Patent Description:
While the clinical benefits of negative-pressure therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients.

<CIT>, <CIT>, <CIT>, <CIT>, and <CIT> each discuss wound dressings.

There is provided an apparatus for treating a tissue site which comprises a contact layer formed from a compressible material. The contact layer comprises a first surface, a second surface, and a plurality of apertures extending at least partially through the contact layer. At least a portion of the apertures include a first plurality of orifices in the first surface having a diameter in a first diameter range and at least a portion of the apertures include a second plurality of orifices in the second surface having a diameter in a second diameter range. The contact layer also comprises a cover configured to form a sealed space including the contact layer and the tissue site. The first diameter range is from about <NUM> to about <NUM>. The second diameter range is from about <NUM> to about <NUM>. In use, either the first surface or the second surface of the contact layer contacts the tissue site.

Embodiments described with reference to <FIG> fall within the scope of the appended claims. The remaining figures relate to embodiments which are useful for understanding the claimed subject matter but are not within the scope of the claimed subject matter.

<FIG> is a simplified schematic diagram of an example embodiment of a therapy system <NUM> that can provide negative-pressure therapy in accordance with this specification.

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. 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 applied to a tissue site to grow additional tissue that may be harvested and transplanted.

The therapy system <NUM> may include a negative-pressure supply, and may include or be configured to be coupled to a distribution component, such as a dressing. 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, a dressing <NUM> may be fluidly coupled to a negative-pressure source <NUM>, as illustrated in <FIG>. A dressing may include a cover, a tissue interface, or both in some embodiments. The dressing <NUM>, for example, may include a cover <NUM> and a contact layer <NUM>. A regulator or a controller, such as a controller <NUM>, may also be coupled to the negative-pressure source <NUM>.

In some embodiments, a dressing interface <NUM> may facilitate coupling the negative-pressure source <NUM> to the dressing <NUM>. For example, such a dressing interface may be the SENSAT. ™ Dressing available from Acelity L. The therapy system <NUM> may optionally include a fluid container, such as a container <NUM>, coupled to the dressing <NUM> and to the negative-pressure source <NUM>.

As illustrated in <FIG>, for example, the therapy system <NUM> may include a pressure sensor <NUM>, an electric sensor <NUM>, or both, coupled to the controller <NUM>. The pressure sensor <NUM> may also be coupled or configured to be coupled to a distribution component and to the negative-pressure source <NUM>.

Components 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. 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 dressing <NUM> to the container <NUM> in some embodiments.

For example, the negative-pressure source <NUM> may be directly coupled to the controller <NUM>, and may be indirectly coupled to the dressing <NUM> through the container <NUM>.

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.

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 a 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.

"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 dressing <NUM>. 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 -<NUM> Hg (-<NUM> Pa) and -<NUM> Hg (-<NUM> kPa). Common therapeutic ranges are between -<NUM> Hg (-<NUM> kPa) and -<NUM> Hg (-<NUM> kPa).

A negative-pressure supply, such as the negative-pressure source <NUM>, 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. For example, in some embodiments, the negative-pressure source <NUM> may be combined with the controller <NUM> and other components into a therapy unit. 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.

Operating parameters may include the power applied to the negative-pressure source <NUM>, the pressure generated by the negative-pressure source <NUM>, or the pressure distributed to the contact layer <NUM>, for example.

Sensors, such as the pressure sensor <NUM> or the electric sensor <NUM>, 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. For example, the pressure sensor <NUM> and the electric sensor <NUM> may be configured to measure one or more operating parameters of the therapy system <NUM>. In some embodiments, the pressure sensor <NUM> 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, for example, the pressure sensor <NUM> may be a piezoresistive strain gauge. The electric sensor <NUM> may optionally measure operating parameters of the negative-pressure source <NUM>, such as the voltage or current, in some embodiments. Preferably, the signals from the pressure sensor <NUM> and the electric sensor <NUM> are suitable as an input signal to the controller <NUM>, but some signal conditioning may be appropriate in some embodiments.

In some embodiments, the cover <NUM> may provide a bacterial barrier and protection from physical trauma. The cover <NUM> 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 <NUM> 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. The cover <NUM> may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least <NUM>/m<NUM> per twenty-four hours in some embodiments. In some example embodiments, the cover <NUM> 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 <NUM>-<NUM> microns. For permeable materials, the permeability generally may be low enough that a desired negative pressure may be maintained.

An attachment device may be used to attach the cover <NUM> to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many 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. In some embodiments, for example, some or all of the cover <NUM> may be coated with an acrylic adhesive having a coating weight between <NUM>-<NUM> grams per square meter (g. 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.

The contact layer <NUM> can be generally adapted to contact a tissue site. The contact layer <NUM> may be partially or fully in contact with the tissue site. If the tissue site is a wound, for example, the contact layer <NUM> may partially or completely fill the wound, or may be placed over the wound. The contact layer <NUM> 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 contact layer <NUM> may be adapted to the contours of deep and irregular shaped tissue sites. Moreover, any or all of the surfaces of the contact layer <NUM> may have projections or an uneven, course, or jagged profile that can induce strains and stresses on a tissue site, which can promote granulation at the tissue site.

In some embodiments, the contact layer <NUM> may comprise or consist of two substantially planar surfaces and a depth or thickness orthogonal to the planar surfaces. The contact layer <NUM> comprises a first surface and a second surface. The first surface and/or second surface may have a surface area from about <NUM><NUM> to about <NUM><NUM>, or from about <NUM><NUM> to about <NUM><NUM>, or from about <NUM><NUM> to about <NUM><NUM>.

In some embodiments, the contact layer <NUM> may comprise or consist of a manifold. 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 pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute 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. In some illustrative embodiments, the pathways of a manifold may be interconnected to improve distribution or collection of fluids across a tissue site.

In some embodiments, the contact layer <NUM> may be formed from a suitably compressible material. For example, in some illustrative embodiments, the contact layer <NUM> may comprise or consist of a porous foam material having interconnected cells or pores. For example, the contact layer <NUM> may comprise or consist of cellular foam such as open-cell foam. The open-cell foam may be reticulated foam. Liquids, gels, and other foams may also include or be cured to include fluid pathways. In some embodiments, the contact layer <NUM> may comprise projections that form interconnected fluid pathways. For example, the contact layer <NUM> may be molded to provide surface projections that define interconnected fluid pathways. In some embodiments, the foam may have an average pore size that varies according to needs of a prescribed therapy. For example, in some embodiments, the contact layer <NUM> may be foam having pore sizes in a range of <NUM>-<NUM> microns. In some embodiments, the contact layer <NUM> may have a tensile strength that also varies according to needs of a prescribed therapy.

In some embodiments, the foam material of the contact layer <NUM> may be characterized with respect to density. For example, in some embodiments, the contact layer <NUM> may be characterized as a relatively dense material. In various embodiments, the contact layer <NUM> may have a density of about <NUM>/m<NUM> to about <NUM>/m<NUM> or about <NUM>/m<NUM> to about <NUM>/m<NUM>.

In some embodiments, the contact layer <NUM> may comprise a single foam layer. In some embodiments, the contact layer <NUM> may comprise two or more layers that have been joined together to form the contact layer <NUM>. The two or more sublayers may be joined together by flame lamination or by a reactive adhesive, for example, a heat reactive adhesive system such as a hot melt adhesive or a chemically reactive adhesive system such as isocyanate adhesives, epoxy adhesives, silane adhesives, or combinations thereof.

In some embodiments, the contact layer <NUM> may be hydrophobic. In some an embodiments, the hydrophobic characteristics may prevent the foam from directly absorbing fluid, such as wound exudate, but may allow fluid to pass through a fluid pathway. For example, in some embodiments, the foam may be polyurethane foam, a silicone foam, a polyether block amide foam, such as PEBAX®, an acrylic foam, a polyvinyl chloride (PVC) foam, a polyolefin foam, a polyester foam, a polyamide foam, a thermoplastic elastomer (TPE) foam such as a thermoplastic vulcanizate (TPV) foam, or another crosslinking elastomeric foam such as foams formed from styrene-butadiene rubber (SBR) and ethylene propylene diene monomer (EPDM) rubber. For example, the contact layer <NUM> may comprise hydrophobic, open-cell foam. In one non-limiting example, the contact layer <NUM> may comprise a reticulated polyurethane foam such as the foam employed in the V. ® GRANUFOAM™ Dressing or the foam employed in the V. VERAFLO™ Dressing, both available from Acelity L.

In other embodiments, the contact layer <NUM> may be hydrophilic. In some embodiments, the hydrophillic characteristics may be effective to wick fluid while also continuing to distribute negative pressure to the tissue site. In some embodiments, the wicking properties of the contact layer <NUM> may draw fluid away from the tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic foam may include a polyvinyl alcohol or polyether, open-cell foam. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity. For example, the contact layer <NUM> may be a treated open-cell polyurethane foam. In one non-limiting example, the contact layer <NUM> may comprise a polyvinyl alcohol, open-cell foam such as the foam employed in the V. WHITEFOAM™ Dressing available from Acelity L.

In some embodiments, the contact layer <NUM> may further promote granulation at a tissue site when pressure within a sealed therapeutic environment is reduced. For example, any or all of the surfaces of the contact layer <NUM> may have an uneven, coarse, or jagged profile that can induce microstrains and stresses at a tissue site if negative pressure is applied through contact layer <NUM>.

The contact layer <NUM> comprises a plurality of apertures extending at least partially through the thickness of the contact layer <NUM>. The contact layer <NUM> is configurable such that at least a portion of the apertures includes a first plurality of orifices having a diameter in a first diameter range, and such that at least a portion of the apertures includes a second plurality of orifices having a diameter in a second diameter range. The term "aperture" in this context broadly refers to a void space extending some depth into or through a contact layer. The term "orifice" in this context more narrowly refers to an opening to an aperture in a plane in which an aperture intersects either the first surface or the second surface of the contact layer <NUM>.

The first diameter range is about <NUM> to about <NUM>. The second diameter range is from about <NUM> to about <NUM>. Suitable sizes for the first orifice and the second orifice may be determined based upon the particular needs of a prescribed therapy.

In some embodiments, a contact layer may comprise a plurality of apertures extending through the contact layer, each having an orifice within the first diameter range and an orifice within the second diameter range. For example, <FIG> is a simplified cutaway view of an example embodiment of a contact layer <NUM> including a plurality of apertures <NUM> extending through the contact layer <NUM>. The apertures <NUM> may each have a first orifice <NUM> having a diameter in the first diameter range and a second orifice <NUM> having a diameter in the second diameter range. The apertures <NUM> may have a suitable transitional shape between the first orifice <NUM> and the second orifice <NUM>. For example, in the embodiment <FIG>, the apertures <NUM> have a variable diameter, and may define a conical frustum void-space. In some embodiments, the first orifices <NUM> may be disposed on a first surface <NUM> of the contact layer <NUM> and the second orifices <NUM> may be disposed on a second surface <NUM> of the contact layer <NUM>.

<FIG> is a simplified cutaway view of another example embodiment of a contact layer <NUM> including a plurality of apertures <NUM> extending through the contact layer <NUM> and having a first orifice <NUM> having a diameter in the first diameter range and a second orifice <NUM> having a diameter in the second diameter range. In the embodiment of <FIG>, the aperture <NUM> may define at least a portion of a hyperboloidic void-space, for example a "bottle-shaped" void-space. The first orifices <NUM> may be disposed on a first surface <NUM> of the contact layer <NUM> and the second orifices <NUM> may be disposed on a second surface <NUM> of the contact layer <NUM>.

<FIG> is a simplified cutaway view of another example embodiment of a contact layer <NUM> including a plurality of apertures <NUM> extending through the contact layer <NUM> and having a first orifice <NUM> having a diameter in the first diameter range and a second orifice <NUM> having a diameter in the second diameter range. The contact layer <NUM> may comprise a first sublayer <NUM> joined to a second sublayer <NUM>. In the embodiment <FIG>, the apertures <NUM> include a first portion <NUM> extending through the first sublayer <NUM> and a second portion <NUM> extending through the second sublayer <NUM>. As shown in the example of <FIG>, the first portion <NUM> may be narrower than the second portion <NUM>. The first orifices <NUM> may be disposed on a first surface <NUM> of the contact layer <NUM> and the second orifices <NUM> may be disposed on a second surface <NUM> of the contact layer <NUM>.

A contact layer comprises a plurality of apertures extending only partially through the contact layer. A first portion of the apertures may extend from a first surface and have orifices within the first diameter range. A second portion of the apertures may extend from a second surface and have orifices within the second diameter range. <FIG> is a simplified cutaway view of another example embodiment of a contact layer <NUM> comprising a first sublayer <NUM> joined to a second sublayer <NUM>. A first plurality of apertures <NUM> having orifices within the first diameter range may extend through the first sublayer <NUM>. A second plurality of apertures <NUM> having orifices within the second diameter range may extend through the second sublayer <NUM>. The first plurality of apertures <NUM> may be offset with respect to the second plurality of apertures <NUM>, for example, such that the first plurality of apertures <NUM> and the second plurality of apertures <NUM> each extend only partially through the contact layer <NUM>. The first orifices <NUM> may be disposed on a first surface <NUM> of the contact layer <NUM> and the second orifices <NUM> may be disposed on a second surface <NUM> of the contact layer <NUM>.

In some embodiments, a contact layer may comprise a plurality of removable portions. The plurality of removable portions may have apertures including orifices in a first diameter range. The removable portions may be removable from the contact layer to form apertures including orifices in a second diameter range. <FIG> is a simplified cutaway view of another example embodiment of a contact layer <NUM>. The contact layer <NUM> may comprise a plurality of removable portions <NUM>. Each of the removable portions may include a first aperture <NUM> having first orifices <NUM> in the first diameter range. Each of the removable portions <NUM> may be fitted within a second aperture <NUM> of the contact layer <NUM>. In some embodiments, the removable portions <NUM> may comprise a material separate from the contact layer <NUM> that is inserted within the second apertures <NUM> and held in place, for example, by friction. In some, other embodiments, the removable portions <NUM> may be formed from the material that also forms the contact layer <NUM>. For example, in such embodiments, the removable portions <NUM> may be formed by cutting or perforating the contact layer <NUM> and leaving the removable portions <NUM> in place.

<FIG> is another simplified cutaway view of the embodiment of the contact layer <NUM> of <FIG>, illustrating the removable portions <NUM> removed. In some embodiments, each of the removable portions <NUM> may be removable to yield the second apertures <NUM> having second orifices <NUM> in the second diameter range. In some embodiments, the first apertures <NUM>, the second apertures <NUM>, or both may have a substantially constant diameter. For example, each of the first apertures <NUM> may include two first orifices <NUM> in the first diameter range and each of the second apertures <NUM> may include two second orifices <NUM> in the second diameter range.

In some, other embodiments, the first apertures <NUM>, the second apertures <NUM>, or both may have a diameter that varies over the thickness of the contact layer <NUM>. For example, each of the first apertures <NUM> may include two orifices having different diameters, each of the second apertures <NUM> may include two orifices having different diameters. For example, the first apertures <NUM>, the second apertures <NUM>, or both may define at least a portion of a conical void-space, a hyperboloidic void-space, or the like. In such embodiments, the contact layer may be configurable to provide orifices having diameters within a first diameter range, orifices having diameters within a second diameter range, orifices having diameters within a third diameter range, and orifices having diameters within a fourth diameter range.

In some embodiments, a contact layer may comprise a first plurality of apertures including orifices having diameters within a first diameter range and a second plurality of apertures including orifices having diameters within a second diameter range. <FIG> is a simplified perspective view of another example embodiment of a contact layer <NUM>. The contact layer <NUM> may include a first plurality of apertures <NUM> and a second plurality of apertures <NUM>. The first plurality of apertures <NUM> and the second plurality of apertures <NUM> may extend partially or entirely through the contact layer <NUM>. Each of the first plurality of apertures <NUM> may include an orifice <NUM> having a diameter within a first diameter range and each of the second plurality of apertures <NUM> may include an orifice <NUM> having a diameter within a second diameter range. In some embodiments, the first plurality of apertures <NUM> may be grouped together and the second plurality of apertures <NUM> may also be grouped together. For example, the first plurality of apertures <NUM> may be generally disposed in a first portion of the contact layer <NUM> and the second plurality of apertures <NUM> may be generally disposed in a second portion of the contact layer <NUM>. The contact layer <NUM> may be configurable in either a first configuration or a second configuration, for example, such that either the orifices <NUM> having a diameter within a first diameter range or the orifices <NUM> having a diameter within a second diameter range are disposed centrally with respect to the contact layer. For example, <FIG> illustrates the contact layer <NUM> of <FIG> in a first conformation in which the contact layer <NUM> is coiled such that the orifices <NUM> having a diameter within a first diameter range are disposed centrally after the contact layer <NUM> has been formed into a spiral. In some embodiments, the contact layer may be provided in such a spiral conformation. Also for example, <FIG> illustrates the contact layer <NUM> of <FIG> in a second conformation in which the contact layer <NUM> is coiled such that the orifices <NUM> having a diameter within a second diameter range are disposed centrally after the contact layer <NUM> has been formed into a spiral.

In various embodiments, the first surface and/or the second surface of the contact layer <NUM> may have any suitable shape, examples of which include but are not limited to, triangles, squares, rectangles, ellipses, circles, ovals, and various polygons having four, five, six, seven, eight, or more sides. The shape and area of the first surface and the second surface may be customized to the location and type of tissue site onto which the contact layer <NUM> is to be applied. In some embodiments, the contact layer <NUM> may have a thickness from about <NUM> to about <NUM>, for example, from about <NUM> to about <NUM>, or from about <NUM> to about <NUM>, or from about <NUM> to about <NUM>, or from about <NUM> to about <NUM>, or from about <NUM> to about <NUM>.

In some embodiments, the contact layer <NUM> may be configurable into a one of multiple, potential sizes or shapes, as desired. For example, in some embodiments, the contact layer <NUM> may comprise one or more separation-lines, such as perforations, slits, splits, indentions, or the like. For example, the separation-lines may enable the contact layer <NUM> to be conformed to a tissue site having a particular size or shape by a user without the use of additional tools. For example, the separation-lines may enable to user to divide the contact layer <NUM> into various portions. In various embodiments, the separation-lines may be disposed within the contact layer <NUM> in any suitable pattern or combination of patterns such that, when separated along the separation-lines, one or more of the resultant portions of the contact layer <NUM> have a desired size and/or shape. The perforations may allow a contact layer <NUM> to be customized to one of multiple sizes or shapes. The contact layer <NUM> may offer multiple combinations of lines along which the contact layer <NUM> can be separated, for example, such that multiples potential size and shape combinations are possible.

For example, in the embodiment of <FIG> the contact layer <NUM> is spirally-shaped and includes perforations <NUM> disposed within the contact layer <NUM> in a spiral. <FIG> illustrates a perspective view of the contact layer <NUM> of <FIG>. The contact layer <NUM> may be separated along some portion of the perforations <NUM> to yield a spiral having a desired size.

In the embodiment of <FIG> the contact layer <NUM> is elliptically-shaped and includes perforations <NUM> disposed within the contact layer <NUM> in a plurality of concentric ellipses. <FIG> illustrates a perspective view of the contact layer <NUM> of <FIG>. The contact layer <NUM> may be separated along the perforations <NUM> of one of the ellipses to yield an ellipse of a desired size.

In the embodiment of <FIG> the contact layer <NUM> is elliptically-shaped and includes perforations <NUM> disposed within the contact layer <NUM> in a spiral. <FIG> illustrates a perspective view of the contact layer <NUM> of <FIG>. The contact layer <NUM> may be separated along some portion of the perforations <NUM> to yield a spiral having a desired size.

In the embodiment of <FIG> the contact layer <NUM> is round and includes perforations <NUM> disposed within the contact layer <NUM> in a plurality of concentric circles. <FIG> illustrates a perspective view of the contact layer <NUM> of <FIG>. The contact layer <NUM> may be separated along the perforations <NUM> of one of the circles to yield a circle of a desired size.

In the embodiment of <FIG> the contact layer <NUM> is rectangular and includes perforations <NUM> disposed within the contact layer <NUM> in a plurality of lines extending in multiple directions. <FIG> illustrates a perspective view of the contact layer <NUM> of <FIG>. The contact layer <NUM> may be separated along the perforations <NUM> of one or more of the lines to form a desired size and shape.

In the embodiment of <FIG> the contact layer is an oval and includes perforations <NUM> disposed within the contact layer <NUM> in an oval and in a line. <FIG> illustrates a perspective view of the contact layer <NUM> of <FIG>. The contact layer <NUM> may be separated along the perforations <NUM> of one or more of the lines to form a desired size and shape.

In the embodiment of <FIG> the contact layer <NUM> is an oval and includes perforations <NUM> disposed within the contact layer <NUM> in concentric circles and oval and in lines radiating from the center. <FIG> illustrates a perspective view of the contact layer <NUM> of <FIG>. The contact layer <NUM> may be separated along the perforations <NUM> of one or more of the lines to form a desired size and shape.

In some embodiments, the contact layer <NUM> may be provided as a part of a kit. In various embodiments, for example, the kit may include a contact layer <NUM>, a secondary layer, a cover, or combinations thereof. Generally, a secondary layer may comprise fluid pathways interconnected so as to improve distribution or collection of fluids. For example, in some embodiments, a secondary layer may comprise or consist essentially of a porous material. Examples of suitable porous material that can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. In some examples, a secondary layer may comprise or consist essentially of reticulated polyurethane foam.

In some embodiments, the kit may include two or more contact layers <NUM>, two or more secondary layers, or combinations thereof. The two or more contact layer <NUM> may vary with respect to various parameters such as thickness; density; presence, size, number, and/or distribution of apertures; or the like. For example, the kit may include a contact layer <NUM> having a particular property such as thickness, density, or apertures and another contact layer <NUM> having another property. Similarly, the two or more secondary layers may vary with respect to various properties, such as thickness, density, or porosity.

For example, <FIG> illustrates an embodiment of a kit <NUM> including a first contact layer <NUM>, a second contact layer <NUM>, and a secondary layer <NUM>. The first contact layer <NUM> may include apertures while apertures may be absent from the second contact layer <NUM>. The first contact layer <NUM> and the second contact layer <NUM> may each include perforations, enabling the first contact layer <NUM> and the second contact layer <NUM> to be conformed to a portion of a tissue site. For example, in some embodiments the first contact layer <NUM> may be conformed to a first portion of a tissue site and the second contact layer <NUM> may be conformed to a second portion of a tissue site, depending upon the desired therapy of the tissue site.

<FIG> illustrates an embodiment of a kit <NUM> including a first contact layer <NUM>, a second contact layer <NUM>, and a first secondary layer <NUM>, and a second secondary layer <NUM>. The first contact layer <NUM> and the second contact layer <NUM> may vary as to thickness and the first secondary layer <NUM> and the second secondary layer <NUM> may also vary as to thickness. In various embodiments, the first secondary layer <NUM> and the second secondary layer <NUM> may be used separately or together to yield a desired thickness. Similarly, the first contact layer <NUM> and the second contact layer <NUM> may be used separately or together to yield a desired thickness, according to the needs of a particularly therapy.

In operation, a contact layer may be employed in treating a tissue site, for example, tissue having debris that may be desirably disrupted. For example, the tissue site may include biofilms, necrotic tissue, lacerated tissue, devitalized tissue, contaminated tissue, damaged tissue, infected tissue, exudate, highly viscous exudate, fibrinous slough, and/or other material that can generally be referred to as debris. Such debris may inhibit the efficacy of tissue treatment and slow the healing of the tissue site.

As an example, during treatment of a tissue site, a biofilm may develop on or in the tissue site. Biofilms may include a microbial infection that can cover a tissue site and impair healing of the tissue site. Biofilms can also lower the effectiveness of topical antibacterial treatments by preventing the topical treatments from reaching the tissue site. The presence of biofilms can increase healing times, reduce the efficacy and efficiency of various treatments, and increase the risk of a more serious infection. Additionally or alternatively, some tissue sites may not heal according to the normal medical protocol and may develop areas of necrotic tissue. Necrotic tissue may include dead tissue resulting from infection, toxins, or trauma that caused the tissue to die faster than the tissue can be removed by the normal body processes that regulate the removal of dead tissue. Sometimes, necrotic tissue may be in the form of slough, which may include a viscous liquid mass of tissue. Generally, slough is produced by bacterial and fungal infections that stimulate an inflammatory response in the tissue. Slough may be a creamy yellow color and may also be referred to as pus. Necrotic tissue may also include eschar. Eschar may be a portion of necrotic tissue that has become dehydrated and hardened. Eschar may be the result of a burn injury, gangrene, ulcers, fungal infections, spider bites, or anthrax. Conventionally, eschar may be generally difficult to move without the use of surgical cutting instruments.

In various embodiments, the debris may cover all or a portion of the tissue site. If the debris is at or in in the tissue site, the tissue site may be treated with various processes to disrupt the debris. Examples of disruption can include softening of the debris, separation of the debris from desired tissue, such as the subcutaneous tissue, preparation of the debris for removal from the tissue site, and removal of the debris from the tissue site.

In some embodiments, the diameter of the orifices may be selected to permit flow of debris through the orifices and associated apertures. For example, in some embodiments the diameter of the orifices may be selected based on the size of the debris to be lifted from the tissue site. Generally, larger orifices may allow larger debris to pass through the contact layer and smaller orifices may allow smaller debris to pass through the contact layer while blocking debris larger than the orifices. In some embodiments, successive applications of a contact layer can progressively smaller diameters of the orifices. Sequentially decreasing diameters of the orifices may also aid in fine-tuning a level of tissue disruption to the debris during the treatment of the tissue site. The diameter of the orifices can also influence fluid movement in the contact layer.

The contact layer may be prepared for use by selecting a desired orifice size from either the apertures of the first diameter range or the second diameter range and configuring the contact layer such that orifices of the desired orifice size may be contacted with the tissue site. In some embodiments, such as the in the embodiments of <FIG>, <FIG>, configuring the contact layer may include orienting the contact layer such that the orifices of a desired size may be disposed adjacent to the tissue site. For example, a user may orient the contact layer such that the orifices having a diameter in a first range are in contact with the tissue or such that the orifices having a diameter in a second range are in contact with the tissue site.

Additionally or alternatively, in some embodiments such as the embodiment of <FIG>, configuring the contact layer may include determining whether to remove the removable portions of the contact or to leave the removable portions fitted within the contact layer. For example, if the user desires to use the orifices having a diameter in the first range, the user may leave the removable portions within the contact layer or, if the user desires to use the orifices having a diameter in the second range, the user may remove the removable portions from the contact layer.

Additionally or alternatively, in some embodiments such as the embodiment of <FIG>, configuring the contact layer may include placing the contact layer in a conformation in which the orifices of a desired size may be placed in contact with the tissue site. With the contact layer configured for placement, the contact layer may be placed within, over, on, or otherwise proximate to a tissue site.

Additionally or alternatively, in some embodiments configuring the contact layer may include separating a portion of contact layer, such as along a perforation, to form a desired size or shape. In some embodiments, a portion of a first contact layer may be placed over a first portion of a tissue site and a portion of a second contact layer may be placed over a second portion of the tissue site. For example, utilizing portions from difference contact layers to cover different portions of a tissue site may be effective to disrupt debris at a first portion of the tissue site while the second portion of the tissue site remains relatively undisrupted.

In some embodiments, a cover may be placed over the contact layer and sealed to an attachment surface near the tissue site. For example, the cover may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source can reduce the pressure in the sealed therapeutic environment. Negative pressure applied across the tissue site through the contact layer in the sealed therapeutic environment can induce macrostrain and microstrain in the tissue site, as well as remove exudates and other fluids from the tissue site, which can be collected in container.

In some embodiments, such as where the contact layer is employed to disrupt debris at a tissue site, the application of negative pressure to the tissue site via the contact layer can generate concentrated stresses in the debris adjacent and/or proximate to the apertures in the contact layer. The concentrated stresses can cause macro-deformations of the debris and the subcutaneous tissue, for example, which may draw portions of the debris and the subcutaneous tissue into the apertures. Similarly, the apertures of the contact layer may create macro-pressure points in portions of the debris and the subcutaneous tissue that are in contact with a tissue-facing surface of the contact layer, causing tissue puckering and nodules to be formed in the debris and the subcutaneous tissue. In some embodiments, formation of the nodules may lift debris and particulates off of the surrounding tissue, for example, operating in a piston-like manner to move debris toward and into the contact layer.

In various embodiments, a therapy system or components thereof, such as the contact layer, may be advantageously employed in the provision of therapy, such as negative pressure therapy, to a patient. For example, a contact layer configurable such that at least a portion of the apertures include a first plurality of orifices having a diameter in a first diameter range and such that at least a portion of the apertures include a second plurality of orifices having a diameter in a second diameter range may allow a user to choose an aperture size effective for obtaining desired results, such as the disruption of debris at the tissue site, in the context of the therapy. Thus, a single contact layer may be employed more effectively and efficiently across a wider variety of therapies.

Claim 1:
An apparatus (<NUM>) for treating a tissue site, the apparatus comprising:
a contact layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) formed from a compressible material, the contact layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising a first surface (<NUM>, <NUM>, <NUM>, <NUM>), a second surface (<NUM>, <NUM>, <NUM>, <NUM>), and a plurality of apertures (<NUM>, <NUM>, <NUM>) extending at least partially through the contact layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>),
at least a portion of the apertures (<NUM>, <NUM>, <NUM>) including a first plurality of orifices (<NUM>, <NUM>, <NUM>, <NUM>) in the first surface (<NUM>, <NUM>, <NUM>, <NUM>), each of the first plurality of orifices (<NUM>, <NUM>, <NUM>, <NUM>) having a diameter in a first diameter range, wherein the first diameter range is from about <NUM> to about <NUM>,
at least a portion of the apertures (<NUM>, <NUM>, <NUM>) including a second plurality of orifices (<NUM>, <NUM>, <NUM>, <NUM>) in the second surface (<NUM>, <NUM>, <NUM>, <NUM>), each of the second plurality of orifices (<NUM>, <NUM>, <NUM>, <NUM>) having a diameter in a second diameter range, wherein the second diameter range is from about <NUM> to about <NUM>;
a cover (<NUM>) configured to form a sealed space including the contact layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the tissue site, and
a reduced-pressure source (<NUM>) adapted to apply a reduced pressure to the sealed space,
wherein, in use, either the first surface (<NUM>, <NUM>, <NUM>, <NUM>) or the second surface (<NUM>, <NUM>, <NUM>, <NUM>) of the contact layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) contacts the tissue site.