WO2021148925A1

WO2021148925A1 - Customizable negative-pressure tissue interface with edge protection

Info

Publication number: WO2021148925A1
Application number: PCT/IB2021/050344
Authority: WO
Inventors: Benjamin Andrew Pratt; Christopher Brian Locke
Original assignee: Kci Licensing, Inc.
Priority date: 2020-01-21
Filing date: 2021-01-18
Publication date: 2021-07-29

Abstract

A dressing for treating a tissue site may comprise a tissue interface having at least a first layer and a second layer. The first layer may comprise a polymer film having a first singulation border, and the second layer may comprise a manifold having an edge and a second singulation border. The second singulation border may be offset from the first singulation border such that the first singulation border is closer to the edge of the manifold than the second singulation border. The first singulation border and the second singulation border can be configured to allow first portions of the polymer film and the manifold to be separated from second portions of the polymer film and the manifold. In some examples, the polymer film may form a margin around the edge of the manifold after separation.

Description

CUSTOMIZABLE NEGATIVE-PRESSURE TISSUE INTERFACE WITH EDGE

PROTECTION

TECHNICAL FIELD

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 62/963,785, filed on January 21, 2020, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The invention set forth in the appended claims relates generally to tissue treatment systems and more particularly, but without limitation, to dressings for tissue treatment and methods of using the dressings for tissue treatment.

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.

BRIEF SUMMARY

[0006] New and useful systems, apparatuses, and methods for treating a tissue site 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] For example, in some embodiments, a tissue interface for treating a tissue site may comprise a contact layer and a manifold, and each may have pre-cut perforations that can allow the tissue interface to be manually sized. The perforations may be partial perforations or full perforations. The perforations in the contact layer and the manifold may be mis-aligned so that the area of the contact layer is greater than the area of the manifold after separation, which can reduce exposure of the manifold to the tissue site after separation.

[0008] The perforations may be cut in a variety of patterns suitable for customizing the size or shape of the tissue interface . For example, the perforations may be cut as parallel curves or lines, spirals, squares, rectangles, triangles, and hexagons.

[0009] In some examples, the contact layer may be completely perforated in the area of singulation, and the manifold may be kiss-cut or otherwise partially perforated through about 80% of its thickness in the same region and pattern. In other examples, the manifold may be cut completely through in sections, with bridges between cuts to maintain structural integrity.

[0010] The contact layer may also have structural tags, which can reduce gapping and exposure of the manifold. In some examples, the contact layer may be partially perforated to reduce the strength of the contact layer in the area of singulation.

[0011] Some embodiments of the tissue interface may also comprise a pattern adhesive that bonds the contact layer to the manifold. The pattern of the adhesive may be configured so that portions of the manifold adjacent to overlapping portions of the contact layer are not bonded, which can facilitate singulation. Adhesives such as acrylic and polyurethane gel may be suitable for some embodiments.

[0012] More generally, a dressing for treating a tissue site may comprise a tissue interface having at least a first layer and a second layer. The first layer may comprise a polymer film having a first singulation border, and the second layer may comprise a manifold having an edge and a second singulation border. The second singulation border may be offset from the first singulation border such that the first singulation border is closer to the edge of the manifold than the second singulation border. The manifold may comprise a polymer foam in some embodiments. For example, the manifold may comprise a reticulated polyurethane ether foam. The first singulation border and the second singulation border can be configured to allow first portions of the polymer film and the manifold to be separated from second portions of the polymer film and the manifold. In some examples, the polymer film may form a margin around the edge of the manifold after separation.

[0013] In more particular examples, the first singulation border may comprise a plurality of first separation segments arranged in a first pattern, and the second singulation border may comprise a plurality of second separation segments arranged in a second pattern. The second pattern may be geometrically similar to the first pattern.

[0014] Other examples of a tissue interface for treating a tissue site with negative pressure may comprise a contact layer having a first singulation border, and a manifold laminated to the contact layer. The manifold may have an edge and a second singulation border, and the first singulation border may be closer to the edge than the second singulation border. The first singulation border and the second singulation border may be arranged in patterns having similar shapes, which may not be congruent. For example, the patterns may comprise parallel lines or curves. In some examples, the first singulation border may be offset from the second singulation border by a distance of about 50% of the thickness of the manifold. A distance in a range of about 2-3 millimeters may be suitable for some embodiments.

[0015] In some embodiments, the first singulation border may comprise a plurality of partial or full perforations in the contact layer. The second singulation border may comprise a plurality of partial or full perforations through the manifold.

[0016] In more particular embodiments, the manifold may comprise foam having open cells. The foam may be hydrophobic in some embodiments. In some embodiments, the contact layer may comprises or consist essentially of a polymer film, such as a polyurethane or polyethylene film.

[0017] Alternatively, other example embodiments may include a method of using the dressing for treating a tissue site. Generally, the method may comprise applying the dressing to the tissue site and applying negative pressure to the dressing. In more particular examples, the tissue interface may be sized along the first singulation border and the second singulation border, wherein the film forms a margin around an edge of the manifold after sizing. In some embodiments, the tissue interface may be sized by hand, without tools. For example, the tissue interface may be tom along the singulation borders. The tissue interface may be applied to the tissue site so that the film is disposed between the manifold and the tissue site. In some examples, the film may contact the tissue site and/or epidermis adjacent to the tissue site and may provide a margin around the manifold. A drape or other suitable cover may be placed over the manifold and sealed to an attachment surface to isolate the tissue interface and the tissue site from the external environment. A fluid conductor may be fluidly coupled to the tissue interface through the drape. A negative-pressure source may be fluidly coupled to the fluid conductor, and negative pressure from the negative-pressure source may be applied at therapeutic levels to the manifold through the fluid conductor.

[0018] In some embodiments, a tissue interface of a dressing for treating a tissue site may be manufactured by providing a polymer film and a manifold, forming a plurality of first perforations in the polymer film in a first pattern, and forming a plurality of second perforations in the manifold in a second pattern offset from the first pattern. The manifold may be placed adjacent to the polymer film, and may be bonded to at least some portion of the polymer film in some examples. In more particular embodiments, the first perforations may be cut through the polymer film from a first side to a second side, leaving bridges in the first pattern that are not cut. In other embodiments, the first perforations may be cut about 80% through the polymer film. The second perforations may also be cut through the manifold from a first side to a second side in some embodiments, leaving bridges in the second pattern that are not cut. In other embodiments, the second perforations may be cut through about 80% of the manifold.

[0019] Various embodiments may provide significant advantages and benefits. For example, some embodiments of the dressing may be sized without the need for tools, and can provide a protective border around the edge of singulated manifold material, which substantially prevent direct contact between skin and manifold material. Other 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

[0020] Figure 1 is a functional block diagram of an example embodiment of a therapy system that can provide negative-pressure treatment and instillation treatment in accordance with this specification;

[0021] Figure 2 is an assembly view of an example of a tissue interface that can be associated with some embodiments of the therapy system of Figure 1;

[0022] Figure 3 is a schematic view of an example layer that can be associated with some embodiments of the tissue interface of Figure 2;

[0023] Figure 4 is a side view of an example of the tissue interface of Figure 2;

[0024] Figure 5 is an assembly view of an example of a dressing that can be associated with some embodiments of the therapy system of Figure 1;

[0025] Figure 6 is a schematic view of an example layer that can be associated with some embodiments of the dressing of Figure 5;

[0026] Figure 7 is a schematic view of the example layer of Figure 6 overlaid on the example layer of Figure 3;

[0027] Figure 8 is an assembly view of another example of a tissue interface that may be associated with some embodiments of the therapy system of Figure 1;

[0028] Figure 9 is a top view of another example of a tissue interface that may be associated with some embodiments of the therapy system of Figure 1;

[0029] Figure 10 is a section view of the tissue interface of Figure 9;

[0030] Figure 11 is a top view of another embodiment of a tissue interface;

[0031] Figure 12 illustrates one method of sizing a tissue interface; and [0032] Figure 13 is a schematic diagram of an example of the therapy system of Figure 1 applied to a tissue site.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0033] 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.

[0034] The example embodiments may also be described herein with reference to spatial relationships between various elements or to the spatial orientation of various elements depicted in the attached drawings. In general, such relationships or orientation assume a frame of reference consistent with or relative to a patient in a position to receive treatment. However, as should be recognized by those skilled in the art, this frame of reference is merely a descriptive expedient rather than a strict prescription.

[0035] Figure 1 is a simplified functional 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.

[0036] 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, a surface wound, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. 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. A surface wound, as used herein, is a wound on the surface of a body that is exposed to the outer surface of the body, such as an injury or damage to the epidermis, dermis, and/or subcutaneous layers. Surface wounds may include ulcers or closed incisions, for example. A surface wound, as used herein, does not include wounds within an intra-abdominal cavity. 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.

[0037] 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 Figure 1, the dressing 110 may comprise or consist essentially of a tissue interface 120, a cover 125, or both in some embodiments. [0038] 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 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.

[0039] 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 Figure 1, for example, the therapy system 100 may include a first sensor 135 and a second sensor 140 coupled to the controller 130.

[0040] 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 Figure 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 Figure 1.

[0041] 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.

[0042] 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.

[0043] 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” 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).

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The tissue interface 120 can be generally adapted to partially or fully contact a tissue site. The tissue interface 120 may take many forms, and may have many sizes, shapes, or thicknesses, depending on a variety of factors, such as the type of treatment being implemented or the nature and size of a tissue site. For example, the size and shape of the tissue interface 120 may be adapted to the contours of deep and irregular shaped tissue sites. Any or all of the surfaces of the tissue interface 120 may have an uneven, coarse, or jagged profile.

[0048] 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 through multiple apertures 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.

[0049] In some embodiments, the cover 125 may provide a bacterial barrier and protection from physical trauma. The cover 125 may also be constructed from a material that can reduce evaporative 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 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.

[0050] In some example embodiments, the cover 125 may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. The cover 125 may comprise, for example, one or more of the following materials: polyurethane (PU), such as hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl acetate (EVA); co-polyester; and polyether block polyamide copolymers. Such materials are commercially available as, for example, TEGADERM drape, commercially available from 3M Company, Minneapolis Minnesota; polyurethane (PU) drape, commercially available from Avery Dennison Corporation, Pasadena, California; polyether block polyamide copolymer (PEBAX), for example, from Arkema S.A., Colombes, France; and Inspire 2301 and Inpsire 2327 polyurethane fdms, commercially available from Transcontinental Advanced Coating, Wrexham, United Kingdom. In some embodiments, the cover 125 may comprise INSPIRE 2301 having an MVTR (upright cup technique) of 2600 g/m²/24 hours and a thickness of about 30 microns.

[0051] 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.). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Other example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.

[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 and sealed to an attachment surface near a tissue site. For example, 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 provided to the tissue interface 120. Such data may include the type of 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 160 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. Alternatively, the application of negative pressure may be implemented to provide an intermittent mode of operation to allow instillation solution to dwell at 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] Figure 2 is an assembly view of an example of the tissue interface 120 of Figure 1, illustrating additional details that may be associated with some embodiments. For example, some embodiments of the tissue interface 120 may have more than one layer. In the example of Figure 2, the tissue interface comprises a first layer 205 and a second layer 210.

[0065] The first layer 205 may comprise or consist essentially of a liquid-impermeable, elastomeric material. For example, the first layer 205 may comprise or consist essentially of a polymer film, such as a polyurethane film. In some embodiments, the first layer 205 may comprise or consist essentially of the same material as the cover 125. The first layer 205 may also have a smooth or matte surface texture in some embodiments. A glossy or shiny finish finer or equal to a grade B3 according to the SPI (Society of the 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 layer 205 may have a substantially flat surface, with height variations limited to 0.2 millimeters over a centimeter.

[0066] In some embodiments, the first layer 205 may be hydrophobic. The hydrophobicity of the first layer 205 may vary, but may have a contact angle with water of at least ninety degrees in some embodiments. In some embodiments the first layer 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 layer 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 can be measured using 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, liquid dropper such as a syringe, 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 FTAl25, 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 lowest measured values. The hydrophobicity of the first layer 205 may be further enhanced with a hydrophobic coating of other materials, such as silicones and fluorocarbons, either as coated from a liquid, or plasma coated.

[0067] The first layer 205 may also be suitable for welding to other layers, including the second layer 210. For example, the first layer 205 may be adapted for welding to polyurethane foams using heat, radio frequency (RF) welding, or other methods to generate heat 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.

[0068] The area density of the first layer 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.

[0069] In some embodiments, for example, the first layer 205 may comprise or consist essentially of 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 20 microns and 100 microns may be suitable for many applications. Films may be clear, colored, or printed. More polar films suitable for laminating to a polyethylene film include polyamide, co-polyesters, 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.

[0070] In some embodiments, the first layer 205 may comprise a means for controlling fluid movement through the first layer 205. For example, the first layer 205 may have one or more passages 215, which can be distributed uniformly or randomly across the first layer 205. The passages 215 may be bi-directional and pressure-responsive. For example, each of the passages 215 generally may comprise or consist essentially of an elastic passage that is normally unstrained to substantially reduce liquid flow, and can expand or open in response to a pressure gradient. As illustrated in the example of Figure 2, the passages 215 may comprise or consist essentially of perforations in the first layer 205. The perforations may be formed by removing material from the first layer 205. For example, perforations may be formed by cutting through the first layer 205. In the absence of a pressure gradient across the perforations, the perforations 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 215 may be or may function as an elastomeric valve that is normally closed when unstrained to substantially prevent liquid flow, and can open in response to a pressure gradient. In some examples, the passages 215 may comprise or consist essentially of fenestrations in the first layer 205. Generally, fenestrations are a species of perforation, and may also be formed by removing material from the first layer 205. The amount of material removed and the resulting dimensions of the fenestrations may be up to an order of magnitude less than perforations.

[0071] In some embodiments, the perforations may be formed as slots, slits, or a combination of slots and slits in the first layer 205. In some examples, the perforations may comprise or consist of linear slots having a length less than 4 millimeters and a width less than 1 millimeter. The length may be at least 2 millimeters, and the width may be at least 0.4 millimeters in some embodiments. A length of about 3 millimeters and a width of about 0.8 millimeters may be particularly suitable for many applications, and a tolerance of about 0.1 millimeter may also be acceptable. Such dimensions and tolerances may be achieved with a laser cutter, for example. Slots of such configurations may function as imperfect elastomeric valves that can 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.

[0072] Additionally, the first layer 205 may comprise one or more singulation borders. For example, the first layer 205 of Figure 2 has a singulation border that consists essentially of a first separation line 220, which may extend from a first edge of the first layer 205 to a second edge of the first layer 205. In some embodiments, a singulation border may comprise or consist essentially of a plurality of separation segments. For example, the first separation line 220 may comprise a plurality of separation segments 225. Each of the separation segments 225 may comprise or consist essentially of a perforation, fenestration, indentation, or other means for locally decreasing the tear strength of the first layer 205 along the first separation line 220. For example, the first separation line 220 of Figure 2 may comprise collinear slits or slots so that the first separation line 220 forms a straight line across the first layer 205. In other examples, the separation segments 225 may comprise partial or kiss-cut perforations that form a line across the first layer 205.

[0073] In some examples, the separation segments 225 may be formed by cutting through the first layer 205 in a pattern, leaving bridges between the cuts. The cut may be a partial cut in some embodiments. For example, the cut may only penetrate about 80% of the first layer 205 in some embodiments.

[0074] The second layer 210 generally comprises or consists essentially of a manifold, which can provide a means for collecting or distributing fluid across the tissue interface 120 under pressure. For example, the second layer 210 may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures 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 from a source of instillation solution, across the tissue interface 120.

[0075] In some illustrative embodiments, the pathways of the second layer 210 may be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, the second layer 210 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 interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, the second layer 210 may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, the second layer 210 may be molded to provide surface projections that define interconnected fluid pathways.

[0076] In some embodiments, the second layer 210 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 second layer 210 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 second layer 210 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 second layer 210 may be at least 10 pounds per square inch. The second layer 210 may have a tear strength of at least 2.5 pounds per inch. In some embodiments, the second layer 210 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 second layer 210 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.

[0077] Other suitable materials for the second layer 210 may include non-woven fabrics; three- dimensional (3D) polymeric structures, such as molded polymers, embossed and formed films, and fusion-bonded films (such as manufactured by Supracor, Inc.), and mesh, for example. [0078] In some examples, the second layer 210 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 second layer 210 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 puncture-resistant 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 second layer 210 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.

[0079] Additionally, the second layer 210 may comprise at least one singulation border. In general, it may be advantageous for the number of singulation borders in the second layer to be equal to the number of singulation borders in the first layer 205. In Figure 2, the second layer 210 has a singulation border that consists essentially of a second separation line 230, which may extend from a first edge of the second layer 210 to a second edge of the second layer 210. In some embodiments, the second separation line 230 may comprise a plurality of separation segments 235. Each of the separation segments 235 may comprise or consist essentially of a perforation, fenestration, indentation or other means for locally decreasing the tear strength of the second layer 210 along the second separation line 230. For example, the second separation line 230 of Figure 2 may comprise collinear slits or slots so that the second separation line 230 forms a straight line across the second layer 210. In other examples, the second separation line 230 may comprise one or more partial perforations.

[0080] The separation segments 235 may be arranged in a pattern that is geometrically similar to the pattern of the separation segments 225 in some embodiments. The patterns may not be congruent. For example, the separation segments 225 and the separation segments 235 may both be arranged so that the first separation line 220 and the second separation line 230 form parallel lines.

[0081] In some examples, the separation segments 235 may be formed by cutting through the second layer 210 in a pattern, leaving bridges between the cuts. The cut may be a partial cut in some embodiments. For example, the cut may only penetrate about 80% of the second layer 210 in some embodiments. [0082] Figure 3 is a schematic view of another example of the first layer 205, illustrating additional details that may be associated with some embodiments. As illustrated in the example of Figure 3, the passages 215 may each consist essentially of one or more linear slots having a length L. A length L of about 3 millimeters may be suitable for some examples. Figure 3 additionally illustrates an example of a uniform distribution pattern of the passages 215. In Figure 3, the passages 215 are substantially coextensive with the first layer 205, and are distributed across the first layer 205 in a grid of parallel rows and columns, in which the slots are also mutually parallel to each other. The rows may be spaced a distance Dl, and the passages 215 within each of the rows may be spaced a distance D2. For example, a distance D 1 of about 3 millimeters on center and a distance D2 of about 3 millimeters on center may be suitable for some embodiments. The passages 215 in adjacent rows may be aligned or offset. For example, adjacent rows may be offset, as illustrated in Figure 3, so that the passages 215 are aligned in alternating rows and separated by a distance D3. A distance D3 of about 6 millimeters may be suitable for some examples. The spacing of the passages 215 may vary in some embodiments to increase the density of the passages 215 according to therapeutic requirements.

[0083] Figure 3 also illustrates an example configuration of the first separation line 220. In the example of Figure 3, the separation segments 225 are generally straight and may be arranged in a collinear pattern parallel to the rows of the passages 215. One or more of the separation segments 225 may have a length L2, which may be substantially longer than the length LI so that the tear strength of the first layer 205 is less along the first separation line 220 than along the passages 215.

[0084] Figure 4 is a side view of an example of the tissue interface 120 of Figure 2 that may be associated with some embodiments of the therapy system of Figure 1. In some embodiments, the first layer 205 may be disposed adjacent to the second layer 210. For example, the first layer 205 and the second layer 210 may be stacked so that the first layer 205 is in contact with the second layer 210. The first layer 205 may also be heat-bonded or adhered to the second layer 210 in some embodiments. In some embodiments, the first layer 205 optionally includes a low-tack adhesive opposite the second layer 210. The low-tack adhesive may be continuously coated on the first layer 205 or applied in a pattern.

[0085] The second layer 210 generally has a first planar surface and a second planar surface opposite the first planar surface. A thickness T of the second layer 210 between the first planar surface and the second planar surface may also vary according to needs of a prescribed therapy. For example, the thickness T of the second layer 210 may be decreased to relieve stress on other layers and to reduce tension on peripheral tissue. The thickness of the second layer 210 can also affect the conformability of the second layer 210. In some embodiments, a suitable foam may have a thickness T in a range of about 5 millimeters to 10 millimeters. Fabrics, including suitable 3D textiles and spacer fabrics, may have a thickness T in a range of about 2 millimeters to about 8 millimeters.

[0086] As shown in Figure 4, the first separation line 220 may be staggered or otherwise offset from the second separation line 230 by an offset distance d, and the first separation line 220 may be closer to at least one edge of the second layer 210 than the second separation line 230. For example, the first separation line 220 may be closer to an edge 405 than the second separation line 230 by the distance d. In some embodiments, the distance d may be about one-half the thickness T. A distance d of about 2-3 millimeters may be suitable for some embodiments. Additionally, or alternatively, the first layer 205 may extend past the edge 405 to form a margin 410 around the edge 405.

[0087] Figure 5 is an assembly view of example of the dressing 110 of Figure 1, illustrating additional details that may be associated with some embodiments in which the tissue interface 120 may comprise additional layers. In the example of Figure 5, the tissue interface 120 comprises a third layer 505, in addition to the first layer 205 and the second layer 210 of Figure 2. In some embodiments, the third layer 505 may be adj acent to the first layer 205 opposite the second layer 210. The third layer 505 may also be bonded to the first layer 205 in some embodiments. Figure 5 also illustrates an example of the cover 125, which may be disposed over or adjacent to the second layer 210. In some embodiments, the cover 125 may have a shape that is similar to the shape of the first layer 205 or the second layer 210.

[0088] The third layer 505 may comprise or consist essentially of a sealing layer formed from a soft, pliable material, such as a tacky gel, suitable for providing a fluid seal around a tissue site, and may have a substantially flat surface. For example, the third layer 505 may comprise, 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. The third layer 505 may include an adhesive surface on an underside and a patterned coating of acrylic on a top side. The patterned coating of acrylic may be applied about a peripheral area to allow higher bonding in regions that are likely to be in contact with skin rather than the wound area. In other embodiments, the third layer 505 may comprise a low-tack adhesive layer instead of silicone. In some embodiments, the third layer 505 may have a thickness between about 200 microns (pm) and about 1000 microns (pm). In some embodiments, the third layer 505 may have a hardness between about 5 Shore OO and about 80 Shore OO. Further, the third layer 505 may be comprised of hydrophobic or hydrophilic materials.

[0089] In some embodiments, the third layer 505 may be a hydrophobic-coated material. For example, the third layer 505 may be formed by coating a porous 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.

[0090] The third layer 505 may have comers 510 and edges 515. The third layer 505 may include apertures 520. The apertures 520 may be formed by cutting or by application of local RF or ultrasonic energy, for example, or by other suitable techniques for forming an opening. The apertures 520 may have a uniform distribution pattern, or may be randomly distributed on the third layer 505. The apertures 520 in the third layer 505 may have many shapes, including circles, squares, stars, ovals, polygons, slits, complex curves, rectilinear shapes, triangles, for example, or may have some combination of such shapes.

[0091] Each of the apertures 520 may have uniform or similar geometric properties. For example, in some embodiments, each of the apertures 520 may be circular apertures, having substantially the same diameter. In some embodiments, the diameter of each of the apertures 520 may be between about 1 millimeter and about 50 millimeters. In other embodiments, the diameter of each of the apertures 520 may be between about 1 millimeter and about 20 millimeters.

[0092] In other embodiments, geometric properties of the apertures 520 may vary. For example, the diameter of the apertures 520 may vary depending on the position of the apertures 520 in the third layer 505. For example, the apertures 520 in a central area of the third layer may be substantially larger than the apertures 520 in a peripheral portion. The apertures 520 may be spaced substantially equidistant over the third layer 505. Alternatively, the spacing of the apertures 520 may be irregular.

[0093] As illustrated in the example of Figure 5, some embodiments of the dressing 110 may include a release liner 525 to protect the third layer 505 prior to use. The release liner 525 may also provide stiffness to facilitate handling and applying the dressing 110. The release liner 525 may be, for example, a casting paper, a fdm, or polyethylene. Further, in some embodiments, the release liner 525 may be a polyester material such as polyethylene terephthalate (PET), or similar polar semi -crystalline polymer. The use of a polar semi-crystalline polymer for the release liner 525 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 brought into contact with components of the dressing 110, or when subj ected to temperature or environmental variations, or sterilization. Further, a release agent may be disposed on a side of the release liner 525 that is configured to contact the third layer 505. For example, the release agent may be a silicone coating and may have a release factor suitable to facilitate removal of the release liner 525 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 525 may be uncoated or otherwise used without a release agent.

[0094] Additionally, the third layer 505 may have a third separation line 530, which may extend from a first edge of the third layer 505 to a second edge of the third layer 505. In some embodiments, the third separation line 530 may comprise a plurality of separation segments 535. Each of the separation segments 535 may comprise or consist essentially of a perforation, fenestration, indentation or other means for locally decreasing the tear strength of the third layer 505 along the third separation line 530. For example, the third separation line 530 of Figure 5 may comprise collinear slits or slots so that the third separation line 530 forms a straight line across the third layer 505.

[0095] The separation segments 535 may be arranged in a pattern that is geometrically similar to the pattern of the separation segments 225 and the separation segments 235 in some embodiments. For example, the separation segments 225 and the separation segments 535 may both be arranged so that the first separation line 220 and the third separation line 530 form parallel lines. The third separation line 530 may be substantially aligned with the first separation line 220 in some examples.

[0096] Figure 6 is a schematic view of an example configuration of the apertures 520, illustrating additional details that may be associated with some embodiments of the third layer 505. In some embodiments, the apertures 520 illustrated in Figure 6 may be associated only with an interior portion of the third layer 505. In the example of Figure 6, the apertures 520 are generally circular and have a width W, which may be about 2 millimeters in some examples. Figure 6 also illustrates an example of a uniform distribution pattern of the apertures 520. In Figure 6, the apertures 520 are distributed across the third layer 505 in a grid of parallel rows and columns. Within each row and column, the apertures 520 may be equidistant from each other, as illustrated in the example of Figure 6. The rows may be spaced a distance D4, and the apertures 520 within each of the rows may be spaced a distance D5. For example, a distance D4 of about 3 millimeters on center and a distance D5 of about 3 millimeters on center may be suitable for some embodiments. The apertures 520 in adjacent rows may be aligned or offset. For example, adjacent rows may be offset, as illustrated in Figure 6, so that the apertures are aligned in alternating rows and separated by a distance D6. A distance D6 of about 6 millimeters may be suitable for some examples. The spacing of the apertures 520 may vary in some embodiments to increase the density of the apertures 520 according to therapeutic requirements.

[0097] Figure 6 also illustrates an example configuration of the third separation line 530. In the example of Figure 6, the separation segments 535 are generally straight and may be arranged in a collinear pattern parallel to the rows of the apertures 520. One or more of the separation segments 535 may have a length L3, which may be substantially larger than the width W so that the tear strength of the third layer 505 is less along the third separation line 530 than along the rows of the apertures 520. In some examples, the length L3 may be substantially equal to the length L2 (Figure 3) of the separation segments 225.

[0098] Figure 7 is a schematic view of the third layer 505 of Figure 6 overlaid on the first layer 205 of Figure 3, illustrating additional details that may be associated with some example embodiments of the tissue interface 120. For example, as illustrated in Figure 7, the passages 215 may be aligned, overlapping, in registration with, or otherwise fluidly coupled to the apertures 520 in some embodiments. In some embodiments, one or more of the passages 215 may be registered with the apertures 520 only in an interior portion, or only partially registered with the apertures 520. The passages 215 in the example of Figure 7 are generally configured so that each of the passages 215 is registered with only one of the apertures 520. In other examples, one or more of the passages 215 may be registered with more than one of the apertures 520. For example, any one or more of the passages 215 may extend across two or more of the apertures 520. Additionally or alternatively, one or more of the passages 215 may not be registered with any of the apertures 520. [0099] As illustrated in the example of Figure 7, the apertures 520 may be sized to expose a portion of the first layer 205, the passages 215, or both through the third layer 505. In some embodiments, one or more of the apertures 520 may be sized to expose more than one of the passages 215. For example, some or all of the apertures 520 may be sized to expose two or three of the passages 215. In some examples, the length LI of each of the passages 215 may be substantially equal to the width W of each of the apertures 520. In some embodiments, the dimensions of the passages 215 may exceed the dimensions of the apertures 520, and the size of the apertures 520 may limit the effective size of the passages 215 exposed through the third layer 505.

[00100] Figure 7 further illustrates the alignment of the third separation line 530 relative to other features. For example, the third separation line 530 may be substantially aligned with the first separation line 220 (not visible in Figure 7), and may be parallel to the passages 215.

[00101] Figure 8 is an assembly view of another example of the tissue interface 120, illustrating additional details that may be associated with some example embodiments of the therapy system of Figure 1. In the example of Figure 8, the tissue interface 120 comprises a tie layer 805 in addition to the first layer 205 and the second layer 210. The tie layer 805 may have perforations 810 and may have a thickness between 10 microns and 100 microns in some embodiments. The tie layer 805 may be clear, colored, or printed. As illustrated in Figure 8, the tie layer 805 may be disposed between the first layer 205 and the second layer 210. The tie layer 805 may also be bonded to at least one of the first layer 205 and the second layer 210 in some embodiments.

[00102] The tie layer 805 may comprise polyurethane film, for example, which can be bonded to the first layer 205 and the second layer 210. For example, if the first layer 205 is formed of a polyethylene film and the second layer 210 is polyurethane foam, the first layer 205 may be more readily bonded to the tie layer 805 than directly to the second layer 210.

[00103] In Figure 8, the tie layer 805 comprises a fourth separation line 815, which may extend from a first edge of the tie layer 805 to a second edge of the tie layer 805. In some embodiments, the fourth separation line 815 may comprise a plurality of separation segments 820. Each of the separation segments 820 may comprise or consist essentially of a perforation, fenestration, indentation or other means for locally decreasing the tear strength of the tie layer 805 along the fourth separation line 815. For example, the fourth separation line 815 of Figure 8 may comprise collinear slits or slots so that the fourth separation line 815 forms a straight line across the tie layer 805.

[00104] The separation segments 820 may be arranged in a pattern that is geometrically similar to the pattern of the separation segments 225 and the separation segments 235 in some embodiments. For example, the separation segments 225 and the separation segments 820 may both be arranged so that the first separation line 220 and the fourth separation line 815 form parallel lines. The fourth separation line 815 may be substantially aligned with the first separation line 220 in some examples.

[00105] Figure 9 is a top view of another example of the tissue interface 120 having a plurality of singulation borders. In the example of Figure 9, the singulation borders comprise a plurality of the separation segments 235, which form a plurality of separation rings 905. The separation rings 905 may be substantially concentric and equidistant. The shape of the separation rings 905 may be geometrically similar to the shape of the second layer 210 in some examples. In Figure 9, for example, the second layer 210 and the separation rings 905 each have a stadium profde. Other patterns and shapes may be suitable for some embodiments, such as concentric circles, ellipses, or polygons. In some examples, the shape of the separation rings 905 may be different than the shape of the second layer 210.

[00106] As in other examples, Figure 9 also illustrates an example of the margin 410 of the first layer 205 around the second layer 210.

[00107] Figure 10 is a section view of the tissue interface 120 of Figure 9. In Figure 10, the first layer 205 comprises separation rings 1005. As in other examples, the number of singulation borders in the first layer 205 is the same as the number of singulation borders in the second layer 210. As illustrated in Figure 10, the separation rings 1005 may be generally parallel to or concentric with the separation rings 905 in the second layer 210. As illustrated in the example of Figure 10, the separation rings 1005 may be offset from the separation rings 905 by the distance d. For illustration purposes only, the passages 215 in the first layer 205 are omitted from the example of Figure 10.

[00108] Figure 11 is a top view of another embodiment of the tissue interface 120 illustrating another example configuration of a singulation border. In the example of Figure 9, the separation segments 235 are arranged in a spiral pattern. As in other examples, the margin 410 may extend past the edge of the second layer 210.

[00109] Other example patterns of singulation may be associated with some embodiments of the tissue interface 120. For example, suitable patterns may include rectangles, triangles, or other polygon patterns, which may be arranged in uniform or tessellate patterns in some embodiments. The sizes of the singulation sections may be uniform or may vary over the area of the tissue interface 120. For example, singulation sections may be larger in a core or center portion of the tissue interface 120 and may be smaller around a periphery of the tissue interface 120.

[00110] In some embodiments, one or more of the distribution components may additionally be treated with an antimicrobial agent. For example, the second layer 210 may be a foam, mesh, or non-woven coated with an antimicrobial agent. In some embodiments, the second layer 210 may comprise antimicrobial elements, such as fibers coated with an antimicrobial agent. Additionally or alternatively, some embodiments of the first layer 205 may be a polymer coated or mixed with an antimicrobial agent. Suitable antimicrobial agents may include, for example, metallic silver, PHMB, iodine or its complexes and mixes such as povidone iodine, copper metal compounds, chlorhexidine, or some combination of these materials.

[00111] Additionally or alternatively, one or more of the components may be coated with a mixture that may include citric acid and collagen, which can reduce bio-films and infections. For example, the second layer 210 may be foam coated with such a mixture. [00112] The cover 125 and the tissue interface 120 may be assembled before application or in situ. For example, the first layer 205 may be laminated to the second layer 210 in some examples. The third layer 505 may also be coupled to the first layer 205 opposite the second layer 210 in some embodiments. The geometry and dimensions of the tissue interface 120, the cover 125, or both may vary to suit a particular application or anatomy. For example, the tissue interface 120 may be sized for a specific region or anatomical area, such as for amputations. In some embodiments, the tissue interface 120 may be tom without losing pieces of the tissue interface 120 and without separation of the first layer 205 from the second layer 210.

[00113] Figure 12 is a partial side view of another example of the tissue interface 120, illustrating one method of sizing the tissue interface. As illustrated in Figure 12, the tissue interface 120 may be separated along singulation borders of the first layer 205 and the second layer 210. The first layer 205 of Figure 12 has a first singulation border 1205, and the second layer 210 has a second singulation border 1210. The first singulation border 1205 is offset from the second singulation border 1210 and closer to the edge 405 than the second singulation border 1210. In Figure 12, an adhesive 1215 is disposed between the first layer 205 and the second layer 210. In some embodiments, the adhesive 1215 may be pattern-coated on the first layer 205 or the second layer 210 so that there is no adhesive in an offset margin 1220 between the first singulation border 1205 and the second singulation border 1210.

[00114] As illustrated in the example of Figure 12, tissue interface 120 may be separated into singulation sections, such as a first section 1225 and a second section 1230, by simultaneously tearing the first layer 205 and the second layer 210 along the first singulation border 1205 and the second singulation border 1210. In general, the tissue interface 120 may be configured so that the first layer 205 and the second layer 210 may be tom by hand. For example, the force required to separate the tissue interface 120 along the singulation borders may be 10 newtons or less in some embodiments. After separation, the first section 1225 retains the offset margin 1220, which extends past the second singulation border 1210. In some examples, the cover 125 (not shown in Figure 12) may also be laminated to the second layer 210 and may have singulation borders similar to either the first layer 205 or the second layer 210, which can allow the cover 125 to be sized with the tissue interface 120.

[00115] In some examples, the first singulation border 1205 may be formed by cutting through the first layer 205, leaving bridges between the cuts. The bridges may be substantially larger than the cuts in some embodiments, which can increase stmctural integrity of the first layer 205 and reduce exposure of the second layer 210 through the singulation border 1205. The cuts may be partial cuts in some embodiments. For example, the cut may only penetrate about 80% of the first layer 205 in some embodiments, which can also reduce exposure of the second layer 210 through the singulation border 1205. Additionally, or alternatively, the tissue interface 120 may comprise an intermediate layer (not shown) disposed between the singulation border 1205 and the second layer 210. For example, a strip, ring, or other suitable configuration of polyurethane film may be aligned with the first singulation border 1205, which can insulate the second layer 210 from the first singulation border 1205.

[00116] Figure 13 is a schematic diagram of an example of the therapy system 100 applied to a tissue site 1305, further illustrating application of the tissue interface 120. In the example of Figure 13, the tissue site 1305 comprises a surface wound. In use, a release liner (if included) may be removed to expose the tissue interface 120. The tissue interface 120 may be sized to the tissue site 1305. For example, the first section 1225 of Figure 12 may be separated from the second section 1230 (not shown in Figure 13). The second section 1230 may be discarded, and the first section 1225 can be placed within, over, on, or otherwise proximate to the tissue site 1305.

[00117] In the example of Figure 13, the first layer 205 may be a contact layer, forming an outer surface of the dressing 110 that can be placed over the tissue site 1305, including an edge 1310 and epidermis 1315. The first layer 205 may be interposed between the second layer 210 and the tissue site 1305, which can prevent direct contact between the second layer 210 and epidermis 1315. Additionally, after sizing the tissue interface 120, the offset margin 1220 of the first section 1225 extends past the second layer 210, so that the second layer 210 is recessed with respect to the first layer 205, which can further protect the epidermis 1315 from direct contact with the second layer 210. In other examples, the third layer 505 (not shown in Figure 13) may form an outer surface of the dressing 110 and can provide temporary fixation over the tissue site 1305.

[00118] As illustrated in the example of Figure 13, in some applications a filler 1320 may also be disposed between the tissue site 1305 and the first layer 205. For example, if the tissue site 1305 is a surface wound, the filler 1320 may be applied interior to the edge 1310, and the first layer 205 may be disposed over the filler 1320. In some embodiments, the filler 1320 may be a manifold, such as open-cell foam. The filler 1320 may comprise or consist essentially of the same material as the second layer 210 in some embodiments.

[00119] In the example of Figure 13, the cover 125 is sized similar to the tissue interface 120 and disposed over the tissue interface 120, and the dressing 110 may include one or more attachment devices 1325. In some embodiments, one or more of the attachment devices 1325 may comprise or consist essentially of a polymer strip, such as a polyurethane strip, having an adhesive 1330 thereon. In some examples the adhesive 1330 may be, for example, a medically-acceptable, pressure-sensitive adhesive that extends about a periphery, a portion, or an entire surface of each of the attachment devices 1325. In some embodiments, for example, the adhesive 1330 may be an acrylic adhesive having a coating weight between 25-65 grams per square meter (g.s.m.). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. In some embodiments, such a layer of the adhesive 1330 may be continuous or discontinuous. Discontinuities in the adhesive 1330 may be provided by apertures or holes (not shown) in the adhesive 1330. The apertures or holes in the adhesive 1330 may be formed after application of the adhesive 1330 or by coating the adhesive 1330 in patterns on a carrier layer, such as, for example, a side of the attachment devices 1325. Apertures or holes in the adhesive 1330 may also be sized to enhance the MVTR of the attachment devices 1325 in some example embodiments. In some embodiments, one or more of the attachment devices 1325 may comprise or consist essentially of a composite strip of a perforated gel, substantially similar to the third layer 505, and a backing with an adhesive.

[00120] The attachment devices 1325 can be disposed around edges of the cover 125, and the adhesive 1330 may pressed onto the cover 125 and epidermis 1315 (or other attachment surface) to fix the dressing 110 in position and to seal the edge 405 of the second layer 210.

[00121] Figure 13 also illustrates one example of a fluid conductor 1335 and a dressing interface 1340. As shown in the example of Figure 13, the fluid conductor 1335 may be a flexible tube, which can be fluidly coupled on one end to the dressing interface 1340. The dressing interface 1340 may be an elbow connector, as shown in the example of Figure 13. In some examples, the tissue interface 120 can be applied to the tissue site 1305 before the cover 125 is applied over the tissue interface 120. The cover 125 may include an aperture 1345, or the aperture 1345 may be cut into the cover 125 before or after positioning the cover 125 over the tissue interface 120. The dressing interface 1340 can be placed over the aperture 1345 to provide a fluid path between the fluid conductor 1335 and the tissue interface 120. In other examples, the fluid conductor 1335 may be inserted directly through the cover 125 into the tissue interface 120.

[00122] If not already configured, the dressing interface 1340 may be disposed over the aperture 1345 and attached to the cover 125. The fluid conductor 1335 may be fluidly coupled to the dressing interface 1340 and to the negative-pressure source 105.

[00123] Negative pressure from the negative-pressure source 105 can be distributed through the fluid conductor 1335 and the dressing interface 1340 to the tissue interface 120. Negative pressure applied through the tissue interface 120 can also create a negative pressure differential across the passages 215 in the first layer 205, which can open or expand the passages 215. For example, in some embodiments in which the passages 215 may comprise substantially closed fenestrations through the first layer 205, a pressure gradient across the fenestrations can strain the adjacent material of the first layer 205 and increase the dimensions of the fenestrations to allow liquid movement through them, similar to the operation of a duckbill valve. Opening the perforations can allow exudate and other liquid movement through the perforations into the second layer 210. The size of the passages 215 in Figure 13 relative to other features, including the first layer 205, are exaggerated for purposes of illustration. The second layer 210 can provide passage of negative pressure and exudate, which can be collected in the container 115.

[00124] Changes in pressure can also cause the second layer 210 to expand and contract. The first layer 205 can protect the epidermis 1315 from irritation that could be caused by expansion, contraction, or other movement of the second layer 210. The first layer 205 can also substantially reduce or prevent exposure of the tissue site 1305 to the second layer 210, which can inhibit growth of tissue into the second layer 210. [00125] If the negative-pressure source 105 is removed or turned off, the pressure differential across the passages 215 can dissipate, allowing the passages 215 to close and prevent exudate or other liquid from returning to the tissue site 1305 through the first layer 205.

[00126] Additionally, or alternatively, instillation solution or other fluid may be distributed to the dressing 110, which can increase the pressure in the tissue interface 120. The increased pressure in the tissue interface 120 can create a positive pressure differential across the passages 215 in the first layer 205, which can open the passages 215 to allow the instillation solution or other fluid to be distributed to the tissue site 1305.

[00127] The systems, apparatuses, and methods described herein may provide significant advantages over prior dressings. For example, some dressings for negative-pressure therapy can require time and skill to be properly sized and applied to achieve a good fit and seal. In contrast, some embodiments of the dressing 110 can be simple to apply, reducing the time to apply and remove. In some embodiments, for example, the dressing 110 may be a fully-integrated negative-pressure therapy dressing that can be applied to a tissue site (including on the periwound) in one step, without being cut to size, while still providing or improving many benefits of other negative-pressure therapy dressings that require sizing. Some embodiments of the dressing 110 may alternatively be cut to size and readily sealed to a tissue site while still providing such benefits. Such benefits may include good manifolding, beneficial granulation, protection of the peripheral tissue from maceration, protection of the tissue site from shedding materials, and a low-trauma and high-seal bond. These characteristics may be particularly advantageous for surface wounds having moderate depth and medium-to-high levels of exudate. Some embodiments of the dressing 110 may remain on the tissue site for at least 5 days, and some embodiments may remain for at least 7 days. Antimicrobial agents in the dressing 110 may extend the usable life of the dressing 110 by reducing or eliminating infection risks that may be associated with extended use, particularly use with infected or highly exuding wounds.

[00128] 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 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, or both may be 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.

[00129] The appended claims set forth novel and inventive aspects of the subject matter described above, but the claims may also encompass additional subject matter not specifically recited in detail. For example, certain features, elements, or aspects may be omitted from the claims if not necessary to distinguish the novel and inventive features from what is already known to a person having ordinary skill in the art. Features, elements, and aspects described 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. A dressing for treating a tissue site, the dressing comprising: a first layer comprising a polymer film having a first singulation border; and a second layer comprising a manifold having an edge and a second singulation border, the second singulation border being offset from the first singulation border such that the first singulation border is closer to the edge of the manifold than the second singulation border.

2. The dressing of claim 1, the dressing further comprising a polymer drape.

3. The dressing of claim 1, wherein the polymer film comprises polyurethane.

4. The dressing of claim 1, wherein the polymer film comprises polyethylene.

5. The dressing of claim 1, wherein the manifold comprises a polymer foam.

6. The dressing of claim 1, wherein the manifold comprises a polyurethane ether foam.

7. The dressing of claim 1, wherein the manifold comprises a reticulated polymer foam.

8. The dressing of claim 1, wherein the manifold comprises a reticulated foam having a free volume of at least 90%.

9. The dressing of claim 1, wherein the manifold comprises a porous foam having an average pore size in a range of about 400 microns to about 600 microns.

10. The dressing of claim 1, wherein the manifold comprises a hydrophobic foam.

11. The dressing of claim 1, wherein the polymer film is hydrophobic.

12. The dressing of claim 1, wherein the first singulation border and the second singulation border are configured to allow first portions of the polymer film and the manifold to be separated from second portions of the polymer film and the manifold.

13. The dressing of claim 1 , wherein the polymer film forms a margin around the edge of the manifold.

14. The dressing of claim 13, wherein the margin is about 2-3mm.

15. The dressing of any preceding claim, wherein the first singulation border and the second singulation border are parallel.

16. The dressing of any preceding claim, wherein: the first singulation border comprises a plurality of first separation segments arranged in a first pattern; the second singulation border comprises a plurality of second separation segments arranged in a second pattern; and the second pattern is geometrically similar to the first pattern.

17. The dressing of claim 1, wherein the first singulation border comprises kiss-cut perforations.

18. The dressing of claim 1, wherein the first singulation border comprises partial perforations.

19. The dressing of claim 1, wherein the second singulation border comprises partial perforations.

20. The dressing of claim 1, wherein the polymer film is adhered to the manifold.

21. The dressing of claim 1, wherein the polymer film is adhered to the manifold using an acrylic adhesive.

22. The dressing of claim 1, wherein the polymer film is adhered to the manifold using a polyurethane gel adhesive.

23. The dressing of any of claims 20-22, wherein the polymer film is not adhered to the manifold in an area between the first singulation border and the second singulation border.

24. The dressing of claim 23 wherein the first singulation border and the second singulation border are separated by a distance of about 2-3mm.

25. The dressing of any preceding claim, further comprising a fluid port coupled to the polymer drape, the fluid port configured to be coupled to a fluid conductor.

26. A system for treating a tissue site, the system comprising: the dressing of any of claims 1-25; and a negative -pressure source adapted to be fluidly coupled to the dressing.

27. The system of claim 26, further comprising a fluid container adapted to be fluidly coupled between the dressing and the negative-pressure source.

28. A tissue interface for treating a tissue site with negative pressure, the tissue interface comprising: a contact layer having a first singulation border; a manifold laminated to the contact layer, the manifold having an edge and a second singulation border; and wherein the first singulation border is closer to the edge than the second singulation border.

29. The tissue interface of claim 28, wherein the first singulation border and the second singulation border are arranged in patterns having similar shapes.

30. The tissue interface of claim 28, wherein the first singulation border and the second singulation border are arranged in patterns having similar shapes that are not congruent.

31. The tissue interface of claim 28, wherein the first singulation border and the second singulation border are arranged in patterns having similar shapes that are offset by a distance in a range of about 2-3mm.

32. The tissue interface of claim 28, wherein: the manifold has a thickness; and the first singulation border and the second singulation border are arranged in patterns having similar shapes that are offset by a distance of about 50% of the thickness.

33. The tissue interface of claim 28, wherein the first singulation border and the second singulation border are arranged in parallel lines.

34. The tissue interface of any of claims 28-33, wherein the first singulation border comprises a plurality of partial perforations in the contact layer.

35. The tissue interface of any of claims 28-33, wherein the first singulation border comprises a plurality of perforations through the contact layer.

36. The tissue interface of any of claims 28-35, wherein the second singulation border comprises a plurality of perforations through the manifold.

37. The tissue interface of any of claims 28-35, wherein the second singulation border comprises a plurality of separation segments in the manifold.

38. The tissue interface of any of claims 28-37, wherein the manifold comprises foam having open cells.

39. The tissue interface of any of claims 28-38, wherein the manifold comprises a hydrophobic foam.

40. The tissue interface of any of claims 28-39, wherein the contact layer comprises polyurethane.

41. The tissue interface of any of claims 28-39, wherein the contact layer comprises polyethylene.

42. The tissue interface of any of claims 28-39, wherein the contact layer is hydrophobic.

43. A system for treating a tissue site, the system comprising: the tissue interface of any of claims 28-42; and a negative -pressure source adapted to be fluidly coupled to the tissue interface.

44. The system of claim 43, further comprising a fluid container adapted to be fluidly coupled between the tissue interface and the negative-pressure source.

45. A method of treating a tissue site, the method comprising: providing a tissue interface, the tissue interface comprising a fdm layer having a first singulation border and a manifold having a second singulation border; sizing the tissue interface along the first singulation border and the second singulation border so that the film layer forms a margin around an edge of the manifold; applying the tissue interface to the tissue site so that the film layer contacts the tissue site; placing a drape adjacent to the manifold; sealing the drape to an attachment surface around the tissue site; fluidly coupling a fluid conductor to the tissue interface through the drape; fluidly coupling the fluid conductor to a negative-pressure source; and applying negative pressure from the negative-pressure source to the manifold through the fluid conductor.

46. The method of claim 45, wherein the first singulation border is closer to the edge of the manifold than the second singulation border.

47. The method of claim 45, wherein the margin is about 2-3mm.

48. The method of claim 45, wherein the first singulation border comprises first separation segments disposed in a first pattern and the second singulation border comprises second separation segments disposed in a second pattern that is similar to the first pattern.

49. The method of claim 45, wherein sizing the tissue interface comprises applying a force to an edge of the tissue interface to detach first portion of the tissue interface from a second portion of the tissue interface.

50. The method of claim 49, wherein the force required to detach the first portion from the second portion is about 10 newtons.

51. A method of manufacturing a dressing for a tissue site, the method comprising: providing a polymer film having a first side and a second side; forming a plurality of first perforations in the polymer film in a first pattern; providing a manifold having a first side and a second side; forming a plurality of second perforations in the manifold in a second pattern offset from the first pattern; and placing the second side of the manifold adjacent to the first side of the polymer film.

52. The method of claim 51, wherein forming the first perforations in the polymer film comprises cutting through the polymer film from the first side to the second side in the first pattern, leaving bridges in the first pattern that are not cut.

53. The method of claim 51, wherein forming the first plurality of perforations in the polymer film comprises cutting the polymer film in the first pattern starting from the first side and extending about 80% through the polymer film to the second side.

54. The method of claim 51, wherein forming the second perforations in the manifold comprises cutting through the manifold from the first side to the second side in the second pattern, leaving bridges in the second pattern that are not cut.

55. The method of claim 51 , wherein forming the second perforations in the manifold comprises cutting the manifold in the second pattern starting from the first side and extending about 80% through the manifold to the second side.

56. The systems, apparatuses, and methods substantially as described herein.