Tissue interface for tissue debridement

Abstract

Dressings, systems, and methods for treating a tissue site are described. A method of manufacturing a dressing can include providing a dressing. The dressing can have a surface configured to contact the tissue site. The dressing can also have a plurality of pores. The method can further include applying a compressive force to the dressing at an angle to the surface, the compressive force causing permanent deformation of the plurality of pores. Causing permanent deformation of the plurality of pores can include forming a plurality of compressed pores. Forming the plurality of compressed pores can include compressing the plurality of pores from a generally circular shape to a generally oval shape.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 049,884, filed July 9, 2020, which is incorporated herein by reference in its entirety.

[0002] The present invention as claimed below relates generally to tissue treatment systems and particularly, but not exclusively, to dressings for tissue treatment and methods of using dressings for tissue treatment. [Background technology]

[0003] Clinical studies and clinical practice have shown that reducing pressure in the vicinity of a tissue site can enhance and accelerate the growth of new tissue at the tissue site. While the applications of this phenomenon are numerous, it has proven particularly advantageous for treating wounds. Regardless of the cause of the wound, whether traumatic, surgical, or otherwise, proper care of the wound is critical to the outcome. Treatment of wounds or other tissues with reduced pressure may generally be 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," "negative pressure wounds," and "topical negative pressure." Negative pressure therapy can provide many benefits, including epithelial and subcutaneous tissue migration, improved blood flow, and minimal tissue deformation at the wound site. Collectively, these benefits can increase granulation tissue development and reduce healing time.

[0004] It is also widely accepted that cleansing a tissue site can be highly beneficial to new tissue growth. For example, a wound or cavity can be flushed with a therapeutic liquid solution. These actions are commonly referred to as "irrigation" and "lavage," respectively. "Dripping" is another action that generally refers to the process of slowly introducing fluid into a tissue site, leaving the fluid there for a prescribed period of time, and then removing the fluid. For example, dripping a topical therapeutic solution onto a wound bed, combined with negative pressure therapy, can further promote wound healing by agitating soluble contaminants in the wound bed and removing infectious materials. As a result, the soluble bacterial load can be reduced, contaminants can be removed, and the wound can be cleansed.

[0005] While the clinical benefits of negative pressure and / or infusion therapy are widely known, improvements in treatment systems, components, and processes can benefit healthcare providers and patients. Summary of the Invention

[0006] New and useful systems, devices, and methods for treating tissue in a negative pressure therapy environment are set forth in the accompanying claims. Exemplary embodiments are also provided to enable one of ordinary skill in the art to make and use the claimed subject matter.

[0007] For example, in some embodiments, a method of manufacturing a dressing for treating a tissue site is described. The method can include providing a dressing. The dressing can have a surface configured to contact the tissue site. The dressing can also have a plurality of pores. The method can further include applying a compressive force to the dressing at an angle relative to the surface, the compressive force causing permanent deformation of the plurality of pores. In some embodiments, causing permanent deformation of the plurality of pores can include forming a plurality of compressed pores. Forming the plurality of compressed pores can include compressing the plurality of pores from a generally circular shape to a generally oval shape. In some embodiments, the method can further include orienting major axes of the oval pores perpendicular to the surface.

[0008] More generally, a dressing for treating a tissue site is described. The dressing can include a first surface configured to face the tissue site, a second surface opposite the first surface, a thickness extending from the first surface to the second surface, and a plurality of elliptical pores. The plurality of pores can have major axes oriented perpendicular to the first and second surfaces.

[0009] Alternatively, other exemplary embodiments may describe a system for providing negative pressure therapy to a tissue site. The system may include a tissue interface, a sealing member disposed across the tissue interface and configured to create a sealed space, and a negative pressure source fluidly coupled to the sealed space. The tissue interface may include a first surface configured to face the tissue site, a second surface opposite the first surface, a thickness extending from the first surface to the second surface, and a plurality of pores. Each of the plurality of pores may have an oval shape oriented at an angle relative to the first surface. In some embodiments, the angle may be approximately 90°. The plurality of pores may be configured to contract in a direction parallel to the first and second surfaces.

[0010] Also described herein is a tissue interface for treating a tissue site, which can be formed by a process including providing a dressing and applying a compressive force to the dressing. The dressing can have a surface configured to contact the tissue site and a plurality of pores. The compressive force can be applied to the dressing at an angle relative to the surface. The compressive force can also cause permanent deformation of the plurality of pores.

[0011] Methods for treating a tissue site with negative pressure are also described herein. In some exemplary embodiments, the method can include applying a tissue interface to the tissue site. The tissue interface can include a first surface configured to face the tissue site, a second surface opposite the first surface, a thickness extending from the first surface to the second surface, and a plurality of pores. The plurality of pores can have an elliptical shape and a major axis oriented perpendicular to the first and second surfaces. The method can further include covering the tissue interface with a cover to form a sealed space containing the tissue interface, fluidly coupling a fluid conduit to the tissue interface, fluidly coupling a negative pressure source to the fluid conduit, applying negative pressure from the negative pressure source through the fluid conduit to the tissue interface, and contracting the tissue interface from a first width to a second width in response to the application of negative pressure to the tissue interface. The second width can be smaller than the first width. In some embodiments, the plurality of pores can be configured to contract in a direction parallel to the first and second surfaces.

[0012] The objects, advantages and preferred modes of making and using the claimed subject matter will best be understood by referring to the following detailed description of illustrative embodiments in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a functional block diagram of an exemplary embodiment of a treatment system capable of providing negative pressure and instillation treatment in accordance with the present disclosure. [Figure 2] 2 is an assembled view of the dressing example of FIG. 1 showing additional details that may be relevant to some embodiments. [Figure 3] 3 is a plan view of the tissue interface of FIG. 2 showing additional details that may be relevant to some embodiments. [Figure 4] 4 is a cross-sectional view of the tissue interface of FIG. 3 showing additional details that may be relevant to some embodiments. [Figure 5] FIG. 5 is a detail view showing further details that may be associated with some embodiments of the plurality of pores of the tissue interface of FIG. 4. [Figure 6] FIG. 6 is a detail view showing further details that may be associated with some embodiments of the pores of FIG. 5. [Figure 7] 4 is a plan view showing further details that may be associated with some embodiments of the pores of the tissue interface of FIG. 3. FIG. [Figure 8] FIG. 4 is a plan view showing further details of a portion of the tissue interface of FIG. 3. [Figure 9] FIG. 4 is a plan view showing further details of the tissue interface of FIG. 3 in a contracted state. [Figure 10] FIG. 6 is a detail view showing further details that may be associated with the pores of the tissue interface of FIG. 5 in a contracted state. [Figure 11] 3 is a cross-sectional view of a portion of the tissue interface of FIG. 2 showing further details that may be relevant to some embodiments. [Figure 12] 3 is a cross-sectional view of the tissue interface of FIG. 2 during negative pressure therapy, showing further details that may be relevant to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0014] The following description of exemplary embodiments provides information to enable one skilled in the art to make and use the claimed subject matter, but may omit certain details already known in the art. Thus, the following detailed description is to be construed as illustrative and not limiting.

[0015] Exemplary embodiments may also be described herein with reference to the spatial relationships between or orientation of various elements as shown in the accompanying drawings. Generally, such relationships or orientations are in a frame of reference that is consistent with or relative to a patient in a position to receive treatment. However, those skilled in the art will understand that this frame of reference is not a strict requirement and is merely for convenience of explanation.

[0016] FIG. 1 is a simplified functional block diagram of an exemplary embodiment of a treatment system 100 according to the present disclosure, which is capable of providing negative pressure therapy using instillation of a topical treatment solution to a tissue site.

[0017] 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, nerve tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendon, or ligament. Wounds can include, for example, chronic, acute, traumatic, subacute, and dehiscence wounds, partial-thickness burns, ulcers (such as diabetic ulcers, pressure ulcers, or venous insufficiency ulcers), skin flaps, and transplanted tissue. The term "tissue site" can also refer not necessarily to any area of ​​tissue where there is a wound or defect, but instead to an area where 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, which can then be harvested and transplanted.

[0018] Treatment system 100 may include a negative pressure source or supply, such as negative pressure source 102, and one or more distribution components. The distribution components are preferably detachable and may be disposable, reusable, or recyclable. Dressings, such as dressing 104, and fluid containers, such as container 106, are examples of distribution components that may be associated with some embodiments of treatment system 100. As shown in the example of FIG. 1, dressing 104 may include or consist essentially of tissue interface 108, cover 110, or both in some embodiments.

[0019] A fluid conduit is another illustrative example of a distribution component. In this context, "fluid conduit" broadly includes a tube, pipe, hose, conduit, or other structure having one or more lumens or open passages adapted to transport fluid between two ends. Typically, a tube is an elongated, cylindrical structure with some flexibility, although the geometry and stiffness can 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 a fluid conduit to a dressing 104. For example, such a dressing interface may be a SENSAT.RAC™ Pad available from Kinetic Concepts, Inc. (San Antonio, Texas).

[0020] The treatment system 100 may also include a regulator or controller, such as a controller 112. Additionally, the treatment system 100 may include sensors for measuring operating parameters and providing feedback signals indicative of the operating parameters to the controller 112. For example, as shown in FIG. 1, the treatment system 100 may include a first sensor 114 and a second sensor 116 coupled to the controller 112.

[0021] The treatment system 100 may also include a source of instillation solution. For example, the solution source 118 may be fluidly coupled to the dressing 104, as shown in the exemplary embodiment of FIG. 1 . In some embodiments, the solution source 118 may be fluidly coupled to a positive pressure source, such as the positive pressure source 120, a negative pressure source, such as the negative pressure source 102, or both. A regulator, such as the drip regulator 122, may also be fluidly coupled to the solution source 118 and the dressing 104 to ensure proper administration of the instillation solution (e.g., saline) to the tissue site. For example, the drip regulator 122 may include a piston that may be pneumatically actuated by the negative pressure source 102 to draw the instillation solution from the solution source during negative pressure intervals and to instill the solution onto the dressing during ventilation intervals. Additionally or alternatively, the controller 112 may be coupled to the negative pressure source 102, the positive pressure source 120, or both to control the administration of the instillation solution to the tissue site. In some embodiments, the drip regulator 122 may also be fluidly coupled to the negative pressure source 102 via the dressing 104, as shown in the example of FIG.

[0022] Some components of the treatment system 100 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 102 may be combined with the controller 112, the solution source 118, and other components into a treatment unit.

[0023] In general, the components of the treatment system 100 may be directly or indirectly coupled. For example, the negative pressure source 102 may be directly coupled to the container 106 or indirectly coupled to the dressing 104 via the container 106. The coupling may include fluid coupling, mechanical coupling, thermal coupling, electrical coupling, or chemical coupling (such as a chemical bond), or, in some contexts, some combination of couplings. For example, the negative pressure source 102 may be electrically coupled to the controller 112 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 being integrated into a single structure, or by being formed from the same piece of material.

[0024] A negative pressure source, such as negative pressure source 102, may be a reservoir of air at negative pressure or may be a manual or powered device, such as a vacuum pump, a suction pump, a 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 environment outside the sealed treatment environment. Often, the local ambient pressure may also be the 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, pressure values ​​described herein are gauge pressures. References to increased negative pressure typically refer to decreases in absolute pressure, and decreases in negative pressure typically refer to increases in absolute pressure. While the amount and nature of the negative pressure provided by negative pressure source 102 may vary depending on treatment requirements, the pressure is typically a low vacuum, also commonly referred to as a rough vacuum, between -5 mmHg (-667 Pa) and -500 mmHg (-66.7 kPa). A typical therapeutic range is between -50 mmHg (-6.7 kPa) and -300 mmHg (-39.9 kPa).

[0025] Container 106 represents a container, canister, pouch, or other storage component that may be used to manage exudate and other fluids drawn from a tissue site. In many environments, a rigid container may be preferred or required for fluid collection, storage, and disposal. In other environments, fluids may be properly disposed of without being stored in a rigid container, and a reusable container may reduce waste and costs associated with negative pressure therapy. In some embodiments, container 106 may comprise a canister having a collection chamber, a first inlet fluidly coupled to the collection chamber, and a first outlet fluidly coupled to the collection chamber and adapted to receive negative pressure from a negative pressure source.

[0026] The tissue interface 108 may generally be adapted to partially or completely contact the tissue site. The tissue interface 108 may take many forms and may have many sizes, shapes, or thicknesses, depending on various factors, such as the type of procedure being performed or the nature and size of the tissue site. The tissue interface 108 may further promote granulation at the tissue site when pressure within the sealed therapy environment is reduced. For example, the size and shape of the tissue interface 108 may be adapted to the contours of a deep, irregularly shaped tissue site. Some or all of the surface of the tissue interface 108 may have an uneven, rough, or jagged profile, which may induce microstrains and stresses at the tissue site when negative pressure is applied through the tissue interface 108.

[0027] In some embodiments, the tissue interface 108 may comprise or essentially consist of a manifold. A manifold in this context may comprise or essentially consist of a means for collecting or distributing fluid across the tissue interface 108 under pressure. For example, the manifold may be adapted to receive negative pressure from a source and distribute the negative pressure across the tissue interface 108 via a plurality of openings, which may have the effect of collecting fluid across the 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 delivery of fluid across the tissue site, such as fluid from a source of instillation solution.

[0028] The tissue interface 108 can be either hydrophobic or hydrophilic. In instances where the tissue interface 108 may be hydrophilic, the tissue interface 108 can also wick fluid away from the tissue site while continuing to distribute negative pressure to the tissue site. The wicking properties of the tissue interface 108 can draw fluid away from the tissue site 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 characteristics include hydrophobic foams that have been treated or coated to impart hydrophilic properties.

[0029] In some embodiments, the tissue interface 108 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 tissue interface 108 may further function as a scaffold for new cell growth, or a scaffold material may be used in conjunction with the tissue interface 108 to promote cell growth. A scaffold is generally a substance or structure used to enhance or promote 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 engineered allograft materials.

[0030] In some embodiments, the cover 110 can provide a barrier against bacteria and protection from physical trauma. The cover 110 can also be constructed from a material that can reduce evaporative loss and provide a fluid seal between two components or two environments, such as a fluid seal between a therapy environment and a local external environment. The cover 110 can include or consist of, for example, an elastomeric film or membrane that can provide a seal suitable for maintaining the negative pressure of a given negative pressure source at the tissue site. In some applications, the cover 110 can have a high moisture-vapor transmission rate (MVTR). For example, the MVTR can be at least 250 grams per square meter per 24 hours as measured using the Upright Cup Method of ASTM E96 / E96M at 38°C and 10% relative humidity (RH). In some embodiments, an MVTR of up to 5,000 grams per square meter per 24 hours can provide effective breathability and mechanical properties.

[0031] In some exemplary embodiments, the cover 110 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 to 50 microns. For permeable materials, the permeability should generally be low enough to maintain the desired negative pressure. The cover 110 may include, for example, one or more of the following materials: polyurethanes (PU), such as hydrophilic polyurethanes; cellulose derivatives; hydrophilic polyamides; polyvinyl alcohol; polyvinylpyrrolidone; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubber; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl acetate (EVA); copolyesters; and polyether block polyimide copolymers. Such materials are commercially available, for example, as 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 110 has a thickness of 2600 g / m 2 / INSPIRE2301 having a 24 hour MVTR (upright cup method) and a thickness of approximately 30 microns.

[0032] An attachment device may be used to attach the cover 110 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 110 to the epidermis around the tissue site. In some embodiments, for example, part or all of the cover 110 may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight of approximately 25-65 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 double-sided tape, glue, hydrocolloid, hydrogel, silicone gel, or organogel.

[0033] The solution source 118 may also represent a container, canister, pouch, bag, or other storage component capable of providing a solution for instillation therapy. While the composition of the solution may vary depending on the indicated therapy, examples of solutions that may be suitable for some formulations include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions.

[0034] In operation, the tissue interface 108 may be positioned within, on, over, or otherwise adjacent to the tissue site. For example, if the tissue site is a wound, the tissue interface 108 may partially or completely occlude or be positioned over the wound. The cover 110 may be positioned over the tissue interface 108 and sealed to a mounting surface adjacent the tissue site. For example, the cover 110 may be sealed to intact epidermis surrounding the tissue site. Thus, the dressing 104 can provide a sealed treatment environment adjacent the tissue site that is substantially isolated from the external environment, and the negative pressure source 102 can reduce pressure in that sealed treatment environment.

[0035] The fluid dynamics of using a negative pressure source to reduce pressure in another component or location, such as within a sealed treatment environment, can be mathematically complex, but the basic principles of fluid dynamics applicable to negative pressure therapy and instillation are generally well known to those skilled in the art, and the process of reducing pressure can be illustratively described herein as, for example, "delivering," "distributing," or "generating" negative pressure.

[0036] Generally, exudate and other fluids flow along a fluid pathway toward lower pressure. Thus, the term "downstream" typically refers to a location within a 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 location that is relatively farther away from a negative pressure source or closer to a positive pressure source. 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 assumed for purposes of describing various features and components herein. However, fluid pathways may also be reversed in some applications, such as by replacing a negative pressure source with a positive pressure source, and this descriptive definition should not be construed as limiting.

[0037] In a sealed treatment environment, negative pressure applied across the tissue site via tissue interface 108 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 container 106.

[0038] A controller, such as controller 112, may be a microprocessor or computer programmed to operate one or more components of treatment system 100, such as negative pressure source 102. In some embodiments, for example, controller 112 may be a microcontroller, which generally includes an integrated circuit including a processor core and memory programmed to directly or indirectly control one or more operating parameters of treatment system 100. The operating parameters may include, for example, the power applied to negative pressure source 102, the pressure generated by negative pressure source 102, or the pressure delivered to tissue interface 108. Controller 112 is also preferably configured to receive one or more input signals, such as feedback signals, and is programmed to modify one or more operating parameters based on the input signals.

[0039] Sensors, such as the first sensor 114 and the second sensor 116, are generally known in the art as any device 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 114 and the second sensor 116 may be configured to measure one or more operating parameters of the treatment system 100. In some embodiments, the first sensor 114 may be a transducer configured to measure the pressure in the air passageway and convert the measurement into a signal indicative of the measured pressure. In some embodiments, for example, the first sensor 114 may be a piezoresistive strain gauge. In some embodiments, the second sensor 116 may optionally measure an operating parameter of the negative pressure source 102, such as voltage or current. Preferably, the signals from the first sensor 114 and the second sensor 116 are suitable as input signals to the controller 112, 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 112. Typically, the signal is an electrical signal, but may be represented in other forms, such as an optical signal.

[0040] In some embodiments, the controller 112 can receive and process data from one or more sensors, such as the first sensor 114. The controller 112 can also control the operation of one or more components of the treatment system 100 to manage the pressure delivered to the tissue interface 108. In some embodiments, the controller 112 can include an input for receiving a desired target pressure and can be programmed to process data regarding the setting and input of the target pressure to be applied to the tissue interface 108. In some exemplary embodiments, the target pressure can be a fixed pressure value, which 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 112. 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 patient's health, and the attending physician's preferences. After selecting the desired target pressure, the controller 112 can operate the negative pressure source 102 in one or more control modes based on the target pressure and can receive feedback from one or more sensors to maintain the target pressure at the tissue interface 108.

[0041] During tissue site treatment, some tissue sites may not heal according to normal medical protocols and may develop areas of necrotic tissue. Necrotic tissue can be dead tissue resulting from infection, poison, or trauma, which causes tissue to die faster than it can be removed by the body's normal processes regulating the removal of dead tissue. Sometimes, necrotic tissue can be in the form of slough, which can contain a viscous liquid mass of tissue. Slough is generally caused by bacterial and fungal infections that stimulate an inflammatory response in the tissue. Slough can be creamy yellow and sometimes referred to as pus. Necrotic tissue can also include scabs, which can be portions of necrotic tissue that have dried and hardened. Scabs can be the result of burns, gangrene, ulcers, fungal infections, spider bites, or anthrax. Removing scabs can be difficult without the use of surgical excision instruments.

[0042] For example, in addition to necrotic tissue, slough, and scab, a tissue site may contain biofilm, necrotic tissue, lacerated tissue, devitalized tissue, contaminated tissue, damaged tissue, infected tissue, exudate, thick exudate, fibrinous slough, and / or other material that may generally be referred to as debris. Debris may inhibit the effectiveness of tissue treatment and delay healing of the tissue site. If debris is present within the tissue site, the tissue site may be treated with various processes to destroy the debris. Examples of destruction may include softening the debris, separating the debris from desired tissue, such as subcutaneous tissue, preparing the debris for removal from the tissue site, and removing the debris from the tissue site.

[0043] The debris may require debridement, which may be performed in an operating room. In some cases, the tissue site requiring debridement may not be life-threatening, and debridement may be considered a low priority. Low-priority cases may experience delays before treatment as other, more life-threatening cases are given priority in the operating room. As a result, low-priority cases may require palliative care. Palliative care may include stasis of fluid flow at the tissue site, which limits deterioration of the tissue site before other therapies, such as debridement, negative pressure therapy, or instillations.

[0044] During debridement, clinicians may find it difficult to distinguish between healthy, viable tissue and necrotic tissue. As a result, typical debridement techniques may remove too much healthy tissue or not enough necrotic tissue. When the nonviable tissue border does not extend deeper than the deep dermis layer, or when the tissue site is covered by debris such as slough or fibrin, gentle methods of debris removal should be considered to avoid excessive damage to the tissue site.

[0045] Some debridement processes use a mechanical process to remove debris. Mechanical processes may include the use of a scalpel or other cutting tool with a thin blade to cut the debris from the tissue site. Other mechanical processes may use devices that provide a stream of particles that impact the debris to remove it in an abrasion process, or that provide a jet of high-pressure fluid that impacts the debris to remove it by water jet ablation or irrigation. Typically, the mechanical process of debriding the tissue site can be painful and may require the application of a local anesthetic. Mechanical processes also carry the risk of removing too much healthy tissue, which can cause further damage to the tissue site and delay the healing process.

[0046] Debridement can also be performed by an autolysis process. For example, an autolysis process can involve the use of enzymes and moisture produced by the tissue site to soften and liquefy necrotic tissue and debris. Typically, a dressing can be placed over the tissue site with debris so that fluids produced by the tissue site can remain in place and hydrate the debris. The autolysis process can be painless, but is slow and can take many days. Because the autolysis process is slow, it can also involve multiple dressing changes. Some autolysis processes can be paired with negative pressure therapy so that negative pressure supplied to the tissue site can pull the debris away as it is hydrated. In some cases, a manifold placed at the tissue site to distribute negative pressure across the tissue site can become blocked or clogged with debris decomposed by the autolysis process. If the manifold becomes clogged, the negative pressure may not be able to remove the debris, and the autolysis process may slow or stop.

[0047] Debridement can also be performed by adding enzymes or other agents to the tissue site that digest the tissue. Often, the placement of the enzyme and the length of time the enzyme is in contact with the tissue site must be kept strictly controlled. If the enzyme is left at the tissue site longer than necessary, the enzyme may remove too much healthy tissue, contaminate the tissue site, or be carried to other areas of the patient. If carried to other areas of the patient, the enzyme may degrade intact tissue and cause other complications.

[0048] Additionally, some dressings for treating tissue sites may include a tissue interface configured to mechanically debride the slough and relax the tissue. The tissue interface may rely primarily on mechanical action in a single direction, or along one major axis. For example, the tissue interface may collapse vertically into the wound and provide only some lateral movement to debride the tissue site under negative pressure. While tissue interfaces with mechanical action along a major axis can provide beneficial debridement procedures, it is desirable to further increase the effectiveness of tissue interfaces for debridement procedures.

[0049] These limitations and others may be addressed by a therapy system 100 capable of providing negative pressure therapy, instillation therapy, and debris disruption. In some embodiments, the therapy system 100 may provide mechanical movement at the surface of a tissue site in combination with the periodic delivery and dwell of a topical solution to aid in the solubilization of debris. For example, a negative pressure source may be fluidly coupled to the tissue site to provide negative pressure for negative pressure therapy at the tissue site. In some embodiments, a fluid source may be fluidly coupled to the tissue site to provide therapeutic fluid for instillation therapy at the tissue site. In some embodiments, the therapy system may include a tissue interface comprised of felt foam and having a plurality of oval pores. The oval pores may be preferentially aligned within the tissue interface. For example, the oval pores may be aligned within the tissue interface such that when the tissue interface is placed at the tissue site, the oval pores resist vertical compression under negative pressure and are susceptible to horizontal compression. The oval pores may allow the tissue interface to collapse horizontally, providing a second axis of mechanical action to disrupt debris at the tissue site. Following the disruption of the debris, negative pressure therapy, drip therapy, and other processes may be used to remove the debris from the tissue site. In some embodiments, therapy system 100 may be used in conjunction with other tissue removal and debridement techniques. For example, therapy system 100 may be used prior to enzymatic debridement to soften the debris. In another example, other mechanical debridements may be used to remove a portion of the debris at the tissue site, and then therapy system 100 may be used to remove the remaining debris while reducing the risk of trauma to the tissue site.

[0050] FIG. 2 is an assembled view of an example dressing 104 of FIG. 1 , illustrating additional details that may be relevant to some embodiments. In some embodiments, the dressing 104 may include a tissue interface 108. The tissue interface 108 may have a first surface 200 and a second surface 202. The first surface 200 may be configured to face the tissue site. The second surface 202 may be opposite the first surface 200. The tissue interface 108 may have a substantially uniform thickness 204 extending from the first surface 200 to the second surface 202. In some embodiments, the thickness 204 may be between about 5 mm and about 15 mm. In other embodiments, the thickness 204 may be thinner or thicker than the described range, as needed for a particular application of the dressing 104. In some embodiments, the tissue interface 108 may have a plurality of openings or holes, such as a plurality of holes 206, extending through the tissue interface 108 from the first surface 200 toward the second surface 202.

[0051] In some embodiments, the dressing 104 may include a fluid conduit 208 and a fluid port, such as a dressing interface 210. In some embodiments, the fluid conduit 208 may be a flexible tube. In some embodiments, the fluid conduit may comprise a first end 214 and a second end 216. The first end 214 of the fluid conduit 208 may be configured to be fluidly coupled to the dressing interface 210, and the second end 216 of the fluid conduit 208 may be configured to be fluidly coupled to the negative pressure source 102 (not shown).

[0052] In some embodiments, the dressing interface 210 may be an elbow connector that may be coupled to the cover 110 and fluidly coupled to the tissue interface 108, as shown for example in FIG. 2 . In some embodiments, the dressing interface 210 may be disposed over an opening 212 in the cover 110 to provide a fluid pathway between the fluid conduit 208 and the tissue interface 108. In other embodiments, the first end 214 of the fluid conduit 208 may be inserted directly through the cover 110 and into the tissue interface 108. The cover 110 may be configured to be disposed over the tissue interface 108 and create a sealed space. In some embodiments, the cover 110 may be configured to be disposed over the second surface 202 of the tissue interface 108. In some embodiments, the cover 110 may include an opening 212. In other embodiments, the opening 212 may be cut into the cover 110 before or after positioning the cover 110 on the tissue interface 108. In some embodiments, the opening 212 may be centrally located in the cover 110. In other embodiments, the location of the opening 212 may be off-center or adjacent to an end or edge of the cover 110 .

[0053] In some embodiments, the tissue interface 108 may be provided as part of an assembly or kit for forming the dressing 104. In other embodiments, the tissue interface 108 may be provided separately from the cover 110, fluid conduits 208, and dressing interface 210 for assembling the dressing 104 at the time of use.

[0054] If not already configured, the dressing interface 210 may be placed over the opening 212 and attached to the cover 110. A first end 214 of the fluid conduit 208 may be fluidly coupled to the dressing interface 210, and a second end 216 of the fluid conduit 208 may be fluidly coupled to the negative pressure source 102.

[0055] 3 is a plan view of the tissue interface 108 of FIG. 2 showing additional details that may be relevant to some embodiments. In some embodiments, the plurality of holes 206 may be dispersed across the first surface 200 of the tissue interface 108. The plurality of holes 206 may be uniformly distributed. In other embodiments, the plurality of holes 206 may be preferentially located on a portion of the tissue interface 108.

[0056] In some embodiments, the plurality of holes 206 extending into the tissue interface 108 may form a wall 302. In some embodiments, the outer surface of the wall 302 may be parallel to the plane of the tissue interface 108. In some embodiments, the inner surface of the wall 302 may be generally perpendicular to the first surface 200 and the second surface 202 of the tissue interface 108. One or more inner surfaces of the wall 302 may form the perimeter 304 of each hole. In some embodiments, the holes 206 may have a uniform shape. In other embodiments, each hole 206 of the plurality of holes 206 may be polygonal, oval, or irregular in shape. In some embodiments, the holes 206 may have an average effective diameter of about 5 mm to about 20 mm. Preferably, each hole 206 of the plurality of holes 206 may have an average effective diameter of about 10 mm.

[0057] In some embodiments, the tissue interface 108 may have a length 306 and a width 308. The length 306 of the tissue interface 108 may be between about 180 mm and about 256 mm. The width 308 of the tissue interface 108 may be between about 125 mm and about 150 mm. In some embodiments, the tissue interface 108 may have a contraction axis 310 positioned parallel to the length 306. The contraction axis 310 may also be positioned parallel to the first surface 200 and the second surface 202. In some embodiments, the contraction axis 310 may be used to indicate a desired direction of contraction of the tissue interface 108. For example, the desired contraction direction of the tissue interface 108 may be perpendicular to the contraction axis 310. In other embodiments, the desired contraction direction may be parallel to the contraction axis 310. In other embodiments, the desired contraction direction may be at a non-perpendicular angle to the contraction axis 310. In other embodiments, the tissue interface 108 may not have a desired contraction direction.

[0058] Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3, showing further details that may be relevant to some embodiments. In some embodiments, the plurality of holes 206 may extend through the thickness 204 of the tissue interface 108 from the first surface 200 to the second surface 202. The plurality of holes 205 may have a depth that is substantially equal to the thickness 204 of the tissue interface 108. In other embodiments, the plurality of holes 206 may comprise a plurality of blind holes or openings. For example, the plurality of holes 206 may extend from the first surface 200 toward the second surface 202 to a depth that is less than the thickness 204 of the tissue interface 108. The depth of the plurality of blind holes or openings may be between about 5 mm and about 15 mm.

[0059] FIG. 5 is a detailed view of the tissue interface 108 of FIG. 4 , showing additional details that may be relevant to some embodiments. The tissue interface 108 may be formed from a dressing material such as a foam. For example, cellular foam, open-cell foam, reticulated foam, or a porous tissue mass may be used to form the tissue interface 108. The tissue interface 108 may include a plurality of pores 500. In some embodiments, each of the pores 500 in the tissue interface 108 may have a pore size or average effective diameter ranging from about 60 microns to about 2000 microns. In other embodiments, the pores 500 may have a pore size or average effective diameter ranging from about 400 microns to about 600 microns. The tensile strength of the tissue interface 108 may also be varied according to the needs of a prescribed therapy. For example, the tensile strength of a foam may be increased for instillation of a topical treatment solution. The 25% compressive load deflection of the tissue interface 108 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 tissue interface 108 may be at least 10 pounds per square inch. The tissue interface 108 may have a tear strength of at least 2.5 pounds per inch. In one non-limiting example, the tissue interface 108 may be an open-cell reticulated polyurethane foam such as VAC® GRANUFOAM™ available from Kinetic Concepts, Inc. (San Antonio, Texas); in other embodiments, the tissue interface 108 may be an open-cell reticulated polyurethane foam such as VACVERAFLO™ dressing available from Kinetic Concepts, Inc. (San Antonio, Texas). In other embodiments, the tissue interface 108 may be formed of a non-reticulated open-cell foam.

[0060] In some embodiments, the tissue interface 108 may be formed from a foam that is mechanically or chemically compressed, often as part of a thermoforming process, to increase the foam's density at ambient pressure. Mechanically or chemically compressed foams are sometimes referred to as compressed foams or felted foams. Felted foams can be characterized by a hardness factor (FF), which indicates the compression of the foam. The hardness factor of a felted foam may be specified as the ratio of its original thickness to its final thickness. For example, a hardness factor (FF) of 5 may refer to a compressed foam having a density at ambient pressure that is five times greater than the density of the same foam at ambient pressure in an uncompressed state. Generally, compressed or felted foams may have a hardness factor greater than 1. The degree of compression may affect the physical properties of the felted foam. For example, a felted foam has a higher effective density than a foam of the same material that has not been felted. The felting process may also affect the interaction of fluids with the foam. For example, as density increases, compressibility or crushability may decrease. Thus, foams with different compressibility or crushability may have different hardness factors. In some exemplary embodiments, the hardness factor may range from about 2 to about 10, preferably from about 3 to about 5. For example, the hardness factor of the felted foam of tissue interface 108 may, in some embodiments, be about 5. There is a general linear relationship between hardness level, density, pore size (or pores per inch), and compressibility. For example, a foam felted to a hardness factor of 3 exhibits a three-fold density increase and will compress to about one-third of its original thickness.

[0061] In some embodiments, the compressed foam may be a compressed VAC® GRANUFOAM™ dressing, which has a density of about 0.03 grams per centimeter in its uncompressed state. 3 (g / cm 3When a VAC® GRANUFOAM™ dressing is compressed to have a Hardness Factor (FF) of 5, the VAC® GRANUFOAM™ dressing may have a density of about 0.15 g / cm 3 VAC® VERAFLO™ Dressings can also be compressed to form compressed foams with a Hardness Factor (FF) of up to 5. For example, VAC® VERAFLO™ has a hardness of approximately 1.7 lbs / ft. 3 (lb / ft 3 ) density or 0.027 grams / cm 3 (g / cm3) and approximately 2.1 lb / ft 3 or 0.034 g / cm 3 When a VAC® VERAFLO™ dressing is compressed to have a Hardness Factor (FF) of 5, the VAC® VERAFLO™ dressing may have a density of about 0.135 g / cm 3 ~Approx. 0.17g / cm 3 It can be compressed until

[0062] Felting involves a thermoforming process that permanently compresses foam to increase its density while maintaining interconnected pathways. For example, felting may be performed by applying heat and pressure to a porous dressing, such as a foam material. Some methods may involve compressing a foam blank between one or more heated platens or dies (not shown) at a specific temperature for a specific period of time. In some embodiments, the direction of compression may be parallel to the thickness of the foam block. For example, the direction of force applied to the dressing blank may be parallel to the thickness and perpendicular to the surface on which the force acts. In other embodiments, the direction of compression may be perpendicular to the thickness of the dressing blank. For example, the direction of force applied to the dressing foam blank may be parallel to the thickness and perpendicular to the surface on which the force acts.

[0063] The compression period can range from 10 minutes to 24 hours, although this period may be longer or shorter depending on the particular type of dressing used. Additionally, in some embodiments, the temperature may range from 120°C to 260°C. Generally, the lower the platen temperature, the longer the dressing must be held in a compressed state. After the specified period of time has elapsed, the pressure and heat form a felt structure or surface on or within the dressing or portion of the dressing.

[0064] Generally, when compressed foam is subjected to negative pressure, it exhibits less deformation than a similar uncompressed foam. When the tissue interface 108 is formed from compressed foam, the thickness 204 of the tissue interface 108 may deform less than when the tissue interface 108 is formed from an equivalent uncompressed foam. The reduced deformation may be caused by an increased stiffness, as reflected by the hardness factor (FF). When subjected to the stress of negative pressure, the tissue interface 108 formed from compressed foam may flatten less than a tissue interface 108 formed from uncompressed foam. Thus, when negative pressure is applied to the tissue interface 108, the stiffness of the tissue interface 108 in a direction parallel to the thickness 204 of the tissue interface 108 allows the tissue interface 108 to be more flexible or more compressible in other directions, such as directions perpendicular to the thickness 204. The foam material used to form the compressed foam may be either hydrophobic or hydrophilic. The foam material used to form the compressed foam may also be either reticulated or non-reticulated.

[0065] The density of the foam generally increases with felting. In some embodiments, contact with the heated press platens during the felting process may also result in a density gradient, with higher density at the surface and smaller pore size at the surface. In some embodiments, the felt structure may be relatively smoother than any unfinished or unfelted surface or portion of the dressing. Furthermore, the pores 500 within the felt structure may be smaller than the pores throughout any unfinished or unfelted surface or portion of the dressing. In some examples, the felt structure may be applied to all surfaces or portions of the dressing. Furthermore, in some examples, the felt structure may extend into or through the entire thickness of the dressing, such that all of the dressing is felted.

[0066] The pore size of the foam material can vary depending on the needs of the tissue interface 108 and the amount of compression of the foam. For example, in some embodiments, the pores of the uncompressed foam can have a pore size ranging from about 400 micrometers to about 600 micrometers. When the same foam is compressed, the pores of the compressed foam can have a smaller pore size than when the foam is in an uncompressed state.

[0067] The felting process may change certain properties of the original material, including pore shape and / or size, elasticity, density, and density distribution. For example, the struts defining the pores 500 in the foam may be deformed during the felting process. The deformed struts may reduce the elasticity of the foam. The deformed struts may also cause the pore shape to flatten. For example, an unfelted foam may have pores that are substantially circular or spherical in shape. By felting the foam, the pores 500 of the tissue interface 108 may have a non-circular shape. In some embodiments, each of the pores 500 may have a generally elliptical or oval shape.

[0068] The struts and pore shape deformation may be applied preferentially. For example, the pores 500 may be deformed such that the shape of each pore 500 is oriented in a particular direction within the tissue interface 108. In some embodiments, the orientation of the pores 500 may be controlled by felting the dressing. For example, the pores 500 may be deformed such that the deformation of the pores 500 is oriented relative to the surface of the tissue interface 108 that is intended to contact the tissue site. In some embodiments, the pores 500 may be preferentially deformed relative to the first surface 200. For example, the dressing blank that forms the tissue interface 108 may be felted by applying heat and compression to the thickness 204. The direction of the force applied to the dressing is parallel to the first surface 200 of the tissue interface 108.

[0069] Figure 6 is a detail view illustrating further details that may be associated with some embodiments of the plurality of pores 500 of Figure 5. In Figure 6, a single pore of the plurality of pores 500 of the tissue interface 108 is shown. In some embodiments, the tissue interface 108 may have a first axis 602 and a second axis 603. The first axis 602 may be parallel to the thickness 204 and may be perpendicular to the first surface 200 and the second surface 202 of the tissue interface 108. The second axis 603 may be perpendicular to the first axis 602 and may be parallel to the first surface 200 and the second surface 202 of the tissue interface 108.

[0070] In some embodiments, each of the plurality of pores 500 may be oriented at an angle relative to the first surface 200 and the second surface 202 of the tissue interface 108. For example, each pore 500 of the plurality of pores 500 may have a major axis 600 extending through the center of the pore 500. The major axis 600 may be oriented parallel to the first axis 602 and perpendicular to the second axis 603. In some embodiments, the major axis 600 may be oriented perpendicular to the first surface 200 and the second surface 202 and parallel to the thickness 204. In some embodiments, the major axis 600 may be oriented at an angle relative to the second axis 603. For example, the angle between the second axis 603 and the major axis 600 may be approximately 90°. In some embodiments, each pore 500 of the plurality of pores 500 may have a pore length 606 extending generally parallel to the major axis 600 and a pore width 608 extending generally perpendicular to the major axis 600. In some embodiments, the pore length 606 of the plurality of pores 500 may be greater than the pore width 608.

[0071] The pores 500 may be oriented by the manufacturing process. During felting, a force 604 may be applied to the foam blank of the dressing. The force 604 may change the shape of the pores 500 by forcing surfaces of the pores 500 perpendicular to the force 604 toward each other and surfaces parallel to the force 604 away from each other. As a result, the pores 500 are stretched parallel to the first axis 602 and compressed parallel to the second axis 603. Heat applied during the felting process may set the pores 500 to the shape formed by the force 604. In other embodiments, the force 604 may be applied at a non-perpendicular angle to the first axis 602, causing the pores 500 to compress at an angle relative to the first axis 602 and stretch at an angle relative to the first axis 602. In general, the pore width 608 of the pore 500 may be parallel to the direction of the force 604 and the pore length 606 of the pore 500 may be perpendicular to the direction of the force 604 .

[0072] In some embodiments, the orientation of the plurality of pores 500 may allow the plurality of pores 500 to compress more in a direction parallel to the second axis 603 and resist compression in a direction parallel to the first axis 602. For example, each of the plurality of pores 500 may be configured to contract in a direction perpendicular to the major axis 600. In some embodiments, each of the plurality of pores 500 may be configured to contract in a direction parallel to the first surface 200 and the second surface 202. In some embodiments, each of the plurality of pores 500 may be configured to contract in all directions toward the major axis 600. In some embodiments, the pores 500 may resist collapse more in a direction parallel to the major axis 600 than in a direction perpendicular to the major axis 600. As a result, the tissue interface 108 formed from the pores 500 may collapse laterally under negative pressure. See, for example, the experimental data below.

[0073] The following samples were provided: three unfelted GRANUFOAM blocks with a starting size of 25 mm (height) x 25 mm (width) and having generally spherical pores; three 3X felt (e.g., hardness factor of 3) GRANUFOAM blocks with a starting size of 25 mm (height) x 25 mm (width) and having oval pores with their major axes oriented generally parallel to the thickness (e.g., height); and three 5X felt (e.g., hardness factor of 5) GRANUFOAM blocks with a starting size of 25 mm (height) x 25 mm (width) and having oval pores with their major axes oriented generally parallel to the thickness (e.g., height). A negative pressure of approximately -125 mmHg was applied to all three samples, and height and width measurements under the applied negative pressure were recorded as follows:

[0074] TIFF0007757384000001.tif46170

[0075] In some embodiments, felt foams having oval pores with their major axes oriented generally parallel to the thickness (e.g., height) may shrink in thickness by about half or less under applied negative pressure compared to similar non-felted foams. For example, felt foams having oval pores with their major axes oriented generally parallel to the thickness may shrink in thickness by about half to one-fifth the amount under applied negative pressure compared to similar non-felted foams. In some embodiments, felt foams having oval pores with their major axes oriented generally parallel to the thickness may have a lateral shrinkage under applied negative pressure that is about 16 times greater or greater than that of similar non-felted foams. For example, felt foams having oval pores with their major axes oriented generally parallel to the thickness may have a lateral shrinkage under applied negative pressure that is about 16 to 24 times greater than that of similar non-felted foams.

[0076] In some embodiments, the orientation of the oval pores may provide resistance to thickness contraction, maintaining a surface area that transmits a higher lateral force under applied negative pressure compared to the lateral force from a similar non-felted foam. For example, a 3X felt foam (e.g., a foam with a hardness factor of 3) with oval pores oriented generally parallel to the thickness may have approximately 30-70% better lateral force under applied negative pressure than a similar non-felted foam. Similarly, if a particular lateral force is desired under applied negative pressure, that amount of lateral force may be generated using less negative pressure when a felt foam with oval pores oriented generally parallel to the thickness is used instead of a similar non-felted foam.

[0077] FIG. 7 is a plan view illustrating further details that may be relevant to some embodiments of the perforations 206 of the tissue interface 108 of FIG. 3 . In FIG. 7 , a single circular perforation 206 is shown. The perforation 206 may include a center 704 and a periphery 706. The perforation 206 may have a perforation shape factor (PSF). The perforation shape factor (PSF) may represent the orientation of the perforation 206 relative to the first orientation line 700 and the second orientation line 702. Generally, the perforation shape factor (PSF) is the ratio of half the maximum length of the perforation 206 parallel to the desired contraction direction to half the maximum length of the perforation 206 perpendicular to the desired contraction direction. For purposes of illustration, the desired contraction direction is parallel to the second orientation line 702. The desired contraction direction may be indicated by a lateral force 708. For reference, hole 206 may have an X-axis 710 that extends through center 704 and parallel to first bearing line 700, and a Y-axis 712 that extends through center 704 and parallel to second bearing line 702. A perforation shape factor (PSF) of hole 206 may be defined as the ratio of a line segment 714 on Y-axis 712 that extends from center 704 to the periphery 706 of hole 206 to a line segment 716 on X-axis 710 that extends from center 704 to the periphery 706 of hole 206. For example, if line segment 714 has a length of 2.5 mm and line segment 716 has a length of 2.5 mm, then the shape factor (PSF) is 1. In other embodiments, the holes 206 may have other shapes (e.g., oval, hexagonal, square, triangular, or amorphous or irregular shapes) and orientations and may be oriented with respect to the first and second orientation lines 700, 702 such that the perforation shape factor (PSF) may be in the range of about 0.5 to about 1.10.

[0078] FIG. 8 is a plan view showing further details of the plurality of holes 206 of the tissue interface 108 of FIG. 3. As shown in FIG. 8, the tissue interface 108 may include a plurality of holes 206 aligned in parallel rows to form an array. The array of holes 206 may include a first row 802 of holes 206, a second row 804 of holes 206, and a third row 806 of holes 206. In some embodiments, the width of the wall 302 between the perimeters 304 of adjacent holes 206 in a row, such as the first row 802, may be about 13 mm to about 15 mm. In some embodiments, the width of the wall 302 between the perimeters 304 of adjacent holes may preferably be 14 mm.

[0079] In some embodiments, a line connecting the centers of adjacent rows may form a strut angle (SA) with the first orientation line 700. For example, a first hole 206A in the first row 802 may have a center 704A, and a second hole 206B in the second row 804 may have a center 704B. A strut line 808 may connect the centers 704A and 704B. The strut line 808 may form an angle 810 with the first orientation line 700. The angle 810 may be the strut angle (SA) of the tissue interface 108. In some embodiments, the strut angle (SA) may be less than about 90°. In other embodiments, the strut angle (SA) may be between about 30° and about 70° relative to the first orientation line 700. In other embodiments, the strut angle (SA) may be about 66° from the first orientation line 700. Generally, as the strut angle (SA) decreases, the stiffness of the tissue interface 108 in a direction parallel to the first orientation line 700 may increase. Increasing the stiffness of the tissue interface 108 parallel to the first orientation line 700 may increase the compressibility of the tissue interface 108 perpendicular to the first orientation line 700. As a result, when a negative pressure is applied to the tissue interface 108, the tissue interface 108 may become more flexible or more compressible in a direction perpendicular to the first orientation line 700. By increasing the compressibility of the tissue interface 108 in a direction perpendicular to the first orientation line 700, the tissue interface 108 may collapse to apply a lateral force 708 to the tissue site, as described in more detail below.

[0080] In some embodiments, the centers 704 of the holes 206 in alternating rows, e.g., center 704A of a first hole 206A in the first row 802 and center 704C of a hole 206C in the third row 806, can be spaced apart from one another parallel to the second azimuth line 702 by a length 812. In some embodiments, length 812 can be greater than the effective diameter of the holes 206. When the centers 704 of the holes 206 in alternating rows are separated by length 812, the outer surface of the wall 302 parallel to the first azimuth line 702 can be considered continuous. Generally, the outer surface of the wall 302 can be continuous if the outer surface of the wall 302 does not have discontinuities or breaks between the holes 206. In some embodiments, length 812 can be between about 4 mm and about 6 mm.

[0081] In some embodiments, the pores 206 may be formed during molding of the tissue interface 108. In other embodiments, the pores 206 may be formed by cutting, melting, drilling, or vaporizing the tissue interface 108 after the tissue interface 108 is formed. For example, the pores 206 may be formed in the tissue interface 108 by laser ablating a compressed foam of the tissue interface 108. In some embodiments, the pores 206 may be formed such that the inner surfaces of the walls 302 of the pores 206 are parallel to the thickness 204. In other embodiments, the pores 206 may be formed such that the inner surfaces of the walls 302 of the pores 206 form an angle other than perpendicular with the first surface 200. In still other embodiments, the inner surfaces of the walls 302 of the pores 206 may taper toward the center 704 of the pores 206 to form a cone, pyramid, or other irregular through-hole shape. If the inner surfaces of the walls 302 of the pores 206 are tapered, the pores 206 may have a height that is less than the thickness 204 of the tissue interface 108.

[0082] FIG. 9 is a plan view showing further details of the tissue interface 108 of FIG. 3 in a contracted state. When the tissue interface 108 is positioned over a tissue site, the tissue interface 108 may generate a lateral force 708 perpendicular to the contraction axis 310, causing the tissue interface 108 to contract as shown. In operation, negative pressure is supplied to the sealed space by the negative pressure source 102. In response to the supply of negative pressure, the tissue interface 108 contracts from the relaxed position shown in FIG. 3 to the contracted position shown in FIG. 9. When the negative pressure is removed, for example, by venting the negative pressure from the sealed space, the tissue interface 108 expands back to the relaxed position. As the tissue interface 108 cycles between the contracted position of FIG. 3 and the relaxed position of FIG. 9, the first surface 200 of the tissue interface 108 may disrupt debris at the tissue site by scraping the debris from the tissue site. The edges of the holes 206 formed by the first surface 200 and the inner or cross-sectional surface of the wall 302 can form cutting edges that can disrupt debris at the tissue site and allow the debris to exit through the holes 206. In some embodiments, the cutting edges are defined by the perimeter 304 where each hole 206 intersects the first surface 200.

[0083] FIG. 10 is a detailed view illustrating additional details that may be associated with the plurality of pores 500 of the tissue interface 108 of FIG. 5 in a contracted state or position. In response to the application of negative pressure, the plurality of pores 500 may collapse from the relaxed position shown in FIG. 5 to the contracted position shown in FIG. 10. For example, the plurality of pores 500 may be configured to collapse in a direction parallel to the first surface 200 and the second surface 202 of the tissue interface 108, as indicated by the lateral force 708. The ovoid shape of the plurality of pores 500 combined with the plurality of holes 206 allows the tissue interface 108 to contract laterally and debride tissue, as indicated by the lateral force 708. In some embodiments, the lateral force 708 may be perpendicular to the contraction axis 310. In yet other embodiments, the lateral force 708 may be generated at an angle relative to the contraction axis 310.

[0084] 11 is a cross-sectional view of a portion of the dressing 104 of FIG. 2 showing further details that may be relevant to some embodiments. The tissue interface 108 may be positioned at a tissue site 1102 having debris 1104 covering subcutaneous tissue 1106. For example, a clinician may position the tissue interface 108 at the tissue site 1102. In some embodiments, the length 306 and width 308 of the tissue interface 108 may be larger than the opening in the tissue site 1102. The tissue interface 108 may be sized to allow the tissue interface 108 to pass through the opening in the tissue site 1102 and be positioned adjacent to the debris 1104. Sizing may include removing a portion of the tissue interface 108, for example, by cutting, tearing, melting, dissolving, vaporizing, or otherwise separating the portion of the tissue interface 108 from the remainder of the tissue interface 108. Following sizing and placement of the tissue interface 108 at the tissue site 1102, the cover 110 may be placed over the tissue interface 108 to provide a sealed environment for the application of negative pressure or drip therapy.

[0085] FIG. 12 is a cross-sectional view of a portion of the dressing 104 of FIG. 2 during negative pressure therapy, showing further details that may be relevant to some embodiments. For example, FIG. 12 may illustrate a time when the pressure within the sealed environment may be negative at approximately −125 mmHg. In response to the application of negative pressure, the pores 500 of the tissue interface 108, oriented such that the pore lengths 606 of the pores 500 are parallel to the thickness 204 and the pore widths 608 of the pores 500 are parallel to the first surface 200, may resist collapse. Accordingly, the tissue interface 108 may not be compressed or may be minimally compressed. Preferably, the thickness 204 remains substantially the same. In some embodiments, the thickness 204 of the tissue interface 108 during negative pressure therapy may be slightly smaller than the thickness 204 of the tissue interface 108 when the pressure within the sealed environment is approximately ambient pressure.

[0086] In some embodiments, the negative pressure in the sealed environment can create concentrated stresses in the tissue interface 108 and the debris 1104 adjacent to the holes 206 in the tissue interface 108. The concentrated stresses can cause macro-deformations in the debris 1104 and the subcutaneous tissue 1106, drawing portions of the debris 1104 and subcutaneous tissue 1106 into the holes 206. For example, when the holes 206 collapse under negative pressure in a direction parallel to the first surface 200 and the second surface 202, portions of the subcutaneous tissue 1106 and debris 1104 may be drawn into the holes 206 by a pinching action. Additionally, because the tissue interface 108 resists compression in a direction parallel to the thickness 204, portions of the subcutaneous tissue 1106 and debris 1104 may be drawn into the thickness 204 of the tissue interface 108 under negative pressure.

[0087] In some embodiments, the pores 206 in the tissue interface may form macro-pressure points at the debris 1104 and subcutaneous tissue 1106 where they contact the first surface 200 of the tissue interface 108, causing tissue puckering and a nodule 1202 in the debris 1104 and subcutaneous tissue 1106. The height of the nodule 1202 above the surrounding tissue may be selected to maximize the disruption of the debris 1104 and minimize damage to the subcutaneous tissue 1106 or other desired tissue. Generally, pressure within a sealed environment may exert a force proportional to the area over which the pressure is applied. The pores 206 in the tissue interface 108 may offer less resistance to the application of pressure than the walls 302 of the tissue interface 108, so force may be concentrated. In response to the force generated by the pressure at the pores 206, the debris and subcutaneous tissue 1106 forming the nodule 1202 may be drawn into the pores 206 until the force exerted by the pressure is balanced by the counterforce of the debris 1104 and subcutaneous tissue 1106. In some embodiments where negative pressure within the sealed environment may cause tearing, the depth of the holes 206 may be selected to limit the height of the bump 1202 above the surrounding tissue. In some embodiments, the height of the bump 1202 may be limited to a height less than the depth of the holes 206. In an exemplary embodiment, the depth of the holes 206 may be approximately 8 mm. During application of negative pressure, the height of the bump 1202 may be limited to between approximately 2 mm and approximately 8 mm. Controlling the depth of the holes 206 and thereby the height of the bump 1202 may control the invasiveness and tearing of the fracture on the debris 1104.

[0088] In some embodiments, the formation of the lump 1202 may keep the debris 1104 in contact with the tissue interface 108 during negative pressure therapy. For example, the lump 1202 may contact the sidewall of the hole 206 in the tissue interface 108. In some embodiments, the formation of the lump 1202 may lift the debris 1104 and particulate matter from the surrounding tissue and act like a piston, moving the debris 1104 from the sealed environment towards the cover 110.

[0089] In response to the sealing environment returning to ambient pressure, the nub 1202 can move away from the hole 206 and return to the position shown in FIG. 11 . In some embodiments, repeated application of negative pressure and drip therapy while the tissue interface 108 is positioned over the debris 1104 can break down the debris 1104, allowing it to be removed during a dressing change. In other embodiments, the tissue interface 108 can break down the debris 1104 so that it can be removed by the negative pressure. In still other embodiments, the tissue interface 108 can break down the debris 1104 and aid in the removal of the debris 1104 during the debridement process. With each cycle of therapy, the tissue interface 108 can form a nub 1202 in the debris 1104. The formation and release of the nub 1202 by the tissue interface 108 during therapy can break down the debris. Each subsequent cycle of therapy can increase the breakdown of the debris 1104.

[0090] The destruction of the debris 1104 may be caused, at least in part, by a concentrated force applied to the debris 1104 by the holes 206 and walls 302 of the tissue interface 108. The force applied to the debris 1104 may be a function of the negative pressure provided to the sealed environment and the area of ​​each hole 206. For example, if the negative pressure provided to the sealed environment is approximately −125 mmHg and the diameter of each hole 206 is approximately 5 mm, the force applied at each hole 206 is approximately 0.07 lbs. If the diameter of each hole 206 is increased to approximately 8 mm, the force applied at each hole 206 may increase by up to six times. In general, the relationship between the diameter of each hole 206 and the applied force at each hole 206 is not linear, but may increase exponentially with increasing diameter.

[0091] In some embodiments, the negative pressure applied by the negative pressure source 102 may be rapidly cycled. For example, the negative pressure may be supplied for several seconds and then exhausted for several seconds, causing pulsations of negative pressure in the sealed environment. The pulsations of negative pressure may cause the nub 1202 to pulsate, causing further disruption of the debris 1104.

[0092] In some embodiments, the cyclical application of drip therapy and negative pressure therapy can cause micro-floating. For example, negative pressure may be applied to the sealed environment during a negative pressure therapy cycle. Following completion of a negative pressure therapy cycle, a drip fluid may be provided during the drip therapy cycle. The drip fluid can suspend the tissue interface 108 relative to the debris. When suspended, the tissue interface 108 can change position relative to the position it occupied during the negative pressure therapy cycle. The change in position can cause the tissue interface 108 to engage a slightly different portion of the debris 1104 during the next negative pressure therapy cycle, assisting in the destruction of the debris 1104.

[0093] Methods of manufacturing a dressing for a tissue site are also described herein, and some exemplary embodiments include providing a dressing having a surface configured to contact the tissue site. The dressing may have a plurality of pores. In some embodiments, the dressing may include an open-cell reticulated foam. The method may further include applying a compressive force to the dressing at an angle relative to the surface to cause permanent deformation of the plurality of pores. In some embodiments, the angle may be approximately 90°. In some embodiments, applying the compressive force to the dressing may include densifying the dressing. In some embodiments, the method may further include forming a plurality of pores in the dressing. The plurality of pores may extend from the surface into the dressing. In some embodiments, the plurality of pores may be formed in the dressing after applying the compressive force to the dressing. In some embodiments, the method may further include heating the dressing.

[0094] In some embodiments, causing permanent deformation of the plurality of pores may include forming a plurality of compressed pores. Forming the plurality of compressed pores may include compressing the pores from a generally circular shape to a generally oval shape. In some embodiments, the method may further include orienting major axes of the oval pores perpendicular to the surface. In some embodiments, the plurality of compressed pores may be configured to collapse from a relaxed position to a contracted position in response to application of negative pressure. In some embodiments, the plurality of compressed pores may be configured to collapse in a direction parallel to the surface.

[0095] Alternatively, other exemplary embodiments may describe a system for providing negative pressure therapy to a tissue site. The system may include a tissue interface, a sealing member configured to be disposed across the tissue interface and create a sealed space, and a negative pressure source fluidly coupled to the sealed space. In some embodiments, the sealing member may include a polymer film. In some embodiments, the sealing member may be configured to be bonded to a second surface of the tissue interface using an adhesive. The tissue interface may include a first surface configured to face the tissue site, a second surface opposite the first surface, a thickness extending from the first surface to the second surface, and a plurality of pores, each having an oval shape oriented at an angle relative to the first surface. In some embodiments, the angle may be approximately 90°. In some embodiments, the plurality of pores may be configured to contract in a direction parallel to the first and second surfaces.

[0096] Also described herein are tissue interfaces for treating a tissue site, which can be formed by a process including providing a dressing and applying a compressive force to the dressing. The dressing can have a surface configured to contact the tissue site and a plurality of pores. The compressive force can be applied to the dressing at an angle relative to the surface. The compressive force can also cause permanent deformation of the plurality of pores. In some embodiments, applying the compressive force to the dressing can include compressing the dressing from a first thickness to a second thickness. In some embodiments, the first thickness can be greater than the second thickness.

[0097] Methods for treating a tissue site are also described herein. Some exemplary embodiments include applying a tissue interface to the tissue site. The tissue interface may include a first surface configured to face the tissue site, a second surface opposite the first surface, a thickness extending from the first surface to the second surface, and a plurality of pores having an elliptical shape and a major axis oriented perpendicular to the first and second surfaces. In some embodiments, the plurality of pores are configured to contract in a direction parallel to the first and second surfaces. The method further includes covering the tissue interface with a cover to form a sealed space adjacent to the tissue interface, fluidly coupling a fluid conduit to the tissue interface, fluidly coupling a negative pressure source to the fluid conduit, applying negative pressure from the negative pressure source through the fluid conduit to the tissue interface, and contracting the tissue interface from a first width to a second width in response to the application of negative pressure to the tissue interface. The second width may be smaller than the first width.

[0098] The systems, devices, and methods described herein can provide significant advantages. For example, the embodiments described herein provide a tissue interface that can contract laterally while resisting vertical compression. Resistance to lateral contraction and vertical compression can provide improved wound healing and cleansing. For example, the tissue interface can contract in a direction parallel to the surface of the tissue site to relax the slough and provide tissue debridement.

[0099] While illustrated 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 within the scope of the appended claims. Furthermore, the description of various alternatives using terms such as "or" does not require mutual exclusivity unless clearly required by context, and the indefinite articles "a" or "an" do not limit reference to a single case unless clearly required by 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 104, the container 106, or both may be excluded or separated from other components for manufacture or sale. In other exemplary configurations, the controller 112 may also be manufactured, configured, assembled, or sold independently of other components.

[0100] The appended claims recite the novelty and inventive step of the above-described subject matter, but 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, comprising: a tissue interface; a first surface configured to face the tissue site; and a second surface opposite the first surface; and a thickness extending from the first surface to the second surface; a plurality of pores having an elliptical shape and a major axis oriented perpendicular to the first surface and the second surface; A dressing comprising a tissue interface including:

2. The dressing of claim 1 , wherein the plurality of pores are configured to contract in a direction parallel to the first surface and the second surface.

3. 3. The dressing of claim 1 or 2, further comprising a dressing length and a dressing width, said major axis being oriented perpendicular to said dressing length and parallel to said thickness.

4. 4. The dressing of claim 1, wherein the plurality of pores are configured to contract in a direction perpendicular to the major axis.

5. A dressing according to claim 1 or any one of claims 2 to 4, wherein the tissue interface comprises a felt foam.

6. 6. The dressing of claim 5, wherein the felt foam is felted to a hardness modulus of 2-10.

7. The felt foam has a density of about 0.027 to about 0.034 g / cm ３ 6. The dressing of claim 5 having a density of

8. 8. A dressing according to claim 1 or any one of claims 2 to 7, further comprising a plurality of holes extending from the first surface to the second surface.

9. 1. A system for providing negative pressure therapy to a tissue site, comprising:

1. An organizational interface, comprising: a first surface configured to face the tissue site; and a second surface opposite the first surface; and a thickness extending from the first surface to the second surface; a plurality of pores, each of the plurality of pores having an ovoid shape and a major axis of each of the plurality of pores oriented at an angle of 90° with respect to the first surface; an organizational interface, a sealing member disposed across the tissue interface and configured to create a sealed space; a negative pressure source fluidly coupled to the sealed space; A system comprising:

10. The system of claim 9 , wherein the plurality of pores are configured to contract in a direction parallel to the first surface and the second surface.

11. 11. The system of claim 9 or claim 10, wherein the sealing member is configured to be bonded to the second surface of the tissue interface with an adhesive.

12. The system of claim 9 or any one of claims 10-11, wherein the sealing member comprises a polymer film.

13. 1. A method of manufacturing a tissue interface for treating a tissue site, the method comprising: providing a dressing having a surface configured to contact the tissue site, the dressing having a plurality of pores; applying a compressive force to the dressing at an angle to the surface, the compressive force causing a permanent deformation of the plurality of pores from a generally circular shape to a plurality of compressed pores having an oval shape, the major axes of the plurality of compressed pores being perpendicular to the surface; A method comprising:

14. 14. The method of claim 13, further comprising heating the dressing to a temperature of from about 120 degrees Celsius (°C) to about 260°C.

15. The method of claim 13 , wherein the plurality of compressed pores are configured to collapse from a relaxed position to a contracted position in response to application of negative pressure.

16. The method of claim 13 , wherein the plurality of compressed pores are configured to collapse in a direction parallel to the surface.

17. 17. The method of claim 13 or any one of claims 14 to 16, wherein applying the compressive force to the dressing comprises compressing the dressing from a first thickness to a second thickness.

18. 18. The method of claim 13 or any one of claims 14 to 17, wherein providing a dressing comprises providing an open-cell reticulated foam.

19. 19. The method of claim 13 or any one of claims 14 to 18, further comprising forming a plurality of holes in the dressing, the plurality of holes extending from the surface into the dressing.

20. 20. The method of claim 19, wherein the plurality of holes are formed in the dressing after applying the compressive force to the dressing.

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