Wound therapy apparatus with scar modulation properties and related methods

A wound therapy apparatus is disclosed herein. In various aspects, the wound therapy apparatus may include a distal layer to contact a wound bed, the distal layer comprised of silicone, and fenestrations disposed about the distal layer pass between a distal side of the distal layer and a proximal side of the distal layer to communicate between the distal side and the proximal side. A pad may cooperate with the proximal side of the distal layer to receive exudate communicated through the distal layer from the wound bed via the fenestrations, in various aspects. Various materials including medicament(s) may be communicated to the wound bed through the distal layer via the fenestrations, in various aspects. A structural member may be included in various aspects to secure the distal layer and pad to a skin surface, in various aspects. Methods of use of the wound therapy apparatus are disclosed herein. This Abstract is presented to meet requirements of 37 C.F.R. § 1.72(b) only, and is not intended to identify key elements of the apparatus, methods, and compositions of matter disclosed herein or to delineate the scope thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application hereby incorporates by reference in the entirety herein the co-pending U.S. patent application Ser. No. 15/663,708 entitled “DEFORMATION RESISTANT WOUND THERAPY APPARATUS AND RELATED METHODS OF USE,” co-pending U.S. patent application Ser. No. 15/663,709 entitled “AUGMENTED PRESSURE THERAPY FOR WOUNDS,” co-pending U.S. patent application Ser. No. 15/663,710 entitled “CONTROL APPARATUS AND RELATED METHODS FOR WOUND THERAPY DELIVERY,” co-pending U.S. patent application Ser. No. 15/663,713 entitled “WOUND COVER APPARATUS AND RELATED METHODS OF USE,” all by Edward D. Lin as inventor and applicant and filed on 29 Jul. 2017.

BACKGROUND OF THE INVENTION

Field

This invention relates to medical devices, and more particularly, to wound therapy apparatus and related compositions of matter and methods of use.

Related Art

Wounds afflict hundreds of millions of people globally. Wounds are often traumatic, although the number of incisional wounds number over 71 million in the US. Many wounds heal with a scar that may be prominent, and, thus, stigmatize, affect esthetics, and diminish self-esteem. Hypertrophic scars such as keloids may limit function due to the thickness and restrictive nature of the scar tissue.

In order for an incisional wound to heal well and quickly with no visible or minimally visible scar formation, multiple important factors must be present, including adequate blood flow and oxygenation, absence of infection, proper moisture balance, even apposition (alignment) of wound edges with a homogenous dispersion of tension across the entire wound area. The classic ugly “railroad track” scar is typically caused by focal tension exerted by suture lines, which can be worsened yet further by a certain degree of wound dehiscence (wound edge separation). Silicone in the form of a sheet has been applied to the scar of a completely- or long-healed wound including keloids to induce collagen reconfiguration with the therapeutic goal of a less prominent scar. The silicone sheet is a barrier to exudate transfer, and, therefore, by conventional wisdom, is not suitable for use during actual wound healing.

Similarly, while various dressing including bandages, covers, compresses, and so forth that are applied to wounds during healing are labeled as including silicone, the “silicone” label refers to the presence of a silicone (instead of, for example, an acrylic) adhesive that anchors the dressing to the skin surface. The silicone in these dressings, is not in direct contact with the wound, and because the silicone adhesive is easy to peel off the skin. These dressings take weeks or longer to work, and may be ineffective in mitigating scarring.

Accordingly, there is a need for improved apparatus as well as related methods for wound therapy that may, for example, reduce scarring while protecting the wound during the healing process.

BRIEF SUMMARY OF THE INVENTION

These and other needs and disadvantages may be overcome by the wound therapy apparatus and related methods of use disclosed herein. Additional improvements and advantages may be recognized by those of ordinary skill in the art upon study of the present disclosure.

In various aspects, the wound therapy apparatus disclosed herein may include a distal layer to contact a wound bed, the distal layer comprised of silicone, and fenestrations disposed about the distal layer pass between a distal side of the distal layer and a proximal side of the distal layer to communicate between the distal side and the proximal side. A pad may cooperate with the proximal side of the distal layer to receive exudate communicated through the distal layer from the wound bed via the fenestrations, in various aspects. Various materials including medicament(s) may be communicated to the wound bed through the distal layer via the fenestrations, in various aspects. A structural member may be included in various aspects to secure the distal layer and pad to a skin surface, in various aspects.

Methods of use of the wound therapy apparatus are disclosed herein. In various aspects, the methods of use may include the step of contacting a distal side of a distal layer of said wound therapy apparatus with a wound bed, the distal layer comprising silicone with fenestrations passing between the distal side of the distal layer and a proximal side of the distal layer. The methods of use may include the step of removing exudate from the wound bed by communicating exudate from the distal side of the distal layer to the proximal side of the distal layer. The methods of use may include the step of moderating scar formation by contacting the wound bed with the distal layer comprising silicone throughout healing of the wound bed.

This summary is presented to provide a basic understanding of some aspects of the apparatus and methods disclosed herein as a prelude to the detailed description that follows below. Accordingly, this summary is not intended to identify key elements of the apparatus, methods, and compositions of matter disclosed herein or to delineate the scope thereof.

The Figures are exemplary only, and the implementations illustrated therein are selected to facilitate explanation. The number, position, relationship and dimensions of the elements shown in the Figures to form the various implementations described herein, as well as dimensions and dimensional proportions to conform to specific force, weight, strength, flow and similar requirements are explained herein or are understandable to a person of ordinary skill in the art upon study of this disclosure. Where used in the various Figures, the same numerals designate the same or similar elements. Furthermore, when the terms “top,” “bottom,” “right,” “left,” “forward,” “rear,” “first,” “second,” “inside,” “outside,” and similar terms are used, the terms should be understood in reference to the orientation of the implementations shown in the drawings and are utilized to facilitate description thereof. Use herein of relative terms such as generally, about, approximately, essentially, may be indicative of engineering, manufacturing, or scientific tolerances such as ±0.1%, ±1%, ±2.5%, ±5%, or other such tolerances, as would be recognized by those of ordinary skill in the art upon study of this disclosure.

DETAILED DESCRIPTION OF THE INVENTION

A wound therapy apparatus is disclosed herein. In various aspects, the wound therapy apparatus includes a distal layer that contacts a wound bed, the distal layer being comprised, at least in part, of silicone that may be generally in the form of a sheet. The wound bed may be in various states of healing ranging from a newly created wound bed to a wound bed that has nearly healed over. The distal layer includes fenestration that pass between a distal side of the distal layer that may contact the wound bed and a proximal side of the distal layer, in various aspects. A pad may cooperate with the fenestrations on the proximal side of the distal layer to absorb exudate communicated from the wound bed through the fenestrations or to communicate material(s) to the wound bed through the fenestrations, in various aspects.

In some aspects, the wound therapy apparatus includes a structural member that cooperates mechanically with the distal layer and with the pad, if present, and the structural member may be adhesively attachable to a skin surface around the wound bed to hold the distal layer in contact with the wound bed by an adhesive layer disposed about the structural member. The structural member may protect the wound bed, the distal layer, and the pad, when the pad is present. The structural member may maintain the distal layer and the pad in relation to one another, in certain aspects.

Methods of use of the wound therapy apparatus are disclosed herein. In various aspects, the methods of use may include the step of contacting the distal side of the distal layer with an unhealed wound bed, the distal layer comprising silicone with fenestrations passing between the distal side of the distal layer and a proximal side of the distal layer, and the step of removing exudate from the wound bed by communicating exudate from the distal side of the distal layer to the proximal side of the distal layer. Methods of use of the wound therapy apparatus may include the step of moderating scar formation by exposing the wound bed to the distal layer comprising silicone, at least in part, and having fenestrations therethrough throughout healing of the wound bed. Methods of use of the wound therapy apparatus may include the step of intermittently replacing a wound interface throughout healing of the wound bed, the wound interface, in certain aspects, comprising the distal layer, the pad, and the structural member. Methods of use of the wound therapy apparatus may include the step of intermittently replacing the distal layer during healing of the wound bed.

Silicone, as used herein, includes siloxane, various polysiloxanes, silicone-like materials, and various combinations thereof that may be generally solid. Silicone may have the chemical formula [R2SiO]n, where R is an organic group. Silicone may include, for example, silicone polymers having an average molecular weight in excess of 100,000 (e.g., between about 100,000 and about 10,000,000). Examples may include, but are not limited to, crosslinked siloxanes (e.g., crosslinked dimethicone or dimethicone derivatives), copolymers such as stearyl methyl-dimethyl siloxane copolymer, polysilicone-11 (a crosslinked silicone rubber formed by the reaction of vinyl terminated silicone and (methylhydro dimethyl)polysiloxane in the presence of cyclomethicone), cetearyl dimethicone/vinyl dimethicone crosspolymer (a copolymer of cetearyl dimethicone crosslinked with vinyl dimethyl polysiloxane), dimethicone/phenyl vinyl dimethicone crosspolymer (a copolymer of dimethylpolysiloxane crosslinked with phenyl vinyl dimethylsiloxane), and dimethicone/vinyl dimethicone crosspolymer (a copolymer of dimethylpolysiloxane crosslinked with vinyl dimethylsiloxane).

Fluid, as used herein, includes, liquid(s), gas(ses), and combinations thereof. In various aspects, material, as used herein, includes solid(s), liquid(s), and gas(ses), and material may include one or more medicament(s). Exudate, as used herein, includes, for example, proteinaceous liquids exuded from the wound bed, along with various plasma, blood and cellular components, and other liquids that may be exuded by the wound bed. Exudate may also include other liquids such as perspiration from the skin surface surrounding the wound bed, other liquids as may be present on or about the wound bed or the skin surface proximate the wound bed. Exudate, as used herein, may include gas(ses) such as CO2and water vapor exhaled from the skin surface.

In various aspects, the term fluid-tight or related terms, as used herein, means sufficiently leak-resistant to allow insufflation or vacuum suction to create pressure p0that may be above or below ambient pressure pamb. The term fluid-tight means sufficiently leak-resistant to substantially retain fluids including both gasses and liquids within the enclosed space, in certain aspects. In certain aspects, fluid tight means sufficiently leak-resistant to maintain pressure p0within the enclosed space that may be above or below ambient pressure pamb.

Wound bed, as used herein, means a focal breach in the external surface of normal skin, for example, from trauma (such as abrasion, avulsion, tearing, piercing, cutting, chemical or thermal injury) or microbial infection. The wound bed may include varying degrees of exposure of underlying layers and structures, along with possible infections and tissue changes. The wound bed represents an unhealed wound. In contrast, a healed wound is a skin surface that was previously injured but the focal breach is now entirely sealed and covered by varying amounts of epidermis and scar tissue.

As used herein the terms distal and proximal are relative, not necessarily absolute positional terms defined from the point of view of a caregiver, including physicians, nurses and technicians, treating a patient with the wound therapy apparatus. A distal portion of the wound therapy apparatus may be oriented toward the patient while a proximal portion of the wound therapy apparatus may be oriented toward the physician. When deployed, for example, a distal portion of the wound therapy apparatus may be closer to the patient while a proximal portion of the wound therapy apparatus may be closer to the caregiver. As a further example, a distal surface in a multi-layer wound interface is closer to the wound bed, but not necessarily the layer in contact with or closest to the wound bed.

FIG.1Bdepicts cross-section1B-1B ofFIG.1Awith wound interface115illustrated as set apart from wound bed113and skin surface111for purposes of clarity of explanation, it should be understood that wound interface115is actually secured to skin surface111. In this implementation, distal side182of distal layer180contacts wound bed113and adhesive190contacts skin surface111outside of wound boundary112of wound bed113so that there is no contact between adhesive190and wound bed113when wound interface is secured to skin surface111.

As illustrated inFIG.1B, pad170is interposed between structural member120and distal layer180, distal side172of pad170is in biased engagement with proximal side184of distal layer180, and proximal side174of pad170is faced toward distal side122of structural member120. Pad170in biased engagement with distal layer180forms a combination structure150, as illustrated inFIG.1C. In some implementations, proximal side174of pad170may be secured to distal side122of structural member120, while, in other implementations, proximal side174of pad170may be generally disposed about distal side122of structural member120but engaged with structural member120by engagement with distal layer180and not directly engaged with structural member120. In this implementation, structural member120, pad170, and distal layer180are engaged with respect to one another in various ways, and structure150is secured to structural member120in various ways, as would be readily recognized by those of ordinary skill in the art upon study of this disclosure.

Structural member120may be, formed, for example, of a layer of polyurethane, fabric, polyethylene, polyvinyl chloride, or latex, and structural member120may be conformable to skin surface111proximate wound bed113. In some implementations, structural member120and adhesive190have a suitable moisture-vapor transfer rate (MVTR) that allows for passage of O2, CO2, and water vapor from distal side122to proximal side124so that the skin surface111underneath may breathe, while generally excluding unwanted elements such as bacteria or water to protect wound bed113from external contamination. Although “breathable” in terms of transpiration, structural member120and adhesive190may be fluid tight as defined herein such that wound interface115is occlusive and usable for pressure therapy. Adhesive190may be formed, for example, of silicone based adhesive, acrylic, hydrocolloid, or other suitable medical adhesives. Adhesive190as a silicone based adhesive may have a lower tack than acrylic adhesive, and thus may be used when skin surface111is delicate or sensitive such as in neonates and the elderly to avoid damage to the skin surface111during removal of wound interface115.

Because distal layer180is formed, at least in part, of silicone135, in this implementation, distal layer180may not adhere to wound bed113, for example, by adhesion of granulation tissues in wound bed113to distal side182of distal layer180. In addition to such non-adhesion properties, the silicone135of distal layer180may modulate the expression of two counteracting growth factors, fibroblast growth factor β (FGF β) and tumor growth factor β (TGF β) in wound bed113. TGF β may stimulate fibroblasts to synthesize collagen and fibronectin. FGF β may normalize the collagen synthesis in wound bed113and may increases the level of collagenases that break down excess collagen. Distal layer180may thus restore the homeostatic balance of fibrogenesis and fibrolysis in wound bed113. Distal layer180may increase hydration of stratum corneum, thereby facilitating regulation of fibroblast production and reduction in collagen production in wound bed113. Such reversal of excessive collagen formation may result in a softer and flatter scar as wound bed113heals. The silicone135of distal layer180may reduce itching and discomfort associated with wound bed113as wound bed113heals.

Because silicone135has a high coefficient of friction, when wound bed113is formed as a linear wound, including an incisional wound that is at risk of dehiscence, distal layer180may aid in apposing the two sides of the linear wound together, thereby reducing the likelihood of healing by secondary intentions that would, in turn, result in a prominent wide scar. Distal layer180may provide additional benefits to wound bed113when contacted with wound bed113, in various other implementations. Texture, such as texture864(seeFIG.8), included on distal side182of distal layer180may increase the coefficient of friction of distal side182of distal layer180.

Fenestrations160may be sized in both quantity, distribution about distal layer, and aperture size to optimize transfer of exudate118from wound bed113, for example, during different stages of healing of wound bed113. For example, when wound bed113is formed as an acute wound, exudate118from wound bed113may be thin (less viscous), and, thus, the fenestrations160may be relatively small. As another example, when wound bed113is formed as a chronic wound, exudate118from wound bed113may be more viscous, and, accordingly, fenestrations160may be larger or more plentiful.

Pad170may be formed, at least in part of, for example, polyvinyl alcohol, polyurethane foam, polyurethane foam with polyethylene glycol (PEG) that may enhance absorption and transport characteristics, gauze, fiber-like materials such as sodium carboxymethyl cellulose hydrofiber (Aquacel) or knitted synthetic fibers such as polypropylene and polyamide or a combination of both with hydrophobic polypropylene fiber predominant proximate distal side172and hydrophilic polyamide fibers predominant proximate proximal side174to conduct exudate118away from wound bed113. An elastomeric fiber such as a polyester-polyurea (e.g., Spandex or Lycra) may additionally be incorporated in pad170to lend stretchability and conformability to pad170.

Pad170may include various material(s)116including medicament(s)176, such as, for example, antibiotics, analgesics such as local anesthetics, COX-2 inhibitors and nonsteroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, anti-microbial chitosan or silver compounds, bioactive factors such as the TGF-β superfamily; collagen synthesis inhibitors; cytokines, various formulations of placenta, including placental matrix powder, etc., for delivery to wound bed113through distal layer180via fenestrations160. Pad170may include various indicator(s)178such as, for example, a florescent dye that indicates the pH under UV light thus indicating the health of the wound bed113, and structural member may be formed, at least in part, of transparent or translucent material to allow viewing of the indicator. The materials that form pad170may be adjusted to accommodate such indicators or the delivery of medicament(s)176to the wound bed113. Pad170may, for example, include multiple layers formed of differing materials or each of the multiple layers including various combinations of medicament(s)176or indicator(s)178.

In certain implementations, medicament178as a liquid formulation may be pre-manufactured as a containment device adjacent to or connected to layer170and released by puncturing, removing, or opening a partition in the containment device prior to applying wound interface115to wound bed113. Alternatively, such separate containment devices may be added to or engaged with layer170prior to application of wound interface115via a syringe or via optional injection or intake ports.

As illustrated inFIG.1C, perimeter153of structure150is offset from edge123of structural member120by length155to prevent exposure of structure150when structural member120is secured to skin surface111. In other implementations, length155may be negligible so that perimeter153is coextensive with edge123. Perimeter153of structure150may be offset from adhesive190by length157. Length157may be selected to avoid contact between wound bed113and adhesive190when wound interface115is secured to skin surface111and distal layer180contacts wound bed113.

As illustrated inFIG.1C, distal layer180and pad170of wound therapy apparatus100are coextensive with one another in structure150, but this need not be the case in other implementations. Structural member120is illustrated as largely rectangular in shape with structure150disposed medially, and structure150is illustrated as having a rectangular shape. Structure150may be variously disposed about structural member120, and structure150and structural member120may have various other geometric shapes, such as square, circular, oval, and the shapes of structural member120and structure150may be similar to one another or dissimilar from one another, in other implementations. Such other geometric shapes and dispositions may have equivalencies of lengths, such as lengths155,157, between a structure, such as structure150, and an edge, such as edge123,193, as may be appropriate. For clarity of explanation,FIG.1C, as well as the other Figures illustrative of wound therapy apparatus100, does not show release liner layer(s) that may be included in various implementations of wound therapy apparatus100, as would be readily recognized by those of ordinary skill in the art upon study of this disclosure.

FIG.2illustrates distal layer180of exemplary wound therapy apparatus100including fenestrations160disposed about distal layer180that pass through distal layer180between distal side182and proximal side184. Exudate118may be communicated between distal side182and proximal side184of distal layer180through the fenestrations160and material116may be communicated between proximal side184and distal side182of distal layer180through fenestrations160. Fenestrations160in exemplary wound therapy apparatus100are illustrated as circular in geometry defining cylinders between proximal side184and distal side182. Fenestrations, such as fenestrations160, may have different shapes and sizes and may be distributed in regular and irregular patterns, in various implementations.

Thickness187of distal layer180may vary depending upon the type of wound bed113and degree of exudation with which wound interface115is employed. Thickness187may range from about 0.1 mm to about 2 mm, in certain implementations. Thickness187may range from about 0.2 mm to about 1 mm, in certain implementations. Distal side182may be flat or may include various textures, such as texture864, as may depend upon the type of wound bed113with which wound interface115is employed. As thickness187increases, distal layer180may become less susceptible to stretch and distortion. In various implementations, the size of fenestrations160in distal layer180may generally range from about 250 microns to 2500 microns in diameter or equivalent, or from about 500 microns (#35 Mesh) to about 1000 microns (#18 Mesh) in diameter or equivalent. The number of fenestrations160in distal layer180per cm2may range from about 25 per cm2to about 200 per cm2, in certain implementations.

As illustrated inFIG.3, wound therapy apparatus200includes wound interface215, and wound interface includes structural member220, pad270, and distal layer280. Structural member220, pad270, and distal layer280are oblong in shape, and pad270is disposed between distal layer280and structural member220, as illustrated. Border223of length255extends perimetrically around distal side222of structural member220to surround pad270in combination with distal layer280. Adhesive, such as adhesive190,690,790, disposed on at least portions of border223may secure wound interface215to skin surface211around wound bed213. In some implementations of wound interface215, structural member220is fluid tight and the adhesive sealingly secures wound interface215to the skin surface211around wound bed213to enclose pad270and distal layer280, thereby forming an enclosed space217that is fluid tight over wound bed213, i.e., wound interface215secured to skin surface211is occlusive. In such implementations, a port may be disposed about wound interface215for fluid communication through structural member220with enclosed space217.

As illustrated inFIG.3, fenestrations260pass between distal side282and proximal side284of distal layer280. Distal layer280, in this implementation, is formed, at least in part of silicone235. Fenestrations260disposed about distal layer280are illustrated as either square or star-burst shaped, and fenestrations260allow the communication of exudate218, material216, or both exudate218and material216between distal side282and proximal side284of distal layer280, as illustrated.

As illustrated inFIG.3, window227formed of transparent or translucent material is disposed in structural member220between proximal side224and distal side222. For example, window227may be formed of a polypropylene or polyethylene film that is sealed against a linear aperture within layer220. A user may view at least portions of pad270, for example, to determine a degree of saturation of pad270by exudate, such as exudate218. As another example, an indicator, such as indicator178, may be included in pad270, and the indicator may be viewed through window227, the indicator being indicative of the pH of pad270, and, thus, indicative of conditions of wound bed213.

FIG.4illustrates distal layer380and pad370of exemplary wound therapy apparatus300. Pad370conforms in shape to distal layer380with both pad370and distal layer380being circular in shape, in this implementation. Pad370has distal side372and proximal side374, and distal side372of pad370is secured to proximal side384of distal layer380, as illustrated. Distal layer380is formed, at least in part, of silicone335, and pad370may be formed of materials similar to those of pad170of exemplary wound therapy apparatus100, in this implementation. Fenestrations360disposed about distal layer380pass between distal side382and proximal side384of distal layer380, in this implementation. As illustrated inFIG.4, the fenestrations360are formed as Z-shaped slits. Note that fenestrations360decrease in size and increase in concentration within a central region of distal layer380within boundary385while fenestrations360are regularly sized and distributed outside boundary385, as illustrated inFIG.4.

FIG.5illustrates distal layer480, which is formed, at least in part, of silicone435, in exemplary wound therapy apparatus400, and distal layer480including fenestrations460that pass between distal side482and proximal side484of distal layer480to allow communication of material416and exudate418between distal side482and proximal side484. InFIG.5, distal layer480has an elongated rectangular shape, and fenestrations460are formed as star-burst shaped slits passing between distal side482and proximal side484of distal layer480.

FIGS.6A,6Billustrate exemplary wound therapy apparatus500including distal layer580formed, at least in part, of silicone535and pad570. As illustrated inFIG.6A, distal layer580is formed over the distal side572of pad570, and distal layer580does not occlude the entire distal side572of pad570. Distal layer580may be formed, for example, by rolling, spraying, or otherwise applying a layer of silicone material in pattern587over the distal side572of the pad570during manufacture. Various stencils, masks, screens, and so forth may be used to form pattern587.

The silicone material may be, for example, silicone gel that may include one or more polysiloxanes, silicone dioxide, and a carrier formed of a volatile solvent, in various implementations. An example of a silicone gel is a dispersion of polysilicone-11 in phenyltrimethicone as carrier. Following application of the silicone gel to the distal side572of pad570, the carrier, such as phenyltrimethicone, evaporates leaving the silicone535in place on distal side572of the pad570as distal layer580with pattern587. The combined pad570and distal layer580then be die-cut and then assembled on the distal side of a structural member, such as structural member120,620,720.

FIG.6Aillustrates distal side582of distal layer580. As illustrated in the detail ofFIG.6A, distal layer580is formed, at least in part, of silicone535with pattern587, and pad570may be formed of materials similar to those of pad170of exemplary wound therapy apparatus100. While pattern587is illustrated as generally of a regular rectangular geometry, pattern587may have various shapes, combinations of regularity and irregularity, and size distributions, in other implementations. Pattern587of distal layer580defines occluded regions533with fenestrations560between occluded regions533that expose distal side572of pad570to allow communication of exudate518or material516between distal side582and proximal side584of distal layer580and with distal side572of pad570, as illustrated inFIGS.6A,6B. Thickness589of distal layer580may range from about 200 microns to about 1000 microns, in various implementations. Fenestrations560may range from about 50 microns (#270 Mesh) to about 1000 microns (#18 Mesh) in diameter or equivalent, or from about 100 microns (#140 Mesh) to about 750 microns (about #22 Mesh) in diameter or equivalent. The number of fenestrations560per cm2may generally range from about 45 per cm2to about 2500 per cm2, in various implementations.

FIG.7Aillustrates wound interface615of exemplary wound therapy apparatus600set apart from wound bed613and skin surface611for purposes of clarity of explanation. Wound bed613includes skin graft615, in this implementation. Wound interface615includes distal layer680and pad670in cooperation with structural member620with pad670interposed between distal layer680and structural member620. Distal layer680is formed, at least in part, of silicone635, in this implementation. Adhesive690disposed about structural member620may affix structural member620, and, thus, wound interface615to skin surface611to bias distal layer680against wound bed613, in this implementation. Exudate618may be communicated through fenestrations660in proximal layer from wound bed613to pad670, and material616may be communicated from pad670through fenestrations660to wound bed613, as illustrated.

Shear force Fs, is illustrated inFIG.7Aas acting tangentially upon wound interface615of wound therapy apparatus600. Shear force Fs, may arise from various impacts having a tangential component upon wound interface615as may be incurred during the course of wearing of wound interface615, for example, due to bumping on objects and interactions with clothing or bedding.

In the implementation ofFIG.7A, wound interface615includes spacer640having an envelope-like construction and located between adhesive690, which is disposed over distal side622of structural member620, and pad670. In other implementations, spacer640may be located between structural member620and adhesive690. Spacer640includes distal layer642and proximal layer644, and distal layer642and proximal layer644define space646in between, as illustrated. Spacer640may be formed as a film of a low-friction material625such as polyethylene or polypropylene for slideable engagement of proximal layer644with distal layer642. The slideable engagement of proximal layer644with distal layer642in spacer640may at least partially deflect shear force Fs, to reduce the transmission of shear force Fs, to distal layer680, and thence to wound bed613. Proximal side624of structural member620may be formed of low friction material625in order to deflect shear force Fs, for example, to allow slippage between proximal side624and objects that contact proximal side624. Accordingly, shear reducing means for reducing the transmission of shear force Fs, to wound bed613may include spacer640having proximal layer644and distal layer642with space646therebetween, and the shear reducing means may include proximal side624of structural member620formed of low friction material625.

Ab initio, the skin graft615is devoid of vascular connection. After a period of time, neovascular twigs begin to appear, reaching from the wound bed towards the skin graft615and ultimately establishing blood flow and viability of the graft. If the wound bed613including skin graft615is sheared during the vascularization period, the viability of the skin graft615is threatened. Thus, inclusion of spacer640or a low friction material625in proximal side624of structural member620may protect wound bed613including skin graft from disruption by shear force Fs, by reducing of the transmission of shear force Fs, to wound bed613or deflecting shear force Fs, respectively.

FIG.7Billustrates wound interface715of exemplary wound therapy apparatus600including pad770interposed between distal layer780and structural member720. Wound interface715is illustrated as set apart from wound bed713and skin surface711for clarity of explanation. Distal layer780is formed, at least in part, of silicone735, and distal layer780includes fenestrations760for the communication of exudate718and material716therethrough. Layer742is interposed between adhesive layer790and proximal side774of pad770with space746between layer742and proximal side774of pad770, as illustrated. Layer742may be formed as a film of a low-friction material725such as polyethylene or polypropylene to facilitate slideable engagement between layer742and proximal side774of pad770that may reduce the transmission of shear force Fsapplied to proximal side724of structural member to distal layer780. As illustrated, layer742prevents adhesion of at least portions of pad770to structural member720by adhesive790, and slideable engagement of layer742with proximal side774of pad allows movement between portions of structural member720and pad770to at least partially deflect shear force Fsapplied to proximal side724of structural member720. This may reduce the transmission of shear force Fsto wound bed713. In other implementations, for example, adhesive790may be omitted from portions of structural member790proximate proximal side774of pad770and layer742may be omitted so that at least portions of proximate proximal side774of pad770are slideably engaged with structural member720to allow movement between portions of structural member720and pad770that may least partially deflect shear force Fsapplied to proximal side724of structural member720. Accordingly, shear reducing means for reducing the transmission of shear force Fsto wound bed713may include, for example, layer742with space746.

FIG.8illustrates distal layer880of exemplary wound therapy apparatus800, and distal layer880is formed, at least in part, of silicone835. As illustrated inFIG.8, the fenestrations860a,860b,860c,860d,860e,860fpassing between distal side882and proximal side884have a square, rectangular, starburst, circular, slit, and fish-mouthed geometries, respectively, and may be disposed about distal layer880in various fenestration patterns. Exudate818or material816may be communicated through fenestrations860a,860b,860c,860d,860e,860fbetween distal side882and proximal side884. Geometry of fenestrations, such as fenestrations860a,860b,860c,860d,860e,860f, and fenestration patterns may be selected to preserve patency of the fenestrations during use that allows communication of exudate818or material816through the fenestrations. For example, fenestrations that are Z-shaped (e.g., fenestrations360inFIG.4) may be more likely to remain functionally patent than simple slits because the Z-shape may allow for more multidirectional stretching of the distal layer. Fish-mouthed fenestrations, such as fenestrations860f, may also exhibit increased patency.

FIG.8illustrates texture864on distal surface882of distal layer880that may be micro- or macro-surface textures in the form, for example, of bumps, pits, ridges, and combinations thereof. Texture864when biased against a wound bed, such as wound bed113,213,613,713may cause micro-deformation and pressure points that may accelerate wound healing by stimulating cellular mitosis, differentiation, and angiogenesis.

As illustrated herein, the wound therapy apparatus, in some implementations, may include a distal layer, such as distal layer180,280,680,780, a pad, such as pad170,270,670,770, and a structural member, such as structural member120,220,620,720, as in wound therapy apparatus100,200,600,700. The wound therapy apparatus, in other implementations, may include a distal layer, such as distal layer380,580, and a pad, such as pad370,570, as in wound therapy apparatus300,500. The wound therapy apparatus, in yet other implementations, may include a distal layer, such as distal layer480, as in wound therapy apparatus400.

In various exemplary methods of operation, for example, a distal layer, such as distal layer180,280,380,480,580,680,780,880of a wound therapy apparatus, such as wound therapy apparatus100,200,300,400,500,600,700,800may be contacted with a wound bed, such as wound bed113,213,613, for example, shortly after injury and before scar formation takes place. The distal layer, which is formed, at least in part, of silicone, such as silicone135,235,335,435,535,635,735,835, may provide an early homeostatic influence and may balance the collagen, fibronectin and collagenase levels in order to promote healing and reduce scarring that may obviate the protracted need for reversing excessive scarring after a scar had already formed.

In one exemplary method of operation, for example, the wound bed, which is unhealed, is contacted with the distal layer, which is formed, at least in part, of silicone, and the distal layer is employed essentially by itself with the pad, such as pad170,270,370,470,570,670,770and the structural member, such as structural member120,200,620,720being omitted.

In another exemplary method of operation, the wound bed is contacted with the distal layer, and the distal layer is engaged with the pad, the structural member being omitted. In such exemplary methods of operation, the pad absorbs exudate, such as exudate118,218,418,518,618,818, communicated to the pad from the wound bed through fenestrations, such as fenestration160,260,360,460,560,660,760,860a,860b,860c,860d,860e,860f, in the distal layer. Material, such as material116,216,416,516,616,816, may be communicated to the wound bed through the fenestrations.

In a third exemplary method of operation, the wound bed is contacted with the distal layer, and the distal layer is engaged with the pad, and the structural member is deployed to cover the structure, such as structure150, that includes the combination of distal layer with pad. The structural member may protect the pad, the distal member, or the pad in combination with the distal member, and the structural member may protect the wound bed.

In methods of operation that include the pad, the distal layer and the pad may be removed and then discarded when indicated, for example, when the pad is at least partly saturated with exudate. In some operations, a wound interface, such as wound interface115,215,615,715may be removed and replaced with another wound interface that may be either similar to or dissimilar from the wound interface that was removed. Different wound interfaces may be used during the course of treatment of the wound bed, for example, as the amount of exudate exuded by the wound bed decreases or to deliver various medicaments, such as medicament176, to the wound bed.

Various methods of operation may include delivery of the medicament to the wound bed through the distal layer from the pad. Various methods of operation may include contacting the wound bed with texture, such as texture864, disposed about the distal side of the distal layer that may accelerate healing of the wound bed or may aid in apposition of the wound bed. Various methods of operation may include observing the pad through a window, such as window227, disposed about the structural member. Various methods of operation may include observing an indicator, such as indicator178, included in the pad, and the indicator may be observed through the window. Various methods of operation may include decreasing the shear force Fstransmitted though the wound interface to the wound bed. Various methods of operation may include removing exudate or fluid from the wound interface via one or more ports disposed about the wound interface, and may include inputting fluid into the wound interface via one or more ports disposed about the wound interface.

The foregoing discussion along with the Figures discloses and describes various exemplary implementations. These implementations are not meant to limit the scope of coverage, but, instead, to assist in understanding the context of the language used in this specification and in the claims. Upon study of this disclosure and the exemplary implementations herein, one of ordinary skill in the art may readily recognize that various changes, modifications and variations can be made thereto without departing from the spirit and scope of the inventions as defined in the following claims.