Patent Description:
Negative-pressure wound therapy (NPWT) is a type of treatment used by physicians to promote the healing of acute or chronic wounds. For example, sealed wound dressings connected to a vacuum pump can be placed onto an open wound for applying sub-atmospheric pressure to the wound. Such types of negative-pressure applications can be used to draw out fluid from the wound and increase blood flow to a wound area.

<CIT> describes a negative pressure wound closure system and methods for using such a system.

Claimed embodiments relate to systems for use in negative pressure wound therapy (NPWT). A barrier can be configured to be positioned adjacent to wound tissue and prevent or reduce tissue ingrowth from the wound tissue into a pad positioned above the barrier. The barrier can have structures configured to allow for fluid flow yet still inhibit tissue ingrowth. The barrier can be provided separately from existing NPWT dressings and/or used with the existing NPWT dressing to improve performance. The barrier can include irrigation flow channels to allow for simultaneous irrigation and NPWT. The barrier can include one or more other features described herein.

The claimed systems can be used in a method of using a negative pressure wound therapy system that includes providing or receiving a wound dressing comprising a pad and a membrane, wherein the pad is porous, wherein the pad and the membrane are configured to be used for negative pressure wound therapy, providing or receiving a barrier, wherein the barrier is provided separately from the wound dressing, wherein the barrier includes a plurality of perforations, wherein the barrier is configured to be positioned in a wound adjacent to wound tissue, and wherein the barrier is configured to prevent or reduce tissue ingrowth from the wound tissue into the pad, and positioning the barrier in the wound adjacent to the wound tissue. After positioning the barrier in the wound, the pad can be positioned in the wound on top of the barrier in a location that is spaced from the wound tissue by the barrier, the seal can be positioned on top of the pad and wound to at least partially seal the barrier and the pad in the wound, and negative pressure wound therapy can be applied to the wound while the pad and the barrier are positioned in the wound such that fluid is allowed to flow from the wound tissue, through the perforations of the barrier, through the pores of the pad, and through an outlet of the wound dressing.

Implementations can include any, all, or none of the following features. The pad may be an open cell foam sponge, wherein the barrier is an injection molded polymer barrier having complex geometry that is configured to space the open cell foam sponge material from the wound tissue to reduce or prevent tissue ingrowth. The barrier comprises a base layer and a plurality of walls extending from the base layer, wherein a first plurality of the perforations are positioned so as to extend through the base layer at positions between the walls, and wherein a second plurality of perforations are positioned so as to extend through the base layer at positions under the walls. The walls form a repeating polygonal shape, wherein the walls meet at wall intersections, and wherein the second plurality of perforations are positioned under the walls at some but not all of the wall intersections. The walls have a greater height at locations where the walls connect to the base layer than at locations which have the second plurality of perforations positioned under the walls. The barrier comprises a base layer and a plurality of walls extending from the base layer, wherein the walls form a repeating polygonal shape, and wherein posts extend from the base layer at indentations defined between the walls. The barrier comprises a base layer and a plurality of walls extending from top and bottom sides of the base layer, wherein the barrier comprises a plurality of tabs extending from the top side of the base layer, wherein the tabs are configured to be grabbed to pull the barrier out of the wound. The method can further include sucking liquid and exudate through the perforations of the barrier, removing the wound dressing, including removing the pad and the membrane, from the wound, and after removing the wound dressing, removing the barrier from the wound by grabbing one or more tabs extending from the barrier with a tool or one's fingers and pulling. The barrier comprises an injection molded polymer, a radiopaque marker positioned in the injection molded polymer, and a coating positioned on an outer surface of the polymer. The pad is an open cell foam sponge, wherein the barrier is a polymer barrier having complex geometry that is configured to space the wound tissue from the perforations of the barrier, wherein the barrier is integrally formed as a single piece. The barrier is designed to be used with the wound dressing and wherein the wound dressing is designed to be used without the barrier. The barrier has a width that is multiple centimeters long, wherein the barrier has a length that is multiple centimeters long, wherein the barrier has a thickness that is <NUM> to <NUM> thick, and wherein the perforations extending through the barrier have a <NUM> to <NUM> diameter. The plurality of perforations extend through a base layer of the barrier and wherein the barrier defines structure at least partially blocking the perforations. The method can further include cutting the pad to a pad size suitable to be placed in the wound and cutting the barrier to a barrier size suitable to be placed in the wound, wherein the pad and the barrier are cut separately in separate steps.

The claimed systems can be used in a method of using a negative pressure wound therapy system includes positioning a perforated barrier in a wound. After positioning the perforated barrier in the wound, positioning a pad in the wound on top of the perforated barrier, positioning a seal on top of the wound to at least partially seal the perforated barrier and the pad in the wound, and applying negative pressure wound therapy to the wound.

In the claims, a barrier for use in negative pressure wound therapy includes a base layer and top surface structures. The base layer defines a plurality of perforations extending entirely through the base layer, wherein the plurality of perforations are positioned, sized, and configured to allow flow therethrough for negative pressure wound therapy, wherein the base layer defines a top surface and a bottom surface that is configured to be positioned adjacent the surface of a wound. The top surface structures are positioned on the top surface of the base layer, wherein the top surface structures are positioned, sized, and configured to space porous foam material away from the perforations of the base layer when porous foam material is positioned on top of the barrier after the barrier is positioned in the wound.

The barrier has a thickness and a structure configured to create a physical separation between the pad and reduce or prevent tissue ingrowth through the perforations to a porous foam material positioned above the barrier. The top surface structures comprise walls forming a repeating geometric shape, and wherein the walls at least partially cover and block at least some of the perforations through the base layer. The top surface structure comprises walls forming a repeating geometric shape, posts positioned between the walls, and tabs extending upward from the walls. The base layer and the top surface structures comprise a pliable medical grade polymer and further comprising filaments or radiopaque markers embedded in the pliable medical grade polymer. The barrier defines a first set of irrigation channels and a second set of irrigation channels, wherein a plurality of irrigation channels from the second set of irrigation channels branch out from each of the irrigation channels in the first set of irrigation channels. The barrier defines an inlet along an edge of the barrier, wherein the inlet is fluidly connected to the first set of irrigation channels and the second set of irrigation channels with the first set of irrigation channels positioned between the inlet and the second set of irrigation channels. This inlet can extend normal to the surface of the barrier, to pass through and overlying pad and connect to an irrigation source. The barrier defines an inlet at a middle portion of the barrier, wherein the inlet is fluidly connected to the first set of irrigation channels and the second set of irrigation channels with the first set of irrigation channels positioned between the inlet and the second set of irrigation channels.

In a related, illustrative negative pressure wound therapy system, the system includes a wound dressing comprising a membrane, a pad comprising a porous foam sponge configured to be positioned under the membrane, and a barrier configured to be positioned under the pad. The barrier includes a plurality of perforations, wherein the pad and the barrier are configured to be positioned together in a wound with the barrier positioned adjacent to wound tissue and the pad positioned between the barrier and the membrane, and wherein the barrier is configured to prevent or reduce tissue ingrowth from the wound tissue into the pad.

This related, illustrative negative pressure wound therapy system can include any, all, or none of the following features. The pad is an open cell foam sponge, wherein the barrier is an injection molded or otherwise fabricated polymer barrier having complex geometry that is configured to space the open cell foam sponge material from the wound tissue to prevent tissue ingrowth. The barrier comprises a base layer and a plurality of walls extending from the base layer, wherein a first plurality of the perforations are positioned so as to extend through the base layer at positions between the walls, and wherein a second plurality of perforations are positioned so as to extend through the base layer at positions under the walls. The barrier comprises a base layer and a plurality of walls extending from the base layer, wherein the walls form a repeating polygonal shape, and wherein posts extend from the base layer at indentations defined between the walls. The barrier comprises an injection molded polymer, a radiopaque marker positioned in the injection molded polymer, and a coating positioned on an outer surface of the polymer. The plurality of perforations extend through a base layer of the barrier and the barrier defines structure at least partially blocking the perforations. The barrier is physically attached to the pad so as to be sold and delivered together. The barrier is attachable to the pad via one or more fasteners. The barrier defines a first set of irrigation channels and a second set of irrigation channels, wherein a plurality of irrigation channels from the second set of irrigation channels branch out from each of the irrigation channels in the first set of irrigation channels.

In a related, illustrative barrier for use in negative pressure wound therapy and wound irrigation, the barrier includes a base layer defining a plurality of perforations through the base layer, wherein the plurality of perforations are positioned, sized, and configured to allow flow therethrough for negative pressure wound therapy, wherein the base layer defines a top surface and a bottom surface. The barrier defines a first set of irrigation channels and a second set of irrigation channels, wherein a plurality of irrigation channels from the second set of irrigation channels branch out from each of the irrigation channels in the first set of irrigation channels. The perforations of the barrier are sized, positioned, and configured to allow for suction flow from a wound surface positioned under the bottom surface of the base layer, through the perforations, and to an area above the top surface of the base layer. The first and second sets of irrigation channels of the barrier are sized, positioned, and configured to allow for irrigation through the first and second sets of irrigation channels to the wound surface. The barrier is configured to allow for the suction and the irrigation simultaneously.

This related, illustrative barrier can include any, all, or none of the following features. The barrier defines an inlet along an edge of the barrier, wherein the inlet is fluidly connected to the first set of irrigation channels and the second set of irrigation channels with the first set of irrigation channels positioned between the inlet and the second set of irrigation channels. The barrier defines an additional irrigation channel extending from the inlet to the second set of irrigation channels so as to fluidly connect the inlet to the first set of irrigation channels. The barrier defines an inlet at a middle portion of the barrier, wherein the inlet is fluidly connected to the first set of irrigation channels and the second set of irrigation channels with the first set of irrigation channels positioned between the inlet and the second set of irrigation channels. The inlet tube is of sufficient length to more than traverse the full thickness of the pad overlying the barrier, whether the pad is placed piece-meal as a separate unit during dressing application or is manufactured to be fixedly attached to the barrier as a single unit. The inlet tube will also penetrate the sealing membrane after complete application of the dressing and then connect to an irrigation supply tubing which communicates the irrigant from the irrigation source to the dressing. The point at which the inlet tube will penetrate or cross the sealing membrane can be further improved, by including an integrated flat manifold, which acts to hold the inlet tubing, generally normal to the dressing in a central location, and further provide a flat surface where the sealing membrane can be adhered at application of the dressing to the body. This flat surface allows for easier application of the sealing membrane encouraging an airtight seal for the dressing, which is a preferred state. This manifold can also include a separate attachment point or coupling for the suction tubing that extends from the regulated vacuum source to the dressing. The barrier further comprises top surface structures positioned on the top surface of the base layer, wherein the top surface structures are positioned, sized, and configured to space porous foam material away from the perforations of the base layer when porous foam material is positioned on top of the barrier after the barrier is positioned in the wound. The second set of irrigation channels terminate at outlets that are positioned at the bottom surface of the barrier, wherein some of the outlets are positioned proximate a perimeter of the barrier with other outlets positioned closer to a center of the barrier. A tubular extension extends from the inlet in a direction that is generally normal to the barrier. A system includes the barrier, a wound dressing comprising a pad with the barrier fixedly attached to the pad, and a tubular extension that extends from the irrigation inlet of the barrier through the pad to an end that is configured to be connected to an irrigation source. The tubular extension is configured to allow for simultaneous irrigation and negative pressure. The tubular extension is configured to allow for alternating irrigation and negative pressure. A manifold is fluidically connected to the tubular extension. The manifold is positioned adjacent the pad at a location where the tubular extension extends through the pad. The manifold defines a suction inlet configured to connect to suction tubing.

In a related, illustrative system, the system includes a wound dressing comprising a membrane, a pad, and a barrier. The pad comprises a porous foam sponge configured to be positioned under the membrane. The pad comprises a pad bottom, a pad top, and pad sides. The barrier is wrapped around the pad, wherein the barrier is configured to prevent or reduce tissue ingrowth from the wound tissue into the pad.

This related, illustrative system can include any, all, or none of the following features. The barrier is wrapped around a pad bottom and at least part of the pad sides. The barrier is wrapped around a circumference of the pad. The barrier is wrapped completely around a circumference of the pad. The barrier and the pad are sized and shaped to be used in fistulous or tunneled wounds that have a long narrow geometry. The pad comprises a sponge. The barrier comprised medical grade polymer The barrier defines perforations. The pad and barrier combine to form a shape that is long and narrow at a distal end and wider and flatter at a proximal end. The barrier is substantially nail shaped. The barrier is substantially funnel shaped. The barrier is substantially kettle shaped. The barrier comprises a head portion and a cylinder portion The cylinder portion is perforated. The cylinder portion is wrapped around the pad sides. The wound dressing comprises one or more irrigation flow paths configured to deliver irrigant to the barrier. The wound dressing comprised one or more suction flow paths configured to provide negative pressure at the dressing. The one or more irrigation flow paths are independent from the one or more suction flow paths. A method of using the wound dressing includes cutting a distal end of the wound dressing so as to cut both the pad and the barrier. The pad can be moved at least partially out of the distal end of the wound dressing. A portion of the pad that was pulled out of the distal end of the wound dressing can be cut. The pad can be moved back into the wound dressing. The pad can be positioned inside the barrier such that the pad is spaced inward from a distal opening of the barrier by a gap. A distal opening of the barrier can be closed after the barrier has been cut. A distal opening of the barrier can be sutured after the barrier has been cut.

Other features, aspects and potential advantages will be apparent from the accompanying description and figures.

The technology disclosed herein generally relates to a system, device and method for negative pressure wound therapy (NPWT). A dressing for NPWT can include a foam sponge pad or wound filler that is placed in the wound and a sealing membrane that covers the wound and the foam sponge pad. A hose can connect the dressing to a vacuum source to apply regulated NPWT to the wound to beneficially facilitate healing of the wound. However, current systems can result in undesirable tissue ingrowth into pores of the foam sponge pad within <NUM> to <NUM> days. This ingrowth not only limits the potential safe duration of wear, it also leads to increased pain and wound tissue trauma when the dressing is changed. A barrier can be positioned under the foam sponge pad or wound filler to separate the foam sponge pad away from the wound and to prevent or restrict tissue ingrowth during NPWT. The barrier can be made of a flexible medical grade polymer material and can have complex geometry that can allow flow of fluid and exudate through the barrier during NPWT yet still prevent or restrict the wound tissue from growing into the foam sponge pad or wound filler. The barrier can be used with existing wound dressings that are designed for use without such a barrier, or can be part of a wound dressing where the barrier is attached to the foam sponge pad or other type of wound filler (i.e. gauze). In this scenario, during the manufacturing of the sponge or wound filler, a similar barrier construct could be attached to the sponge pad/wound filler in order to substantially prevent ingrowth. The barrier could also replace the sponge or wound filler completely. Replacement can be performed at the manufacturing stage by the product manufacturer or at the application stage by the clinician.

Tissue ingrowth is undesirable because it has several consequences. When a dressing is removed after tissue ingrowth into the dressing has occurred, this can result in the tearing of healthy tissue away from the wound surface. This is particularly problematic when the wound exposes critical or delicate structures, such as blood vessels, nerves or visceral organs. This phenomenon results in significant pain with dressing changes and traumatizes the wound tissues, which can be adverse to the healing process. For this reason, dressing changes are required frequently to prevent too much ingrowth, usually within <NUM> or <NUM> days, therefore a barrier that prevents or reduces in-growth could allow for extended duration of wear which is a unique clinical benefit of some aspects of this invention. Tissue ingrowth can also result in tearing of the sponge or wound filler resulting in foreign matter being left behind in the wound. These areas of foreign matter can create inflammatory responses, heterotopic ossification and/or infections.

<FIG> shows a schematic view of a negative pressure wound therapy (NPWT) system <NUM> and a patient <NUM> having a wound (not shown in <FIG>). The NPWT system <NUM> includes an electronic vacuum regulator (EVR) <NUM>, a canister <NUM>, a tubing system <NUM>, and a wound dressing <NUM>. NPWT can occur in a hospital setting or outside of the hospital with chronic wounds.

The EVR <NUM> can include a controller (including one or more processors and memory) and a flow rate meter having one or more valves and sensors to measure and control the flow rate of liquid through the EVR <NUM> and/or the amount of negative pressure applied. In some embodiments, the EVR <NUM> can include a pump or other device configured to produce negative pressure. In some embodiments, the EVR <NUM> can be connected to a pump or other device configured to produce negative pressure, such as a wall vacuum source or a dedicated vacuum source.

The wound dressing <NUM> can be configured to cover and substantially seal a wound of the patient <NUM>. The tubing system <NUM> can include one or more hoses to connect the wound dressing <NUM>, the canister <NUM>, and the EVR <NUM> to apply negative pressure (a vacuum) to the wound of the patient <NUM>. The canister <NUM> can collect liquid removed from the wound of the patient <NUM>.

In some embodiments, the NWPT system <NUM> can be configured differently than as illustrated. For example, one or more of the EVR <NUM>, the canister <NUM>, the tubing system <NUM>, and the wound dressing <NUM> can be shaped and positioned differently than as illustrated. Additionally, one or more components can be added, replaced, or removed from the NWPT system <NUM>. For example, the canister <NUM> can be replaced with a collection bag.

<FIG> is a schematic view of the NWPT system <NUM>, including the EVR <NUM>, the tubing system <NUM>, and the wound dressing <NUM> (the canister <NUM> is omitted from <FIG>).

A portion of the patient <NUM> is shown including a wound <NUM>. In the illustrated example, the wound <NUM> is a relatively deep wound into the flesh of the patient <NUM>. The wound <NUM> can be deep enough to extend through skin tissue <NUM>, through fat tissue <NUM>, and into muscle tissue or visceral spaces <NUM> of the patient <NUM>. In other examples, the wound <NUM> can be deeper or less deep depending on the injury to the patient <NUM>.

In the illustrated embodiment, the wound dressing <NUM> includes a tubing connector <NUM>, a membrane <NUM>, and a pad <NUM>, such as a foam sponge pad, a gauze pad, or other type of wound filler. The pad <NUM> can be an open cell foam pad (commonly called a sponge) that is cut to size and placed in the wound <NUM>. The membrane <NUM> can be a relatively thin membrane configured to substantially seal the wound <NUM>. The tubing connector <NUM> can connect to the tubing system and extend through the membrane <NUM> to allow for the EVR <NUM> to apply negative pressure to the wound <NUM>. The pad <NUM> can be porous to allow flow of liquid and gas between the tubing connector <NUM> and a surface of the wound <NUM>. The membrane <NUM> can have an adhesive positioned around a perimeter of the membrane <NUM> that is configured to stick the membrane <NUM> to the patient <NUM> and seal the wound <NUM> well enough that the EVR <NUM> can suitably apply negative pressure to the wound <NUM> to promote new tissue growth.

In claimed embodiments, an additional barrier <NUM> is added under the pad <NUM>. The barrier <NUM> can be a separation layer that is positioned between the pad <NUM> and the surface of the wound <NUM> to space the pad <NUM> from the surface of the wound <NUM> and prevent or reduce tissue in-growth into pores of the pad <NUM>.

In other cases outside the scope of the claims, the tubing connector <NUM>, the membrane <NUM>, and the pad <NUM> can be part of a wound dressing <NUM> for a negative pressure wound therapy system that is intended to be delivered without the barrier <NUM> and is configured for use without the barrier <NUM>. In such situations, the wound dressing <NUM> can be intended to be used with the pad <NUM> placed into the wound <NUM> and covered by the membrane <NUM> without placing the barrier <NUM> under the pad <NUM>. In such situations, NPWT can be performed without the barrier <NUM>, however, doing so can allow for tissue ingrowth into pores of the pad <NUM>. Therefore, the barrier <NUM> can be provided separately as an additional structure to improve upon an existing wound dressing <NUM> where the pad <NUM> is a porous foam material that is susceptible to tissue ingrowth.

The barrier can also be placed to provide protection from desiccation or drying out of susceptible structures such as tendons, nerves, blood vessels, and/or bone. The barrier can be coated with a lubricant such as Vaseline or even antimicrobials such as antibiotics, silver compounds or other materials such as growth factors or other chemicals or medications to promote tissue healing and/or prevent infection.

The barrier <NUM> can be added as an additional structure in order to prevent or reduce in-growth of tissue (e.g. the muscle tissue or visceral organs <NUM>) into pores of the pad <NUM>. The barrier <NUM> can space the pad <NUM> from one or more tissues in order prevent or reduce contact with those tissues. In the illustrated embodiment, the barrier <NUM> is positioned under the pad <NUM> and also wrapped at least partially around sides of the pad <NUM> to space the pad <NUM> from tissue. In the illustrated embodiment, the barrier <NUM> is positioned between the pad <NUM> and the muscle tissue <NUM>, but not necessarily between the pad <NUM> and the fat tissue <NUM> (the barrier <NUM> is shown adjacent to only part of the fat tissue <NUM>) or the skin tissue <NUM>. Such a configuration can be used where it is desired to prevent ingrowth from the muscle tissue <NUM> while ingrowth by the fat tissue <NUM> and the skin tissue <NUM> is deemed to be less of a concern. In other embodiments, the barrier <NUM> can be larger or smaller and placed to cover more (e.g. covering all or part of each of the skin tissue <NUM>, the fat tissue <NUM>, and/or the muscle tissue <NUM>) or fewer tissues as suitable for the application.

In other embodiments, not illustrated herein, the barrier <NUM> can be wrapped fully or partially around the pad <NUM>, thereby fully or partially enclosing the pad <NUM>. This particular embodiment would be most useful for deep tracts or tunnels in the wound, in which wound filler is often placed to apply NPWT and prevent loculation. These specific embodiments can have preferred shapes (i.e. cylindrical or rectangular) and dimensions for commonly treated deep wound tracts or tunnels. The advantage of these embodiments over traditional methods, is that the barrier can serve its innovative function of physically separating the wound filler from the wound tissue to prevent or reduce ingrowth in a more circumferential fashion in parts of the wound that have more than just a single planar surface that needs to heal.

As explained above, the barrier <NUM> can be a structure that is entirely separate from the pad <NUM>, and it can be sold and provided separately for use with a version of the wound dressing <NUM> that was intended to be used without the barrier <NUM>. In alternative embodiments, the barrier <NUM> can be attached to the pad <NUM> and can be sold and delivered together (see, for example, the dressings <NUM>, <NUM>, and <NUM> described below with respect to <FIG>). In further alternative embodiments, the barrier <NUM> can be provided separately from the pad <NUM>, yet be configured to be attached to the pad <NUM> such as by using one or more fasteners at the time of application of the dressing.

The barrier <NUM> is a porous barrier configured to reduce or prevent tissue ingrowth. In some embodiments, the barrier <NUM> can be shaped and configured as illustrated in <FIG>. In other embodiments, the barrier <NUM> can have different shapes and features as suitable for the application. Multiple layers of different geometric shapes such as circles, hexagons, polygons, screens, etc. can be used to create pathways for suction transmission and fluid or gas passage while still creating a barrier between the solid but compressible sponge or wound filler and the wound. These layers can be separate or manufactured as a single unit. Perforations in the barrier can allow flow both parallel and perpendicular to the surface of the wound to improve or optimize NPWT functionality.

Current sponges or other wound fillers are open cell structures that allow for pieces or parts of the sponge to be left behind in the wound. Likewise, when gauze is used as a wound filler, it can become unraveled also resulting in pieces being left in the wound. The barrier can be created to reduce this by ensuring a closed cell structure. A barrier that is devoid of surface pores that are in the <NUM>-<NUM> micron range for example, can prevent or reduce in-growth into the dressing. Avoiding foreign material being left inside the wound is optimal.

<FIG> is a perspective view of the barrier <NUM>. <FIG> is a top plan view of the barrier <NUM>. <FIG> is an enlarged perspective view of a portion of the barrier <NUM>. The barrier <NUM> can include complex geometry configured to space tissue away from a porous pad <NUM> to reduce or prevent tissue ingrowth. Therefore, the barrier <NUM> provides a physical separation between the wound and the in-growth inducing surface of the wound filler. The barrier <NUM> includes a base layer <NUM> and structure extending from the base layer <NUM>, such as walls <NUM> and posts <NUM>.

The walls <NUM> can define a repeating polygonal shape, such as the repeating hexagonal shape illustrated in <FIG>. In other embodiments, the walls <NUM> can define a different repeating polygonal shape than as illustrated. In other embodiments, the walls <NUM> can define a different non-polygonal repeating shape, such as repeating circles. In other embodiments, the walls <NUM> can define different shapes as suitable for the application.

The walls <NUM> and the posts <NUM> can extend substantially normally from the base layer <NUM> to impart thickness to the barrier <NUM>. The posts <NUM> can be positioned substantially centrally in one, more than one, or all of spaces (or indentations) defined by the walls <NUM>. The posts <NUM> can provide an offset to help keep tissue (i.e. the muscle tissue <NUM>) or material (i.e. material of the pad <NUM>) out of the spaces defined by the walls <NUM>. In other embodiments, the posts <NUM> can be omitted if the barrier is shaped and configured to suitably operate without the posts <NUM>.

The base layer <NUM> of the barrier <NUM> can define a plurality of perforations (or pores) <NUM> extending through the base layer <NUM>. The base layer <NUM> can define one or more perforations <NUM> extending through the base layer <NUM> in each of the spaces defined by the walls <NUM> and can define perforations <NUM> extending through the base layer <NUM> at positions under the walls <NUM>. In some embodiments, the perforations <NUM> are the only passages extending entirely through the base layer <NUM>.

As shown in <FIG>, the base layer <NUM> includes three perforations <NUM> in each of the hexagonal spaces (or indentations) defined between the walls <NUM>. In other embodiments, more or fewer than three perforations <NUM> can be positioned in each of the spaces defined between the walls <NUM>.

As shown in <FIG>, the base layer <NUM> also includes one perforation <NUM> extending through the base layer <NUM> at some of the intersections of the walls <NUM>. As shown, the base layer <NUM> includes perforations <NUM> under roughly half of the intersections of the walls <NUM>. In other embodiments, the base layer <NUM> can include more or fewer perforations <NUM> positioned under the walls <NUM> than as illustrated.

As best illustrated in <FIG>, the walls <NUM> can have a smaller height at portions 132A of the walls <NUM> that are positioned over perforations <NUM> and can have a taller height at portions 132B of the walls <NUM> that are connected to the base layer <NUM>. This can allow for increased flow through perforations <NUM> that are positioned under the walls <NUM>. This different in wall height also forms passages through the walls <NUM> that can facilitate flow laterally across the barrier <NUM>.

In some embodiments, the barrier <NUM> can include one or more tabs <NUM> extending away from the base layer <NUM>. The tabs <NUM> can be sized, shaped, and configured to allow for a user (e.g. a doctor or other medical provider) to pull on the tabs <NUM> to remove the barrier <NUM> from the wound <NUM>. The tabs <NUM> can have a strength that is suitable to withstand the force of pulling on the tabs <NUM> without tearing after the barrier <NUM> has been left in the wound <NUM> for an extended period (e.g. several hours or several days). Additional embodiments include suture or wire that can extend outside the barrier <NUM> to enable or facilitate removal.

The base layer <NUM> can be the bottom-most layer of the barrier <NUM> and is configured for a bottom surface <NUM> of the base layer <NUM> to be positioned adjacent the surface of the wound <NUM>. The structure extending up from a top surface <NUM> of the base layer (e.g. the walls <NUM> and the posts <NUM>) can be positioned adjacent the porous material of the pad <NUM>. The barrier <NUM> can space the pad <NUM> away from the wound <NUM> so as to prevent or reduce tissue ingrowth into the pad <NUM> without additional structure extending from a bottom side of the base layer <NUM>. In some embodiments, the barrier <NUM> can be manufactured as an integral component of the sponge pad or wound filler <NUM>, such that the two elements are not separate, but one. Such a composite improved NPWT dressing could possess most commonly an open-cell foam sponge superficial surface (i.e. facing away from the wound), whose primary purpose would be to facilitate transmission of negative pressure to the wound and evacuation of wound fluids from the wound <NUM> surface. Then a barrier layer can be fixedly attached on a wound-facing surface of this composite dressing. Such a barrier layer can serve the same purpose as the barrier <NUM> does in other embodiments in which the barrier <NUM> is an independent and separate piece. Such a barrier would be a physical barrier intended to prevent or reduce tissue in-growth into the open-cell foam sponge or other wound filler material. In this way, this embodiment would not be an add on to current NPWT dressings, but rather a uniquely new NPWT dressing with enhanced capability over and above the current art.

In other embodiments, the barrier <NUM> can have structure extending from both of the top and bottom surfaces <NUM> and <NUM> of the base layer <NUM>. For example, the barrier <NUM> can have walls <NUM> and posts <NUM> extending from the bottom surface <NUM> that are substantially a mirror image to the walls <NUM> and the posts <NUM> extending from the top surface <NUM> (except that the tabs <NUM> can be omitted). Alternatively, the barrier <NUM> can have structure extending from the bottom surface <NUM> of the base layer <NUM> that is different than the structure extending from the top surface <NUM> of the base layer <NUM>. Structure that extends from the top surface <NUM> can be sized, shaped, and configured to interface with the pad <NUM>. Structure that extends from the bottom surface <NUM> can be sized, shaped, and configured to interface with the muscle tissue <NUM> or some other tissue of the patient <NUM> to prevent or resist the muscle tissue <NUM> from clogging the pores <NUM> when the muscle tissue <NUM> grows during the negative pressure wound therapy.

As shown in <FIG>, the walls <NUM> can at least partially block at least some of the perforations <NUM> when viewed from the top (see, e.g., <FIG>). In some embodiments, the barrier <NUM> includes structure (e.g. the walls <NUM>) that at least partially block all of the perforations <NUM> that extend through the base layer <NUM>. In such embodiments, all (or substantially all) of the perforations <NUM> are at least partially blocked to prevent or reduce tissue growth from extending through the barrier <NUM> to pores of the pad <NUM>.

The barrier <NUM> can be a one piece structure with complex geometry. Accordingly, the base layer <NUM>, the walls <NUM>, the posts <NUM>, and the tabs <NUM> can be integrally formed as a single construct. Alternative designs can allow for the barrier <NUM> to have multiple layers and allow for removal of some layers to decrease the height of the barrier by the treating provider at the time of dressing application. The barrier <NUM> can be integrally formed by injection molding via a pliable medical grade polymer. For example, the barrier <NUM> can be made of silicon or polyurethane. In other embodiments, the barrier <NUM> can be made of polydioxanone, or another material that is able to dissolve if left implanted in the patient <NUM> for many days.

The barrier <NUM> can be constructed of biodegradable material and left in the wound <NUM> permanently. The barrier <NUM> can be clear, colored, or tinted to allow for easy identification within the wound <NUM> in order to prevent it from being left in the wound <NUM>, for versions of the barrier <NUM> that are not biodegradable. A radiographic marker can be included in the barrier <NUM> to allow for identification by radiograph, as a means of preventing unintended retention of a dressing in a wound.

In some embodiments, the barrier <NUM> can be made of a transparent or translucent material. This can allow for better visualization of the wound <NUM> under the barrier <NUM>. The barrier <NUM> can also be tinted (such as tinted purple, green, and/or blue) to increase visibility in the wound <NUM> so as to avoid or reduce the risk of the barrier <NUM> being undesirably left in the wound <NUM>. In some embodiments, the barrier <NUM> can be both tinted as well as transparent or translucent. In some embodiments, the tabs <NUM> (or other removal handles) can be colored and some or all of other portions of the barrier <NUM> can be clear and not colored.

In some embodiments, the barrier <NUM> can be formed of a material and can be sized and shaped to be both somewhat pliable and somewhat shape-retaining. For example, the barrier <NUM> can be pliable enough to bend to conform to a shape of a wound and/or to wrap at least partially around a sponge or other pad <NUM>, such as shown schematically in <FIG>. Additionally, the barrier <NUM> can be rigid enough such that the structure (e.g. the walls <NUM> and posts <NUM>) at least partially retain its shape when placed in the wound <NUM> under the pad <NUM> and negative pressure is applied to allow for flow through the barrier <NUM>.

In some embodiments, the barrier <NUM> can be configured to be cut. Doctors or other medical personnel can cut the barrier <NUM> to shape so as to fit in the wound <NUM> depending on the shape of the wound <NUM>. In some of such embodiments, the barrier <NUM> can also be rigid enough to be held in one hand and cut with the other hand without the barrier <NUM> sagging undesirably limp during the cutting process.

The barrier <NUM> can be sized to be relatively long and wide as viewed from the top (see <FIG>) and to have a relatively thin thickness (or height) as viewed on-edge. For example, the barrier <NUM> can have a length and width that are each several centimeters long and a thickness that is about <NUM> to <NUM> thick. In embodiments where the barrier <NUM> includes the tabs <NUM>, the barrier <NUM> can have a thickness of <NUM> to <NUM> not including the tabs <NUM> such that the tabs <NUM> effectively increase the thickness of the barrier <NUM> to more than <NUM> to <NUM>.

The barrier <NUM> can have a relatively high tensile strength so as to resist ripping when in tension.

The perforations <NUM> can be sized large enough to allow for flow through the barrier <NUM> such that the NPWT system <NUM> functions effectively to apply negative pressure to the wound <NUM> below the barrier <NUM>. For example, the perforations <NUM> can each have a diameter of about <NUM> to <NUM>. The perforations <NUM> of the barrier <NUM> can be sized and shaped to allow for the sucking of liquid and exudate through the perforations <NUM> without clogging the perforations <NUM> (or with reduced clogging of the perforations <NUM>).

The walls <NUM> and/or the posts <NUM> can have a thickness (when viewed from the top as in <FIG>) that is small enough to allow the barrier <NUM> to be flexible and that is large enough to at least partially resist compression when the barrier <NUM> is placed under the pad <NUM> and negative pressure is applied. For example, the walls <NUM> and/or the posts <NUM> can have a thickness (when viewed from the top as in <FIG>) of between <NUM> and <NUM>.

In some embodiments, the barrier <NUM> can include radiopaque material. Radiopaque material can help ensure that the barrier <NUM> is visible during x-ray imaging, which, can allow medical professionals to remove the barrier <NUM> from the patient <NUM> in the event that the barrier <NUM> is accidentally left inside the patent after the barrier <NUM> was supposed to be removed. For example, the barrier <NUM> can include one or more radiopaque markers such as thin diameter wires (not shown) embedded within flexible, medical-grade polymer material that forms the barrier <NUM>. In some embodiments, a radiopaque thin diameter wire can be positioned in the barrier <NUM> at the one or more tabs <NUM> to both reinforce the tabs <NUM> and to help confirm removal using radiography. The wire or suture can also be used as "rebar" to reinforce the tensile strength of the barrier <NUM> and resist tearing. The wire or suture in this embodiment would typically be manufactured to lay within the walls of the barrier <NUM>.

In some embodiments, the barrier <NUM> can include a coating. For example, the barrier <NUM> can be coated with a lubricant. Coating with a lubricant can be beneficial in situations, such as, when used in wounds with exposed bone or tendon to help prevent (or resist) the bone or tendon from drying out. Alternatively or in addition, the barrier <NUM> can be coated with a bacteriostatic agent that is configured to stop or slow the reproduction of bacteria. Alternatively or in addition, the barrier <NUM> can be coated with an antibiotic coating. Moreover, the barrier <NUM> can be coated with another coating that is deemed suitable for the application.

In some embodiments, the barrier <NUM> can include irrigation flow channels (e.g. see the irrigation channels of <FIG>, <FIG>, and <FIG>) extending through the barrier <NUM>. For example, irrigation flow channels can extend through the barrier <NUM> along a main trunk line flowing through a middle portion of the barrier <NUM> and with branch lines extending out from the trunk line. Accordingly, such a barrier <NUM> can allow for irrigation to be supplied to the wound <NUM> through the flow channels and be suctioned away from the wound <NUM> through the perforations <NUM> of the barrier <NUM> and through the pores of the foam of the pad <NUM>. This type of dressing can support either simultaneous or alternating periods of irrigation and suction. If alternating between suction and irrigation, there can be periods of dwell time between periods spent irrigating or suctioning the wound. If and when trimming of the barrier <NUM> is desired for the barrier <NUM> having irrigation flow channels, the barrier <NUM> could be trimmed in areas where there are branch lines while maintaining the inlet to the trunk line untrimmed. In embodiments that do not require irrigation, the barrier <NUM> need not include flow channels.

<FIG> is a top view of a barrier <NUM> having irrigation channels <NUM>, <NUM>, and <NUM>. The irrigation channel <NUM> can be a main trunk line from which the irrigation channels <NUM> branch off. The irrigation channels <NUM> can, in turn, branch off the irrigation channels <NUM>. Accordingly, the irrigation channels <NUM>, <NUM>, and <NUM> can be oriented similar to the veins in a leaf where a central tube (e.g. the irrigation channel <NUM>) branches into additional tubes (e.g. the irrigation channels <NUM> and/or <NUM>) to cover the entire surface. This orientation can allow a tube <NUM> to enter from a side of the barrier <NUM> to supply irrigant to the barrier <NUM>. In other embodiments, the tube can be positioned substantially normal and central to the non-wound facing surface of the barrier and the irrigation channels can extend radially from this tube. This tube can be long enough to extend through or more than through the common thickness of a wound filler, like foam sponge. In some embodiments, a clamp <NUM> can be included on the tube <NUM> to clamp down and seal or restrict flow through the tube <NUM>. In some embodiments, the tube <NUM> can include a connector <NUM> for connecting to additional tubing (e.g. to the tubing system <NUM> described above with respect to <FIG> and <FIG>). In some embodiments, the barrier <NUM> can be substantially similar to the barrier <NUM> described above except for the addition of the irrigation channels <NUM>, <NUM>, and <NUM>. In such embodiments, the barrier <NUM> can be used to supply irrigant to the wound (via the irrigation channels <NUM>, <NUM>, and <NUM>), and simultaneously allow for negative pressure wound therapy, with liquid and exudate sucked through the perforations <NUM> (not shown in <FIG>). By allowing for negative pressure wound therapy simultaneously with irrigation, this can reduce or eliminate the need for a dwell time between irrigation and negative pressure wound therapy. In various embodiments, the barrier <NUM> can have one or more different structures as suitable for the application as a barrier having irrigation channels.

<FIG> and <FIG> are top and side views of a barrier <NUM> having irrigation channels <NUM> and <NUM>. The irrigation channels <NUM> form multiple main trunk lines from which the irrigation channels <NUM> branch off. A tube <NUM> connects to the barrier <NUM> at a middle portion <NUM>, and the irrigation channels <NUM> extend radially outward from the middle portion <NUM>. Accordingly, this alternate orientation of the barrier <NUM> would allow for the tube <NUM> to be run outside of the barrier <NUM> (above it) and allow radial tubes (the irrigation channels <NUM>) to be designed to take the irrigation towards a periphery of the barrier <NUM>. The irrigation channels <NUM> can terminate at outlets <NUM> that are positioned on a bottom surface of the barrier <NUM> and/or at the periphery of the barrier <NUM>. Some of the outlets <NUM> can be positioned proximate a perimeter of the barrier <NUM> so as to irrigate tissue near the perimeter of the barrier <NUM> and some of the outlets <NUM> can be positioned closer to a center of the barrier <NUM> so as to irrigate tissue near the center of the barrier <NUM>. In alternative embodiments, the barrier <NUM> can have irrigation channels that are different than those illustrated.

The barriers <NUM> and <NUM> can have features (e.g. walls <NUM>, posts <NUM>, and/or perforations <NUM>) and uses that are the same or similar to those described herein for the barrier <NUM>. For example, one of the barriers <NUM> or <NUM> can be used in a manner similar to the barrier <NUM> as described above for <FIG>, with the barrier <NUM> or <NUM> added as an additional structure in order to prevent or reduce in-growth of tissue (e.g. the muscle tissue or visceral organs <NUM>) into pores of the pad <NUM>. The barrier <NUM> or <NUM> can be a structure that is entirely separate from the pad <NUM>, and it can be sold and provided separately for use with a version of the wound dressing <NUM> that was intended to be used without the barrier <NUM> or <NUM>. In alternative embodiments, the barrier <NUM> or <NUM> can be attached to the pad <NUM> and can be sold and delivered together (see, for example, the dressings <NUM>, <NUM>, and <NUM> described below with respect to <FIG>). In further alternative embodiments, the barrier <NUM> and <NUM> can be provided separately from the pad <NUM>, yet be configured to be attached to the pad <NUM> such as by using one or more fasteners at the time of application of the dressing.

In some embodiments, the barriers <NUM> and <NUM> can be configured to be trimmed (e.g. via scissors) to substantially match the size of the wound <NUM> and still function to supply irrigant to the surface of the wound <NUM>. For example for the barrier <NUM>, the tube <NUM> is attached to the barrier <NUM> along one edge. Accordingly, the barrier <NUM> can be trimmed down to size by trimming the other three edges while maintaining the structural integrity of the connection between the tube <NUM> and the barrier <NUM>. During trimming, one or more of the channels <NUM> and <NUM> can be cut and yet the barrier <NUM> can still function to supply irrigant to the surface of the wound <NUM> through those portions of the channels <NUM> and <NUM> that remain.

Additionally, for the barrier <NUM>, the tube <NUM> is attached to the barrier <NUM> at the middle portion <NUM>. Accordingly, the barrier <NUM> can be trimmed down to size by trimming any of the four edges while maintaining the structural integrity of the connection between the tube <NUM> and the barrier <NUM> at the middle portion <NUM>. During trimming, one or more of the channels <NUM> and <NUM> can be cut and yet the barrier <NUM> can still function to supply irrigant to the surface of the wound <NUM> through those portions of the channels <NUM> and <NUM> that remain.

In some embodiments, the barrier <NUM> (as well as the barriers <NUM> and <NUM>) can include filaments that act to reinforce the integrity of the barrier <NUM> in a manner that is similar to rebar in concrete. Such filaments can be in the form of suture material, a metal, a fabric, and/or a stronger polymer. The filaments can be high tensile material that helps resist or prevent portions of the barrier <NUM> being fragmented and retained in the wound <NUM>.

The filaments can be in a central portion of the barrier <NUM> in plane with the barrier <NUM>, such that the filaments are in-line to transect or follow the margins of the perforations <NUM>. The filaments can also be in a random pattern to allow for improved tensile strength without being too bulky. In some embodiments, the filaments can be in the form of a mesh layer that is embedded in the barrier <NUM> prior to the barrier <NUM> being perforated. A perforating tool can cut a hole in the barrier <NUM>, and also in the mesh filaments imbedded in the barrier <NUM>. Thus, the mesh filaments can optionally be positioned in order to prevent or reduce overlap across the perforations <NUM>.

These filaments can optionally traverse the perforations <NUM>. If the filaments do traverse the perforations <NUM>, the filaments can serve as a sieve to prevent tissue ingrowth yet permit the evacuation of wound fluids.

In alternative embodiments, the barrier <NUM> can be formed as a flat woven mesh layer or a three dimensional mesh structure (such as a pot scrubber or loofah) dipped or coated in silicone or similar material that is bio-compatible/inert. Such a mesh structure could also be similar to a honeycomb type structure. The mesh structure can offer tensile strength and compressibility. The mesh structure can be constructed of suture, metal, polymer, or fabric material. The mesh structure can form a core material that offers tensile strength and that is coated to prevent or reduce tissue ingrowth. Constructing the barrier <NUM> in this manner can allow for a compressible structure with significant fluid pathways to allow irrigation passage as well as transmit negative pressure. In some embodiments, the barrier <NUM> can have a structure that is constructed of transparent coating over thin filaments (such as a PDS, proline, monocryl, or woven polyester such as ethibond, fiberwire, or vycryl). The barrier <NUM> can be made of non-dissolvable or dissolvable material. In another embodiment, the barrier <NUM> can include a dissolvable polyglycolate material. In another embodiment, the barrier <NUM> can include collagen based materials to create structural support but still allow a fully dissolvable barrier <NUM>.

In some embodiments, the barrier <NUM> can also be used with any suitable system as a sponge, pad, or wound filler replacement. By removing the pad <NUM> (or any other wound filler) and using the barrier <NUM>, the clinician can see the wound <NUM> assuming the barrier <NUM> is constructed of a clear material. The tabs <NUM> can be trimmed to allow for easier sealing over the barrier <NUM>. The barrier <NUM> can be used with any suitable system that incorporates a sealing layer102 and suction tubing <NUM>.

<FIG> is an example method <NUM> of using the NPWT system <NUM>. At step <NUM>, the wound <NUM> of the patient <NUM> is prepared. This can include cleaning the wound <NUM>, removing necrotic tissue, and/or other procedures deemed necessary or desirable. At step <NUM>, the wound dressing <NUM> is provided. The wound dressing <NUM> can include the tubing connector <NUM>, the membrane <NUM>, and the pad <NUM> (such as a sponge or other filling material). The wound dressing <NUM> can be intended to be used, and can be suitable to be used, without an additional barrier (such as the barrier <NUM>). However, adding the wound dressing <NUM> can be beneficially added as described below in steps <NUM> and <NUM>.

At step <NUM>, the wound dressing <NUM> is prepared. Components of the wound dressing <NUM> can be removed from packaging, assembled, and/or trimmed. For example, the pad <NUM> can be trimmed to a size and shape suitable for being positioned in the wound <NUM> of the patient <NUM>. The wound dressing <NUM> can now ready to be applied to the wound <NUM>, except when it is deemed desirable to use the barrier <NUM>. If the wound dressing <NUM> is to be used without the dressing <NUM>, the method <NUM> can proceed to step <NUM>. If the benefits of the barrier <NUM> are desired, steps <NUM>, <NUM>, and <NUM> can be performed.

At step <NUM>, the barrier <NUM> is provided. The barrier <NUM> can be intended for use with the wound dressing <NUM> and similar wound dressings to improve treatment of the patient <NUM>, yet the barrier <NUM> is provided separately from the wound dressing <NUM>. At step <NUM>, the barrier <NUM> is prepared. The barrier <NUM> can be removed from packaging. In embodiments where the barrier <NUM> is a single, integrally formed barrier, no assembly is needed. The barrier can be trimmed to a size and shape suitable for being positioned in the wound <NUM> under the pad <NUM> to separate the pores of the pad <NUM> from some or all of the surface of the wound <NUM>.

At step <NUM>, the barrier <NUM> can be positioned in the wound. The barrier <NUM> can be positioned to substantially cover all (or substantially all) of the surface of wound tissue. Alternatively, the barrier <NUM> can be positioned to cover only a portion of the tissue in the wound, such as the muscle tissue <NUM>. Covering the muscle tissue <NUM> can be beneficial because the muscle tissue <NUM> can tend to grow into the pores of spongey material like the pad <NUM>, and consequently, pain and tissue damage can result when the pad <NUM> is removed from the wound <NUM> when such tissue ingrowth occurs. Other tissue, such as fatty tissue <NUM>, can be less prone to ingrowth, and consequently, it can be less important to cover such fatty tissue <NUM> in such circumstances. Nonetheless, the fatty tissue <NUM> and other tissue can also be covered by the barrier <NUM>.

At step <NUM>, the wound dressing <NUM> can be applied. The pad <NUM> can be placed in the wound <NUM> on top of the barrier <NUM> and the membrane <NUM> can be applied to cover the wound <NUM>. The tubing connector <NUM> can be applied so as to connect to tubing for applying NPWT.

At step <NUM>, negative pressure wound therapy (NPWT) can be applied to the wound <NUM>. The EVR <NUM> can work in conjunction with a vacuum source to apply negative pressure to the wound <NUM> in order to aid in healing.

When the wound dressing <NUM> is applied without the barrier <NUM>, the wound dressing <NUM> can be used for a period of <NUM>-<NUM> hours or less. Even when removed within <NUM>-<NUM> hours or less, tissue ingrowth can occur potentially causing pain, tissue damage, and breakage of portions of the spongy material of the pad <NUM> and remaining in the wound <NUM> when the pad <NUM> is pulled out of the wound <NUM>.

When the wound dressing <NUM> is applied with the barrier <NUM> positioned under the pad <NUM>, pain, tissue damage, and/or breakage can be reduced. In some applications, the wound dressing <NUM> and the barrier <NUM> can be left in for longer than <NUM>-<NUM> hours because the barrier <NUM> can inhibit tissue ingrowth. Accordingly, use of the barrier <NUM> can increase the effective life and duration of each wound dressing <NUM>.

<FIG> show perspective views of a wound dressing <NUM> for NPWT and a barrier <NUM> for use in the wound dressing <NUM>. The wound dressing <NUM> can be suitable for use with relatively long (or deep) and narrow wounds, such as gunshot wounds and/or cutaneous fistulas. The wound dressing <NUM> can include a membrane <NUM>, a pad <NUM>, and the barrier <NUM>. The barrier <NUM> can be wrapped substantially or entirely around a circumference of the pad <NUM>. An irrigation tube (or lumen) <NUM> can be used to supply irrigation to the wound dressing <NUM>. A suction tube (or lumen) <NUM> can be used to apply negative pressure to the wound dressing <NUM>.

In some embodiments, components and features of the wound dressing <NUM> can be similar to those described above (e.g. for wound dressing <NUM>) and also have some differences suitable for use in treating relatively long and narrow wounds. For example, the pad <NUM> can be a foam pad (e.g. a foam sponge) like that described above for the pad <NUM>, except the pad <NUM> is long and narrow.

Additionally, the barrier <NUM> can have features similar to barriers described above. For example, some embodiments of the barrier <NUM> can be a porous barrier (similar to the barrier <NUM>) that provides physical separation between the wound and an in-growth inducing surface of the pad <NUM>. In some embodiments, the barrier <NUM> can include irrigation channels similar to the barrier <NUM> or the barrier <NUM>.

As shown in <FIG>, the barrier <NUM> can be substantially nail-shaped, with a relatively broad and flat connection (or head) portion <NUM> and a relatively long and narrow cylinder (or shaft) portion <NUM>. The barrier <NUM> defines a relatively long and narrow hollow central core <NUM>. The cylinder portion <NUM> can be porous to allow fluid flow through the cylinder portion <NUM> into the central core <NUM> during NPWT. The cylinder portion <NUM> can prevent tissue ingrowth into the pad <NUM> in the central core <NUM>. The barrier <NUM> can be perforated silicone or other suitable material. The barrier <NUM> can have a geometric structure, such as a honeycomb shaped structure similar to what is shown in <FIG>.

<FIG> show a series of steps for trimming the dressing <NUM>. As shown in <FIG>, the dressing <NUM> can be trimmed by cutting through the barrier <NUM>, and possibly the pad <NUM> as well (e.g. trimming with a knife or scissors). The dressing <NUM> can be manufactured to a size that is longer than a depth of the wound to be treated, and then be cut to a length that is deemed appropriate for the depth of the wound. As shown in <FIG>, the pad <NUM> can be exposed at a tip of the dressing <NUM>, uncovered by the barrier <NUM> after being cut. Accordingly, risk of tissue ingrowth can be increased at the tip of the dressing <NUM> where the pad <NUM> is uncovered by the barrier <NUM> due to being cut. As shown in <FIG>, a portion of the pad <NUM> can be pulled out of the distal end of the barrier <NUM> and then cut shorter. As shown in <FIG>, the pad <NUM> can then be pulled back into the barrier <NUM> by a distance suitable to prevent or reduce the risk of tissue ingrowth into the pad <NUM>. Accordingly, the dressing <NUM> can include a gap <NUM> at the distal end of the dressing <NUM> where the barrier <NUM> extends further than the pad <NUM>.

<FIG> show steps for closing the dressing <NUM> after being cut, such as by suturing. As shown in <FIG>, a distal end of the barrier <NUM> can have an opening <NUM> after being cut. In some embodiments, the dressing <NUM> can be sized and shaped such that the barrier <NUM> can prevent or reduce the risk of tissue ingrowth into the pad <NUM> even without the opening <NUM> being closed. In other embodiments, the dressing <NUM> can benefit from being closed after being cut to size. Accordingly, the opening <NUM> can be closed, such as by suturing. For example, the opening <NUM> can be sutured closed via a vessel loop <NUM>. Alternatively the opening <NUM> can be closed by a silicone bond or other suitable mechanism.

<FIG> show schematic views of barriers for wound dressings having different shapes. <FIG> is a schematic view of the dressing <NUM> with the barrier <NUM> that is substantially shaped like a nail. The barrier <NUM> can have the flat connection (or head) portion <NUM> and the relatively long and narrow cylinder (or shaft) portion <NUM>.

<FIG> shows a schematic view of a dressing <NUM> with a barrier <NUM> that is substantially shaped like a funnel. The barrier <NUM> can have a connection portion <NUM> that is substantially frustoconical and a cylinder portion <NUM> (similar to the cylinder portion <NUM>) extending from a narrow end of the connection portion <NUM>. <FIG> shows a schematic view of a dressing <NUM> with a barrier <NUM> that is substantially shaped like a kettle. The barrier <NUM> can have a connection portion <NUM> that is relatively wide and flat much like the connection portion <NUM> of the barrier <NUM>. The barrier <NUM> can have a shaft portion <NUM> that is rounded or bulging as compared to the cylinder portion <NUM> and the cylinder portion <NUM>. Accordingly, <FIG> show some of the various shapes suitable for treating relatively deep wounds.

In some embodiments, the barriers <NUM>, <NUM>, and <NUM> can be used with a pad (e.g. the pad <NUM> which can be a foam sponge) positioned inside the barriers <NUM>, <NUM>, and <NUM>. In other embodiments, the barriers <NUM>, <NUM>, and <NUM> can be used without any pad or similar structure positioned inside the barriers <NUM>, <NUM>, and <NUM>.

<FIG> is a perspective view of a dressing <NUM> having a combined pad <NUM> (such as a sponge) and barrier <NUM>. The barrier <NUM> can be attached or attachable to the pad <NUM>. In some embodiments, the pad <NUM> can have a thickness of <NUM>-<NUM> and the barrier can have a thickness of <NUM>-<NUM>. The barrier <NUM> and the pad <NUM> can have some, all, or none of the features described above with respect to other examples of barriers and pads. For example, the barrier <NUM> can include perforations <NUM>. In some embodiments, the barrier <NUM> and the pad <NUM> can be combined and sold together, with the barrier <NUM> attached to the pad <NUM>. In such embodiments, the user need not assemble the barrier <NUM> and the pad <NUM>. The barrier <NUM> and the pad <NUM> can be sized to fit in a given wound or can be configured to be trimmed together to a size suitable for a given wound (e.g. a user can cut both the barrier <NUM> and the pad <NUM> to an appropriate size using scissors while the barrier <NUM> is attached to the pad <NUM>).

The dressing <NUM> can include a tubing system <NUM>, a membrane <NUM>, and an adhesive connection layer <NUM> (e.g. a "lily pad"). The membrane <NUM> can be positioned over the combined pad <NUM> and the barrier <NUM> to cover and seal the pad <NUM> and the barrier <NUM> in a wound. A hole <NUM> can be cut in the membrane <NUM> at a location aligned with the pad <NUM> and the adhesive connection layer <NUM> can be adhered to the membrane <NUM> at the hole <NUM> to connect the tubing system <NUM> to the hole <NUM> to provide suction to the dressing <NUM> and the corresponding wound.

<FIG> are views of features of the barrier <NUM>. <FIG> shows the barrier <NUM> having the base layer <NUM> with a plurality of perforations <NUM>. A plurality of walls <NUM> can be positioned above (and/or extend from) the base layer <NUM> to form a honeycomb or other geometric shape. While <FIG> shows the barrier <NUM> having only two honeycomb structures, the barrier <NUM> can include more honeycomb (or other shaped) structures repeating over some, most, or all of the base layer <NUM> (see, e.g. <FIG>). In some embodiments, the barrier <NUM> can have a combined thickness of the base layer <NUM> and the walls <NUM> of <NUM>-<NUM>. <FIG> shows a view of the base layer <NUM> and its perforations <NUM>. <FIG> shows a view of the walls <NUM> forming three honeycomb structures.

<FIG> is a perspective view of a dressing <NUM> having a combined pad <NUM> (such as a sponge) and barrier <NUM> with irrigation tubing <NUM>. The dressing <NUM> can be similar to the dressing <NUM> (shown in <FIG>) except the dressing <NUM> includes irrigation tubing <NUM>. An irrigation supply tube <NUM> can be connected to an adhesive connection layer <NUM> (e.g. a "lily pad") that has connections for both the irrigation supply tube <NUM> and the tubing system <NUM> (for providing suction). An extension irrigation tube <NUM> can extend through the pad <NUM>, connecting the irrigation supply tube <NUM> to the irrigation tubing <NUM> in the barrier <NUM>. The irrigation tubing <NUM> in the barrier <NUM> can extend radially outward to supply irrigant to a perimeter of the barrier <NUM>. Suction applied via the tubing system <NUM> can draw irrigant and exudate from the wound up through the perforations <NUM>, through the pad <NUM>, through the adhesive connection layer <NUM>, and out through the tubing system <NUM>.

<FIG> is a perspective view of a dressing <NUM> having a combined pad <NUM> (such as a sponge) and barrier <NUM> with a suction manifold <NUM> and irrigation tubing <NUM>. The dressing <NUM> can be similar to the dressing <NUM> (shown in <FIG>) except the dressing <NUM> includes the suction manifold <NUM>. An extension suction tube <NUM> can connect the suction manifold <NUM> to the tubing system <NUM>. The suction manifold <NUM> can be positioned on top of the pad <NUM> to distribute the suction force over an area on top of the pad <NUM>. Fluid can flow into the suction manifold <NUM> through a bottom surface of the suction manifold <NUM> that is either open or substantially open. Fluid can flow out of the suction manifold <NUM> through a hole in the top of the suction manifold <NUM> where the extension suction tube <NUM> is connected to the suction manifold <NUM>.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of the disclosed technology or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular disclosed technologies. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment in part or in whole. Moreover, although features may be described herein as acting in certain combinations and/or initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. Similarly, while operations may be described in a particular order, this should not be understood as requiring that such operations be performed in the particular order or in sequential order, or that all operations be performed, to achieve desirable results. Particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims.

Claim 1:
A barrier (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) for use in negative pressure wound therapy, the barrier comprising:
a base layer (<NUM>) defining a plurality of perforations (<NUM>) extending entirely through the base layer (<NUM>), wherein the plurality of perforations are positioned, sized, and configured to allow flow therethrough for negative pressure wound therapy, wherein the base layer defines a top surface (<NUM>) and a bottom surface (<NUM>) that is configured to be positioned adjacent the surface of a wound (<NUM>); and
top surface structures (<NUM>, <NUM>,<NUM>) positioned on the top surface (<NUM>) of the base layer, wherein the top surface structures are positioned, sized, and configured to space porous foam material (<NUM>) away from the perforations of the base layer when porous foam material is positioned on top of the barrier after the barrier is positioned in the wound (<NUM>).