U.S. patent number 5,045,080 [Application Number 06/944,135] was granted by the patent office on 1991-09-03 for surgical fabric with printed x-ray marker.
This patent grant is currently assigned to Johnson & Johnson Medical, Inc.. Invention is credited to Thomas A. Denny, John Dyer, Stephen Papp, Jr..
United States Patent |
5,045,080 |
Dyer , et al. |
September 3, 1991 |
Surgical fabric with printed X-ray marker
Abstract
Woven and nonwoven fabrics for use in surgical procedures are
printed with a radiopaque polymeric composition which bonds to the
surface of the fabric. The composition is applied in a visually
distinctive pattern, or may assume the pattern of the underlying
fabric. The polymeric composition is readily recognized in an X-ray
image and provides an improved means for detecting a surgical
sponge inadvertently left in a patient. Preferred compositions are
latex or plastisols of a printable viscosity containing from 15 to
70% by weight BaSO.sub.4 having a particle size greater than about
5 microns.
Inventors: |
Dyer; John (Randolph, NJ),
Denny; Thomas A. (East Brunswick, NJ), Papp, Jr.;
Stephen (Edison, NJ) |
Assignee: |
Johnson & Johnson Medical,
Inc. (Arlington, TX)
|
Family
ID: |
25480856 |
Appl.
No.: |
06/944,135 |
Filed: |
December 22, 1986 |
Current U.S.
Class: |
604/362 |
Current CPC
Class: |
A61F
13/44 (20130101); A61L 31/18 (20130101); A61L
15/18 (20130101); A61B 90/39 (20160201) |
Current International
Class: |
A61L
15/18 (20060101); A61L 15/16 (20060101); A61L
31/14 (20060101); A61L 31/18 (20060101); A61B
19/00 (20060101); A61F 013/00 () |
Field of
Search: |
;604/362 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Rosenbaum; C. Fred
Claims
We claim:
1. In a method of preparing a surgical sponge comprising an
absorbent fabric having an X-ray detectable marker associated
therewith, the improvement comprising applying a flowable,
uniformly radiopaque polymeric composition to said fabric in a
visually distinctive pattern and securely bonding said polymeric
composition to said fabric to provide an X-ray discernable marker
having an X-ray detectable pattern corresponding to the pattern of
said polymeric composition as applied to said fabric.
2. The method of claim 1 wherein said polymeric composition is a
plastisol or latex emulsion containing a heavy metal salt,
dispersed uniformly therein.
3. The method of claim 2 wherein the heavy metal salt is BaSO.sub.4
having an average particle size greater than about 5 microns.
4. The method of claim 1 wherein the polymeric composition has a
printable viscosity.
5. The method of claim 4 wherein the polymeric composition is a PVC
plastisol containing from 15 to 70% by weight BaSO.sub.4.
6. The method of claim 4 wherein the polymeric composition is an
acrylic latex emulsion containing from about 15 to 70% by weight
BaSO.sub.4.
7. The method of claim 4 wherein the polymeric composition is
applied to the fabric by printing means.
8. The method of claim 7 wherein said printing means is gravure or
screen printing.
9. The method of claim 7 wherein said polymeric composition is
applied uniformly to the fabric and the visually distinctive
pattern conforms to the structure of the underlying fabric.
10. The method of claim 9 wherein said underlying fabric is a woven
surgical gauze or a nonwoven fabric having an open structure.
11. The method of claim 7 wherein said polymeric composition is
applied to the fabric in a visually distinctive pattern determined
by the printing means.
12. The method of claim 11 wherein said fabric is a closely woven
or knitted structure.
13. The method of claim 1 wherein said surgical sponge is a swab or
laparotomy pad.
14. A surgical sponge including an X-ray detectable marker
comprising an absorbent fabric having a uniformly radiopaque
polymeric composition bonded to the surface thereof in a visually
distinctive pattern conforming to the structure of the underlying
fabric, the pattern defined by said polymeric composition being
discernable by X-ray.
15. A sponge of claim 14 wherein said fabric comprises surgical
gauze or a nonwoven fabric having an open structure.
16. A sponge of claim 14 wherein said radiopaque polymeric
composition contains from about 60 to 85 percent by weight
BaSO.sub.4.
17. A sponge of claim 16 wherein said BaSO.sub.4 has an average
particle size greater than about 5 microns.
18. A surgical sponge including an X-ray detectable marker
comprising a substantially nonapertured fabric having a uniformly
radiopaque polymeric composition printed onto the surface of said
fabric and bonded thereto in a visually distinctive pattern, the
pattern defined by said polymeric composition being discernable by
X-ray.
19. A sponge of claim 18 wherein said fabric is a closely woven or
knitted material or a nonapertured nonwoven fabric.
20. A sponge of claim 18 wherein said radiopaque polymeric
composition contains from about 60 to 85 percent by weight
BaSO.sub.4.
21. A sponge of claim 20 wherein said BaSO.sub.4 has an average
particle size greater than about 5 microns.
Description
FIELD OF INVENTION
This invention relates to X-ray detectable fabrics and, more
particularly, to surgical swabs and sponges which include a printed
X-ray detectable marker as an integral component of the sponge
fabric.
BACKGROUND OF THE INVENTION
Various absorbent fabric materials are used in surgical procedures
for packing, wiping, and cleansing in or around the operating site.
Typical products include surgical sponges such as 4.times.4 inch
folded surgical gauze of nonwoven fabric, and woven, nonwoven and
knitted laparotomy pads. Although standard operating room
procedures require all materials brought into the operating area to
be accounted for upon completion of the procedure, an occasional
sponge may inadvertently be left in the patient. It is accordingly
common practice in the medical field to include a radiopaque marker
on all surgical sponges so that the presence or absence of a sponge
in a patient experiencing difficulty after an operation can be
determined by X-ray examination rather than by reoperating on the
patient.
A common X-ray detectable marker used in conjunction with surgical
sponges is a polymeric filament or ribbon loaded with an X-ray
opaque filler material such as barium sulfate. Suitable polymeric
materials include polyisobutylene, polyvinyl chloride and
copolymers of vinyl acetate and vinyl chloride. Such X-ray
detectable elements have been incorporated into sponge material by
a variety of techniques. In the case of gauze swabs, a filament has
been interwoven into the fabric of the gauze or fused to the
surface of the fabric and folded into the sponge construction. In
the case of laparotomy pads, an X-ray detectable ribbon has been
enclosed in a seam stitched along one end of the pad or an X-ray
detectable filament has been incorporated into the woven handle
strap of the pad or into the body of the pad fabric. In the case of
nonwoven fabric sponges the filament has been either heat fused
onto the surface of the fabric or incorporated into the fabric by
introducing the radiopaque element during the fabric manufacturing
process.
In all cases, the X-ray detectable element has been preformed as a
ribbon, yarn or monofilament and it has been essential to securely
attach the element to the sponge fabric since if the element is
separated from the fabric during use, not only is the fabric no
longer visible by X-ray, but the separated element is easily lost
in the surgical field. For manufacturing considerations it is
desirable that the X-ray detectable marker be secured to the sponge
in a continuous and reliable manner with a minimum of labor. A
final consideration is that the X-ray detectable marker be easily
identified in an X-ray image.
It is accordingly an object of the present invention to provide an
improved X-ray detectable marker on a surgical sponge. It is a
further object of this invention to provide a surgical sponge
having a distinctive and easily detected radiopaque marker. It is a
yet further object to provide a method for applying a radiopaque
marker to a fabric in a rapid, continuous and economical manner.
These and other objects of the present invention will be apparent
from the ensuing description and claims.
SUMMARY OF THE INVENTION
A surgical sponge in accordance with the present invention
comprises a fabric and a radiopaque marker bonded to said fabric in
a visually distinctive pattern. The radiopaque marker is applied to
the fabric by extruding or printing a radiopaque polymeric
suspension or melt onto the surface of the fabric in such a way
that the surface fibers of the substrate fabric are encapsulated.
Upon heat-setting curing or coalescing the radiopaque material is
securely bound to the fabric so that it becomes an integral part of
the fabric and cannot be readily removed. Emulsion polymers such as
plastisols and latexes which are soft, rubbery materials even when
heavily loaded with barium sulfate or other radiopaque salt are
well suited for use in the present invention.
The pattern of the X-ray detectable marker is determined by the
structure of the underlying fabric and the nature of the
application means. The marker may be applied to the fabric in a
continuous process at a high rate of speed by printing with a
gravure roll. Suitable compositions for the marker comprise
biocompatible polymers containing an effective amount of a
radiopaque filler such as barium sulfate and having a viscosity
suitable for printing or other application means.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view in perspective of a folded surgical sponge having
an X-ray detectable marker in accordance with the present
invention.
FIG. 2 is a print of an X-ray image of a double thickness of a
nonwoven fabric having two narrow X-ray detectable bands printed
thereon.
FIG. 3 is a photograph of a nonwoven fabric having a radiopaque
marker applied to the surface thereof.
FIG. 4 is a print of an X-ray image of the fabric of FIG. 3
illustrating the pattern of the X-ray marker.
FIG. 5 is a photograph of another nonwoven fabric having a
radiopaque marker applied to the surface thereof.
FIG. 6 is a print of an X-ray image of the fabric of FIG. 5
illustrating the pattern of the X-ray marker.
FIG. 7 is a photograph of a surgical gauze having a radiopaque
marker applied to the surface thereof and also containing a
conventional X-ray detectable monofilament.
FIG. 8 is a print of an X-ray image of the fabric of FIG. 7.
DESCRIPTION OF THE INVENTION
The present invention consists of applying a polymeric material
containing from about 15 percent up to about 70 percent by weight
of a heavy metal radiopaque salt such as barium sulfate onto the
surface of surgical sponge fabrics. The polymeric material may be
applied as a hot melt extrusion or by printing or cold extruding a
latex emulsion or a plastisol onto the surface of the fabric in a
continuous or intermittent pattern. Upon heat-setting, curing or
coalescing, the upper layer of fibers of the underlying fabric are
encapsulated by the radiopaque material so that the marker is
securely bound to the surface of the fabric and will not separate
during normal handling or use.
The radiopaque marker is applied to the fabric in a distinctive
pattern which is readily identified in an X-ray image. In the case
of those fabrics having an open structure such as woven gauze and
certain nonwoven fabrics the radiopaque material may be applied to
the fabric in such a way as to preserve the open spaces in the
fabric whereupon the fabric structure itself becomes the
distinctive pattern of the X-ray marker.
In the case of fabrics having no distinguishable pattern such as
closely knit or tightly-woven fabrics or nonapertured nonwoven
fabrics, it is preferable to apply the radiopaque material to the
surface of the fabric in a predetermined pattern which is
controlled by the configuration of the printing roll or other
application means. Latex emulsions and plastisol formulations may
be applied to the fabric by padding, gravure printing, screen
printing, or other convenient method.
Patterned nonwoven fabrics useful in the practice of the present
invention may be prepared according to conventional hydraulic
entanglement methods. In brief these methods consist of providing a
fibrous web of randomly oriented staple length fibers positioning
the web on a patterned, apertured belt, and subjecting the web to a
plurality of high pressure hydraulic jets to entangle the fibers
into a pattern conforming to that of the supporting belt. The
entangled fibers are thereupon separated from the belt and dried on
hot drums to produce a patterned nonwoven fabric. This method of
manufacturing is described in detail in U.S Pat. Nos. 3,068,547;
3,129,466; 3,485,706; 3,494,821; and 3,681,184 and is well known to
those skilled in the art.
The nonwoven fabric may comprise any suitable combination of
natural and/or synthetic textile materials including cotton, rayon,
acrylics, polyester and nylon. A particularly preferred fiber
composition is a blend of 70% rayon (1.5 denier, approximately 3 cm
staple length) and 30% polyester (1.5 denier approximately 3 cm
staple length). The staple fibers are blended and converted to a
fibrous web on conventional textile processing equipment such as a
Rando-Webber which produces a web having random fiber
orientation.
The nonwoven fabric preferably has a dry weight of from about 1.0
to 3.0 ozs per square yard (30 to 100 g/m.sup.2), with the lighter
weights limited by the processability of the fibrous web and the
heavier weights limited by the desired utility and construction of
the sponge or swab although higher weights may be preferred for
some product applications such as laparotomy pads.
The radiopaque composition is preferably dyed or pigmented blue or
other suitable color which contrasts sharply with blood. The color
permits ready identification of the X-ray detectable element in the
sponge, facilitates sponge counting in the operating room and
further helps locate the sponge when saturated with blood during
use. As a characteristic of the sponges of the present invention,
the radiopaque material may be applied primarily to one surface of
the fabric, and is consequently visually more apparent from that
side. This increased visibility may be capitalized on when folding
the sponge by placing the radiopaque material to the outside of the
sponge.
Turning now to FIG. 1 there is illustrated a surgical sponge
indicated generally by the numeral 10, which consists of folded
fabric 11 having a radiopaque marker consisting of a pair of lines
12 and 13. The radiopaque marker lines are continuous over the
length of the folded sponge and applied to the fabric during
manufacture by, for example, printing a radiopaque plastisol
directly onto the surface of the fabric. While lines 2 and 13
appear generally as two continuous lines of uniform width and depth
closer inspection reveals that the lines conform to the open
pattern of the fabric and have a variable thickness on the surface
of the fabric. The pattern of the radiopaque material on the fabric
of the sponge results in the formation of a distinctive X-ray image
of the radiopaque marker. FIG. 2 is a print of the X-ray image of a
double thickness of a fabric having two narrow X-ray detectable
bands printed thereon. While the X-ray pattern is created entirely
by the pattern of the underlying fabric the fabric pattern itself
is not apparent from the X-ray image due to the narrow width of the
radiopaque lines.
FIG. 3 is a photograph of an open patterned nonwoven fabric which
is characterized by a series of small, widely-spaced fiber masses
interconnected by radial threads in what is commonly referred to as
a "rosebud" pattern. A radiopaque material applied uniformly to the
fabric over a width of from about 1 to 2 cm, appearing as dark
bands in FIG. 3 encompasses a sufficient area of fabric to make the
actual pattern of the fabric visible in the X-ray image as
illustrated in FIG. 4. Where such a wide band of radiopaque
material is applied to the fabric, it will usually be sufficient to
apply the material in a discontinuous line so that one or two bands
of material appear in each sponge. For example, if the length of
the fabric comprising each folded sponge is 0.5 m it would be
sufficient to apply the radiopaque material in bands of 2 cm wide
by 10 cm long at a frequency of four bands per meter of fabric,
thus assuring that each sponge would include two radiopaque
markers, at least one of which would be a continuous 10 cm
length.
FIGS. 5 is a photograph of another nonwoven fabric having a
radiopaque marker applied to the surface thereof. The X-ray image
of the fabric as illustrated in FIG. 6 clearly shows the pattern of
the fabric to be different than that of FIG. 4.
FIG. 7 illustrates a conventional 20.times.8 woven surgical gauze
printed with a band of radiopaque plastisol material which appears
as the dark bands in the photograph of FIG. 7. The radiopaque
material uniformly coats each yarn of the gauze within the area of
the coating and the pattern of the gauze is readily identified in
an X-ray image of the fabric as illustrated in FIG. 8. FIGS. 7 and
8 also include a conventional monofilament marker which is clearly
visible as the wavy line in the X-ray image of FIG. 8, and less
evident in the photograph of the fabric of FIG. 7. It should also
be noted that while the photograph and the X-ray are of the same
fabric, the displayed areas are not precisely the same.
As illustrated in FIGS. 1-8, the radiopaque material may be applied
to an open mesh fabric over an area sufficient to reveal the actual
pattern of the underlying fabric in an X-ray image or over an area
which is too narrow to disclose the repeating pattern of the
fabric, but nevertheless displays a distinctive pattern of its own
in an X-ray image as a result of the underlying fabric pattern.
In the case of closely knit or woven fabric the radiopaque material
is applied in a predetermined pattern controlled by the application
means. For example, a plastisol may be applied to the fabric by
screen printing or by gravure system in a continuous line or in
discontinuous bands and in any desirable pattern. An infinite
variety of patterns is, of course, possible and may be utilized in
the practice of the present invention. One desirable pattern would
be in the name or initials of the supplier of the surgical product
and perhaps the order number of the product, which would not only
provide X-ray detectability but also indicate the source of the
product to the surgeon during the operating procedure. Since the
surgical sponges are usually wadded up during use, it is unlikely
that this information would be fully legible in an actual X-ray
image but even a single letter of the alphabet would be distinctive
and easily recognized as a foreign object in an X-ray following a
surgical procedure.
The method of the present invention is further illustrated in the
following examples where all parts and percentages are by weight
unless otherwise indicated.
EXAMPLE 1
A plastisol printing composition is prepared from polyvinyl
chloride resin according to the following formulation:
______________________________________ 100 parts Geon 125-A PVC
resin 100 parts Dioctyl phthalate plasticizer 328 parts BaSO.sub.4
5 parts blue pigment ______________________________________
Geon.TM. 125-A PVC resin is a low molecular weight, low viscosity
polyvinylchloride powder available from B. F. Goodrich Avon Lake,
Ohio. The BaSO.sub.4 is suitably No. 1 Barytes.TM. HP available
from Pfizer, Inc., Easton, Penn. The blue pigment is suitably
Ultramarine Blue available from Sun Chemical Co., Cincinnati, Ohio.
The PVC resin is sifted with stirring into the dioctyl phthalate
plasticizer containing the blue dye, followed by addition of the
BaSO.sub.4. The resulting composition contains 61.5% BaSO.sub.4 and
has a viscosity of about 20,000 cps which is suitable for printing.
Desirable viscosities for printing are generally in the range of
5,000 to 20,000 cps although higher or lower viscosities may be
utilized in some applications.
EXAMPLE 2
An emulsion latex printing composition is prepared according to the
following formulation:
______________________________________ 25 parts water 10 parts blue
pigment 2 parts antifoam 4 parts rheology modifier 3 parts ammonia
(28%) 200 parts Rhoplex K-3 (48%) 501 parts BaSO.sub.4
______________________________________
The latex printing composition is prepared by first combining the
water, ammonia, antifoam, rheology modifier, pigment and
Rhoplex.TM. K-3, then slowly adding the BaSO.sub.4 with stirring to
obtain a mix with 67% BaSO.sub.4 solids. The ammonia functions to
increase the pH to about 8, the antifoam may be Colloids 999
available from Colloids, Inc., Newark, N.J., and the rheology
modifier may be a poly (ethylene oxide) such as poly-ox.TM.
available from Union Carbide, Danbury, Conn. Rhoplex K-3, is a 46%
aqueous acrylic emulsion available from Rohm & Haas,
Philadelphia, Penn. After application to the fabric and removal of
volatiles, the BaSO.sub.4 content in the resulting polymeric
composition is approximately 80 percent.
The radiopaque polymeric composition with BaSo.sub.4 is naturally
white, but may be pigmented blue or other color for enhanced
visibility or left uncolored except for some indication of its
presence such as a thin blue line printed onto the marker after
curing. A wide, unpigmented band of radiopaque material with a
narrow blue line or the logo of the manufacturer printed thereon,
may be more aesthetically pleasing to the surgeon and still provide
all the advantages of a wide, x-ray detectable marker as described
herein.
The plastisol or latex printing composition is applied to the
surgical fabric using conventional printing equipment and
techniques as, for example, by gravure rolls. The printed fabric is
passed through a heating station to polymerize the resin and remove
volatile components. The resulting polymeric deposit is securely
adhered to the underlying fabric and typically comprises from about
60-90% BaSO.sub.4 solids in the resin binder. We have found that at
least 10% resin binder is desirable to assure the integrity of the
polymeric mass and its adhesion to the fabric.
The BaSO.sub.4 used in the printing formulations of the present
invention preferably has an average particle size of at least 5
microns and most preferably 10 microns or greater, in order to
obtain printing compositions having the desired flow
characteristics when containing up to about 70% BaSO.sub.4 solids.
We have found that when the average particle size is substantially
less than 5 microns, as for example 2 microns, formulations
containing such high levels of Ba SO.sub.4 solids are essentially
dry mixes not suitable for application to fabric by conventional
printing means. In the case of the No. 1 Barytes HP used in the
preceding examples, the average particle size is about 10 microns
with 75 percent of the particles being 5 microns or greater.
We have also found that the X-ray detectability of a cured latex or
plastisol containing from 60 to 70 percent barium sulfate compares
favorably with that of a conventional monofilament marker which
usually contains about 60 percent barium sulfate. Moreover, the
X-ray visibility of the radiopaque material is greater, in the case
of the present invention since if the X-ray is taken in plan view
the pattern of the marker stands out while if the X-ray is taken in
side view, the effective thickness of the marker is increased and
the brightness of the marker in the X-ray image is enhanced.
The fabric may be printed on one or both sides with the radiopaque
material and superimposed printing on both sides has the advantage
of presenting thinner layers with greater surface area to speed
drying or curing of the radiopaque material. Wide lengths of fabric
may be printed with parallel bands of radiopaque material spaced to
conform to the desired final width of the sponge so that the fabric
may be slit within the bands. The radiopaque material thereby
performs the dual function of stabilizing the cut edges of the
fabric against loose yarns or linting, while at the same time
imparting X-ray detectability to the fabric.
These and other variations of the present invention which is
directed broadly to printing polymeric compositions onto fabrics
for use as surgical sponges will be apparent to those skilled in
the art. The fabrics and polymeric compositions as described herein
are for the purposes of illustration only and not limiting of the
present invention.
* * * * *