Negative pressure wound therapy dressing with slit foam layer

Abstract

Apparatus, dressings, systems, and methods for treating a tissue site with negative pressure. The dressing includes a cover and a tissue interface including a manifold and a film layer. The manifold includes a plurality of slits. The plurality of slits includes a first sidewall and a second sidewall that are deformable between a closed state and an open state. The film layer includes a plurality of fenestrations through the first and second surfaces of the film layer that align with the plurality of slits in the foam.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Application No. 63 / 291,280, filed December 17, 2021, which is incorporated herein by reference in its entirety.

[0002] The present invention as claimed in the appended claims relates generally to tissue treatment systems and more particularly, but not by way of limitation, to negative pressure wound therapy dressings that include a slit foam layer. [Background technology]

[0003] Clinical studies and clinical practice have shown that reducing pressure near a tissue site can enhance and accelerate the growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but have proven particularly advantageous for treating wounds. Regardless of the etiology of the wound, whether trauma, surgery, or another cause, proper care of the wound is important to the outcome. Treatment of wounds or other tissues with reduced pressure may be commonly referred to as "negative pressure therapy," but is also known by other names, including, for example, "negative pressure wound therapy," "reduced pressure therapy," "vacuum therapy," "vacuum-assisted closure," and "topical negative pressure." Negative pressure therapy may provide many benefits, including epithelial and subcutaneous tissue migration, improved blood flow, and microdeformation of tissue at the wound site. Overall, these benefits can enhance granulation tissue development and reduce healing time.

[0004] While the clinical benefits of negative pressure therapy are widely known, improvements in therapy systems, components, and processes can benefit healthcare providers and patients. Summary of the Invention

[0005] The appended claims describe new and useful systems, devices, and methods for negative pressure wound therapy dressings including a slit foam layer in a negative pressure therapy environment. Exemplary embodiments are also provided to enable one of ordinary skill in the art to make and use the claimed subject matter.

[0006] In some exemplary embodiments, a dressing for treating a tissue site with negative pressure is described. The dressing can include a cover, a manifold including a foam, and a film layer. The cover can include a first surface and a second surface. The manifold can include a first surface, a second surface, and a plurality of slits. The first surface of the manifold can be adjacent to the second surface of the cover. The plurality of slits can include a first sidewall and a second sidewall extending between the first surface and the second surface of the manifold that are deformable between a closed state and an open state. The first sidewall can contact the second sidewall in the closed state and can be separated from the second sidewall in the open state. The film layer can include a first surface, a second surface, and a plurality of fenestrations through the first surface and the second surface. The first surface of the film layer can be adjacent to the second surface of the manifold.

[0007] In some exemplary embodiments, the plurality of slits of the manifold are configured to transform from a closed state to an open state when the dressing is exposed to a negative pressure, an axial force, or a bending moment. The plurality of slits can define a slit opening through the foam between the first sidewall and the second sidewall in the open state. The plurality of slits can include a linear cut having a length. The first sidewall can be positioned on an opposite side of the linear cut from the second sidewall. For example, the first sidewall can be positioned opposite the second sidewall across the entire slit opening of each of the plurality of slits.

[0008] In some exemplary embodiments, one or more of the plurality of slits are deformable between a closed state and an open state independently of another of the plurality of slits. The plurality of fenestrations in the film layer may be configured to deform in alignment with the plurality of slits in the manifold when the dressing is exposed to negative pressure. More generally, the plurality of fenestrations in the film layer and the plurality of slits in the manifold are aligned in both the open and closed states and are configured to deform in concert in response to negative pressure. In some exemplary embodiments, the plurality of fenestrations may each comprise a periphery that may be positioned flush with a first sidewall and a second sidewall of the plurality of slits. In some embodiments, the plurality of fenestrations and the plurality of slits may have the same shape.

[0009] In some exemplary embodiments, the dressing may further comprise a base layer adjacent the second surface of the film layer. The base layer may include a central portion having a base layer opening and a peripheral portion including a plurality of gaps. The peripheral portion may surround the central portion, and the plurality of gaps in the peripheral portion may be smaller than the base layer opening in the central portion. The base layer opening may be a single opening and may surround at least 90 percent of the plurality of fenestrations in the film layer. The plurality of fenestrations and at least a portion of the film layer may be exposed through the base layer opening. For example, the film layer may be configured to contact the tissue site through the base layer opening, and the peripheral portion of the base layer may be configured to contact tissue surrounding the tissue site. In some exemplary embodiments, the film layer may include a central portion including a plurality of fenestrations aligned with the foam, and a peripheral portion including a plurality of perforations extending beyond the foam and surrounding the plurality of fenestrations.

[0010] In some exemplary embodiments, the cover can include a periphery having adhesive extending beyond the manifold. The periphery of the cover can be configured to encapsulate the manifold between the base layer and the cover. The peripheral adhesive can be configured to extend through a plurality of gaps in the base layer to contact tissue surrounding the tissue site. The dressing can further include at least one handling bar configured to add rigidity to a portion of the dressing to enable a user to place the dressing at the tissue site.

[0011] Also described herein is a system for treating a tissue site with negative pressure. An illustrative example of the system can include a dressing and a negative pressure source that can be fluidly coupled to the dressing. The dressing can include a cover, a manifold including a foam, and a film layer. The cover can include a first surface and a second surface. The manifold can include a first surface, a second surface, and a plurality of slits. The first surface of the manifold can be adjacent to the second surface of the cover. The plurality of slits can include a first sidewall and a second sidewall extending between the first surface and the second surface of the manifold that are deformable between a closed state and an open state. The first sidewall can contact the second sidewall in the closed state and can be separated from the second sidewall in the open state. The film layer can include a first surface, a second surface, and a plurality of fenestrations through the first surface and the second surface. The first surface of the film layer can be adjacent to the second surface of the manifold.

[0012] Also described herein is a tissue interface for treating a tissue site with negative pressure. An illustrative example of a tissue interface can include a manifold layer and a film layer. The manifold layer can include a plurality of slits, each of the plurality of slits including a first sidewall and a second sidewall. The film layer can be bonded to a surface of the manifold layer and can include a plurality of fenestrations. Each of the plurality of fenestrations can include a periphery positioned flush with the first sidewall and the second sidewall of the plurality of slits.

[0013] Also described herein are methods of treating a tissue site. An illustrative example of the method can include applying a dressing to the tissue site, fluidly coupling a negative pressure source to the dressing, and activating the negative pressure source to apply negative pressure to the dressing. The dressing can include a foam having a plurality of slits and a film layer positioned between the foam and the tissue site. The film layer can include a plurality of fenestrations configured to align with the plurality of slits in the foam. When activating the negative pressure source to apply negative pressure to the dressing, the plurality of slits in the foam can deform in coordination with the plurality of fenestrations in the film layer when negative pressure is applied to the dressing.

[0014] The objects, advantages and preferred modes of making and using the claimed subject matter may best be understood by reference to the following detailed description of exemplary embodiments in conjunction with the accompanying drawings, in which: [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a block diagram of one exemplary embodiment of a therapy system capable of providing negative pressure treatment in accordance with the present disclosure. [Diagram 2] 2 is a cutaway view of an exemplary embodiment of the therapy system of FIG. 1 showing an exemplary embodiment of the dressing interface and a dressing deployed at a tissue site. [Diagram 3]FIG. 3 is an exploded view of the dressing of FIG. 2 shown with an illustrative example embodiment of a release liner for protecting the dressing prior to application to a tissue site. [Figure 4] FIG. 4 is a cutaway view of the dressing of FIG. [Diagram 5] 5 is a perspective view of an illustrative example embodiment of the manifold and film layers shown in the dressing of FIG. 2. [Figure 6A] 6A is a perspective view of another illustrative example embodiment of a manifold that may be used with the dressing of FIG. 2. FIG. [Figure 6B] FIG. 6B is a perspective view of the manifold of FIG. 6A when a force is applied to the manifold. [Figure 6C] FIG. 6C is a perspective view of the manifold of FIG. 6A when a force is applied to the manifold. [Figure 6D] FIG. 6D is a perspective view of the manifold of FIG. 6A when a force is applied to the manifold. [Figure 7] FIG. 7 is an exploded view of another illustrative example embodiment of a dressing that may be used with the therapy system of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The following description of exemplary embodiments provides information to enable one of ordinary skill in the art to make and use the subject matter recited in the appended claims, but may omit certain details that are already well known in the art. Thus, the following detailed description is to be construed as illustrative and not limiting.

[0017] FIG. 1 is a block diagram of an exemplary embodiment of a therapy system 100 capable of providing negative pressure therapy to a tissue site in accordance with the present disclosure.

[0018] The term "tissue site" in this context refers broadly to a wound, defect, or other therapeutic target located on or within tissue, including, but not limited to, bone tissue, adipose tissue, muscle tissue, nerve tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendon, or ligament. Wounds may include, for example, chronic, acute, traumatic, subacute, and dehisced wounds, partial thickness burns, ulcers (such as diabetic ulcers, pressure ulcers, or venous insufficiency ulcers), skin flaps, and grafts. The term "tissue site" may also refer to an area of ​​any tissue that is not necessarily wounded or defective, but instead is an area where it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be applied to the tissue site to grow additional tissue that can be harvested and transplanted.

[0019] 1, therapy system 100 can include a negative pressure source or supply, such as negative pressure source 105, and one or more distribution components. The distribution components are preferably separable and can be disposable, reusable, or recyclable. Dressings, such as dressing 110, and fluid containers, such as container 115, are examples of distribution components that can be associated with some examples of therapy system 100. As illustrated in the example of FIG. 1, dressing 110 can comprise or consist essentially of tissue interface 120, cover 125, or both in some embodiments.

[0020] A fluid conduit is another illustrative example of a distribution component. A "fluid conduit" in this context broadly includes a tube, pipe, hose, conduit, or other structure having one or more lumens or open pathways adapted to transport fluid between two ends. Typically, a tube is an elongated cylindrical structure with some flexibility, but the geometry and stiffness may vary. Additionally, some fluid conduits may be molded into or otherwise integrally combined with other components. A distribution component may also include or comprise an interface or fluid port to facilitate coupling and decoupling of other components. In some embodiments, for example, a dressing interface may facilitate coupling of the fluid conduit to the dressing 110. For example, such a dressing interface may be a SENSAT.RAC™ Pad available from Kinetic Concepts, Inc. (San Antonio, Texas).

[0021] Therapy system 100 may also include a controller, such as regulator or controller 130. In addition, therapy system 100 may include sensors for measuring operating parameters and providing feedback signals indicative of the operating parameters to controller 130. As illustrated in FIG. 1, for example, therapy system 100 may include a first sensor 135 and a second sensor 140 coupled to controller 130.

[0022] Some components of therapy system 100 may be contained 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, negative pressure source 105 may be combined into a therapy unit 145 along with controller 130 and other components.

[0023] In general, the components of the therapy system 100 may be coupled directly or indirectly. For example, the negative pressure source 105 may be directly coupled to the container 115 and indirectly coupled to the dressing 110 through the container 115. In some contexts, coupling may include fluid coupling, mechanical coupling, thermal coupling, electrical coupling, or chemical coupling (such as chemical bonding), or some combination. For example, the negative pressure source 105 may be electrically coupled to the controller 130 and fluidly coupled to one or more distribution components to provide a fluid pathway to the tissue site. In some embodiments, components may also be coupled by physical proximity, by integration into a single structure, or by being formed from the same piece of material.

[0024] A negative pressure source such as negative pressure source 105 may be, for example, a reservoir of air at negative pressure, or may be a manually or electrically driven device such as a vacuum pump, suction pump, wall suction port available in many medical facilities, or a micropump. "Negative pressure" generally refers to a pressure less than the local ambient pressure, such as the ambient pressure in the local external environment to the sealed treatment environment. In many cases, the local ambient pressure may also be atmospheric pressure where the tissue site is located. Alternatively, the pressure may be less than the hydrostatic pressure associated with the tissue at the tissue site. Unless otherwise indicated, the pressure values ​​described herein are gauge pressures. References to increasing negative pressure typically refer to decreasing absolute pressure, while decreasing negative pressure typically refers to increasing absolute pressure. While the amount and nature of negative pressure provided by negative pressure source 105 may vary according to treatment requirements, the pressure is generally a low vacuum, commonly also referred to as a rough vacuum, of between -5 mmHg (-667 Pa) and -500 mmHg (-66.7 kPa). A typical treatment range is -50mmHg (-6.7kPa) to -300mmHg (-39.9kPa).

[0025] Container 115 represents a container, canister, pouch, or other storage component that can be used to manage exudate and other fluids removed from a tissue site. In many circumstances, a rigid container may be preferred or necessary to collect, store, and discard fluids. In other circumstances, fluids may be properly discarded without being stored in a rigid container, but a reusable container can reduce waste and costs associated with negative pressure therapy.

[0026] A controller, such as controller 130, may be a microprocessor or computer programmed to operate one or more components, such as negative pressure source 105, of therapy system 100. In some embodiments, for example, controller 130 may be a microcontroller, which generally comprises an integrated circuit including a processor core and memory, programmed to directly or indirectly control one or more operating parameters of therapy system 100. The operating parameters may include, for example, the power applied to negative pressure source 105, the pressure generated by negative pressure source 105, or the pressure delivered to tissue interface 120. Controller 130 is also preferably configured to receive one or more input signals, such as a feedback signal, and is programmed to modify one or more operating parameters based on the input signals.

[0027] Sensors, such as the first sensor 135 and the second sensor 140, may be devices operable to detect or measure a physical phenomenon or characteristic and generally provide a signal indicative of the detected or measured phenomenon or characteristic. For example, the first sensor 135 and the second sensor 140 may be configured to measure one or more operating parameters of the therapy system 100. In some embodiments, the first sensor 135 may be a transducer configured to measure the pressure of the pneumatic path and convert the measurement into a signal indicative of the measured pressure. In some embodiments, for example, the first sensor 135 may be a piezoresistive strain gauge. In some embodiments, the second sensor 140 may optionally measure an operating parameter of the negative pressure source 105, such as a voltage or current. The signals from the first sensor 135 and the second sensor 140 may be suitable as input signals to the controller 130, although in some embodiments some signal conditioning may be appropriate. For example, the signals may need to be filtered or amplified before they can be processed by the controller 130. Typically the signals are electrical signals, but may be represented in other forms, such as optical signals.

[0028] The tissue interface 120 may generally be adapted to partially or completely contact a tissue site. The tissue interface 120 may take many forms and may have many sizes, shapes, or thicknesses depending on various factors, such as the type of treatment being performed or the nature and size of the tissue site. For example, the size and shape of the tissue interface 120 may be adapted to the contours of a deep, irregularly shaped tissue site. Any or all of the surfaces of the tissue interface 120 may have an undulating, rough, or jagged profile.

[0029] The thickness of the tissue interface 120 may also vary according to the needs of the indicated therapy. For example, the thickness of the tissue interface may be reduced to reduce tension on the surrounding tissue. The thickness of the tissue interface 120 may also affect the conformability of the tissue interface 120. In some embodiments, a thickness in the range of about 5 millimeters to 10 millimeters may be appropriate.

[0030] In some embodiments, the cover 125 may provide a bacterial barrier and protection from physical trauma. The cover 125 may also be constructed from a material that can reduce evaporative loss and provide a fluid seal between two components or between two environments, such as between a treatment environment and a local external environment. The cover 125 may include or consist of, for example, an elastic film or membrane that can provide a sufficient seal to maintain a negative pressure at a tissue site for a given negative pressure source. In some applications, the cover 125 may have a high moisture-vapor transmission rate (MVTR). For example, the MVTR may be, in some embodiments, at least 250 grams per square meter per 24 hours when measured using an upright cup technique according to the Upright Cup Method of ASTM E96 / E96M at 38° C. and 10% relative humidity (RH). In some embodiments, an MVTR of up to 5000 grams per square meter per 24 hours may provide effective breathability and mechanical properties.

[0031] In some exemplary embodiments, the cover 125 may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquids. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability should generally be low enough so that the desired negative pressure can be maintained. The cover 125 may include, for example, one or more of polyurethanes (PU), such as hydrophilic polyurethanes; cellulose derivatives; hydrophilic polyamides; polyvinyl alcohols; polyvinylpyrrolidones; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubbers; polyisoprene; styrene butadiene rubbers; chloroprene rubbers; polybutadiene; nitrile rubbers; butyl rubbers; ethylene propylene rubbers; ethylene propylene diene monomers; chlorosulfonated polyethylenes; polysulfide rubbers; ethylene vinyl acetates (EVA); copolyesters; and polyether block polyamide copolymers. Such materials are commercially available, for example, Tegaderm® drapes available from 3M Company (Minneapolis, Minnesota), polyurethane (PU) drapes available from Avery Dennison Corporation (Pasadena, California), such as polyether block polyamide copolymer (PEBAX) from Arkema SA (Colombes, France), and Inspire 2301 and Inspire 2327 polyurethane films available from Expopack Advanced Coatings (Wrexham, United Kingdom). In some embodiments, the cover 125 is 2600 g / m 2 / INSPIRE2301 having a 24 hour MVTR (Upright Cup Technology) and a thickness of approximately 30 microns.

[0032] An attachment device may be used to attach the cover 125 to an attachment surface, such as an intact epidermis, a gasket, or another cover. The attachment device may take many forms. For example, the attachment device may be a medically acceptable pressure sensitive adhesive configured to bond the cover 125 to the epidermis around the tissue site. In some embodiments, for example, part or all of the cover 125 may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight of about 25 to 65 grams per square meter (gsm). In some embodiments, a thicker adhesive, or combination of adhesives, may be applied to improve the seal and reduce leakage. Other exemplary embodiments of the attachment device may include a double-sided tape, a paste, a hydrocolloid, a hydrogel, a silicone gel, or an organogel.

[0033] In operation, the tissue interface 120 may be disposed within, over, on, or otherwise proximate to the tissue site. For example, if the tissue site is a wound, the tissue interface 120 may partially or completely occlude or be disposed over the wound. The cover 125 may be disposed over the tissue interface 120 and sealed to an attachment surface proximate the tissue site. For example, the cover 125 may be sealed to the tissue site about an intact epidermis. Thus, the dressing 110 may provide a sealed treatment environment proximate to the tissue site that is substantially isolated from the external environment, and the negative pressure source 105 may reduce pressure within the sealed treatment environment.

[0034] The process of reducing pressure may be illustratively described herein as, for example, "delivering," "distributing," or "generating" negative pressure. In general, exudates and other fluids flow along a fluid pathway toward a lower pressure. Thus, the term "downstream" typically refers to a position in the fluid pathway that is relatively closer to a negative pressure source or farther away from a positive pressure source. Conversely, the term "upstream" refers to a position relatively farther away from a negative pressure source or closer to a positive pressure source. However, the fluid pathway may also be reversed in some applications, such as by replacing a negative pressure source with a positive pressure source, and thus these descriptive terms should not be construed as limiting.

[0035] Negative pressure applied to the tissue site through the tissue interface 120 within the sealed treatment environment can induce macro- and micro-strains at the tissue site. The negative pressure can also remove exudate and other fluids from the tissue site, which can be collected in the container 115.

[0036] In some embodiments, the controller 130 may receive and process data from one or more sensors, such as the first sensor 135. The controller 130 may also control the operation of one or more components of the therapy system 100 to manage the pressure delivered to the tissue interface 120. In some embodiments, the controller 130 may include an input for receiving a desired target pressure and may be programmed to process data regarding the setting and input of the target pressure to be applied to the tissue interface 120. In some exemplary embodiments, the target pressure may be a fixed pressure value that is set by an operator as the target negative pressure desired for therapy at the tissue site and then provided as an input to the controller 130. The target pressure may vary from tissue site to tissue site based on the type of tissue forming the tissue site, the type of injury or wound (if any), the medical condition of the patient, and the preferences of the attending physician. After selecting the desired target pressure, the controller 130 may operate the negative pressure source 105 in one or more control modes based on the target pressure and may receive feedback from one or more sensors to maintain the target pressure at the tissue interface 120.

[0037] FIG. 2 illustrates an exemplary embodiment of a therapy system 100 for treating a tissue site 202 of a patient. The tissue site 202 may extend through or otherwise include the epidermis 204, the dermis 206, and the subcutaneous tissue 208. The tissue site 202 may be a subsurface tissue site depicted in FIG. 2 that extends below the surface of the epidermis 204. Additionally, the tissue site 202 may be a superficial tissue site (not shown) that resides primarily on the surface of the epidermis 204, such as an incision. The therapy system 100 may provide therapy to the epidermis 204, the dermis 206, and the subcutaneous tissue 208, for example, regardless of the positioning of the therapy system 100 or the type of tissue site. The therapy system 100 may also be utilized at other tissue sites, including but not limited to.

[0038] Therapy system 100 may include dressing 110, reservoir 115, and negative pressure source 105, which may include therapy unit 145. Additionally, therapy system 100 may include filler material 210 as an optional component of therapy system 100. Filler material 210 may be omitted for different types of tissue sites or different types of therapies using negative pressure, such as epithelialization. If provided, filler material 210 may be adapted to be positioned adjacent or proximate to tissue site 202, such as by cutting or otherwise shaping filler material 210 in any suitable manner to fit tissue site 202 and fill the space between tissue site 202 and dressing 110. Similar to tissue interface 120, filler material 210 may be constructed of manifold materials described herein and adapted to be positioned in fluid communication with tissue site 202 to distribute negative pressure to tissue site 202. In some embodiments, the filler material 210 may be positioned in direct contact with the tissue site 202 and between the tissue site 202 and the dressing 110. If the filler material 210 is omitted, the tissue interface 120 of the dressing 110 may be positioned in direct contact with the tissue site 202.

[0039] Continuing with FIG. 2, the dressing 110 may be adapted to provide or distribute negative pressure from the negative pressure source 105 of the therapy unit 145 to the tissue site 202, either directly or through the filler material 210, if equipped. Further, FIG. 2 illustrates additional features that may be associated with some exemplary embodiments of the tissue interface 120 of the dressing 110. For example, the tissue interface 120 of the dressing 110 may include an optional base layer 212, a film layer 214, and a manifold 216. The manifold 216 may be or include a foam and may be referred to as a manifold layer. An adhesive layer, such as adhesive 218, may be configured to be positioned between the cover 125 and the periphery of the tissue site 202 to secure the dressing 110 to the tissue site 202. Components of the dressing 110 may be added or removed for a particular application.

[0040] 2-4, the base layer 212 can have a perimeter 220 surrounding the central portion 222 and a plurality of gaps 224 disposed through the perimeter 220. The base layer 212 can also have corners 226 and edges 228. The corners 226 and edges 228 can be part of the perimeter 220. One of the edges 228 can combine with another of the edges 228 to define one of the corners 226. Additionally, the base layer 212 can have a boundary 230 that substantially surrounds the central portion 222 and is positioned between the central portion 222 and the perimeter 220. The boundary 230 can be free of gaps 224 and can surround a base layer opening 232 through the central portion 222 of the base layer 212. The base layer opening 232 can be a single opening and can prevent the base layer 212 from contacting the tissue site 202. Each gap 224 in the plurality of gaps 224 can be smaller than the base layer opening 232. The base layer 212 can be coupled to tissue surrounding the tissue site 202 such that the base layer opening 232 in the central portion 222 of the base layer 212 is positioned adjacent or proximate to the tissue site 202 and the periphery 220 of the base layer 212 is positioned adjacent or proximate to the tissue surrounding the tissue site 202. In this manner, the periphery 220 of the base layer 212 can surround the tissue site 202.

[0041] The gaps 224 in the base layer 212 may have another shape, such as, for example, a circle, a square, a star, an oval, a polygon, a slit, a compound curve, a straight line, a triangle, or other shape. The gaps 224 may be formed by cutting, applying localized RF energy, or other suitable techniques for forming openings. As shown in FIG. 3, each gap 224 of the plurality of gaps 224 may be substantially circular in shape having a diameter and an area. The area of ​​each of the gaps 224 may refer to the open space or open area that defines each of the gaps 224. The diameter of each of the gaps 224 may define the area of ​​each of the gaps 224. For example, the area of ​​one of the gaps 224 may be defined by multiplying half the diameter of the gap 224 by the value 3.14. Thus, the following formula may define the area of ​​one of the gaps 224: Area=3.14×(Diameter / 2)^2. The area of ​​the gaps 224 described in the exemplary embodiments herein may be substantially similar to the area (not shown) in other embodiments of gaps 224 that may have a non-circular shape. The diameter of each of the gaps 224 may be substantially the same, or each of the diameters may vary depending, for example, on the location of the gap 224 within the base layer 212. Further, the diameter of each of the gaps 224 may be from about 1 millimeter to about 50 millimeters. In some embodiments, the diameter of each of the gaps 224 may be from about 1 millimeter to about 20 millimeters. The gaps 224 may have a uniform pattern or may be randomly distributed in the base layer 212. The size and configuration of the gaps 224 may be designed to control the adhesion of the dressing 110 to the epidermis 204, as described below.

[0042] As described herein, the base layer 212 may be a pliable, soft material suitable for providing a fluid seal with the tissue site 202. For example, the base layer 212 may include silicone gel, soft silicone, hydrocolloid, hydrogel, polyurethane gel, polyolefin gel, hydrogenated styrene copolymer gel, foam gel, soft closed cell foam such as polyurethane and polyolefin coated with adhesives described below, polyurethane, polyolefin, or hydrogenated styrene copolymer. In some embodiments, the base layer 212 may be a tri-laminate material including a film layer, a silicone gel bonded to a surface of the film layer proximate the tissue site 202, and an adhesive layer bonded to a surface of the film layer opposite the silicone gel. The base layer 212 may have a thickness of about 500 microns (μm) to about 1000 microns (μm). In some embodiments, the base layer 212 has a stiffness of about 5 Shore OO to about 90 Shore OO. The base layer 212 may be made of a hydrophobic or hydrophilic material.

[0043] In some embodiments (not shown), the base layer 212 can be a hydrophobically coated material. For example, the base layer 212 can be formed by coating a spacing material, such as, for example, a woven mesh, a nonwoven mesh, a molded mesh, or an extruded mesh, with a hydrophobic material. The hydrophobic material for the coating can be, for example, a soft silicone. In this manner, the adhesive 218 can extend through openings in the spacing material similar to the gaps 224 described below.

[0044] The adhesive 218 may be in fluid communication with the gaps 224 at least at the periphery 220 of the base layer 212. In this manner, the adhesive 218 may be in fluid communication with the tissue surrounding the tissue site 202 through the gaps 224 of the base layer 212. As described below, the adhesive 218 may extend or be forced through the multiple gaps 224 to contact the epidermis 204, for example, to secure the dressing 110 to the tissue surrounding the tissue site 202. The gaps 224 may provide sufficient contact of the adhesive 218 to the epidermis 204 to secure the dressing 110 about the tissue site 202. However, the configuration of the gaps 224 and adhesive 218 may allow for release and repositioning of the dressing 110 about the tissue site 202.

[0045] The adhesive 218 may be a medically acceptable adhesive. The adhesive 218 may also be flowable. For example, the adhesive 218 may include an acrylic adhesive, a rubber adhesive, a high tack silicone adhesive, a polyurethane, or other adhesive substance. In some embodiments, the adhesive 218 has a viscosity of 15 grams / m 2 (gsm) ~70 grams / m 2The adhesive 218 may be a pressure sensitive adhesive including an acrylic adhesive having a coating weight of 100 gsm. The adhesive 218 may be a layer having openings 234. The openings 234 in the adhesive 218 may ensure that the adhesive 218 does not contact the central portion 222 of the base layer 212. The openings 234 may be rectangular as shown in FIG. 3. In other embodiments, the openings 234 may be a different size or shape but still isolate the adhesive 218 from the central portion 222 of the base layer 212. In some embodiments, the layer of adhesive 218 may be continuous or discontinuous. The discontinuities in the adhesive 218 may be provided by gaps (not shown) in the adhesive 218. The gaps in the adhesive 218 may be formed after application of the adhesive 218 or by coating the adhesive 218 in a pattern onto a carrier layer, such as the side of the cover 125 adapted to face the epidermis 204. Additionally, the gaps in the adhesive 218 may be sized to control the amount of adhesive 218 that extends through the gaps 224 in the base layer 212 to reach the epidermis 204. The gaps in the adhesive 218 may also be sized to increase the Moisture Vapor Transfer Rate (MVTR) of the dressing 110.

[0046] Factors that may be utilized to control the adhesive strength of the dressing 110 may include the diameter and number of gaps 224 in the base layer 212, the thickness of the base layer 212, the thickness and amount of adhesive 218, and the viscosity of the adhesive 218. An increase in the amount of adhesive 218 extending through the gaps 224 generally corresponds to an increase in the adhesive strength of the dressing 110. A decrease in the thickness of the base layer 212 generally corresponds to an increase in the amount of adhesive 218 extending through the gaps 224. Thus, the diameter and configuration of the gaps 224, the thickness of the base layer 212, and the amount and viscosity of adhesive utilized may be varied to provide a desired adhesive strength of the dressing 110. For example, the thickness of the base layer 212 may be approximately 200 microns, the layer of adhesive 218 may have a thickness of approximately 30 microns and a viscosity of 2000 grams per 25 centimeter wide strip, and the diameter of the gaps 224 in the base layer 212 may be approximately 10 millimeters.

[0047] In some embodiments, the tackiness of the adhesive 218 may vary at different locations on the base layer 212. For example, some of the gaps 224 of the base layer 212 may be larger than other gaps 224 of the base layer 212. For example, in some embodiments, the gaps 224 at the corners 226 of the base layer 212 may be smaller than the gaps 224 along the edges 228 of the base layer 212. In locations of the base layer 212 where the gaps 224 are relatively larger, the adhesive 218 may have a lower tackiness than other locations of the base layer 212 where the gaps 224 are smaller. In this manner, locations of the base layer 212 with larger gaps 224 and adhesive 218 with less tackiness may have similar adhesive strength as locations with smaller gaps 224 and adhesive 218 with more tackiness.

[0048] Clinical studies have shown that the configurations described herein for the base layer 212 and adhesive 218 may reduce the occurrence of blistering, erythema, and leakage during use. Such configurations may provide, for example, improved patient comfort and improved durability of the dressing 110.

[0049] 3 , the release liner 236 may be attached or positioned adjacent to the base layer 212 to protect the adhesive 218 prior to application of the dressing 110 to the tissue site 202. In some embodiments, the release liner 236 may be a one-piece liner. In other embodiments, the release liner 236 may be a two-piece liner with an overlap to ensure that the base layer 212 is covered by the release liner 236 prior to deployment of the dressing 110 at the tissue site 202. The base layer 212 may be positioned between the cover 125 and the release liner 236 prior to application of the dressing 110 to the tissue site 202. Removal of the release liner 236 may expose the base layer 212 and adhesive 218 for application of the dressing 110 to the tissue site 202. The release liner 236 may also provide stiffness to aid in deployment of the dressing 110, for example. The release liner 236 may be, for example, a process paper, film, or polyethylene. Additionally, the release liner 236 may be a polyester material, such as polyethylene terephthalate (PET) or a similar polar semi-crystalline polymer. The use of a polar semi-crystalline polymer for the release liner 236 may substantially eliminate wrinkling or other deformation of the dressing 110. For example, the polar semi-crystalline polymer may be highly oriented and resistant to softening, swelling, or other deformation that may occur when in contact with components of the dressing 110, or when subjected to temperature or environmental changes, or when subjected to sterilization. Additionally, a release agent may be disposed on the side of the release liner 236 that is configured to contact the base layer 212. For example, the release agent may be a silicone coating and may have release elements suitable for facilitating removal of the release liner 236 by hand without damaging or deforming the dressing 110. In some embodiments, the release agent may be a fluorosilicone. In other embodiments, the release liner 236 may be uncoated or may otherwise be used without a release agent.

[0050] Continuing with FIGS. 2-4, the cover 125 may be substantially as described above with reference to FIG. 1. The cover 125 may have a perimeter or periphery 238 and a central portion 240. The cover 125 may also have a first surface 242 and a second surface 244 opposite the first surface 242. The cover 125 may further include a gap 246. The gap 246 may be an opening or hole through the cover 125. In some embodiments, the gap 246 may be located such that it is substantially central to the cover 125. The gap 246 may be configured to allow fluid communication from the first surface 242 of the cover 125 through the dressing 110. The periphery 238 of the cover 125 may be positioned proximate the periphery 220 of the base layer 212, and the central portion 240 of the cover 125 may be substantially aligned with the central portion 222 of the base layer 212.

[0051] The adhesive 218 may be positioned at least between the perimeter 238 of the cover 125 and the perimeter 220 of the base layer 212. The cover 125 may cover the tissue site 202 and the tissue interface 120 to provide a fluid seal and a sealed space 248 between the tissue site 202 and the cover 125 of the dressing 110. Additionally, the cover 125 may cover other tissue, such as a portion of the epidermis 204 surrounding the tissue site 202, to provide a fluid seal between the cover 125 and the tissue site 202. In some embodiments, a portion of the perimeter 238 of the cover 125 may extend beyond the perimeter 220 of the base layer 212 to directly contact the tissue surrounding the tissue site 202. In other embodiments, the perimeter 238 of the cover 125 may be positioned in contact with the tissue surrounding the tissue site 202 to provide a sealed space 248, for example, free of the base layer 212. Thus, the adhesive 218 may also be positioned at least between the periphery 238 of the cover 125 and tissue, such as the epidermis 204, surrounding the tissue site 202. The adhesive 218 may be disposed on a surface of the cover 125 adapted to face the tissue site 202 and the base layer 212.

[0052] The manifold 216 may be positioned between the cover 125 and the film layer 214. The manifold 216 may have a first surface 250 and a second surface 252 opposite the first surface 250. The manifold 216 may comprise, or consist essentially of, a means for distributing fluid to the tissue site 202. For example, the manifold 216 may be adapted to receive negative pressure from the negative pressure source 105 and distribute the negative pressure through the manifold 216, which may have the effect of withdrawing fluid from the tissue site 202 and sucking the fluid towards the negative pressure source 105. The manifold 216 may further include a plurality of slits 254 disposed through the manifold 216 from the first surface 250 to the second surface 252. The plurality of slits 254 may be configured to aid in distributing the negative pressure through the manifold 216. In some embodiments, the multiple slits 254 may allow for relatively even distribution of negative pressure through the manifold 216 to the tissue site 202 while reducing the likelihood of tissue ingrowth from the tissue site 202 into the dressing 110.

[0053] Each slit 254 of the plurality of slits 254 may comprise a linear slit or linear cut 255 that extends from the first surface 250 of the manifold 216 to the second surface 252 of the manifold 216. In other embodiments, the plurality of slits 254 may be a different shape but still extend from the first surface 250 of the manifold 216 to the second surface 252 of the manifold 216. The plurality of slits 254 may be formed by cutting, application of localized RF energy, die cutting, knife cutting, discontinuous slit machining, or other suitable techniques for forming slits through the manifold 216. As defined herein, the slits or cuts that form the slits 254 may be distinguished from gaps or other openings in that a portion of material on either side of the slit 254 is separated or cut without removing material to form the slit 254. Thus, the plurality of slits 254 can include a first sidewall 256 and a second sidewall 258, both of which can extend between the first surface 250 and the second surface 252 of the manifold 216. The first sidewall 256 can be positioned on an opposite side of the linear cut 255 from the second sidewall 258.

[0054] The first sidewall 256 and the second sidewall 258 may be deformable between a closed state and an open state. In a closed state where the manifold 216 is relaxed or not under stress, the first sidewall 256 may contact the second sidewall 258. In an open state where the manifold 216 is under stress or force, the first sidewall 256 may be separated from the second sidewall 258. In some embodiments, the plurality of slits 254 may be deformable or movable from a closed state to an open state when the dressing 110 is exposed to a negative pressure, such as negative pressure from the negative pressure source 105. In other embodiments, the plurality of slits 254 may be deformable or movable from a closed state to an open state when the dressing 110 is exposed to a force or bending moment. Each slit 254 of the plurality of slits 254 may be deformable or movable between a closed state and an open state independently of another slit 254 of the plurality of slits 254.

[0055] In some exemplary embodiments, the manifold 216 may include multiple passages that may be interconnected to improve fluid distribution or recovery. In some exemplary embodiments, the manifold 216 may include, or consist essentially of, a porous material having interconnected fluid pathways. Examples of suitable porous materials that may be adapted to form interconnected fluid pathways (e.g., channels) include cellular foams, including open-cell foams such as reticulated foams, porous tissue aggregates, and other porous materials such as gauze or felt-like mats that generally include pores, edges, and / or walls. Liquids, gels, and other foams may also include or be hardened to include interstices and fluid pathways. In some embodiments, the manifold 216 may additionally or alternatively include protrusions that form the interconnected fluid pathways. For example, the manifold 216 may be molded to provide surface protrusions that define the interconnected fluid pathways.

[0056] In some embodiments, the manifold 216 may include or consist essentially of a foam, such as a reticulated foam, with pore size and free volume that may vary according to the needs of the indicated therapy. For example, a reticulated foam with at least 90% free volume may be suitable for many therapy applications, and foams with average pore sizes in the range of 400-600 microns (40-50 pores per inch) may be particularly suitable for some types of therapy. The tensile strength of the manifold 216 may also vary according to the needs of the indicated therapy. The 25% compressive load deflection of the manifold 216 may be at least 0.35 pounds per square inch, and the 65% compressive load deflection may be at least 0.43 pounds per square inch. In some embodiments, the tensile strength of the manifold 216 may be at least 10 pounds per square inch. The manifold 216 may have a tear strength of at least 2.5 pounds per square inch. In some embodiments, the manifold 216 can be a foam comprised of a polyol, such as a polyester or polyether, an isocyanate, such as toluene diisocyanate, and a polymerization modifier, such as an amine and tin compound. In some examples, the manifold 216 can be a reticulated polyurethane foam, such as found in GRANUFOAM™ dressings or VACVERAFLO™ dressings, both available from Kinetic Concepts, Inc. (San Antonio, Texas). In other embodiments, the manifold can be a laminate of one or more of a thermoplastic polyurethane foam, a viscoelastic polyurethane foam, or a polyurethane foam.

[0057] The thickness of the manifold 216 may also vary according to the needs of the indicated therapy. For example, the thickness of the manifold 216 may be reduced to reduce tension on the surrounding tissue of the tissue site 202. The thickness of the manifold 216 may affect the compatibility of the manifold 216. In some embodiments, a thickness in the range of about 5 millimeters to 10 millimeters may be appropriate.

[0058] In some exemplary embodiments, the manifold 216 may be hydrophilic. In one example where the manifold 216 may be hydrophilic, the manifold 216 may also wick fluid away from the tissue site 202 while continuing to distribute negative pressure to the tissue site 202. The wicking properties of the manifold 216 may draw fluid away from the tissue site 202 by capillary flow or other wicking mechanisms. One example of a hydrophilic material that may be suitable is an open-cell foam of polyvinyl alcohol, such as VACWHITEFOAM™ dressing available from Kinetic Concepts, Inc. (San Antonio, Texas). Other hydrophilic foams may include those made from polyethers. Other foams that may exhibit hydrophilic properties include hydrophobic foams that have been treated or coated to provide hydrophilicity.

[0059] In some embodiments, the manifold 216 may be constructed from a bioabsorbable material. Suitable bioabsorbable materials may include, but are not limited to, polymer blends of polylactic acid (PLA) and polyglycolic acid (PGA). Polymer blends may also include, but are not limited to, polycarbonate, polyfumarate, and capralactone. The manifold 216 may further serve as a scaffold for new cell growth, or a scaffold material may be used in conjunction with the manifold 216 to promote cell growth. A scaffold is generally a substance or structure used to enhance or promote cell growth or tissue formation, 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 hydroxyapatite, carbonate, or processed allograft materials.

[0060] When present, the film layer 214 may be disposed between the manifold 216 and the base layer 212. In embodiments without the base layer 212, the film layer 214 may be disposed between the manifold 216 and the tissue site 202. The film layer 214 may have a first surface 260 and a second surface 262 opposite the first surface 260. The first surface 260 of the film layer 214 may be adjacent to the second surface 252 of the manifold 216. The film layer 214 may have a perimeter 264 surrounding a central portion 266, a plurality of perforations 268 disposed through the perimeter 264, and a plurality of fenestrations 270 disposed through the central portion 266. The plurality of perforations 268 may be larger than the plurality of fenestrations 270. The film layer 214 may also have corners 272 and edges 274. The corners 272 and edges 274 may be part of the perimeter 264. One of the edges 274 may combine with another of the edges 274 to define one of the corners 272. Additionally, the film layer 214 may have a boundary 276 that substantially surrounds the central portion 266 and is positioned between the central portion 266 and the perimeter 264. The boundary 276 need not include the plurality of perforations 268 and the plurality of fenestrations 270.

[0061] The film layer 214 may be substantially the same shape as the base layer 212 such that the perimeter 264 of the film layer 214 is aligned with the perimeter 220 of the base layer 212 and the central portion 266 of the film layer 214 is aligned with the central portion 222 of the base layer 212. The perimeter 264 of the film layer 214 may be further aligned with the perimeter 238 of the cover 125. The perimeter 264 of the film layer 214 may be positioned proximate the perimeter 238 of the cover 125 such that the central portion 240 of the cover 125 and the central portion 266 of the film layer 214 define an enclosure 277. The perimeter 238 of the cover 125 may enclose the manifold 216 between the film layer 214 and the cover 125. The enclosure 277 may be configured to allow the manifold 216 to deform when exposed to a negative pressure, an axial force, a bending moment, or another force. The manifold 216 may be disposed within an enclosure 277 such that it is isolated from the adhesive 218 .

[0062] The plurality of fenestrations 270 may be substantially aligned with the base layer openings 232 such that the film layer 214 is configured to contact the tissue site 202 through the base layer openings 232. More specifically, the plurality of fenestrations 270, and at least a portion of the film layer 214, may be exposed to the tissue site through the base layer openings 232. In some embodiments, the base layer openings 232 may surround at least 90% of the plurality of fenestrations 270. In other embodiments, the base layer openings 232 may surround more than or less than 90% of the plurality of fenestrations 270 and may allow fluid communication from the tissue site 202 to the plurality of fenestrations 270. The plurality of perforations 268 of the film layer 214 may be aligned with the gaps 224 of the base layer 212 to allow the adhesive 218 to contact tissue substantially surrounding the tissue site 202, as described above. A central portion 266 of the film layer 214 may be configured to be in fluid communication with the tissue site 202 through the base layer opening 232 in the base layer 212 .

[0063] The plurality of perforations 268 of the film layer 214, if provided, may have another shape, such as, for example, a circle, a square, a star, an oval, a polygon, a slit, a compound curve, a linear shape, a triangle, or other shape, which may be aligned with the shape of the gap 224 of the base layer 212. The plurality of perforations 268 may be formed by cutting, applying localized RF energy, or another suitable technique for forming an opening. As shown in FIG. 3, each perforation 268 of the plurality of perforations 268 may be substantially circular in shape having a diameter and an area. The area of ​​each perforation 268 of the plurality of perforations 268 may refer to the open space or open area that defines each perforation 268 of the plurality of perforations 268. The diameter of each perforation 268 of the plurality of perforations 268 may define the area of ​​each perforation 268 of the plurality of perforations 268. For example, the area of ​​one of the plurality of perforations 268 may be defined by multiplying half the diameter of the perforation 268 by the value 3.14. Thus, the following formula may define the area of ​​one of the perforations 268: Area=3.14×(Diameter / 2)^2. The area of ​​the perforations 268 described in the exemplary embodiments herein may be substantially similar to the area of ​​other embodiments (not shown) of the perforations 268 that may have a non-circular shape. The diameter of each of the perforations 268 in the plurality of perforations 268 may be substantially the same, or each of the diameters may vary depending, for example, on the location of the plurality of perforations 268 in the film layer 214. Furthermore, the diameter of each of the perforations 268 in the plurality of perforations 268 may be from about 1 millimeter to about 50 millimeters. In some embodiments, the diameter of each of the perforations 268 in the plurality of perforations 268 may be from about 1 millimeter to about 20 millimeters. The plurality of perforations 268 may have a uniform pattern or may be randomly distributed in the film layer 214. The size and configuration of the plurality of perforations 268 may be designed to control the adhesion of the dressing 110 to the epidermis 204.

[0064] The central portion 266 of the film layer 214 may include a plurality of fenestrations 270. Each of the plurality of fenestrations 270 may be a slit or cut through the film layer 214 from the first surface 260 of the film layer 214 to the second surface 262 of the film layer 214. The plurality of fenestrations 270 may be formed by cutting, application of localized RF energy, die cutting, knife cutting, discontinuous slitting, or other suitable techniques for forming slits through the film layer 214. Similar to the slits or cuts forming the slits 254, the slits or cuts forming the plurality of fenestrations 270 may be distinguished from gaps or other openings in that a portion of material on either side of the fenestrations 270 is cut away or severed without removing material to form the fenestrations 270. In some embodiments, the film layer 214 may be bonded to the manifold 216 before the plurality of fenestrations 270 are formed in the film layer 214 and before the plurality of slits 254 are formed in the manifold 216. In some embodiments, the film layer 214 may be bonded to the manifold 216 and the plurality of fenestrations 270 and the plurality of slits 254 may be formed simultaneously. Forming the plurality of fenestrations 270 and the plurality of slits 254 together may ensure alignment of the plurality of fenestrations 270 and the plurality of slits 254. In other embodiments, the plurality of fenestrations 270 and the plurality of slits 254 may be formed separately in their respective layers and then the film layer 214 may be bonded to the manifold 216 such that the plurality of fenestrations 270 and the plurality of slits 254 are aligned. In this manner, the plurality of slits 254 and the plurality of fenestrations 270 may have the same shape.

[0065] The plurality of fenestrations 270 may be configured to deform when the dressing 110 is exposed to a negative pressure, such as a negative pressure from the negative pressure source 105. In some embodiments, the plurality of fenestrations 270 may be configured to deform when the dressing 110 is elongated or when the dressing 110 is exposed to an axial force or bending moment. The plurality of fenestrations 270 in the film layer 214 may be aligned with the plurality of slits 254 in the manifold 216. Each fenestration 270 in the plurality of fenestrations 270 may include a perimeter defined by or about opposing edges 279 of each of the plurality of fenestrations 270. Although the opposing edges 279 are illustrated in FIGS. 2-5 as linear cuts, the opposing edges 279 may be moveable or deformable between a closed state and an open state in the same manner or similar to the first and second side walls 256, 258 of the plurality of slits 254. Opposing edges 279 of each fenestration 270 of the plurality of fenestrations 270 may be positioned flush with the first and second side walls 256, 258 of the plurality of slits 254. Each fenestration 270 of the plurality of fenestrations 270 may be configured to deform in alignment with a corresponding slit 254 of the plurality of slits 254.

[0066] The film layer 214 may be made of a liquid impermeable film. In some embodiments, the film layer 214 may be made of a hydrophilic polyurethane, a cellulose derivative, a hydrophilic polyamide, a polyvinyl alcohol, a polyvinylpyrrolidone, a hydrophilic acrylic, a hydrophilic silicone elastomer, e.g., 14400 g / m 2The coating may include one or more of the following materials: INSPIRE 2301 material from Expopack Advanced Coatings (Wrexham, United Kingdom) having a MVTR (inverted cup technology) of 1 / 24 hours and a thickness of about 30 microns, a thin uncoated polymer drape, natural rubber, polyisoprene, styrene butadiene rubber, chloroprene rubber, polybutadiene, nitrile rubber, butyl rubber, ethylene propylene rubber, ethylene propylene diene monomer, chlorosulfonated polyethylene, polysulfide rubber, polyurethane (PU), EVA film, copolyester, silicone, silicone drape, 3M Tegaderm® drape, polyurethane (PU) drape such as those available from Avery Dennison Corporation (Pasadena, California), e.g., polyether block polyamide copolymer (PEBAX) from Arkema (France), Expopack 2327, or other suitable materials.

[0067] In some embodiments, the film layer 214 has a thickness of, for example, at least about 300 g / m 2 The manifold 216 may be a flexible, breathable film, membrane, or sheet having a high MVTR / 24 hours. In other embodiments, a drape with low or no vapor transfer may be used. The film layer 214 may comprise a range of medically suitable films having a thickness of about 15 microns (μm) to about 50 microns (μm). In other embodiments, the film layer 214 may be a non-breathable film, membrane, or sheet that may be substantially vapor and liquid impermeable. In some embodiments, the film layer 214 and the manifold 216 may be made of a resilient material to allow the film layer 214 and the manifold 216 to deform while aligned with one another. In some embodiments, the first surface 260 of the film layer 214 may be coated with an adhesive. The periphery 264, if provided, may include an adhesive and the central portion 266 may be free of adhesive. The adhesive may be similar to the adhesive 218 described above.

[0068] 2 and 3, the dressing interface 278 may be configured to fluidly couple the dressing 110 to the container 115 and the therapy unit 145. The therapy system 100 may further include a fluid conduit or conduit 280. The dressing interface 278 may be substantially as described above with reference to FIG. 1. In some embodiments, the dressing interface 278 may be an elbow connector that may be positioned over the gap 246 of the cover 125 to provide a fluid pathway between the conduit 280 and the tissue interface 120. The conduit 280 may be a flexible tube that may be fluidly coupled at one end to the dressing interface 278. The conduit 280 may be coupled to the container 115 or the therapy unit 145 by an end opposite the end coupled to the dressing interface 278.

[0069] 3 , in some embodiments, a handling bar 282 may be optionally included in the dressing 110. In some embodiments, the handling bar 282 may be disposed between the cover 125 and the adhesive 218. In other embodiments, the handling bar 282 may be disposed between the adhesive 218 and the film layer 214. In still other embodiments, the handling bar 282 may be disposed at a different location on the dressing 110. The handling bar 282 may be configured to allow a user or healthcare provider to place the dressing 110 at the tissue site 202. The handling bar 282 may prevent the user or healthcare provider from contacting the adhesive 218 while applying the dressing 110 to the tissue site 202. In some embodiments, the handling bar 282 may be configured to be removed from the dressing 110 after the dressing 110 is positioned at the tissue site 202, or may be removed along with the release liner 236 when the dressing 110 is placed at the tissue site 202. In other embodiments, the handling bar 282 may be partially or completely coated with an adhesive to allow the handling bar to lie flat on the tissue surrounding the tissue site 202 after the dressing 110 is positioned at the tissue site 202. In some embodiments, the handling bar 282 may be made of poly-coated paper or another material that is sturdy enough to place the dressing 110 in place at the tissue site 202.

[0070] 5 is a perspective view of the film layer 214 and manifold 216 of the dressing 110. The second surface 252 of the manifold 216 may be bonded to the first surface 260 of the film layer 214. The manifold 216 may be bonded to the central portion 266 of the film layer 214 such that the plurality of slits 254 of the manifold 216 are aligned with the plurality of fenestrations 270 of the film layer 214. At least a portion of the boundary 276 of the film layer 214 may contact the manifold 216 such that the manifold 216 contacts the entire central portion 266 of the film layer 214. Each slit 254 of the plurality of slits 254 may have a length 502. Each fenestration 270 of the plurality of fenestrations 270 may have a length equal to length 502 such that a periphery or opposite edge 279 of each fenestration 270 of the plurality of fenestrations 270 may be positioned flush with the first side wall 256 and the second side wall 258 of a corresponding slit 254 of the plurality of slits 254. Thus, each slit 254 of the plurality of slits 254 may be the same size and shape as the corresponding fenestration 270 of the plurality of fenestrations 270.

[0071] 6A-6D, one embodiment of a manifold 216 is shown that includes slits 254 positioned at different orientations.

[0072] 6A is a top view of manifold 216 in a resting state. In the resting state, no force is acting on the manifold, and each slit 254 of the plurality of slits 254 may be in a closed state. In some embodiments, each slit 254 of the plurality of slits 254 may include a first slit 254a, a second slit 254b, a third slit 254c, a fourth slit 254d, a fifth slit 254e, a sixth slit 254f, a seventh slit 254g, an eighth slit 254h, and a ninth slit 254i. Each of the first slit 254a, the second slit 254b, the third slit 254c, the fourth slit 254d, the fifth slit 254e, the sixth slit 254f, the seventh slit 254g, the eighth slit 254h, and the ninth slit 254i may be a linear cut and may include a first sidewall 256 and a second sidewall 258 that may extend between the first surface 250 and the second surface 252 of the manifold 216.

[0073] 6A , the plurality of fenestrations 270 in the film layer 214 may have the same size and shape as the plurality of slits 254 in the manifold 216. The plurality of slits 254 in the manifold 216 may be aligned with the plurality of fenestrations 270 in the film layer 214 such that when the dressing 110 is exposed to a force, such as negative pressure from the negative pressure source 105, the plurality of slits 254 in the manifold 216 are configured to deform in alignment with the plurality of fenestrations 270 in the film layer 214.

[0074] In other embodiments, the slits 254 through the manifold 216 may be positioned in another orientation, pattern, or length that may cut through the manifold 216. In some embodiments, the slits 254 may be uniformly distributed throughout the manifold 216. In other embodiments, the slits 254 may be randomly distributed throughout the manifold 216. In any of the described embodiments, the slits 254 in the manifold may allow the manifold 216 to deform in response to forces applied to the dressing 110.

[0075] FIG 6B is a top view of the manifold 216 of FIG 6A with a force 602 acting on it. The force 602 may act on the first half 604 of the manifold 216 and the second half 606 of the manifold 216 such that the first half 604 is pulled away from the second half 606 and the second half 606 is pulled away from the first half 604. When the force 602 acts, some of the plurality of slits 254 may deform from the closed state of FIG 6A to an open state. Each slit 254 of the plurality of slits 254 may deform independently of another one of the plurality of slits 254. For example, the plurality of slits proximate the force 602 may deform from a closed state to an open state, while the plurality of slits 254 further from the force 602 may not deform and may remain in a closed state.

[0076] When in the open state, there may be a slit opening 608 defined through the plurality of slits 254 of the manifold 216. In the embodiment of FIGS. 2-5, when subjected to a force, such as force 602 as illustrated in FIGS. 6A-6D, a slit opening, such as slit opening 608, may be defined between the first sidewall 256 and the second sidewall 258. As shown in FIGS. 6A and 6B, depending on the direction and nature of the applied force, the slit opening 608 may be formed between at least one of the first slit 254a, the second slit 254b, the third slit 254c, the fourth slit 254d, the fifth slit 254e, the sixth slit 254f, the seventh slit 254g, the eighth slit 254h, and the ninth slit 254i. For example, the first sidewall 256 can be separated from the second sidewall 258 at each of the first slit 254a, the second slit 254b, the third slit 254c, the fourth slit 254d, the fifth slit 254e, the sixth slit 254f, the seventh slit 254g, the eighth slit 254h, and the ninth slit 254i if the applied force is substantially uniform across the entire surface area of ​​the manifold 216 or is greater than a threshold amount. However, the first sidewall 256 may be separated from the second sidewall 258 at only some of the first slits 254a, the second slits 254b, the third slits 254c, the fourth slits 254d, the fifth slits 254e, the sixth slits 254f, the seventh slits 254g, the eighth slits 254h, and the ninth slits 254i if the applied force is not uniform across the entire surface area of ​​the manifold 216 or is less than a threshold amount at one or more locations. For example, the first side wall 256 may be separated from the second side walls 258 of the first slit 254a, the second slit 254b, the third slit 254c, the fourth slit 254d, and the fifth slit 254e, but the first side wall 256 may be coupled to the second side walls 258 of the sixth slit 254f, the seventh slit 254g, the eighth slit 254h, and the ninth slit 254i.The first side wall 256 may be separated from the second side wall 258 at other combinations of the first slit 254a, the second slit 254b, the third slit 254c, the fourth slit 254d, the fifth slit 254e, the sixth slit 254f, the seventh slit 254g, the eighth slit 254h, and the ninth slit 254i depending on the location of the force 602 acting on the manifold 216.

[0077] In some embodiments, the plurality of slits 254 closer to the force 602 may deform more than the plurality of slits 254 further from the force 602. For example, the slit opening 608a of the plurality of slits 254 closest to the force 602 may be larger than the slit opening 608b further from the force 602. In some embodiments, there may be a slit opening 608c that is an equal distance between the force 602 on the first half 604 and the force 602 on the second half 606. The slit opening 608c may be larger than both the slit opening 608a and the slit opening 608b.

[0078] FIG. 6C is a top view of the manifold 216 of FIG. 6A with a force 610 acting on it. The force 610 may act on a first corner 612 of the manifold 216 and a second corner 614 of the manifold 216. The first corner 612 may be opposite the second corner 614, and the force 610 may pull the first corner 612 away from the second corner 614 while also pulling the second corner 614 away from the first corner 612. When the force 610 acts, some of the plurality of slits 254 may deform from the closed state of FIG. 6A to an open state. Each slit 254 of the plurality of slits 254 may deform independently of another one of the plurality of slits 254. For example, a plurality of slits proximate to the force 610 may deform from a closed state to an open state to create a slit opening 608d. The slits further from the force 610 may not deform as much, so the slit openings 608 e of the slits 254 further from the force 610 will be smaller than the slit openings 608 a of the slits 254 closer to the force 610 .

[0079] FIG. 6D is a top view of the manifold 216 of FIG. 6A with a force 616 acting on it. The force 616 may act on a first edge 618 of the manifold and a second edge 620 of the manifold 216. The first edge 618 may be opposite the second edge 620, and the force 616 may pull the first edge 618 away from the second edge 620 while also pulling the second edge 620 away from the first edge 618. When the force 616 acts on some of the plurality of slits 254 may deform from the closed state of FIG. 6A to an open state. Each slit 254 of the plurality of slits 254 may deform independently of another one of the plurality of slits 254. For example, a plurality of slits proximate to the force 616 may deform from a closed state to an open state to create a slit opening 608f. The slits 254 that are further from the force 610 may not deform as much to create the slit opening 608g. The slits 254 with the slit opening 608g may be at equal distances from the force 616 of the first edge 618 and the force 616 of the second edge 620. The force 616 of the first edge 618 and the force 616 of the second edge 620 may act equally on the slits 254 with the slit opening 608g. Each slit 254 of the plurality of slits 254 that are closer to the force 616 of the first edge 618 or the force 616 of the second edge 620 may act unevenly on the force 616 to the first edge 618 and the force 616 to the second edge 620, which may result in a slit opening 608f that is smaller than the slit opening 608g.

[0080] Referring to Figure 7, another embodiment of the dressing 110 is shown. The dressing interface 278, conduits 280, cover 125, adhesive 218, manifold 216, base layer 212, and release liner 236 may be substantially as described with reference to Figures 2-4. The dressing 110 of Figure 7 may include a film layer 702 positioned between the manifold 216 and the base layer 212. The film layer 702 may be similar to the central portion 266 of the film layer 214 described above. In some embodiments, the dressing 110 may further include a handling bar similar to the handling bar 282 described above with reference to Figure 3.

[0081] The film layer 702 may be substantially the same shape as the manifold 216 and the base layer openings 232. The film layer 702 may contact the tissue site 202 through the base layer openings, substantially as described above. The film layer 702 may include a first surface 704, a second surface 706, and a plurality of fenestrations 708. The first surface 704 of the film layer 702 may be configured to couple to the second surface 252 of the manifold 216. Each fenestration 708 of the plurality of fenestrations 708 may be a slit or cut through the film layer 702 from the first surface 704 of the film layer 702 to the second surface 706 of the film layer 702. The plurality of fenestrations 708 of the film layer 702 may be aligned with the plurality of slits 254 of the manifold 216. The plurality of fenestrations 708 may be configured to deform in coordination with the plurality of slits 254 in the manifold 216 when the dressing 110 is subjected to a force, such as a bending moment or negative pressure from the negative pressure source 105 .

[0082] The manifold 216 and film layer 702 may be isolated from the adhesive 218 and may be substantially aligned with the central portion 240 of the cover and the central portion 222 of the base layer 212. The adhesive 218 may be exposed to the tissue surrounding the tissue site 202 through the gaps 224 in the base layer 212 without contacting the film layer 702.

[0083] Also described herein is a method for treating a tissue site, such as tissue site 202. The method may include applying a dressing 110 to the tissue site 202, fluidly coupling a negative pressure source 105 to the dressing 110, and activating the negative pressure source 105 to apply negative pressure to the dressing 110. The dressing 110 may include a foam, such as a manifold 216, which may include a plurality of slits 254. The dressing 110 may further include a film layer 214. The film layer 214 may be positioned between the foam and the tissue site 202. The film layer 214 may include a plurality of fenestrations 270 configured to align with the plurality of slits 254 in the foam. The multiple slits 254 in the foam can deform in coordination with the multiple fenestrations 270 in the film layer 214 when the dressing 110 is wrapped around, forced into, or otherwise conformed to the shape of a particular tissue site, when negative pressure is applied to the dressing 110, and / or when it is exposed to another force, such as a bending moment.

[0084] The systems, devices, and methods described herein may provide significant advantages. For example, the manifold 216 having multiple slits 254 may reduce the risk of tissue ingrowth into the dressing 110. In contrast to traditional gaps or openings, the configuration of slits 254 prevents a portion of the manifold 216 from being sucked through the fenestrations 270 in the film layer 214 while under negative pressure and coming into direct contact with the tissue site where tissue ingrowth may occur. Additionally, the multiple slits 254 in the manifold 216 may be aligned with the multiple fenestrations 270 in the film layer 214 to support removal of thick exudate from the tissue site 202. Additionally, the multiple slits 254 in the manifold 216 may create a more uniform distribution of negative pressure from the negative pressure source 105 to the tissue site 202 and may support wound healing by disrupting biofilm in the wound bed of the tissue site 202.

[0085] Although shown in several exemplary embodiments, those skilled in the art will recognize that the systems, devices, and methods described herein are capable of various changes and modifications that are within the scope of the appended claims. Moreover, the description of various alternatives using terms such as "or" does not require mutual exclusivity unless clearly required by the context, and the indefinite article "a" or "an" does not limit the subject matter to a single instance unless clearly required by the context. Components may also be combined or excluded in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations, the dressing 110, the container 115, or both may be excluded or separated from the components for manufacture or sale. In other exemplary configurations, the controller 130 may also be manufactured, configured, assembled, or sold independently of other components.

[0086] Although the appended claims set forth novel and inventive aspects of the subject matter described above, the claims may also encompass additional subject matter not specifically described in detail. For example, certain features, elements, or aspects may be omitted from the claims if they are not necessary to distinguish the novel and inventive features from those already known to those skilled in the art. Features, elements, and aspects described in the context of some embodiments may also be omitted, combined, or replaced by alternative features serving the same, equivalent, or similar purpose without departing from the scope of the invention as defined by the appended claims.

Claims

1. 1. A dressing for treating a tissue site with negative pressure, said dressing comprising: a cover having a first surface and a second surface; a foam having a first surface, a second surface, and a plurality of slits, the first surface of the foam being adjacent to the second surface of the cover, the plurality of slits being deformable between a closed state and an open state, the foam having a first sidewall and a second sidewall extending between the first and second surfaces of the foam, wherein in the closed state, the first sidewall is in contact with the second sidewall and in the open state, the first sidewall is separated from the second sidewall; a film layer having a first surface, a second surface, and a plurality of fenestrations through the first and second surfaces, the plurality of fenestrations aligned with the plurality of slits in the foam, and the first surface of the film layer adjacent the second surface of the foam.

2. The dressing of claim 1 , wherein the foam is positioned between the cover and the film layer.

3. 10. The dressing of claim 1, wherein the plurality of slits in the foam are configured to deform from the closed state to the open state when the dressing is subjected to the negative pressure, axial force, or bending moment.

4. 10. The dressing of claim 1, wherein the first side wall is positioned across the slit openings of the plurality of slits opposite the second side wall.

5. The dressing of claim 1 , wherein one or more of the plurality of slits is transformable between the closed and open states independently of another of the plurality of slits.

6. 10. The dressing of claim 1, wherein the plurality of fenestrations in the film layer are configured to deform in alignment with the plurality of slits in the foam when the dressing is subjected to the negative pressure.

7. 2. The dressing of claim 1, wherein the plurality of fenestrations in the film layer and the plurality of slits in the foam are aligned in both the open and closed states and are configured to deform in a coordinated manner in response to the negative pressure.

8. 8. The dressing of claim 7, wherein the plurality of fenestrations each include opposing edges positioned flush with the first and second side walls of the plurality of slits.

9. The dressing of claim 1 , wherein the film layer is bonded to the foam.

10. 10. The dressing of claim 1, further comprising a base layer adjacent the second surface of the film layer, the base layer comprising a central portion including a base layer opening and a peripheral portion including a plurality of gaps.

11. 11. The dressing of claim 10, wherein the peripheral portion surrounds the central portion, and the plurality of gaps in the peripheral portion are smaller than the base layer openings in the central portion.

12. The dressing of claim 10, wherein the base layer opening is a single opening.

13. 11. The dressing of claim 10, wherein the plurality of fenestrations and at least a portion of the film layer are exposed through the base layer openings.

14. 11. The dressing of claim 10, wherein the film layer is configured to contact the tissue site through the base layer opening, and the peripheral portion of the base layer is configured to contact tissue surrounding the tissue site.

15. 15. The dressing of claim 14, wherein the base layer does not contact the tissue site.

16. The dressing of claim 10 , wherein the base layer comprises a silicone gel configured to contact tissue surrounding the tissue site.

17. 11. The dressing of claim 10, wherein the film layer comprises a central portion including the plurality of fenestrations aligned with the foam and a peripheral portion extending beyond the foam and including a plurality of perforations surrounding the plurality of fenestrations, the perforations being larger than the plurality of fenestrations and configured to align with the plurality of gaps in the base layer.

18. 1. A system for treating a tissue site with negative pressure, the system comprising: The dressing material according to claim 1; a negative pressure source configured to be fluidly coupled to the dressing.

19. 1. A tissue interface for treating a tissue site with negative pressure, comprising: a manifold layer comprising a plurality of slits, each slit comprising a first sidewall and a second sidewall; a film layer bonded to the surface of the manifold layer and having a plurality of fenestrations, each of the plurality of fenestrations including opposing edges positioned flush with the first and second side walls of the plurality of slits.

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