Patent Description:
A sprain is an injury resulting from the wrenching or twisting of a ligament or muscle of a joint, such as a knee or ankle, characterized by clinical symptoms including swelling, bruising or contusions, pain, and disablement of the joint. A sprain may further be characterized by edema which is an abnormal accumulation of fluid in cells, tissues, or cavities of the body resulting in swelling. Strains are sprains caused by exertion or an acute trauma event. These trauma events can include, for example, an abnormal muscle contraction, a high amount of specifically applied tension, or forced stretching of the muscle of the ligament. These injuries can be extremely debilitating, especially to professional and amateur athletes who can no longer participate in physical activities. In addition, the affected area, most commonly extremities such as the foot, ankle and knee, suffer from reduced range of motion.

Acute inflammation is a response to any type of trauma including trauma events causing a sprain or strain wherein the inflammation protects the tissue and removes any damaged material or tissue from the body. Enzymatic signaling agents including histamine, serotonin, bradykinin, and prostaglandin are normally released as part of the inflammatory process. These agents increase capillary membrane permeability in order to enhance the inflammatory process, but also result in edema from fluid accumulation during the interstitial phase. The signaling agents, therefore, cause the primary symptoms of inflammation: swelling, heat, redness and pain. This initial phase of inflammation can start after one or two days and end after three or four days. In some cases, the damage to the ligament can be even more severe. For example, high ankle sprains involve injury to the ligament above the ankle that joins together the tibia and fibula, or syndesmotic ligament. Regardless of the type of strain or sprain, a single injury has been shown to place the affected extremity at significantly greater risk of re-injury even after the first injury has healed. <CIT> discloses systems and methods for applying negative pressure to a tissue site, including a dressing with a manifold and a polymer film contact layer, featuring fluid restrictions that respond to pressure gradients. <CIT> discloses a belt designed for BFR systems, featuring an inflatable chamber within hermetically sealed materials, a gas input port, fastening mechanisms for secure fit, and a pre-tensioning system for initial compression. <CIT> discloses a compression dressing for lymphoedema treatment, allowing self-application by patients. It features an elastically stretchable material with a loop pile structure, a separable slide fastener, and fabric tabs for secure attachment.

The invention is defined by the independent claim. A selection of optional features of the invention is set out in the dependent claims.

Insofar as the term embodiment is used in the following, or features are presented as being optional, this should be interpreted in such a way that the only protection sought is that of the invention claimed (with due regard to Article <NUM> EPC and the protocol thereto). References to "embodiment(s)" throughout the description which are not under the scope of the appended claims merely represent possible exemplary executions and are not part of the present invention.

<FIG> is an isometric view of an example embodiment of a dressing <NUM> that can provide therapy to a tissue site in accordance with this specification. The term "tissue site" in this context broadly refers to a wound, defect, or other treatment target located on or within tissue, including, but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. A wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial-thickness burns, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term "tissue site" may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. The dressing <NUM> described herein may be used to treat tissue sites that have intact skin or epidermis but include sprains and strains to subcutaneous tissue such as, for example, a ligament or a muscle.

As shown in <FIG>, the dressing <NUM> may include a first layer, such as a biasing or spring element <NUM>, a second layer, such as a conformable layer <NUM>, and a third layer, such as an adhesive layer <NUM>. The biasing element <NUM>, the conformable layer <NUM>, and the adhesive layer <NUM> may be configured to at least partially encircle a tissue site. The biasing element <NUM> may have an unloaded state and a loaded state, and may be deflected from the unloaded state to the loaded stated. The dressing <NUM> may be coupled to a tissue site and may be configured to exert radial expansion forces on the tissue site.

The conformable layer <NUM> may be coupled to the biasing element <NUM> and the adhesive layer <NUM> may be coupled to the conformable layer <NUM> opposite the biasing element <NUM>. In some embodiments, the edges of one or more of the biasing element <NUM>, the conformable layer <NUM>, and the adhesive layer <NUM> may be congruent, so that adjacent faces of the biasing element <NUM>, the conformable layer <NUM>, and the adhesive layer <NUM> are substantially coextensive and have substantially the same surface area. If the dressing <NUM> is applied to the tissue site, the conformable layer <NUM> may be between the tissue site and the biasing element <NUM>.

The biasing element <NUM> may have a first side <NUM> and a second, patient-facing side <NUM>. The conformable layer <NUM> may have a first side <NUM> and a second, patient-facing side <NUM>. The adhesive layer <NUM> may have a first side <NUM> and a second, patient-facing side <NUM>. The first side <NUM> of the conformable layer <NUM> may be coupled to the second, patient-facing side <NUM> of the biasing element <NUM>. The first side <NUM> of the adhesive layer <NUM> may be coupled to the second, patient-facing side <NUM> of the conformable layer <NUM>.

In some embodiments, the biasing element <NUM> may define the shape of the other components of the dressing <NUM>, such as the conformable layer <NUM> and the adhesive layer <NUM>, as well as the dressing <NUM> as a whole. In some embodiments, the biasing element <NUM> may include or be formed of a curved wall <NUM> forming a tubular shape. The biasing element <NUM> may further include a first open end <NUM>, a second open end <NUM>, and an opening <NUM> in the curved wall <NUM> extending from the first open end <NUM> to the second open end <NUM>. The opening <NUM> may define a first edge <NUM> and a second edge <NUM>. The dressing <NUM> may be sized such that, when the biasing element <NUM> is in the unloaded state, the anatomy proximate to the tissue site can be inserted into one of the first open end <NUM> or the second open end <NUM>. For example, if the tissue site is located at or proximate to a wrist of a patient, the dressing <NUM> may be sized so that the dressing <NUM> can be slipped over the wrist. In some embodiments, when the dressing <NUM> is in the unloaded state, the dressing <NUM> may have a shape similar to the anatomy to which it is configured to be coupled to in its loaded state. For example, the dressing <NUM> may have a three-dimensional anatomical shape similar to a knee, ankle, foot, or wrist in its unloaded state. In some embodiments, the dressing <NUM> may be packaged, shipped, and/or sold having a three-dimensional anatomical shape in its unloaded state.

Compression of the biasing element <NUM>, for example in the direction of arrows <NUM>, from the unloaded state to the loaded state may bring the first edge <NUM> closer to the second edge <NUM>. The biasing element <NUM> may be biased toward the unloaded state. Thus, when deflected to the loaded state, the biasing element <NUM> will want to return to the unloaded state. For example, when compressed, the biasing element <NUM> will want to move the first edge <NUM> and the second edge <NUM> away from one another.

In some embodiments, the biasing element <NUM> may include or be formed of a material that can be deflected from an unloaded state to a loaded state. For example, the biasing element <NUM> may be formed from one or more of the following materials: plastics, such as polypropylene (PP), acrylonitrile butadiene styrene (ABS), and polyvinyl chloride (PVC); metals, such as steel or alloys thereof; and/or composite materials. The biasing element <NUM> may have a thickness in a range of about <NUM> millimeter to about <NUM> millimeters. In some embodiments, the biasing element <NUM> may have a thickness less than <NUM> millimeter. In some embodiments, the biasing element <NUM> may have a thickness greater than <NUM> millimeters. In some embodiments, the thickness of the biasing element <NUM> may be constant across the biasing element <NUM>. In some embodiments, the thickness of the biasing element <NUM> may vary across the biasing element <NUM>.

As further shown in <FIG>, the biasing element <NUM> may include one or more apertures <NUM>. The apertures <NUM> may be formed by cutting, perforating, punching, or by other suitable techniques for forming an aperture, opening, perforation, or hole in the biasing element <NUM>, including but not limited to using a single- or multiple-blade cutter, a laser, a water jet, a hot knife, a computer numeric control (CNC) cutter, a hot wire, local RF or ultrasonic energy, and/or a single- or multiple-punch tool. In some embodiments, the apertures <NUM> may be molded into the biasing element <NUM>, for example, in an injection molding process. The apertures <NUM> extend from the first side <NUM> to the second, patient-facing side <NUM> of the biasing element <NUM>, creating a through hole or passage in the biasing element <NUM>. The apertures <NUM> in the biasing element <NUM> may have many shapes, for example, including but not limited to circles, squares, stars, ovals, hexagons, polygons, slits, complex curves, rectilinear shapes, triangles or may have some combination of such shapes.

Each of the apertures <NUM> may have uniform or similar geometric properties. For example, in some embodiments, each of the apertures <NUM> may be circular apertures, having substantially the same diameter. In some embodiments, each of the apertures <NUM> may have a diameter in a range of about <NUM> millimeter to about <NUM> millimeters. In other embodiments, each of the apertures <NUM> may have a diameter in a range of about <NUM> millimeter to about <NUM> millimeters. In other embodiments, each of the apertures <NUM> may have a diameter in a range of about <NUM> millimeter to about <NUM> millimeters. In yet other embodiments, each of the apertures <NUM> may have a diameter in a range of about <NUM> millimeters to about <NUM> millimeters.

The conformable layer <NUM> may be a material configured to conform to the shape of the tissue site. The conformable layer <NUM> may increase the comfort of the dressing <NUM>. In some embodiments, the conformable layer <NUM> may be vapor permeable. In some embodiments, the conformable layer <NUM> may be a manifold, which may include a plurality of pathways, which can be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, a manifold may include or be formed of a porous material having interconnected fluid pathways. Examples of suitable porous material that can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, a manifold may additionally or alternatively include projections that form interconnected fluid pathways. For example, a manifold may be molded to provide surface projections that define interconnected fluid pathways.

In some embodiments, the conformable layer <NUM> may include or be formed of reticulated foam having pore sizes and free volume that may vary according to needs of a prescribed therapy. For example, reticulated foam having a free volume of at least <NUM>% may be suitable for many therapy applications, and foam having an average pore size in a range of <NUM>-<NUM> microns (<NUM>-<NUM> pores per inch) may be particularly suitable for some types of therapy. The tensile strength of the conformable layer <NUM> may also vary according to needs of a prescribed therapy. The <NUM>% compression load deflection of the conformable layer <NUM> may be at least <NUM> pounds per square inch, and the <NUM>% compression load deflection may be at least <NUM> pounds per square inch. In some embodiments, the tensile strength of the conformable layer <NUM> may be at least <NUM> pounds per square inch. The conformable layer <NUM> may have a tear strength of at least <NUM> pounds per inch. In some embodiments, the conformable layer <NUM> may have a tear strength of at least <NUM> N. In some embodiments, the conformable layer <NUM> may be foam formed 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 conformable layer <NUM> may be reticulated polyurethane foam such as found in GRANUFOAM™ dressing or V. VERAFLO™ dressing, both available from Kinetic Concepts, Inc.

The thickness of the conformable layer <NUM> may also vary according to needs of a prescribed therapy. The thickness of the conformable layer <NUM> can also affect the conformability of the conformable layer <NUM>. In some embodiments, a thickness in a range of about <NUM> millimeters to <NUM> millimeters may be suitable. In some embodiments, the conformable layer <NUM> may have a thickness less than <NUM> millimeters. In some embodiments, the conformable layer <NUM> may have a thickness greater than <NUM> millimeters.

The conformable layer <NUM> may be either hydrophobic or hydrophilic. In an example in which the conformable layer <NUM> may be hydrophilic, the conformable layer <NUM> may also wick fluid away from a tissue site. The wicking properties of the conformable layer <NUM> may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. The fluid drawn away may flow out of or evaporate through the apertures <NUM> of the biasing element <NUM>. An example of a hydrophilic material that may be suitable is a polyvinyl alcohol, open-cell foam such as V. WHITEFOAM™ dressing available from Kinetic Concepts, Inc. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

In some embodiments, the conformable layer <NUM> may include or be formed of a closed-cell foam. For example, the conformable layer <NUM> may be formed of silicone, polyurethane (PU), or ethylene vinyl acetate (EVA). The structure of these closed-cell foams 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. For example, the conformable layer <NUM> may be a closed-cell foam having an average pore size in a range of about <NUM> millimeters (<NUM> microns) to about <NUM> millimeter (<NUM> microns). In some embodiments, the conformable layer <NUM> may be a closed-cell foam having a porosity in a range of about <NUM> ppi to about <NUM> ppi. In some examples, the conformable layer <NUM> may be a closed-cell foam available from Zotefoams plc of Croydon, United Kingdom.

Additionally, in some embodiments, the conformable layer <NUM> may be thermally conductive. The conformable layer <NUM> may be configured to remove heat from the tissue site to reduce thermal build-up at the tissue. This may increase comfort of the dressing <NUM>. In some embodiments, the conformable layer <NUM> may be metal loaded to increase thermal conductivity.

In some embodiments, the conformable layer <NUM> may store, or immobilize, liquid from a tissue site. The conformable layer <NUM> may contain any substance capable of storing a liquid. The conformable layer <NUM> may include, without limitation, super absorbent fiber/particulates, hydrofibre, sodium carboxymethyl cellulose, and/or alginates. In some exemplary embodiments, the conformable layer <NUM> may include a superabsorbent polymer (SAP). Generally, relative to their mass, SAPs can absorb and retain large quantities of liquid, and in particular water. SAPs may be used to hold and stabilize or solidify wound fluids. SAPs may be of the type often referred to as "hydrogels," "super-absorbents," or "hydrocolloids. " In some embodiments, the conformable layer <NUM> may include SAP fibers or spheres. The SAP fibers may be either woven or non-woven. In some embodiments, the SAPs may be dispersed as pellets throughout and/or embedded as a sheet-like layer within the conformable layer <NUM>.

The SAPs may be formed in several ways, for example, by gel polymerization, solution polymerization, or suspension polymerization. Gel polymerization may involve blending of acrylic acid, water, cross-linking agents, and ultraviolet (UV) initiator chemicals. The blended mixture may be placed into a reactor where the mixture is exposed to UV light to cause crosslinking reactions that form the SAP. The mixture may be dried and shredded before subsequent packaging and/or distribution. Solution polymerization may involve a water based monomer solution that produces a mass of reactant polymerized gel. The monomer solution may undergo an exothermic reaction that drives the crosslinking of the monomers. Following the crosslinking process, the reactant polymer gel may be chopped, dried, and ground to its final granule size. Suspension polymerization may involve a water-based reactant suspended in a hydrocarbon-based solvent. However, the suspension polymerization process must be tightly controlled and is not often used.

SAPs absorb liquids by bonding with water molecules through hydrogen bonding. Hydrogen bonding involves the interaction of a polar hydrogen atom with an electronegative atom. As a result, SAPs absorb water based on the ability of the hydrogen atoms in each water molecule to bond with the hydrophilic polymers of the SAP having electronegative ionic components. High absorbing SAPs are formed from ionic crosslinked hydrophilic polymers such as acrylics and acrylamides in the form of salts or free acids. Because the SAPs are ionic, they are affected by the soluble ionic components within the solution being absorbed and will, for example, absorb less saline than pure water. The lower absorption rate of saline is caused by the sodium and chloride ions blocking some of the water absorbing sites on the SAPs. If the fluid being absorbed by the SAP is a solution containing dissolved mineral ions, fewer hydrogen atoms of the water molecules in the solution may be free to bond with the SAP. Thus, the ability of an SAP to absorb and retain a fluid may be dependent upon the ionic concentration of the fluid being absorbed. For example, an SAP may absorb and retain de-ionized water up to <NUM> times the weight of the dry SAP. In volumetric terms, an SAP may absorb fluid volumes as high as <NUM> to <NUM> times the dry volume of the SAP. Other fluids having a higher ionic concentration may be absorbed at lower quantities. For example, an SAP may only absorb and retain a solution that is <NUM>% salt (NaCl) up to <NUM> times the weight of the dry SAP.

In some embodiments, the conformable layer <NUM> may include or be formed of a KERRAMAX CARE™ Super-Absorbent Dressing material available from Kinetic Concepts, Inc. For example, the conformable layer <NUM> may include or be formed of a superabsorbent laminate comprised of <NUM>. FAVOR-PAC™ <NUM> superabsorbent powder glued by PAFRA™ <NUM> adhesive between two layers of <NUM>. LIDRO™ non-woven material. In some embodiments, the conformable layer <NUM> may include or be formed of an absorbent available from Gelok International.

Because the dressing <NUM> may be positioned on the tissue site for a prolonged period of time, the conformable layer <NUM> may also possess an antimicrobial property to mitigate the risk of fungal infection and the spread of such infections caused by perspiration and warm temperatures in the dressing <NUM>. The antimicrobial property of the conformable layer <NUM> may reduce the effect of VOCs to reduce odors being generated by the dressing <NUM>. The antimicrobial property may be achieved by means of a silver coating that covers the conformable layer <NUM> or by a silver additive to the conformable layer <NUM>. In some embodiments, the conformable layer <NUM> may include activated charcoal to reduce or eliminate odor. For example, the conformable layer <NUM> may be loaded with activated charcoal particles throughout its thickness. In some embodiments, the conformable layer <NUM> may be coated with activated charcoal. In addition to reducing odor, the activated charcoal may also increase evaporation rates from the dressing <NUM> as fluid molecules may be drawn to the conformable layer <NUM>. In some embodiments, the conformable layer <NUM> may include or be coated with oxysalts, which can reduce bacterial colonization within the conformable layer <NUM>.

The adhesive layer <NUM> is configured to be coupled to the tissue site. The dressing <NUM> thus may be coupled to the tissue site by the adhesive layer <NUM>. For example, the second, patient-facing side <NUM> of the adhesive layer <NUM> is configured to contact the tissue site. The adhesive layer <NUM> may include or be formed of an adhesive. The adhesive may be coupled to the second, patient-facing side <NUM> of the conformable layer <NUM>. In some embodiments, the adhesive may be coated, printed, or deposited on the second, patient-facing side <NUM> of the conformable layer <NUM>. The adhesive may be a medically-acceptable adhesive. The adhesive may also be flowable. For example, the adhesive may be an acrylic adhesive, rubber adhesive, high-tack or tacky silicone adhesive, polyurethane, or other adhesive substance. In some embodiments, the adhesive may be a pressure-sensitive adhesive, such as an acrylic adhesive with coating weight of <NUM> grams/m<NUM> (gsm) to <NUM> grams/m<NUM> (gsm). The adhesive layer <NUM> may be capable of resisting the expansion forces of the biasing element <NUM>, such that as the biasing element <NUM> applies a pulling force on the tissue site, the adhesive layer <NUM> does not release from the tissue site. To achieve the desired bond to the tissue site, the adhesive layer <NUM> may be dependent upon the surface area of the adhesive of the adhesive layer <NUM> and the peel strength of the adhesive. Having a high surface area may be desired as a larger adhesive surface area may tend to distribute the pulling force from the biasing element <NUM> on a larger area of the tissue site, whereas a smaller adhesive surface area may result in skin tearing and or redness. In some embodiments, the adhesive may have a peel strength or resistance to being peeled from a stainless steel material in a range of about <NUM> N to about <NUM> N. In some embodiments, the adhesive may have a peel strength or resistance to being peeled from a stainless steel material of about <NUM> N. The peel strength may be measured by applying a <NUM> inch (<NUM>) wide test strip of the adhesive to a stainless steel plate using a roller. The test strip is then peeled back over itself (at an angle of <NUM> degrees) and the force required to peel the test strip is measured. The test is conducted at on a stainless steel substrate at <NUM> degrees C at <NUM> % relative humidity based on ASTM D3330.

In some embodiments, the adhesive of the adhesive layer <NUM> may be reduced or deactivated using ultraviolet light. For example, the adhesive of the adhesive layer <NUM> may be an ultraviolet switching adhesive. Ultraviolet light may be shined upon the dressing <NUM> and the ultraviolet light may reduce the peel strength of the adhesive a sufficient amount to allow removal of the dressing <NUM> from the tissue site without damage to the tissue site. Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the adhesion to the tissue site. Other example embodiments of an adhesive may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.

Individual components of the dressing <NUM> may be bonded or otherwise secured to one another with a solvent or non-solvent adhesive, or with thermal welding, for example, without adversely affecting fluid management.

<FIG> is an isometric view of another example embodiment of a dressing <NUM>. In the example embodiment of <FIG>, the dressing <NUM> is configured for delivering therapy to a tissue site <NUM>, such as, for example, proximate a knee <NUM> of a patient. The dressing <NUM> may be configured to be disposed at least partially around the tissue site <NUM>. In some embodiments, the dressing <NUM>, in its unloaded state, may be shaped in three dimensions and may have contours and/or a variable thickness to provide appropriate expansion over the tissue site <NUM>. The dressing <NUM> may have an anatomical shape in some embodiments, or may be shaped such that when wrapped around the patient it is anatomically shaped or conforms to an anatomical shape. For example, the dressing <NUM> has a shape configured to conform to at least a portion of the knee <NUM> and the leg <NUM>.

In the example shown in <FIG>, some embodiments of the biasing element <NUM> may include a first cuff <NUM>, a second cuff <NUM>, and a stem <NUM> connected to and extending between the first cuff <NUM> and the second cuff <NUM>. The conformable layer <NUM> and the adhesive layer <NUM> may be coextensive with the biasing element <NUM> or similarly shaped, such that the conformable layer <NUM> and the adhesive layer <NUM> may also include a first cuff, a second cuff, and a stem by way of analogy. Thus, the dressing <NUM>, the conformable layer <NUM>, and the adhesive layer <NUM> can each interchangeably be referred to as including the first cuff <NUM>, the second cuff <NUM>, and the stem <NUM> connected to and extending between the first cuff <NUM> and the second cuff <NUM>.

The first cuff <NUM> may be configured to extend at least partially around the back of the leg <NUM> above the knee <NUM> and the second cuff <NUM> may be configured to extend at least partially around the back of the leg <NUM> below the knee <NUM>. The stem <NUM> may be configured to cover at least a portion of the front of the knee <NUM>. Additionally, in some embodiments, the stem <NUM> does not extend around the back of the knee <NUM>, leaving the popliteal fossa region of the knee <NUM> uncovered by the dressing <NUM>. As further shown in <FIG>, in some embodiments, the some of the apertures <NUM> in the biasing element <NUM> may be located in one or more of the first cuff <NUM>, the second cuff <NUM>, and the stem <NUM>.

Although shown in the example embodiment of <FIG> as being used to treat a tissue site <NUM> proximate a knee <NUM>, some embodiments of the dressing <NUM> may be configured for treating other portions of a patient. Other exemplary embodiments of the dressing <NUM> may be suitable for the treatment of ligaments or muscles associated with other joints such as, for example, a knee, ankle, wrist, shoulder, finger, hip, or elbow joint.

<FIG> is a section view of the dressing <NUM> of <FIG> along line <NUM>-<NUM>. As shown in <FIG>, the dressing <NUM> is shown as coupled to the epidermis <NUM> of a patient proximate the tissue site <NUM> and at least partially encircling the tissue site <NUM>. The biasing element <NUM> may have an arc-shaped cross-section having a central angle Θ of at least <NUM> degrees when the biasing element <NUM> is in the unloaded state. In some embodiments, the biasing element <NUM> may have an arc-shaped cross-section having a central angle Θ of at least <NUM> degrees when the biasing element <NUM> is in the unloaded state. Because the biasing element <NUM> may define the shape of the other components of the dressing <NUM>, such as the conformable layer <NUM> and the adhesive layer <NUM>, as well as the dressing <NUM> as a whole, the conformable layer <NUM>, the adhesive layer <NUM>, and the dressing <NUM> may also have an arc-shaped cross-section having a central angle Θ of at least <NUM> degrees when the biasing element <NUM> is in the unloaded state. In some embodiments, the conformable layer <NUM>, the adhesive layer <NUM>, and the dressing <NUM> as a whole may also have an arc-shaped cross-section having a central angle Θ of at least <NUM> degrees when the biasing element <NUM> is in the unloaded state.

As further shown in <FIG>, the conformable layer <NUM> may have one or more apertures <NUM>. The apertures <NUM> may be formed by cutting, perforating, punching, or by other suitable techniques for forming an aperture, opening, perforation, or hole in the conformable layer <NUM>, including but not limited to using a single- or multiple-blade cutter, a laser, a water jet, a hot knife, a computer numeric control (CNC) cutter, a hot wire, local RF or ultrasonic energy, and/or a single- or multiple-punch tool. The apertures <NUM> extend from the first side <NUM> to the second, patient-facing side <NUM> of the conformable layer <NUM>, creating a through hole or passage in the conformable layer <NUM>. The apertures <NUM> in the conformable layer <NUM> may have many shapes, for example, including but not limited to circles, squares, stars, ovals, hexagons, polygons, slits, complex curves, rectilinear shapes, triangles or may have some combination of such shapes.

In some embodiments, the adhesive layer <NUM> may be continuous or discontinuous. Discontinuities in adhesive layer <NUM> may be provided by one or more apertures <NUM> in the adhesive layer <NUM>. The apertures <NUM> in the adhesive layer <NUM> may be formed after application of the adhesive layer <NUM> or by coating the adhesive layer <NUM> in patterns on a carrier layer, such as, for example, the second, patient-facing side <NUM> of the conformable layer <NUM>. The apertures <NUM> may be formed by cutting, perforating, punching, or by other suitable techniques for forming an aperture, opening, perforation, or hole in the adhesive layer <NUM>, including but not limited to using a single- or multiple-blade cutter, a laser, a water jet, a hot knife, a computer numeric control (CNC) cutter, a hot wire, local RF or ultrasonic energy, and/or a single- or multiple-punch tool. The apertures <NUM> extend from the first side <NUM> to the second, patient-facing side <NUM> of the adhesive layer <NUM>, creating a through hole or passage in the adhesive layer <NUM>. The apertures <NUM> in the adhesive layer <NUM> may have many shapes, for example, including but not limited to circles, squares, stars, ovals, hexagons, polygons, slits, complex curves, rectilinear shapes, triangles or may have some combination of such shapes.

As illustrated in <FIG>, the apertures <NUM> in the adhesive layer <NUM> may be aligned, overlapping, in registration with, or otherwise fluidly coupled to the apertures <NUM> in the conformable layer <NUM> and the apertures <NUM> in the biasing element <NUM> in some embodiments. Thus, at least some of the plurality of apertures <NUM> have corresponding apertures <NUM> and apertures <NUM>, wherein the corresponding apertures <NUM>, apertures <NUM>, and apertures <NUM> are in fluid communication. The corresponding apertures <NUM>, apertures <NUM>, and apertures <NUM> may cooperate to form one or more passageways <NUM> through which fluid may flow. The apertures <NUM>, apertures <NUM>, and apertures <NUM>, and the passageways <NUM> formed thereby, may enhance the MVTR of the dressing <NUM> in some example embodiments, allowing skin moisture, perspiration, or other fluids to migrate away from the patient through the dressing <NUM>.

In some embodiments, the apertures <NUM>, apertures <NUM>, and apertures <NUM>, and the passageways <NUM> formed thereby, may allow for fluids to be supplied to the tissue site <NUM>. For example, over time, the bond of the adhesive layer <NUM> to the tissue site may increase, and thus the adhesive layer <NUM> may offer higher resistance to removal. Additionally, the application of heat (such as heat from the patient) can increase the bond strength of the adhesive layer <NUM>. Accordingly, the passageways <NUM> may be configured to permit a liquid to be drawn through the passageways <NUM> such that the liquid contacts the adhesive layer <NUM>. The liquid then interacts with the adhesive layer <NUM> to reduce the peel strength of the adhesive layer <NUM>. This allows the adhesive layer <NUM> to be removed from the tissue site <NUM> without damage to the tissue site <NUM>, even if the dressing <NUM> has been adhered to the tissue site for a long period of time. In some embodiments, the liquid may be an alcohol, such as isopropyl alcohol. For example, a user may apply a small amount of isopropyl alcohol to the dressing <NUM>. The isopropyl alcohol may then be drawn through the passageways <NUM> and will soften the adhesive of the adhesive layer <NUM> over about a <NUM> to <NUM> minute period, thus reducing the peel strength of the adhesive of the adhesive layer <NUM>. The dressing <NUM> may then be removed from the tissue site <NUM>. After removal, the isopropyl alcohol will evaporate, and the peel strength of the adhesive of the adhesive layer <NUM> will return to only slightly less than its original level (about <NUM>%), allowing the dressing <NUM> to be re-adhered to the tissue site <NUM>, if desired.

In operation, the dressing <NUM> may be placed over, on, or otherwise proximate to the tissue site <NUM>. In some embodiments, the tissue site <NUM> may be inserted into the dressing <NUM>. The dressing <NUM>, including one or more of the biasing element <NUM>, the conformable layer <NUM>, and the adhesive layer <NUM> may at least partially encircle the tissue site <NUM>. Then, an external force may be placed on the biasing element <NUM> to place the biasing element <NUM> in the loaded state. For example, the dressing <NUM> may be compressed to deflect the biasing element <NUM> from the unloaded state to the loaded state. The external force placed on the biasing element <NUM> may be sufficient to couple the dressing <NUM> on, around, or otherwise proximate to the tissue site <NUM> using the adhesive layer <NUM>. For example, the dressing <NUM> may be pressed onto the epidermis <NUM> so that the adhesive layer <NUM> is sufficiently adhered to the epidermis <NUM>, such that when the external force is removed from the biasing element <NUM>, the dressing <NUM> remains coupled to the epidermis <NUM>. During application of the dressing <NUM>, the conformable layer <NUM> may conform to the shape of the tissue site <NUM> and any anatomy surrounding the tissue site <NUM> to ensure contact between the adhesive layer <NUM> and the tissue site <NUM> across some or all of the surface area of the adhesive layer <NUM>.

Because the biasing element <NUM> is configured to return to the unloaded state from the loaded state, the biasing element <NUM> exerts a pulling force on the tissue site <NUM>. In some embodiments, the adhesive layer <NUM> has a peel strength that is at least <NUM>% greater than the pulling force of the biasing element <NUM>. This reduces or prevents the adhesive layer <NUM> from becoming detached from the tissue site <NUM> and any anatomy surrounding the tissue site <NUM>.

As illustrated in the example of <FIG>, after the external force is removed from the biasing element <NUM>, the spring force in the biasing element <NUM> that urges the biasing element <NUM> from the loaded state to the unloaded state, pulls the intact skin radially outwardly as shown by arrows <NUM>. The outward force being distributed to the epidermis <NUM> by the biasing element <NUM> can promote perfusion by pulling the epidermis <NUM> outward for a sustained period of time rather than compressing the tissue site <NUM>. The pulling force exerted by the biasing element <NUM> on the tissue site <NUM> can increase blood and lymphatic flow through the tissue site <NUM>.

<FIG> is an isometric view of another example embodiment of the dressing <NUM>. <FIG> is an isometric detail view, with a portion shown in cross-section, of the dressing <NUM> of <FIG>. As shown in <FIG>, some embodiments of the dressing <NUM> may include an elongate strap <NUM>, one or more slider elements <NUM> coupled to the elongate strap <NUM>, and a winder element <NUM> coupled to the elongate strap <NUM>.

The elongate strap <NUM> may have a first end <NUM>, a second end <NUM>, and a length extending between the first end <NUM> and the second end <NUM>. In some embodiments, the elongate strap <NUM> may have a rectangular cross-section having a first side <NUM> and a second side <NUM>. The second side <NUM> may have a pattern of ratchet teeth <NUM> extending at least along a portion of the length of the elongate strap <NUM>. The elongate strap <NUM> may be formed of a strip of metal or plastic, such as nylon. The elongate strap <NUM> is similar to a cable tie or zip tie. Although the dressing <NUM> is shown as having a single elongate strap <NUM>, in some embodiments, the dressing <NUM> may include two or more elongate straps <NUM>.

The slider elements <NUM> may include a slider body <NUM> having an aperture <NUM> that is configured to receive the elongate strap <NUM>. For example, the aperture <NUM> may be sized and shaped to receive the elongate strap <NUM>. The slider elements <NUM> may be on the elongate strap <NUM> and be configured to move or slide freely along the length of the elongate strap <NUM>. The slider elements <NUM> may further include an adhesive layer <NUM> coupled to the slider body <NUM>, wherein the adhesive layer <NUM> is configured to couple the slider elements <NUM> to the tissue site <NUM>.

As shown in <FIG>, the dressing <NUM> includes four slider elements <NUM>. However, embodiments of the dressing <NUM> may include any number of slider elements <NUM>. For example, fewer than four or greater than four slider elements <NUM> may be used depending on the therapy needs, the size of the tissue site <NUM>, and/or the size of the anatomy proximate the tissue site <NUM>. For example, more slider elements <NUM> may be used if the tissue site <NUM> is proximate the knee <NUM> and fewer slider elements <NUM> may be used if the tissue site <NUM> is proximate an elbow or wrist of a patient.

The winder element <NUM> may be coupled to the second end <NUM> of the elongate strap <NUM>. For example, the winder element <NUM> may be fixed to the second end <NUM> such that there is no relative movement between the second end <NUM> and the winder element <NUM>. The winder element <NUM> may include a winder body <NUM> and a winder mechanism (not shown). The winder body <NUM> may have an aperture <NUM> that is configured to receive the elongate strap <NUM>. For example, the aperture <NUM> may be sized and shaped to receive the elongate strap <NUM>. The winder mechanism may be configured to advance or retreat the elongate strap <NUM> through the aperture <NUM>. The winder mechanism may be any suitable ratcheting device including, for example, a ratchet wheel and pawl operable on the elongate strap <NUM> to move the elongate strap <NUM> relative to the winder body <NUM>. For example, the winder mechanism may be configured to engage the ratchet teeth <NUM> on the second side <NUM> of the elongate strap <NUM>. The winder mechanism may include a toothed gear that can cooperate with the ratchet teeth <NUM>. The winder mechanism may be coupled to a key <NUM>, wherein rotation of the key <NUM> can cause rotation of the winder mechanism. The first end <NUM> of the elongate strap <NUM> is configured to be folded over and inserted into and through the aperture <NUM> of the winder body <NUM> as shown by arrow <NUM>. The elongate strap <NUM> can be advanced into the aperture <NUM> of the winder body <NUM> by pushing or pulling it through the aperture <NUM>. In some embodiments, the elongate strap <NUM> may only be retreated out of the aperture <NUM> by rotation of the key <NUM>.

<FIG> are section views of the dressing <NUM> of <FIG> coupled to the epidermis <NUM> of a patient proximate the tissue site <NUM> and encircling the tissue site <NUM>. In operation, the dressing <NUM> may be placed over, on, or otherwise proximate to the tissue site <NUM>. The elongate strap <NUM> may be wrapped circumferentially around the tissue site <NUM>. When wrapped around the tissue site <NUM>, the dressing <NUM> may form a ring around the tissue site <NUM>. The first end <NUM> of the elongate strap <NUM> may be extended through the aperture <NUM> (not shown) of the winder body <NUM>. The slider elements <NUM> may be coupled to the epidermis <NUM> proximate the tissue site <NUM> using the adhesive layers <NUM>. Any slack in the elongate strap <NUM> may be removed by advancing the first end <NUM> of the elongate strap <NUM> through the winder body <NUM> along arrow <NUM>, effectively reducing the diameter of the ring formed by the dressing <NUM> around the tissue site <NUM>. The first end <NUM> of the elongate strap <NUM> may be advanced, for example, by pulling on the elongate strap <NUM>. Following application of the dressing <NUM> on the tissue site <NUM>, the key <NUM> may be rotated, for example along arrow <NUM>, to move the first end <NUM> of the elongate strap <NUM> toward to the winder body <NUM> along arrow <NUM>. Moving the first end <NUM> of the elongate strap <NUM> increases the diameter of the ring formed by the dressing <NUM>. Because the dressing <NUM> is adhered to the tissue site <NUM> by the adhesive layers <NUM> on the slider elements <NUM>, increasing the diameter of the ring formed by the dressing <NUM> exerts a pulling force on the tissue site <NUM> as represented by arrows <NUM>.

In some embodiments, key <NUM> can be removed from the dressing <NUM> after the desired tension is applied. This may reduce or eliminate the key <NUM> from snagging on clothing, medical equipment, other persons, or other objects. In some embodiments, the winder mechanism may be configured to slip on the ratchet teeth <NUM> of the elongate strap <NUM> or disengage from the ratchet teeth <NUM> if the tension applied by the key <NUM> exceeds a certain tension level. This may provide a safety mechanism so that too high a pulling force is not applied to the tissue site <NUM>. In some embodiments, an electric motor may be coupled to the winder mechanism to move the elongate strap <NUM>. A controller may control the electric motor in response to a sensed motor current draw and/or strain on the elongate strap <NUM> to ensure that the tension does not exceed a certain tension level. In some embodiments, the controller may be on board the dressing <NUM>. In some embodiments, the electric motor may communicate with and/or controlled by a remote controller, either wired or wirelessly. The remote controller may be, for example, a smartphone.

The systems, apparatuses, and methods described herein may provide significant advantages. For example, use of the dressing <NUM> to treat wounds, strains, sprains, and other injuries to ankles and other joints can significantly reduce recovery time. The standard of care for strains and sprains for many decades has included rest, ice, compression and elevation. After a period of anywhere from <NUM> days to <NUM> weeks for minor injuries, patients commonly report a reduction in pain and return to motion. For major injuries, however, patients report a reduction in pain after one year, two years, and even more time. Even after these lengthy time periods, an equally significant number of patients still report pain and no return to motion.

Healing time for more traumatic sprains and strains with rest, ice, compression, and elevation can be much longer, typically ranging from <NUM> to <NUM> months. Even then, if the injury is still unstable after this time, surgery is often required to stabilize the joint. This prolonged healing time represents a significant loss of mobility, and delay in return to functional activity. Even for the majority of sprains and strains, the current standard of care also suffers from several practical drawbacks in addition to inadequate healing. Ice can only be applied for a limited time, as prolonged contact is either not practical because it melts or causes even more discomfort and pain because of the cold temperature being applied to the affected extremity. Compression with current devices, especially with elastic wraps, is either inadequate for applying a sufficient and consistent positive force (e.g., the wrap slips over time or is applied and re-applied incorrectly), or actually restricts blood flow and lymph flow.

The dressing <NUM> can effectively splint and stabilize a joint, such as the knee <NUM>. The dressing <NUM> can pull the tissue site <NUM> outwardly. This pulling force adjacent to the epidermis <NUM>, coupled with the immobilization of the joint, can stimulate the blood flow (perfusion) and lymphatic flow at the tissue site <NUM>, which can accelerate healing of the damaged ligament and/or muscle. Damaged tissue can be properly supplied and evacuated with blood flow and lymph flow, thereby promoting perfusion in the subcutaneous portions of the tissue site <NUM> and reducing edema to accelerate healing. In contrast, current treatments may only temporarily reduce inflammation by icing and may actually constrict blood flow and lymph flow by compression. Thus, the dressing <NUM> can provide the advantages of managing pain by reducing swelling and inflammation, increasing stability to the tissue site <NUM>, and accelerating healing by increasing blood flow and lymph flow. In testing, about <NUM>% increased average flow rates have been observed. In some testing, peak measurements of <NUM>% increased air flow have been observed. Another advantage of the dressing <NUM> is that it can provide the benefits of opening the flow channels of the tissue site without the need for a tethered negative pressure therapy system.

While shown in a few illustrative embodiments, a person having ordinary skill in the art will recognize that the systems, apparatuses, and methods described herein are susceptible to various changes and modifications that fall within the scope of the appended claims. Moreover, descriptions of various alternatives using terms such as "or" do not require mutual exclusivity unless clearly required by the context, and the indefinite articles "a" or "an" do not limit the subject to a single instance unless clearly required by the context. Components may be also be combined or eliminated in various configurations for purposes of sale, manufacture, assembly, or use.

Claim 1:
An apparatus for increasing fluid flow through a tissue site, the apparatus comprising:
a first layer (<NUM>) shaped to at least partially encircle the tissue site, the first layer (<NUM>) having an unloaded state and a loaded state;
a second layer (<NUM>) coupled to the first layer (<NUM>); and
a third layer (<NUM>) comprising an adhesive coupled to the second layer (<NUM>) opposite the first layer (<NUM>), the third layer (<NUM>) being coupled to the tissue site by the adhesive;
wherein the first layer (<NUM>) comprises a biasing element which biases the first layer (<NUM>) to the unloaded state;
wherein the first layer (<NUM>) can be deflected from the unloaded state to the loaded state;
wherein the first layer (<NUM>) radially pulls on the tissue site to increase lymphatic flow through the tissue site.