U.S. patent number 3,561,441 [Application Number 04/659,697] was granted by the patent office on 1971-02-09 for surgical product for dressing and treating wounds, and method of manufacture.
Invention is credited to Victor J. Lombardi.
United States Patent |
3,561,441 |
Lombardi |
February 9, 1971 |
SURGICAL PRODUCT FOR DRESSING AND TREATING WOUNDS, AND METHOD OF
MANUFACTURE
Abstract
An improved surgical fabric for covering and treating wounds and
promoting healing thereof is described. The fabric includes
nonsticking loops, sheared or unsheared, on at least one face for
contacting the wound and for spacing the remainder of the fabric
away from the wound. The yarn loops may be synthetic and may
include a polyfluorinated polyolefin in filament, spun or plastic
ribbon form as a nonsticking material, or may incorporate spun
yarns of natural fibers suitably treated to impart nonstick
characteristics. The nonsticking loops may be included as part of a
knitted fabric construction, and additional, but shorter loops,
sheared or unsheared, may be provided in the same fabric for
wicking and/or absorbing liquids away from the region of the wound
which is being treated. The improved surgical fabric may be
produced on small circular knitting machines so as to produce a
tubular, seamless fabric which can be placed around a limb or other
body portion which is to be covered and treated. Stretch material
may be incorporated in the tubular fabric to help prevent the
accumulation of wound fluids and to assist in the retention of the
dressing on a preferred placement over a wound. Although the fabric
is described with reference to important surgical applications, it
will be understood that the fabric is generally useful in
applications requiring a transmittal and/or absorption of liquid
from any surface area, as for example in diaper constructions or
constructions for other articles of apparel.
Inventors: |
Lombardi; Victor J.
(Burlington, NC) |
Family
ID: |
24646431 |
Appl.
No.: |
04/659,697 |
Filed: |
August 10, 1967 |
Current U.S.
Class: |
602/44; 602/43;
66/194; 604/378; 604/384 |
Current CPC
Class: |
C08L
27/12 (20130101); D04B 1/04 (20130101); D04B
1/16 (20130101); A61L 15/24 (20130101); A61L
15/24 (20130101); A61F 13/00021 (20130101); A61F
13/00017 (20130101); A61F 2013/51492 (20130101); A61F
2013/00238 (20130101); A61F 2013/00536 (20130101); A61F
2013/00093 (20130101); A61F 2013/00246 (20130101); D10B
2509/022 (20130101); A61F 2013/00119 (20130101) |
Current International
Class: |
A61F
13/00 (20060101); A61L 15/16 (20060101); A61L
15/24 (20060101); D04B 1/00 (20060101); A61F
13/15 (20060101); A61l 015/00 () |
Field of
Search: |
;128/155--157,284
;161/89,140,164 ;66/194 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Trapp; L. W.
Claims
I claim:
1. An improved surgical product suitable for dressing and treating
wounds comprising:
a knitted fabric having loops included in at least one face
thereof, said loops being included in the knitting of the fabric,
and said loops having a nonsticking characteristic and being of a
sufficient dimension to space the remainder of the fabric away from
the wound so that there is adequate ventilation and drainage of the
wound with substantially no sticking of the fabric to the
wound.
2. The surgical product of claim 1 wherein said loops include a
synthetic yarn having a nonsticking characteristic.
3. The surgical product of claim 2 wherein said synthetic yarn
includes a copolymer of tetrafluoroethylene and hexafluoropropylene
to impart nonsticking characteristics.
4. The surgical product of claim 1 wherein said loops include a
film slit in narrow ribbon form and having a nonsticking
characterisitc.
5. The surgical product of claim 4 wherein said film slit in narrow
ribbon form includes a homopolymer of tetrafluoroethylene to impart
nonsticking characteristics.
6. The surgical product of claim 1 wherein said loops include a
yarn spun with natural fiber and treated for nonsticking
characteristics.
7. The surgical product of claim 2 wherein said synthetic yarn
includes a homopolymer of tetrafluoroethylene to impart nonsticking
characteristics.
8. The surgical product of claim 4 wherein said film slit in narrow
ribbon form includes a copolymer of tetrafluoroethylene and
hexafluoropropylene to impart nonsticking characteristics.
9. The surgical product of claim 1 wherein said loops include a
polyfluorinated polyolefin as a nonsticking material.
10. The surgical product of claim 1 and including additional loops
in said fabric which are of a smaller loop dimension than said
loops, whereby said additional loops are normally spaced out of
tight contact with a wound when the surgical product is applied
thereto.
11. The surgical product of claim 10 wherein said additional loops
have a shrinking characteristic.
12. The surgical product of claim 11 wherein said additional loops
include a polyvinyl chloride as a shrinking material.
13. The surgical product of claim 11 wherein said additional loops
include a polyolefin film slit in narrow ribbon form as a shrinking
material.
14. The surgical product of claim 1 wherein said fabric includes a
stretch component in its construction.
15. The surgical product of claim 1 wherein said product is formed
and used as a tubular knitted product having no seams.
16. An improved surgical product for dressing and treating wounds
comprising:
a knitted fabric having multilevel loops formed in at least one
face in the knitting thereof, said multilevel loops including
longer loops formed from a yarn having a nonsticking characteristic
and shorter loops formed from a yarn having a wicking or absorption
characteristic, said said longer loops being of a sufficient size
and number to space said shorter loops out of tight contact with a
wound to be covered, whereby adequate ventilation and drainage of
the wound is assured, and wherein substantially no sticking or
abrading of the wound by the surgical product takes place.
17. An improved surgical product for dressing and treating wounds
comprising:
a knitted fabric having multilevel loops formed in at least one
face in the knitting thereof, said multilevel loops including
longer loops formed from a film slit into narrow ribbons having a
nonsticking characteristic and shorter loops formed from a yarn
having a wicking or absorption characteristic, said longer loops
being of a sufficient size and number to space said shorter loops
out of tight contact with a wound to be covered, whereby adequate
ventilation and drainage of the wound is assured, and wherein
substantially no sticking or abrading of the wound by the surgical
product takes place.
18. The surgical product of claim 16 wherein said multilevel loops
are formed and extend substantially vertically of the ground
fabric.
19. The surgical product of claim 16 wherein said multilevel loops
extend substantially horizontally and are formed close to the
ground fabric.
20. The surgical product of claim 19 wherein said multilevel loops
are formed randomly in a knitted fabric.
21. The surgical product of claim 19 wherein said multilevel loops
are formed as a lay-in in a knitted fabric at selected wale and
course positions.
22. The surgical product of claim 16 wherein said multilevel loops
are formed with yarns of different size at each level.
23. The surgical product of claim 1 in combination with a separable
secondary material for absorbing wound fluids.
24. The surgical product of claim 16 wherein said longer loops
include a polyfluorinated polyolefin as a nonsticking material.
25. The surgical product of claim 16 wherein said shorter loops
include a polyvinyl chloride as a wicking material.
26. The surgical product of claim 16 wherein loops are formed on
two opposite faces of the fabric.
27. The surgical product of claim 16 wherein multilevel loops are
formed on one face of said fabric and additional loops are formed
on a second face of the fabric.
28. The surgical product of claim 27 wherein said multilevel loops
on the one face include longer loops having a nonsticking
characteristic and shorter loops having a wicking characteristic,
and said additional loops on the second face of the fabric being
formed from a yarn having an absorption characteristic, whereby
liquid matter from the wound is carried through the fabric when
said one face of the fabric is placed on the wound.
29. The surgical product of claim 16 wherein said fabric is a
knitted fabric.
30. The surgical product of claim 16 wherein said fabric and all
loops formed therein are knitted on a circular knitting machine so
as to produce a seamless, tubular product.
31. The surgical product of claim 30 wherein said knitted product
includes a stretch yarn in the fabric.
32. The surgical product of claim 30 wherein said knitted tubular
product includes a band of stretch material in said fabric to fix
the position of said tubular product around a limb or body portion
having a wound which is to be dressed and treated.
33. The surgical product of claim 32 wherein two or more bands of
stretch material are incorporated in said tubular product so as to
provide compression of said surgical product on opposite sides of a
wound being covered by the product.
34. The surgical product of claim 30 wherein said tubular knitted
product includes an area of looped knitting in the portion of the
product which is to cover a wound, and plain knitting in areas
which are not intended to cover a wound.
35. An improved surgical product for dressing and treating wounds
comprising a knitted fabric having loops formed in at least one
face in the knitting thereof, said loops being sheared to form a
pile, said sheared loops being located in at least a single level
above the knitted fabric, certain of said sheared loops formed with
a material having a nonsticking characteristic, and other of said
sheared loops formed with a material having a wicking
characteristic so that there is adequate ventilation and drainage
of the wound with substantially no sticking of the fabric to the
wound.
36. The surgical product of claim 35 wherein the said sheared loops
formed with a material having the wicking characteristic also have
a shrinking characteristic so that when they are shrunk they
contract to a level which is lower than the sheared loops having
the nonsticking characteristic.
37. The surgical product of claim 36 wherein the said loops at a
higher level are randomly sheared.
38. An improved surgical product suitable for dressing and treating
wounds comprising a knitted ground fabric incorporating a yarn
having a wicking or absorbing characteristic, and loops knitted
integrally therewith, said loops exhibiting nonsticking and wicking
characteristics.
39. The surgical product of claim 38 wherein the ground fabric
incorporates a yarn having an absorbing characteristic.
40. The surgical product of claim 38 in combination with a
secondary material for absorbing wound fluids.
41. In a method for forming an improved surgical fabric having at
least two levels of loops, with a higher level of loops having a
nonsticking characteristic and with a lower level of loops having a
wicking characteristic, the improvement comprising the steps
of:
knitting a looped fabric from at least two different yarns, and
utilizing a shrinkable yarn in the fabric as a yarn for forming
loops having a wicking characteristic, and
treating the fabric to shrink the shrinkable yarn, thereby
providing a fabric having wicking loops at a lower level than
nonsticking loops.
42. The method of claim 41 wherein said shrinkable yarn includes a
polyvinyl chloride material, and wherein said treating step
comprises a step of heating the fabric sufficiently to shrink the
shrinkable yarn.
43. The method of claim 41 and including a step of shearing all
loops of the fabric prior to treating the fabric, whereby a fabric
having at least two levels of sheared loops will be formed.
Description
BACKGROUND AND BRIEF SUMMARY OF THE INVENTION
This invention relates to fabrics of loop construction, sheared or
unsheared, for surgical applications, and more particularly, the
invention is concerned with providing an improved surgical dressing
or bandage, which includes nonsticking components for promoting
drainage, ventilation, and healing of a wound relative to the main
body of the fabric which is dressing and covering the wound.
In the treatment of wounds, certain significant factors must be
considered in order to assure quick healing of a wound without
danger of infection. These factors include provisions for proper
drainage of the wound secretions, ventilation of the wound to
prevent overheating, nonadhesion of the wound to a dressing which
is covering it, and immobilization of the wound during the healing
process.
Effective drainage hastens the drying of a wound and promotes
faster healing and resistance to infection. It is known that this
factor is especially important during the first few days of a
healing process, when the danger of infection is greatest.
Accordingly, it has been a practice to apply dressings to wounds
for assisting in the absorption and removal of secretions from the
wounds. Furthermore, clinical tests have demonstrated that
compression of a wound by a highly absorbent material helps to
prevent the accumulation of wound fluids, thereby accelerating the
healing process while minimizing exposure to infection. However,
the compression of a highly absorbent material on a wound may
result in an adhesion of wound tissue to the dressing material, and
this tends to retard the healing process because the new tissue or
scab associated with the wound may be partially or completely torn
off when such a dressing material is changed. As a result, there is
a tendency to change dressings less frequently than would normally
be desirable, and this practice can result in inadequate
ventilation and overheating of a wound, thus increasing
susceptibility to infection. It is also important that a wound be
immobilized as much as possible to insure healing without
disturbance by external pressures. Such pressures frequently arise
from shrinkage of the bandage or dressing material which is
covering the area of the wound, and this may result in pain and
irritation of the wound and a prolonging of the healing
process.
Various attempts have been made in the past to improve bandages,
dressings and other surgical fabrics or products which can be
utilized for covering and protecting a wound which is being treated
and healed. Some prior art attempts have emphasized the importance
of immobilization of a wound by maintaining shrinkable threads of a
dressing out of contact with a wound. Such an arrangement is shown
in U.S. Pat. No. 2,924,252, Feb. 9, 1960. Also, a certain amount of
"breathing" or ventilation for a wound has been attempted by adding
a foam rubber layer to a bandage or dressing, as exemplified in
patent 3,033,201, May 8, 1962. Also, it is known to include
hydrophobic and hydrophilic fibers in a woven fabric which is
intended to be used as a diaper as disclosed in 3,113,570, Dec. 10,
1963. However, the present invention is directed to a substantial
improvement in a surgical fabric which may be used for dressing
wounds and which considers all of the factors discussed above with
respect to a quick healing of a wound without danger of
infection.
The surgical product of this invention is constructed to satisfy
the requirements of drainage, nonadhesion, ventilation and
immobilization of a wound, as discussed above. These factors are
satisfied by the provision of novel loop constructions, sheared or
unsheared, for the fabrics of this invention, which may be produced
on weaving, tufting, stitch or loop bonding, flocking, and on warp
as well as weft knitting equipment. The surgical fabrics which will
be described in detail below may comprise a single-face loop
construction wherein loops appear on one side of the fabric only,
or the fabrics may be of double-face loop construction having loops
on both sides of the fabric. It is also intended that the improved
fabrics of this invention may be produced as open width or as
tubular constructions. Furthermore, it is contemplated that the
loop constructions of this invention may be sheared on an overall
or a random basis to create pile effects in the fabric. In this
regard, shearing will expose more of the filaments or fibers of the
loop yarns thereby facilitating the wicking and/or absorbing of
wound fluids and at the same time enhancing the nonsticking
characteristics of the construction. In addition, whether in
continuous loop form or in sheared form, the fabrics of this
invention may incorporate in the loop yarns, fibers, slit plastic
ribbons, or filaments of dissimilar shrink characteristics. This
will permit, in desired instances, during the process of
manufacture, the formation of loops of one level throughout the
fabric construction, and then by the appropriate application of
heat during the finishing process, the shrinkage of certain of the
loops more than others, thereby creating the different levels in
the finished fabric for the purposes herein described.
The products may be knitted on circular knitting machines of small
diameter to produce seamless, tubular loop constructions which are
especially suitable for use on leg and arm wounds. In addition, the
tubular knit constructions can incorporate stretch yarn components,
which may be in the form of compressive bands located at opposite
ends of the tubular dressing product. The spaced bands function to
apply sufficient constrictive force to help prevent the
accumulation of wound fluids, while at the same time obviating the
need for adhesive tapes or other means for holding the surgical
dressing in place.
The improved surgical product of this invention may be in the form
of a fabric, whether knitted or not knitted, having a loop
construction, sheared or unsheared, in at least one face of the
fabric. The loop and/or pile construction may be single or multiple
level, and the said multiple level may be created mechanically or
by the use of loop yarns which shrink in differential amounts in
the presence of heat. Furthermore, by the provision of a loop
and/or pile construction, air pockets are incorporated in the
structure and these assure adequate ventilation and drainage of a
wound covered by the surgical dressing of this invention. Further,
the loop or pile construction of this invention includes a
nonsticking characteristic for all loops or pile which normally
contact the wound, and such a characteristic is achieved by forming
the wound contacting loops or pile from a material which may
include a polyfluorinated polyolefin to impart nonsticking
characteristics. It has been found that such loops may in some
instances, be made with a monofilament yarn formed from a copolymer
of tetrafluorethylene and hexafluoropropylene (FEP), with a
multifilament yarn formed from a homopolymer of tetrafluorethylene
(TFE), or with yarn spun with fibers of the above polymers. In
addition, it has been found that such loops may be made with
ribbons slit to appropriate widths from films produced with resins
of the above polymers (sold under the Registered Trademark
"Teflon"). It will be understood that spun yarns of natural fibers
may be treated with resins of the polymers noted above to impart
the nonsticking characteristic.
The invention also provides for multiple level loop constructions
wherein longer loops are made with yarn or slit film in narrow
ribbon form having a nonsticking characteristic, while lower level
loops are made from a yarn which has wicking or absorbing
characteristics. When the multilevel loop construction appears on
one face only of the fabric, it is preferred that the longer loops
be made from a ployfluorinated polyolefin yarn or slit ribbon and
that the shorter loops be made from a highly absorbent yarn such as
cotton. However, if this construction includes a so-called backing
or ground yarn, then the longer loops can be made with the
polyfluorinated polyolefin yarn, the shorter loops with a yarn
exhibiting good wicking characteristics, and the ground yarn with a
highly absorbent fiber such as cotton. On the other hand, when the
dressing product is of the type having a double-face loop
construction, it is preferred that a multilevel loop construction
be provided on the wound contacting face while a single level,
highly absorbent loop construction is provided on the opposite face
of the dressing. The multilevel loop construction preferably
includes long loops which have a nonsticking characteristic and
shorter loops having a wicking characteristic for transmitting
liquid to the highly absorbent loops on the opposite face of the
dressing.
The invention further contemplates a construction in which
differential loop levels are achieved by incorporating in the
fabric loop yarns exhibiting shrinkage characteristics different
from each other. For example, if a construction of single loop
level is provided with a polyfluorinated polyolefin yarn or slit
film such as "Teflon" at certain loops, and a shrink yarn such as
polyvinyl chloride or polyvinylidene chloride (such as the
polyvinyl chloride fiber sold under the Registered Trademark
"Rhovyl" by Societe Rhovyl) at certain other loops, and a cotton
yarn for the backing or ground, and the construction subjected to
suitable heat during the finishing process, the loops in which the
polyvinyl chloride is present will contract thereby bringing their
level below that at which the "Teflon" loops remain. Consequently,
the "Teflon" loops which contact the wound will prevent sticking of
the dressing to the wound, whereas the shrink yarn such as
"Rhovyl," which also exhibits excellent wicking characteristics,
will convey the wound secretions to the absorbent backing or ground
cotton yarn. Furthermore, ribbons slit to an appropriate width from
a polyolefin film such as heatshrinkable polyethylene may be used
to provide the shrinking characteristic previously noted.
It will be appreciated that if the previously described loop fabric
is sheared on an overall basis as one of the steps of its
manufacture prior to exposing it to suitable heat, differential
shrinkage of the sheared loops will create a multiple level pile
fabric. This pile construction will expose more ends of fiber at an
upper level to provide gentler contact between the bandage and the
wound, and more ends of fiber at a lower level away from the wound
to provide increased capacity for accelerating the wicking of wound
fluids to an outer absorbent fiber. Furthermore, it will be
understood that if the so-called higher loops incorporate the
shrink yarn, such as polyvinylidene chloride, the lower loops, the
nonstick polyfluorinated polyolefin component, and the ground, the
absorbent cotton yarn, and the fabric sheared to a level slightly
above that of the polyfluorinated polyolefin loops, random sheared
effects can be developed. By subjecting such a random sheared
construction to suitable heat, the polyvinylidene chloride pile can
be shrunk to a level below that of the unsheared polyfluorinated
polyolefin loops.
The invention also provides for multiple-level loop constructions
comprising yarns, described previously, in which the loops are
positioned closer to the so-called ground fabric. This construction
may take the form of a float configuration in which longer floats
may contain the nonstick yarn, the shorter floats, the wicking
yarn, and the ground fabric, the absorbent cotton yarn. This
construction will result in a flatter, lighter weight surgical
dressing uniquely suited for the treatment of less serious
wounds.
As already mentioned, a knitted product may be formed on a small
diameter circular knitting machine to provide a tubular, seamless
dressing product having all of the desired loop constructions. The
tubular dressing product has special utility for covering limbs of
the body, and a stretch yarn component may be incorporated in such
a product to provide for a compression of the tubular dressing
around the wound area. In a preferred tubular dressing product,
loop constructions will be provided only in the area of the
dressing which is intended for covering a wound, and the remainder
of the dressing may be formed with no loops so as to decrease the
weight of the dressing product. In this preferred construction,
stretch bands may be provided at each end of the tubular dressing
so as to compress the dressing at spaced regions adjacent to the
wound area. In this manner, a wound may be easily covered and
protected, and the dressing is maintained in its required position
without the use of adhesive tape or other securing means.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a sectional elevational view of a surgical dressing
fabric of this invention wherein the fabric is provided with a
multilevel loop construction on a single face thereof;
FIG. 2 is a view similar to the view shown in FIG. 1, but showing a
surgical dressing fabric having loop constructions on opposite
faces of the fabric;
FIG. 3 schematically illustrates patterns of loop construction
which may be utilized in surgical fabrics according to this
invention;
FIG. 4 illustrates a further pattern of loop construction which may
be used in a surgical fabric;
FIG. 5 is a stitch diagram of a knitted fabric made in accordance
with this invention and having the loop construction pattern shown
in FIG. 3A;
FIG. 6 illustrates a tubular knitted fabric incorporating loop
construction and other features of this invention;
FIG. 7 is a sectional, elevation view of a surgical dressing fabric
of this invention wherein the fabric is provided with a
single-level loop construction on a single face which has been
sheared as one step in its manufacture;
FIG. 8 is a view similar to FIG. 7 illustrating the multiple levels
of pile resulting from the differential shrinkage of the sheared
loop yarns;
FIG. 9 is a perspective view illustrating a multiple level loop
construction in which the loops are positioned closer to the ground
fabric; and
FIG. 10 is a stitch diagram of a knitted fabric made in accordance
with this invention and having the loop construction pattern shown
in FIG. 9.
DETAILED DISCUSSION OF THE INVENTION
Referring to FIG. 1, a surgical fabric made in accordance with this
invention and suitable for dressing a wound is indicated generally
at 10. The fabric may be of a knitted or nonknitted construction,
but an important feature of the invention is the provision of a
loop construction on at least one face of the surgical fabric so
that the main body of the fabric is spaced away from actual contact
with a wound area 12. In the FIG. 1 embodiment, a multilevel loop
construction is shown on a single face of the fabric, that face
being the surface which normally contacts and covers a wound to be
treated. The multilevel loop construction includes relatively long
loops 14 which actually contact the wound area 12 together with
shorter loops 16 which are disposed away from a tight contact with
the wound area. The longer loops 14 function to space the main body
of the fabric away from the wound area for a sufficient distance to
provide good drainage and ventilation of the wound. As discussed
above, it is important to provide for removal of wound secretions
away from the wound area, and at the same time for ventilation of
the wound to prevent overheating and susceptibility to infection.
It is also a feature of this invention that the longer loops 14
function to prevent sticking or adhering of the surgical dressing
to the wound itself. The long loops 14 are preferably made from a
yarn or slit film in narrow ribbon form having a nonsticking
characteristic, and such a yarn or ribbon may be made wholly or
partially from a polyfluorinated polyolefin. The desired
characteristic of nonsticking is included in yarns, fibers, or
films made from polymers of tetrafluoroethylene (sold under the
registered trademark "Teflon"), or polymers of
trifluorochloroethylene (sold under the registered trademark
"Kel-F"). The feature of nonsticking is extremely important for a
rapid and safe healing of a wound, and this feature coupled with
provisions for adequate drainage and ventilation results in a
substantially improved surgical product for covering, treating and
protecting wounds. By utilizing longer nonsticking loops 14 for
actual contact with a wound area, there is provided a good
immobilization of the wound despite any minor shrinking or other
movement of the surgical dressing 10 relative to the wound. Since
the contacting loops 14 are of a nonsticking characteristic,
shrinking movements or other movements of the bandage or dressing
will not irritate or abrade the wound or any tissue which is
healing in the wound.
The shorter loops 16 of the FIG. 1 embodiment may be made of a yarn
such as cotton or rayon yarns or fibers which is highly absorbent
to liquids. The combination of a spacing layer of loops 14 with an
absorbent layer of loops 16 provides for rapid drainage and
ventilation of the wound area in a manner which promotes healing.
In an alternative arrangement, the shorter loops 16 may be made
from a yarn having good wicking characteristics, such as a yarn
including a polyvinyl chloride or nylon. In the alternative
arrangement, a ground yarn 18 may be provided in the fabric to
absorb liquid which is wicked away from the wound area by the
shorter loops 16. Of course, it is to be understood that the ground
yarn 18 may be provided in a woven or nonwoven mat or fabric
through which loops 14 and 16 are formed. On the other hand, the
entire surgical dressing 10 may be formed by knitting and the
ground yarn 18 may be included in ground loops which combine the
yarns of all of the loops. Furthermore, it will be understood that
the surgical dressing of FIG. 1 may include a wicking yarn for the
ground yarn 18. With this arrangement, a secondary covering
material 19, exhibiting highly absorbent characteristics, may
cooperate with the primary surgical dressing to absorb the wound
fluids which wick through the primary dressing. Consequently, the
primary dressing will remain relatively free from wound secretions
and the secondary covering material 19 can be readily discarded as
conditions dictate. Properly sterilized by autoclaving or
otherwise, the primary dressing can be made reuseable.
FIG. 2 represents a second embodiment wherein a loop construction
is provided on opposite faces of a surgical dressing product 10. As
discussed for FIG. 1, the wound contacting face may include a
multilevel loop construction wherein longer loops 14 and shorter
loops 16 are directed toward the wound area when the dressing is
applied. The longer loops 14 have a nonsticking characteristic
while the shorter loops 16 may have a wicking characteristic for
carrying liquid away from the wound area. With the construction
shown in FIG. 2, an increased absorption capacity can be provided
by the loop construction 20 on a face of the dressing which is away
from the wound area being covered. The loops 20 are preferably made
from a yarn having a high absorption characteristic so that wound
secretions which are wicked toward the outer surface of the
surgical dressing 10 can be absorbed and retained by the dressing.
It will be appreciated that the construction shown in FIG. 2
provides for a very substantial absorption surface, and yet, ample
ventilation and drainage is provided in the region of the wound
itself. Alternatively, the shorter loops 16 may also have a liquid
absorbing characteristic, and in that case, a dressing is provided
with a maximum absorption capacity.
As shown schematically in FIG. 3, the high and low loop
configurations which have been discussed with reference to FIGS. 1
and 2 may be of any desirable pattern. For example, FIG. 3A
illustrates a loop pattern wherein high and low loop areas and
areas having no loops at all are arranged in horizontally disposed
rows. FIG. 3B illustrates a vertically patterned configuration of
high and low loops only. FIG. 3C illustrates a configuration
wherein high and low loops are offset from one another in a more
randomized pattern than that shown in B and C. Although the
patterns of FIG. 3 are shown for only one surface of a surgical
dressing, it will be understood that loop constructions and loop
patterns may appear on a reverse side of the fabric as well. FIG. 4
illustrates a further pattern example wherein concentric bands of
high loops 14 and low loops 16 are provided on a surface of the
surgical fabric. Of course, any other pattern or configuration may
be provided to accommodate specialized dressing applications and
wound treatments.
FIG. 5 illustrates a stitch diagram of a knitted fabric which
incorporates the loop construction features of the present
invention. The stitch construction shown in FIG. 5 corresponds to
the pattern layout schematically illustrated in FIG. 3A, and the
numbered courses in FIG. 5 correspond to course numbers indicated
in FIG. 3. The fabric of FIG. 5 includes high loops 14 in course 1,
low loops 16 in course 3, and common ground loops 22. As discussed
with reference to FIGS. 1 and 2, the high loops 14 are preferably
made of a polytetrafluorethylene yarn, in filament, fiber of slit
film form so that these wound contacting loops will have a
nonsticking characteristic. The lower loops 16 may be made of an
absorbent yarn or a wicking yarn. The ground loops 22, similarly,
may be made of an absorbent or a wicking yarn for the purposes
previously described. The yarn used to form ground loops 22 is
interknitted with the high loops 14 in course 1, with the low loops
16 in course 3, and knitted alone in courses 2 and 4.
FIG. 6 illustrates a novel surgical dressing product in the form of
a seamless tubular dressing which may be knitted on a small
diameter circular knitting machine. A conventional knitting machine
may be adapted to form the high and low loop configurations of this
invention in the tubular article of FIG. 6, and the article may be
formed with loops on one or both faces of the tubular product. When
the multilevel loops are to be used on one face, such loops would
normally appear on the inner surface 24 of the seamless tubular
product illustrated. Additionally, loops may be provided on the
outer surface 26 for absorbing liquid which is carried away from
the wound area. The tubular article of FIG. 6 is especially useful
for covering wounds on legs or arms, since it is only necessary to
slide the tubular dressing over the limb which is being protected
until the area of the wound is covered. It is also a feature of the
FIG. 6 embodiment that a stretch component, or stretch yarn, may be
included in the knitted structure of the tubular dressing. By
giving the dressing a certain amount of stretch, a desirable
compression of the wound area is provided for helping to prevent
the accumulation of wound secretions. Although the stretch yarn or
stretch component of the knitted article of FIG. 6 may be included
throughout the knitted structure, it is preferred that stretch
yarns be limited to bands 28 which are formed around the entire
tubular structure and at spaced positions at opposite portions
thereof. The bands 28 may be so spaced as to lie adjacent opposite
ends of a wound which is being covered, and thus, the constrictive
forces of the tubular dressing will be limited to the areas of the
two bands 28. With this arrangement, the tubular dressing can be
applied and held in place without a requirement for adhesive tape
or other securing means.
FIG. 6 also illustrates a preferred knitted construction wherein
the loop construction is limited to the region of the tubular
article which is intended to cover the wound. This region is
indicated generally at 30 in the construction shown for FIG. 6, and
the remainder of the body 32 of the tubular dressing may comprise
plain knitting so as to decrease the fabric weight in those
portions of the bandage or dressing where additional bulk is not
required.
FIG. 7 illustrates a construction of this invention in which the
loops have been sheared to a single level, thereby exposing more of
the end fibers or filaments. In this embodiment, there is shown the
loop legs 14 which result when the nonsticking loops have been
sheared, and the loop legs 16 which result when the wicking loops
have been sheared. Through the shearing process, a more gentle
contact between the wound 12 and the nonstick yarn 14 is achieved,
and at the same time, improved wicking of wound fluids to the
absorbent ground 18 is made possible.
FIG. 8 represents a sheared fabric construction similar to that
shown in FIG. 7. However, in this embodiment, the wicking yarn 16
also has the capability for shrinkage which can be developed in the
presence of heat during finishing process. In this regard, a
polyvinylidene chloride or polyvinyl chloride yarn such as "Rhovyl"
may be used to provide the desired shrinkage and at the same time,
the wicking required. It, accordingly, will be appreciated that
differential loop or pile levels can be achieved in a construction
which is of uniform loop or pile height prior to exposure to heat.
For example, if a fabric incorporating a polyvinyl chloride fiber,
such as "Rhovyl 55" is subjected to a heat ranging from 170.degree.
F. to 212.degree. F., shrinkage of the polyvinyl chloride component
will result, and at 212.degree. F. the shrinkage will approach
approximately 55 percent. Lesser shrinkage can be provided for by
the use of other polyvinyl chloride fibers.
FIG. 9 is a further embodiment of the invention illustrating a
multiple-level loop construction comprising longer nonsticking
loops or floats 14, shorter wicking loops or floats 16, and a
ground fabric incorporating highly absorbent ground yarn 18. In
this instance, however, both the nonsticking as well as the wicking
loops are positioned closer to the ground fabric resulting in a
flatter as well as a lighter surgical dressing. A dressing of this
character can be effectively utilized for the less serious type of
wound treatment. In addition to the use of long nonsticking loops
14 in combination with the shorter wicking loops 16 to create
multiple-level loops, it will be understood that differential loop
levels can also be created by the use of a fine count or light yarn
for the wicking yarn, and a coarse count or heavier yarn for the
nonsticking yarn. The heavier nonsticking yarn will contact the
wound whereas the light wicking yarn will function to transmit the
wound fluids to the outer absorbent ground fabric. Of course, the
shorter loops 16 might include a fiber incorporating a shrinkage
characteristic, alone or in combination with a wicking
characteristic, as previously described. The use of a shorter loop
16, of FIG. 9, with a shrink characteristic will, upon the
application of suitable heat to the fabric, cause the loop 16 to
contract, thereby drawing the fabric in widthwise, and in so doing,
forcing the loops 14 outwardly to create differential levels
between the loops 16 and the loops 14.
FIG. 10 illustrates a knitted stitch diagram of the construction
shown in FIG. 9. The construction is referred to in the art as
single jersey having been produced on a knitting machine with a
single set of needles. In the diagram, the ground fabric
incorporates ground loops 23 made with a ground yarn 18, and the
longer nonsticking loops 14 and the wicking loops 16 are introduced
in the fabric as long and short lay-in loops respectively. It is to
be understood that the long nonsticking loops and the shorter
wicking loops can be positioned in any desirable configuration in
the fabric. It will be further appreciated that the concept
illustrated in FIG. 10 is equally applicable to fabrics of rib as
well as other knitted constructions. When utilized in a fabric of
rib construction, the surgical dressing may have the added
advantage of not curling at its edges.
Similarly, the use of heavy nonsticking yarns at certain warp and
filling positions of a woven fabric, and lighter wicking and/or
absorbent yarns at certain other positions in the same fabric, will
result in a flat lightweight woven construction exhibiting the
nonsticking, wicking and/or absorbing characteristics desirable in
a surgical dressing. In addition, a shrinkable fiber may be
included in a woven fabric in the manner discussed for the knitted
fabric of FIG. 9.
Having described the preferred embodiments of the present
invention, it can be appreciated that there is provided a
substantially improved surgical dressing having a novel combination
of features which promotes healing of a wound. It is contemplated
that many variations can be made in the invention, as described
above, and the surgical dressing may be made in any sizes or shapes
that may be desired. For example, the tubular construction which
was described with reference to FIG. 6 may be conceivably knitted
in relatively long lengths with multilevel loop construction
throughout the interior surface of the long tubular length. Such
long lengths could then be cut or otherwise divided up into
suitable shorter sizes for adaptation to varying sizes of wounds.
These and other variations and applications will become obvious to
those skilled in the art, and all such variations and uses are
intended to be included within the scope of the claims.
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