EP4791330A1

EP4791330A1 - Dressing for negative-pressure therapy with transparent layers

Info

Publication number: EP4791330A1
Application number: EP24791520.0A
Authority: EP
Inventors: Christopher D. BREACH
Original assignee: Solventum Intellectual Properties Co
Current assignee: Solventum Intellectual Properties Co
Priority date: 2023-10-13
Filing date: 2024-09-26
Publication date: 2026-08-19
Also published as: WO2025078906A1

Abstract

An apparatus for treating a tissue site with negative pressure may include a first polymer film having a plurality of first perforations. A primary manifold may be adjacent to the first polymer film. The primary manifold may include a plurality of primary nodes and a plurality of links. The primary nodes and the links may be interconnected to define a grid of windows that are transparent. Further, a second polymer film may be adjacent to the primary manifold. The second polymer film may have a plurality of second perforations. The first polymer film and the second polymer film are bonded together in at least a center window of the primary manifold.

Description

DRESSINGS FOR NEGATIVE-PRESSURE THERAPY WITH TRANSPARENT LAYERS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 63/590,023, filed on October 13, 2023, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] This disclosure relates generally to tissue treatment systems and more particularly, but without limitation, to dressings for tissue treatment and methods for tissue treatment with negative pressure.

BACKGROUND

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

[0004] There is also widespread acceptance that cleansing a tissue site can be highly beneficial for new tissue growth. For example, a wound or a cavity can be washed out with a liquid solution for therapeutic purposes. These practices are commonly referred to as “irrigation” and “lavage” respectively. “Instillation” is another practice that generally refers to a process of slowly introducing fluid to a tissue site and leaving the fluid for a prescribed period of time before removing the fluid. For example, instillation of topical treatment solutions over a wound bed can be combined with negative-pressure therapy to further promote wound healing by loosening soluble contaminants in a wound bed and removing infectious material. As a result, soluble bacterial burden can be decreased, contaminants removed, and the wound cleansed.

[0005] While the clinical benefits of negative-pressure therapy and/or instillation therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients. SUMMARY

[0006] New and useful systems, apparatuses, and methods for treating tissue in a negative-pressure therapy environment are set forth in the appended claims. Illustrative embodiments are also provided to enable a person skilled in the art to make and use the claimed subject matter.

[0007] In a first aspect, an apparatus for treating a tissue site with negative pressure is provided. The apparatus comprises a first polymer film having a plurality of first perforations; a primary manifold adjacent to the first polymer film; and a second polymer film adjacent to the primary manifold and having a plurality of second perforations. The primary manifold comprises a plurality of primary nodes and a plurality of links, the primary nodes and the links being interconnected to define a grid of windows that are transparent. The first polymer film is bonded to the second polymer film at least partially around a periphery of the apparatus and wherein the first polymer film is bonded to the second polymer film in a center window of the primary manifold.

[0008] In a second aspect, a system for treating a tissue site with negative pressure is provided. The system comprises a dressing configured to be placed adjacent to the tissue site and a secondary manifold configured to be positioned adjacent the dressing opposite the tissue site. The system further comprises a drape configured to be positioned over the dressing and the secondary manifold and seal to tissue adjacent to the tissue site to form a sealed space and a negative-pressure source configured to provide negative pressure to the sealed space. The dressing comprises the apparatus according to the first aspect.

[0009] In a third aspect, a method of treating a tissue site with negative pressure is provided. The method comprises applying a dressing to the tissue site; positioning a secondary manifold over the dressing; placing a drape over the dressing and the secondary manifold; and sealing the drape to tissue adjacent to the tissue site to form a sealed space beneath the cover. The method further comprises applying therapeutic levels of negative pressure to the tissue site through the dressing and observing the tissue site through the windows to evaluate a state of the tissue site. The dressing comprises an apparatus according to the first aspect.

[0010] Objectives, advantages, and a preferred mode of making and using the claimed subject matter may be understood best by reference to the accompanying drawings in conjunction with the following detailed description of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a block diagram of an example embodiment of a therapy system that can provide negative-pressure treatment and instillation treatment in accordance with this specification;

[0012] FIG. 2 is an exploded view of an example embodiment of a tissue interface, illustrating additional details that may be associated with some embodiments of the therapy system of FIG. 1; [0013] FIG. 3 is an isometric view of an assembled example of the tissue interface of FIG. 2;

[0014] FIG. 4A is a cross-sectional view of the example tissue interface of FIG. 3 taken at line 4-4; [0015] FIG. 4B is a cross-sectional view of another example tissue interface; [0016] FIG. 5 is an isometric view of an exemplary primary manifold;

[0017] FIG. 6A is an isometric view of another exemplary primary manifold;

[0018] FIG. 6B is an isometric view of a portion of the exemplary primary manifold of FIG. 6 A;

[0019] FIG. 7A is an isometric view and a top view of an exemplary window frame of a primary manifold;

[0020] FIG. 7B is an isometric view and a top view of an additional exemplary window frame of a primary manifold;

[0021] FIG. 7C is an isometric view and a top view of another exemplary window frame of a primary manifold;

[0022] FIG. 7D is an isometric view and a top view of a further exemplary window frame of a primary manifold;

[0023] FIG. 8 is a top view of a portion of an exemplary primary manifold;

[0024] FIGS. 9 A and 9B are bottom views illustrating details that may be associated with some embodiments of the example tissue interface of FIG. 2;

[0025] FIG. 10A is a photograph of an exemplary tissue interface;

[0026] FIG. 10B is a photograph of an exemplary tissue interface wrapped around a tube;

[0027] FIG. 11 is an exploded view of an example embodiment of a dressing including the tissue interface of FIG. 2, illustrating additional details that may be associated with some embodiments of the therapy system of FIG. 1;

[0028] FIG. 12 is an isometric view of an assembled example of the dressing of FIG. 11;

[0029] FIG. 13 is a cross-sectional view of the example dressing of FIG. 12, taken at line 13-13, applied to a tissue site, and illustrating additional details that may be associated with the therapy system of FIG. 1, in accordance with this specification;

[0030] FIG. 14A is a detail view, taken at reference FIG. 14A in FIG. 13, illustrating details that may be associated with some example embodiments of the example dressing of FIG. 13; and

[0031] FIG. 14B illustrates additional details that may be associated with the detail view of FIG. 14A in some embodiments of the dressing of FIG. 13.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0032] The following description of example embodiments provides information that enables a person skilled in the art to make and use the subject matter set forth in the appended claims, but it may omit certain details already well-known in the art. The following detailed description is, therefore, to be taken as illustrative and not limiting.

[0033] FIG. 1 is a block diagram of an example embodiment of a therapy system 100 that can provide negative-pressure therapy with instillation of topical treatment solutions to a tissue site in accordance with this specification.

[0034] The term “tissue site” in this context broadly refers to a wound, defect, or other treatment target located on or within tissue, including, but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. A wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial-thickness bums, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term “tissue site” may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be applied to a tissue site to grow additional tissue that may be harvested and transplanted.

[0035] The therapy system 100 may include a source or supply of negative pressure, such as a negative-pressure source 105, and one or more distribution components. A distribution component is preferably detachable and may be disposable, reusable, or recyclable. A dressing, such as a dressing 110, and a fluid container, such as a container 115, are examples of distribution components that may be associated with some examples of the therapy system 100. As illustrated in the example of FIG. 1, the dressing 110 may comprise or consist essentially of a tissue interface 120, a cover 125, or both in some embodiments.

[0036] A fluid conductor is another illustrative example of a distribution component. A “fluid conductor,” in this context, broadly includes a tube, pipe, hose, conduit, or other structure with one or more lumina or open pathways adapted to convey a fluid between two ends. Typically, a tube is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary. Moreover, some fluid conductors may be molded into or otherwise integrally combined with other components. Distribution components may also include or comprise interfaces or fluid ports to facilitate coupling and de-coupling other components. In some embodiments, for example, a dressing interface or connector may facilitate coupling a fluid conductor to the dressing 110. For example, such a dressing interface may be a SENSAT.R.A.C.™ Pad available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0037] The therapy system 100 may also include a regulator or controller, such as a controller 130. Additionally, the therapy system 100 may include sensors to measure operating parameters and provide feedback signals to the controller 130 indicative of the operating parameters. As illustrated in FIG. 1, for example, the therapy system 100 may include a first sensor 135 and a second sensor 140 coupled to the controller 130.

[0038] The therapy system 100 may also include a source of instillation solution. For example, a solution source 145 may be fluidly coupled to the dressing 110, as illustrated in the example embodiment of FIG. 1. The solution source 145 may be fluidly coupled to a positive-pressure source such as a positive-pressure source 150, a negative-pressure source such as the negative-pressure source 105, or both in some embodiments. A regulator, such as an instillation regulator 155, may also be fluidly coupled to the solution source 145 and the dressing 110 to ensure proper dosage of instillation solution (e.g., saline) to a tissue site. For example, the instillation regulator 155 may comprise a piston that can be pneumatically actuated by the negative-pressure source 105 to draw instillation solution from the solution source during a negative-pressure interval and to instill the solution to a dressing during a venting interval. Additionally or alternatively, the controller 130 may be coupled to the negative-pressure source 105, the positive-pressure source 150, or both, to control dosage of instillation solution to a tissue site. In some embodiments, the instillation regulator 155 may also be fluidly coupled to the negative-pressure source 105 through the dressing 110, as illustrated in the example of FIG. 1.

[0039] Some components of the therapy 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 105 may be combined with the controller 130, the solution source 145, and other components into a therapy unit.

[0040] In general, 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 may be indirectly coupled to the dressing 110 through the container 115. Coupling may include fluid, mechanical, thermal, electrical, or chemical coupling (such as a chemical bond), or some combination of coupling in some contexts. For example, the negative-pressure source 105 may be electrically coupled to the controller 130 and may be fluidly coupled to one or more distribution components to provide a fluid path to a tissue site. In some embodiments, components may also be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material.

[0041] A negative-pressure supply, such as the negative-pressure source 105, may be a reservoir of air at a negative pressure or may be a manual or electrically -powered device, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micro-pump, for example. “Negative pressure” or “reduced pressure” generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to a sealed therapeutic environment. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. Alternatively, the pressure may be less than a hydrostatic pressure associated with tissue at the tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures. References to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure. While the amount and nature of negative pressure provided by the negative-pressure source 105 may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -5 mm Hg (-667 Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are between -50 mm Hg (-6.7 kPa) and -300 mm Hg (-39.9 kPa).

[0042] The container 115 is representative of a container, canister, pouch, or other storage component, which can be used to manage exudates and other fluids withdrawn from a tissue site. In many environments, a rigid container may be preferred or required for collecting, storing, and disposing of fluids. In other environments, fluids may be properly disposed of without rigid container storage, and a re-usable container could reduce waste and costs associated with negative-pressure therapy.

[0043] A controller, such as the controller 130, may be a microprocessor or computer programmed to operate one or more components of the therapy system 100, such as the negative-pressure source 105. In some embodiments, for example, the controller 130 may be a microcontroller, which generally comprises an integrated circuit containing a processor core and a memory programmed to directly or indirectly control one or more operating parameters of the therapy system 100. Operating parameters may include the power applied to the negative-pressure source 105, the pressure generated by the negative-pressure source 105, or the pressure distributed to the tissue interface 120, for example. The controller 130 is also preferably configured to receive one or more input signals, such as a feedback signal, and programmed to modify one or more operating parameters based on the input signals. [0044] Sensors, such as the first sensor 135 and the second sensor 140, are generally known in the art as any apparatus operable to detect or measure a physical phenomenon or property, and generally provide a signal indicative of the phenomenon or property that is detected or measured. For example, the 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 pressure in a pneumatic pathway and convert the measurement to a signal indicative of the pressure measured. In some embodiments, for example, the first sensor 135 may be a piezo-resistive strain gauge. The second sensor 140 may optionally measure operating parameters of the negative-pressure source 105, such as a voltage or current, in some embodiments. Preferably, the signals from the first sensor 135 and the second sensor 140 are suitable as an input signal to the controller 130, but some signal conditioning may be appropriate in some embodiments. For example, the signal may need to be filtered or amplified before it can be processed by the controller 130. Typically, the signal is an electrical signal, but may be represented in other forms, such as an optical signal.

[0045] The tissue interface 120 can be generally adapted to partially or fully contact a tissue site. In some embodiments, the tissue interface 120 may comprise or consist essentially of a manifold. A manifold in this context may comprise or consist essentially of a means for collecting or distributing fluid across the tissue interface 120 under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure across the tissue interface 120, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid, such as fluid from a source of instillation solution, across a tissue site.

[0046] In some embodiments, the cover 125 may provide a bacterial barrier and protection from physical trauma. The cover 125 may also be constmcted from a material that can reduce evaporative losses and provide a fluid seal between two components or two environments, such as between a therapeutic environment and a local external environment. The cover 125 may comprise or consist of, for example, an elastomeric film or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. The cover 125 may be substantially clear or optically transparent. The cover 125 may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least 250 grams per square meter per twenty- four hours in some embodiments, measured using an upright cup technique according to ASTM E96/E96M Upright Cup Method at 38°C and 10% relative humidity (RH). In some embodiments, an MVTR up to 5,000 grams per square meter per twenty -four hours may provide effective breathability and mechanical properties.

[0047] An attachment device may be used to attach the cover 125 to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many forms. For example, an attachment device may be a medically -acceptable, pressure-sensitive adhesive configured to bond the cover 125 to epidermis around a tissue site. In some embodiments, for example, some 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 25-65 grams per square meter (g.s.m.). In illustrative embodiments, the adhesive may be substantially clear or optically transparent. Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.

[0048] In some embodiments, an attachment device may be formed from a soft, pliable material suitable for providing a fluid seal with a tissue site, such as a suitable gel material, and may have a substantially flat surface. The attachment device may include, without limitation, a silicone gel, a soft silicone, hydrocolloid, hydrogel, polyurethane gel, polyolefin gel, hydrogenated styrenic copolymer gel, a foamed gel, a soft closed-cell foam such as polyurethanes and polyolefins coated with an adhesive, polyurethane, polyolefin, or hydrogenated styrenic copolymers. In some embodiments, the attachment device may have a thickness between about 200 micrometers and about 1,000 micrometers. Further, the attachment device may be formed from hydrophobic or hydrophilic materials.

[0049] In some embodiments, the attachment device may be a hydrophobic-coated material. For example, the attachment device may be formed by coating a spaced material, such as, for example, woven, nonwoven, molded, or extruded mesh with a hydrophobic material. The hydrophobic material for the coating may be a soft silicone, for example.

[0050] In some embodiments, the dressing 110 may include a release liner (not shown) to protect the adhesive 1330 prior to use. The release liner may also provide stiffness to assist with, for example, deployment of the dressing 110. The release liner may be, for example, a casting paper, a film, or polyethylene. Further, in some embodiments, the release liner may be a polyester material such as a polyethylene terephthalate (PET), or similar polar semi-crystalline polymer. The use of a polar semicrystalline polymer for the release liner may substantially preclude wrinkling or other deformation of the dressing 110. For example, the polar semi-crystalline polymer may be highly orientated and resistant to softening, swelling, or other deformation that may occur when objects are brought into contact with the layers and/or components of the dressing 110, or when the dressing 110 is subjected to temperature or environmental variations, or during sterilization. Further, a release agent may be disposed on a top surface of the release liner that is configured to contact the bottom surface of the adhesive 1330. For example, the release agent may be a silicone coating and may have a release factor suitable to facilitate removal of the release liner by hand and without damaging or deforming the dressing 110. In some embodiments, the release agent may be a fluorocarbon or a fluorosilicone, for example. In other embodiments, the release liner may be uncoated or otherwise used without a release agent.

[0051] An attachment device may be sufficiently tacky at the bottom surface to hold the dressing 110 in position relative to the epidermis 1315 and wound 1310, while also allowing the dressing 110 to be removed or repositioned without trauma to the epidermis 1315, wound 1310, and/or tissue site 1305. For example, including a silicone polyurethane material, which may form sealing couplings at the bottom surface with the epidermis 2110. In some embodiments, the bond strength or tackiness of the sealing couplings may have a peel adhesion or resistance to being peeled from a stainless-steel material between about 0.5 N/25 mm to about 1.5 N/25 mm on stainless steel substrate at 25° C at 50% relative humidity based on ASTM D3330. The attachment device may achieve this bond strength after a contact time of less than 60 seconds. Tackiness may be considered a bond strength of an adhesive after a very low contact time between the adhesive and a substrate.

[0052] The solution source 145 may also be representative of a container, canister, pouch, bag, or other storage component, which can provide a solution for instillation therapy. Compositions of solutions may vary according to a prescribed therapy, but examples of solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions.

[0053] In operation, the tissue interface 120 may be placed within, over, on, or otherwise proximate to a tissue site. If the tissue site is a wound, for example, the tissue interface 120 may partially or completely fill the wound, or it may be placed over the wound. The cover 125 may be placed over the tissue interface 120 (e.g., either of the first polymer film 205 or the second polymer film 215) and sealed to an attachment surface near a tissue site. For example, a drape (e.g., the cover 125) may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing 110 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source 105 can reduce pressure in the sealed therapeutic environment. [0054] The fluid mechanics of using a negative-pressure source to reduce pressure in another component or location, such as within a sealed therapeutic environment, can be mathematically complex. However, the basic principles of fluid mechanics applicable to negative-pressure therapy and instillation are generally well-known to those skilled in the art, and the process of reducing pressure may be described illustratively herein as “delivering,” “distributing,” or “generating” negative pressure, for example.

[0055] In general, exudate and other fluid flow toward lower pressure along a fluid path. Thus, the term “downstream” typically implies something in a fluid path relatively closer to a source of negative pressure or further away from a source of positive pressure. Conversely, the term “upstream” implies something relatively further away from a source of negative pressure or closer to a source of positive pressure. Similarly, it may be convenient to describe certain features in terms of fluid “inlet” or “outlet” in such a frame of reference. This orientation is generally presumed for purposes of describing various features and components herein. However, the fluid path may also be reversed in some applications, such as by substituting a positive-pressure source for a negative-pressure source, and this descriptive convention should not be construed as a limiting convention.

[0056] Negative pressure applied across the tissue site through the tissue interface 120 in the sealed therapeutic environment can induce macro-strain and micro-strain in the tissue site. Negative pressure can also remove exudate and other fluid from a tissue site, which can be collected in container 115. [0057] 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, controller 130 may include an input for receiving a desired target pressure and may be programmed for processing data relating to the setting and inputting of the target pressure to be applied to the tissue interface 120. In some example embodiments, the target pressure may be a fixed pressure value set by an operator as the target negative pressure desired for therapy at a tissue site and then provided as input to the controller 130. The target pressure may vary from tissue site to tissue site based on the type of tissue forming a tissue site, the type of injury or wound (if any), the medical condition of the patient, and the preference of the attending physician. After selecting a desired target pressure, the controller 130 can 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.

[0058] In some embodiments, the controller 130 may have a continuous pressure mode, in which the negative-pressure source 105 is operated to provide a constant target negative pressure for the duration of treatment or until manually deactivated. Additionally or alternatively, the controller may have an intermittent pressure mode. For example, the controller 130 can operate the negative-pressure source 105 to cycle between a target pressure and atmospheric pressure. For example, the target pressure may be set at a value of 135 mmHg for a specified period of time (e.g., 5 min), followed by a specified period of time (e.g., 2 min) of deactivation. The cycle can be repeated by activating the negative-pressure source 105, which can form a square wave pattern between the target pressure and atmospheric pressure.

[0059] In some example embodiments, the increase in negative-pressure from ambient pressure to the target pressure may not be instantaneous. For example, the negative-pressure source 105 and the dressing 110 may have an initial rise time. The initial rise time may vary depending on the type of dressing and therapy equipment being used. For example, the initial rise time for one therapy system may be in a range of about 20-30 mmHg/second and in a range of about 5-10 mmHg/second for another therapy system. If the therapy system 100 is operating in an intermittent mode, the repeating rise time may be a value substantially equal to the initial rise time.

[0060] In some example dynamic pressure control modes, the target pressure can vary with time. For example, the target pressure may vary in the form of a triangular waveform, varying between a negative pressure of 50 and 135 mmHg with a rise time set at a rate of +25 mmHg/min. and a descent time set at -25 mmHg/min. In other embodiments of the therapy system 100, the triangular waveform may vary between negative pressure of 25 and 135 mmHg with a rise time set at a rate of +30 mmHg/min and a descent time set at -30 mmHg/min.

[0061] In some embodiments, the controller 130 may control or determine a variable target pressure in a dynamic pressure mode, and the variable target pressure may vary between a maximum and minimum pressure value that may be set as an input prescribed by an operator as the range of desired negative pressure. The variable target pressure may also be processed and controlled by the controller 130, which can vary the target pressure according to a predetermined waveform, such as a triangular waveform, a sine waveform, or a saw-tooth waveform. In some embodiments, the waveform may be set by an operator as the predetermined or time-varying negative pressure desired for therapy.

[0062] In some embodiments, the controller 130 may receive and process data, such as data related to instillation solution prescribed by a clinician, the volume of fluid or solution to be instilled to a tissue site (“fill volume”), and the amount of time prescribed for leaving solution at a tissue site (“dwell time”) before applying a negative pressure to the tissue site. The fill volume may be, for example, between 10 and 500 mL, and the dwell time may be between one second to 30 minutes. The controller 130 may also control the operation of one or more components of the therapy system 100 to instill solution. For example, the controller 130 may manage fluid distributed from the solution source 145 to the tissue interface 120. In some embodiments, fluid may be instilled to a tissue site by applying a negative pressure from the negative-pressure source 105 to reduce the pressure at the tissue site, drawing solution into the tissue interface 120. In some embodiments, solution may be instilled to a tissue site by applying a positive pressure from the positive-pressure source 150 to move solution from the solution source 145 to the tissue interface 120. Additionally or alternatively, the solution source 145 may be elevated to a height sufficient to allow gravity to move solution into the tissue interface 120. [0063] The controller 130 may also control the fluid dynamics of instillation by providing a continuous flow of solution or an intermittent flow of solution. Negative pressure may be applied to provide either continuous flow or intermittent flow of solution. The application of negative pressure may be implemented to provide a continuous pressure mode of operation to achieve a continuous flow rate of instillation solution through the tissue interface 120, or it may be implemented to provide a dynamic pressure mode of operation to vary the flow rate of instillation solution through the tissue interface 120. In an intermittent mode, a specific fill volume and dwell time may be provided, depending, for example, on the type of tissue site being treated and the type of dressing being utilized. After or during instillation of solution, negative-pressure treatment may be applied. The controller 130 may be utilized to select a mode of operation and the duration of the negative pressure treatment before commencing another instillation cycle.

[0064] In a first aspect, an apparatus is provided, for treating a tissue site with negative pressure, the apparatus comprising: a first polymer film having a plurality of first perforations; a primary manifold adjacent to the first polymer film, the primary manifold comprising a plurality of primary nodes and a plurality of links, the primary nodes and the links being interconnected to define a grid of windows that are transparent; and a second polymer film adjacent to the primary manifold, the second polymer film having a plurality of second perforations, wherein the first polymer film is bonded to the second polymer film at least partially around a periphery of the apparatus and wherein the first polymer film is bonded to the second polymer film in a center window of the primary manifold.

[0065] In a second aspect, a system for treating a tissue site with negative pressure is provided. The system comprises: a dressing configured to be placed adjacent to the tissue site, the dressing comprising the apparatus according to any embodiment of the first aspect; a secondary manifold configured to be positioned adjacent the dressing opposite the tissue site; a drape configured to be positioned over the dressing and the secondary manifold and seal to tissue adjacent to the tissue site to form a sealed space; and a negative-pressure source configured to provide negative pressure to the sealed space. [0066] In a third aspect, a method of treating a tissue site with negative pressure is provided. The method comprises: applying a dressing to the tissue site, the dressing comprising an apparatus according to any embodiment of the first aspect; positioning a secondary manifold over the dressing; placing a drape over the dressing and the secondary manifold; sealing the drape to tissue adjacent to the tissue site to form a sealed space beneath the cover; applying therapeutic levels of negative pressure to the tissue site through the dressing; and observing the tissue site through the windows to evaluate a state of the tissue site. [0067] The various features of the first through third aspects are described in detail throughout this disclosure.

[0068] FIG. 2 is an exploded view of an example of the tissue interface 120 (e.g., an apparatus of the first aspect) of FIG. 1, illustrating additional details associated with the tissue interface 120 comprising more than one layer. In the example of FIG. 2, the tissue interface 120 comprises a first polymer film 205, a primary manifold 210, and a second polymer film 215. In some embodiments, the first polymer film 205 may be disposed adjacent to the primary manifold 210, and the second polymer film 215 may be disposed adjacent to the primary manifold 210 opposite the first polymer film 205. For example, the first polymer film 205 and the primary manifold 210 may be stacked so that the first polymer film 205 is in contact with the primary manifold 210. The second polymer film 215 and the primary manifold 210 may be stacked so that the second polymer film 215 is in contact with the primary manifold 210.

[0069] The first polymer film 205 may include a suitable structure for controlling or managing fluid flow. In some embodiments, the first polymer film 205 may be a fluid-control layer which may include a liquid-impermeable, vapor permeable elastomeric material. In example embodiments, the first polymer film 205 may include a polymer film. For example, the first polymer film 205 may include a polyolefin film, such as a polyethylene film. In illustrative embodiments, the first polymer film 205 may be substantially clear or optically transparent. In some embodiments, the first polymer film 205 may include the same material as the cover 125. In example embodiments, the first polymer film 205 may include a biocompatible polyurethane film tested and certified according to the USP Class VI Standard. The first polymer film 205 may also have a smooth or matte surface texture in some embodiments. A glossy or shiny finish better or equal to a grade B3 according to the SPI (Society of Plastics Industry) standards may be particularly advantageous for some applications. In some embodiments, variations in surface height may be limited to acceptable tolerances. For example, the surface of the first polymer film 205 may be a substantially flat surface, with height variations limited to 0.2 millimeters over a centimeter.

[0070] In some embodiments, the first polymer film 205 may be hydrophobic. The hydrophobicity of the first polymer film 205 may vary, but may have a contact angle with water of at least ninety degrees in some embodiments. In some embodiments, the first polymer film 205 may have a contact angle with water of no more than 150 degrees. For example, in some embodiments, the contact angle of the first polymer film 205 may be in a range of at least 90 degrees to about 120 degrees, or in a range of at least 120 degrees to 150 degrees. Water contact angles may be measured used any standard apparatus. Although manual goniometers can be used to visually approximate contact angles, contact angle measuring instruments can often include an integrated system involving a level stage, a liquid dropper such as a syringe, a camera, and software designed to calculate contact angles more accurately and precisely, among other things. Non-limiting examples of such integrated systems may include the FTA125, FTA200, FTA2000, and FTA4000 systems, all commercially available from First Ten Angstroms, Inc., of Portsmouth, VA, and the DTA25, DTA30, and DTA100 systems, all commercially available from Kruss GmbH of Hamburg, Germany. Unless otherwise specified, water contact angles herein are measured using deionized and distilled water on a level sample surface for a sessile drop added from a height of no more than 5 cm in air at 20-25° C and 20-50% relative humidity. Contact angles herein represent averages of 5-9 measured values, discarding both the highest and the lowest measured values. The hydrophobicity of the first polymer film 205 may be further enhanced with a hydrophobic coating of other materials, such as silicones and fluorocarbons. [0071] The first polymer film 205 may also be suitable for welding to other layers, including the primary manifold 210 and the second polymer film 215. For example, the first polymer film 205 may be adapted for welding to polymers such as polyurethane, polyurethane films, and polyurethane foams using heat, radio-frequency (RF) welding, or other methods such as ultrasonic welding. RF welding may be particularly suitable for more polar materials, such as polyurethane, polyamides, polyesters, and acrylates. Sacrificial polar interfaces may be used to facilitate RF welding of less polar film materials, such as polyethylene.

[0072] The area density of the first polymer film 205 may vary according to a prescribed therapy or application. In some embodiments, an area density of less than 40 grams per square meter may be suitable, and an area density of about 20-30 grams per square meter may be particularly advantageous for some applications.

[0073] In some embodiments, for example, the first polymer film 205 may include a hydrophobic polymer, such as a polyethylene film. The simple and inert structure of polyethylene can provide a surface that interacts little, if any, with biological tissues and fluids, providing a surface that may encourage the free flow of liquids and low adherence, which can be particularly advantageous for many applications. Other suitable polymeric films include polyurethanes, acrylics, polyolefin (such as cyclic olefin copolymers), polyacetates, polyamides, polyesters, copolyesters, PEBAX block copolymers, thermoplastic elastomers, thermoplastic vulcanizates, polyethers, polyvinyl alcohols, polypropylene, polymethylpentene, polycarbonate, styreneics, silicones, fluoropolymers, and acetates. A thickness between about 20 micrometers and about 500 micrometers may be suitable for many applications. For example, thicknesses of 23 micrometers, 25 micrometers, 100 micrometers, 250 micrometers, 300 micrometers, and 500 micrometers may be suitable for particular applications. More polar films suitable for laminating to a polyethylene film include polyamide, co-poly esters, ionomers, and acrylics. To aid in the bond between a polyethylene and polar film, tie layers may be used, such as ethylene vinyl acetate, or modified polyurethanes. An ethyl methyl acrylate (EMA) film may also have suitable hydrophobic and welding properties for some configurations.

[0074] As illustrated in the example of FIG. 2, the first polymer film 205 may have one or more fluid passages 220, which can be distributed uniformly or randomly across the first polymer film 205. The fluid passages 220 may be bi-directional and pressure-responsive. For example, each of the fluid passages 220 generally may be an elastic passage that is normally unstrained to substantially reduce liquid flow, and can expand or open in response to a pressure gradient. In some embodiments, the fluid passages 220 include perforations in the first polymer film 205. Perforations may be formed by removing material from the first polymer film 205. For example, perforations may be formed by cutting through the first polymer film 205, which may also deform the edges of the perforations in some embodiments. In the absence of a pressure gradient across the perforations, the passages may be sufficiently small to form a seal or fluid restriction, which can substantially reduce or prevent liquid flow. Additionally or alternatively, one or more of the passages may be an elastomeric valve that is normally closed when unstrained to substantially prevent liquid flow, and can open in response to a pressure gradient. A fenestration in the first polymer film 205 may be a suitable valve for some applications. Fenestrations may also be formed by removing material from the first polymer film, but the amount of material removed and the resulting dimensions of the fenestrations may be up to an order of magnitude less than perforations, and may not deform the edges.

[0075] For example, some embodiments of the fluid passages 220 may include one or more slits, slots or combinations of slits and slots in the first polymer film 205. In some examples, the fluid passages 220 may include linear slots having a length less than 5 millimeters and a width less than 2 millimeter. The length may be at least 2 millimeters, and the width may be at least 0.5 millimeters in some embodiments. A length in a range of about 2 millimeters to about 5 millimeters and a width in a range of about 0.5 millimeters to about 2 millimeters may be particularly suitable for many applications, and a tolerance of about 0.1 millimeters may also be acceptable. For example, a length of 3 mm may be suitable. Such dimensions and tolerances may be achieved with a laser cutter, for example. Slots of such configurations may function as imperfect valves that substantially reduce liquid flow in a normally closed or resting state. For example, such slots may form a flow restriction without being completely closed or sealed. The slots can expand or open wider in response to a pressure gradient to allow increased liquid flow. In illustrative embodiments, the fluid passages 220 may comprise or consist of linear slits having a length of less than 5 millimeters. For example, the length may be at least 2 millimeters. A length in a range of about 2 millimeters to about 5 millimeters may be particularly suitable for many applications, and a tolerance of about 0.1 millimeters may also be acceptable. For example, a length of 3 mm may be suitable. In some embodiments, the first polymer film 205 may comprise a top surface 225 opposite a bottom surface 230. The first polymer film 205 may additionally comprise a periphery 235 at an outer perimeter of the first polymer film 205. In illustrative embodiments, the fluid passages 220 may be circular, or any other suitable shape. [0076] In some examples, the primary manifold 210 may be or may include a flexible grid structure. The flexible grid structure may be formed of or include a variety of polymeric materials. Some examples of the primary manifold 210 may include a plurality of sections without polymer, which form a plurality of windows 240. The windows 240 may be formed through the primary manifold 210, allowing the user to see through the primary manifold 210. In illustrative embodiments, the windows 240 may be defined as regions of the primary manifold 210 without material. As such, the windows 240 are preferably open apertures. For example, the windows 240 may also form flow channels, facilitating fluid flow through the primary manifold 210. In illustrative embodiments, the primary manifold 210 comprises a molded or cast polymer, including polymeric materials with a hardness in a range of about Shore 10A to about Shore 40A. For example, the primary manifold 210 may be formed from a polyurethane or silicone-based material with a hardness in a range of Shore 20A to Shore 40 A. A polymer with a hardness of Shore 10A may be suitable for particular applications. Some suitable polymers within this Shore range include polyurethane and silicone-based materials. According to illustrative embodiments, the windows 240 may have a polygonal or circular frame. For example, the windows 240 may have a cross-shaped frame or a quatrefoil-shaped frame. In example embodiments, the frames for the windows 240 may be formed from regular shapes such as triangles, squares, pentagons, hexagons, or any other regular shape. In some embodiments, the frames for windows 240 may be formed from irregular shapes. According to example embodiments, the windows 240 may have a width of at least 8 millimeters, such as in a range of about 8 millimeters to about 15 millimeters.

[0077] As illustrated in the example of FIG. 2, the primary manifold 210 may be formed from a single, substantially uniform material. In certain embodiments, the primary manifold is free of a porous foam. The primary manifold 210 may comprise a plurality of primary nodes 245 arranged in a grid pattern. For example, the plurality of primary nodes 245 may be arranged in a pattern of rows and columns. Each primary node 245 within a row may be connected to at least one adjacent primary node 245 by a link 250. The centroid of each primary node 245 within a row may be aligned with a long axis of each link 250 connecting the primary nodes 245 within a row. In example embodiments, each primary node 245 within a column may be connected or linked to at least one adjacent primary node 245 by link 250. The centroid of each primary node 245 within a column may be aligned with a long axis of each link 250 connecting the primary nodes 245 within a row. In example embodiments, the links 250 within each row may be parallel with the links 250 within each other row. In example embodiments, the links 250 within each column may be parallel with the links 250 within each other column. For example, the links 250 within each column may be substantially orthogonal to the links 250 within each row. As illustrated by the example of FIG. 2, the top surfaces of the primary nodes 245 and the top surfaces of the links 250 may be substantially coplanar with a top surface 255 of the primary manifold 210. In some embodiments, the bottom surfaces of the primary nodes 245 and the bottom surfaces of the links 250 may be substantially coplanar with a bottom surface 260 of the primary manifold 210. In example embodiments, the plane formed by the top surface 255 of the primary manifold 210 may be substantially parallel with the plane formed by the bottom surface 260 of the primary manifold 210. The primary manifold 210 may additionally comprise a periphery 265 formed at an outer perimeter of primary manifold 210.

[0078] According to example embodiments, the primary nodes 245 may have a substantially circular profile in the plane formed by the top surface 255 of the primary manifold 210 (e.g., may be spherical in three dimensions. For example, the circular profiles of the primary nodes 245 may have a diameter in a range of about 4 mm to about 12 mm. In example embodiments, the links 250 may have a substantially rectangular profile in the plane formed by the top surface 255 of the primary manifold 210. For example, the substantially rectangular profiles of the links 250 may have a length in a range of about 8 mm to about 15 mm.

[0079] In some embodiments, the primary nodes 245 may be arranged in a hexagonal or circular pattern, or any suitable pattern. In illustrative embodiments, the primary nodes may be any suitable three-dimensional shape. In some embodiments, the windows 240 may be framed by triangles, squares, rectangles, crosses, polygons, quatrefoils, or any other suitable shapes.

[0080] As illustrated by the example of FIG. 2, the second polymer film 215 may comprise or consist essentially of a means for controlling or managing fluid flow. In some embodiments, the second polymer film 215 may be a fluid-control layer comprising or consisting essentially of a liquid- impermeable, vapor permeable elastomeric material. In example embodiments, the second polymer film 215 may comprise or consist essentially of a polymer film. For example, the second polymer film 215 may comprise or consist essentially of a polyolefin film, such as a polyethylene film. In some embodiments, the second polymer film 215 may comprise or consist essentially of the same material as the first polymer film 205. The second polymer film 215 may also have a smooth or matte surface texture in some embodiments. A glossy or shiny finish better or equal to a grade B3 according to the SPI (Society of Plastics Industry) standards may be particularly advantageous for some applications. In some embodiments, variations in surface height may be limited to acceptable tolerances. For example, the surface of the second polymer film 215 may be a substantially flat surface, with height variations limited to 0.2 millimeters over a centimeter. In example embodiments, the second polymer film 215 may be hydrophobic. For example, the second polymer film 215 may have a contact angle with water of no more than 150 degrees. For example, the contact angle of the second polymer film 215 may have a contact angle in a range of at least 90 degrees to about 120 degrees, or in a range of at least 120 degrees to 150 degrees.

[0081] The second polymer film 215 may also be suitable for welding to other layers, including the first polymer film 205 and the primary manifold 210. For example, the second polymer film 215 may be adapted for welding to polymers such as polyurethanes using heat, radio-frequency (RF) welding, or other methods such as ultrasonic welding. For instance, the first polymer film 205 and the second polymer film 215 may be welded to each other in at least one of the windows of the primary manifold 210, e.g., spot welded. RF welding may be particularly suitable for more polar materials, such as polyurethane, polyamides, polyesters, and acrylates. Sacrificial polar interfaces may be used to facilitate RF welding of less polar film materials, such as polyethylene. The area density of the second polymer film 215 may vary according to a prescribed therapy or application. In some embodiments, an area density of less than 40 grams per square meter may be suitable, and an area density of about 20-30 grams per square meter may be particularly advantageous for some applications. In some embodiments, for example, the second polymer fdm 215 may comprise or consist essentially of a hydrophobic polymer, such as a polyethylene film. Other suitable polymers include the polymeric films described previously with respect to the first polymer fdm 205. A thickness between about 10 micrometers and about 500 micrometers may be suitable for many applications. For example, a thickness of 23 micrometers may be suitable for particular applications. In illustrative embodiments, a thickness of 15 to 25 micrometers may be suitable for particular applications. In some embodiments, the thickness of the second polymer film 215 may be less than the thickness of the first polymer film 205. In some embodiments, the thickness of the second polymer film 215 may be the same as the thickness of the first polymer film 205. The second polymer fdm 215 may be substantially clear, or optically transparent. As illustrated in the example of FIG. 2, the second polymer film 215 may have one or more fluid passages 270. Fluid passages 270 may be substantially similar to or the same as the fluid passages 220 described previously with respect to the first polymer film 205. In some embodiments, the second polymer film 215 may comprise a top surface 275 opposite a bottom surface 280. The second polymer film 215 may additionally comprise a periphery 285 at an outer perimeter of the second polymer film 215.

[0082] FIG. 3 shows an isometric view of some embodiments of the tissue interface 120 with the first polymer film 205, the primary manifold 210, and the second polymer film 215 in assembled form. In illustrative embodiments, the periphery 235 of the first polymer film 205 may be substantially coextensive with the periphery 285 of the second polymer film 215. In some embodiments, a portion of the first polymer film 205 near the periphery 235 of the first polymer film 205 may be coupled, bonded, welded, or adhered to a portion of the second polymer film 215 near the periphery 285 of the second polymer film 215 at a border region 305 to define an interior space 310 of the tissue interface 120. Coupling may also include mechanical, thermal, or chemical coupling (such as a chemical bond) in some contexts. The primary manifold 210 may be positioned within the interior space of the tissue interface 120. In some cases, the primary manifold 210 is bonded to at least one of the first polymer film 205 or the second polymer film 215. Optionally, the first polymer film 205 is bonded to the second polymer film 215 all the way around the periphery 285 of the apparatus (e.g., at a border region 305). [0083] FIG. 4A shows a cross-sectional view of the example tissue interface 120 of FIG. 3 taken at line 4-4. Assembled, the top surface 225 of the first polymer film 205 may be adjacent to the bottom surface 260 of the primary manifold 210. The top surface 255 of the primary manifold 210 may be adjacent to the bottom surface 280 of the second polymer film 215. The portion of the first polymer film 205 coupled, bonded, welded, or adhered to the portion of the second polymer film 215 may form the border region 305 of the tissue interface 120. For instance, the first polymer film 205 is bonded to the second polymer film 215 at least partially around a periphery of the apparatus (e.g., tissue interface 120) and the first polymer film 205 is bonded 207 to the second polymer film 215 in a center window 240 of the primary manifold 210 to minimize the primary manifold 210 from moving relative to the first polymer film 205 and/or the second polymer film 215. For instance, when the first 205 and second polymer films 215 are bonded at least partially around their peripheries, they generally form a “container” inside which the primary manifold 210 is disposed, and it has been discovered that lacking any bond of the first polymer film 205 to the second polymer film 215 through a window 240 tends to allow the primary manifold 210 to move freely within the container, which can be undesirable when using the tissue interface 120. Similar to FIG. 4A, FIG. 4B shows a cross- sectional view of an example tissue interface 120 in which the first polymer film 205 and the second polymer film 217 are bonded together 207 in a plurality of the windows 240 of the primary manifold 210. Providing more than one bond 207 may advantageously more effectively secure the primary manifold 210 in place within the tissue interface 120 than a bond 207 solely in a center window 240 of the primary manifold 210.

[0084] In illustrative embodiments, the primary manifold 210 may be positioned within the interior space 310 of the tissue interface 120. For example, the periphery 265 of the primary manifold 210 may be contained within the border region 305 and within the interior space 310. For example, the primary manifold 210 may be contained by the top surface 225 of the first polymer film 205, the bottom surface 280 of the second polymer film 215, and the border region 305. In assembled form, the user is able to see through the tissue interface 120 in a direction approximately normal to the plane formed by the top surface 275 of the second polymer film 215 or the bottom surface 230 of the first polymer film 205. For example, the user may see through the substantially clear or optically transparent first polymer film 205, into and through the windows 240 of the primary manifold 210, and through the substantially clear or optically transparent second polymer film 215.

[0085] Referring now to FIG. 5, an isometric view is provided of one exemplary primary manifold 210. The primary manifold 210 depicted here comprises a plurality of primary nodes 245 and a plurality of links 250, the primary nodes 245 and the links 250 being interconnected to define a grid of windows 240 that are transparent. In this primary manifold 210, there is no shape change between the primary nodes 245 and the links 250; rather, the overall shape of the primary manifold 210 is of a regular grid with fully square frames for each window 240. [0086] Referring to FIGS. 6A and 6B, isometric views are provided of an additional exemplary primary manifold 210. The primary manifold 210 depicted here comprises a plurality of primary nodes 245, a plurality of links 250, and a plurality of secondary nodes 247. The primary nodes 245 and the links 250 are interconnected to define a grid of windows 240 that are transparent, and the secondary nodes 247 are located on the links 250. For example, each primary node 245 may be connected to at least one other primary node 245 by a link 250. In example embodiments, each link 250 may be substantially parallel with or substantially orthogonal to each other link 250 in a plane. For example, each link 250 connected to any one primary node 245 may be orthogonal to an adjacent link 250 connected to the same primary node 245. In example embodiments, each primary node 245 may be spaced a distance d₇ on-center in a first direction from an adjacent primary node 245. Each primary node 245 may be spaced a distance d₈ on-center from an adjacent primary node 245 in a second direction. In illustrative embodiments, the first direction may be orthogonal to the second direction in the same plane. In some embodiments, each primary node 245 may have a diameter wj. In example embodiments, each link 250 may have a width wj. In some embodiments, the primary manifold 210 may have an overall length Li and an overall width Wi. For example, according to some embodiments, d₇ may be about 13 mm, d₈ may be about 13 mm, wi may be about 4 mm, w₂ may be about 1 mm, w₃ may be about 2 mm, Li may be about 182 mm, and Wi may be about 117 mm. According to illustrative embodiments, the primary manifold 210 may include a plurality of windows 240 defined by the negative spaces or portions where there is not material when the primary manifold 210 is viewed from the top. In this primary manifold 210, each of the primary nodes 245 has a spherical shape and each of the secondary nodes 247 has a spherical shape, where the primary nodes 245 have a larger diameter than the secondary nodes 247. The links 250 have a tubular shape. The larger diameter of the primary nodes 245 provide a standoff, e.g., greater a space between the first polymer film 205 and the second polymer film 215 than provided by the secondary nodes 247 or the links 250. For example, as depicted in the exemplary portion shown in FIG. 6B, in some embodiments, the primary nodes 245 may have a diameter twice as large (e.g., 4 millimeters) as the secondary nodes 247 (e.g., 2 millimeters). The actual diameters may be different than what is shown in this figure.

[0087] In some embodiments, each component of the primary manifold 210, such as each primary node 245, each link 250, and each (optional) secondary node 247 may include the same material. For example, the primary manifold 210 may be formed from a molded or cast polymer material, such as a polyurethane or silicone-based material having a hardness between about Shore 20A and about Shore 40 A. For example, a silicone material with a hardness of about Shore 10A may be suitable for particular applications. In example embodiments, the primary manifold 210 may have an overall height Hi. For example, Hi may be about 4 mm.

[0088] Referring to FIGS. 7A-7D, various exemplary frames of windows 240 are shown that may be suitable for certain embodiments of the primary manifold 210. Each includes a plurality of primary nodes 245, links 250, and a window 240 defined by the interconnection of the primary nodes 245 and links 250. The frames of FIGS. 7A-7C are generally squares (although the primary nodes 245 impinge into the square shape, as do the secondary nodes 247 in FIG. 7B), and the frame of FIG. 7D is generally a rectangle. The primary nodes 245 in each of FIGS. 7A, 7B, and 7D have a cylindrical shape, whereas the primary nodes 245 in FIG. 7C have a cubic shape. Each of the primary nodes 245 in the frames of FIGS. 7A-7D is larger in both height and width than the links 250 of each respective frame. As such, in some embodiments, each of the primary nodes comprises a standoff.

[0089] FIG. 8 is a top view of a portion of an exemplary primary manifold that includes a grid of windows 240 that comprises a plurality of different shapes of windows 240. For instance, the primary nodes 245 and links 250 within one primary manifold 210 may be arranged to form triangles 251, squares 252, rectangles 253, trapezoids 254, etc. Again, the shapes are not perfectly triangular, square, rectangular, trapezoidal, etc., in the cases where the primary nodes 245 are larger than the links 250, such as depicted in FIG. 8. This is because the primary nodes 245 extend into the comers of the windows 240. Often, the windows of a primary manifold will have at least one of a polygonal or circular frame.

[0090] Referring again to each of FIGS. 5-8, in some cases, the primary manifold has a first major side 257 that is symmetrical to an opposing second major side 258 (with the reference numbers included in just FIGS. 5 and 6). Advantageously, employing a primary manifold 210 that has symmetrical major surfaces may simplify the use of the tissue interface 120 as it is not required to select a specific side of the tissue interface to place in contact with tissue when both sides are identical. In such cases, it may also be particularly useful for the first polymer fdm 205 and the second polymer film 215 to be the same (e.g., same material, same thickness, etc.).

[0091] Referring again to FIGS. 4A and 4B, in illustrative embodiments, fluid may be transported through the fluid passages 220 of the first polymer film 205 and into the windows 240 of the primary manifold 210, and from the windows 240 through the fluid passages 270 of the second polymer film 215. In example embodiments, fluid may be transported through the fluid passages 270 of the second polymer film 215 and into the windows 240 of the primary manifold 210, and from the windows 240 through the fluid passages 220 of the first polymer film 205. In some embodiments, fluid may be transported through the tissue interface 120. In example embodiments where the primary manifold 210 includes a porous material, fluid may be transported through the flow channels formed within the porous material of the primary manifold 210. In illustrative embodiments, the primary manifold 210 may be sufficiently stiff to resist substantial deformation when a first force 405 and a second force 410 is applied to the manifold. For example, the first force 405 may be substantially normal to the top surface 255 of the primary manifold 210, and the second force 410 may be substantially normal to the bottom surface 260 of the primary manifold 210. In example embodiments, the first force 405 and the second force 410 may be substantially opposite vectors. By preventing the primary manifold 210 from deforming in response to the first force 405 and/or the second force 410, the primary manifold 210 may keep the windows 240 substantially open in response to the applied forces 405 and/or 410. [0092] FIG. 9A is a bottom view illustrating details that may be associated with some embodiments of the example tissue interface 120 of FIG. 2. For example, FIG. 9A illustrates additional details that may be associated with some embodiments of the first polymer film 205. As illustrated in the example of FIG. 9 A, the fluid passages 220 may each consist essentially of one or more slits having a length h. A length of about 3 millimeters may be particularly suitable for some embodiments. FIG. 9 A additionally illustrates an example of a uniform distribution pattern of the fluid passages 220. In FIG. 9 A, the fluid passages 220 are substantially coextensive with the first polymer film 205, and are distributed across the first polymer film 205 in a grid of parallel rows and columns, in which the slits are also mutually parallel to each other. In some embodiments, the rows may be spaced a distance di. A distance of about 3 millimeters on center may be suitable for some embodiments. The fluid passages 220 within each of the rows may be spaced a distance d₂, which may be about 3 millimeters on center in some examples. The fluid passages 220 in adjacent rows may be aligned or offset in some embodiments. For example, adjacent rows may be offset, as illustrated in FIG. 9A, so that the fluid passages 220 are aligned in alternating rows and separated by a distance d₃, which may be about 6 millimeters in some embodiments. The spacing of the fluid passages 220 may vary in some embodiments to increase the density of the fluid passages 220 according to therapeutic requirements. In some embodiments, a plurality of fluid passages 220 may align with the windows 240 of the primary manifold 210 when the tissue interface 120 is assembled. For example, a majority of fluid passages 220 may be aligned with the windows 240 of the primary manifold 210 to facilitate improved moisture transfer through the tissue interface 120 and to facilitate improved manifolding through the tissue interface 120. In illustrative embodiments, a majority of the fluid passages 220 may be aligned with the plurality of primary nodes 245 to improve manifolding around the primary nodes 245 by fluid passages 220 which route over the arc of the primary nodes 245.

[0093] In illustrative embodiments, increasing the thickness of the first polymer film 205 may reduce the stress placed on the wound 1310 by the primary nodes 245 or standoffs 905 when the system 100 is under negative pressure. For example, when therapeutic levels of negative pressure are introduced to the sealed therapeutic environment 1335, the pressure within the sealed therapeutic environment 1335 under the bottom surface 1130 of the cover 125 may be lower than the ambient atmospheric pressure outside of the dressing 110, such as adjacent the top surface 1125 of the cover 125. The resultant force from the pressure gradient draws the cover 125 towards the wound 1310, which also draws the primary manifold 210 towards the wound 1310. As a result, the primary nodes 245 or standoffs 905 may be drawn towards the wound 1310. In examples with a thicker first polymer film 205, a greater portion of the stress field created by the primary node 245 being drawn towards the wound 1310 may be contained within the first polymer film 205, and not transmitted to the wound 1310. The thickness of the first polymer film 205 and the dimensions of the slots or slits forming the fluid passages 220 may be selected to selectively introduce a greater or smaller stress field to the wound 1310. For example, wider slots may be selected for the fluid passages 220 with a thicker first polymer film 205 in order to prevent narrower slots or slits from remaining closed under the application of negative pressure. For example, slits may be suitable as fluid passages 220 in some applications where the first polymer film 205 or second polymer film 215 comprises a thickness of less than about 100 micrometers, and slots may be suitable as fluid passages 220 in some applications where the first polymer film 205 or second polymer film 215 comprises a thickness of greater than about 100 micrometers.

[0094] FIG. 9B is a bottom view illustrating details that may be associated with some embodiments of the example tissue interface 120 of FIG. 2. For example, FIG. 9B illustrates additional details that may be associated with some embodiments of the second polymer film 215. As illustrated in the example of FIG. 9B, the fluid passages 270 may each consist essentially of one or more slits having a length l₂. A length of about 3 millimeters may be particularly suitable for some embodiments. FIG. 9B additionally illustrates an example of a uniform distribution pattern of the fluid passages 270. In FIG. 9B, the fluid passages 270 are substantially coextensive with the second polymer film 215, and are distributed across the second polymer film 215 in a grid of parallel rows and columns, in which the slits are also mutually parallel to each other. In some embodiments, the rows may be spaced a distance d4. A distance of about 3 millimeters on center may be suitable for some embodiments. The fluid passages 270 within each of the rows may be spaced a distance d₅, which may be about 3 millimeters on center in some examples. The fluid passages 270 in adjacent rows may be aligned or offset in some embodiments. For example, adjacent rows may be offset, as illustrated in FIG. 9B, so that the fluid passages 270 are aligned in alternating rows and separated by a distance d₆, which may be about 6 millimeters in some embodiments. The spacing of the fluid passages 270 may vary in some embodiments to increase the density of the fluid passages 270 according to therapeutic requirements. In some embodiments, a plurality of fluid passages 270 may align with the windows 240 of the primary manifold 210 when the tissue interface 120 is assembled. For example, a majority of fluid passages 270 may be aligned with the windows 240 of the primary manifold 210 to facilitate improved moisture transfer through the tissue interface 120 and to facilitate improved manifolding through the tissue interface 120.

[0095] Referring to FIG. 10A, a photograph is provided of an exemplary tissue interface 120, comprising a primary manifold 210 disposed between two polymeric films (e.g., the first polymeric film 205 is shown in the photo). Such a tissue interface 120 may be sufficiently flexible to wrap around a cylinder 1000 without breaking, as shown in the photograph of FIG. 10B. This is advantageous when employing a tissue interface 120 with a wound area that has a variable, especially curved, surface to which the tissue interface 120 should conform upon the application of negative pressure. [0096] FIG. 11 is an exploded view of an example embodiment of a dressing 110 including the tissue interface 120 of FIG. 2, illustrating additional details that may be associated with some embodiments of the therapy system 100 of FIG. 1. In example embodiments, the dressing 110 may include the cover 125 and a secondary manifold 1105. In illustrative embodiments, the cover 125 may be substantially clear or optically transparent. In some embodiments, the secondary manifold 1105 generally comprises or consists essentially of a manifold or a manifold layer, which provides a means for collecting or distributing fluid across the dressing 110 under pressure. In some illustrative embodiments, the pathways of the secondary manifold 1105 may be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, the secondary manifold 1105 may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous material that comprise or can be adapted to form fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam, porous tissue collections, and other porous materials such as gauze or felted mat that generally includes pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, the secondary manifold 1105 may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, the secondary manifold 1105 may be molded to provide surface projections that define interconnected fluid pathways.

[0097] In some embodiments, the secondary manifold 1105 may comprise or consist essentially of a reticulated foam having pore sizes and free volume that may vary according to needs of a prescribed therapy. For example, a reticulated foam having a free volume of at least 90% may be suitable for many therapy applications, and a foam having an average pore size in a range of 400-600 microns may be particularly suitable for some types of therapy. The tensile strength of the secondary manifold 1105 may also vary according to needs of a prescribed therapy. For example, the tensile strength of a foam may be increased for instillation of topical treatment solutions. The 25% compression load deflection of the secondary manifold 1105 may be at least 0.35 pounds per square inch, and the 65% compression load deflection may be at least 0.43 pounds per square inch. In some embodiments, the tensile strength of the secondary manifold 1105 may be at least 10 pounds per square inch. The secondary manifold 1105 may have a tear strength of at least 2.5 pounds per inch. In some embodiments, the secondary manifold 1105 may be a foam comprised of polyols such as polyester or polyether, isocyanate such as toluene diisocyanate, and polymerization modifiers such as amines and tin compounds. In some examples, the secondary manifold 1105 may be a reticulated polyurethane foam such as used in GRANUFOAM™ dressing or V.A.C. VERAFLO™ dressing, both available from KCI of San Antonio, Texas.

[0098] Other suitable materials for the secondary manifold 1105 may include non-woven fabrics (Libeltex, Freudenberg), three-dimensional (3D) polymeric structures (molded polymers, embossed and formed films, and fusion bonded films [Supracor]), and mesh, for example. [0099] In some examples, the secondary manifold 1105 may include a 3D textile, such as various textiles commercially available from Baltex, Muller, and Heathcoates. A 3D textile of polyester fibers may be particularly advantageous for some embodiments. For example, the secondary manifold 1105 may comprise or consist essentially of a three-dimensional weave of polyester fibers. In some embodiments, the fibers may be elastic in at least two dimensions. A puncture-resistant fabric of polyester and cotton fibers having a weight of about 650 grams per square meter and a thickness of about 1-2 millimeters may be particularly advantageous for some embodiments. Such a punctureresistant fabric may have a warp tensile strength of about 330-340 kilograms and a weft tensile strength of about 270-280 kilograms in some embodiments. Another particularly suitable material may be a polyester spacer fabric having a weight of about 470 grams per square meter, which may have a thickness of about 4-5 millimeters in some embodiments. Such a spacer fabric may have a compression strength of about 20-25 kilopascals (at 40% compression). Additionally or alternatively, the secondary manifold 1105 may comprise or consist of a material having substantial linear stretch properties, such as a polyester spacer fabric having 2-way stretch and a weight of about 380 grams per square meter. A suitable spacer fabric may have a thickness of about 3-4 millimeters, and may have a warp and weft tensile strength of about 30-40 kilograms in some embodiments. The fabric may have a close-woven layer of polyester on one or more opposing faces in some examples.

[00100] The secondary manifold 1105 generally has a first planar surface, such as a top surface 1110 opposite a second planar surface, such as a bottom surface 1115. The thickness of the secondary manifold 1105 between the top surface 1110 and the bottom surface 1115 may also vary according to the needs of a prescribed therapy. For example, the thickness of the secondary manifold 1105 may be decreased to relieve stress on other layers. The secondary manifold 1105 also comprises a periphery 1120 around an outer perimeter of the secondary manifold 1105. In some embodiments, a suitable foam secondary manifold 1105 may have a thickness in a range of about 5 millimeters to about 10 millimeters. In example embodiments, a fabric secondary manifold 1105, including 3D textiles and spacer fabrics, may have a thickness in a range of about 2 millimeters to about 8 millimeters.

[00101] The cover 125 generally has a first planar surface, such as a top surface 1125 opposite a bottom surface 1130. In example embodiments, at least a portion of the bottom surface 1130 of the cover 125 may be coated with an adhesive, such as an acrylic adhesive. The cover 125 may also comprise a periphery 1135 around an outer perimeter of the cover 125. An aperture 1140 may be formed in the cover 125. In some embodiments, the periphery 1135 of the cover 125 may be greater than the periphery 1120 of the secondary manifold 1105, the periphery 285 of the second polymer film 215, the periphery 265 of the primary manifold 210, and the periphery 235 of the first polymer film 205. For example, the periphery 1120 of the secondary manifold 1105, the periphery 285 of the second polymer film 215, the periphery 265 of the primary manifold 210, and the periphery 235 of the first polymer film 205 may be contained within the periphery 1135 of the cover 125. In example embodiments, the periphery 1120 of the secondary manifold 1105 may be contained within the periphery 1135 of the cover 125 and the periphery 285 of the second polymer film 215.

[00102] FIG. 11 also illustrates one example of a fluid conductor 1145 and a dressing interface 1150. As shown in the example of FIG. 11, the fluid conductor 1145 may be a flexible tube, which can be fluidly coupled on one end to the dressing interface 1150. The dressing interface 1150 may be an elbow connector, as shown in the example of FIG. 11, which can be placed over the aperture 1140 in the cover 125 to provide a fluid path between the fluid conductor 1145 and the secondary manifold 1105.

[00103] FIG. 12 is an isometric view of an assembled example of the dressing 110 of FIG. 11. As shown in the example of FIG. 12, the cover 125 may be substantially clear or optically transparent, allowing for visualization of the layers of the dressing 110 and through the dressing 110. In example embodiments, the periphery 1135 of the cover 125 extends past the periphery 235 of the first polymer film 205 and the periphery 285 of the second polymer film 215, defining a border region 1205 of the cover 125.

[00104] FIG. 13 is a cross-sectional view of the example dressing 110 of FIG. 12, taken at line 13-13, applied to an example tissue site, and illustrating additional details associated with the therapy system 100 of FIG. 1. In some embodiments, the dressing 110 may be configured to interface with a tissue site 1305. For example, the dressing 110 may be generally configured to be positioned adjacent to the tissue site 1305 and/or in contact with a portion of the tissue site 1305, substantially all of the tissue site 1305, or the tissue site 1305 in its entirety, or tissue around the tissue site 1305. In some examples, the tissue site 1305 may be or may include a defect or targeted treatment site, such as a wound, that may be partially or completely filled or covered by the dressing 110. In various embodiments, the dressing 110 may take many forms, and may have many sizes, shapes, or thicknesses depending on a variety of factors, such as the type of treatment being implemented or the nature and size of the tissue site 1305. For example, the size and the shape of the dressing 110 may be adapted to the contours of deep and irregularly shaped tissue sites and/or may be configured to be adapted to a given shape or contour. Moreover, in some embodiments, any or all of the surfaces of the dressing 110 may comprise projections, or an uneven, coarse, or jagged profile that can, for example, induce strains and stresses on the tissue site 1305, which may be effective to promote granulation at the tissue site 1305. In some embodiments, the tissue site 1305 may comprise a wound 1310 that extends through the epidermis 1315 and into a dermis 1320. In some examples, as shown in FIG. 13, the tissue site 1305 may comprise a wound 1310 which extends through the epidermis 1315 and dermis 1320 and into a subcutaneous tissue 1325.

[00105] In some embodiments, the dressing 110 may be applied to the tissue site 1305 and cover the wound 1310. In illustrative embodiments, the first polymer film 205 may be placed within, over, on, against, or otherwise proximate to the tissue site 1305. For example, at least a portion of the bottom surface 230 of the first polymer film 205 may be placed into within, over, on, against, or otherwise proximate to the wound 1310. The secondary manifold 1105 may be placed over the first polymer film 205 across from the wound 1310 or epidermis 1315. For example, at least a portion of the bottom surface 1115 of the secondary manifold 1105 may be brought into contact with at least a portion of the top surface 275 of the first polymer film 205. The cover 125, which may be coated on at least a portion of the bottom surface 1130 with adhesive 1330 may be positioned over the secondary manifold and the tissue interface 120 such that at least a portion of the bottom surface 1130 or adhesive 1330 is brought into contact with at least a portion of the top surface 1110 of the secondary manifold 1105 and at least a portion of the top surface 275 of the second polymer film 215. In some embodiments, at least a portion of the cover 125 may be adhered to at least a portion of the secondary manifold 1105 and at least a portion of the tissue interface 120. In alternate embodiments, the second polymer film 215 is instead placed into, within, over, on, against, or otherwise proximate to the wound 1310, particularly when the primary manifold 210 has symmetrical major surfaces (and preferably the first polymer film 205 and the second polymer film 215 are identical to each other).

[00106] In some embodiments, adhesive 1330 may be present on the bottom surface 1130 of the cover 125 at the border region 1205 of the cover 125. For example, the border region 1205 of the cover 125 may be adhered to the epidermis 1315 by adhesive 1330. The cover 125 may be sealed to undamaged epidermis 1315 peripheral to the wound 1310 at least at the border region 1205. Thus, the dressing 110 may provide a sealed therapeutic environment 1335 proximate to the wound 1310. The sealed therapeutic environment 1335 may be substantially isolated from the external environment, and the negative-pressure source 105 may be fluidly coupled to the sealed therapeutic environment 1335. For example, dressing interface 1150 may be disposed over or received through the aperture 1140 formed in the cover 125. The dressing interface 1150 may for a fluid seal against the top surface 1125 of the cover 125, for example, by an adhesive seal, and the dressing interface 1150 may be in fluid communication with the sealed therapeutic environment 1335. In example embodiments, the dressing interface 1150 may be fluidly coupled to the negative-pressure source 105 by fluid conductor 1145. In illustrative embodiments, a canister, such as container 115 may be disposed in the fluid path between the dressing interface 1150 and the negative-pressure source 105. Negative pressure may be applied across the wound 1310 by through the secondary manifold 1105 and the first polymer fdm 205 can induce macrostrain and microstrain at the wound 1310, and remove or reduce exudates and other fluids from the tissue site 1305. The removed exudates and other fluids can be collected in the container 115 and disposed of properly. In example embodiments, fluid, moisture, and exudate may travel from the wound 1310 through the fluid passages 220 in the first polymer film 205 and into the windows 240, from the windows 240 through the fluid passages 270 in the second polymer film 215, and through the secondary manifold 1105 and to the dressing interface 1150.

[00107] FIG. 14A is a detail view, taken at reference FIG. 14A in FIG. 13, illustrating details that may be associated with some example embodiments of the dressing 110 and system 100 of FIG. 13. FIG. 14A illustrates embodiments of the dressing 110 where the cover 125 and the second polymer film 215 are not drawn into the window 240. For example, the bottom surface 280 of the second polymer film 215 may remain substantially separated from the top surface 225 of the first polymer film 205. In example embodiments, the second polymer film 215 may be coupled to, for example, welded to at least a portion of the primary manifold 210. In examples where the second polymer film 215 is welded to the primary manifold 210, the welds may substantially prevent the second polymer film 215 and the cover 125 from being drawn into the window 240 under reduced pressure. In illustrative embodiments, the second polymer film 215 may not be coupled to or welded to the primary manifold 210. In examples where the second polymer film 215 is not welded to the primary manifold 210, the second polymer film 215 may not be prevented from being drawn into the window 240. FIG. 14 A may illustrate some embodiments where the second polymer film 215 and the cover 125 are not drawn into the window 240, such as when negative pressure is not provided to the sealed therapeutic environment 1335. For example, the pressure within the sealed therapeutic environment 1335 may be substantially the same as the ambient pressure outside of the dressing 110, such as in the region facing the top surface 1125 of the cover 125. In cases where a pressure gradient is not created across the cover 125 and the second polymer film 215, a resultant force is not created, and the cover 125 and the second polymer film 215 are not drawn into the window 240.

[00108] FIG. 14B illustrates additional details that may be associated with the detail view of FIG. 14A in some embodiments of the dressing 110 and system 100 of FIG. 13. For example, the pressure within the sealed therapeutic environment 1335 may be reduced to a suitable negative pressure, resulting in a low-pressure region within the primary manifold 210, such as within the window 240. In illustrative embodiments, a pressure gradient may be created across the cover 125 and the second polymer film 215, with a region of higher ambient pressure opposite the top surface 1125 of the cover 125 and a region of lower negative pressure opposite the bottom surface 280 of the second polymer film 215. A resultant force from the pressure differential across the cover 125 and the second polymer film 215 may draw at least a portion of the cover 125 and the second polymer film 215 into the window 240. For example, a portion of the bottom surface 280 of the second polymer fdm 215 may be brought into contact with the top surface 225 of the first polymer film 205. In illustrative embodiments, at least a portion of the bottom surface of the first polymer fdm 205 may be in contact with the epidermis 1315 or the wound 1310 (not shown in FIG. 14B). In some embodiments, the cover 125, the adhesive 1330, the second polymer film 215, and the first polymer film 205 may be substantially clear or optically transparent, and exhibit a substantially similar refractive index. In example embodiments, the primary manifold 210 may be sufficiendy stiff in a direction approximately normal to the plane formed by the top surface 1125 of the cover 125 to resist compaction or deformation under negative pressure.

[00109] In operation, negative pressure may be provided to the wound 1310, and/or fluid may be removed from the wound 1310 from the sealed therapeutic environment 1335 by the negativepressure source 105. For example, fluid may travel from the wound 1310 through at least one of the fluid passages 220, first plurality of perforations 2005, second plurality of perforations 2010, third plurality of perforations 2805, fourth plurality of perforations 2810, fifth plurality of perforations 2815, and/or sixth plurality of perforations 2820 into the portion of the sealed therapeutic environment 1335 defined by the space between the top surface 225 of the first polymer film 205, the bottom surface 260 of the primary manifold 210, and the standoffs 905. Fluid may then travel through the windows 240 and into the portion of the sealed therapeutic environment 1335 defined by the space between top surface 255 of the primary manifold 210, the bottom surface 280 of the second polymer film 215, and the boss 1605. Fluid may then travel through the aperture 1745 and into the portion of the sealed therapeutic environment 1335 defined as the space between the top surface 275 of the second polymer film 215, the bottom surface 1765 of the connector drape 1755, the surfaces of the dressing interface 1150 facing the secondary manifold 1105, and/or within the empty spaces of the secondary manifold 1105. Fluid may be removed from the dressing 110 through the dressing interface 1150, and optionally be collected within the container 115.

Exemplary Embodiments

[00110] In a first embodiment, the present disclosure provides an apparatus for treating a tissue site with negative pressure. The apparatus comprises a first polymer film having a plurality of first perforations; a primary manifold adjacent to the first polymer film; and a second polymer film adjacent to the primary manifold and having a plurality of second perforations. The primary manifold comprises a plurality of primary nodes and a plurality of links, the primary nodes and the links being interconnected to define a grid of windows that are transparent. The first polymer film is bonded to the second polymer film at least partially around a periphery of the apparatus and wherein the first polymer film is bonded to the second polymer film in a center window of the primary manifold.

[00111] In a second embodiment, the present disclosure provides an apparatus according to the first embodiment, wherein the first polymer film and the second polymer film are bonded together in a plurality of the windows of the primary manifold.

[00112] In a third embodiment, the present disclosure provides an apparatus according to the first embodiment or the second embodiment, wherein the primary manifold comprises a polymer having a hardness in a range of Shore 10A to Shore 40A.

[00113] In a fourth embodiment, the present disclosure provides an apparatus according to any of the first through third embodiments, wherein the primary manifold comprises polyurethane or silicone having a hardness in a range of Shore 10A to Shore 40 A.

[00114] In a fifth embodiment, the present disclosure provides an apparatus according to any of the first through fourth embodiments, wherein the primary manifold is free of a porous foam.

[00115] In a sixth embodiment, the present disclosure provides an apparatus according to any of the first through fifth embodiments, wherein the windows are open apertures. [00116] In a seventh embodiment, the present disclosure provides an apparatus according to any of the first through sixth embodiments, wherein the windows have at least one of a polygonal or circular frame.

[00117] In an eighth embodiment, the present disclosure provides an apparatus according to any of the first through seventh embodiments, wherein the grid of windows comprises a plurality of different shapes of windows.

[00118] In a ninth embodiment, the present disclosure provides an apparatus according to any of the first through eighth embodiments, wherein the primary manifold has a first major side that is symmetrical to an opposing second major side.

[00119] In a tenth embodiment, the present disclosure provides an apparatus according to any of the first through ninth embodiments, wherein each of the primary nodes comprises a standoff.

[00120] In an eleventh embodiment, the present disclosure provides an apparatus according to the tenth embodiment, wherein the standoff comprises a spherical member that has a diameter in a range of about 4 millimeters to about 12 millimeters.

[00121] In a twelfth embodiment, the present disclosure provides an apparatus according to any of the first through eleventh embodiments, wherein: the first polymer film has a first thickness; the second polymer film has a second thickness; and the first thickness is greater than the second thickness.

[00122] In a thirteenth embodiment, the present disclosure provides an apparatus according to the twelfth embodiment, wherein the second thickness is in a range of about 10 micrometers to about 500 micrometers.

[00123] In a fourteenth embodiment, the present disclosure provides an apparatus according to any of the first through thirteenth embodiments, wherein the primary manifold is bonded to at least one of the first polymer film or the second polymer film.

[00124] In a fifteenth embodiment, the present disclosure provides an apparatus according to any of the first through fourteenth embodiments, wherein the first polymer film is bonded to the second polymer film all the way around the periphery of the apparatus.

[00125] In a sixteenth embodiment, the present disclosure provides an apparatus according to any of the first through fifteenth embodiments, wherein each of the windows has a width of at least 8 millimeters.

[00126] In a seventeenth embodiment, the present disclosure provides an apparatus according to any of the first through sixteenth embodiments, wherein each of the windows independently has a width in a range of about 8 millimeters to about 15 millimeters.

[00127] In an eighteenth embodiment, the present disclosure provides an apparatus according to any of the first through seventeenth embodiments, wherein each of the links has a width of about 2 millimeters. [00128] In a nineteenth embodiment, the present disclosure provides an apparatus according to any of the first through eighteenth embodiments, wherein the first perforations comprise a plurality of slots, each of the slots having a length less than 5 millimeters.

[00129] In a twentieth embodiment, the present disclosure provides an apparatus according to any of the first through nineteenth embodiments, wherein the first perforations comprise a plurality of slots, each of the slots having a length less than 5 millimeters and a width less than 2 millimeters.

[00130] In a twenty -first embodiment, the present disclosure provides an apparatus according to any of the first through twentieth embodiments, wherein the first perforations comprise a plurality of slots, each of the slots having a length of about 2 millimeters to about 5 millimeters and a width of about 0.5 millimeters to about 2 millimeters.

[00131] In a twenty -second embodiment, the present disclosure provides an apparatus according to any of the first through twenty -first embodiments, wherein the first perforations comprise a plurality of slits, each of the slits having a length less than 5 millimeters.

[00132] In a twenty -third embodiment, the present disclosure provides an apparatus according to any of the first through twenty-second embodiments, wherein the first perforations comprise a plurality of slits, each of the slits having a length of about 2 millimeters to about 5 millimeters.

[00133] In a twenty -fourth embodiment, the present disclosure provides an apparatus according to any of the first through twenty -third embodiments, further comprising a cover configured to be disposed over the either of the first polymer film or the second polymer film.

[00134] In a twenty -fifth embodiment, the present disclosure provides an apparatus according to any of the first through twenty -fourth embodiments, further comprising a negative-pressure source configured to be fluidly coupled to the primary manifold.

[00135] In a twenty-sixth embodiment, the present disclosure provides a system for treating a tissue site with negative pressure. The system comprises a dressing configured to be placed adjacent to the tissue site and a secondary manifold configured to be positioned adjacent the dressing opposite the tissue site. The system further comprises a drape configured to be positioned over the dressing and the secondary manifold and seal to tissue adjacent to the tissue site to form a sealed space and a negative-pressure source configured to provide negative pressure to the sealed space. The dressing comprises the apparatus according to any of the first through twenty -fifth embodiments.

[00136] In a twenty -seventh embodiment, the present disclosure provides a system according to the twenty-sixth embodiment, wherein the first polymer fdm is configured to be positioned adjacent to the tissue site.

[00137] In a twenty -eighth embodiment, the present disclosure provides a system according to the twenty-seventh embodiment, wherein the secondary manifold is configured to be positioned adjacent to the second polymer film. [00138] In a twenty -ninth embodiment, the present disclosure provides a system according to the twenty -eighth embodiment, wherein a portion of the drape is configured to be positioned adjacent to a portion of the second polymer film.

[00139] In a thirtieth embodiment, the present disclosure provides a system according to the twentyninth embodiment, wherein the secondary manifold is configured to be positioned between the drape and the second polymer film.

[00140] In a thirty -first embodiment, the present disclosure provides a method of treating a tissue site with negative pressure. The method comprises applying a dressing to the tissue site; positioning a secondary manifold over the dressing; placing a drape over the dressing and the secondary manifold; and sealing the drape to tissue adjacent to the tissue site to form a sealed space beneath the cover. The method further comprises applying therapeutic levels of negative pressure to the tissue site through the dressing and observing the tissue site through the windows to evaluate a state of the tissue site. The dressing comprises an apparatus according to any of the first through twenty -fifth embodiments. [00141] In a thirty-second embodiment, the present disclosure provides a method according to the thirty-second embodiment, further comprising the step of drawing the second film layer into contact with the first film layer within at least one of the plurality of windows.

[00142] While shown in a few illustrative embodiments, a person having ordinary skill in the art will recognize that the systems, apparatuses, and methods described herein are susceptible to various changes and modifications that fall within the scope of the appended claims. Moreover, descriptions of various alternatives using terms such as “or” do not require mutual exclusivity unless clearly required by the context, and the indefinite articles “a” or “an” do not limit the subject to a single instance unless clearly required by the context. Components may be also be combined or eliminated in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations the dressing 110, the container 115, tissue interface 120, cover 125, or any combination of components may be eliminated or separated from other components for manufacture or sale. In other example configurations, the controller 130 may also be manufactured, configured, assembled, or sold independently of other components. Further 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 defined by the appended claims.

Claims

CLAIMS What is claimed is:

1. An apparatus for treating a tissue site with negative pressure, the apparatus comprising: a first polymer film having a plurality of first perforations; a primary manifold adjacent to the first polymer fdm, the primary manifold comprising a plurality of primary nodes and a plurality of links, the primary nodes and the links being interconnected to define a grid of windows that are transparent; and a second polymer film adjacent to the primary manifold, the second polymer film having a plurality of second perforations, wherein the first polymer film is bonded to the second polymer fdm at least partially around a periphery of the apparatus and wherein the first polymer film is bonded to the second polymer film in a center window of the primary manifold.

2. The apparatus of claim 1, wherein the first polymer film and the second polymer film are bonded together in a plurality of the windows of the primary manifold.

3. The apparatus of any preceding claim, wherein the primary manifold comprises a polymer having a hardness in a range of Shore 10A to Shore 40 A.

4. The apparatus of any preceding claim, wherein the primary manifold comprises polyurethane or silicone having a hardness in a range of Shore 10A to Shore 40 A.

5. The apparatus of any preceding claim, wherein the primary manifold is free of a porous foam.

6. The apparatus of any preceding claim, wherein the windows are open apertures.

7. The apparatus of any preceding claim, wherein the windows have at least one of a polygonal or circular frame.

8. The apparatus of any preceding claim, wherein the grid of windows comprises a plurality of different shapes of windows.

9. The apparatus of any preceding claim, wherein the primary manifold has a first major side that is symmetrical to an opposing second major side.

10. The apparatus of any preceding claim, wherein each of the primary nodes comprises a standoff.

11. The apparatus of claim 10, wherein the standoff comprises a spherical member that has a diameter in a range of about 4 millimeters to about 12 millimeters.

12. The apparatus of any preceding claim, wherein: the first polymer film has a first thickness; the second polymer film has a second thickness; and the first thickness is greater than the second thickness.

13. The apparatus of claim 12, wherein the second thickness is in a range of about 10 micrometers to about 500 micrometers.

14. The apparatus of any preceding claim, wherein the primary manifold is bonded to at least one of the first polymer film or the second polymer film.

15. The apparatus of any preceding claim, wherein the first polymer film is bonded to the second polymer film all the way around the periphery of the apparatus.

16. The apparatus of any preceding claim, wherein each of the windows has a width of at least 8 millimeters.

17. The apparatus of any preceding claim, wherein each of the windows independently has a width in a range of about 8 millimeters to about 15 millimeters.

18. The apparatus of any preceding claim, wherein each of the links has a width of about 2 millimeters.

19. The apparatus of any preceding claim, wherein the first perforations comprise a plurality of slots, each of the slots having a length less than 5 millimeters.

20. The apparatus of any preceding claim, wherein the first perforations comprise a plurality of slots, each of the slots having a length less than 5 millimeters and a width less than 2 millimeters.

21. The apparatus of any preceding claim, wherein the first perforations comprise a plurality of slots, each of the slots having a length of about 2 millimeters to about 5 millimeters and a width of about 0.5 millimeters to about 2 millimeters.

22. The apparatus of any preceding claim, wherein the first perforations comprise a plurality of slits, each of the slits having a length less than 5 millimeters.

23. The apparatus of any preceding claim, wherein the first perforations comprise a plurality of slits, each of the slits having a length of about 2 millimeters to about 5 millimeters.

24. A system for treating a tissue site with negative pressure, comprising: a dressing configured to be placed adjacent to the tissue site, the dressing comprising the apparatus of any of claims 1 to 23; a secondary manifold configured to be positioned adjacent the dressing opposite the tissue site; a drape configured to be positioned over the dressing and the secondary manifold and seal to tissue adjacent to the tissue site to form a sealed space; and a negative-pressure source configured to provide negative pressure to the sealed space.

25. The system of claim 24, wherein the first polymer film is configured to be positioned adjacent to the tissue site.

26. The system of claim 25, wherein the secondary manifold is configured to be positioned adjacent to the second polymer film.

27. The system of claim 26, wherein a portion of the drape is configured to be positioned adjacent to a portion of the second polymer film.

28. The system of claim 27, wherein the secondary manifold is configured to be positioned between the drape and the second polymer film.

29. A method of treating a tissue site with negative pressure, the method comprising: applying a dressing to the tissue site, the dressing comprising an apparatus of any of claims 1 to 23 : positioning a secondary manifold over the dressing; placing a drape over the dressing and the secondary manifold; sealing the drape to tissue adjacent to the tissue site to form a sealed space beneath the cover; applying therapeutic levels of negative pressure to the tissue site through the dressing; and observing the tissue site through the windows to evaluate a state of the tissue site.

30. The method of claim 29, further comprising the step of drawing the second polymer film into contact with the first polymer film within at least one of the plurality of windows.