U.S. patent number 3,867,945 [Application Number 05/359,984] was granted by the patent office on 1975-02-25 for catheter stylets.
Invention is credited to Wendell M. Long.
United States Patent |
3,867,945 |
Long |
February 25, 1975 |
CATHETER STYLETS
Abstract
The present invention relates to a new adjunct to the insertion
of a urethral catheter. It is a catheter stiffener and former made
of a plastic rod which has the properties of being a flexible,
resilient member capable of properly stiffening a urethral catheter
or the like while also being sufficiently compliant to pre-shaping
into various and multiple curvatures to facilitate insertion into a
body cavity.
Inventors: |
Long; Wendell M. (Oklahoma
City, OK) |
Family
ID: |
23416121 |
Appl.
No.: |
05/359,984 |
Filed: |
May 14, 1973 |
Current U.S.
Class: |
604/170.02;
606/108; 604/915 |
Current CPC
Class: |
A61M
25/00 (20130101); A61M 25/0041 (20130101); A61M
25/09025 (20130101); A61M 25/10 (20130101); A61M
2025/0063 (20130101); A61M 25/0017 (20130101) |
Current International
Class: |
A61M
25/00 (20060101); A61M 25/10 (20060101); A61m
025/00 () |
Field of
Search: |
;128/341,348-351 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truluck; Dalton L.
Attorney, Agent or Firm: Laney, Dougherty, Hessin &
Fish
Claims
What is claimed is:
1. An improvement for use in combination with urethral catheters of
the type having a drainage lumen and a reduced diameter inflation
lumen disposed in parallel through the length thereof, a proximal
end for insertion in the urinary bladder, and a distal end
including an enlarged diameter drainage outlet communicating with
the drainage lumen and an inflation control outlet communicating
with said inflation lumen, the improvement consisting of a
stiffener and former device comprising:
rod means of uniform cross-sectional configuration and reduced
length relative to said drainage lumen and extending from proximal
to distal ends and having a diameter which is substantially less
than that of said drainage lumen for insertion therein throughout
the length thereof, said proximal end being formed with an optimal
curvature;
a handle portion secured to the distal end of said rod means, said
handle portion being formed with uniform cross-section slightly
larger than said drainage outlet;
whereby said rod means may be inserted throughout the entire length
of said drainage lumen with said handle means tightly received
within the drainage outlet of said urethral catheter to stiffen the
catheter while reducing its overall circumference for urethral
insertion.
2. The improvement as set forth in claim 1 which is further
characterized in that:
said rod means proximal end curvature is formed as two
substantially equal angular bends subtending an arc defining said
optimal curvature.
3. The improvement as set forth in claim 1 which is further
characterized in that:
said rod means and said handle means are formed from resilient
plastic material.
4. The improvement as set forth in claim 3 which is further
characterized in that:
said plastic material is nylon.
5. The improvement as set forth in claim 3 which is further
characterized in that:
said rod means and said handle means are unitarily formed as
uniform, round elements having pre-determined respective
diameters.
6. The improvement as set forth in claim 5 which is further
characterized in that:
said rod means has a diameter of approximately 1/16 inch and said
handle means has a diameter of approximately three-eights inch.
7. The improvement as set forth in claim 6 which is further
characterized in that:
said rod means and said handle means are unitarily formed from
nylon.
8. The improvement as set forth in claim 1 wherein:
said urethral catheter is the type known as the Foley urethral
catheter.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to surgical devices for aiding in
catheter insertion into a body cavity and, more particularly, but
not by way of limitation, it relates to an improved urethral
catheter stiffener and former, i.e., as variously termed a stylet,
mandrin or catheter guide, and the invention is particularly
adapted for use with the Foley urethral catheter.
2. Description of the Prior Art
The prior art includes various types of catheter stylets, not only
for use in Foley-type urethral catheters but other catheters as
designed for insertion in particular body cavities, i.e.
endotrachea catheters, trocar catheters, etc. Generally, the prior
forms of stylets have been formed from wire or other rigid metallic
materials. The prior art devices, especially as employed for
insertion of urethral catheters, had inherent shortcomings due to
the very fact of their necessary rigidity. The use of the
conventional wire stylets required manipulation and insertion by a
trained urologist in performance of the routine as well as the more
difficult catheterizations, as the wire guide could very easily
force the catheter to pierce the delicate wall of the urethra when
not properly avoiding obstructions.
SUMMARY OF THE INVENTION
The present invention contemplates a readily expendable catheter
stiffener formed of desirably resilient material and it is
particularly adapted for use with the Foley urethral catheter. The
stiffener and former consists of an elongated portion having the
proximal end formed with a pre-selected curvature and a distal
portion with an enlarged diameter formed for co-action with the
distal end of the Foley catheter. The proximal end of the stylet is
formed with a curvature of optimum radius for encounter with the
particular obstructions and curvatures present along the urethral
tract.
Therefore, it is an object of the present invention to provide a
catheter stylet that is semi-rigid and sufficiently stiff to guide
the catheter during insertion and to prevent collapsing of the
catheter tube.
It is still another object of the invention to provide a stiffener
and former which may be pre-formed into a variety of curves as
selected to implement insertion of the catheter device.
It is yet another object of the present invention to provide a
catheter stylet having greater resiliency and which is unlikely to
damage the fragile lumen of the urethra when the catheter is
inserted.
It is also an object of the present invention to provide a
stiffener of simple design having no moving parts which is
inexpensive to manufacture and may be disposable after a single
usage.
It is therefore an object to provide a stiffener and former
compatible with the design of the Foley urethral catheter which may
be factory inserted for sale with the Foley catheter as a unit,
thereby reducing extra handling and contamination prior to its
usage.
Finally, it is an object of the present invention to provide a
stiffener and former for use with the Foley catheter which will
enable the more routine catheterization to be carried out by nurses
or physicians assistants without danger of damage to the urethral
tract of the patient.
Other objects and advantages of the invention will be evident from
the following detailed description when read in conjunction with
the accompanying drawing which illustrates the invention.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a top plan view of the stiffener and former as
constructed in accordance with the present invention;
FIG. 2 is a side elevation of the stiffener of FIG. 1;
FIG. 3 is a side elevation of an alternative form of stiffener;
FIG. 4 is a vertical section of a Foley urethal catheter as is
well-known in the prior art;
FIG. 5 is a vertical section of the Foley catheter with stiffener
inserted; and
FIG. 6 is a section taken along lines 6--6 of FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings in greater detail, FIGS. 1 and 2 show
a catheter stiffener and former 10 as constructed in accordance
with the present invention. The stiffener and former 10 is
comprised of a rod 12 as securely joined or affixed to what may be
termed a handle 14. A proximal end portion 16 is then pre-formed
with a curvature 18 of selected radius, generally not too severe
but of sufficient curvature to allow optimum probing manipulation
during catheter insertion. A proximal tip 20 of rod 12 is rounded
off to prevent damage to the proximal end portions of the catheter
and/or the urethral wall.
Rod 12 is preferably formed from selected plastic materials having
the requisite properties as to resiliency, and prototype stiffener
and formers 10 have been successfully formed from nylon rod stock
of approximately one-sixteenth inches in diameter. The handle 14
may also be formed of the similar plastic material, and it should
be of cylindrical formation having a diameter of approximately
three-eights inches such that it fits snuggly in the distal end of
a Foley catheter, as will be further described below. Thus, a bore
22 may be formed in handle 14 to receive the end of rod 12 therein
to be secured through interference fit. While the rod 12 and handle
14 are shown as being formed in two separate pieces, it should be
understood that the stiffener and former 10 can be formed unitarily
in one piece through conventional plastic molding practices.
While the stiffener and former 10 is shown in FIG. 2 as having a
curvature 18, that which is known as the single curved or coude'
tip, some practitioners prefer, and the exigencies of certain
therapeutic applications may demand, a double curved tip 24 such as
is shown in FIG. 3. The curve 24 also subtends a relatively gentle
curvature through formation of two distinct angular bends 26 and
28.
FIG. 4 represents a standard form of Foley urethral catheter as is
now well-known in the art. The Foley catheter is the particular
subject matter of U.S. Pat. Nos. 2,428,407 and 3,152,592 and the
teachings embodied therein have enjoyed wide application and
success. Conventionally, insertion of the Foley catheter has
required either the use of a wire-form stylet with its attendant
piercing and injury problems, or the attending physician has had to
apply excessive lubrication and short stroke insertions of very
time-consuming and uncertain nature.
Briefly, the Foley catheter 30 consists of a distal portion 32 and
tube portion 34, the tube portion 34 being formed to include a
drainage lumen 36 and an inflation or control lumen 38. The Foley
catheter's may be formed as bi-luminal or tri-luminal tubes, at
least one of which, such as tube 38, is in communication with a
balloon 40 which is sealingly connected about tube portion 30
proximate the proximal end 42 of catheter 30. Dash-lines 44
illustrate in section the balloon 40 after it has been inflated to
the attitude wherein it prevents withdrawal of tube portion 34 from
the bladder. The drainage conduit 36, of larger diameter, is in
communication with the fluid drainage holes 46 as formed near the
proximal tip 42 of catheter 30. At the distal end, catheter 30 is
formed with a control tube 48 in communication with control lumen
38 and serving to provide inflation and de-inflation control. A
closure element 50 within control tube 48 serves to maintain
inflation pressure within the balloon 44 when in use. A drainage
outlet 52 in communication with drainage lumen 36 provides drainage
outlet for urine and collected fluids.
FIGS. 5 and 6 illustrate the catheter 30 with the stiffener and
former 10 inserted therein in operational position. Thus, the rod
12 is inserted along the entire length of drainage lumen 36 such
that its rounded tip end 20 is fully inserted up to proximal tip 42
of catheter 30. The handle 14 of stiffener and former 10 is
inserted within drainage outlet 52 to provide a reasonably tight
fit to maintain stiffener and former 10 securely positioned within
catheter 30 during entry manipulation. The length of rod 12 has
been established so as to extend through the length of the catheter
shaft or drainage lumen 36 such that the handle 14 receives snug
fit in the distal end thereof, i.e., drainage outlet 52. In
practice, the catheter is actually stretched slightly to cause it
to conform to the shape of the former and to thereby further
decrease the diameter of the catheter 30 itself. This constraint
also serves to prevent buckling or collapsing of the catheter
during insertion and manipulation.
OPERATION
In practice, the relatively resilient stiffener and former 10 is
inserted into the catheter 30 as shown in FIGS. 5 and 6.
Thereafter, the attending physician, attendant or nurse can then
easily manipulate the catheter 30 for probing entry into the
urethra of the requiring patient so that the proximal end 42 and
drainage holes 46 are entered sufficiently into the urinary
bladder. Thereupon, inflation control is exercised to inflate
balloon 40 thereby to retain proximal end 42 within the bladder
confines. Then, the attendant needs only to loosen the handle 14
from drainage outlet 52 to easily withdraw the rod 12 of stiffener
and former 10. The catheter 30 is then in operational placement and
the stiffener and former 10 may be discarded.
In practice it is envisioned that such catheters could be supplied
to the physician or hospital with the stiffener and former 10
already inserted therein. After one use only, the stiffener and
former would then be discarded. Such capability has the obvious
advantages of sterilization assurance, and the minimal cost of
stiffener and formers 10 should be quite acceptable for the
disposability concept.
Some properties which make a catheter and former combination most
desirable are (1) a certain degree of stiffness for ease of
insertion; (2) some angulation at the tip to allow the tip to "ride
over" obstructions; (3) highest proportion of luminal to catheter
diameter ratio; (4) flexibility and softness of the catheter once
inserted so as to not to cause undue stress and pressure on the
fragile surface of the urethra; (5) inertness of the catheters
material; (6) reduced expense; and (7) the facility of use.
Previously used wire guides did not have the optimum compromise of
qualities and were quite difficult to use safely and handily since
the wire-guided catheter could not be relied upon to "ride over"
obstructions but rather to constantly endanger piercing of the
urethral wall.
With the present shortage of qualified doctors, more and more
catheterizations are done by nurses and physicians assistants, and
generally speaking they do not have sufficient training or
qualifications to perform difficult catheterizations which require
the use of a stylet or, more important, they do not recognize the
complications which may result from the use of the conventional
stylets. Thus, the present invention converts the usual Foley
catheter into an instrument capable of performing many of the more
difficult as well as the routine catheterizations safely.
In summary, the aims and design of the catheter stiffener and
former permit the use of a soft pliable urethral catheter with a
large drainage lumen as compared to the catheter diameter. The
catheter walls can be made thinner to increase the ratio of lumen
to catheter size, thus allowing more free drainage of urine from
the bladder during operative usage. The stiffener and former will
permit easy passage of the catheter through the normal urethral
canal or when narrowed, angulated, or otherwise obstructed through
disease, such passage being made safely without buckling or
collapsing of the drainage channels. The catheter stiffener is
designed to be cheap and amenable to mass production as it can be
packaged already within the catheter and ready for the insertion
procedure.
Changes may be made in the combination, arrangement and size as
heretofore set forth in the specification and shown in the
drawings; it being understood that changes may be made in the
embodiments disclosed without departing from the spirit and scope
of the invention as defined in the following claims.
* * * * *