U.S. patent application number 16/757343 was filed with the patent office on 2020-12-03 for manifolding apparatus or dressing exhibiting low tissue ingrowth and negative-pressure treatment method.
The applicant listed for this patent is KCI Licensing, Inc.. Invention is credited to Diwi L. ALLEN, James COURAGE, Kristine M. KIESWETTER, Christopher Brian LOCKE, Justin Alexander LONG, Benjamin Andrew PRATT, Larry Tab RANDOLPH, Timothy Mark ROBINSON.
Application Number | 20200375805 16/757343 |
Document ID | / |
Family ID | 1000005046399 |
Filed Date | 2020-12-03 |
![](/patent/app/20200375805/US20200375805A1-20201203-C00001.png)
![](/patent/app/20200375805/US20200375805A1-20201203-D00000.png)
![](/patent/app/20200375805/US20200375805A1-20201203-D00001.png)
![](/patent/app/20200375805/US20200375805A1-20201203-D00002.png)
![](/patent/app/20200375805/US20200375805A1-20201203-D00003.png)
![](/patent/app/20200375805/US20200375805A1-20201203-D00004.png)
![](/patent/app/20200375805/US20200375805A1-20201203-D00005.png)
![](/patent/app/20200375805/US20200375805A1-20201203-D00006.png)
United States Patent
Application |
20200375805 |
Kind Code |
A1 |
ROBINSON; Timothy Mark ; et
al. |
December 3, 2020 |
Manifolding Apparatus Or Dressing Exhibiting Low Tissue Ingrowth
And Negative-Pressure Treatment Method
Abstract
An apparatus for filling a wound can include an array of at
least four truncated ellipsoids interconnected to define at least
one fluid path through, for example perpendicular to, the array.
The longest principal axis of each ellipsoid may be perpendicular
to the array. Each truncated ellipsoid may be a spheroid and/or may
include an approximately elliptical contact surface at each contact
surface between two interconnected ellipsoids. Each fluid pathway
may have four continuously-curved concave sides and may have a
parallelogram-shaped cross-section with continuously-curved concave
edges. A dressing may include the apparatus, a dressing layer
coupled to the apparatus, a backing layer disposed over a surface
of the dressing layer opposite the apparatus, and an attachment
device disposed on at least a margin of the backing layer. Methods
of treating various tissue sites using the apparatus or dressing
with negative-pressure therapy are also disclosed.
Inventors: |
ROBINSON; Timothy Mark;
(Shillingstone, GB) ; LOCKE; Christopher Brian;
(Bournemouth, GB) ; PRATT; Benjamin Andrew;
(Poole, GB) ; RANDOLPH; Larry Tab; (San Antonio,
TX) ; LONG; Justin Alexander; (Lago Vista, TX)
; COURAGE; James; (San Antonio, TX) ; ALLEN; Diwi
L.; (San Antonio, TX) ; KIESWETTER; Kristine M.;
(San Antonio, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KCI Licensing, Inc. |
San Antonio |
TX |
US |
|
|
Family ID: |
1000005046399 |
Appl. No.: |
16/757343 |
Filed: |
October 22, 2018 |
PCT Filed: |
October 22, 2018 |
PCT NO: |
PCT/US2018/056831 |
371 Date: |
April 17, 2020 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62577570 |
Oct 26, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 1/0084 20130101;
A61F 13/00068 20130101; A61M 2210/1017 20130101; A61F 13/00021
20130101; A61F 13/0216 20130101; A61F 13/148 20130101; A61L 27/18
20130101; A61L 27/34 20130101; A61F 2013/00157 20130101; A61M
1/0088 20130101; A61L 27/54 20130101; A61M 2210/1021 20130101; A61F
13/0206 20130101; A61L 27/16 20130101; A61F 2013/00357
20130101 |
International
Class: |
A61F 13/14 20060101
A61F013/14; A61L 27/18 20060101 A61L027/18; A61L 27/34 20060101
A61L027/34; A61L 27/54 20060101 A61L027/54; A61M 1/00 20060101
A61M001/00; A61F 13/02 20060101 A61F013/02; A61F 13/00 20060101
A61F013/00; A61L 27/16 20060101 A61L027/16 |
Claims
1. An apparatus for filling a wound, the apparatus comprising: an
array of at least four truncated ellipsoids interconnected to
define at least one fluid path through the array; wherein the
interconnected ellipsoids are comprised of a polyolefin, a
polyester, a polyamide, a polystyrene, a polydiolefin, a
polyacrylonitrile, a polysiloxane, or a copolymer or combination
thereof; and wherein each of the interconnected ellipsoids has a
surface hardness from about 0 Shore A to about 25 Shore A.
2. The apparatus of claim 1, further comprising a coating disposed
on each of the ellipsoids that yields a surface hardness of at
least 55 Shore A.
3. The apparatus of claim 2, wherein the coating is comprised of a
cellulosic material, a polyester, a polyamide, a polycarbonate, a
perhalogenated polyolefin, an aramid, a polybenzimidazole, a
polysulfone, or a copolymer, combination, or cross-linked gel
thereof.
4. The apparatus of any one of claims 1-3, wherein each of the
truncated ellipsoids has a principal axis oriented substantially
perpendicular to the array.
5. The apparatus of any one of claims 1-3, wherein each of the
truncated ellipsoids is a truncated spheroid having a principal
axis oriented substantially perpendicular to the array.
6. The apparatus of any one of claims 4-5, wherein the
interconnected ellipsoids are truncated only at each surface where
the ellipsoids are interconnected.
7. An apparatus for filling a wound, the apparatus comprising: an
array of interconnected polymeric ovules having a truncated
ellipsoidal shape, wherein: each set of four interconnected ovules
defines a fluid pathway extending perpendicularly through the
array; each truncated ellipsoidal shape comprises an approximately
elliptical contact surface at each contact surface between two
interconnected ovules; and each interconnected polymeric ovule has
its longest principal axis oriented substantially perpendicular to
the array.
8. The apparatus of claim 7, wherein the array comprises: at least
three columns comprising two edge columns and at least one central
column; and at least three rows comprising two edge rows and at
least one central row, and wherein each set of four interconnected
ovules is arranged in two of the at least three rows and two of the
at least three columns.
9. The apparatus of claim 7 or claim 8, wherein the array comprises
four corner ovules, at least four edge ovules, at least one central
ovule, and at least four fluid pathways interstitially
therebetween, each central ovule having a truncated ellipsoidal
shape with four elliptical contact surfaces, each edge ovule having
a truncated ellipsoidal shape with three elliptical contact
surfaces, and each corner ovule having a truncated ellipsoidal
shape with two elliptical contact surfaces.
10. The apparatus of any one of claims 7-9, wherein the
interconnected ovules are comprised of a polyolefin, a polyester, a
polyamide, a polystyrene, a polydiolefin, a polyacrylonitrile, a
polysiloxane, or a copolymer or combination thereof.
11. The apparatus of any of claims 7-10, wherein each
interconnected ovule has its two principal axes other than the
longest principal axis, respectively, oriented at approximately a
45.degree. angle to a row direction of the array and at
approximately a 45.degree. angle to a column direction of the
array.
12. The apparatus of any of claims 7-11, wherein each of the
interconnected ovules are truncated only at one end of the longest
principal axis and at each surface where the ovules are
interconnected.
13. The apparatus of any one of claims 1-12, wherein the array of
interconnected ellipsoids or interconnected ovules has an upper
surface and a lower surface, and wherein the upper surface or the
lower surface or both has a hardness from about 0 Shore A to about
25 Shore A.
14. The apparatus of claim 13, wherein the upper surface or the
lower surface or both has a coating disposed thereon that exhibits
a hardness of at least 55 Shore A.
15. The apparatus of claim 14, wherein the coating is comprised of
a cellulosic material, a polyester, a polyamide, a polycarbonate, a
perhalogenated polyolefin, an aramid, a polybenzimidazole, a
polysulfone, or a copolymer, combination, or cross-linked gel
thereof.
16. The apparatus of any of claims 1-15, wherein at least a portion
of the interconnected ellipsoids or at least a portion of the
interconnected ovules comprise one or more grooves on an outer
surface of each ellipsoid or of each ovule that extend at least
partially in a direction of its longest principal axis.
17. The apparatus of claim 16, wherein each groove has an average
depth no more than 30% of a diameter of each interconnected ovule
or of each interconnected ellipsoid along a principal axis
direction other than the longest principal axis.
18. The apparatus of any of claims 1-17, wherein a longest
principal axis of each interconnected ellipsoid or each
interconnected ovule is from about 3 mm to about 6 mm.
19. The apparatus of claim 18, wherein each principal axis other
than the longest principal axis of each interconnected ellipsoid or
each interconnected ovule is from about 2 mm to about 4 mm.
20. The apparatus of any of claims 1-19, wherein each fluid pathway
has a minimum width dimension from about 500 microns to about 1500
microns.
21. The apparatus of any of claims 1-20, wherein the apparatus is
translucent.
22. The apparatus of any of claims 1-21, further comprising a wound
healing agent in or on the array, the wound healing agent
comprising a non-steroidal anti-inflammatory drug, a steroid, an
anti-inflammatory cytokine, an anaesthetic, an antiseptic, an
antimicrobial agent, a growth factor, a peptide, a microRNA, an
antioxidant, or a combination thereof.
23. The apparatus of claim 22, wherein the antimicrobial agent
comprises silver, a silver salt, a tetracycline, a beta-lactam, a
macrolide, an aminoglycoside, a fluoroquinolone, a cellulose ethyl
sulfonate, or a combination thereof.
24. An apparatus for filling a wound, the apparatus comprising: a
layer having a plurality of fluid pathways through the layer from a
first surface to a second surface, wherein: an array of connected
polymeric protrusions extends through the layer connecting the
first and second surfaces; each set of four connected polymeric
protrusions from each of the first and second surfaces defines one
fluid pathway extending perpendicularly through the array; and each
fluid pathway has four continuously-curved concave sides and has a
parallelogram-shaped cross-section with continuously-curved concave
edges.
25. A dressing for treating a tissue site, the dressing comprising:
an apparatus according to any of claims 1-24; a dressing layer
coupled to the apparatus; a backing layer disposed over a surface
of the dressing layer opposite from the apparatus; and an
attachment device disposed on at least a margin of the backing
layer.
26. The dressing of claim 25, wherein the attachment device is
configured to form a seal with a tissue site, and wherein the
dressing layer is coupled to the apparatus on a surface opposite
the protrusions, or on a surface formed by truncation of the ovules
or of the ellipsoids on one end of a principal axis oriented
substantially perpendicular to the array.
27. The dressing of claim 25 or claim 26, wherein the dressing
layer comprises an absorbent layer containing from about 45% to
about 90% carboxymethyl cellulose fibers and from about 10% to
about 55% reinforcing fibers.
28. The dressing of any of claims 25-27, wherein the dressing layer
comprises a manifolding layer configured to allow both fluid
removal and fluid instillation therethrough.
29. A system for treating a tissue site with negative pressure, the
system comprising: an apparatus according to any of claims 1-24 or
a dressing according to any of claims 25-28; and a
negative-pressure source fluidly coupled to the dressing and
configured to enable fluid removal through the dressing.
30. The system of claim 29, further comprising: a negative-pressure
conduit; and a negative-pressure connector subsystem for fluidly
coupling the negative-pressure source to the apparatus or the
dressing for fluid removal.
31. The system of claim 30, further comprising a container fluidly
coupled to the negative-pressure source and to the apparatus or to
the dressing and adapted to collect fluid.
32. A method for treating a compartmented wound site, the method
comprising: deploying within a compartmented wound site the
apparatus of any of claims 1-24, the dressing of any of claims
25-28, or at least a portion of the system for treating a tissue
site according to any of claims 29-31; deploying a
negative-pressure connector subsystem; deploying a sealing member
to form a fluid seal over the open cavity; fluidly coupling the
negative-pressure connector subsystem to a negative-pressure
source; and activating the negative-pressure source.
33. The method of claim 32, wherein the compartmented wound site
comprises a peritoneal or abdominal cavity.
34. A method for treating a surface wound site, the method
comprising: deploying over the surface wound site the apparatus of
any of claims 1-24, the dressing of any of claims 25-28, or at
least a portion of the system for treating a tissue site according
to any of claims 29-31; deploying a negative-pressure connector
subsystem; deploying a sealing member to form a fluid seal over the
surface wound site; fluidly coupling the negative-pressure
connector subsystem to a negative-pressure source; and activating
the negative-pressure source.
35. The method of claim 34, wherein the surface wound site
comprises a burn, a graft, an overhang wound, a contusion, or a
post-operative wound.
36. A method for treating a tunnel wound site, the method
comprising: deploying within the tunnel wound site the apparatus of
any of claims 1-24, the dressing of any of claims 25-28, or at
least a portion of the system for treating a tissue site according
to any of claims 29-31, the dressing substrate comprising a
cylinder or tube; deploying a negative-pressure connector
subsystem; deploying a sealing member to form a fluid seal over the
tunnel wound; fluidly coupling the negative-pressure connector
subsystem to a negative-pressure source; and activating the
negative-pressure source.
37. The method of claim 36, wherein the tunnel wound site comprises
a puncture or a fistula.
38. A method of reducing edema for a tissue site, the method
comprising positioning an apparatus of any of claims 1-24, a
dressing of any of claims 25-28, or at least a portion of a system
for treating a tissue site according to any of claims 29-31 over
the tissue site.
39. The systems, apparatuses, dressings, compositions, and methods
substantially as described herein.
Description
RELATED APPLICATIONS
[0001] This present invention claims the benefit, under 35 USC
119(e), of the filing of U.S. Provisional Patent Application Ser.
No. 62/577,570, entitled "Manifolding Apparatus or Dressing
Exhibiting Low Tissue Ingrowth and Negative-Pressure Treatment
Method", filed Oct. 26, 2017, and is incorporated herein by
reference in its entirety.
TECHNICAL FIELD
[0002] The invention set forth in the appended claims relates
generally to tissue treatment systems optionally with negative
pressure and/or instillation and more particularly, but without
limitation, to compartmented site treatment systems that may
exhibit relatively low levels of tissue ingrowth.
BACKGROUND
[0003] A wide variety of materials and devices, generally
characterized as "dressings" or "wound dressings," are generally
known in the art for use in treating an injury or other disruption
of tissue. Such wounds or tissue sites may be the result of trauma,
surgery, or disease, and may affect skin or other tissues. In
general, dressings may control bleeding, absorb wound exudate, ease
pain, assist in debriding the wound, protect tissue site from
infection, or otherwise promote healing and protect the tissue site
from further damage.
[0004] Although the clinical benefits and advantages of dressings
may be widely accepted, improvements to dressings may benefit
healthcare providers and patients.
[0005] Clinical studies and practice have also shown that reducing
pressure in proximity to a tissue site can augment and accelerate
growth of new tissue at the tissue site. The applications of this
phenomenon are numerous, but it has proven particularly
advantageous for treating wounds. Regardless of the etiology of a
wound, whether trauma, surgery, or another cause, proper care of
the wound is important to the outcome. Treatment of wounds or other
tissue with reduced pressure may be commonly referred to as
"negative-pressure therapy," but is also known by other names,
including "negative-pressure wound therapy," "reduced-pressure
therapy," "vacuum therapy," "vacuum-assisted closure," and "topical
negative-pressure," for example. Negative-pressure therapy may
provide a number of benefits, including migration of epithelial and
subcutaneous tissues, improved blood and interstitial fluid flow,
and micro-deformation of tissue at a wound site. Together, these
benefits can increase development of granulation tissue and reduce
healing times.
[0006] There is also widespread acceptance that cleansing a tissue
site can be highly beneficial for new tissue growth. For example, a
wound can be washed out with a stream of liquid solution, or a
cavity can be washed out using a liquid solution for therapeutic
purposes. These practices are commonly referred to as "irrigation"
and "lavage" respectively. "Instillation" is another practice that
generally refers to a process of slowly introducing fluid to a
tissue site and leaving the fluid for a prescribed period of time
before removing the fluid. For example, instillation of topical
treatment solutions over a tissue site can be combined with
negative-pressure therapy to further promote tissue healing by
loosening soluble contaminants at a tissue site and removing
infectious material. As a result, soluble bacterial burden can be
decreased, contaminants removed, and the tissue site cleansed.
[0007] While the clinical benefits of negative-pressure therapy
and/or instillation therapy are widely known, improvements to
therapy systems, components such as dressings, and processes may
benefit healthcare providers and patients.
BRIEF SUMMARY
[0008] New and useful compositions of tissue site filler layers,
dressing layers, and dressings including such tissue site filler or
dressing layers, methods for manufacturing same, systems including
same, apparatuses including same, and methods for treating a tissue
site, for example in a negative-pressure therapy environment, are
set forth in the following summary and description, as well as in
the appended claims. Illustrative embodiments are also provided to
enable a person skilled in the art to make and use the claimed
subject matter.
[0009] For example, in some embodiments, an apparatus for filling a
wound can include an array of at least four truncated ellipsoids
interconnected to define at least one fluid path through the array.
In some embodiments, the interconnected ellipsoids may be comprised
of a polyolefin, a polyester, a polyamide, a polystyrene, a
polydiolefin, a polyacrylonitrile, a polysiloxane, or a copolymer
or combination thereof. In some embodiments, each of the
interconnected ellipsoids may have a surface hardness from about 0
Shore A to about 25 Shore A.
[0010] In some example embodiments, an apparatus for filling a
wound can include an array of interconnected polymeric ovules
having a truncated ellipsoidal shape. In some embodiments, each set
of four interconnected ovules in the array may define a fluid
pathway extending perpendicularly through the array, and each
truncated ellipsoidal shape may comprise an approximately
elliptical contact surface at each contact surface between two
interconnected ovules. In some embodiments, each interconnected
polymeric ovule may have its longest principal axis oriented
substantially perpendicular to the array.
[0011] In some example embodiments, an apparatus for filling a
wound can include a layer having a plurality of fluid pathways
through the layer from a first surface to a second surface. In some
embodiments, an array of connected polymeric protrusions may extend
through the layer connecting the first and second surfaces. In some
embodiments, each set of four connected polymeric protrusions from
each of the first and second surfaces of the array may define one
fluid pathway extending perpendicularly through the array. In some
embodiments, each fluid pathway may have four continuously-curved
concave sides and may have a parallelogram-shaped cross-section
with continuously-curved concave edges.
[0012] In some example embodiments, a dressing for treating a
tissue site may include an apparatus for filling a wound, a
dressing layer coupled to the apparatus, a backing layer disposed
over a surface of the dressing layer opposite from the apparatus,
and an attachment device disposed on at least a margin of the
backing layer. In some embodiments, the dressing layer may include
or be a manifolding layer configured to allow both fluid removal
and fluid instillation therethrough. In some embodiments, the
dressing layer and the apparatus may be coupled together and the
apparatus may be configured to allow fluid removal. In some
embodiments, the attachment device may be configured to form a seal
with a tissue site. In some embodiments, the dressing layer may be
coupled to the apparatus on a surface opposite the protrusions, or
on a surface formed by truncation of the ovules or of the
ellipsoids on one end of a principal axis oriented substantially
perpendicular to the array.
[0013] In some example embodiments, a system for treating a tissue
site with negative pressure may include: an apparatus or a dressing
for treating a tissue site, as described above or herein; and a
negative-pressure source fluidly coupled to the dressing and
configured to enable fluid removal through the dressing. In some
embodiments the system may further include: a negative-pressure
conduit; and a negative-pressure connector subsystem for fluidly
coupling the negative-pressure source to the apparatus or to the
dressing for fluid removal.
[0014] In some embodiments, a method for treating a compartmented
tissue site, such as an overhang wound or a peritoneal or abdominal
cavity, may include: deploying within the compartmented tissue site
an apparatus, a dressing, or at least a portion of a system for
treating a tissue site; and deploying a sealing member to form a
fluid seal over an open cavity. In some embodiments, the method may
additionally include deploying a negative-pressure connector
subsystem; fluidly coupling the negative-pressure connector
subsystem to a negative-pressure source; and activating the
negative-pressure source.
[0015] In some embodiments, a method for treating a surface tissue
site, such as a burn, a graft, or a post-operative wound, may
include: deploying over the surface tissue site an apparatus, a
dressing, or at least a portion of a system for treating a tissue
site; and deploying a sealing member to form a fluid seal over the
surface tissue site. In some embodiments, the method may
additionally include deploying a negative-pressure connector
subsystem; fluidly coupling the negative-pressure connector
subsystem to a negative-pressure source; and activating the
negative-pressure source.
[0016] In some embodiments, a method for treating a tunnel wound
site, such as a puncture or a fistula, may include: deploying
within the tunnel wound site an apparatus, a dressing, or at least
a portion of a system for treating a tissue site; and deploying a
sealing member to form a fluid seal over the tunnel wound site. In
some tunnel wound site embodiments, the substrate of the dressing
or system may comprise a cylinder or tube. In some embodiments, the
method may additionally include deploying a negative-pressure
connector subsystem; fluidly coupling the negative-pressure
connector subsystem to a negative-pressure source; and activating
the negative-pressure source.
[0017] In some embodiments, a method of reducing edema and/or
increasing interstitial fluid flow for a tissue site may include
positioning an apparatus, a dressing, or at least a portion of a
system for treating a tissue site over the tissue site.
[0018] Objectives, advantages, and a preferred mode of making and
using the claimed subject matter may be understood best by
reference to the accompanying drawings in conjunction with the
following detailed description of illustrative embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIGS. 1A-1C are perspective views of a wound filler sheet
useful for treating a tissue site. FIG. 1A is a top view; FIG. 1B
is a side view; and FIG. 1C is a perspective view. FIGS. 1D-1F are
expanded views of insets D, E, and F, from FIGS. 1A, 1B, and 1C,
respectively.
[0020] FIG. 2 is a schematic diagram, with a portion in
cross-section, of an illustrative device for treating a tissue
site.
[0021] FIG. 3 is a functional block diagram of an example
embodiment of a therapy system that can deliver negative pressure
as well as a treatment fluid to a tissue site and can manage fluids
in accordance with this specification.
[0022] FIG. 4 is a schematic diagram, with a portion in
cross-section, of an illustrative device containing a dressing with
an integral wound filler sheet for treating an abdominal cavity
that may be associated with some embodiments of the therapy system
of FIG. 3.
[0023] FIG. 5 is a schematic diagram, with a portion in
cross-section, of an illustrative device containing a dressing with
an integral wound filler sheet for treating an abdominal cavity
that may be associated with some embodiments of the therapy system
of FIG. 3.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0024] The following description of example embodiments provides
information that enables a person skilled in the art to make and
use the subject matter set forth in the appended claims, but may
omit certain details already well-known in the art. The following
detailed description is, therefore, to be taken as illustrative and
not limiting.
[0025] The example embodiments may also be described herein with
reference to spatial relationships between various elements or to
the spatial orientation of various elements depicted in the
attached drawings. In general, such relationships or orientation
assume a frame of reference consistent with or relative to a
patient in a position to receive treatment. However, as should be
recognized by those skilled in the art, this frame of reference is
merely a descriptive expedient rather than a strict
prescription.
[0026] Disclosed herein are embodiments of a wound filler, a
dressing layer containing a such a wound filler, embodiments of
composite dressings including such a dressing layer, and
embodiments of therapy systems including same. Also disclosed
herein are embodiments of related methods, such as methods of
making and methods of using the disclosed wound fillers, dressing
layers, composite dressings, and therapy systems. For example, FIG.
1 illustrates an embodiment of a dressing 100. Generally, and as
will be disclosed herein, the dressing 100 may be configured to
provide therapy to a tissue site in accordance with the disclosure
of this specification.
[0027] The term "tissue site" in this context broadly refers to a
wound, defect, or other treatment target located on or within
tissue, including but not limited to, bone tissue, adipose tissue,
muscle tissue, neural tissue, dermal tissue, vascular tissue,
connective tissue, cartilage, tendons, or ligaments. A wound may
include chronic, acute, traumatic, subacute, and dehisced wounds,
partial-thickness burns, ulcers (such as diabetic, pressure, or
venous insufficiency ulcers), flaps, and grafts, for example.
Compartmented tissue may include a wound, defect, or other
treatment target in a body cavity, such as an abdominal cavity, for
example. The term "tissue site" may also refer to areas of any
tissue that are not necessarily wounded or defective, for example
with respect to pressure ulcer prevention, but are instead areas in
which it may be desirable to add or promote the growth of
additional tissue. For example, negative pressure may be applied to
a tissue site to grow additional tissue that may be harvested and
transplanted.
[0028] In some embodiments, treatment of a tissue site can include
a wound filler layer configured to interface with the tissue site.
For example, in the embodiment of FIGS. 1A-1F, the wound filler 10
an array of interconnected ovules having a truncated ellipsoidal
shape. With respect to wound fillers, such as wound filler 10, and
dressing layers made of wound filler material, the terms "ovules"
and "ellipsoids" are used interchangeably herein, often
adjectivally modified by "truncated," to refer to individual shaped
portions interconnected in array form.
[0029] FIG. 1A shows a top view of wound filler 10; FIG. 1B shows a
side view of wound filler 10; and FIG. 1C shows a perspective view
of wound filler 10. The array of interconnected ovules may exhibit
corner ovules 12, edge ovules 14, and optionally but preferably at
least one central ovule 16. Though the views of FIGS. 1A-1C show an
array containing 50 rows and 50 columns, it should be understood
that the array may be of any reasonable size and may comprise any
number of rows and any number of columns sufficient to assist in
treating a tissue site. FIG. 1A contains circle D; FIG. 1B contains
circle E; and FIG. 1C contains circle F. These circles encompass
inset areas that are magnified in FIGS. 1D, 1E, and 1F,
respectively. Corner ovules 12, edge ovules 14, and central ovules
16 are also shown in these figures.
[0030] FIGS. 1D and 1E show dimensions of one embodiment of the
array of ovules having a truncated ellipsoidal shape, which in this
embodiment constitutes a truncated spheroidal shape. Ellipsoids
generally have three orthogonal principal axes; spheroids generally
are ellipsoids but with two of the three principal axes being
approximately equal in length. In these figures, and consistent
with the embodiment shown in FIGS. 1A-1C, a principal axis of the
ovules or ellipsoids can be oriented substantially perpendicular to
the plane of the array. Also as shown in the figures, the other two
principal axes can be oriented substantially within the plane of
the array. In some embodiments, such as shown in the figures, that
substantially perpendicular axis may be the longest principal axis.
In some embodiments, such as shown in the figures, the two
principal axes other than the longest principal axis may be
oriented at approximately a 45.degree. angle to a row direction of
the array and at approximately a 45.degree. angle to a column
direction of the array, respectively.
[0031] In some embodiments, the array may comprise at least four
interconnected ovules having truncated ellipsoidal shape that
together define at least one fluid pathway 18 through the array.
For example, as shown in FIG. 1D, an array of two rows and two
columns of interconnected ovules can define a single fluid pathway
18 extending approximately perpendicularly through the plane of the
array. In some embodiments, the array may include four corner
ovules 12, at least four edge ovules 14, at least one central ovule
16, and at least four fluid pathways 18 interstitially
therebetween, for example, each defined by a set of four
interconnected ovules. In some embodiments, such as shown in the
figures, the array may include at least three columns and at least
three rows. In these embodiments, the at least three columns may
include two edge columns and at least one central column, and the
at least three rows may include two edge rows and at least one
central row.
[0032] In some embodiments, the wound filler 10 may include a layer
having a plurality of fluid pathways therethrough from a first or
top surface to a second or bottom surface. In some embodiments, the
wound filler 10 may also include an array of interconnected
protrusions extending through the layer connecting the top and
bottom surfaces, for example with each set of four interconnected
protrusions from each of the top and bottom surfaces defining one
fluid pathway extending perpendicularly through the array. In some
embodiments, each fluid pathway may have four continuously-curved
concave sides. Additionally or alternatively, in some embodiments,
each fluid pathway may have a parallelogram-shaped cross-section
with continuously-curved concave edges.
[0033] FIGS. 1D and 1E also show top view and side view,
respectively of the truncations of the ellipsoidal (spheroidal)
ovules. Each truncation is shown as an approximately flat surface
where two ovules interconnect. In some embodiments, each central
ovule may be interconnected at four contact surfaces or bond zones,
each edge ovule may be interconnected at three contact surfaces or
bond zones, and each corner ovule may be interconnected at two
contact surfaces or bond zones. In some embodiments, such as
embodiments in which the ovules in the array are spheroids each
having its longest principal axis substantially perpendicular to
the plane of the array, each contact surface or bond zone may be
approximately elliptical in shape.
[0034] In some embodiments, the interconnected ovules may be
polymeric, such as comprised of a polyolefin, a polyester, a
polyamide, a polystyrene, a polydiolefin, a polyacrylonitrile, a
polysiloxane, or a copolymer or combination thereof. In certain
embodiments, the interconnected ovules may be non-adherent to a
tissue site. In some embodiments, each of the interconnected ovules
has a surface hardness from about 0 Shore A to about 25 Shore A. In
some embodiments, the upper surface, the lower surface, or both, of
the array of interconnected ovules may exhibit a hardness from
about 0 Shore A to about 25 Shore A. In some embodiments not shown
in the figures, the upper surface, the lower surface, or both, of
the array of interconnected ovules may include a coating disposed
thereon that exhibits a hardness of at least 55 Shore A. In
embodiments when a coating is present, the coating may be comprised
of a cellulosic material, a polyester, a polyamide, a
polycarbonate, a perhalogenated polyolefin, an aramid, a
polybenzimidazole, a polysulfone, or a copolymer, combination, or
cross-linked gel thereof.
[0035] In some embodiments not shown in the figures, at least a
portion of the interconnected ovules may include one or more
grooves on an outer surface of each ovule that extend at least
partially in a direction of its longest principal axis. In
embodiments where one or more grooves are present, each groove may
have an average depth no more than 30% of a diameter of each
interconnected ovule along a principal axis direction other than
the longest principal axis. Additionally or alternatively, at least
a portion of the interconnected ovules may have an external
texture, whether in relief or counter-relief, which may be
systematic or random, such as texture patterns commercially
available from Standex Int'l. Ltd. of London, England.
[0036] It can be desirable, in some embodiments, for portions of
the ellipsoidal surfaces of the interconnected ovules forming the
upper surface of the array, the lower surface of the array, or
both, to protrude above/below portions defining the fluid pathways
through the array. Without being bound by theory, it is believed
that one or more of the sizes of, the shapes of, and the component
materials making up the interconnected ovules and defining the
fluid pathways therebetween may be tailored to allow negative
pressure to be communicated across the array, such as through the
fluid pathways without complete collapse under applied negative
pressure.
[0037] In some embodiments, such as shown in FIGS. 1D-1F, the
longest principal axis of each interconnected ovule may be from
about 3 mm to about 6 mm. Additionally or alternatively, each
principal axis other than the longest principal axis of each
interconnected ovule may be from about 2 mm to about 4 mm. In some
embodiments, each fluid pathway 18 has a minimum width dimension
from about 500 microns to about 1500 microns. In some embodiments,
the wound filler 10 may be at least partially, or completely,
translucent.
[0038] In the embodiment shown in FIGS. 1A-1F, the wound filler 10
includes only a single layer array of interconnected ovules.
However, it should be understood that the wound filler 10 can
alternatively include two or more layers of arrays of
interconnected ovules, and two or more of those layer arrays may
interconnect with each other across layers, for example via
additional truncations in the ovules. Nevertheless, any
interconnection between layers of ovules should maintain the fluid
pathways 18 existing through each array or layer, so that a
plurality of fluid pathways are retained through the entire wound
filler 10.
[0039] In some embodiments containing only a single layer array,
such as shown in FIGS. 1A-1F, the interconnected ellipsoidal
(spheroidal) ovules are truncated only at each surface where the
ellipsoids (spheroids) are interconnected. In some embodiments not
shown in FIGS. 1A-1F, each interconnected ovule is truncated only
at each surface where the ovules are interconnected and at one end
of the longest principal axis of the ovule. For example, when
tissue site therapy includes use of a wound filler 10 having a top
and a bottom surface, and when only one of those surfaces is
oriented to contact a tissue site, then the other of those surfaces
may constitute the surface at which the end of the longest
principal axis is truncated. In some embodiments, the truncation at
the one end of the longest principal axis of each ovule can occur
at approximately 50% of the length of the longest principal axis.
In other embodiments, the truncation at the one end of the longest
principal axis of each ovule can occur at between 60% and 90% of
the distance from the other end of the longest principal axis. In
most embodiments in which each ovule is truncated at one end of the
longest principal axis, the truncation may occur approximately
perpendicular to the longest principal axis, and thus approximately
parallel to the plane of the array.
[0040] The wound filler may be made using any viable technique,
such as compression or injection molding using one or more pre-made
forms. If more than one pre-made form is used, the forms can be
combined thereafter, such as by melt-joining or an equivalent
technique, to form a single as-synthesized wound filler. However,
continuous or semi-continuous manufacture may be employed as an
alternative to molding, for example by using a rotary die that can
vary its orifice appropriately to allow for extrusion of the
complex surfaces of the wound filler materials.
[0041] In some embodiments, the wound filler 10 may optionally
comprise one or more additional materials. Such optional components
may include, for example, active materials such as preservatives,
stabilizing agents, plasticizers, matrix strengthening materials,
dyestuffs, and combinations thereof. Such optional components may
additionally or alternatively include passive materials, for
example in situations when ex vivo detection may be important, such
as a sufficient amount of magnetic, metal, or ceramic material to
allow ready ex vivo detection, such as via an x-ray or MRI
apparatus. Additionally or alternatively, the wound filler 10 may
comprise one or more additional active materials, for example,
antimicrobial agents that may be effective to aid in tissue
healing. Non-limiting examples of such active materials may include
non-steroidal anti-inflammatory drugs such as acetaminophen,
steroids, antimicrobial agents such as penicillins or
streptomycins, antiseptics such as chlorhexidine, growth factors
such as fibroblast growth factor or platelet derived growth factor,
peptides, microRNA, antioxidants, and other well-known therapeutic
agents, alone or in combination. If present, such active materials
may typically be included at any effective level that show
therapeutic efficacy, while preferably not being at such a high
level as to significantly counteract any critical or desired
physical, chemical, or biological property of the wound filler.
Depending upon the therapeutic goal(s), the active material(s) may
be loaded at a level of from about 10 wppm to about 10 wt % of the
layer(s) in which it(they) is(are) present, for example, from about
50 wppm to about 5 wt % or from about 100 wppm to about 1 wt %.
[0042] In some embodiments, the wound filler 10 can have
manifolding properties and can be configured to allow fluid removal
from a tissue site, fluid instillation to a tissue site, or both,
for example by virtue of the plurality of fluid pathways 18
extending through the wound filler 10.
[0043] In some embodiments, the wound filler 10 may be configured
to be sized by a user to fit a tissue site, for example an overhang
wound or compartmented tissue such as a peritoneal or an abdominal
cavity. If sizing the wound filler 10 is necessary, excess portions
of the wound filler 10 may be removed, for example by cutting or
tearing, to attain a wound filler 10 of an appropriate size for the
respective tissue site or intended use. In some embodiments, the
wound filler 10 may be designed to contain various locations
enabling ease of cutting or tearing, such as designated weak
points, which may have a smaller cross-array thickness but which
would preferably still provide physical connectivity of the array
under most if not all operational conditions, when sizing is not
necessary.
[0044] In some embodiments, a wound filler, such as wound filler
10, can be a separate apparatus used in conjunction with a dressing
or other therapy device for providing treatment to a tissue site.
In some embodiments, a dressing or other therapy device may include
an integral wound filler layer, for example with a use of providing
treatment to a tissue site. In preferred embodiments, a wound
filler, such as wound filler 10, may function to encourage healing,
as indicated by tissue granulation, at a tissue site while
simultaneously inhibiting or minimizing ingrowth of tissue into and
around the wound filler, thereby allowing removal of the wound
filler from the tissue site with little or no pain to a
patient.
[0045] FIG. 2 shows a dressing 100 including a dressing layer 110.
The dressing layer 110 may generally be configured to be positioned
on, over, in, adjacent to, or in contact with (collectively,
"near") the tissue site.
[0046] In various embodiments, the dressing layer 110 may be
configured so as to be near a portion of a tissue site,
substantially all of a tissue site, or a tissue site in its
entirety. If a tissue site is a wound, for example, the dressing
layer 110 may partially or completely fill the wound, or may be
placed over or near the wound. In various embodiments, the dressing
layer 110 may take many forms, and may have many sizes, shapes, or
thicknesses depending on a variety of factors, such as the type of
treatment being implemented or the nature and size of a tissue
site. For example, the size and shape of the dressing layer 110 may
be adapted to the contours of deep and irregular shaped tissue
sites, may be configured so as to be adaptable to a given shape or
contour, or both. Moreover, in some embodiments, any or all of the
surfaces of the dressing layer 110 may comprise projections,
protrusions, or an uneven, course, or jagged profile that can, for
example, induce strains and stresses on a tissue site, which may be
effective to promote some granulation at the tissue site.
[0047] In some embodiments, the dressing layer 110 may be in
substantially sheet form. For example, the dressing layer 110 may
comprise a generally planar structure having two opposite-facing
planar surfaces and a depth or thickness orthogonal to the planar
surfaces. More particularly, for example, the dressing layer 110
may comprise a first or bottom surface opposite a second or top
surface. The bottom surface may be adapted to contact a tissue
site, having a surface area sufficient to contact an appropriate
portion, if not all, of the tissue site. For example, a surface
area from about 1 cm.sup.2 to about 4000 cm.sup.2 may be suitable
for many applications. In various embodiments, the top surface and
the bottom surface may have any suitable shape, examples of which
include, but are not limited to, triangles, squares, rhombuses,
rhomboids, diamonds, rectangles, trapezoids, ellipses, ellipsoids,
circles, semi-circles, pie-wedges, ovals, and various polygons
having four, five, six, seven, eight, or more sides. These shapes
may additionally or alternatively be adaptations of such common
shapes. In some embodiments, shapes with typically rounded edges
may be altered to be flatter, such as a rounded hexagonal/octagonal
shape made by flattening the rounded edges of a circle.
Additionally or alternatively, shapes with typically rounded edges
may be altered to be sharper, such as a tear-drop shape made by
sharpening a rounded end of an ellipse or ellipsoid, or such as an
eye shape made by sharpening two rounded, opposing ends of an
ellipse or ellipsoid. Further additionally or alternatively, shapes
with typically pointed edges may be altered to be more rounded,
such as for a blunt-ended triangle. Still further additionally or
alternatively, shapes with typically flat edges may be altered to
be more rounded, such as by converting the flat sides of any
regular polygon to a sinusoidal edge to form a doily shape with an
undulating, curvy edge. The shape and area of the bottom surface
may be customized to the location and type of tissue site onto
which the dressing 100 is to be applied.
[0048] There can be various embodiments of the composition of the
dressing layer. In some embodiments, the dressing layer 110 may be
a single layer; in other embodiments, the dressing layer 110 may
represent a multi-layer composite structure. For example, the
dressing layer 110 may comprise at least two adjacent layers.
[0049] In some examples, two layers of a multi-layer composite may
be coupled to each other using any appropriate technique. For
example, a lamination process can be used to couple layers
together, particularly where neither of the layers to be coupled
are fibrous. In some embodiments, an adherent layer containing an
adhesive can be used to directly or indirectly couple layers
together.
[0050] In some multi-layer embodiments, such as shown in FIG. 2,
the dressing layer 110 can include an assembly comprising a
manifolding layer 148 and a filler layer 160 made from an array of
interconnected ovules 162 with a plurality of fluid pathways
extending through the array. In some embodiments, filler layer 160
may be similar to wound filler 10 but coupled to manifolding layer
148, and therefore integral to the dressing 100 as part of dressing
layer 110. Despite the presence of fluid pathways through the
filler layer 160, when coupled, the filler layer 160 may be
described as covering the manifolding layer 148, even though fluid
is typically meant to be communicated through both the manifolding
layer 148 and the filler layer 160. Similarly, any one of the
multiple layers of the assembly may include relatively small gaps,
for example from fenestrations or perforations, that do not
strictly provide coverage of the entire surface area of any other
of the multiple layers of the assembly to which they are directly
coupled, and yet the one layer is described herein as covering the
other layer. Thus, as used herein, the term "cover" and its
grammatical variations, should be understood generally to mean
substantially cover and should not require every square micron of a
macroscopic surface to have intervening material blocking access
thereto. In some embodiments, a first or bottom surface of the
manifolding layer 148 can be coupled to a second or top surface of
the filler layer 160 by an optionally intervening adherent layer
(not shown in FIG. 2), which would be considered an additional
layer in the assembly of dressing layer 110. When present, the
optional adherent layer can individually be configured to allow
fluid flow therethrough, thereby fluidly connecting the filler
layer 160 and the manifolding layer 148. For example, the optional
adherent layer can comprise perforations or fenestrations in order
to achieve such a fluid-permissive configuration, while
simultaneously maintaining its function of adhering the two layers
together.
[0051] In various embodiments, the manifolding layer 148, or more
generally the assembly comprised within the dressing layer 110, may
individually and collectively be configured to allow fluid removal.
In such embodiments, the manifolding layer 148 in particular may
comprise fluid pathways interconnected so as to improve
distribution or collection of fluids. For example, in some
embodiments, the manifolding layer 148 may be a porous material
having a plurality of interconnected cells or pores. Examples of
suitable materials may include open-cell foam, including
reticulated foam, or porous tissue collections. In some
embodiments, the manifolding layer may comprise or be a
polyurethane foam, a polyurethane film, a melt-blow polyurethane, a
thermoplastic polyurethane (such as Daltex.RTM. Stretch from Don
& Low Ltd.), or a combination thereof. Other suitable material
may include gauze or felted mat, which generally include pores,
edges, or walls adapted to form interconnected fluid pathways. For
example, in some embodiments, the manifolding layer 148 may
comprise, consist essentially of, or be open-cell foam having pore
sizes in a range of 400-600 microns. In one non-limiting example,
the manifolding layer may be reticulated polyurethane foam.
[0052] In various embodiments, the filler layer 160 may include an
array of interconnected ovules 162 with a plurality of fluid
pathways extending through the array. In these embodiments, the
interconnected ovules 162 may be truncated ellipsoids or spheroids,
with truncations being at connection surfaces or bond zones between
ellipsoids or spheroids. In some embodiments, each ellipsoidal or
spheroidal ovule 162 can have a longest primary axis oriented
substantially perpendicular to the plane of the filler layer 160
and, in some circumstances, may have an additional truncation at
one end of its longest primary axis. In those embodiments in which
the additional truncations are present, as shown in FIG. 2, the
truncations can form the top surface, proximate to the bottom
surface of the manifolding layer 148 to which the array, and thus
the filler layer 160, is coupled. One, some, or all of the
features, characteristics, and composition of the wound filler 10
shown in FIGS. 1A-1F or described herein can be a feature,
characteristic, or composition of the filler layer 160, shown in
FIG. 2 in side view, in a similar viewpoint to the wound filler 10
in FIGS. 1B and 1E.
[0053] Because of its disposition as the first or bottom surface of
the dressing layer 110, the filler layer 160 may comprise or be
made from materials suitable for exposure to or implantation within
tissue sites. Such materials themselves may cause some levels of
granulation or immune response when in contact with tissue sites
but are typically not designed to result in extreme edema,
widespread immune response, reduction of interstitial fluid flow,
or any bodily response that significantly negatively interferes
with tissue site treatment. In some embodiments, the filler layer
material may be non-adherent. Non-limiting examples of filler layer
materials may include a polyolefin, a polyester, a polyamide, a
polystyrene, a polydiolefin, a polyacrylonitrile, a polysiloxane,
or a copolymer or combination thereof. In some embodiments, the
filler layer 160 may comprise a polysiloxane.
[0054] In some embodiments, the periodicity of interconnected
ovules 162 in the filler layer 160 along the plane of the array may
be from about 0.25 mm to about 6 mm, for example from about 0.5 mm
to about 1.5 mm, from about 0.25 mm to about 5 mm, from about 0.5
mm to about 5 mm, from about 1 mm to about 5 mm, from about 3 mm to
about 6 mm, from about 2 mm to about 4 mm. As used herein, the term
"periodicity," with respect to interconnected structures such as
ovules, should be understood to mean a repeat unit distance. This
repeat unit distance may be measured in any reasonable way. For
example, for the interconnected ovules 162 in filler layer 160, the
periodicity along the plane of the array can be expressed as a
distance between protrusion peak centers, whether along columns or
along rows, or as a distance between the through-thickness fluid
pathway centers, which may each represent approximately the same
periodicity for spheroidal ovules with longest principal axes
substantially perpendicular to the plane of the array. An
alternative measure of periodicity along the plane of the array may
be the length of a principal axis other than the longest principal
axis of each interconnected ovule, which would represent a planar
array width, whether a column width or a row width, of the
truncated ellipsoids or spheroids.
[0055] Without being bound by theory, it is believed that a
tissue-contacting surface made of non-adherent materials and/or
having non-porous protrusions and fluid pathways therethrough,
particularly within a certain size range, may reduce, inhibit, or
eliminate unintended tissue growth into a dressing. When
granulation extends significantly into the dressing layer of a
dressing, removal of that dressing to end tissue treatment or at an
end of a phase of tissue treatment may cause pain or discomfort to
a patient and may include removing some portion of the granulation
along with the dressing. By having protrusions and fluid pathways
with dimensions falling within particular size ranges, for example,
granulation around the protrusions and among the fluid pathways may
typically be more easily disengaged during removal of the dressing,
and the likelihood of troublesome granulation ingrowth can be
reduced, inhibited, or eliminated, along with the accompanying pain
and discomfort to the patient.
[0056] In some embodiments, the assembly containing the manifolding
layer 148 and filler layer 160 may be configured to be sized by a
user to fit the tissue site; indeed, the dressing layer 110 or the
entire dressing 100 itself may be sized to fit the tissue site and
disposed at or within a tissue site, for example an overhang wound.
In some embodiments, excess portions of the dressing layer 110 or
the dressing 100 may be removed, for example by cutting or tearing,
to attain a dressing layer 110 or a dressing 100 of an appropriate
size.
[0057] In some embodiments, at least a portion of the
interconnected ovules 162 in the array of the filler layer 160 may
comprise grooves along a length of each ovule 162. If present, the
portion of the ovules 162 exhibiting grooves may have an average
groove width at half-depth from about 0.4 mm to about 1.5 mm, for
example from about 0.5 mm to about 1.0 mm. Additionally or
alternatively, if present, the grooves may have a depth up to 30%
of the ovule width along the plane of the array of the filler layer
160. The grooves, if present, may take any suitable shape in fiber
cross-section, examples of which include, but are not limited to,
triangles, squares, rhombuses, rhomboids, diamonds, rectangles,
trapezoids, ellipses, ellipsoids, circles, semi-circles,
pie-wedges, ovals, and various polygons having four, five, six,
seven, eight, or more sides. These shapes may additionally or
alternatively be truncations or adaptations of such common shapes.
In some embodiments, shapes with typically rounded edges may be
altered to be flatter, such as a rounded hexagonal/octagonal shape
made by flattening the rounded edges of a circle. Additionally or
alternatively, shapes with typically rounded edges may be altered
to be sharper, such as a tear-drop shape made by sharpening a
rounded end of an ellipse or ellipsoid, or such as an eye shape
made by sharpening two rounded, opposing ends of an ellipse or
ellipsoid. Further additionally or alternatively, shapes with
typically pointed edges may be altered to be more rounded, such as
for a blunt-ended triangle. Still further additionally or
alternatively, shapes with typically flat edges may be altered to
be more rounded, such as by converting the flat sides of any
regular polygon to a sinusoidal edge to form a doily shape with an
undulating, curvy edge. Without being bound by theory, it is
believed that the presence of ovule grooves may assist in inducing
macrostrain and microstrain at the tissue site, for example in
tandem with application of negative pressure.
[0058] In some embodiments, the manifolding layer 148 may be
perforated or fenestrated, particularly in cases where it is
desirable to combine application of the dressing 100 containing the
manifolding layer 148 with negative-pressure treatment to a tissue
site. Additionally or alternatively, the manifolding layer 148 may
comprise or be made from an open-cell foam, a mesh, paper,
non-woven fibers, woven fibers, or the like. In such embodiments,
the perforations, the fenestrations, the porosity, or the
interconnectedness of cells in the manifolding layer material may
allow the manifolding layer 148 to enable, facilitate, or allow
fluid removal from a tissue site, fluid instillation to a tissue
site, or both therethrough. In some embodiments, the manifolding
layer can comprise or be made from any of a variety of different
materials. For example, the manifolding layer 148 may contain a
thermoplastic elastomer, a polyurethane, poly(vinyl chloride), a
polyester, a polyether, a polystyrene copolymer, or a combination
thereof.
[0059] In some embodiments, the manifolding layer 148 may comprise
an absorbent material adapted to absorb fluid and adapted to
reduce, inhibit, or eliminate in vivo granulation, particularly for
manifolding layers that are foams or are porous. In one
non-limiting example, the absorbent material may comprise a
cross-linked hydrogel, such as a hydrophilic poly(vinyl alcohol).
The absorbent material may be present within or on one or more
surfaces of the manifolding layer.
[0060] In some embodiments, such as shown in FIG. 2, the dressing
layer 110 may include an absorbent layer 145. For example, the
dressing layer 110 may comprise a composite island having one or
more absorbent layers. The absorbent layer 145 may comprise a
non-woven material of predominantly non-woven fibers, in some
embodiments. For example, in various embodiments, the absorbent
layer 145 may comprise from about 45 parts to about 100 parts by
weight of cellulosic (for example, cellulose ether) fibers and
optionally up to about 55 parts by weight of reinforcing fibers. In
particular embodiments, the absorbent layer may comprise from about
45 parts to about 95 parts by weight, from about 45 parts to about
90 parts by weight, from about 50 parts to about 90 parts by
weight, from about 60 parts to about 90 parts by weight, from about
65 parts to about 85 parts by weight, or from about 70 parts to
about 90 parts by weight of cellulosic fibers and about 55 parts to
about 10 parts by weight, from about 50 parts to about 10 parts by
weight, from about 45 parts to about 10 parts by weight, from about
40 parts to about 10 parts by weight, from about 35 parts to about
15 parts by weight, from about 30 parts to about 10 parts by
weight, from about 30 parts to about 15 parts by weight, or from
about 25 parts to about 10 parts by weight of reinforcing fibers.
In some optional embodiments, biodegradable components may
additionally be present in an absorbent layer, for example in
amounts from about 1 part to about 20 parts by weight, such as from
about 1 part to about 15 parts by weight or from about 1 part to
about 10 parts by weight. In some embodiments, absorbent fibers may
be comprised of about 80 parts to about 100 parts by weight of
cellulosic, for example cellulose ether such as carboxymethyl
cellulose, fibers and optionally up to about 20 parts of
reinforcing fibers, biodegradable components, or both.
[0061] In some embodiments, absorbent material may be absent in or
removed from a zone within the absorption layer 145. Such
embodiments offer an additional or alternative mechanism enabling
at least partial fluid absorptive expansion within the absorption
layer 145, which can enable additional degrees of freedom for fluid
absorption while creating no or little additional pressure on the
tissue site. For example, by creating a central zone in the
absorbent layer 145 of the dressing layer 110 that is absent of
material, the other portions of the absorbent layer 145 can have
extra volume to expand and can optionally experience increased
fluid flow within the dressing layer 110, thus rendering the
absorbent layer 145 more efficient.
[0062] In some embodiments, the absorbent layer 145 may be
perforated to increase fluid flow, to reduce time to equilibrium
absorption, or both. Such embodiments offer another additional or
alternative mechanism enabling additional degrees of freedom for
fluid absorption while creating no or little additional pressure on
the tissue site.
[0063] If cellulosic fibers are present in the absorbent layer 145,
the cellulosic fibers may be composed of at least one of
carboxymethyl cellulose (CMC), carboxylethyl cellulose,
hydroxyethyl cellulose, hydroxypropyl cellulose,
hydroxypropylmethyl cellulose, and cellulose ethyl sulphonate (CES)
(particularly carboxymethyl cellulose), for example. In some
embodiments, the cellulosic component may be at least partially in
a salt form, for example, comprising a physiologically acceptable
cation such as sodium. CMC is commercially available from a variety
of sources, such as under the tradenames WALOCEL.TM. (sold by The
Dow Chemical Company) and CEKOL.RTM. (sold by CP Kelco). If
reinforcing fibers are present in the absorbent layer 145, for
example, the reinforcing fibers may be composed of at least one of
non-gelling cellulose, a polyurethane gel, an amide polymer such as
Nylon 6,6, an olefin polymer such as HDPE, an ester polymer such as
PET, and a modified acrylamide polymer. If biodegradable components
are present in the absorbent layer 145, for example, the
biodegradable components may be composed of, but not limited to, an
alginic acid, an alginate salt, chitosan, chitin, a guar gum, a
locust bean gum, a xanthan gum, a karaya gum, gelatin, pectin, a
starch derivative such as a dextran, a glycosaminoglycan, a
galactomannan, a chondroitin salt, heparin, a heparin salt,
collagen, oxidized regenerated cellulose (ORC), hyaluronic acid, a
hyaluronate salt, or a combination thereof. For such listed salt
components, the salt components may include any reasonable
counterions, such as sodium, calcium, ammonium, or the like, or
combinations thereof. The biodegradable component(s) can be, for
example, in the form of a film or foam, such as open-cell foam,
including reticulated foam, or combinations thereof. If in foam
form, the average pore size may vary according to needs of a
prescribed therapy, for example, from about 400 microns to about
600 microns. Other physico-chemical properties of biodegradable
components, such as tensile strength, may be chosen or manipulated,
for example, to be suitable to needs of a prescribed treatment.
[0064] In some multi-layer embodiments, if an absorbent layer 145
is present, a surface of the absorbent layer 145 not coupled to the
manifolding layer 148 can be oriented away from the bottom surface
of the dressing layer 110. In some embodiments, it may be
advantageous for an absorbent layer to be separated from a tissue
site, for example, such that the surface of the absorbent layer not
coupled to the manifolding layer can be oriented away from the
bottom or tissue-contacting surface of the dressing layer 110.
[0065] In some embodiments, particularly if biodegradable
components are included, the dressing layer 110 may be
characterized as having some biodegradable character or as
exhibiting biodegradability. "Biodegradable" and "biodegradability"
may individually or collectively refer to a characteristic of a
material to disintegrate, degrade, or dissolve upon exposure to
physiological fluids or processes, for example, if the dressing
layer 110 is applied to a tissue site. For example, in some
embodiments, the dressing layer 110 or a material from which the
dressing layer 110 is formed may form a gel if contacted with an
aqueous medium, such as water, saline, blood, or exudate. Such
biodegradability may be exhibited as a result of chemical process
or condition, a physical process or condition, or some combination
thereof. For example, the biodegradable characteristics of the
dressing layer 110 may substantially reduce or eliminate the need
to remove the dressing layer 110 from a tissue site to which it is
applied. In some embodiments, at least about 90% by weight of the
biodegradable component (particularly at least about 95% by weight,
at least about 99% by weight, or about 100% by weight) may be
disintegrated, degraded, or dissolved within a time period of from
about 15 days to about 24 hours (particularly from about 12 days to
about 36 hours or from about 10 days to about 48 hours), from
introduction into a physiological environment when incubated with
simulated physiological fluid at a temperature of about 37.degree.
C.
[0066] In some embodiments, the dressing 100, and particularly the
dressing layer 110, may optionally comprise one or more additional
materials. Such optional components may include, for example,
active materials such as preservatives, stabilizing agents,
plasticizers, matrix strengthening materials, dyestuffs, and
combinations thereof.
[0067] Additionally or alternatively, the dressing 100, and
particularly the dressing layer 110, may comprise one or more
additional active materials, for example, antimicrobial agents that
may be effective to aid in tissue healing. Non-limiting examples of
such active materials may include non-steroidal anti-inflammatory
drugs such as acetaminophen, steroids, antimicrobial agents such as
penicillins or streptomycins, antiseptics such as chlorhexidine,
growth factors such as fibroblast growth factor or platelet derived
growth factor, peptides, microRNA, antioxidants, and other
well-known therapeutic agents, alone or in combination. If present,
such active materials may typically be included at any effective
level that show therapeutic efficacy, while preferably not being at
such a high level as to significantly counteract any critical or
desired physical, chemical, or biological property of the dressing.
Depending upon the therapeutic goal, active material may be loaded
at a level of from about 10 wppm to about 10 wt % of a layer in
which it is present, for example, from about 50 wppm to about 5 wt
% or from about 100 wppm to about 1 wt %.
[0068] In some embodiments when antimicrobial agents are present,
the antimicrobial agents may comprise a safe and effective amount
of poly(hexamethylene biguanide) ("PHMB"), which is also known as
polyaminopropyl biguanid ("PAPB") and polyhexanide, having the
following general formula.
##STR00001##
[0069] PHMB can be a cationic broad spectrum antimicrobial agent.
PHMB may be synthesized by a variety of methods, including
polycondensation of sodium dicyanamide and hexamethylenediamine.
PHMB is commercially available from a variety of sources. In some
embodiments, the PHMB may be present in one or more of the dressing
layers at a level of from about 0.005 wt % to about 0.025 wt % of
each layer in which it is present, particularly from about 0.007 wt
% to about 0.2 wt % or from about 0.008 wt % to about 0.012 wt %,
or in some cases at about 0.01 wt %. In some embodiments, the PHMB
may be present in the dressing layer 110 at a level of from about
0.05 wt % to about 3 wt % of a layer in which it is present,
particularly from about 0.1 wt % to about 2.5 wt %, from about 0.3
wt % to about 2 wt %, from about 0.5 wt % to about 1.5 wt %, or in
some cases at about 1 wt %. In alternative embodiments, silver
compounds having antimicrobial efficacy may completely or partially
replace the PHMB, as desired. In alternative embodiments, silver
compounds having antimicrobial efficacy may completely or partially
replace the PHMB, as desired.
[0070] In some embodiments where CMC is not already present, CMC
may be added as a modifier for one or more characteristics of the
dressing 100 or dressing layer 110, for example, the rheological,
absorbency, and other structural characteristics. CMC may be
present in one or more layers of the dressing 100 at any level
appropriate to result in the desired absorbency, rheological, or
other structural characteristics of the dressing 100.
[0071] In some embodiments, the absorbent layer portion 145 of the
dressing layer 110, when an absorbent layer is present, may contain
a strengthening material, which can improve the handling
characteristics of the dressing 100, for example, by decreasing its
susceptibility to tearing. The strengthening material may comprise
non-gelling cellulose fibers in some examples. Such non-gelling
cellulose fibers may be substantially water insoluble and may be
produced from cellulose that has not been chemically modified to
increase water solubility, for example, as contrasted from
carboxymethyl cellulose or other cellulose ethers. Non-gelling
cellulose fibers are commercially available, such as under the
tradename TENCEL (sold by Lenzing AG). In some embodiments, such
fibers may be processed from a commercially-available continuous
length, by cutting into lengths from about 0.5 to about 5 cm or
from about 2 to about 3 cm in length. The non-gelling cellulose
fibers may be present in the absorbent layer 145 at any level
appropriate to result in desired physical characteristics of the
dressing layer 110 or of the dressing 100. In general, when
present, the non-gelling cellulose fibers may comprise from about
1% to about 55% of the layer by weight, particularly from about 5%
to about 40% of the layer by weight or from about 10% to about 25%
of the layer by weight. In some embodiments, if present, the
non-gelling cellulose fibers can be characterized as an additional
or alternative reinforcing fiber and can be present in reinforcing
fiber amounts.
[0072] In some embodiments, the dressing 100 may comprise one or
more additional layers. In various embodiments, such additional
layers may perform any of a variety of functions including, for
example, adherence of the dressing 100 to a tissue site or to
surrounding tissues, increasing structural rigidity of the dressing
100, imparting elastic recovery, protection from moisture or other
contaminants in the external environment, protection of a tissue
surface, delivery of one or more active or other materials to a
tissue surface, or combinations thereof. In various embodiments,
the additional layers may be conformable to a tissue surface, for
example, being capable of conforming such that the appropriate
surfaces of the dressing 100 are in substantial contact with a
tissue site 112.
[0073] For example, in the embodiment of FIG. 2, the dressing 100
comprises a backing layer 120, which may be positioned over the
dressing layer 110, to cover the dressing layer 110 at a tissue
site 112. The backing layer 120 may have a first or bottom surface
and a second or top surface. The backing layer 120 may support the
dressing layer 110, for example, such that a top surface of the
dressing layer 110 can be proximate to the bottom surface of the
backing layer 120. In some embodiments, the top surface of the
dressing layer 110 may be in contact with and adhered to the bottom
surface of the backing layer 120, for example via adherent layer
142.
[0074] In particular embodiments, the backing layer 120 of the
dressing 100 may extend beyond the boundaries or edges of the
dressing layer 110, so as to exhibit an exposed backing layer
margin, which may typically be exhibited on the bottom surface of
the backing layer 120. In some embodiments, the backing layer 120
may be non-adherent.
[0075] In some embodiments, the backing layer 120 may generally be
configured to provide a barrier to microbes, a barrier to external
contamination, and protection from physical trauma. For example,
the backing layer 120 may be constructed from a material that can
reduce evaporative losses and provide a fluid seal between two
components or two environments, such as between a therapeutic
environment and a local external environment. The backing layer 120
may be formed from a suitable material, such as a polymer, for
example, which may comprise or be an elastomeric film or membrane
that can provide a seal at a tissue site. In some embodiments, the
backing layer 120 may comprise or be a polyurethane. In some
embodiments, the backing layer 120 may have a high moisture-vapor
transmission rate (MVTR). For example, in such an embodiment, the
MVTR may be at least 300 g/m.sup.2 per twenty-four hours. For
example, the backing layer 120 may comprise a polymer drape, such
as a polyurethane film, that may be permeable to water vapor but
generally impermeable to liquid water. In some embodiments, the
backing layer 120 may have a thickness in the range of about from
about 15 to about 50 microns.
[0076] In some embodiments, the top surface of the dressing layer
110 may be in contact with and adhered to the bottom surface of the
backing layer 120. This adherence may, in some embodiments, result
from an adherent layer, such as adherent layer 142 in FIG. 2,
disposed between the dressing layer 110 and the backing layer 120,
thus constituting direct adherence. Such direct adherence means
that the adherent layer 142, or at least the portion disposed
between the dressing layer 110 and the backing layer 120, can be
comprised of one or more different kinds of physical or chemical
adhesive compositions. The adherent layer 142 or portion thereof
disposed between the dressing layer 110 and the backing layer 120,
in some embodiments, may not directly contact a tissue site. For
example, in embodiments with a backing layer margin extending
beyond the dressing layer 110, the adherent layer 142 may typically
extend out to cover all or part of the backing layer margin. In
such embodiments, the portion of the adherent layer on the margin
may adhere the dressing 100 to tissue proximate to a tissue site
112, such as epidermis 130 in FIG. 2. Adherents that may directly
contact tissue or that may be exposed to a treatment environment
can typically have additional requirements, such as
biocompatibility, and may be selected from a smaller list of
physical or chemical adhesive compositions.
[0077] In some embodiments, such as where an adherent layer 142 is
an external layer in the dressing 100, for example to adhere the
dressing 100 to epidermis 130, to sub-epidermal layer 131, or to a
tissue site 112, the adherent layer can be releasably coupled to a
release liner configured for removal before application to a tissue
site, for example.
[0078] Adherence between the dressing layer 110 and the backing
layer 120 may additionally or alternatively be indirect. For
example, in some embodiments with a backing layer margin extending
beyond the dressing layer 110, the adherent layer may be disposed
on the backing layer margin and extend further over some portion of
the dressing layer 110, such as the margin of the dressing layer
110. If this occurs without an adherent layer between the backing
layer 120 and the dressing layer 110, the adherent layer may be
said to indirectly adhere those layers, because those layers are
each adhered to the adherent layer but not directly to each other.
Such a configuration can allow an absorbent portion of the dressing
layer 110 to expand differentially from the backing layer 120, for
instance enabling relatively high levels of absorption of fluid
with additional degrees of freedom.
[0079] In particular embodiments, any adherent layers in the
dressing 100, for example whether coupled to the optional absorbent
layer 145, the manifolding layer 148, the backing layer 120, or any
other layer in the dressing 100, may comprise a hydrocolloid
material, a hydrogel, a silicone adhesive, a silicone gel, an
acrylic adhesive, a vegetable-based adhesive, an animal-based
adhesive, or a combination or copolymer thereof.
[0080] Additionally, in some embodiments, the dressing 100 may
further comprise one or more secondary layers, for example,
positioned between the dressing layer 110 and the backing layer
120. In some embodiments, a secondary layer may be an additional
manifolding layer, which may comprise fluid pathways interconnected
so as to improve distribution or collection of fluids. For example,
in some embodiments, a secondary layer may be a porous material
having a plurality of interconnected cells or pores. Examples of
suitable materials for the secondary manifolding layer may include
open-cell foam, such as reticulated foam, or porous tissue
collections. Other suitable porous material may include gauze or
felted mat, which generally include pores, edges, or walls adapted
to form interconnected fluid pathways. For example, in some
embodiments, a secondary layer may comprise or consist essentially
of foam having pore sizes in a range of 400-600 microns. In one
non-limiting example, a secondary layer may comprise or be
reticulated polyurethane foam.
[0081] In some embodiments having a secondary layer, the secondary
layer may comprise or be an absorbent layer or may be characterized
as exhibiting absorbency. For example, the secondary layer may
exhibit an absorbency of at least 3 g saline/g, particularly at
least 5 g saline/g, from 5 to 50 g saline/g, from 8 to 40 g
saline/g, or from 8 to 20 g saline/g. In some embodiments, the
secondary layer may be hydrophilic. In an example in which the
secondary layer may be hydrophilic, the secondary layer may also
wick fluid away from a dressing layer 110. In such embodiments, the
wicking properties of the secondary layer may draw fluid away from
dressing layer 110 by capillary flow or other wicking mechanisms.
An example of a hydrophilic foam is a polyvinyl alcohol, open-cell
foam. Other hydrophilic foams may include those made from or
containing a polyester, a polyether, or a polyurethane. Additional
or alternative foams that may exhibit hydrophilic characteristics
include hydrophobic foams that have been treated or coated to
provide hydrophilicity.
[0082] Also disclosed herein are methods of treating a tissue site,
for example, in the context of various therapies, such as
eliminating, minimizing, or reducing edema and/or increasing
interstitial fluid flow. In some embodiments, the tissue site may
be a compartmented tissue site, such as an overhang wound or a
peritoneal or abdominal cavity. In some embodiments, the tissue
site may be a surface tissue site, such as a burn, a graft, or a
post-operative wound. In some embodiments, the tissue site may be a
tunnel wound site, such as a puncture or a fistula.
[0083] In some embodiments, a therapy or treatment method may
comprise applying the wound filler 10 or the dressing layer 110
comprising a filler layer 160 to a tissue site. The wound filler 10
or dressing layer 110 may be used to treat any of a variety of
tissue sites, such as those occurring from trauma, surgery, or
disease. For example, the wound filler 10 or dressing layer 110 may
be placed within, over, on, or otherwise proximate to a tissue
site. Additionally, in some embodiments, a cover such as the
backing layer 120 may be placed over the dressing layer 110 and
sealed to an attachment surface near the tissue site. For example,
the backing layer 120 may be sealed to undamaged epidermis 130
peripheral to a tissue site 112. In some embodiments, the wound
filler 10 may be positioned and a dressing layer 110 may be
positioned after the wound filler 10 has been positioned. In some
embodiments, the backing layer 120 can provide a sealed therapeutic
environment proximate to a tissue site containing the wound filler
10 and/or the dressing layer 110, thereby substantially isolating
the tissue site from the external environment.
[0084] In some embodiments, the therapy or treatment method may
comprise applying a wound filler 10, or a dressing 100 containing a
filler layer 160, to a tissue site for a period of time. FIGS.
1A-1F show an illustrative embodiment of a wound filler 10, and
FIG. 2 shows an illustrative embodiment of a dressing 100
containing a filler layer 160, that may be used in such a
treatment. Though FIG. 2 depicts the dressing 100 being deployed at
a tissue site 112, such as a burn or a graft wound, the dressing
100 may additionally or alternatively be used in conjunction with
other types of tissue sites, such as a post-operative incision,
compartmented tissue, a tunnel wound, or the like. Similarly,
though FIG. 2 depicts a therapy or treatment method without
application of negative pressure and without provision for an
instillation fluid, the dressing 100, or a wound filler 10, may
additionally or alternatively be used or be modified for use in
conjunction with other therapies or treatments, such as those
including application of negative pressure, those including
provision of an instillation fluid, or those including both.
[0085] Referring again to FIG. 2, dressing 100 is shown as
comprising the dressing layer 110, the backing layer 120, and an
adherent layer 142 coupling the dressing layer 110 and the backing
layer 120. Dressing layer 110 includes an assembly of a manifolding
layer 148 and a filler layer 160 containing an array of
interconnected ovules 162 and fluid pathways extending
substantially perpendicular through the array. In the example of
FIG. 2, the dressing layer 110 is shown as also including an
optional absorbent layer, such as absorbent layer 145. The filler
layer 160 is shown as being in contact with the tissue site 112,
which is illustrated as being a surface wound transecting the
epidermis 130 and extending into layer 131. Layer 131 may represent
the dermis or any dermal tissue below the epidermis 130, or it may
represent one or more other internal bodily structures, such as
muscles, tendons, ligaments, cartilage, bones, connective tissue,
adipose tissue, neural tissue, vascular tissue, connective tissue,
internal organs, or the like.
[0086] FIG. 3 is a simplified functional block diagram of an
example embodiment of a therapy system 300 that can provide
negative-pressure therapy, optionally along with instillation of
topical treatment solutions, to a tissue site in accordance with
this specification.
[0087] The therapy system 300 may include a therapy unit 304 and a
treatment device 301 including a dressing 100. In some embodiments,
the therapy unit 304 may include a negative-pressure source, such
as negative-pressure source 306, optionally a fluid source, such as
fluid source 308, and a regulator or controller 309. In other
embodiments, the therapy unit 304 may include the negative-pressure
source 306, while the optional fluid source 308 and/or the
controller 309 may be freestanding, separate units. The therapy
system 300 may optionally also include additional components, such
as a container 310, which may be coupled to or in fluid
communication with at least the treatment device 301, the dressing
100, the therapy unit 304, and the negative-pressure source 306,
whether directly or indirectly. In some embodiments, the treatment
device 301 may include a wound filler 10, separate from but in
addition to the dressing 100. In some embodiments, a filler layer
160 may be integral with the dressing 100.
[0088] Components of the therapy system 300 may be fluidly coupled
to each other to provide a path for transferring fluids (i.e.,
liquid and/or gas) between the components. For example, components
may be fluidly coupled through a fluid conductor, such as a tube. A
"tube," as used herein, broadly includes a tube, pipe, hose,
conduit, or other structure with one or more lumina adapted to
convey a fluid between two ends. Typically, a tube is an elongated,
cylindrical structure with some flexibility, but the geometry and
rigidity may vary. In some embodiments, components may also be
coupled by virtue of physical proximity, being integral to a single
structure, or being formed from the same piece of material.
Moreover, some fluid conductors may be molded into or otherwise
integrally combined with other components. Coupling may also
include mechanical, thermal, electrical, or chemical coupling (such
as a chemical bond) in some contexts. For example, a tube may
mechanically and fluidly couple the treatment device 301 to the
therapy unit 304 in some embodiments. In general, components of the
therapy system 300 may be coupled directly or indirectly.
[0089] The negative-pressure source 306 may be configured to be
coupled to a distribution component, such as the dressing 100, for
example. In general, a distribution component may refer to any
complementary or ancillary component configured to be fluidly
coupled to a negative-pressure supply in a fluid path between a
negative-pressure supply and a tissue site. A distribution
component is preferably detachable, and may be disposable,
reusable, or recyclable. For example, the dressing 100 of the
treatment device 301 may be fluidly coupled to the
negative-pressure source 306 of the therapy unit 304, as
illustrated in FIG. 3. In some embodiments, the treatment device
301 may include the dressing 100, as well as additional tissue
interfaces, fluid conduits, and/or a cover. In some embodiments, a
dressing interface may facilitate coupling the negative-pressure
source 306 to the dressing 100 of the treatment device 301. For
example, such a dressing interface may be a SENSAT.R.A.C..TM. Pad,
VERAT.R.A.C..TM. Pad, or VERAT.R.A.C..TM. Duo Tubing Set available
from KCI of San Antonio, Tex.
[0090] The fluid mechanics of using a negative-pressure source to
reduce pressure in another component or location, such as within a
sealed therapeutic environment, can be mathematically complex.
However, the basic principles of fluid mechanics applicable to
negative-pressure therapy and instillation are generally well-known
to those skilled in the art, and the process of reducing pressure
may be described illustratively herein as "delivering,"
"distributing," or "generating" negative pressure, for example.
[0091] In general, exudates and other fluids flow toward lower
pressure along a fluid path. Thus, the term "downstream" typically
implies something in a fluid path relatively closer to a source of
negative pressure or further away from a source of positive
pressure. Conversely, the term "upstream" implies something
relatively further away from a source of negative pressure or
closer to a source of positive pressure. Similarly, it may be
convenient to describe certain features in terms of fluid "inlet"
or "outlet" in such a frame of reference. This orientation is
generally presumed for purposes of describing various features and
components herein. However, the fluid path may also be reversed in
some applications (such as by substituting a positive-pressure
source for a negative-pressure source) and this descriptive
convention should not be construed as a limiting convention.
[0092] "Negative pressure" generally refers to a pressure less than
a local ambient pressure, such as the ambient pressure in a local
environment external to a sealed therapeutic environment provided
by the treatment device 301 or the dressing 100. In many cases, the
local ambient pressure may also be the atmospheric pressure at
which a tissue site is located. Alternatively, the pressure may be
less than a hydrostatic pressure associated with tissue at the
tissue site. Unless otherwise indicated, values of pressure stated
herein are gauge pressures. Similarly, references to increases in
negative pressure typically refer to a decrease in absolute
pressure, while decreases in negative pressure typically refer to
an increase in absolute pressure. While the amount and nature of
negative pressure applied to a tissue site may vary according to
therapeutic requirements, the pressure is generally a low vacuum,
also commonly referred to as a rough vacuum, between -5 mm Hg (-667
Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are
between -50 mm Hg (-6.67 kPa) and -300 mm Hg (-39.9 kPa).
[0093] A negative-pressure supply, such as the negative-pressure
source 306 of the therapy unit 304, may be a reservoir of air at a
negative pressure, or may be a manual or electrically-powered
device that can reduce the pressure in a sealed volume, such as a
vacuum pump, a suction pump, a wall suction port available at many
healthcare facilities, or a micro-pump, for example. A
negative-pressure supply may be housed within or used in
conjunction with other components, such as sensors, processing
units, alarm indicators, memory, databases, software, display
devices, or user interfaces that further facilitate therapy, such
as through the use of therapy unit 304. A negative-pressure supply
may also have one or more supply ports configured to facilitate
coupling and de-coupling the negative-pressure supply to one or
more distribution components.
[0094] In some embodiments, the therapy system 300 may include one
or more sensors, such as a pressure sensor, an electric sensor, a
temperature sensor, a pH sensor, a relative humidity sensor, or a
combination thereof, to measure one or more operating parameters
and provide feedback signals to the controller 309 indicative of
the operating parameters. In some embodiments if present, the
pressure sensor may also be coupled, or configured to be coupled,
to a distribution component and to the negative-pressure source
306, which may, for example, include wireless connection.
Additionally or alternatively, a sensor may be configured to
provide information to a person, who can then manually control one
or more operating parameters externally. Sensors, such as pressure
sensors or electric sensors, are generally known in the art as any
apparatus operable to detect or measure a physical phenomenon or
property, and generally provide a signal indicative of the
phenomenon or property that is detected or measured. If present, a
pressure sensor may be a transducer configured to measure pressure
in a pneumatic pathway and convert the measurement to a signal
indicative of the pressure measured, in some embodiments. If
present, for example, a pressure sensor may be a piezoresistive
strain gauge in some embodiments. If present, an electric sensor
may optionally measure operating parameters of the
negative-pressure source 306, such as voltage or current, in some
embodiments. Also if present, the signals from a pressure sensor
and an electric sensor may be suitable as an input signal to the
controller 309, but some signal conditioning may be appropriate in
some embodiments. For example, in such embodiments the signal may
need to be filtered or amplified before it can be processed by the
controller 309. Typically in such embodiments, the signal is an
electrical signal, but may be represented in other forms, such as
an optical signal. If a sensor is meant to monitor conditions at or
near a tissue site or sealed volume, then it may be advantageous
for the sensor to be placed as close as practical or possible to
the site(s) desired to be monitored. In various embodiments, if
present, a pressure sensor may be placed in a conduit in fluid
communication with the negative-pressure source 306 but proximate
to the sealed volume, for example on or in the wound filler 10, if
present, or near, on, or in one or more layers of the dressing
100.
[0095] The therapy system 300 may optionally also include a source
of instillation fluid or solution. For example, a fluid source 308
may be fluidly coupled to the treatment device 301, and thus the
dressing 100, as illustrated in the example embodiment of FIG. 3.
The fluid source 308 may be fluidly coupled to a positive-pressure
source, the negative-pressure source 306, or both in some
embodiments. A regulator, such as an instillation regulator, may
also be fluidly coupled to the fluid source 308 and the treatment
device 301 to ensure proper dosage of instillation solution to a
tissue site. For example, the instillation regulator may comprise a
piston that can be pneumatically actuated by the negative-pressure
source 306 to draw instillation solution from the fluid source 308
during a negative-pressure interval and to instill the solution to
the dressing 100 during a venting interval. Additionally or
alternatively, the controller 309 may be coupled to the
negative-pressure source 306, the positive-pressure source, or
both, to control dosage of instillation solution to a tissue site.
In some embodiments, an instillation regulator may be fluidly
coupled to the negative-pressure source 306 through the treatment
device 301, and thus through the dressing 100.
[0096] The fluid source 308 may also be representative of a
container, canister, pouch, bag, or other storage component, which
can provide a solution for instillation therapy. Compositions of
solutions may vary according to a prescribed therapy, but examples
of solutions that may be suitable for some prescriptions include
hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based
solutions, biguanides, cationic solutions, saline solutions, and
isotonic solutions.
[0097] A controller, such as the controller 309, may be a
microprocessor or computer programmed to operate one or more
components of the therapy system 300, such as the negative-pressure
source 306 and the fluid source 308. In some embodiments, for
example, the controller 309 may be a microcontroller, which
generally comprises an integrated circuit containing a processor
core and a memory programmed to directly or indirectly control one
or more operating parameters of the therapy system 300. Operating
parameters may include the power applied to the negative-pressure
source 306, the pressure generated by the negative-pressure source
306, or the pressure distributed to the treatment device 301, for
example. Additional operating parameters may include the power
applied to the fluid source 308, flow rate of instillation fluid
provided by the fluid source 308, or volume of fluid distributed to
the treatment device 301. The controller 309 is also preferably
configured to receive one or more input signals, such as a feedback
signal, and programmed to modify one or more operating parameters
based on the input signals.
[0098] In some embodiments, the negative-pressure source 306, fluid
source 308, controller 309, and container 310 may be integrated
within a single therapy unit, such as therapy unit 304. For
example, the therapy system 300 may therefore include the treatment
device 301 along with a therapy unit 304 such as a V.A.C.ULTA.TM.
therapy unit, V.A.C.INSTILL.TM. wound therapy system,
INFOV.A.C..TM. therapy unit, each available from KCI of San
Antonio, Tex., or other suitable therapy units or systems. For
example, in some embodiments, the therapy unit 304 may comprise or
consist essentially of a V.A.C.ULTA.TM. unit, which may include
software modules specific to negative-pressure therapy in
combination with fluid instillation therapy, and for use with
specific types of tissue sites. Alternatively, any other device
capable of providing negative-pressure therapy may be suitable
along with any mechanical fluid instillation device, or any
negative-pressure therapy device in combination with a
manually-managed fluid instillation source, such as a gravity-fed
fluid vessel, manual fluid pump, or monitored IV bag or bottle.
[0099] FIG. 4 is a schematic diagram illustrating additional
details that may be associated with some embodiments of the
treatment device 301. The treatment device 301 of FIG. 4 is applied
to another example of the tissue site 112. In this illustrative
embodiment, the tissue site 112 may include tissue in a body
cavity, such as an abdominal cavity. The tissue site 112 may
include abdominal contents or tissue proximate the abdominal
cavity. Treatment of the tissue site 112 may include removal of
fluids, e.g., ascites, protection of the abdominal cavity, or
negative-pressure therapy.
[0100] As shown in FIG. 4, the dressing 100 may be disposed near,
or within, a tissue site 112, which may be a compartmented site
such as a peritoneal or an abdominal cavity, in order to treat the
tissue site 112. In some abdominal cavities, for example, the
dressing 100 may be supported by the abdominal contents, which can
be generalized to most compartmented tissue sites. As depicted, a
first portion of the dressing 100 may be positioned in or proximate
to a first paracolic gutter 315, and a second portion of the
dressing 100 may be placed in or proximate to a second paracolic
gutter 317. The first paracolic gutter 315 and the second paracolic
gutter 317 may each be, for example, an open space on opposing
sides of the abdominal cavity among the abdominal contents. The
first paracolic gutter 315 may be laterally disposed from the
second paracolic gutter 317 or otherwise located on an opposite
side of the tissue site 112 from the second paracolic gutter 317.
Although FIG. 4 depicts the treatment device 301 deployed at an
abdominal cavity, the treatment device 301 and therapy system 300
may be used at other types of tissue sites, for example in which
tissue contacts the treatment device 301, or particularly the
dressing 100, on both a first surface and a second surface facing
away from the first surface. Non-limiting examples of such tissue
sites can include compartmented wounds, overhang wounds, tunnel
wounds, flaps, or the like.
[0101] In some embodiments, the treatment device 301 may further
include a cover 320 for providing a fluid seal over the tissue site
112. In some embodiments, the cover 320 may generally be configured
to provide a barrier to microbes, a barrier to external
contamination, and protection from physical trauma. For example,
the cover 320 may be constructed from a material that can reduce
evaporative losses and provide a fluid seal between two components
or two environments, such as between a therapeutic environment and
a local external environment. The cover 320 may be formed from a
suitable material, such as a polymer, for example, which may
comprise or be an elastomeric film or membrane that can provide a
seal at a tissue site. In examples involving application of
negative pressure to a tissue site, the cover can provide a seal
adequate to maintain negative pressure at a tissue site for a given
negative-pressure source 306. In some embodiments, the cover 320
may comprise or consist essentially of polyurethane. In some
embodiments, the cover 320 may have a high moisture-vapor
transmission rate (MVTR). For example, in such an embodiment, the
MVTR may be at least 300 g/m.sup.2 per twenty-four hours. For
example, the cover 320 may comprise a polymer drape, such as a
polyurethane film, that may be permeable to water vapor but
generally impermeable to liquid water. In some embodiments, the
cover 320 may have a thickness in the range of about from about 15
to about 50 microns. For permeable materials, the permeability
generally should be low enough that a desired negative pressure may
be maintained.
[0102] An attachment device, such as attachment device 332, may be
used to attach the cover 320 to an attachment surface of a tissue
site 112, such as the epidermis 130 of a patient. The attachment
device 332 may be used to attach the cover 320 to a gasket, or
another sealing member or cover. The attachment device 332 may take
any of a variety of suitable forms. For example, an attachment
device may be a medically-acceptable, pressure-sensitive adhesive
that extends about a periphery, a portion, or an entire sealing
member or cover. In some embodiments, for example, some or all of
the cover 320 may be coated with an adherent layer, such as
comprising an acrylic adhesive, having a coating weight between 25
and 65 grams per square meter (g.s.m.). Thicker adhesives, or
combinations of adhesives, may be applied in some embodiments to
improve the seal and reduce leaks. Other example embodiments of an
attachment device may include a double-sided tape, paste,
hydrocolloid, hydrogel, silicone gel, or organogel.
[0103] The illustrative systems and devices herein may optionally
allow for the irrigation and washing out of a tissue site 112, for
example a compartmented site such as a peritoneal or an abdominal
cavity, with the controlled and regulated introduction of fluid. In
some instances, it may be necessary to wash or cleanse a
contaminated abdominal cavity, for example as a result of a
perforated colon or sepsis. The therapy system 300 can provide
means to instill fluid into an open abdomen to cleanse the
abdominal contents, including reaching areas such as the small
bowel loops, pancreas, etc. Additionally, the treatment device 301
and the therapy system 300 may provide temporary closure to an open
abdomen, while optionally allowing for removal of fluid, reduction
of edema, and/or increase in interstitial fluid flow. Thus, the
therapy system 300 may provide the capability of performing
washouts of a tissue site, such as a peritoneal or abdominal
cavity, without having to repeatedly remove one or more dressings
applied to the tissue site of a patient or bringing the patient
into the operating room for manual fluid introduction procedures.
The therapy system 300 may thus be able to provide a controlled and
regulated full abdominal wash, for example via instillation of a
therapeutic fluid, as well as have the capability to provide a
targeted wash to certain areas within the abdomen when required.
Some embodiments of the therapy system 300, and more particularly
the dressing 100, may also provide support and maintenance of the
fascial domain of an abdominal cavity, for example, and provide
overall protection to the abdominal contents.
[0104] In some embodiments, the therapy system 300 may also include
an interface for fluidly connecting the dressing 100 and other
portions of the treatment device 301 to a conduit 334, as shown in
FIG. 4. The interface may include a connector, which may comprise
or be a part of a negative-pressure connector subsystem.
Alternatively, the interface may be partially or fully embedded
within a portion of the dressing 100, or configured in any other
way possible for fluidly connecting the treatment device 301 to a
therapy unit, such as the therapy unit 304 of FIG. 3. The conduit
334 may be fluidly coupled to negative-pressure source 306 and/or
fluid source 308 of the therapy unit 304 for providing negative
pressure and/or treatment fluid, respectively, to the treatment
device 301. In some embodiments, the conduit 334 may include two
substantially parallel, fluidly-isolated conduits, one of which for
fluidly coupling the treatment device 301 to the negative-pressure
source 306 and the other for fluidly coupling the treatment device
301 to the fluid source 308. Thus, in some embodiments, the conduit
334 may be a multi-lumen conduit with both a negative-pressure
lumen 335 and a fluid withdrawal lumen 337. In some other
illustrative embodiments, the conduit 334 may be replaced with two
separate conduits, one containing a negative-pressure lumen and the
other containing a fluid withdrawal lumen. In embodiments enabling
fluid instillation, fluid withdrawal lumen 337 can be temporarily
or intermittently repurposed to provide instillation fluid, instead
of withdrawing fluid, in which situations fluid withdrawal lumen
337 can alternatively be referred to as a fluid supply lumen. In
other embodiments enabling fluid instillation, the conduit 334 may
be a multi-lumen conduit with a negative-pressure lumen 335, a
fluid withdrawal lumen 337 in fluid communication with container
310, and a separate fluid supply lumen (not pictured in FIG. 4) in
fluid communication with fluid source 308, which may be separate
from container 310. In such multi-lumen embodiments, the
negative-pressure, fluid withdrawal, and fluid supply lumens may be
together within the same conduit 334 or may be in three separate
conduits or in two separate conduits, for example with the fluid
supply lumen in one conduit and the negative-pressure lumen 335 and
the fluid withdrawal lumen 337 together in the other conduit.
[0105] In some embodiments, the therapy system 300 may further
include a filler material 340, such as a portion of foam, disposed
between the liquid-impermeable layer 351 and the cover 320. The
filler material 340 may be part of the interface and may be sized
to fill the portion of abdominal volume beneath or surrounding an
incision or opening into abdomen from the skin layers, such as a
portion of abdominal cavity. In some embodiments, the filler
material 340 may contain within it, or may itself serve as, a
distribution manifold for negative pressure. For example, in some
embodiments, the filler material 340 may be positioned between the
liquid-impermeable layer 351 and the cover 320, and a negative
pressure lumen or conduit, such as negative-pressure lumen 335, may
be pneumatically connected to the cover 320. As a result, fluid
removal may occur from the layers of the treatment device 301
through the filler material 340 positioned atop liquid-impermeable
layer 351, and into the negative-pressure lumen 335. In some
embodiments, the filler material may include a three-dimensional
woven or non-woven fabric, such as TDL2 or TL4, commercially
available from Libeltex of Meulebeke, Belgium, or 3DXD or 4DXD
spacer fabrics, commercially available from Baltex of Derbyshire,
England, or reticulated polyurethane foam such as found in
GRANUFOAM.TM. Dressing or V.A.C. VERAFLO.TM. Dressing, both
available from KCI of San Antonio, Tex.
[0106] In FIG. 4, the dressing 100 is shown as comprising an
assembly of a manifolding layer 148 and a filler layer 160 made
from an array of interconnected ovules 162 with a plurality of
fluid pathways extending through the array, between the ovules.
Although not depicted in FIG. 4, an absorbent layer, similar to the
absorbent layer 145 shown in FIG. 2, may be included in some
embodiments as an optional secondary layer of the dressing 100. If
present, in some embodiments, an absorbent layer may be positioned
between manifolding layer 148 and filler layer 160. Additionally or
alternatively in some embodiments, if present, an absorbent layer
may be positioned on the manifolding layer 148 on a surface
opposite the filler layer 160 and may or may not be coupled to the
manifolding layer 148.
[0107] By virtue of the fluid removal application of the treatment
device 301, facilitated by fluid connection to the
negative-pressure source 306, the manifolding layer 148, but more
generally the assembly further including filler layer 160, may
individually and collectively be configured to allow fluid removal
and optionally also to allow fluid instillation. Thus, the
manifolding layer 148 in particular may comprise fluid pathways,
such as fluid removal pathways 350, interconnected so as to improve
distribution or collection of fluids. Manifolding layer 148 may be
made of a porous material having a plurality of interconnected
cells or pores. Such manifolding materials may promote development
of granulation tissue at a tissue site, particularly when pressure
is reduced within a sealed therapeutic environment. In some
embodiments, however, increased development granulation tissue at a
tissue site may not be an objective, or granulation ingrowth into
portions of the dressing may be reduced, inhibited, or prevented.
For example, the dimensions, shape, or chemical composition of the
protrusions from the ovules 162 in the filler layer 160, and/or the
dimensions or shape of the fluid pathways between the ovules 162 in
the filler layer 160, may assist in reducing, inhibiting, or
preventing granulation ingrowth into portions of the dressing 100
or the treatment device 301.
[0108] The dressing 100 may include one or more liquid-impermeable
layers, such as liquid-impermeable layer 351. The
liquid-impermeable layer 351 may be formed with fenestrations 353.
"Liquid-impermeable" with respect to "liquid-impermeable layers"
means that the layers are formed with a liquid-impermeable
material. Thus, although formed with a liquid-impermeable material,
the layer may be liquid-permeable when fenestrated, but nonetheless
is referred to as a liquid-impermeable layer. The fenestrations 353
may take many shapes or combinations of shapes, including circular
apertures, elliptical apertures, rectangular openings, or polygons,
for example. The fenestrations 353 are presented in this
illustrative embodiment as slits, or linear cuts. In some
embodiments, the liquid-impermeable layer 351 may be sealingly
coupled to the assembly of the manifolding layer 148 and the filler
layer 160 in any suitable manner, for example, without limitation,
through chemical means or physical means or both, such as by
welding, bonding, adhesives, cements, or other bonding mechanisms.
This sealing coupling of the liquid-impermeable layer 351 may
include wrapping around portions of the assembly, for example
covering all exposed surfaces of the manifolding layer 148 or
covering all surfaces of the assembly except for the filler layer
160, as shown in FIG. 4. The liquid-impermeable layer 351 may be
adapted to be positioned between otherwise exposed surfaces of the
manifolding layer 148 and the tissue site 112. Additionally or
alternatively, if the assembly of layers includes an absorbent
layer disposed on a surface of the manifolding layer 148 not facing
toward the filler layer 160, then the liquid-impermeable layer 351
may be adapted to be positioned between otherwise exposed surfaces
of the absorbent layer and the tissue site 112. In some
embodiments, liquid-impermeable layers may function to distance
other layers, such as manifolding layers, from direct contact with
a tissue site, for example to reduce, inhibit, or prevent
granulation ingrowth into those layers. The liquid-impermeable
layer 351 may comprise a non-adherent material, such as a medical
drape, capable of inhibiting tissue from adhering to the
non-adherent material. For example, in some embodiments, the
liquid-impermeable layer 351 may comprise a breathable polyurethane
film.
[0109] Although not necessarily depicted in FIG. 4, a therapy
method including fluid instillation can occur by periodically
stopping application of negative pressure through the fluid
withdrawal lumen 337 and initiating liquid supply through the same
lumen, which can then alternatively be termed a fluid supply lumen.
The negative-pressure lumen 335 may or may not experience an
immediate halt in negative pressure application in such fluid
instillation embodiments. In such embodiments, the manifolding
layer 148 can function both as fluid removal assembly and the
optional fluid installation matrix, thereby enabling instillation
fluid to be provided to the chamber 355, through the fenestrations
353 in the liquid-impermeable layer 351 and ultimately to the
tissue site 112.
[0110] As shown in FIG. 4, the sealing coupling between the
liquid-impermeable layer 351 and the assembly of the manifolding
layer 148 and the filler layer 160 may form a chamber 355. In some
embodiments, the chamber 355 may enable the manifolding layer 148
to more efficiently communicate negative pressure and to allow
removal of fluids such as exudates from the tissue site 112, and
optionally also to function as an instillation matrix to deliver
instillation fluid to the tissue site 112. These manifolding
functions of the manifolding layer 148 may be seen in the
tortuosity of the fluid removal pathways 350 that flow through the
fenestrations 353 of the liquid-impermeable layer 351, into the
chamber 355, optionally also through the fluid pathways defined by
interconnected ovules 162 in filler layer 160, into the manifolding
layer 148, and into fluid removal tubes positioned in a central
region of the manifolding layer 148 and which are fluidly connected
to the fluid withdrawal lumen 337.
[0111] In some embodiments, the plurality of fluid removal pathways
350 may be fluidly coupled to a fluid removal hub 352, which is
optional but depicted in FIG. 4. The optional fluid removal hub 352
may serve as a distribution mechanism for communicating negative
pressure to each of the fluid removal pathways 350 from the
interface and the negative-pressure source 306. The fluid removal
pathways 350 may take the form of numerous different shapes or be
formed from a variety of materials. Multi-lumen tubes may
additionally or alternatively make up a portion of the fluid
removal pathways 350. Each of the different forms and
configurations of fluid removal pathways 350 may also apply to
fluid delivery tubes or to an instillation matrix, as applicable,
especially in embodiments in which instillation fluid and negative
pressure are not alternated using similar pathways but in reverse
directions.
[0112] Alternatively, as shown in FIG. 5, the optional fluid
instillation system can be integral with but separate from the
application of negative pressure for fluid collection. In some
therapy embodiments, negative pressure can be applied at the same
time as fluid is instilled, meaning that fluid withdrawal pathways
and fluid supply pathways may need to be separated. For example, in
FIG. 5, negative pressure can be applied to tissue site 112 by
negative-pressure source 306 through fluid removal pathways in the
manifolding layer 148 in chamber 355 and through fluid withdrawal
lumen 337 into a container, such as container 310. Fluid or
medicament can simultaneously be provided by fluid source 308
through fluid supply lumen 338 and through fluid supply pathways
via a plurality of fluid delivery tubes 358 in chamber 380.
Although treatment device 301 may be adapted to simultaneously
provide fluid or medicament with negative pressure, it is still
contemplated that the therapy system 300 shown in FIG. 5 may be
operated to alternate application of negative pressure and
instillation of fluid, as desired.
[0113] In the example of FIG. 5, the fluid delivery tubes 358 and
optional distribution hub 361 may be considered components of an
instillation matrix and may be constructed of a variety of
different materials, such as soft medical-grade silicone or PVC
tubing material. The plurality of fluid delivery tubes 358 may vary
in size, based on the particular size and application of the
treatment device 301, as well as the conditions of the tissue site
112 to which the treatment device 301 is to be applied. For
example, the fluid delivery tubes 358 may have an inner diameter of
between 0.5 mm and 4 mm. In some embodiments, the fluid delivery
tubes 358 may have an inner diameter of between 1 mm and 2 mm. The
rather small size of the fluid delivery tubes 358 may be conducive
for avoiding patient discomfort during therapy as well as ease of
removal of the treatment device 301 following completion of
therapy.
[0114] In some embodiments, the fluid removal tubes may
additionally function to communicate negative pressure and draw
fluids through both the ends as well as along the lengths of the
fluid removal tubes. For example, some embodiments of the fluid
removal tubes connected to fluid removal hub 352 may include open
ends as well as openings or apertures, such as removal pathway
apertures, along the length of the fluid removal tubes. In some
embodiments, the fluid delivery tubes 358 may only have open ends,
such as delivery ends, and may otherwise be fluidly isolated from
the surroundings along the length of the fluid delivery tubes 358.
In some embodiments, the treatment device 301 may be offered in a
single size with the option to cut and remove portions of the
treatment device 301 to reduce its size, thus potentially
shortening the length of the fluid delivery tubes 358, as required
on an individual patient basis. By having openings of the fluid
delivery tubes 358 only at the ends of the individual tubes,
greater levels of customization may be achieved since the fluid
delivery tubes or instillation matrix do not rely on a set length
of the fluid delivery tubes 358 or number or size of perforations
along the fluid delivery tubes 358 to evenly distribute
instillation fluid. In other embodiments, the fluid delivery tubes
358 may exhibit a plurality of perforations to enable more even
distribution of instillation fluid across the chamber 355 and
amongst the tissue site 112. In still other embodiments, rather
than having open ends for delivering instillation fluid to a tissue
site, each of the fluid delivery tubes 358 may instead have closed
ends, such as delivery tube closed ends, and thus may include
openings or perforations, such as delivery tube perforations. The
fluid delivery tubes 358 may include both open ends as well as
perforations along their lengths, should the particular need or
application arise.
[0115] The fluid delivery tubes 358, as well as any other
components of an instillation matrix, may be adapted to deliver
fluids across the tissue site 112 in a substantially uniform
manner. For example, each of the fluid delivery tubes 358, the
delivery ends, and the delivery tube perforations may be adapted to
provide substantially the same back-pressure. Such a configuration
may prevent fluid from traveling more freely through or otherwise
favoring one or more of the fluid delivery tubes 358 over another
one or more of the fluid delivery tubes 358. Herein, back-pressure
may refer to an increase in localized pressure caused by a
resistance to fluid flow, such as through the confined space of a
lumen or aperture. Back-pressure may result from the geometric
configuration and material properties of the confined space, such
as, without limitation, the size of the space, the presence and
shape of bends or joints in the space, surface finishes within the
space, and other characteristics. In some embodiments, a fluid hub,
such as distribution hub 361, may not be necessary if the
perforations along the lengths of the fluid delivery tubes 358 are
sized to provide a substantially even distribution of fluid
throughout the tissue site 112. Consistency among the size and
configuration of the fluid delivery tubes 358, and the number and
size of the delivery ends and delivery tube perforations in each of
the fluid delivery tubes 358, for example, may enhance the
uniformity of fluid delivery to the tissue site 112.
[0116] In some embodiments, the fluid delivery tubes 358 may have a
cylindrical tube shape and may have an internal diameter between
about 2 millimeters and about 6 millimeters. In some other
embodiments, the fluid delivery tubes 358 may have an alternate
tubing profile, where a lower-profile, or "flatter" tubing profile
may be used to increase user comfort when the treatment device 301
is in place in a tissue site 112. The delivery apertures, in some
embodiments, may have a diameter between about 0.1 millimeters and
about 0.8 millimeters. Sizing the internal diameter or
cross-section of the fluid delivery tubes 358 substantially larger
than the size, cross-section, or diameter of the delivery ends and
the delivery tube perforations may provide a substantially uniform
pressure within each of the fluid delivery tubes 358. In such an
embodiment, fluid flow velocity within the fluid delivery tubes 358
may be relatively low or substantially static in comparison to the
relatively high fluid flow velocity through the delivery
apertures.
[0117] Although not shown in the accompanying figures, in some
embodiments, the fluid delivery tubes 358 may be arranged in the
form of a grid, for example extending outward from a central
distribution hub 361, such as radially, with tubing segments that
fluidly connect each of the outwardly-extending fluid delivery
tubes 358. Perforations may exist along any or all portions of the
outwardly-extending fluid delivery tubes 358, as well as the
connecting tubing segments, in such embodiments.
[0118] In some embodiments, such as shown in FIG. 5, the treatment
device 301 may comprise a distribution material for assisting with
distributing the instillation fluid, such as filler material 340,
as a complement to or an element of the distribution hub 361.
Whether the distribution hub is elongate, cylindrical in shape, or
bell-shaped, or comprises a fitting, such as a tube, tubular
fitting, pipe, barbed connection, or similar structure, the
distribution hub 361 or filler material 340 may generally be
configured to be fluidly coupled between the fluid supply lumen 338
of the conduit 334 and the fluid delivery tubes 358.
[0119] In some embodiments, such as shown in FIG. 5, the second
liquid-impermeable layer 375 may be disposed atop first
liquid-impermeable layer 351 on a surface facing opposite from the
manifolding layer 148. In this configuration, the first
liquid-impermeable layer 351 and the second liquid-impermeable
layer 375 may be coupled at their edges, defining chamber 380
between. In some embodiments, each of the liquid-impermeable layers
may be formed from a polyurethane material, for example each having
a thickness of between 25 .mu.m and 500 .mu.m.
[0120] Referring primarily to FIG. 5, the treatment device 301 may
be adapted to provide negative pressure from the negative-pressure
source 306 of the therapy unit 304 to a tissue site 112, such as an
abdominal cavity, and to collect and transport fluid extracted from
the tissue site 112. Additionally, the treatment device 301 may
also be adapted to deliver a fluid, such as a treatment fluid or
medicament, from the fluid source 308 of the therapy unit 304 to
the tissue site 112. In some embodiments, the dressing 100 may
include multiple liquid-impermeable layers, or visceral protective
layers, which protect the underlying abdominal contents of the
tissue site 112. For example, in some embodiments, the dressing 100
may include a first liquid-impermeable layer 351 having
fenestrations 353. In addition, in embodiments having simultaneous
capability to provide negative pressure and fluid instillation, the
dressing 100 may include a second liquid-impermeable layer 375.
Though shown in FIG. 5 as containing fenestrations 353 for
promoting fluid removal throughout an abdominal cavity, the first
liquid-impermeable layer 351 may contain fenestrations only at the
outer edges of the layer(s) or may contain no fenestrations.
Similarly, though shown in FIG. 5 as having a plurality of
fenestrations 377, the second liquid-impermeable layer 375 may
alternatively exhibit fenestrations only at the outer edges of the
second liquid-impermeable layer 375 or no fenestrations at all,
thereby partially or totally allowing for the instillation liquid
to take a circuitous path out of the chamber 380 through
fenestrations 377, among the abdominal contents, around the
dressing 100, back in through the assembly of manifolding layer 148
and filler layer 160, optionally into chamber 355, and through the
fluid removal pathways 350 into the fluid removal tubes toward the
fluid removal hub 352.
[0121] Referring again to FIG. 5, an interface may provide both a
negative-pressure connection as well as a fluid supply connection
to the treatment device 301. The interface may be sized, shaped, or
otherwise adapted to fluidly connect a negative-pressure lumen 335
and a fluid withdrawal lumen 337 of the conduit 334, as well as a
separate fluid supply lumen 338 if desired, to the treatment device
301 in any suitable manner. In some embodiments, the interface may
fluidly couple the negative-pressure lumen 335 and the fluid supply
lumen 338 through the cover 320. For example, one or more sealing
member apertures may be disposed through the cover 320 to provide
fluid communication and access to the components of the treatment
device 301 positioned within a sealed space involving the tissue
site 112.
[0122] In some embodiments, the interface may be a multi-port
interface providing both the negative-pressure connection and the
fluid supply connection as individual, fluidly isolated ports
within the multi-port interface, such as conduit 334. In such an
embodiment, a wall of one of the individual lumens, such as the
fluid withdrawal lumen 337 or the fluid supply lumen 338, may be
coupled to the filler material 340 or to the distribution hub 361
for fluidly isolating the fluid supply connection from the
negative-pressure connection. Other configurations for maintaining
the fluid isolation of the negative-pressure lumen 335 from the
fluid supply lumen 338 are possible.
[0123] FIG. 5 shows an exemplary embodiment in which fluid
instillation pathways 365 emanating from distribution hub 361
through fluid instillation tubes 358 and are separate from fluid
removal pathways 350 flowing into manifolding layer 148 through
fluid removal tubes and fluid removal hub 352. The configuration of
providing the instillation fluid and the associated back-pressure
along the fluid instillation pathways 365 through fluid
instillation tubes 358 and using the distribution hub 361 may
facilitate delivery of the instillation fluid to the tissue site
112 in a substantially uniform manner.
[0124] The treatment device 301 may be covered at the tissue site
112 with the cover 320 to provide a sealed space containing the
treatment device 301. The cover 320 may be positioned and fluidly
sealed about the tissue site 112 with the attachment device 332, as
described above. Apertures in the cover 320 may be cut or otherwise
disposed through the cover 320 as necessary, if not already
provided as part of the cover 320. In some embodiments,
instillation fluid may be independently fed from a fluid source,
such as fluid source 308, through the fluid supply lumen 338 and
into the chamber 380. Thus, in some embodiments such as shown in
FIG. 5, the instillation fluid may be fed directly to a fluid hub,
such as distribution hub 361, and therefore, the fluid instillation
pathways 365 and the fluid removal pathways 350 may be controlled
as separate entities. In these embodiments, potential contamination
of clean fluid instillation pathways may be reduced or largely
eliminated, and a more efficient cleansing cycle may be obtained.
In other embodiments such as shown in FIG. 4, the instillation
fluid may also be fed directly into a fluid hub and through fluid
distribution pathways, but a single hub and a single set of
pathways would function for both fluid instillation and fluid
removal. In those embodiments, fluid removal hub 352 in FIG. 4
would function to assist fluid removal under negative-pressure
conditions and to assist fluid instillation under conditions for
flowing fluid to tissue site 112; similarly, fluid removal pathways
350 in FIG. 4 would function in the arrow directions to assist
fluid removal under negative-pressure conditions and opposite from
the arrow directions to assist fluid instillation under conditions
for flowing fluid to tissue site 112. Depending on how the
components of the treatment device 301 are specifically configured,
in some embodiments such as shown in FIG. 5, fluid may be fed
through the fluid instillation tubes 358 directly into low points
of an abdomen, such as the paracolic gutters 315 and 317.
[0125] Activating the negative-pressure source 306 may provide
negative pressure to the negative-pressure lumen 335 of the conduit
334, to the manifolding layer 148 through the fluid withdrawal
lumen 337, and into chamber 355. The fluid source 308 may provide
instillation fluid to the chamber 380 through the fluid supply
lumen 338 (or to the chamber 355 through repurposed fluid removal
lumen 337, such as in FIG. 4), for example, by activing a pump or
positive-pressure source in the fluid source 308, or by operation
of gravitational or manual user forces acting on the instillation
fluid. Negative pressure and instillation fluid may be provided to
the treatment device 301 simultaneously, or cyclically, at
alternate times. Further, negative pressure and instillation fluid
may be applied to the treatment device 301 intermittently or
continuously.
[0126] When the negative-pressure source 306 is activated, the
fluid removal lumen 337 of the conduit 334 may distribute the
negative pressure to the manifolding layer 148 or optionally to the
fluid removal hub 352 in fluid communication therewith. Fluid from
the tissue site 112 may be drawn or extracted through the open ends
and removal pathway apertures into the fluid removal pathways 350.
Fluid may be moved through the fluid removal pathways 350 and
optionally into fluid removal hub 352, where the fluid may be drawn
into the fluid withdrawal lumen 337 of the conduit 334 and
ultimately the container 310.
[0127] In some embodiments, some portion of fluid extracted from
the tissue site 112 may be stored within the manifolding layer 148
of the treatment device 301 before being drawn into the fluid
withdrawal lumen 337. The capability to provide fluid storage and
permeability while under negative pressure may require the
manifolding layer 148, or other porous portion of the assembly or
of the dressing layer 110, to have a higher volume of fluid
capacity compared to that of the fluid delivery tubes 358 that may
be under positive pressure. Fluid being instilled or delivered to
the tissue site 112, for example through fluid delivery tubes 358,
may not be required to first pass through portions of the treatment
device 301, such as the manifolding layer 148, that may encompass a
larger volume. Such a configuration is shown in FIG. 5 and may
enhance the distribution and efficient use of the instillation
fluid. Following completion of negative-pressure and/or fluid
instillation therapy, a user may remove the treatment device 301 as
a largely intact structure, thus maintaining an ease of use of the
treatment device 301.
[0128] In some embodiments, the fluid delivery tubes 358 may
comprise polyurethane film or foam bags with perforations. For
example, the fluid delivery tubes 358 may be constructed using two
layers of polyurethane film of approximately 100 micrometers in
thickness that are edge-welded together. The fluid delivery tubes
358 may have open ends for targeted fluid delivery. In some
embodiments, within each of the fluid delivery tubes 358 and the
optional fluid removal hub 352 may be a central core adapted to
ensure that an open pathway is maintained and to aid a user with
handling during placement. For example, this central core may be an
open-cell foam, such as a reticulated polyurethane. Dimensions of
the central core material positioned within the fluid delivery
tubes 358 may vary; for example, the central core material may
range from around 2 mm to 10 mm in thickness by about 5 mm to 15 mm
in width. In some embodiments, the central core material may be
around 6 mm in thickness by 10 mm in width. The length of the
central core material may be varied based on overall sizing
considerations of the treatment device 301. Some embodiments may
include a central core material having a width that varies along
its length, which may allow for break points to provide user
customization and sizing. In some instances, the fluid delivery
tubes 358 may be adapted so that any instillation fluid remaining
within the fluid delivery tubes 358 following delivery of
instillation fluid by the fluid source 308 may be squeezed from the
fluid delivery tubes 358 when negative pressure is applied to the
treatment device 301, thus ensuring that substantially all
instillation fluid is emptied from the fluid delivery tubes 358 to
better regulate the volume of instillation fluid provided during
therapy cycles.
[0129] In some embodiments, fluid instillation may optionally
incorporate a layer of manifolding material or matrix, which may be
referred to as an optional instillation matrix. In FIG. 4, the
manifolding layer 148 may serve that purpose, when not being used
for fluid removal. In FIG. 5, the optional instillation matrix
could surround the fluid delivery tubes 358 emanating from
distribution hub 361 and be oriented between the second
liquid-impermeable layer 375 and the first liquid-impermeable layer
351 in chamber 380. If present, the optional instillation matrix
could help ensure that the fluid instillation pathway remains open
and not occluded or sealed when subjected to negative pressure.
Example materials for the optional instillation matrix may be
similar to those for the manifolding layer 148 and may include
foams, such as polyurethane foam, Libeltex TDL2, Libeltex TL4,
Baltex 3DXD spacer fabrics, Baltex 4DXD spacer fabrics, embossed
films, or some other formed structure.
[0130] In some additional methods for providing negative-pressure
therapy and fluid instillation to a tissue site, rather than an
automated or other form of mechanical instillation device, a
manually-controlled instillation vessel, such as a fluid bag,
bottle, or other vessel, may be incorporated. Thus, in some
embodiments, during a first stage of a therapy cycle, a
negative-pressure source may apply negative-pressure therapy to a
treatment device and tissue site, while a device such as a clamp,
valve, or other form of closure device may prevent fluid from being
communicated from the manually-controlled instillation vessel to
the treatment device and tissue site. In some embodiments, during a
subsequent stage of a therapy cycle, a user may open the clamp or
other form of closure device and may manually regulate the volume
of fluid being instilled. During this instillation phase, the
negative-pressure source may remain active, thus providing
immediate removal of the instilled fluid from the treatment device
and tissue site. Thus, there may be virtually no dwell time of the
fluid in the tissue site, according to some embodiments of the
method. The user may then re-clamp or otherwise close the closure
device, thus stopping the flow of instillation fluid from the
manually-controlled instillation vessel. The negative-pressure
source may then continue to remove excess or remaining instillation
fluid, as well as exudates, from the treatment device and tissue
site. In some other embodiments of the disclosed method, rather
than allowing the negative-pressure source to remain active while
the fluid is instilled from the manually-controlled instillation
vessel, the negative-pressure source may be paused, thus allowing
the instillation fluid to dwell in the tissue site for a prescribed
period of time. When appropriate, the user may close off the
manually-controlled instillation vessel from delivering
instillation fluid. Prior or subsequent to instillation being
stopped, negative-pressure therapy may be recommenced, during which
time any excess or remaining fluids may be removed from the
treatment device and tissue site. In some embodiments, the
negative-pressure source may remain active, while instillation
fluid may be periodically provided in various stages.
[0131] The systems, apparatuses, and methods described herein may
provide significant advantages. For example, some embodiments of
the treatment device 301 may provide a combined temporary abdominal
closure dressing system with fluid instillation capability through
an independent matrix of fluid delivery tubing, as well as
negative-pressure fluid removal pathways for removal of
contaminated fluid. Some embodiments may provide means for
irrigating and cleansing an abdominal cavity while supporting and
protecting the abdominal contents, as well as increasing
interstitial fluid flow, removing contaminated fluid, and
controlling and/or reducing edema. Additionally, as a result of the
various layers and components of the dressing 100 applying tension
and closing force to the abdominal contents, quicker primary fascia
closure of the abdominal cavity may be facilitated.
[0132] In some embodiments, the therapy system 300 may provide
means for irrigating all areas of an abdominal cavity, including
small bowel loops, gutters, retroperitoneal space, portions of the
lymphatic system, etc., all while the dressing system is in place,
advantageously reducing time required for patients and clinical
staff in the operating room. Various embodiments can offer
configurations of fluid pathways designed to maximize the exposure
of internal organs of abdominal tissue sites to fluid instillation
therapy. Other embodiments of instillation besides those shown are
additionally or alternatively possible. Some embodiments may also
allow for longer dressing application times without adhering to the
fascia of abdominal tissue sites. In some embodiments, repeatable
as well as reliable fluid instillation that may be provided
relatively evenly to various portions of a tissue site. In some
embodiments, fluid irrigation and cleansing may be relatively
consistent, advantageously leading to a reduction in mortality of
patients suffering from septic abdominal cavities. Fluid
instillation may be managed at a patient's bedside and may be
custom-tailored and adjusted on a case-by-case basis.
[0133] Use of the therapy system 300 may enable exudate and
infectious material to be drained from tissue sites, such as the
abdominal cavity, which can reduce the presence of contaminated
abdominal fluids to promote healing. Furthermore, the therapy
system 300 may provide separate instillation and negative-pressure
pathways to ensure that contaminated fluid is fully removed from
the tissue site 112. In some embodiments of the therapy system 300,
instillation fluid may not be recirculated back into the tissue
site, which can increase the clinical benefits of irrigating tissue
sites.
[0134] The design of the therapy system 300 or specific portions
thereof may also allow for user sizing and/or customization at the
time of application to a patient in the operating room. In some
embodiments, improved ease of use for dressing placement, sizing,
and removal may be provided by built-in sizing or placement visual
markings or indicators for guiding users. Some embodiments of the
disclosed dressing systems may also include various components,
such as the fluid instillation pathways and/or fluid removal
pathways already pre-attached to the structural dressing layers to
further streamline and simplify use. In some embodiments, not only
may improved fluid delivery and removal be enabled, as compared to
existing dressing systems, but increased ease of use may be
promoted.
[0135] In some embodiments, the therapy system 300, and
particularly one or more layers or portions of the dressing 100,
may optionally comprise one or more additional materials. Such
optional components may include, for example, active materials such
as preservatives, stabilizing agents, plasticizers, matrix
strengthening materials, dyestuffs, and combinations thereof.
[0136] Additionally or alternatively, the description includes one
or more of the following embodiments.
[0137] Embodiment 1. An apparatus for filling a wound, the
apparatus comprising: an array of at least four truncated
ellipsoids interconnected to define at least one fluid path through
the array; wherein the interconnected ellipsoids are comprised of a
polyolefin, a polyester, a polyamide, a polystyrene, a
polydiolefin, a polyacrylonitrile, a polysiloxane, or a copolymer
or combination thereof; and wherein each of the interconnected
ellipsoids has a surface hardness from about 0 Shore A to about 25
Shore A.
[0138] Embodiment 2. An apparatus for filling a wound, the
apparatus comprising: an array of interconnected polymeric ovules
having a truncated ellipsoidal shape, wherein: each set of four
interconnected ovules defines a fluid pathway extending
perpendicularly through the array; each truncated ellipsoidal shape
comprises an approximately elliptical contact surface at each
contact surface between two interconnected ovules; and each
interconnected polymeric ovule has its longest principal axis
oriented substantially perpendicular to the array.
[0139] Embodiment 3. An apparatus for filling a wound, the
apparatus comprising: a layer having a plurality of fluid pathways
through the layer from a first surface to a second surface,
wherein: an array of connected polymeric protrusions extends
through the layer connecting the first and second surfaces; each
set of four connected polymeric protrusions from each of the first
and second surfaces defines one fluid pathway extending
perpendicularly through the array; and each fluid pathway has four
continuously-curved concave sides and has a parallelogram-shaped
cross-section with continuously-curved concave edges.
[0140] Embodiment 4. The apparatus of embodiment 3, wherein the
polymeric protrusions have a shape of truncated ellipsoids,
optionally of truncated spheroids.
[0141] Embodiment 5. The apparatus of embodiment 1 or embodiment 4,
wherein each of the truncated ellipsoids, optionally the truncated
spheroids, has a principal axis oriented substantially
perpendicular to the array.
[0142] Embodiment 6. The apparatus of embodiment 4 of embodiment 5,
wherein the interconnected ellipsoids (or spheroids) are truncated
only at each surface where the ellipsoids (or spheroids) are
interconnected.
[0143] Embodiment 7. The apparatus of any of the previous
embodiments, wherein the array comprises: at least three columns
comprising two edge columns and at least one central column; and at
least three rows comprising two edge rows and at least one central
row, and wherein each set of four interconnected ovules or
truncated ellipsoids (or truncated spheroids) is arranged in two of
the at least three rows and two of the at least three columns.
[0144] Embodiment 8. The apparatus of embodiment 7, wherein the
array comprises four corner ovules, at least four edge ovules, at
least one central ovule, and at least four fluid pathways
interstitially therebetween, each central ovule having a truncated
ellipsoidal (or spheroidal) shape with four elliptical contact
surfaces, each edge ovule having a truncated ellipsoidal (or
spheroidal) shape with three elliptical contact surfaces, and each
corner ovule having a truncated ellipsoidal (or spheroidal) shape
with two elliptical contact surfaces.
[0145] Embodiment 9. The apparatus of any one of embodiments 2-8,
wherein the interconnected ovules are comprised of a polyolefin, a
polyester, a polyamide, a polystyrene, a polydiolefin, a
polyacrylonitrile, a polysiloxane, or a copolymer or combination
thereof.
[0146] Embodiment 10. The apparatus of any of the previous
embodiments, wherein each interconnected ovule or ellipsoid (or
spheroid) has its two principal axes other than the longest
principal axis, respectively, oriented at approximately a
45.degree. angle to a row direction of the array and at
approximately a 45.degree. angle to a column direction of the
array.
[0147] Embodiment 11. The apparatus of any one of the previous
embodiments, wherein the array of interconnected ellipsoids (or
spheroids) or interconnected ovules has an upper surface and a
lower surface, and wherein the upper surface or the lower surface
or both has a hardness from about 0 Shore A to about 25 Shore
A.
[0148] Embodiment 12. The apparatus of embodiment 11, wherein: the
upper surface or the lower surface or both has a coating disposed
thereon that exhibits a hardness of at least 55 Shore A; the
coating is comprised of a cellulosic material, a polyester, a
polyamide, a polycarbonate, a perhalogenated polyolefin, an aramid,
a polybenzimidazole, a polysulfone, or a copolymer, combination, or
cross-linked gel thereof; or both.
[0149] Embodiment 13. The apparatus of any of the previous
embodiments, wherein at least a portion of the interconnected
ellipsoids (or spheroids) or at least a portion of the
interconnected ovules comprise one or more grooves on an outer
surface of each ellipsoid (or spheroid) or of each ovule that
extend at least partially in a direction of its longest principal
axis.
[0150] Embodiment 14. The apparatus of embodiment 13, wherein each
groove has an average depth no more than 30% of a diameter of each
interconnected ovule or of each interconnected ellipsoid (or
spheroid) along a principal axis direction other than the longest
principal axis.
[0151] Embodiment 15. The apparatus of any of the previous
embodiments, wherein a longest principal axis of each
interconnected ellipsoid (or spheroid) or each interconnected ovule
is from about 3 mm to about 6 mm or is from about 2 mm to about 4
mm.
[0152] Embodiment 16. The apparatus of any of the previous
embodiments, wherein each fluid pathway has a minimum width
dimension from about 500 microns to about 1500 microns.
[0153] Embodiment 17. The apparatus of any of the previous
embodiments, wherein the apparatus is translucent.
[0154] Embodiment 18. The apparatus of any of the previous
embodiments, further comprising a wound healing agent in or on the
array, the wound healing agent comprising a non-steroidal
anti-inflammatory drug, a steroid, an anti-inflammatory cytokine,
an anaesthetic, an antiseptic, an antimicrobial agent, a growth
factor, a peptide, a microRNA, an antioxidant, or a combination
thereof, optionally wherein the antimicrobial agent comprises
silver, a silver salt, a tetracycline, a beta-lactam, a macrolide,
an aminoglycoside, a fluoroquinolone, a cellulose ethyl sulfonate,
or a combination thereof.
[0155] Embodiment 19. A dressing for treating a tissue site, the
dressing comprising: an apparatus according to any of the previous
embodiments; a dressing layer coupled to the apparatus; a backing
layer disposed over a surface of the dressing layer opposite from
the apparatus; and an attachment device disposed on at least a
margin of the backing layer.
[0156] Embodiment 20. The dressing of embodiment 19, wherein the
attachment device is configured to form a seal with a tissue site,
and wherein the dressing layer is coupled to the apparatus on a
surface opposite the protrusions, or on a surface formed by
truncation of the ovules or of the ellipsoids on one end of a
principal axis oriented substantially perpendicular to the
array.
[0157] Embodiment 21. The dressing of embodiment 19 or embodiment
20, wherein the dressing layer comprises an absorbent layer
containing from about 45% to about 90% carboxymethyl cellulose
fibers and from about 10% to about 55% reinforcing fibers.
[0158] Embodiment 22. The dressing of any of embodiments 19-21,
wherein the dressing layer comprises a manifolding layer configured
to allow both fluid removal and fluid instillation
therethrough.
[0159] Embodiment 23. A system for treating a tissue site with
negative pressure, the system comprising: an apparatus according to
any of embodiments 1-18 or a dressing according to any of
embodiments 19-22; a negative-pressure source fluidly coupled to
the dressing and configured to enable fluid removal through the
dressing; optionally a negative-pressure conduit; optionally a
negative-pressure connector subsystem for fluidly coupling the
negative-pressure source to the apparatus or the dressing for fluid
removal; and optionally a container fluidly coupled to the
negative-pressure source and to the apparatus or to the dressing
and adapted to collect fluid.
[0160] Embodiment 24. A method for treating a compartmented wound
site, for example comprising a peritoneal or abdominal cavity, the
method comprising: deploying within a compartmented wound site the
apparatus of any of embodiments 1-18 or a dressing according to any
of embodiments 19-22, or at least a portion of the system for
treating a tissue site according to embodiment 23; deploying a
negative-pressure connector subsystem; deploying a sealing member
to form a fluid seal over the open cavity; fluidly coupling the
negative-pressure connector subsystem to a negative-pressure
source; and activating the negative-pressure source.
[0161] Embodiment 25. A method for treating a surface wound site,
for example comprising a burn, a graft, an overhang wound, a
contusion, or a post-operative wound, the method comprising:
deploying over the surface wound site the apparatus of any of
embodiments 1-18 or a dressing according to any of embodiments
19-22, or at least a portion of the system for treating a tissue
site according to embodiment 23; deploying a negative-pressure
connector subsystem; deploying a sealing member to form a fluid
seal over the surface wound site; fluidly coupling the
negative-pressure connector subsystem to a negative-pressure
source; and activating the negative-pressure source.
[0162] Embodiment 26. A method for treating a tunnel wound site,
for example comprising a puncture or a fistula, the method
comprising: deploying within the tunnel wound site the apparatus of
any of embodiments 1-18 or a dressing according to any of
embodiments 19-22, or at least a portion of the system for treating
a tissue site according to embodiment 23, the dressing substrate
comprising a cylinder or tube; deploying a negative-pressure
connector subsystem; deploying a sealing member to form a fluid
seal over the tunnel wound; fluidly coupling the negative-pressure
connector subsystem to a negative-pressure source; and activating
the negative-pressure source.
[0163] Embodiment 27. A method of reducing edema and/or increasing
interstitial fluid flow for a tissue site, the method comprising
positioning the apparatus of any of embodiments 1-18 or a dressing
according to any of embodiments 19-22, or at least a portion of the
system for treating a tissue site according to embodiment 23 over
the tissue site.
EXAMPLES
[0164] One, some, or all of the advantages associated with the
disclosed compositions, dressings, methods of making, and methods
of using or treating may be further demonstrated by the following
non-limiting examples.
Example 1
[0165] In this Example, a non-GLP histopathological study was
conducted to evaluate performance in full-thickness skin excisional
wounds in porcine animals using wound filler materials with
negative-pressure wound therapy (NPWT). Each full-thickness skin
excisional wound was approximately 3 cm.times.7.5 cm, with each
sample wound filler material being approximately the same size as
each wound. Each sample wound filler material was placed within its
respective full-thickness skin excisional wound, topped with a
polyurethane drape to form a dressing, and used in conjunction with
a T.R.A.C..TM. Pad negative-pressure interface to enable V.A.C..TM.
Therapy (available from KCI of San Antonio, Tex.). Each wound was
treated in this way for about a six (6) day testing period, with en
bloc wound sites, including adequate surrounding tissue, being
excised for histopathological evaluation. After excision, each
wound site was affixed to a substrate and submerged in 10% neutral
buffered formalin (NBF) for about 72 hours, after which affixed
wound sites were transferred to alcohol (70% ethanol) until being
removed for analysis. After removal, wound sites were trimmed,
processed, embedded in paraffin, sliced in cross-section
(approximately 5 microns thick), and stained with hematoxylin and
eosin (H&E) for contrast. Two protocols were conducted for each
wound: Group 1 wounds included a dressing change at the midpoint of
the experiment (Day 3), such that each fresh dressing was only in
contact with its respective wound site for 3 days; and Group 2
wounds had the original dressing maintained for the entire 6
days.
[0166] Sample 1 corresponded to a wound filler material according
to FIGS. 1A-1E and having top and bottom surfaces each with a Shore
A hardness of approximately 0. Sample 2 corresponded to a wound
filler material according to FIGS. 1A-1E and having top and bottom
surfaces each with a Shore A hardness of approximately 7.
Comparative Sample 3 corresponded to a GranuFoam.TM. wound filler
material (available from KCI of San Antonio, Tex.). Comparative
Sample 4 corresponded to a standard gauze wound filler
material.
[0167] Total wound site granulation and tissue ingrowth were probed
for each sample. Wound site granulation was evaluated
quantitatively for each excised wound site using ImagePro Plus.TM.
software. Granulation tissue limits of both underlying granulation
tissue filling each wound bed and (granulation) tissue ingrowth
into each wound filler/dressing material were marked digitally on
images of each wound bed cross-section. Wound section granulation
tissue thickness measurements were made approximately 2 mm from the
left edge of each wound and were repeated approximately every 2 mm
until the last measurement approximately 2 mm from the right edge
of each wound. Measurements were made approximately perpendicular
to the contour of the tissue underlying each wound. Where
granulation tissue at a measurement point was not continuous for
its full depth (for example, where interrupted by seroma or other
non-granulation tissue feature), individual measurements were taken
and added to calculate a sum representing the underlying
granulation tissue thickness. Total granulation tissue thickness
represented the sum of the underlying granulation tissue thickness
and the tissue ingrowth thickness. Underlying granulation tissue
was also evaluated semi-quantitatively, according to the following
scoring scale: 0=no observable granulation filling a wound bed;
1=.about.1% to .about.25% of a wound bed is filled with granulation
tissue; 2=.about.26% to .about.50% of a wound bed is filled with
granulation tissue; 3=.about.51% to .about.75% of a wound bed is
filled with granulation tissue; 4=.about.76% to 100% of a wound bed
is filled with granulation tissue; and 5=more than 100% of a wound
bed is filled with granulation tissue (excessive granulation
tissue). Amount of granulation tissue ingrowth into each wound
filler/dressing material was also evaluated semi-quantitatively,
according to the following scoring scale: 0=absent; 1=minimal;
2=mild' 3=moderate; 4=marked; and 5=severe. The results are shown
in Table 1 below.
[0168] It can be seen from the tabulated results, both
quantitatively and in semi-quantitative scoring, that wound filler
Samples 1 and 2 exhibited slightly lower mean total granulation
tissue thickness, and notably also lower mean tissue ingrowth
thickness, in both experimental groups of negative-pressure wound
treatments than Comparative wound filler Samples 1 and 2.
Importantly, the most significant difference can be seen in the
mean tissue ingrowth thickness in Group 1 NPWT tests, where
semi-quantitative scoring showed a statistically significant
reduction in tissue ingrowth scores for Samples 1 and 2, relative
to Comparative Samples 3 and 4, and where quantitative mean tissue
ingrowth thicknesses are on the edge of statistical significance.
Furthermore, the ratio of tissue ingrowth to wound bed granulation
tissue is desirably low for Samples 1 and 2, as it can be highly
desirable to reduce tissue ingrowth while simultaneously promoting
wound bed granulation, which implies wound healing. For Samples 1
and 2, slight increase in mean tissue ingrowth thicknesses and
scores while maintaining similar mean total granulation tissue
thicknesses in Group 2 NPWT tests, as well as an increased ratio of
tissue ingrowth to wound bed granulation tissue in Group 2 NPWT
tests. These results appear to imply that, for wound filler Samples
1 and 2 under NPWT therapy, granulation was stimulated in the wound
bed on the relatively short time scale of 3 days or less and that
little if any additional granulation was stimulated on the
subsequent time scale of 3 additional days. Additionally, these
results appear to imply that, for wound filler Samples 1 and 2
under NPWT therapy, wound bed granulation likely did not reduce
between 3 days and 6 days but more likely wound bed granulation
appeared to turn into tissue ingrowth. This latter observation
would appear to indicate that, for apparatuses or dressings
according to FIGS. 1A-1E, an advantageous combination of
significant healing wound bed granulation and significantly little
or no tissue ingrowth can be attained by NPWT therapy involving
periodic dressing changes and that such an advantage can recede
with increased time between dressing changes. The biological or
physico-chemical reasons behind these histopathological
observations and implications are not currently clear, and there
can be varying theories which are not presented here.
TABLE-US-00001 TABLE 1 Mean total Granulation Mean underlying
granulation tissue filling granulation Mean tissue Granulation
Label tissue thickness wound tissue thickness ingrowth thickness
tissue ingrowth (Test) (mm) score (mm) (mm) score Sample 0.9 .+-.
1.0 1.5 .+-. 0.7 0.8 .+-. 0.8 0.1 .+-. 0.1 0.5 .+-. 0.7 1 (Grp 1)
Sample 1.1 .+-. 0.6 1.5 .+-. 0.7 0.7 .+-. 0.6 0.4 .+-. 0.0 1.0 .+-.
0.0 2 (Grp 1) Comparative 1.5 .+-. 0.4 2.0 .+-. 0.0 0.7 .+-. 0.1
0.8 .+-. 0.4 2.0 .+-. 0.0 Sample 3 (Grp 1) Comparative 2.7 .+-. 1.3
3.0 .+-. 0.0 2.1 .+-. 0.9 0.7 .+-. 0.4 2.0 .+-. 0.0 Sample 4 (Grp
1) Sample 0.7 .+-. 0.5 1.3 .+-. 0.5 0.4 .+-. 0.4 0.3 .+-. 0.2 1.0
.+-. 0.0 1 (Grp 2) Sample 1.5 .+-. 2.1 1.3 .+-. 0.5 1.4 .+-. 2.2
0.2 .+-. 0.2 0.5 .+-. 0.6 2 (Grp 2) Comparative 1.6 .+-. 0.7 1.7
.+-. 0.6 0.9 .+-. 0.6 0.6 .+-. 0.3 1.7 .+-. 0.6 Sample 3 (Grp 2)
Comparative 1.7 .+-. 0.4 2.0 .+-. 0.0 1.0 .+-. 0.2 0.6 .+-. 0.3 2.0
.+-. 0.0 Sample 4 (Grp 2)
[0169] Although not specifically tabulated herein, peel test
studies were done on both Samples 1 and 2 and Comparative Samples 3
and 4 to probe ease of removal from each wound site at each
dressing change. No significant difference was observed between
peel tests at 3 days and at 6 days for Samples 1 and 2, and no
significant difference was observed between peel tests for wounds
filled by Samples 1 or 2 and wounds filled by Comparative Samples 3
or 4.
[0170] Non-Limiting Discussion of Terminology
[0171] While shown in a few illustrative embodiments and examples,
a person having ordinary skill in the art will recognize that the
systems, apparatuses, and methods described herein are susceptible
to various changes and modifications and are not intended to limit
the scope of the claimed subject matter. Moreover, recitation of
multiple embodiments having stated features does not exclude other
embodiments having additional features, or other embodiments
incorporating different combinations of the stated features.
Components may also be combined or eliminated in various
configurations for purposes of sale, manufacture, assembly, or use.
For example, in some configurations the treatment device 301
including the dressing 100, the container 310, or both may be
eliminated or separated from other components for manufacture or
sale. In other example configurations, the controller 309 may
additionally or alternatively be manufactured, configured,
assembled, or sold independently of other components. Specific
examples are provided for illustrating how to make and use the
compositions, and examples of methods are not intended to be a
representation that given embodiments have, or have not, been made
or tested. Equivalent changes, modifications and variations of some
embodiments, materials, compositions and methods can be made within
the scope of the appended claims, with substantially similar
results.
[0172] As used herein, the words "include," "contain," and their
variants, are intended to be non-limiting, such that recitation of
items in a list is not necessarily to the exclusion of other like
items that may also be useful in the materials, compositions,
devices, and methods of this technology. Similarly, the terms "can"
and "may" and their variants are intended to be non-limiting, such
that recitation that an embodiment can or may comprise certain
elements or features does not exclude other embodiments that do not
contain those elements or features. Moreover, descriptions of
various alternatives using terms such as "or" do not require mutual
exclusivity unless clearly required by the context, and the
indefinite articles "a" or "an" do not limit the subject to a
single instance unless clearly required by the context.
[0173] Although the open-ended term "comprising," as a synonym of
non-restrictive terms such as including, containing, or having, is
used herein to describe example embodiments, embodiments may
alternatively be described using more limiting terms such as
"consisting of" or "consisting essentially of" Thus, for any given
embodiment reciting materials, components or process steps with
such open-ended terms, similar or analogous embodiments are
contemplated consisting of, or consisting essentially of, such
materials, components or processes excluding additional materials,
components or processes (for consisting of) and excluding
additional materials, components or processes affecting the
significant properties of the embodiment (for consisting
essentially of), even though such additional materials, components
or processes are not explicitly recited in this application. For
example, recitation of a composition or process reciting elements
A, B and C specifically envisions embodiments consisting of, and
consisting essentially of, A, B and C, excluding an element D that
may be recited in the art, even though element D is not explicitly
described as being excluded herein.
[0174] Disclosure of values and ranges of values for specific
parameters, such as temperatures, molecular weights, weight
percentages, etc., are not exclusive of other values and ranges of
values useful herein. It is envisioned that two or more specific
exemplified values for a given parameter may define endpoints for a
range of values that may be claimed for the parameter. For example,
if Parameter X is exemplified herein to have value A and also
exemplified to have value Z, it is envisioned that parameter X may
have a range of values from about A to about Z. Similarly,
disclosure of two or more ranges of values for a parameter, whether
such ranges are nested, overlapping or distinct, may subsume all
possible combination of ranges for the value that might be claimed
using endpoints of the disclosed ranges. For example, if parameter
X is exemplified herein to have values in the range of 1-10, or
2-9, or 3-8, Parameter X may be envisioned as having other ranges
of values including 1-2, 1-3, 1-8, 1-9, 2-3, 2-8, 2-10, 3-9, 3-10,
8-9, 8-10, and 9-10.
[0175] The term "about," as used herein, is intended to refer to
deviations in a numerical quantity that may result from various
circumstances, for example, through measuring or handling
procedures in the real world; through inadvertent error in such
procedures; through differences in the manufacture, source, or
purity of compositions or reagents; from computational or rounding
procedures; and other deviations as will be apparent by those of
skill in the art from the context of this disclosure. For example,
unless otherwise defined by the specification per se or by the
context of the specification, the term "about," with reference to a
value, may refer to any number that would round to that value,
based on a significant digit analysis. In such a circumstance, a
value of "about 30%", assuming the "3" is the only significant
digit, could encompass from 25% to just below 35%. However, the
context of the specification would limit that interpretation based
on significant digits, so that the "about" ranges do not overlap.
For example, if the specification discloses ranges that include
"about 25%, about 30%, about 35%," etc., about 30% in that context
could encompass from 27.5% to just below 32.5%. Alternatively, the
term "about" may refer to deviations that are greater or lesser
than a stated value or range by .+-.10% of the stated value(s), as
appropriate from the context of the disclosure. In such a
circumstance, a value of "about 30%" may encompass from 27% to 33%.
Whether or not modified by the term "about," quantitative values
recited herein include equivalents to the recited values, for
example, deviations from the numerical quantity, as would be
recognized as equivalent by a person skilled in the art in view of
this disclosure.
[0176] The appended claims set forth novel and inventive aspects of
the subject matter disclosed and described above, but the claims
may also encompass additional subject matter not specifically
recited in detail. For example, certain features, elements, or
aspects may be omitted from the disclosure and claims, if not
necessary to distinguish the novel and inventive features from what
is already known to a person having ordinary skill in the art.
Features, elements, and aspects described herein may also be
combined or replaced by alternative features serving the same,
equivalent, or similar purpose without departing from the scope of
the invention, as defined by the appended claims.
* * * * *