U.S. patent application number 16/106324 was filed with the patent office on 2018-12-13 for protease modulating wound interface layer for use with negative pressure wound therapy.
The applicant listed for this patent is KCI Licensing, Inc.. Invention is credited to Breda Mary Cullen, Christopher Brian Locke, Timothy Mark Robinson.
Application Number | 20180353639 16/106324 |
Document ID | / |
Family ID | 54011886 |
Filed Date | 2018-12-13 |
United States Patent
Application |
20180353639 |
Kind Code |
A1 |
Locke; Christopher Brian ;
et al. |
December 13, 2018 |
Protease Modulating Wound Interface Layer For Use With Negative
Pressure Wound Therapy
Abstract
Systems, methods, and apparatuses for modulating proteases
including matrix metalloproteinase (MMP), elastase, and bacterial
protease in a negative pressure therapy system are described. A
mesh having a sacrificial substrate is included. The sacrificial
substrate includes a plurality of collagen fibers reinforced with a
supporting material and intersecting with each other to form a
network of collagen fibers having a plurality openings. The
openings of the plurality of openings have an average area between
about 0.5 mm.sup.2 and about 20 mm.sup.2 to permit the flow of
negative pressure through the mesh. The sacrificial substrate can
also include oxidized regenerated cellulose.
Inventors: |
Locke; Christopher Brian;
(Bournemouth, GB) ; Robinson; Timothy Mark;
(Shillingstone, GB) ; Cullen; Breda Mary;
(Skipton, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KCI Licensing, Inc. |
San Antonio |
TX |
US |
|
|
Family ID: |
54011886 |
Appl. No.: |
16/106324 |
Filed: |
August 21, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14819988 |
Aug 6, 2015 |
10076587 |
|
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16106324 |
|
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62035880 |
Aug 11, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61L 15/325 20130101;
A61L 15/28 20130101; A61H 9/0057 20130101; A61L 15/425 20130101;
A61L 15/42 20130101; A61L 2430/34 20130101; A61L 15/225
20130101 |
International
Class: |
A61L 15/42 20060101
A61L015/42; A61L 15/32 20060101 A61L015/32; A61H 9/00 20060101
A61H009/00; A61L 15/28 20060101 A61L015/28; A61L 15/22 20060101
A61L015/22 |
Claims
1.-101. (canceled)
102. A mesh for modulating proteases, comprising: a first plurality
of fibers comprising collagen; and a second plurality of fibers
comprising oxidized regenerated cellulose; wherein at least a
portion of the first plurality of fibers are positioned to
intersect at least a portion of the second plurality of fibers.
103. The mesh of claim 102, wherein at least a portion of the first
plurality of fibers and at least a portion of the second plurality
of fibers are woven.
104. The mesh of claim 102, wherein the first plurality of fibers
and the second plurality of fibers are positioned in an alternating
arrangement.
105. The mesh of claim 102, wherein each of the second plurality of
fibers comprises a supporting material and oxidized regenerated
cellulose.
106. The mesh of claim 105, wherein: the supporting material is
formed into fibers; and the oxidized regenerated cellulose is in
the form of a powder dispersed on the fibers formed from the
supporting material.
107. The mesh of claim 102, wherein each of the second plurality of
fibers has a diameter of no greater than 1 mm.
108. The mesh of claim 102, wherein each of the second plurality of
fibers comprises a plurality of filaments.
109. The mesh of claim 102, wherein the second plurality of fibers
forms between 30% and 70% of the mesh.
110. The mesh of claim 102, further comprising a plurality of
openings positioned between the first plurality of fibers and the
second plurality of fibers.
111. The mesh of claim 110, wherein the plurality of openings have
an average area of between 0.2 mm.sup.2 and 20 mm.sup.2 to permit
the flow of negative pressure through the mesh.
112. The mesh of claim 110, wherein the openings are generally
circular in shape and have an average diameter between 0.5 mm and
5.0 mm.
113. The mesh of claim 110, wherein the openings are generally
circular in shape and have an average diameter between 1 mm and 2.5
mm.
114. The mesh of claim 102, wherein the mesh has a thickness of
between 5 microns and 2 millimeters.
115. A mesh for modulating proteases in a negative pressure therapy
system, comprising: a plurality of collagen fibers; and a
supporting material adapted to provide structural support to the
mesh; wherein the mesh comprises a plurality of openings positioned
between the plurality of collagen fibers and the supporting
material, wherein the plurality of openings have an average area
between about 0.2 mm.sup.2 and about 20 mm.sup.2 to permit the flow
of negative pressure through the mesh.
116. The mesh of claim 115, wherein at least a portion of the
supporting material is disposed within the plurality of collagen
fibers.
117. The mesh of claim 115, wherein the openings are generally
circular in shape and have an average diameter between 1 mm and 2.5
mm.
118. The mesh of claim 115, wherein the plurality of collagen
fibers have a diameter of less than 1 millimeter.
119. The mesh of claim 115, wherein the collagen fibers have a
collagen content between about 10% and about 50% of the total
material of the collagen fiber.
120. The mesh of claim 115, wherein the supporting material
comprises supporting fibers.
121. The mesh of claim 120, wherein the supporting fibers are
twisted with the plurality of collagen fibers.
122. The mesh of claim 120, wherein at least a portion of the
supporting fibers and at least a portion of the plurality of
collagen fibers are woven together.
123. The mesh of claim 120, wherein the supporting fibers are water
soluble.
124. The mesh of claim 120, wherein the supporting fibers are
biodegradable.
125. The mesh of claim 120, wherein the collagen fibers and
supporting fibers are non-woven.
126. The mesh of claim 115, wherein the collagen fibers comprise:
staple fibers formed from collagen; and staple fibers formed from
the supporting material and twisted together with the staple fibers
formed of collagen.
127. The mesh of claim 126, wherein the supporting material
comprises one or more selected from a group consisting of:
polyethylene oxide, alginate, polylactic acid, polyvinyl alcohol,
polycaprolactones, and polyamides.
128. The mesh of claim 126, wherein a length of the staple fibers
formed from collagen is between about 4 mm and about 6 mm.
129. The mesh of claim 115, further comprising a plurality of
oxidized regenerated cellulose fibers intersecting the collagen
fibers.
130. A negative-pressure system for modulating proteases in a
tissue site, comprising: a modulating layer comprising a plurality
of collagen fibers and a supporting material adapted to provide
structural support to the modulating layer, wherein the modulating
layer comprises a plurality of openings between the plurality of
collagen fibers; a manifold configured to be positioned adjacent
the modulating layer; and a cover configured to be positioned over
the manifold and the modulating layer to form a sealed space around
the tissue site.
131. The system of claim 130, further comprising a
negative-pressure interface adapted to be fluidly coupled to the
manifold through the cover.
132. The system of claim 130, further comprising a
negative-pressure source configured to be fluidly coupled to the
manifold to provide negative pressure to the sealed space.
133. The system of claim 130, wherein the openings of the plurality
of openings have an average effective diameter between 0.5 mm and 5
mm to permit the flow of negative pressure through the modulating
layer.
134. The system of claim 130, wherein the openings are generally
circular in shape and have an average diameter between about 1 mm
and about 2.5 mm.
135. The system of claim 130, wherein the collagen fibers have a
diameter of less than about 1 millimeter.
136. The system of claim 130, wherein the supporting material
comprises supporting fibers.
137. The system of claim 136, wherein at least a portion of the
supporting fibers are twisted with at least a portion of the
plurality of collagen fibers.
138. The system of claim 136, wherein at least a portion of the
plurality of supporting fibers and at least a portion of the
plurality of collagen fibers are woven together.
139. The system of claim 140, wherein the collagen fibers and
supporting fibers are non-woven.
140. The system of claim 130, wherein the modulating layer further
comprises a plurality of oxidized regenerated cellulose fibers
intersecting the collagen fibers.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 14/819,988, entitled "Protease Modulating Wound Interface Layer
for Use With Negative Pressure Wound Therapy," filed Aug. 6, 2015,
which claims the priority benefit, under 35 USC .sctn. 119(e), of
the filing of U.S. Provisional Patent Application No. 62/035,880,
entitled "Protease Modulating Wound Interface Layer for use with
Negative Pressure Wound Therapy," filed Aug. 11, 2014, all of which
are incorporated herein by reference for all purposes.
TECHNICAL FIELD
[0002] The invention set forth in the appended claims relates
generally to tissue treatment systems and more particularly, but
without limitation, to a wound interface layer that modulates
matrix metalloproteinase in a tissue site.
BACKGROUND
[0003] Clinical studies and practice have 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 negative pressure may be commonly referred to as
"negative-pressure therapy," but is also known by other names,
including "negative-pressure wound therapy," "negative-pressure
therapy," "vacuum therapy," and "vacuum-assisted closure," for
example. Negative-pressure therapy may provide a number of
benefits, including migration of epithelial and subcutaneous
tissues, improved blood flow, and micro-deformation of tissue at a
wound site. Together, these benefits can increase development of
granulation tissue and reduce healing times.
[0004] While the clinical benefits of negative-pressure therapy are
widely known, the cost and complexity of negative-pressure therapy
can be a limiting factor in its application, and the development
and operation of negative-pressure systems, components, and
processes continues to present significant challenges to
manufacturers, healthcare providers, and patients.
BRIEF SUMMARY
[0005] New and useful systems, apparatuses, and methods for
modulating matrix metalloproteinase (MMPs) in a negative-pressure
therapy environment are set forth 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. For
example, a mesh for modulating matrix metalloproteinase (MMP) in a
negative pressure therapy system is described. The mesh may include
a sacrificial substrate including a plurality of collagen fibers
reinforced with a supporting material and intersecting with each
other to form a network of collagen fibers having a plurality
openings. The openings of the plurality of openings have an average
area between about 0.2 mm.sup.2 and about 20 mm.sup.2 to permit the
flow of negative pressure through the mesh.
[0006] Alternatively, other example embodiments describe a
negative-pressure therapy system for modulating matrix
metalloproteinase (MMP) in a tissue site. The system includes a
modulating layer including a plurality of collagen fibers
reinforced with a supporting material and intersecting with each
other to form a network of collagen fibers having a plurality
openings. The openings of the plurality of openings have an average
area between about 0.2 mm.sup.2 and about 20 mm.sup.2 to permit the
flow of negative pressure through the mesh. The system may also
include a manifold configured to be positioned adjacent the network
and a cover configured to be positioned over the manifold and the
network and coupled to tissue adjacent the tissue site to form a
sealed space. A negative-pressure source may be configured to be
fluidly coupled to the manifold to provide negative pressure to the
sealed space through the manifold and the network.
[0007] In other embodiments, a method for manufacturing an
apparatus for modulating matrix metalloproteinase (MMP) in a tissue
site in a negative-pressure therapy environment is described. A
plurality of collagen fibers reinforced with a supporting material
may be formed, and a sacrificial substrate having the plurality of
collagen fibers may be formed from the collagen fibers. The
plurality of collagen fibers may be coupled to each other at
intersections with each other to form a network of collagen fibers
having a plurality openings. The openings of the plurality of
openings have an average area between about 0.2 mm.sup.2 and about
20 mm.sup.2 to permit the flow of negative pressure through the
mesh.
[0008] In still further embodiments, a method for providing
negative-pressure therapy and modulating matrix metalloproteinase
(MMP) in a tissue site is described. A sacrificial network may be
provided that includes a plurality of collagen fibers reinforced
with a supporting material and intersecting with each other to form
a plurality openings. The openings of the plurality of openings
have an average area between about 0.2 mm.sup.2 and about 20
mm.sup.2 to permit the flow of negative pressure through the mesh.
The sacrificial network may be positioned adjacent to the tissue
site, and a manifold may be positioned adjacent to the sacrificial
network. A negative-pressure source may be fluidly coupled to the
manifold, and negative pressure may be provided to the tissue site
through the manifold and the sacrificial network.
[0009] 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
[0010] FIG. 1 is a sectional view, with a portion show in elevation
of an example embodiment of a negative-pressure therapy system that
can modulate matrix metalloproteinase in accordance with this
specification;
[0011] FIG. 2 is a perspective view, illustrating additional
details that may be associated with a mesh of the negative-pressure
therapy system of FIG. 1;
[0012] FIG. 3 is a perspective view, illustrating additional
details that may be associated with another mesh of the
negative-pressure therapy system of FIG. 1;
[0013] FIG. 4 is a schematic view, illustrating additional details
that may be associated with another mesh of the negative-pressure
therapy system of FIG. 1; and
[0014] FIG. 5 is a perspective view, illustrating additional
details that may be associated with another mesh of the
negative-pressure therapy system of FIG. 1.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0015] The following description of 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.
[0016] The 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.
[0017] FIG. 1 is sectional view, with a portion shown in elevation,
of a negative-pressure therapy system 100 that can provide
modulating agents to matrix metalloproteinase (MMP) at a tissue
site 101 in accordance with this specification. The
negative-pressure therapy system 100 may include a dressing and a
negative-pressure source. For example, a dressing 102 may be
fluidly coupled to a negative-pressure source 104, as illustrated
in FIG. 1. A dressing may generally include a cover and a tissue
interface. The dressing 102, for example, includes a cover 106 and
a tissue interface 108. In some embodiments, the tissue interface
108 may include a manifold 112 and a mesh 114 that includes a
plurality of collagen fibers 126. The negative-pressure therapy
system 100 may also include a fluid container, such as a container
110, coupled to the dressing 102 and to the negative-pressure
source 104.
[0018] In general, components of the negative-pressure therapy
system 100 may be coupled directly or indirectly. For example, the
negative-pressure source 104 may be directly coupled to the
container 110 and indirectly coupled to the dressing 102 through
the container 110. Components may be fluidly coupled to each other
to provide a path for transferring fluids (i.e., liquid and/or gas)
between the components.
[0019] In some embodiments, for example, components may be fluidly
coupled through a tube, such as a tube 116, for example. A "tube,"
as used herein, broadly refers to 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 additionally or
alternatively be coupled by virtue of physical proximity, being
integral to a single structure, or being formed from the same piece
of material. Coupling may also include mechanical, thermal,
electrical, or chemical coupling (such as a chemical bond) in some
contexts.
[0020] The dressing 102 may be fluidly coupled to the container 110
through the tube 116 and a connector, such as a connector 118. For
example, the connector 118 may be a T.R.A.C..RTM. Pad or Sensa
T.R.A.C..RTM. Pad available from KCI of San Antonio, Tex. In some
embodiments, the connector 118 may be a portion of the tube 116
extending into a sealed therapeutic environment or may be a vacuum
port on a micro-pump that extends into the sealed therapeutic
environment.
[0021] In operation, the tissue interface 108 may be placed within,
over, on, adjacent, or otherwise proximate to a tissue site. The
cover 106 may be placed over the tissue interface 108 and sealed to
tissue near the tissue site 101. For example, the cover 106 may be
sealed to undamaged epidermis peripheral to the tissue site 101.
Thus, the dressing 102 can provide a sealed therapeutic environment
120 proximate to the tissue site 101, substantially isolated from
the external environment, and the negative-pressure source 104 can
reduce the pressure in the sealed therapeutic environment 120.
Negative pressure applied across the tissue site 101 through the
tissue interface 108 in the sealed therapeutic environment 120 can
induce macrostrain and microstrain in the tissue site 101, as well
as remove exudates and other fluids from the tissue site 101, which
can be collected in the container 110 and disposed of properly.
[0022] 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 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.
[0023] In general, exudates and other fluids flow toward lower
pressure along a fluid path. Thus, the term "downstream" typically
refers to a position in a fluid path relatively closer to a
negative-pressure source. Conversely, the term "upstream" refers to
a position relatively further away from a negative-pressure source.
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 of negative-pressure therapy
systems 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.
[0024] The term "tissue site" in this context broadly refers to a
wound or defect 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. The term "tissue site" may
also refer to areas of any tissue that are not necessarily wounded
or defective, 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 used in certain tissue areas to grow
additional tissue that may be harvested and transplanted to another
tissue location.
[0025] "Negative pressure" generally refers to a pressure less than
a local ambient pressure. An ambient pressure may be the pressure
in a local environment external to the sealed therapeutic
environment 120 provided by the dressing 102. In many cases, the
local ambient pressure may also be the atmospheric pressure at
which a tissue site is located. Alternatively, negative pressure
may be a pressure that is less than a hydrostatic pressure
associated with tissue at the tissue site 101. 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.
[0026] A negative-pressure source, such as the negative-pressure
source 104, 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 source 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 negative-pressure therapy. 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 -75 mm Hg (-9.9 kPa) and -300 mm Hg (-39.9 kPa).
[0027] The tissue interface 108 can be generally adapted to contact
the tissue site 101. The tissue interface 108 may be partially or
fully in contact with the tissue site 101. If the tissue site 101
is a wound, for example, the tissue interface 108 may partially or
completely fill the wound, or may be placed over the wound. The
tissue interface 108 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
the tissue site 101. For example, the size and shape of the tissue
interface 108 may be adapted to the contours of deep and irregular
shaped tissue sites.
[0028] In some embodiments, the tissue interface 108 may be a
manifold, such as the manifold 112. A "manifold" in this context
generally includes any substance or structure providing a plurality
of pathways adapted to collect or distribute fluid across a tissue
site under negative pressure. For example, a manifold may be
adapted to receive negative pressure from a source and distribute
the negative pressure through multiple apertures across a tissue
site, which may have the effect of collecting fluid from across a
tissue site and drawing the fluid toward the source. In some
embodiments, the fluid path may be reversed or a secondary fluid
path may be provided to facilitate delivering fluid across a tissue
site.
[0029] In some illustrative embodiments, the pathways of a manifold
may be channels interconnected to improve distribution or
collection of fluids across a tissue site. For example, cellular
foam, open-cell foam, reticulated foam, porous tissue collections,
and other porous material such as gauze or felted mat generally
include pores, edges, and/or walls adapted to form interconnected
fluid pathways. Liquids, gels, and other foams may also include or
be cured to include apertures and flow channels. In some
illustrative embodiments, a manifold may be a porous foam material
having interconnected cells or pores adapted to uniformly (or
quasi-uniformly) distribute negative pressure to a tissue site. In
some illustrative embodiments, a manifold may have pores with a
diameter in the range of about 20 microns to about 400 microns. The
foam material may be either hydrophobic or hydrophilic. In one
non-limiting example, a manifold may be an open-cell, reticulated
polyurethane foam such as GranuFoam.RTM. dressing available from
Kinetic Concepts, Inc. of San Antonio, Tex.
[0030] In an example in which the tissue interface 108 may be made
from a hydrophilic material, the tissue interface 108 may also wick
fluid away from a tissue site, while continuing to distribute
negative pressure to the tissue site. The wicking properties of the
tissue interface 108 may draw fluid away from a tissue site by
capillary flow or other wicking mechanisms. An example of a
hydrophilic foam is a polyvinyl alcohol, open-cell foam such as
V.A.C. WhiteFoam.RTM. dressing available from Kinetic Concepts,
Inc. of San Antonio, Tex. Other hydrophilic foams may include those
made from polyether. Other foams that may exhibit hydrophilic
characteristics include hydrophobic foams that have been treated or
coated to provide hydrophilicity.
[0031] The tissue interface 108 may further promote granulation at
a tissue site when pressure within the sealed therapeutic
environment 120 is reduced. For example, any or all of the surfaces
of the tissue interface 108 may have an uneven, coarse, or jagged
profile that can induce microstrains and stresses at a tissue site
if negative pressure is applied through the tissue interface
108.
[0032] In some embodiments, the tissue interface 108 may be
constructed from bioresorbable materials. Suitable bioresorbable
materials may include, without limitation, a polymeric blend of
polylactic acid (PLA) and polyglycolic acid (PGA). The polymeric
blend may also include without limitation polycarbonates,
polyfumarates, and caprolactones. The tissue interface 108 may
further serve as a scaffold for new cell-growth, or a scaffold
material may be used in conjunction with the tissue interface 108
to promote cell-growth. A scaffold is generally a substance or
structure used to enhance or promote the growth of cells or
formation of tissue, such as a three-dimensional porous structure
that provides a template for cell growth. Illustrative examples of
scaffold materials include calcium phosphate, collagen, PLA/PGA,
coral hydroxy apatites, carbonates, or processed allograft
materials.
[0033] In some embodiments, the cover 106 may provide a bacterial
barrier and protection from physical trauma. The cover 106 may also
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 106 may be, for example, an
elastomeric film or membrane that can provide a seal adequate to
maintain a negative pressure at a tissue site for a given
negative-pressure source. In some example embodiments, the cover
106 may be a polymer drape, such as a polyurethane film, that is
permeable to water vapor but impermeable to liquid. Such drapes
typically have a thickness in the range of about 25 to about 50
microns. For permeable materials, the permeability generally should
be low enough that a desired negative pressure may be
maintained.
[0034] An attachment device, such as an attachment device 122, may
be used to attach the cover 106 to an attachment surface, such as
undamaged epidermis, a gasket, or another cover. The attachment
device 122 may take many forms. For example, the attachment device
122 may be a medically-acceptable, pressure-sensitive adhesive that
extends about a periphery, a portion, or an entire sealing member.
In some embodiments, for example, some or all of the cover 106 may
be coated with an acrylic adhesive having a coating weight between
25-65 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 the attachment device 122 may
include a double-sided tape, paste, hydrocolloid, hydrogel,
silicone gel, or organogel.
[0035] The container 110 is representative of a container,
canister, pouch, or other storage component, which can be used to
manage exudates and other fluids withdrawn from a tissue site. In
many environments, a rigid container may be preferred or required
for collecting, storing, and disposing of fluids. In other
environments, fluids may be properly disposed of without rigid
container storage, and a re-usable container could reduce waste and
costs associated with negative-pressure therapy.
[0036] During healing of a tissue site, matrix metalloproteinase
(MMP) is produced. MMPs are an enzyme that aids the process of
remodeling a tissue site. MMPs may be classified as zinc-dependent
endopeptidases that belong to a larger family of proteases that may
be known as the metzincin superfamily. MMPs may be associated with
both physiological and pathological processes, including
morphogenesis, angiogenesis, tissue repair, cirrhosis, arthritis,
and metastasis. Generally, MMPs degrade extracellular matrix
proteins. Extracellular matrix proteins are extracellular
components of a multicellular structure. Extracellular matrix
proteins can support tissue, separate tissues, regulate
communication between the cells of tissues, and regulate the
dynamic behavior of cells. Extracellular matrix proteins can also
store cellular growth factors that can be released when tissue is
damaged. Extracellular matrix proteins aid in regrowth and healing
of tissue by preventing the immune system response at the injury to
prevent inflammation. Extracellular matrix proteins can also aid
the surrounding tissue to repair the damaged tissue rather than
form scar tissue. MMPs assist the extracellular matrix proteins in
tissue healing by breaking down damaged extracellular matrix
proteins when tissue is injured. Breaking down damaged
extracellular matrix proteins allows undamaged extracellular matrix
proteins to integrate with newly formed components. MMPs also
remove biofilms that can cause infection, help establish new blood
vessels in damaged tissue, aid in the migration of epithelial
cells, and remodel scarred tissue. However, MMPs can inhibit
healing of damaged tissue. For example, MMPs in the wrong locations
in a tissue site or too many MMPs in a tissue site can degrade
extracellular matrix proteins that are needed for healing.
Typically, tissue sites that exhibit an increased inflammatory
response may be producing MMPs at rates that can lead to inhibition
of healing. Inflammation can also cause an increased production of
fluid from the tissue site, leading to maceration and other
degenerative conditions that may prolong healing time.
[0037] Excess MMPs may be modulated by adding modulating agents to
the tissue site. A modulating agent may be an agent, such as a
structural protein, that is added to the tissue site. Modulating
agents may include scavenging or sacrificial structures formed from
a protein material. If the sacrificial structure is placed adjacent
a tissue site, the excess MMPs degrade the sacrificial structure
rather than newly formed tissue, reducing existing inflammation and
the likelihood of additional inflammation. Some sacrificial
structures may include sheets of a collagen material that form a
collagen substrate. The collagen substrate may be placed on a
surface of a tissue site or coated onto another substrate, such as
a tissue interface or manifold. Generally, a modulating agent
should be placed in close contact to areas of a tissue site where
the MMPs are active and deleterious to healing.
[0038] Some tissues sites may stall during healing. A stalled
tissue site may be a tissue site that does not follow the desired
healing progression within the desired time frame. A stalled tissue
site may be caused by excess MMPs as well as excess elastases and
bacterial proteases. Elastase and bacterial proteases are types of
proteases that may aid in breaking down proteins. Excess elastase
and bacterial proteases may inhibit healing by breaking down the
new tissue as it develops, preventing the tissue site from healing.
Similar to MMPs, elastases and bacterial proteases may be modulated
by adding modulating agents, such as oxidized regenerated cellulose
(ORC), to the tissue site. The ORC may be stable below a pH of
about 4.4 and negatively charged. If the ORC is placed in the
tissue site, the tissue site may react to raise the pH of the ORC
to the natural pH of the body, producing glucuronic acid that may
aid in the removal of undesired products from the tissue site. The
ORC, being negatively charged, may also attract and bind with
elastase and bacterial proteases, which are positively charged.
[0039] Application of negative-pressure therapy may encourage
granulation and manage wound fluid, enhancing the effectiveness of
the modulating agents. However, most modulating agents, such as a
collagen substrate, are continuous and non-porous. If a collagen
substrate, an ORC substrate, or a combined collagen/ORC substrate
is placed adjacent to a tissue site so that the substrate is in
close contact with the proteases, such as MMPs, elastases, and
bacterial proteases of the tissue site, the substrate may act as a
barrier to the flow of fluids, including negative pressure.
Consequently, modulating agents can inhibit the transmission of
negative pressure to a tissue site, preventing the
negative-pressure therapy from encouraging granulation and managing
wound fluids. Thus, while modulating agents may decrease damage
caused by MMPs, elastases, and bacterial proteases, the modulating
agents may increase maceration, limit granulation, and otherwise
stymie the positive benefits of negative-pressure therapy. For at
least this reason, clinicians are reluctant to use modulating
agents with negative-pressure therapy. Although perforating a
substrate to form holes in the substrate would help to transmit
negative pressure to a tissue site, the material punched from the
holes would be discarded as waste, which is not cost effective.
Even if a sacrificial substrate is perforated, such substrate must
also have holes of sufficient diameter to permit the flow of
negative pressure and sufficient stiffness and strength to
withstand the transmission of negative pressure to the tissue
site.
[0040] These limitations and others may be addressed by the
negative-pressure therapy system 100 that can provide a modulating
agent for proteases including MMPs, elastases, and bacterial
proteases while providing negative pressure to a tissue site. In
some embodiments, the negative-pressure therapy system 100 may
include a dressing 102 having a mesh 114 that includes a plurality
of collagen fibers intersecting with each other to form a network
having a plurality of openings of sufficient size or diameter to
permit the flow of negative pressure through the mesh 114 that
functions as the sacrificial substrate, sacrificial network, or
modulating layer. The openings may be of any shape, but of
sufficient size or area so as not to inhibit the flow of negative
pressure. The collagen fibers may be reinforced by a supporting
material wherein the collagen content of the collagen fibers may be
about 30% of the total content of the collagen fibers. In other
embodiments, the total collagen content of the collagen fibers may
be between about 10% and about 50% of the total content of the
collagen fibers. In some embodiments, the supporting material may
be polyethylene oxide, and the polyethylene oxide may be between
about 90% and about 50% of the total material content of the
collagen fibers. The supporting material may be water soluble. The
supporting material may also be biodegradable. In some embodiments,
the supporting material may take the form of supporting fibers
formed from the supporting material and twisted together with the
collagen fibers to further reinforce the collagen fibers. In some
embodiments, the mesh 114 may include fibers formed from ORC.
[0041] FIG. 2 is a perspective view of a portion of the mesh 114
that illustrates additional details that may be associated with
some example embodiments of the negative-pressure therapy system
100 wherein the mesh 114 is formed from a plurality of collagen
fibers 126, 127. In some embodiments, the mesh 114 may be formed by
weaving, knitting, knotting, linking, or otherwise connecting the
collagen fibers 126, 127 to form a regular pattern of openings or
mesh apertures 130. As illustrated in FIG. 2, the mesh 114 may
comprise a first plurality of collagen fibers 126 aligned
substantially parallel to each other and a second plurality of
collagen fibers 127 also aligned substantially parallel to each
other, wherein the first and second plurality of collagen fibers
126, 127 are positioned adjacent to each other at an angle.
Consequently, the first and second plurality of collagen fibers
126, 127 overlap each other to form a network having the plurality
of openings or mesh apertures 130. The first and second plurality
of collagen fibers 126, 127 intersect with each other to form a
plurality of intersections 136. An intersection 136 of at least two
collagen fibers 126, 127 may be formed by overlapping fibers or
other types of connections between the fibers at an intersection
136.
[0042] The first and second plurality of collagen fibers 126, 127
may be separated from adjacent collagen fibers 126, 127,
respectively, by a distance 132 and 134, respectively, which may be
between about 0.5 mm and about 5 mm. In other embodiments, the
distance 132 and 134 which may be between about 1.0 mm and about
2.5 mm. In some embodiments, the first direction of the distance
132 and the second direction of the distance 134 may be
perpendicular. In some embodiments, the distance 132 and the
distance 134 may be the same. In other embodiments, the angle
formed by the first direction of the distance 132 and the second
direction of the distance 134 may be angles other than
perpendicular, and the distance 132 and the distance 134 may not be
the same.
[0043] In some embodiments, the mesh apertures 130 may have an
average effective diameter of about 1 mm. An effective diameter of
a non-circular area may be a diameter of a circular area having the
same surface area as the non-circular area. For example, the
surface area of a mesh aperture 130 where the distance 132 is 0.5
mm and the distance 134 is 0.5 mm may be 0.25 mm.sup.2. The
diameter of a circular area having a 0.25 mm.sup.2 surface area is
about 0.56 mm; consequently, the effective diameter of the
exemplary mesh aperture 130 is about 0.56 mm. Similarly, if the
distance 132 is about 4 mm and the distance 134 is about 4 mm, the
effective diameter of the mesh aperture 130 may be about 4.51 mm.
In some embodiments, each mesh aperture 130 may have an area formed
by the effective diameter of the mesh aperture 130. In some
embodiments, each mesh aperture 130 may be uniform in area. In
other embodiments, each mesh aperture 130 may not be uniform in
area. If the mesh apertures 130 are not uniform in area, the
average of the areas of the mesh apertures 130 may be between about
0.2 mm.sup.2 and about 20 mm.sup.2. In some embodiments, the mesh
apertures 130 may be square. In other embodiments, the mesh
apertures 130 may form other shapes, such as rectangular,
triangular, circular, ovular, or amorphous shapes.
[0044] In some embodiments, each of the collagen fibers 126, 127
may have a diameter 128. In some embodiments, the diameter 128 may
be no greater than about 1 mm. In some embodiments, the diameter
128 may be about 1 micron. In some embodiments, the diameter 128
may be between about 5 microns and about 50 microns. The
intersections 136 may have a prominence 141. In some embodiments,
the prominence 141 at the intersections 136 may be equal to the
diameter 128 of the collagen fibers 126, 127. In some embodiments,
the prominence 141 may be reduced by compressing the mesh 114
following formation of the mesh 114. The prominences 141 may also
be reduced by passing the mesh 114 through a calender, which may
apply pressure to the mesh 114 to smooth out the mesh 114. In some
embodiments, the prominence 141 may be less than about 1 mm.
[0045] In some embodiments, the mesh 114 may be substantially flat.
For example, the mesh 114 may have a thickness 124, and individual
portions of the mesh 114 may have a minimal tolerance from the
thickness 124. In some embodiments, the thickness 124 of the mesh
114 may be based in part on the diameter 128 of the fibers 126,
127. In some embodiments, the thickness 124 of the mesh 114 may be
about 1 mm, and the tolerance of the thickness 124 may be less than
about 2 mm. In another exemplary embodiment, a tolerance of the
thickness 124 of the mesh 114 may be less than about 1 mm. In other
embodiments, a tolerance of the thickness 124 of the mesh 114 may
be less than about 0.5 mm. In other embodiments, the thickness 124
of the mesh 114 may be between about 5 microns and about 50
microns.
[0046] In some embodiments, the mesh 114 may be formed by an
extrusion process. For example, collagen may be blended with a
polymer, such as poly (lactide-glycolide) or PLGA copolymers that
may be particularly well-suited for the extrusion process. The
blended collagen polymer may be extruded into the mesh 114 having
the plurality of collagen fibers 126, 127 with the plurality of
mesh apertures 130 formed between them.
[0047] In some embodiments, the collagen fibers 126, 127 may be
formed from a plurality of staple fibers. A staple fiber may be a
fiber of a selected standardized length. The collagen fibers 126,
127 may be a combination of staple fibers formed from collagen and
staple fibers formed from a supporting material to reinforce the
collagen material of the staple fibers of collagen. The staple
fibers of collagen may be formed by melt spinning, wet spinning,
electrospinning, or other suitable processes. Melt spinning may
involve melting a collagen in a polymer and squeezing the combined
substance through a spinneret to form the fiber. For example,
collagen split skins may be denatured and dried, ground to a power
on a centrifugal mill, and mixed with glycerol and deionized water.
The solution may be fed into an extruder spinning system to form
fibers. Wet spinning may involve dissolving the collagen in a
polymer to form a coagulating bath having a low pH. Liquid in the
coagulating bath may be evaporated to form a fine fiber. For
example, a collagen dispersion may be prepared using an alkaline
treated bovine and porcine splits that are treated with a solution,
minced, acidified and treated in a colloid mill. The collagen
dispersion can be processed by a cylinder spinning system to spin a
thread that may be coagulated in a bath, air dried, and wound on a
bobbin. Electrospinning may subject a collagen-polymer solution to
an electric field to induce the accumulation of a charge on the
surface of a pendant drop. The charge accumulation generates a
force that directly opposes the force produced by the surface
tension of the drop that, above a critical value of electric field
strength, can cause a charged jet to eject to form fine filaments.
Additional information regarding electrospinning with collagen and
a polyethylene oxide polymer may be described in Lei Huang, et al.
"Engineered collagen--PEO nanofibers and fabrics," J. Biomater.
Sci. Polymer Edn, Vol. 12, No. 9, pp. 979-993 (2001), which is
incorporated by reference for all purposes. The filaments of
collagen may then be cut into standardized lengths to form staple
fibers. In some embodiments, the staple fibers of collagen may have
a length between about 4 mm and about 6 mm.
[0048] The staple fibers formed from a supporting material may be
formed from one or more of polyethylene oxide, alginate, polylactic
aid, other bio-absorbable polymers, polyvinyl alcohol,
polycaprolactones, or polyamides. The staple fibers of the
supporting material may be formed by producing filaments of the
supporting material and cutting the filaments into standardized
lengths. In some embodiments, the staple fibers of the supporting
material may have a length between about 4 mm and about 6 mm.
[0049] The staple fibers of collagen and the staple fibers of the
supporting material may be twisted together and carded to form the
collagen fibers 126, 127. In some embodiments, the collagen content
of the collagen fibers 126, 127 may be about 30% of the total
content of the collagen fibers 126, 127. In other embodiments, the
total collagen content of the collagen fibers 126, 127 may be
between about 10% and about 50% of the total content of the
collagen fibers 126, 127. The remaining content of the collagen
fibers 126, 127 may be the supporting material. For example, in
some embodiments, the supporting material may be polyethylene
oxide, and the polyethylene oxide may be between about 90% and
about 50% of the total material content of the collagen fibers 126,
127. In some embodiments, the collagen fibers 126, 127 may be a
string of collagen elements.
[0050] Referring to FIG. 1, negative pressure may be supplied to
the tissue site 101 through the manifold 112. The manifold 112 may
contract and compress the mesh 114 into a surface of the tissue
site 101, and negative-pressure may be distributed to the tissue
site 101 through the mesh apertures 130. The mesh 114 may readily
absorb moisture from the tissue site 101. As the mesh 114 absorbs
moisture from the tissue site 101, the collagen fibers 126, 127 of
the mesh 114 may expand. The mesh apertures 130 may be sized so
that negative pressure may continue to be distributed to the tissue
site 101 through the mesh 114. The compression of the mesh 114 by
the manifold 112 may also cause the mesh 114 to be pushed into the
manifold 112 and may allow the manifold 112 to contact the surface
of the tissue site 101, providing microstrain and delivering
perfusion. The mesh 114 may not inhibit granulation, but swell and
disperse into the manifold 112 to provide MMP modulation without
restricting the flow of negative-pressure to the tissue site
101.
[0051] FIG. 3 is a perspective view of a portion of a mesh 214,
illustrating additional details that may be associated with other
example embodiments of the negative-pressure therapy system 100.
The mesh 214 may be similar to and operate as described above with
respect to the mesh 114. Similar elements may have similar
reference numbers that are indexed to 200. As shown in FIG. 3, the
mesh 214 may include a plurality of supporting fibers 238 and a
plurality of collagen fibers 226. In some embodiments, the collagen
fibers 226 and the supporting fibers 238 may be woven together to
form a network or a mesh, such as the mesh 214. In some
embodiments, the collagen fibers 226 and the supporting fibers 238
may be woven together so that the collagen fibers 226 and the
supporting fibers 238 overlap at intersections 236. In some
embodiments, the collagen fibers 226 and the supporting fibers 238
may be alternated. For example, a plurality of supporting fibers
238 may be laid in parallel rows, and a plurality of collagen
fibers 226 may be laid with the plurality of supporting fibers 238
so that a collagen fiber 226 is between adjacent supporting fibers
238 to form a first layer of fibers 226, 238. A second layer of
fibers 227, 239 having a similar makeup to the first layer of
fibers 226, 238 may be woven with the first layer of fibers 226,
238 to produce the mesh 214 of FIG. 3.
[0052] The mesh 214 may include mesh apertures 230 formed by a
distance 234 and a distance 232 between adjacent fibers. The mesh
apertures 230 of the mesh 214 may have an average effective
diameter between about 1 mm and about 5 mm. The mesh 214 of FIG. 3
may also include prominences 241 at the intersections 236 of the
overlapping fibers, such as the collagen fibers 226, 227 and the
supporting fibers 238, 239. The collagen fibers 226, 227 may also
have a diameter 228.
[0053] Generally, a thickness 224 of the mesh 214, the collagen
fibers 226, 227, the diameter 228, the mesh apertures 230, the
distance 232, the distance 234, the intersections 236, and the
prominence 241 may be similar to and operate as described above
with respect to the mesh 114, the thickness 124 of the mesh 114,
the collagen fibers 126, 127, the diameter 128, the mesh apertures
230, the distance 132, the distance 134, the intersections 136, and
the prominence 141, respectively.
[0054] The supporting fibers 238, 239 may be fibers formed from the
supporting material and having little or no collagen content. As
described above, the supporting material may be one or more of
polyethylene oxide, alginate, polylactic aid, other bio-absorbable
polymers, polyvinyl alcohol, polycaprolactones, or polyamides. The
supporting fibers 238, 239 may be formed from a monofilament, a
plurality of twisted monofilaments, a plurality of filaments, or a
plurality of staple fibers. A monofilament may be a single
filament. In some embodiments, a monofilament may be made from a
single synthetic fiber of plastic, for example. Monofilaments may
have a tensile strength related to a diameter of the monofilament
and the type of material from which the monofilament is formed. A
filament may be a fiber that is formed in a continuous or
near-continuous length. Each of the supporting fibers 238, 239 may
have a diameter 240. In some embodiments, the diameter 240 may be
no greater than about 1 mm.
[0055] FIG. 4 is a schematic view of a portion of a mesh 314,
illustrating additional details that may be associated with other
example embodiments of the negative-pressure therapy system 100.
The mesh 314 may be similar to and operate as described above with
respect to the mesh 114. Similar elements may have similar
reference numbers that are indexed to 300. In some embodiments, a
plurality of collagen fibers 326 and a plurality of supporting
fibers 338 may be formed into the non-woven mesh 314. For example,
the collagen fibers 326 and the supporting fibers 338 may be
dispersed on a conveyor belt, and spread in a uniform web by a
wetlaid, an airlaid, or a carding/crosslapping process. The
collagen fibers 326 and the supporting fibers 338 may be bonded
thermally or by using a resin to form the mesh of the mesh 314. For
example, the collagen fibers 326 and the supporting fibers 338 may
overlap and form intersections 336 where the collagen fibers 326
and the supporting fibers 338 overlap with other fibers. The
overlapping fibers of the mesh 314 may also form openings, such as
mesh apertures 330. As shown in FIG. 4, the mesh apertures 330 may
not be uniform in size. The mesh apertures 330 of the mesh 314 may
have an average effective diameter between about 1 mm and about 5
mm. If the mesh apertures 330 are not uniform in size the average
of the effective diameters of the mesh apertures 330 may be between
about 1 mm and about 5 mm.
[0056] In some embodiments, the mesh 314 may also be formed in a
spunlaid process having only the collagen fibers 326. Spunlaid
nonwovens may be made in a continuous process by forming the
collagen fibers 326 as described above. The collagen fibers 326 may
be dispersed into a web by physical deflectors or with air streams
without further cutting the collagen fibers 326.
[0057] Generally, a thickness of the mesh 314, the collagen fibers
326, a diameter of the collagen fibers 326, the mesh apertures 330,
the intersections 336, the supporting fibers 338, and a diameter of
the supporting fibers 338 may be similar to and operate as
described above with respect to the mesh 114, the thickness 124 of
the mesh 114, the collagen fibers 126, 127, the diameter 128, the
mesh apertures 130, the intersections 136, the supporting fibers
238, and the diameter 240 of the supporting fibers 238
respectively.
[0058] FIG. 5 is a perspective view of a portion of a mesh 414
having collagen and oxidized regenerated cellulose (ORC),
illustrating additional details that may be associated with other
example embodiments of the negative-pressure therapy system 100.
The mesh 414 may be similar to and operate as described above with
respect to the mesh 114. Similar elements may have similar
reference numbers that are indexed to 400. As shown in FIG. 5, the
mesh 414 may include a plurality of ORC fibers 448 and a plurality
of collagen fibers 426. In some embodiments, the collagen fibers
426 and the ORC fibers 448 may be woven together to form a network
or a mesh, such as the mesh 414. In some embodiments, the collagen
fibers 426 and the ORC fibers 448 may be woven together so that the
collagen fibers 426 and the ORC fibers 448 overlap at intersections
436. In some embodiments, the collagen fibers 426 and the ORC
fibers 448 may be alternated. For example, a plurality of ORC
fibers 448 may be laid in parallel rows, and a plurality of
collagen fibers 426 may be laid with the plurality of ORC fibers
448 so that a collagen fiber 426 is between adjacent ORC fibers 448
to form a first layer of fibers 426, 448. A second layer of fibers
427, 449 having a similar makeup to the first layer of fibers 426,
438 may be woven with the first layer of fibers 426, 438 to produce
the mesh 414 of FIG. 5.
[0059] The mesh 414 may include mesh apertures 430 formed by a
distance 434 and a distance 432 between adjacent fibers. The mesh
apertures 430 of the mesh 414 may have an average effective
diameter between about 1 mm and about 5 mm. The mesh 414 of FIG. 5
may also include prominences 441 at the intersections 436 of the
overlapping fibers, such as the collagen fibers 426, 427 and the
ORC fibers 448, 449. The collagen fibers 426, 427 may also have a
diameter 428.
[0060] Generally, a thickness 424 of the mesh 414, the collagen
fibers 426, 427, the diameter 428, the mesh apertures 430, the
distance 432, the distance 434, the intersections 436, and the
prominence 441 may be similar to and operate as described above
with respect to the mesh 114, the thickness 124 of the mesh 114,
the collagen fibers 126, 127, the diameter 128, the mesh apertures
430, the distance 132, the distance 134, the intersections 136, and
the prominence 141, respectively.
[0061] The ORC fibers 448, 449 may be fibers formed from the
oxidized regenerated cellulose (ORC). ORC may be a regenerated
polysaccharide polymer that may be extruded into fibers. In some
embodiments, the ORC fibers 448, 449 may be fibers formed from
oxidized cellulose. Oxidized cellulose may be a water insoluble
derivative of cellulose produced from cellulose and an oxidizing
agent that is extruded into fibers. In some embodiments, the ORC
fibers 448, 449 may be a fiber formed from the supporting material
having ORC that has been ground into a power, dispersed within or
coating the fibers of the supporting material. The ORC fibers 448,
449 may be formed from a monofilament, a plurality of twisted
monofilaments, a plurality of filaments, or a plurality of staple
fibers. Each of the ORC fibers 448, 449 may have a diameter 450. In
some embodiments, the diameter 450 may be no greater than about 1
mm.
[0062] In some embodiments, the ORC fibers 448, 449 may be disposed
with the collagen fibers 426, 427 in a woven as illustrated in FIG.
5. In other embodiments, the ORC fibers 448, 449 may be disposed
with the collagen fibers 426, 427 in a non-woven, similar to the
mesh 314 of FIG. 4. In some embodiments, the ORC fibers 448, 449
may comprise about 45% of the mesh 414. The collagen fibers 427,
428 may comprise about 55% of the mesh 414. In some embodiments,
about 45% of the non-supporting material of the mesh 414 may be ORC
material, and about 55% of the non-supporting material of the mesh
414 may be collagen material.
[0063] As described above with respect to the mesh 114, negative
pressure may be supplied to the tissue site 101 through the
manifold 112, contracting and compressing the mesh 414 into a
surface of the tissue site 101. Negative pressure may be
distributed to the tissue site 101 through the mesh apertures 430.
The mesh 414 may readily absorb moisture from the tissue site 101.
As the mesh 414 absorbs moisture from the tissue site 101, the
collagen fibers 426, 427 and the ORC fibers 448, 439 of the mesh
414 may expand. The mesh apertures 430 may be sized so that
negative pressure may continue to be distributed to the tissue site
101 through the mesh 414. The compression of the mesh 414 by the
manifold 112 may also cause the mesh 414 to be pushed into the
manifold 112 and may allow the manifold 112 to contact the surface
of the tissue site 101, providing microstrain and delivering
perfusion. The mesh 414 may not inhibit granulation, but swell and
disperse into the manifold 112 to provide MMP modulation, elastase
modulation, and bacteria protease modulation without restricting
the flow of negative-pressure to the tissue site 101.
[0064] The systems, apparatuses, and methods described herein may
provide significant advantages. For example, a flexible and
compatible method to apply and deliver the benefits of protease
modulation and negative pressure therapy may be provided. In some
embodiments, the mesh may provide MMP modulation without hindering
the delivery of negative pressure to the tissue site and allowing
creation of microstrain. In some embodiments, the mesh may also
provide elastase and bacteria protease modulation in addition to
MMP modulation. The mesh may also withstand heavy exudate flows
without requiring removal. The mesh may be placed directly onto the
tissue site and efficiently uses the available collagen while
placing the collagen in direct contact with the tissue site. The
mesh may be fully bioabsorbable so could be placed in deep hard to
access tissue sites where the removal of devices may not be
desirable.
[0065] While shown in a few illustrative embodiments, a person
having ordinary skill in the art will recognized that the systems,
apparatuses, and methods described herein are susceptible to
various changes and modifications. 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.
[0066] The appended claims set forth novel and inventive aspects of
the subject matter 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 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 defined by the appended
claims.
* * * * *