Patent Description:
While the clinical benefits of negative-pressure therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients. <CIT> discloses a reduced pressure treatment system for treating linear wounds. <CIT> discloses a system for applying reduced pressure to a tissue site using a self-contained reduced-pressure dressing. <CIT> discloses a system for providing reduced pressure to a tissue site using a wireless source of power.

A selection of optional features is set out in the dependent claims.

Insofar as the term invention or 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.

Reference(s) 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 a simplified functional block diagram of an example embodiment of a therapy system <NUM> that can provide negative-pressure 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. For example, negative pressure may be applied to a tissue site to grow additional tissue that may be harvested and transplanted.

The therapy system <NUM> may include a source or supply of negative pressure, such as a negative-pressure source <NUM>, a dressing <NUM>, a fluid container, such as a container <NUM>, and a regulator or controller, such as a controller <NUM>, for example. As illustrated in <FIG>, for example, the therapy system <NUM> may include one or more sensors coupled to the controller <NUM>, such as a first sensor <NUM> and a second sensor <NUM>. As illustrated in the example of <FIG>, the dressing <NUM> may comprise or consist essentially of a tissue interface <NUM>, a cover <NUM>, or both in some embodiments.

Some components of the therapy system <NUM> 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 <NUM> may be combined with the controller <NUM> and other components into a therapy unit.

For example, the negative-pressure source <NUM> may be directly coupled to the container <NUM>, and may be indirectly coupled to the dressing <NUM> through the container <NUM>. For example, the negative-pressure source <NUM> may be electrically coupled to the controller <NUM>, and may be fluidly coupled to one or more distribution components to provide a fluid path to a tissue site.

A distribution component is preferably detachable, and may be disposable, reusable, or recyclable. The dressing <NUM> and the container <NUM> are illustrative of distribution components. ™ Pad available from KCI of San Antonio, Texas.

A negative-pressure supply, such as the negative-pressure source <NUM>, 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 applied to a tissue site may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -<NUM> Hg (-<NUM> Pa) and -<NUM> Hg (-<NUM> kPa). Common therapeutic ranges are between -<NUM> Hg (-<NUM> kPa) and -<NUM> Hg (-<NUM> kPa).

In some embodiments, for example, the first sensor <NUM> may be a piezoresistive strain gauge. The second sensor <NUM> may optionally measure operating parameters of the negative-pressure source <NUM>, such as the voltage or current, in some embodiments.

The tissue interface <NUM> 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. Moreover, any or all of the surfaces of the tissue interface <NUM> may have projections or an uneven, course, or jagged profile that can induce strains and stresses on a tissue site, which can promote granulation at the tissue site.

In some embodiments, the tissue interface <NUM> may be a manifold. A "manifold" in this context generally includes any substance or structure providing a plurality of pathways adapted to collect or distribute fluid across a tissue site under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across a tissue site, 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 across a tissue site.

In some illustrative embodiments, the pathways of a manifold may be interconnected to improve distribution or collection of fluids across a tissue site. In some illustrative embodiments, a manifold may be a porous foam material having interconnected cells or pores. For example, open-cell foam, porous tissue collections, and other porous material such as gauze or felted mat generally include pores, edges, and/or walls adapted to form interconnected fluid channels. 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 comprise projections that form interconnected fluid pathways. For example, a manifold may be molded to provide surface projections that define interconnected fluid pathways.

The average pore size of foam may vary according to needs of a prescribed therapy. For example, in some embodiments, the tissue interface <NUM> may be foam having pore sizes in a range of <NUM>-<NUM> microns. The tensile strength of the tissue interface <NUM> may also vary according to needs of a prescribed therapy. For example, the tensile strength of foam may be increased for instillation of topical treatment solutions. In some examples, the tissue interface <NUM> may be reticulated polyurethane foam such as found in GRANUFOAM™ dressing or V. VERAFLO™ dressing, both available from KCI of San Antonio, Texas.

The tissue interface <NUM> may be either hydrophobic or hydrophilic. In an example in which the tissue interface <NUM> may be hydrophilic, the tissue interface <NUM> may also wick fluid away from a tissue site, while continuing to distribute negative pressure to the tissue site. The wicking properties of the tissue interface <NUM> may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of hydrophilic foam is a polyvinyl alcohol, open-cell foam such as V. WHITEFOAM™ dressing available from KCI of San Antonio, Texas. 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.

The tissue interface <NUM> may further promote granulation at a tissue site when pressure within the sealed therapeutic environment is reduced. For example, any or all of the surfaces of the tissue interface <NUM> may have an uneven, coarse, or jagged profile that can induce microstrain and stress at a tissue site if negative pressure is applied through the tissue interface <NUM>.

In some embodiments, the tissue interface <NUM> may be constructed from bioresorbable materials. Suitable bioresorbable materials may include, without limitation, a polymeric blend of polylactic acid (PLA) and polyglycolic acid (PGA). The polymeric blend may also include without limitation polycarbonates, polyfumarates, and capralactones. The tissue interface <NUM> may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface <NUM> to promote cell-growth. A scaffold is generally a substance or structure used to enhance or promote the growth of cells or formation of tissue, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, or processed allograft materials.

In some embodiments, the cover <NUM> may provide a bacterial barrier and protection from physical trauma. The cover <NUM> 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. For example, the cover <NUM> may comprise or consist essentially of 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. In some example embodiments, the cover <NUM> may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. The cover <NUM> may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least <NUM>/m^<NUM> per twenty-four hours in some embodiments (based on ASTM E96/E96M for upright cup measurement). Such drapes typically have a thickness in the range of <NUM>-<NUM> microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained.

An attachment device may be used to attach the cover <NUM> 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 <NUM> to epidermis around a tissue site. In some embodiments, for example, some or all of the cover <NUM> may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight between <NUM>-<NUM> grams per square meter (g. 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.

<FIG> is a graph illustrating additional details of an example control mode that may be associated with some embodiments of the controller <NUM>. In some embodiments, the controller <NUM> may have a continuous pressure mode, in which the negative-pressure source <NUM> is operated to provide a constant target negative pressure, as indicated by line <NUM> and line <NUM>, for the duration of treatment or until manually deactivated. Additionally or alternatively, the controller may have an intermittent pressure mode, as illustrated in the example of <FIG>. In <FIG>, the x-axis represents time, and the y-axis represents negative pressure generated by the negative-pressure source <NUM> over time. In the example of <FIG>, the controller <NUM> can operate the negative-pressure source <NUM> to cycle between a target pressure and atmospheric pressure. For example, the target pressure may be set at a value of <NUM> mmHg, as indicated by line <NUM>, for a specified period of time (e.g., <NUM>), followed by a specified period of time (e.g., <NUM>) of deactivation, as indicated by the gap between the solid line <NUM> and the solid line <NUM>. The cycle can be repeated by activating the negative-pressure source <NUM>, as indicated by the solid line <NUM>, which can form a square wave pattern between the target pressure and atmospheric pressure.

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 <NUM> and the dressing <NUM> may have an initial rise time, as indicated by the dashed line <NUM>. 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 <NUM>-<NUM> mmHg/second and in a range of about <NUM>-<NUM> mmHg/second for another therapy system. If the therapy system <NUM> is operating in an intermittent mode, the repeating rise time as indicated by the solid line <NUM> may be a value substantially equal to the initial rise time as indicated by the dashed line <NUM>.

<FIG> is a graph illustrating additional details that may be associated with another example pressure control mode in some embodiments of the therapy system <NUM>. In <FIG>, the x-axis represents time and the y-axis represents negative pressure generated by the negative-pressure source <NUM>. The target pressure in the example of <FIG> can vary with time in a dynamic pressure mode. For example, the target pressure may vary in the form of a triangular waveform, varying between a minimum and maximum negative pressure of <NUM>-<NUM> mmHg with a rise time <NUM> set at a rate of +<NUM> mmHg/min. and a descent time <NUM> set at -<NUM> mmHg/min, respectively. In other embodiments of the therapy system <NUM>, the triangular waveform may vary between negative pressure of <NUM>-<NUM> mmHg with a rise time <NUM> set at a rate of +<NUM> mmHg/min and a descent time <NUM> set at -<NUM> mmHg/min.

In some embodiments, the controller <NUM> 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 <NUM>, 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.

<FIG> is a top view of an example of the dressing <NUM>, illustrating additional details that may be associated with some embodiments. In the example embodiment of <FIG>, the dressing <NUM> includes features that can cover articulating joints, such as a knee, while still allowing for significant range of motion. For example, the dressing <NUM> of <FIG> generally comprises a manifold <NUM> having a stem <NUM>, a first arm <NUM> joined to a first end of the stem <NUM>, and a second arm <NUM> joined to a second end of the stem <NUM>.

In some embodiments, the manifold <NUM> may be characterized as a polyhedron or as a generalized cylinder. For example, in <FIG> the manifold <NUM> can be characterized as a generalized cylinder having a face <NUM> and an edge <NUM>. The edge <NUM> in <FIG> bounds the stem <NUM>, the first arm <NUM>, and the second arm <NUM>. In some embodiments, some portions of the edge <NUM> may be curved, and some portions may be straight. In <FIG>, for example, the first arm <NUM> is bounded in part by a first edge portion <NUM> that is substantially straight, and the second arm <NUM> is bounded in part by a second edge portion <NUM> that is substantially straight. In other embodiments, the first arm <NUM>, the second arm <NUM>, or both may be contoured at the extremities.

The stem <NUM> is generally configured to be positioned over an articular surface. The width of the stem <NUM> may vary for different types of joints, and may be limited to minimize interference with articulation. For example, in some embodiments, the stem <NUM> may be configured for positioning over a patella and have a width of <NUM>-<NUM> inches. In other examples, a width of <NUM>-<NUM> inches may be suitable for positioning over an olecranon.

As illustrated in the example of <FIG>, the first arm <NUM> and the second arm <NUM> flare away from the stem <NUM>. In some examples, the face <NUM> may be biconcave. More generally, portions of the edge <NUM> bounding the first arm <NUM> and the second arm <NUM> may be biconcave, converging toward the stem <NUM> to define a concave void adjacent to each side of the stem <NUM>. In the example of <FIG>, the concave void is curved. In other examples, the edge <NUM> may have straight segments that converge toward a vertex at the stem <NUM>.

Some examples of the manifold <NUM> may additionally be characterized by a line of symmetry <NUM> through the stem <NUM>, and each of the first arm <NUM> and the second arm <NUM> may be characterized by a span that is generally orthogonal to the line of symmetry <NUM>. In the example of <FIG>, a first span <NUM> between extremities <NUM> is characteristic of the first arm <NUM>, and a second span <NUM> between extremities <NUM> is characteristic of the second arm <NUM>.

In the example of <FIG>, the first span <NUM> is greater than the second span <NUM>. A suitable ratio of the span of the first span <NUM> to the second span <NUM> may generally be in a range of <NUM> to <NUM>. A ratio of <NUM> to <NUM> may be particularly advantageous for some applications. For example, in some embodiments the first span <NUM> may be in a range of <NUM>- <NUM> centimeters and the second span <NUM> may be in a range of <NUM>-<NUM> centimeters. In other examples, the first span <NUM> may be in a range of <NUM>-<NUM> centimeters and the second span <NUM> may be in a range of <NUM>-<NUM> centimeters.

In some embodiments, a fluid conductor <NUM> may be coupled to the dressing <NUM>. As illustrated in <FIG>, the fluid conductor <NUM> may be coupled to the first arm <NUM>. <FIG> also illustrates an example of a dressing interface <NUM> that may be used to facilitate fluidly coupling the fluid conductor <NUM> to the manifold <NUM>.

<FIG> is an assembly view of the dressing <NUM> of <FIG>, illustrating additional details that may be associated with some examples. In the example of <FIG>, the cover <NUM>, the manifold <NUM>, an adhesive ring <NUM>, and an attachment device <NUM> with a treatment area aperture <NUM> are disposed in a stacked relationship. In general, the cover <NUM>, the manifold <NUM>, the adhesive ring <NUM>, and the attachment device <NUM> of <FIG> have similar shapes. The attachment device <NUM> may be slightly larger than the manifold <NUM>, and the adhesive ring <NUM> can bond a peripheral portion of the manifold <NUM> to an interior portion of the attachment device <NUM>. The manifold <NUM> can be exposed through the treatment area aperture <NUM>. In some embodiments, an adhesive may be disposed on at least portions of the manifold <NUM> exposed through the treatment area aperture <NUM>. For example, portions of the first arm <NUM>, the second arm <NUM>, or both may have an adhesive coating. In some embodiments, the adhesive may be pattem-coated, and may cover up to <NUM>% of the surface. The dressing <NUM> may optionally include one or more release liners, such as a center release liner <NUM>, a first side release liner <NUM>, and a second side release liner <NUM>. In some examples, the dressing <NUM> may have two release liners, each of which may have perforations or slits configured to allow the release liners to be separated into smaller pieces for removal. Additionally, some embodiments may also have one or more casting sheet liners <NUM>.

In some embodiments, the attachment device <NUM> may be a sealing ring. Similar or analogous to the cover <NUM>, a suitable sealing ring may be, for example, an elastomeric film or membrane that can provide a seal in a therapeutic negative-pressure environment. In some example embodiments, the attachment device <NUM> may be a polymer film, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. The attachment device <NUM> typically has a thickness in the range of <NUM>-<NUM> microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. The attachment device <NUM> may also include a medically-acceptable, pressure-sensitive adhesive. In some embodiments, for example, the attachment device <NUM> may be a polymer film coated with an adhesive, such as an acrylic adhesive, which may have a coating weight between <NUM>-<NUM> grams per square meter (g. Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Additionally or alternatively, the attachment device <NUM> may comprise a hydrocolloid adhesive, which can substantially reduce or prevent skin irritation.

As illustrated in the example of <FIG>, some embodiments of the manifold <NUM> may have flexibility notches <NUM>. The flexibility notches <NUM> may be parallel to the line of symmetry <NUM>, perpendicular to the line of symmetry <NUM>, or both. Additionally or alternatively, one or more of the flexibility notches <NUM> may be oblique to the line of symmetry <NUM>. In some embodiments, only the stem <NUM> may have the flexibility notches <NUM>. In other embodiments, only the first arm <NUM>, the second arm <NUM>, or both may have the flexibility notches <NUM>.

The thickness of the manifold <NUM> may vary according to prescribed therapy. In some embodiments, the manifold <NUM> or some portion of the manifold <NUM> may comprise felted, open-cell foam to increase rigidity. Additionally or alternatively, the manifold <NUM> may comprise foam segments having different density. For example, the stem <NUM> may comprise or consist essentially of open-cell foam having a higher density than the first arm <NUM> and the second arm <NUM>.

The cover <NUM> may be larger than the manifold <NUM>, as illustrated in the example of <FIG>, and may have a perimeter configured to be attached to the attachment device <NUM>. For example, the cover <NUM> may have a flange <NUM>. Assembled, the cover <NUM> may be disposed over the face <NUM>, and the flange <NUM> may be attached to the attachment device <NUM> around the manifold <NUM>. For example, an adhesive may be used to adhere the flange <NUM> to the attachment device <NUM>, or the flange <NUM> may be welded, stitched, or stapled to the attachment device <NUM>. The cover <NUM> also has an aperture <NUM> and an expansion zone <NUM> in the example of <FIG>. The aperture <NUM> can allow fluid communication between the manifold <NUM> and a dressing interface or fluid conductor. The expansion zone <NUM> may comprise folds, ribs, bellows, or other means for allowing the cover <NUM> to expand if needed.

Some embodiments of the dressing <NUM> may additionally include a comfort layer (not shown) coupled to the manifold and at least partially exposed through the treatment area aperture <NUM>. The comfort layer may comprise or consist essentially of a material that substantially reduces or eliminates skin irritation while allowing fluid transfer through the comfort layer. Examples of materials that may be suitable include woven or non-woven textiles and fenestrated polymer films.

The center release liner <NUM>, the first side release liner <NUM>, and the second side release liner <NUM> may cover any adhesive on the attachment device <NUM>. Additionally or alternatively, the center release liner <NUM>, the first side release liner <NUM>, and the second side release liner <NUM> may provide stiffness to the attachment device <NUM> to facilitate handling and application. Additionally or alternatively, the casting sheet liners <NUM> may cover the flange <NUM> to provide stiffness to the cover <NUM> for handling and application.

<FIG> is a top view of another example of the dressing <NUM>, illustrating additional details that may be associated with some embodiments. The dressing <NUM> of <FIG> is similar the dressing <NUM> of <FIG> in many respects. For example, the face <NUM> of the dressing <NUM> of <FIG> may be biconcave. More generally, portions of the edge <NUM> bounding the first arm <NUM> and the second arm <NUM> may converge toward the stem <NUM> to define a concave void adjacent to each side of the stem <NUM>.

The manifold <NUM> may additionally be characterized by a line of symmetry <NUM> through the stem <NUM>, and each of the first arm <NUM> and the second arm <NUM> may be characterized by a span that is generally parallel to the line of symmetry <NUM>. In the example of <FIG>, the first span <NUM> and the second span <NUM> are substantially equal. The stem <NUM> in the example of <FIG> is offset from a center of the first span <NUM> and the second span <NUM>. Thus, the first arm <NUM> and the second arm <NUM> each have a sacrificial extension portion <NUM> on one side of the stem <NUM>.

In some embodiments, the manifold <NUM> may have distinct pressure zones. For example, the stem <NUM> may be fluidly isolated from the first arm <NUM>, the second arm <NUM>, or both. Each pressure zone may have a distinct fluid interface in some embodiments.

The cover <NUM>, the manifold <NUM>, the attachment device <NUM>, or various combinations may be assembled before application or in situ. In some embodiments, the dressing <NUM> may be provided as a single unit.

In use, the center release liner <NUM> may be removed from the dressing <NUM>, exposing a portion of the attachment device <NUM>. The manifold <NUM> may be placed within, over, on, or otherwise proximate to a tissue site, and the exposed portion of the attachment device <NUM> may be placed against epidermis adjacent to the tissue site. If the tissue site is an incision, for example, the manifold <NUM> may be placed over the incision. In some embodiments, the line of symmetry <NUM> may be aligned with some or all of the incision. If the tissue site is on a limb, the first arm <NUM> may be wrapped around a proximal portion of the limb and the second arm <NUM> may be wrapped around a distal portion of the limb. The first arm <NUM> and the second arm <NUM> may not directly contact the incision in some applications, and a stronger adhesive may be used to secure at least portions of the first arm <NUM> and the second arm <NUM> to epidermis adjacent to the incision. The first side release liner <NUM> and the second side release liner <NUM> may be removed and applied to additional epidermis adjacent to the tissue site. Thus, the dressing <NUM> can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source <NUM> can be fluidly coupled to the manifold <NUM> through the aperture <NUM>.

<FIG> illustrates the dressing <NUM> of <FIG> applied to an incision (not shown) on an articulating joint. In the example of <FIG>, the articulating joint is a knee <NUM>. As illustrated in the example of <FIG>, the stem <NUM> may substantially cover the top of the knee <NUM>. The manifold <NUM> is preferably oriented so that the first arm <NUM> and the fluid conductor <NUM> are superior to the knee <NUM>. The first arm <NUM> may cover and wrap around a portion of the leg superior to the knee <NUM>, and the second arm <NUM> may cover and wrap around a portion of the leg inferior to the knee <NUM>. In some embodiments, one or more of the first arm <NUM> and the second arm <NUM> may be cut to reduce the first span <NUM>, the second span <NUM>, or both. For example, in the dressing <NUM> of <FIG>, the extension portion <NUM> of the first arm <NUM>, the second arm <NUM>, or both may be cut so that the first arm <NUM> and the second arm <NUM> can fully wrap a portion of the leg superior and inferior to the knee <NUM>, respectively.

<FIG> is a top view of another example of the dressing <NUM>, illustrating additional details that may be associated with some embodiments. In the example embodiment of <FIG>, the dressing <NUM> includes features that can be applied to an ankle and surrounding tissue. The dressing <NUM> of <FIG> is similar the dressing <NUM> of <FIG> in many respects, and may have a similar construction. For example, the first arm <NUM> and the second arm <NUM> may flare away from the stem <NUM>. In some examples, the face <NUM> may be biconcave. More generally, portions of the edge <NUM> bounding the first arm <NUM> and the second arm <NUM> may converge toward the stem <NUM> to define a concave void adjacent to each side of the stem <NUM>. In the example of <FIG>, the concave void is curved. In other examples, the edge <NUM> may have straight segments that converge toward a vertex at the stem <NUM>. More generally, portions of the edge <NUM> bounding the first arm <NUM> and the second arm <NUM> may converge toward the stem <NUM> to define a concave void adjacent to each side of the stem <NUM>.

The manifold <NUM> of <FIG> may additionally be characterized by a line of symmetry <NUM> through the stem <NUM>, and each of the first arm <NUM> and the second arm <NUM> may be characterized by a span that is generally orthogonal to the line of symmetry <NUM>. In the example of <FIG>, the first span <NUM> is greater than the second span <NUM>. For example, in some embodiments the first span <NUM> may be in a range of <NUM>-<NUM> centimeters and the second span <NUM> may be in a range of <NUM>-<NUM> centimeters. As illustrated in <FIG>, the first arm <NUM> may be coupled to the fluid conductor <NUM>, which may be a low-profile dressing bridge.

<FIG> illustrates the dressing <NUM> of <FIG> applied to an incision (not visible) on an ankle and adjacent tissue. The stem <NUM> may be placed superior to the foot, on either the anterior or posterior side of a leg. The first arm <NUM> may be disposed over a lateral portion of the leg or over a medial portion of the leg, depending on placement of the stem <NUM>. The second arm <NUM> may also be disposed over a lateral portion or a medial portion depending on placement of the stem <NUM>. For example, if the incision is shorter than the length of the second arm <NUM>, the dressing <NUM> may be oriented so that either the first arm <NUM> or the second arm <NUM> is disposed over the incision. On other examples, if the incision is longer than the length of the second arm <NUM>, the dressing <NUM> may be oriented so that the first arm <NUM> covers the incision.

In some examples, the dressing <NUM> may be oriented to cover more than one incision. Additionally or alternatively, a support boot (not shown) may be worn over the dressing <NUM> in some examples. The fluid conductor <NUM> of <FIG> can also be partially disposed beneath the boot, and can be partially extending above a top of the boot to provide a convenient access point for coupling the dressing <NUM> to the negative-pressure source <NUM> or another distribution component.

<FIG> is a top view of another example of the dressing <NUM>, illustrating additional details that may be associated with some embodiments. In the example embodiment of <FIG>, the dressing <NUM> includes features that can cover an ankle and surrounding tissue. The dressing <NUM> of <FIG> is similar the dressing <NUM> of <FIG> in many respects. For example, the first arm <NUM> and the second arm <NUM> may flare away from the stem <NUM>. In some examples, the face <NUM> may be biconcave. More generally, portions of the edge <NUM> bounding the first arm <NUM> and the second arm <NUM> may converge toward the stem <NUM> to define a concave void adjacent to each side of the stem <NUM>. In the example of <FIG>, the concave void is curved. In other examples, the edge <NUM> may have straight segments that converge toward a vertex at the stem <NUM>. More generally, portions of the edge <NUM> bounding the first arm <NUM> and the second arm <NUM> may converge toward the stem <NUM> to define a concave void adjacent to each side of the stem <NUM>.

The manifold <NUM> of <FIG> may additionally be characterized by a line of symmetry <NUM> through the stem <NUM>, and each of the first arm <NUM> and the second arm <NUM> may be characterized by a span that is generally orthogonal to the line of symmetry <NUM>. In the example of <FIG>, the first span <NUM> is greater than the second span <NUM>. For example, in some embodiments the first span <NUM> may be in a range of <NUM>-<NUM> centimeters and the second span <NUM> may be in a range of <NUM>-<NUM> centimeters. As illustrated in <FIG>, the first arm <NUM> may have or may be coupled to an arm extension <NUM>. The fluid conductor <NUM> may be coupled to the arm extension <NUM>.

In some examples, the dressing <NUM> may be oriented to cover more than one incision. Additionally or alternatively, a support boot (not shown) may be worn over the dressing <NUM> in some examples. The arm extension <NUM> of <FIG> can also be partially disposed beneath a boot, and can be partially extending above a top of the boot to provide a convenient access point for coupling the dressing <NUM> to the negative-pressure source <NUM> or another distribution component.

In operation, the negative-pressure source <NUM> can reduce pressure in the sealed therapeutic environment. Negative pressure applied across the tissue site through the manifold <NUM> in the sealed therapeutic environment can induce macro-strain and micro-strain in the tissue site, as well as remove exudates and other fluids from the tissue site, which can be collected in the container <NUM>.

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 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.

In general, exudates and other fluids 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.

In some embodiments, the controller <NUM> may receive and process data from one or more sensors, such as the first sensor <NUM>. The controller <NUM> may also control the operation of one or more components of the therapy system <NUM> to manage the pressure delivered to the tissue interface <NUM>. In some embodiments, controller <NUM> 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 <NUM>. 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 <NUM>. 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 <NUM> can operate the negative-pressure source <NUM> 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 <NUM>. In some embodiments, the manifold <NUM> may have distinct pressure zones, and different target pressures and control modes may be applied to different pressure zones.

Claim 1:
A dressing for treating an area around an ankle with negative pressure, the dressing comprising:
an attachment device (<NUM>) having a treatment aperture (<NUM>);
a manifold (<NUM>) comprising a stem (<NUM>), a first arm (<NUM>) joined to the stem (<NUM>), and a second arm (<NUM>) joined to a second end of the stem (<NUM>), the manifold (<NUM>) at least partially exposed through the treatment aperture;
a cover (<NUM>) disposed over the manifold (<NUM>) and coupled to the attachment device around the manifold (<NUM>); and
an adhesive on the attachment device for bonding to the area around the ankle,
wherein the manifold (<NUM>) has a line of symmetry (<NUM>) through the stem (<NUM>), and each of the first arm (<NUM>) and second arm (<NUM>) has a span (<NUM>, <NUM>) that is orthogonal to the line of symmetry (<NUM>), and
the first arm (<NUM>) and the second arm (<NUM>) flare away from the stem (<NUM>) and edges of the first arm (<NUM>) and second arm (<NUM>) converge toward the stem (<NUM>) to define a concave void adjacent each side of the stem (<NUM>),
the first arm (<NUM>) has an arm extension (<NUM>) for coupling to a fluid conductor (<NUM>).