteristics and do not provide the clear and focused
image that is required for a surgical operation.
[0007] Accordingly, it is a primary purpose of this invention to
provide an endoscope design which can be autoclaved so that the
endoscope can be reused.
[0008] It is a further object of this invention that this
autoclavable endoscope be provided at a cost which makes it cost
effective to use compared to the presently available
non-autoclavable endoscopes.
[0009] It is a related purpose of this invention to provide an
autoclavable endoscope with a configuration and utility that
sufficiently resembles that of the prior art non-autoclavable
endoscopes so that its use will be familiar and comfortable for the
surgeon or physician.
BRIEF DESCRIPTION
[0010] In brief, in the embodiment of this invention disclosed
herein, a known type of a three optical guide endoscope is provided
in which there is a laser fiber guide, an illuminating fiber guide
and an image fiber guide.
[0011] These three light guides are attached at proximal ends, to
respectively a laser connector, a xenon light source connector and
a camera connector.
[0012] The three optical guides attached to these connectors are
brought together into a single flexible jacket. At the distal end
of the jacket, they are brought through a hand piece to a probe,
which probe is a stainless steel cylinder. This cylinder is
effectively a hypodermic needle having an outer diameter of, for
example, 960 microns (0.96 mm).
[0013] Autoclaving is at 265 degrees F. for 15 minutes. The
features that make this design autoclavable are as follows:
[0014] The epoxies used at the distal end to seal all three optical
systems to the stainless steel probe and to seal the protective
window and lens of the system within the distal end of the image
guide are high temperature resistant, medical grade epoxies.
[0015] It is particularly important that the specific epoxy used on
the lens which is focused is one that can be cured in a relatively
short period of time (15 to 30 minutes) so that the focus
established can be permanently set. Since the lens to be focused is
proximal of the window and companion lens, that epoxy need not be
medical grade.
[0016] A third feature is in the use of a preshrunk thermoplastic
elastomer jacket material to enclose the three optical systems
throughout the flexible zone proximal of the hand piece. The
preshrinking of this material minimizes its dimensional change
during autoclaving. The term preshrunk herein refers to
preshrinking at high temperature.
[0017] A fourth feature relates to an appropriate construction of
the connector at the proximal end of the light fiber. The light
fiber portion of the light guide is sealed to a copper ferule with
a high temperature epoxy that retains its structure under high
temperature to minimize injury of the fragile light fiber system,
which injury occurs if the epoxy melts or runs. The material of the
ferule is copper so as to dissipate the heat from the xenon light
source. This will further serve to minimize injury to the fragile
light fiber system. The copper ferule is within an aluminum
connector.
[0018] The camera connector, which in the prior art is a plastic
material, is replaced by anodized aluminum. This avoids swelling
during autoclaving. It is a necessary change to make sure that
after autoclaving the connector will couple into the socket of a
camera.
[0019] In addition, all epoxies used are high temperature resistant
to withstand the 15 minutes at 265.degree. F. autoclaving
regimen.
BRIEF DESCRIPTION OF THE FIGURES
[0020] FIG. 1 is a schematic illustration of the endoscope
extending from distal probe 10 to proximal connectors 12C, 14C,
16C.
[0021] FIG. 2 is a longitudinal sectional view through the image
cannula 30 at the distal end of the endoscope. FIG. 2 is at a much
greater scale than that of FIG. 1.
[0022] FIG. 3 is a cross-sectional view through the probe 24 at the
juncture between the quartz window 32 and the lens 28. FIG. 3
illustrates the reticule 34 that creates the aperture step 36.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] The FIGS. illustrate a single embodiment. This endoscope 10
has three main optical guides. They are a laser fiber guide 12, a
set of fibers to provide a light guide 14 and an image guide 16
having approximately 10,000 light elements to provide 10,000
pixels. These three optical guides 12, 14 and 16 are held in a
plastic jacket 18. This jacket 18 extends from a trifurcation zone
20 to the hand piece 22 near the distal end of the endoscope
10.
[0024] Distal of the hand piece 22 is the stainless steel
cylindrical probe 24. The three light guides 12, 14, 16 extend
through the probe 24 and are flush with the distal end of the probe
24.
[0025] Proximal of the trifurcation zone 20, the three optical
guides are in three separate jackets extending to appropriate
connectors 12C, 14C, 16C of the optical systems to a laser, a light
source and a camera, respectively.
[0026] Specifically, connector 12C at the distal end of the laser
fiber guide 12 permits coupling to a laser. A connector 14C at the
proximal end of the light fiber guide 14 permits connecting to a
xenon light source and a connector 16C at the distal end of the
image guide 16 permits connection to a camera.
[0027] The fibers of the laser fiber guide 12 and light fiber guide
14 extend flush to the distal end of the probe. However, the fibers
of the image guide 16 extends to the point where they contact the
compound lens that consists of a first lens element 26 and a second
lens element 28 (see FIG. 2).
[0028] One of the features that makes an endoscope not autoclavable
is that steam enters around and between the two lenses 26, 28
thereby changing the optical properties and degrading the image
involved. Therefore, it becomes important that particular attention
be made to the design at the distal end of the image guide 16.
[0029] A thin wall stainless steel cannula 30 surrounds and
supports the distal end of fibers of the image guide 16. At the
distal end of this cannula 30, is a transparent protective quartz
window 32. The window 32 is immediately distal of the two lenses 26
and 28. The lens 26 is epoxy bonded to the distal end of the fibers
of the image guide 16. The spacing between the lenses 26 and 28, as
well as the spacing between the lens 28 and the window 32 are only
enough to prevent chromatic aberration. The lens 28 and the window
32 are sealed along their peripheries to the cannula 30 by a high
temperature resistant epoxy. FIG. 3 illustrates the reticule 34
that creates the aperture stop 36 for the image that is to be
collimated by the lens system 26, 28.
[0030] FIG. 3 shows the light fiber bundle in a geometric state
which is distal of the hand piece 22. Proximal of the hand piece,
the light fiber bundle is a more coherent bundle with a circular
cross-section having its own separate geometry and is within its
own jacket. But in order to achieve as small a probe as possible,
it is more efficient for the light bundle to be distributed in the
fashion shown in FIG. 3.
[0031] The autoclavable endoscope 10 of this invention is made
possible by a selection and treatment of materials which in
combination permit autoclaving without deterioration of operating
characteristics. It should be understood that the endoscope of this
invention is not indefinitely autoclavable. That is, after it has
been autoclaved a number of times (for example, a dozen times), its
operating characteristic may degrade and can no longer be used. The
key characteristics that normally degrade initially are the focus
or clarity of the image provided by the image guide 16 and/or the
loss of light due to the breakdown of epoxy at the connector 14C
for the light guide.
[0032] Applicant believes that the invention involved herein is
primarily in the selection of materials (and importantly, the
particular epoxies) that are subjected to an autoclaving
temperature of 265 degrees F., a temperature which is close to the
temperature limit at which these epoxy materials retain their
sealing and transparency characteristics.
[0033] With this invention, it becomes possible, at reasonable cost
and without material change in the manner of operation of the
endoscope, to provide a device which can be autoclaved a number of
times.
[0034] In large part, this invention is a trade-off between: (a)
maintaining reasonable cost, (b) providing an autoclavable
endoscope, and (c) providing an endoscope that operates
substantially in the same fashion as do comparable endscopes known
to the profession.
[0035] As part of this trade-off, that there is an economic
trade-off between: (a) the cost of the non-autoclavable endoscope,
(b) the cost of the autoclavable endoscope of this invention and
(c) the number of times at which the endoscope of this invention
can be autoclaved. Applicant believes that this invention provides
a combination which optimizes these trade-offs.
[0036] A significant epoxy is the one employed at the distal end of
the probe 24 to seal in the three light guides 12, 14 and 16 and
also to seal the distal lens element 28 and quartz window 32 to the
cannula 30. It is a high temperature resistant, overnight setting,
medical grade epoxy. This high temperature resistance requires both
that it not melt during the autoclaving process and that it retain
a substantial transparent characteristic before and after
autoclaving. An epoxy has been identified which maintains its color
and geometry when subjected to the autoclaving process. This epoxy,
when subject to autoclaving, is effectively pushed to its limit.
Applicant believes this is a reason why this autoclavable endoscope
can only be autoclaved a limited number of times; for example,
twelve to fifteen times, before losing its image definition and
clarity.
[0037] A second epoxy seals the proximal lens element 26 to the
cannula 30. It is a high temperature epoxy which has a faster
setting time than does the epoxy used for sealing the three light
guides to the probe 24. It sets in 15 to 20 minutes at 166 degrees
F. It also maintains its geometry and optical transparency during
autoclaving. It need not be medical grade.
[0038] Both of the above epoxies are selected for the optical
characteristic that they are not black and are transparent or amber
and maintain this optical characteristic after autoclaving. The
transparency of the epoxy is important to assure non-interference
with the transmission of light.
[0039] By contrast, the epoxy at the trifurcation 20 and proximal
end of the three systems is generally preferably a more flexible
epoxy such as a urethane. The urethane can be black in color and
need not be medical grade. However, such epoxy must withstand the
autoclaving temperature and time.
[0040] A further feature is that the thermoplastic elastomer jacket
18 is pre-shrunk at autoclaving temperature to prevent it from
being damaged during autoclaving.
[0041] It is further important that the prior art plastic connector
16C to the camera is replaced by anodized aluminum to prevent
swelling during autoclaving so that it can be reused and will fit
into the camera socket. The epoxy used to bond the image guide
fibers and ferule to the aluminum connector 16C is not as critical
as some of the other epoxies and may be a standard epoxy.
[0042] Another important feature is that the ferule within the
connector 14C for the light guide be of copper so as to dissipate
the heat from the xenon light source. The connector 14C shell is
aluminum. A high temperature epoxy such as that used to bond the
lens 26 to the cannula 30 is used to bond the light fibers to the
ferule. The copper ferule and epoxy used at the ferule minimize
damage to the delicate fibers used for this illumination guide.
[0043] In particular, in one embodiment of the invention, the probe
24 is a 33 mm long stainless steel cylinder with an OD of 960
microns and an ID of 880 microns. The stainless steel cannula 30 is
a 24 gauge cylinder having a 570 micron (0.57 mm) outside diameter,
a 520 micron inside diameter and a length of 331 microns. Within
the cannula 30, there is the two element 26, 28 compound lens and
the transparent quartz window 32. The quartz window 32 is 250
microns long, the lens element 26 is about 590 microns and the lens
element 28 is approximately 370 microns. The three elements 26, 28
and 32 are longitudinally spaced from one another only enough to
avoid chromatic aberration. Thus, the spacing is in the range of a
fraction of a micron. The fiber optic bundle for the image system
16 extends through into cannula 30 and is bonded to the proximal
surface of the lens element 26. The surface of the quartz window 32
is essentially flush with the end of the cannula 30 and the end of
the probe 24. The lens elements 26 and 28 as well as the window 32
are held in place by a full circular epoxy band. This epoxy band
extends over about the proximal 150 microns portion of the window
32 and also over about 250 microns of the distal portion of the
lens element 28. This full circular epoxy band which binds the
elements 28 and 32 to the inner surface of the cannula 30 wall
serves to prevent steam under the pressures and temperatures of
autoclaving from getting into the spaces between the lens and
window elements 26, 28 and 32.
[0044] In one embodiment that has been tested, the following have
been successfully employed.
[0045] A first epoxy that is used to bond the guides 12, 14 and 16
to the probe 24 is a Master Bond 42HT MED available from Master
Bond, Inc. of 154 Hobart Street, Hackensack, N.J. 07601. This epoxy
sets over night in approximately twelve hours at room temperature.
This epoxy is also used to bond the lens 28 and window 32 to the
cannula 30.
[0046] In fabrication, the lens 26 is used to establish the focus.
Thus the epoxy that bonds the lens 26 to the cannula 30 has to be
one that sets more quickly than does the 42HT MED. The epoxy used
is an EPOTEK 353ND-T epoxy available from Epoxy Technology. Inc. at
14 Fortune Drive, Billerica, Mass. 01821. Under a heat lamp at
1660.degree. F., it cures in between 15 to 20 minutes. This
provides a useful setting time within which to establish the focus
and obtain a permanent set.
[0047] Both of the above epoxies have properties which allow them
to withstand 265.degree. F. for 15 minutes for a limited number of
times without significantly changing their structural and light
transparency properties.
[0048] Another area where the selection of epoxies has to be
carefully chosen is at the connector end of the endoscope. A Master
Bond 43HT Medical epoxy can be used to bond the laser guide 12
fiber to the laser connector 12C as well as to bond the light guide
14 fiber to a ferule that is in the connector 14C. In the latter
case, for convenience in terms of available oven, applicant has
also used the EPOTEK 353 ND-T.
[0049] The high temperature created by the laser at the laser
connector 12C and by the xenon light source at the light guide
connector 14C requires the use of epoxies that withstand not only
the autoclaving temperature but the temperature from the light
sources when the endoscope is in use.
[0050] A HYSOL 608 standard epoxy has been used at the image guide
to bond the image fiber to a ferule which in turn is bonded to the
connector 16C. This epoxy primarily has to be able to withstand the
autoclaving temperature without substantial physical distortion. It
is available from Loctite Corp. in Rocky Hill, Conn. 06067.
[0051] At other locations, such as when bonding the ferule to the
light guide connector 14C and the ferule to the image guide
connector 16C, the jackets of the guides of all three connectors,
bonding at the trifurcation 20 and bonding of the jacket to the
hand piece 22, a double bubble urethane epoxy D85 has been used. It
is available from Elements Specialties, Inc. of Belleville, N.J.
07109. It has the advantages of bonding well to plastic and not
melting at the autoclaving temperatures.
[0052] While the foregoing description and drawings represent the
presently preferred embodiments of the invention, it should be
understood that those skilled in the art will be able to make
changes and modifications to those embodiments without departing
from the teachings of the invention and the scope of the
claims.
[0053] For example, the invention has been described in connection
with an endoscope having three different fiberoptic systems. Yet,
it could be employed with an endoscope having the illumination
guide and image guide without the laser guide.
* * * * *