Patent Application
20210145648
This application relates generally to medical treatment systems and, more particularly, but not by way of limitation, to apparatus, dressings, systems, and methods that may be suitable for treating a tissue site.
Clinical studies and practice have shown that providing a reduced pressure in proximity to a tissue site may augment and accelerate growth of new tissue at the tissue site. The applications of this phenomenon are numerous and may, without limitation, involve wound healing. This treatment may be referred to as “negative pressure wound therapy,” “reduced pressure therapy,” or “vacuum therapy.” Reduced pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, micro-deformation of tissue, and macro-deformation of tissue. These benefits may result in increased development of granulation tissue and faster healing times. Conventional reduced pressure therapy may employ a reduced pressure source and associated system and control components to communicate the reduced pressure to tissue at the tissue site through a manifold or porous device.
Some tissue sites or wounds may not be a candidate for conventional reduced pressure therapy, but may benefit from the increased development of granulation tissue and faster healing times offered by this treatment. Accordingly, improvements to apparatus, dressings, systems, and methods for stimulating tissue growth without the application of reduced pressure and the associated system and control components may be desirable.
In some illustrative, non-limiting examples, a system for stimulating tissue growth at a tissue site may include an interactive body that may be configured to create tissue deformation at the tissue site. The interactive body may include a tissue contact surface, a plurality of struts, a plurality of voids, a tissue interface pattern, and a body mass. The tissue contact surface may be configured to contact the tissue site. The plurality of struts and the plurality of voids may be exposed at the tissue contact surface. The tissue interface pattern may be defined by the plurality of struts and the plurality of voids at the tissue contact surface. The tissue interface pattern may be configured to engage the tissue site, and the body mass may be configured to create the tissue deformation in combination with the tissue interface pattern.
In some illustrative, non-limiting examples, a system for stimulating tissue growth at a tissue site may include a porous foam. The porous foam may include a tissue contact surface and a plurality of struts positioned or exposed at the tissue contact surface. The plurality of struts may be configured to contact the tissue site and to create tissue deformation at the tissue site. In some examples, the porous foam may have a porosity between about 20 pores per inch to about 35 pores per inch. Further, the porous foam may be configured to provide a contact force at least between the plurality of struts and the tissue site to create the tissue deformation without the application of a reduced pressure.
In some illustrative, non-limiting examples, the system may include a plurality of voids. The plurality of voids and the plurality of struts may be exposed at the tissue contact surface and configured to engage the tissue site. Further, in some non-limiting examples, the porous foam may include a hydrophobic reticulated polyurethane foam. In some non-limiting examples, an absorbent member may be positioned proximate to the porous foam such that the porous foam is configured to be positioned between the absorbent member and the tissue site. The absorbent member may be configured to absorb a fluid communicated from the tissue site through the porous foam, and to swell and to exert an auxiliary force on the tissue site through the porous foam when the fluid is absorbed. In some non-limiting examples, the system may include a sealing member configured to provide a sealed space between the sealing member and the tissue site. The porous foam and the absorbent member may be configured to be positioned in the sealed space.
In some illustrative, non-limiting examples a method for stimulating tissue growth at a tissue site may include providing an interactive body comprising a tissue contact surface. The tissue contact surface may include a plurality of struts and a plurality of voids exposed at the tissue contact surface. Further, the method may include positioning the tissue contact surface in contact with the tissue site, and engaging the plurality of struts and the plurality of voids with a tissue at the tissue site to create a contact force on the tissue. Further, the method may include deforming the tissue at the tissue site by operation of the contact force without an application of reduced pressure.
Other aspects, features, and advantages of the illustrative examples will become apparent with reference to the drawings and detailed description that follow.
In the following detailed description of illustrative example embodiments, reference is made to the accompanying drawings that form a part of this disclosure. Other embodiments may be used, and logical, structural, mechanical, electrical, and chemical changes may be made without departing from the scope of this disclosure. Further, the description may omit certain information known to those skilled in the art. The description is also non-limiting, and the appended claims define the scope of the illustrative embodiments.
Referring to
As used herein, the term “tissue site” may refer to a wound or defect located on or within any tissue, including but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. The term “tissue site” may further refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it is desired to add or promote the growth of additional tissue. Further, as used throughout this disclosure, “or” does not require mutual exclusivity.
The tissue site 112 may extend through or otherwise involve an epidermis 116, a dermis 118, and a subcutaneous tissue 120. The tissue site 112 may be a sub-surface tissue site as depicted in
In some embodiments, the system 110 may include a sealing member 128. The sealing member 128 may be configured to provide a sealed space 130 between the sealing member 128 and the tissue site 112. The interactive body 114 may be configured to be positioned in the sealed space 130.
The sealing member 128 may be formed from any material that allows for a fluid seal. A fluid seal may be a seal adequate to protect the tissue site 112 from contaminants. The sealing member may comprise, for example, one or more of the following materials: hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; hydrophilic silicone elastomers; an INSPIRE 2301 material from Expopack Advanced Coatings of Wrexham, United Kingdom having, for example, an MVTR (inverted cup technique) of 14400 g/m2/24 hours and a thickness of about 30 microns; a thin, uncoated polymer drape; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; polyurethane (PU); EVA film; co-polyester; silicones; a silicone drape; a 3M TEGADERM® drape; a polyurethane (PU) drape, such as one available from Avery Dennison Corporation of Pasadena, Calif.; polyether block polyamide copolymer (PEBAX), for example, from Arkema, France; Expopack 2327; or other appropriate material.
The sealing member 128 may be vapor permeable and liquid impermeable, thereby allowing vapor and inhibiting liquids from exiting the sealed space 130. In some embodiments, the sealing member 128 may be a flexible, breathable film, membrane, coating, or sheet having a high MVTR of, for example, at least about 300 g/m2 per 24 hours. In other embodiments, a low or no vapor transfer drape may be used. The sealing member 128 may comprise a range of medically suitable films having a thickness between about 15 microns (μm) to about 50 microns (μm). In some embodiments, the sealing member 128 may be a coating or layer adhered to or forming part of an exterior-facing surface of the interactive body 114 that is configured to face away or outward from the tissue site 112.
In some embodiments, the sealing member 128 may be deployed with an adhesive 132 or bonding agent to secure and seal the sealing member 128 to tissue at or around the tissue site 112, such as the epidermis 116. For example, the adhesive 132 or bonding agent may be positioned between the sealing member 128 and tissue or the epidermis 116 around the tissue site. The adhesive 132 or bonding agent may be any medically acceptable adhesive or agent, such as an acrylic adhesive. In some embodiments, the adhesive 132 or bonding agent may form at least part of a surface of the sealing member 128, such as a coating, configured to face the tissue site 112 or tissue around the tissue site 112. In some embodiments, the adhesive 132 or bonding agent may be a separate component or layer of material, such as, for example, a hydrogel that may be positioned between the sealing member 128 and the tissue site 112 or tissue around the tissue site 112.
In some embodiments, the system 110 may include an absorbent member 138. The absorbent member 138 may be positioned proximate to the interactive body 114 in the sealed space 130 such that the interactive body 114 is positioned between the absorbent member 138 and the tissue site 112. The absorbent member 138 may be configured to absorb fluid communicated from the tissue site 112, and to swell upon absorption of the fluid. The fluid may be communicated from the tissue site 112 through the interactive body 114 to the absorbent member 138, for example, by a wicking action, by an absorbent gradient, by exposure to fluid in or around the interactive body 114, or other phenomena. The absorbent member 138 may be configured to exert an auxiliary force 139 on the tissue site 112, for example and without limitation, by operation of the swelling and expansion of the absorbent member 138 upon absorption of fluid, the fluid mass created by the absorption, or gravitational forces. The auxiliary 139 force may be exerted on the tissue site 112 through the interactive body 114, and may be directed toward, into, or along a surface or bed 140 of the tissue site 112. The auxiliary force 139 may also be enhanced by the positioning of the absorbent member 138 such that the absorbent member 138 is captured or held at the tissue site 112 by the sealing member 128 and placed between the sealing member and the interactive body 114.
The absorbent member 138 may be a hydrophilic material adapted to absorb fluid. In some embodiments, materials suitable for the absorbent member 138 may include, without limitation, super absorbent polymers and similar absorbent materials; LUQUAFLEECE® material; TEXSUS FP2326; BASF 402C; Technical Absorbents 2317, available from Technical Absorbents, Ltd. of Lincolnshire, United Kingdom; sodium polyacrylate super absorbers; cellulosics (carboxy methyl cellulose and salts such as sodium CMC); or alginates.
The interactive body 114 may have a thickness 144 as shown in
The interactive body 114 may also act as a manifold. The term manifold may refer to a substance or structure configured for delivering fluids to or removing fluids from a tissue site through a plurality of voids, pores, pathways, or flow channels. The plurality of voids, pores, pathways, or flow channels may be interconnected to improve the distribution of fluid provided to and removed from an area around the manifold. Examples of manifolds may include, without limitation, devices that have structural elements arranged to form flow channels, cellular foam, such as closed-cell or open-cell foam, porous tissue collections, sintered polymers, and liquids, gels, and foams that include or cure to include flow channels.
The term porosity may refer to a measurement, ratio, fraction, or comparison of an amount of the struts 148 relative to the voids 150 in the interactive body 114. The plurality of struts 148 and the plurality of voids 150 may be defined by a porosity. Similarly, the tissue interface pattern 152 may be defined by a porosity of the interactive body 114 at the tissue contact surface 146. Porosity, also known as pore density, may be measured in Pores Per Inch (PPI), which designates the number of pores in one linear inch. Although porosity and pore density may be used to describe a porous material, such as foam, these principles may apply to other non-foam structures that include a void space.
In some embodiments, the interactive body 114 may include a porous foam or be formed of a foam. For example, in some embodiments, the foam may be a hydrophobic, reticulated, open-cell polyurethane or polyether foam that may be fluid permeable. Further, in some embodiments, ionic silver may be added to the foam by, for example, a micro bonding process. Other substances, such as anti-microbial agents, may be added to the foam as well.
In some embodiments, a non-reticulated foam or a foam comprised of biocompatible materials other than polyurethane may be used. In one embodiment, a bioabsorbable foam or other porous substrate may be employed. Examples of other materials that may be suitable porous foams or porous substrates include those formed from acrylics, acrylates, thermoplastic elastomers (for example, styrene ethylene butene styrene (SEBS) and other block copolymers), polyether block polyamide (PEBAX), silicone elastomers, poly caprolactam, poly lactic acid, and polyolefins, such as polythene and polypropylene. Still other biocompatible materials may be used if capable of being formed or otherwise made into a porous substrate as described herein.
The tissue contact surface 146 of the interactive body 114 may have a porosity that is less than about 39 pores per inch. For example, in some embodiments, the tissue contact surface 146 of the interactive body 114 may have a porosity between about 20 pores per inch to about 35 pores per inch. In embodiments of the interactive body 114 that use a foam, the foam may similarly have a porosity that is less than about 39 pores per inch or, for example, a porosity between about 20 pores per inch to about 35 pores per inch. In some embodiments, the foam may be positioned at the tissue contact surface 146 of the interactive body 114 or form the tissue contact surface 146 of the interactive body 114. The foam may carry the plurality of struts 148 and the plurality of voids 150.
The tissue contact surface 146 of the interactive body 114 may be configured to contact the tissue site 112. In some embodiments, the interactive body 114 may be sized to fit within the edge 122 or outer boundary of the tissue site 112 such that the interactive body 114 does not overlap or contact tissue around the tissue site, such as the epidermis 116. The plurality of struts 148 and the plurality of voids 150 may be exposed at the tissue contact surface 146. The plurality of struts 148 and the plurality of voids 150 may be configured to be positioned in direct physical contact with the tissue site 112. At least the plurality of struts 148 may be configured to engage the tissue site 112 and to create tissue deformation at the tissue site 112. As the tissue site 112 deforms, stretches, or moves in response to the plurality of struts 148, tissue at the tissue site 112 may deformed, stretched, or moved to fill at least a portion of a volume of the voids 150. Accordingly, the voids 150 may engage the tissue site 112, without limitation, by operation of tissue being deformed, stretched, or moved into the voids 150. The plurality of struts 148 and the plurality of voids 150 at the tissue contact surface 146 may collectively define the tissue interface pattern 152. The tissue interface pattern 152 may be configured to engage the tissue site 112 analogous to the plurality of struts 148 and the plurality of voids 150.
For example, the interactive body 114 may provide the contact force 115 at least between the plurality of struts 148 and the tissue site 112 to create the tissue deformation without the application of an external force, such as reduced pressure. The struts 148 and the voids 150 carried on the tissue contact surface 146 may be urged toward the bed 140 of the tissue site 112 under the contact force 115. The contact force 115 may be created in part by the body mass 154 of the interactive body 114, which may be enhanced by other components of the system 110, such as, for example, the previously described absorbent member 138. As the tissue contact surface 146 moves toward the bed 140, each of the struts 148 may create a stress substantially normal or orthogonal to the bed 140 of the tissue site 112, creating a distribution of deformation or strain across the bed 140 of the tissue site 112. As a result of this deformation or strain, tissue in the bed 140 may be deformed, stretched, or moved into the voids 150 as shown in
For clarity, the contact force 115 is directed toward or into the bed 140 of the tissue site 112, and distributed across the bed 140, as shown in
As described herein, the tissue interface pattern 152 may be defined by the plurality of struts 148 and the plurality of voids 150 at the tissue contact surface 146. The tissue interface pattern 152 may be selectable according to the body mass 154, and the body mass 154 may be selectable according to the tissue interface pattern 152. For example, the tissue interface pattern 152 may be selected such that the plurality of struts 148 exposed at the tissue contact surface 146 have a shape or a surface area sized to create tissue deformation under the contact force 115 provided by the interactive body 114. The surface area of the plurality of struts 148 exposed at the tissue contact surface 146 may decrease as the size of the plurality of voids 150 increases. By way of example, a low porosity material having a porosity of 10 pores per inch will have a larger average void size or pore size compared to a high porosity material having a porosity of 60 pores per inch. Herein, a low porosity material may be a material that has a lower amount of pores per inch than a high porosity material having a higher amount of pores per inch. In a low porosity material, the larger size of the voids 150 or pores may occupy more space than the plurality of struts 148 in the tissue interface pattern 152, thereby reducing the surface area of the plurality of struts 148 exposed at the tissue contact surface 146 for engaging the tissue site 112. The plurality of struts 148 having a reduced surface area may require less of the contact force 115 to produce a desired amount of tissue deformation since the contact force 115 of this example will be exerted by a smaller surface area of the tissue interface pattern 152.
For example,
In
In
The body mass 154 may be configured to create a desired amount of tissue deformation in combination with the tissue interface pattern 152. The body mass 154 may be selectable according to the tissue interface pattern 152. For example, the body mass 154 may be selected by material properties or sized sufficiently to create a desired amount of tissue deformation with the tissue interface pattern 152. Alternatively, the tissue interface pattern 152 may be selected appropriately according to the size or material properties of the body mass 154. In some embodiments, the body mass 154 may correspond to a weight that may provide the contact force 115 of the interactive body 114, which may be enhanced by other components of the system 110, such as the previously described absorbent member 138 or the sealing member 128. Herein, the body mass 154 and the weight of the body mass 154 may be defined or selected according to the thickness 144 of the interactive body 114. The thickness 144 of the interactive body 114 may also be the same as a thickness of the body mass 154. In some embodiments, the thickness 144 of the body mass 154 or the interactive body 114 may be between about 2 millimeters to about 8 millimeters. In some particular embodiments, the thickness 144 of the body mass 154 or the interactive body 114 may be about 5 millimeters.
Continuing with the discussion of
A system, dressing, or method employing the interactive body 114 according to this disclosure may stimulate tissue growth, providing a wound bed ready for grafting or epithelialization without the application of an external force, such as a compressive force, that may be associated with the application of conventional negative pressure wound therapy (NPWT). Conventional dressings that do not use negative pressure, referred to as non-NPWT dressings, typically use non-adherent interface layers, silicones, and similar elements to make them non-adherent to the tissue, less susceptible to tissue in-growth, and less likely to cause tissue disruption. Accordingly, non-NPWT dressings are typically designed to reduce or eliminate mechanical interaction with tissue, limiting their ability to stimulate tissue growth.
NPWT dressings may be designed to mechanically interact with tissue as a result of compressive and other forces applied to the tissue through the dressing by negative pressure generated by a negative pressure source. Being designed for use with negative pressure, these NPWT dressings do not typically produce sufficient mechanical interaction with tissue to stimulate or accelerate tissue growth without the application of negative pressure. As described herein, the interactive body 114 according to this disclosure may have a porosity at the tissue contact surface 146 less than about 39 pores per inch. In contrast, typical NPWT dressings have a porosity greater than about 40 pores per inch, which minimizes tissue in-growth into the NPWT dressings that can occur as a result of the application of negative pressure.
Referring to testing results shown in
In some illustrative, non-limiting examples a method for stimulating tissue growth at a tissue site may include providing the interactive body 114 including the tissue contact surface 146. The tissue contact surface 146 may include the plurality of struts 148 and the plurality of voids 150 exposed at the tissue contact surface 146. Further, the method may include positioning the tissue contact surface 146 in contact with the tissue site 112, and engaging the plurality of struts 148 and the plurality of voids 150 with a tissue at the tissue site 112 to create the contact force 115 on the tissue. Further, the method may include deforming the tissue at the tissue site 112 by operation of the contact force 115 without an application of reduced pressure.
In some embodiments, the method may include positioning the absorbent member 138 proximate to the interactive body 114 such that the interactive body 114 is positioned between the absorbent member 138 and the tissue site 112. Further, the method may include exerting the auxiliary force 139 on the tissue from the absorbent member 138 through the interactive body 114. Exerting the auxiliary force 139 on the tissue may include swelling the absorbent member 138 by absorbing fluid communicated from the tissue site 112 to the absorbent member 138 through the interactive body 114.
In some embodiments, the method may include covering the absorbent member 138 and the interactive body 114 at the tissue site 112 with a sealing member 128. The sealing member 128 may be configured to provide a seated space 130 between the sealing member 128 and the tissue site 112.
In some embodiments, the interactive body 114 may include the body mass 154, and the plurality of struts 148 and the plurality of voids 150 may define the tissue interface pattern 152 as described herein. In such embodiments, the method may include selecting the body mass 154 to produce the contact force 115 for deforming the tissue in combination with the tissue interface pattern 152. Selecting the body mass 154 may include sizing the body mass 154 to have a weight sufficient to produce the contact force 115 for deforming the tissue in combination with the tissue interface pattern 152.
In some embodiments, the method may include configuring the tissue interface pattern 152 to produce the contact force 115 for deforming the tissue in combination with the body mass 154. Configuring the tissue interface pattern 152 may include sizing the plurality of voids 150 and the plurality of struts 148 to produce the contact force 115 for deforming the tissue in combination with the body mass 154.
In some embodiments, the method may include determining a size of the body mass 154 to produce the contact force 115 as a function of a shape, geometry, or surface area of the tissue interface pattern 152. In some embodiments, the method may include determining a geometry or a surface area of the tissue interface pattern 152 to produce the contact force 115 as a function of a size of the body mass 154.
In some embodiments, the interactive body 114 may include or be formed of a porous foam carrying the plurality of struts 148 and the plurality of voids 150 at the tissue contacting surface 146 as described herein. In some embodiments, the method may include selecting the porous foam to have a porosity configured to create the contact force 115 for deforming the tissue. In some embodiments, the method may include selecting the porous foam to have a porosity according to a granulation tissue formation rate desired at the tissue site 112. A decrease in the porosity may produce a larger pore size, which may correspond to an increase in the granulation tissue formation rate as described herein.
The porosity of the porous foam may be less than about 39 pores per inch. For example, in some embodiments, the porosity of the porous foam may be between about 20 pores per inch to about 35 pores per inch.
While many of the apparatus, systems, and methods described herein have been illustrated for use with tissue sites or wounds that are at or near the epidermis of a patient, the apparatus, systems, and methods may similarly be used to treat subcutaneous tissue sites, tunnel wounds, or other undermined areas of tissue.
Although the subject matter of this disclosure has been provided by way of example in the context of certain illustrative, non-limiting embodiments, various changes, substitutions, permutations, and alterations can be made without departing from the scope of this disclosure as defined by the appended claims. Any feature described in connection to any one embodiment may also be applicable to any other embodiment. As such, the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. Further, the steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate.
The present application claims the benefit, under 35 USC § 119(e), of the filing of U.S. Provisional Patent Application Ser. No. 62/517,425, entitled “Granulating Chronic Wound Dressing,” filed Jun. 9, 2017. The provisional application is incorporated herein by reference for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US18/34464 | 5/24/2018 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62517425 | Jun 2017 | US |
