U.S. patent number 3,687,142 [Application Number 05/078,433] was granted by the patent office on 1972-08-29 for catheter.
Invention is credited to Saul Leibinzohn.
United States Patent |
3,687,142 |
Leibinzohn |
August 29, 1972 |
CATHETER
Abstract
A catheter adapted for introduction into difficulty accessible
regions of the human body comprising a catheter tube and a flexible
tube adapted for displacement within the catheter tube and for
protrusion from the distal end of the catheter tube. A radio-opaque
embolus is attached to the distal end of the flexible tube by means
of a flexible thread. When the catheter is inserted into the body
in the vicinity of the required region, the embolus is directed
into the required region by the flow of bloodstream together with
gravity forces, carrying with it the flexible tube. Suitable fluid
can then be injected into the required region through the catheter
and apertures formed in the flexible tube.
Inventors: |
Leibinzohn; Saul (Tel-Aviv,
IL) |
Family
ID: |
22144000 |
Appl.
No.: |
05/078,433 |
Filed: |
October 6, 1970 |
Current U.S.
Class: |
600/435; 600/433;
604/523 |
Current CPC
Class: |
A61M
25/0125 (20130101); A61M 25/0108 (20130101) |
Current International
Class: |
A61M
25/01 (20060101); A61m 025/00 () |
Field of
Search: |
;128/348-351,356,343,240,2M,2.5M,DIG.9,2.5R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truluck; Dalton L.
Claims
I claim:
1. A catheter comprising a catheter tube having first and second
ends with a lumen interconnecting said ends, a flexible tube
carried for longitudinal displacement within the catheter tube and
for protrusion from the first end thereof, an at least partially
radio-opaque embolus, a highly flexible thread interconnecting said
embolus and the end of the flexible tube adapted to protrude from
the catheter tube, said embolus being fixedly attached to said
thread, said catheter tube and said flexible tube being provided
with means for preventing separation of the flexible tube from the
first end of the catheter tube, and displacing means coupled to the
opposite end of the flexible tube for moving it through the
catheter tube so as to free the embolus and flexible tube for
limited longitudinal motion with respect to the catheter tube.
2. A catheter according to claim 1, wherein said displacing means
comprises a stylet wire which extends through the catheter and is
coupled to the inner end of the flexible tube.
3. A catheter according to claim 2, wherein said stylet wire is
spiralled about the inner end of the flexible tube.
4. A catheter according to claim 2, wherein said stylet wire is
coupled to the flexible tube by means of a double collar structure
one component of which is clamped to the end of the flexible tube
and the other component of which is crimped to the end of the
stylet wire.
5. A catheter according to claim 2, wherein said thread extends
through the flexible tube and is secured to the stylet wire.
6. A catheter according to claim 1, wherein said embolus is of
spherical, discoid or cylindrical shape.
7. A catheter according to claim 1, wherein said embolus is formed
of stainless steel.
8. A catheter according to claim 1, wherein said embolus is formed
of platinum.
9. A catheter according to claim 1, wherein said embolus is formed
of a radio-opaque soluble material.
10. A catheter according to claim 1, wherein said embolus is formed
of a deformable hollow material adapted to contain a contrast
medium.
11. A catheter according to claim 1, wherein said flexible tube,
embolus and thread are formed as an integral whole, the embolus
being hollow and being adapted to have a contrast medium introduced
therein via a bore formed in the connecting thread.
12. A catheter according to claim 1, wherein outlet apertures or
slits are formed in the flexible tube.
13. A catheter according to claim 1, wherein said catheter tube is
formed of two parts, said flexible tube being adapted to project
from a first part, and the second part being provided with a valve
inlet means, connecting means being provided for connecting said
two parts together.
14. A catheter according to claim 13, wherein said connecting means
comprises a pair of tubular metal coupling elements having
respectively tapering outer and inner walls adapted to fit one
within the other and to be respectively coupled to said tube
parts.
15. A catheter tube according to claim 13, wherein said connecting
means is provided with a flexible sleeve having a skirt portion
adapted to be clipped so as temporarily to close said one catheter
tube part.
16. A catheter according to claim 13, wherein said valve inlet
means is constituted as a tubular T-piece, having an inlet limb
which communicates via an inlet port with a limb coupled to the
second catheter tube part, means being provided for
unidirectionally closing said inlet port.
Description
This invention relates to a catheter.
According to the present invention there is provided a catheter
comprising a catheter tube, a flexible tube adapted for
displacement in the catheter tube and for protrusion therefrom, an
at least partially radio-opaque embolus attached by means of a
highly flexible thread to that end of the flexible tube adapted to
protrude from the catheter tube and displacing means coupled to the
opposite end of the flexible tube for displacing it through the
catheter tube so as to free the embolus and flexible tube for
limited motion with respect to the catheter tube.
As used in this specification, the term "emobolus" refers to an
artificially constructed body adapted to be introduced into and to
circulate in the blood stream.
The construction and use of the catheter in accordance with the
invention arises out of the discovery that the flow of the
bloodstream itself together with gravity considerations can, under
appropriate circumstances, result in the direction of an embolus,
located in the bloodstream, into a tract in which it will progress
taking with it the flexible tube. Once the flexible tube is located
in the required tract it can be advanced or withdrawn by means of
the displacing means. With the flexible tube located in the
required position the catheter can be employed, for example, for
the introduction of a suitable fluid into the tract, the fluid
being injected through the catheter and being ejected from suitable
apertures formed in the flexible tube. Such a fluid can, for
example, be a contrast fluid for use in radiological examination of
the region. In all cases, the movement of the catheter into the
required tract can be monitored in view of the provision of the
radio-opaque embolus and the precise moment when the embolus enters
the required duct can be determined.
If the embolus has a specific gravity greater than that of the
blood and the tract to be catheterized is directed downwardly, the
combined effect of the bloodstream flow and gravity will result in
the direction of the embolus into this tract. On the other hand, if
the overall specific gravity of the embolus is less than that of
the blood the tendency of the embolus will be to rise and this
tendency together with the blood flow will aid in directing the
embolus into an upwardly directed tract.
The construction and mode of use of a catheter in accordance with
the present invention will be clarified by recourse to the
following description and with reference to the accompanying
drawings in which:
FIG. 1 is a schematic side elevation of the catheter when fully
extended;
FIG. 2 is a longitudinal sectional view on an enlarged scale of a
first detail of the catheter shown in FIG. 1;
FIG. 3 is a longitudinal sectional view on an enlarged scale of a
second detail of the catheter shown in FIG. 1;
FIGS. 4 a, 4 b and 4 c are respective elevational views of three
differing forms of emboli;
FIGS. 5 and 6 are respective views of differing forms of flexible
tube endings;
FIG. 7 is a cross-sectional view of a stylet coupling collar;
FIGS. 8 and 9 are longitudinal sectional views of modified forms of
flexible tubes.
As seen in the drawings, the catheter comprises a pair of standard
catheter tubes 1 and 2, the two tubes being joined together by a
connecting piece 3. The free end of the catheter tube 2 is fitted
with an inlet valve 4, while, as shown in FIG. 1 of the drawings,
there projects from the free end of the catheter tube 1 a flexible
tube 5 which is connected at its projecting end by means of a
highly flexible thread 6 to a radio-opaque embolus 7. A stylet wire
8, shown projecting out of the valve means 4 extends through the
whole length of the catheter and is secured to the inner end of the
flexible tube 5 in a manner to be described below.
Reference will now be made to FIG. 2 of the drawings in which is
shown in detail the mode of connection of the two catheter tubes 1
and 2 and the construction of the flexible tube 5.
As seen in FIG. 2, the catheter tube 1 is provided, at one end,
with an externally directed flange 9 and tapers at its other end to
define an aperture 10. The flexible tube 5 which has a much
narrower diameter than the catheter tube 1 is provided with a
flared end 11 and is secured at its opposite closed end to the end
of the highly flexible thread 6. One or more ejecting apertures 12
are formed in the flexible tube adjacent to its closed end. The
stylet wire 8 is secured to the flared end 11 of the flexible tube
5 by being spiralled therearound, the spiralled end being adapted
to bear against the tapered end of the tube 1 so as to seal it.
The connecting piece 3 comprises a first steel coupling element 13
constituted by a central broad portion 14 and two terminal portions
of smaller diameter 15 and 16. The terminal portion 16 is
externally threaded so as to receive a locking nut 17 which is
provided with an inwardly directed flange arranged to clamp in
position the flange 9 of the catheter tube 1. The coupling element
13 is internally bored, the diameter of the bore being at its
maximum adjacent to the terminal end 15 and at its minimum adjacent
to the terminal end 16. The bore is provided with two tapering wall
portions 18 and 19.
The connecting piece 3 furthermore comprises a second steel
coupling element 21 which consists of a main tubular portion 22
having a tapering conical portion 23 adapted to fit closely within
the tapering bore 18 of the coupling element 13. The main tubular
portion 22 is provided at either end with tubular extensions 25 and
26 of narrower diameter than the main tubular portion 22, with a
uniform bore extending through the entire coupling element 21. The
tubular extension 26 fits within the tubular bore formed in the
coupling element 13 while the other tubular extension 25 is
provided with a couple of ribs 27 on which is fitted the end of the
catheter tube 2. A rubber sleeve 28 surrounds the elements 13 and
21.
Reference will now be made to FIG. 3 of the drawings for a
description of the inlet valve means 4 of the catheter. This inlet
valve means 4 comprises a steel tubular T-piece 31 having a main
body portion 32 and a tubular extension thereof 33 whose extremity
is externally threaded so as to receive a locking nut 34 which
locks in position via a washer 36 an outwardly extending flange 35
of the catheter tube 2 against the outer edge of the tubular
extension 33. The tubular T-piece 31 is furthermore provided with
an inlet duct 37 which communicates with the main bore 38 of the
valve via an inlet port 39. A rubber sleeve 40 whose internal wall
41 tapers is inserted in the main bore 38 so as to seal the port
39. The construction of the sleeve 40 is such that when a fluid
pressure is built up in the catheter and, in consequence, in the
tubular bore 38, this pressure presses the tapering walls of the
sleeve against the port 39 sealing it but when on the other hand
fluid is injected through the duct 37 this fluid is forced into the
bore 38 and therefore into the catheter by pressing away the sleeve
40.
As can be seen in the drawings the stylet wire 8 extends through
the entire catheter and emerges through the bore 42 formed in the
terminal portion of the sleeve 40 and the outlet port 43 of the
T-piece 31.
FIGS. 4a, 4b and 4c show different constructions of emboli. Thus in
FIG. 4a the embolus is completely spherical, in FIG. 4b the embolus
is right cylindrical while in FIG. 4c the embolus is substantially
discoid in shape. While the particular shape of the embolus is not
critical, the discoid construction has been found in practice to be
preferable, it being less likely to become undesirably lodged
during catheterization in the tract. Furthermore with a flat
discoid shape the embolus in movement offers a relatively large
area for radiological detection with minimal risk of blocking the
tract.
As seen in the drawings, the end of the stylet wire 8 is coupled to
the end of the flexible tube by being wound therearound. In order
to ensure that the coupling is effective the end of the flexible
tube should be appropriately formed. As seen in FIG. 5 the end of
the flexible tube is provided with an outwardly extended flange 45.
This flange 45 is of thickened construction thereby strengthening
the end of the flexible tube. As seen in FIG. 6 of the drawings,
the end 46 of the flexible tube is flared and is provided with a
correspondingly flared stiffening portion 47.
FIG. 7 illustrates an alternative mode of coupling the stylet wire
8 to the flexible tube 5. In accordance with this construction a
two-piece collar construction 48 is employed; the first collar
portion 49 is firmly clamped around the end of the flexible tube
while the second collar portion which is connected to the first by
the common wall strip 50 is firmly crimped around the end of the
stylet wire 8.
FIG. 8 illustrates a slightly modified construction in which the
thread 6' does not terminate at the end portion of the flexible
tube 5 but extends through the flexible tube 5 and out thereof so
as to be secured to a looped portion 51 of the stylet wire 8
adjacent to its place of coupling to the flexible tube 5. The
purpose of this modification is to ensure that, in the event that
the flexible tube breaks in use the parts thereof will remain
attached to the thread 6' which is of considerable tensile
strength. In this way there is avoided the danger of parts of the
catheter remaining in the tract.
FIG. 9 shows a still further modified form of a flexible tube 55
which is formed integrally with the embolus 56 and connecting
thread 57. In this case the embolus is formed as a hollow structure
into which is introduced, via a very narrow bore formed in the
thread 57 a contrast liquid thereby rendering the embolus
radio-opaque. In other respects the flexible tube 55 is constructed
similarly to the flexible tube 5 previously described.
As previously indicated, the embolus is formed of a radio-opaque
material. Suitable material can, for example, be heavy
non-corrosive metals such as platinum, stainless steel or the like.
Alternatively, the embolus can be constituted by a soluble
material, e.g., gelatine mixed with a suitable contrast material.
In this case the embolus remains in the tract for the period
necessary for catheterization after which period solution takes
place.
A still further alternative is to form the embolus of a deformable
material, for example a rubber balloon, which contains the liquid
contrast material Such a possibility is envisaged in connection
with the embodiment shown in FIG. 9 where the embolus is formed
integrally with the flexible tube. A still further possibility is
forming the embolus of lead oxide, which has been bonded together
by means of a suitable bonding material.
Where the embolus is to enter a downwardly directed tract the
specific gravity of the embolus must be greater than that of the
blood and no problem is encountered when such an embolus is
radio-opaque. Where however, the embolus is to enter an upwardly
direct tract, the embolus must be capable of floating in the
bloodstream and for this purpose the overall specific gravity of
embolus must be less than that of the blood. This requirement must
be reconciled with that of radio-opacity and this is achieved by
distributing throughout the embolus radio-opaque material.
The thread used to attach the embolus to the flexible tube can, for
example, be formed of silk. A still better possibility is the use
of a nylon thread in view of its invariant physical
characteristics, especially in liquid. The length of the thread can
vary from 1 to 4 centimeters.
The stylet is preferably formed of steel having a diameter of
between 0.2 to 0.6 mm.
The flexible tube is made of a highly flexible material, which is
resistant to the media into which it is introduced. The tube in
addition to its high flexibility must have a very thin wall and a
high tensile strength. Suitable materials may include, latex,
silicon rubber or a suitable plastic material. The internal
diameter of the tube can vary from about 0.6 to 2 mm while the wall
thickness thereof can vary from 0.05 to 0.5 mm. Different lengths
of flexible tubes can be employed ranging from 5 to 15 cm.
In accordance with a specific modification the flexible tube is so
shaped as to be capable of flexing in a preferred direction. This
can be achieved e.g., by shaping the tube so that over the major
portion of its length it is of relatively flat cross-section, it
becoming circular only in the region of its mouth. Such a
construction ensures a preferred direction of flexing of the tube
and therefore facilitating its entry into a tract located in that
preferred direction.
While, as indicated above, the fluid is ejected from the flexible
tube through apertures, slits can equally well be formed in the
flexible tube for the ejection of the fluid.
The mode of assembly and use of the catheter described above will
now be explained:
The catheter tube 1 secured to the coupling element 13 is
arterially introduced by any known standard method into the region
of the tract to be catheterized. After introduction, the catheter
tube is closed against outflow of blood by clipping the skirt
portion of the rubber sleeve 28. When catheterization is proceeded
with the second catheter tube 2, which is connected to second
coupling element 21 and which is loaded with the flexible tube and
embolus, is coupled to the first tube by the insertion of the
second coupling element within the first coupling element, the
skirt of the rubber tube then embracing the second coupling
element. With the catheter tube 1 suitably inserted and connected
to the catheter tube 2, the flexible tube 5 and the embolus 7
attached to the tube by the flexible thread 6 is pushed forward
from the catheter tube 2 in which it was contained by means of the
stylet 8 which projects out of the valve means 4. As can be seen in
FIG. 2 of the drawings when the flexible tube has been fully
projected out of the catheter tube, the spiralled end of the stylet
effectively seals the mouth 10 of the catheter tube and fluid
injected through the catheter passes through the flexible tube and
out of the apertures 12.
The directing of the catheter into a particular tract will now be
described.
With the catheter tube 1 positioned in the vicinity of the tract to
be catheterized the flexible tube is advanced so that the embolus 7
is located upstream of the tract. The position of the embolus at
all times is monitored by means of X-rays. With the catheter in
this position and with the patient disposed with the tract to be
cathetered directed downwardly, the catheter or the stylet is very
slowly and gradually withdrawn, the embolus at all times moving
freely in rhythm with the pulsating bloodstream. When sufficient
withdrawal has taken place for the embolus to be disposed directly
above the tract, the embolus tends to enter the tract (as a result
of the combined effects of gravity and blood flow) and is caught in
the mouth thereof. The fact that the embolus has been so caught is
evident on the X-ray screen by virtue of the fact that the previous
pulsating movement of the embolus ceases and it is therefore
assumed that the embolus is lodged in the mouth of the tract. In
this position the stylet is pressed forward and the embolus is
freed to flow into the tract followed by the flexible tube. The
advancement of the stylet and/or the catheter is continued until
the catheter is in the required position whereupon the fluid that
is to be injected into the tract is introduced through the valve
injecting means 4. In the case that this fluid is a contrast medium
the injection of the fluid is rapidly followed by the full
representation of the region on the X-ray screen.
While in the construction just described it is desirable that when
the flexible tube has been directed to the desired position the
tube 1 is sealed by the spiralled end of the stylet, in a modified
construction this spiralled end can be dimensioned so that all
positions in the catheter tube 1, sealing thereof is effected.
It will be appreciated that while a particular technique has been
described above for using the catheter in accordance with the
invention, other techniques can equally well be used, all of which
depend, inter alia, on the flow guidance of the catheter by the
radio-opaque embolus.
After catheterization has been completed, the flexible tube and the
embolus are withdrawn into the catheter tube 2 which is detached
from the tube 1, and the latter tube is withdrawn entirely.
It will be appreciated that the novel catheter construction
described above allows for the introduction of the catheter into
regions which were hitherto accessible with the greatest
difficulty. The introduction of this catheter can furthermore be
effected very quickly with minimum traumatic risk for the patient
and with the use of standard catheter tubes. The introduction of
the novel catheter and its correct positioning does not require any
special skills as even with a relatively inexperienced operator
minimum risk of perforation exists.
* * * * *