Patent Document

RELATED APPLICATIONS 
       [0001]    This application is a continuation application of U.S. patent application Ser. No. 12/639,253, entitled “Reduced-Pressure Wound Treatment Systems and Methods Employing A Microstrain-Inducing Manifold,” filed Dec. 16, 2009 which claims the benefit, under 35 U.S.C. §119(e), of the filing of U.S. Provisional Patent Application Ser. No. 61/140,662, entitled “Reduced-Pressure Wound Treatment Systems and Methods Employing A Microstrain-Inducing Manifold,” filed 24 Dec. 2008, which is incorporated herein by reference for all purposes. This application is co-pending with U.S. application Ser. No. 12/639,288, filed 16 Dec. 2009, entitled, “Reduced-Pressure Wound Treatment Systems and Methods Employing Manifold Structures” (VAC.0904US). 
     
    
     BACKGROUND 
       [0002]    The present invention relates generally to medical treatment systems and, more particularly, to reduced-pressure wound treatment systems and methods employing microstrain-inducing manifolds. 
         [0003]    Clinical studies and practice have shown that providing a reduced pressure in proximity to a tissue site augments and accelerates the growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but application of reduced pressure has been particularly successful in treating wounds. This treatment (frequently referred to in the medical community as “negative pressure wound therapy,” “NPWT,” “reduced pressure therapy,” or “vacuum therapy”) provides a number of benefits, which may include faster healing and increased formulation of granulation tissue. 
         [0004]    Negative pressure therapy, or reduced-pressure therapy, has been used to promote healing across a wide range of wound types. Typically, an open-cell foam is placed directly into the wound bed. A drape is then used to cover the dressing and seal the wound. The sealing member is then fluidly coupled to a reduced-pressure therapy unit to provide negative pressure, or reduced pressure, to the wound through the foam. While this approach has produced meaningful results, shortcomings and areas of desired of improvement remain. 
       BRIEF SUMMARY 
       [0005]    Shortcomings with wound care systems and methods are addressed by the illustrative embodiments herein. According to one illustrative embodiment, a reduced-pressure wound treatment system for treating tissue on a patient includes a microstrain-inducing manifold for disposing proximate the tissue that includes a plurality of shaped projections for creating microstrain within the tissue, a sealing member for placing over the tissue and microstrain-inducing manifold and operable to form a fluid seal over the tissue and microstrain-inducing manifold, and a reduced-pressure subsystem for delivering a reduced pressure to the sealing member. The shaped projections comprise tapered projections. 
         [0006]    According to another illustrative embodiment, a microstrain-inducing manifold for treating tissue on a patient includes a plurality of shaped projections for creating microstrain within the tissue. The shaped projections comprise tapered projections. 
         [0007]    According to another illustrative embodiment, a reduced-pressure wound treatment system for treating tissue on a patient includes a microstrain-inducing manifold for disposing proximate the tissue. The microstrain-inducing manifold includes a plurality of interconnected nodes. At least one of the interconnected nodes includes at least one shaped projection for creating microstrain within the tissue. The shaped projection may be an angled projection. The system further includes a sealing member for placing over the tissue and manifold. The sealing member is operable to form a fluid seal over the tissue and microstrain-inducing manifold. The system further includes a reduced-pressure subsystem for delivering a reduced pressure to the sealing member. 
         [0008]    According to another illustrative embodiment, a microstrain-inducing manifold for treating tissue on a patient includes a plurality of interconnected nodes. At least one of the interconnected nodes includes at least one shaped projection for creating microstrain within the tissue. The shaped projection may be an angled projection. 
         [0009]    According to another illustrative embodiment, a method for treating tissue on a patient includes placing a microstrain-inducing manifold proximate the tissue of the patient. The microstrain-inducing manifold includes a plurality of shaped projections for creating microstrain within the tissue. The shaped projections may be tapered projections. The method further includes disposing a sealing member over the microstrain-inducing manifold and the patient&#39;s epidermis; forming a fluid seal between the sealing member and the patient&#39;s epidermis; and providing reduced pressure to the microstrain-inducing manifold whereby the plurality of shaped projections create microstrain within the tissue. 
         [0010]    Other features and advantages of the illustrative embodiments will become apparent with reference to the drawings and detailed description that follow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    A more complete understanding of the present invention may be obtained by reference to the following Detailed Description when taken in conjunction with the accompanying Drawings wherein: 
           [0012]      FIG. 1  is a schematic, perspective view of an illustrative, non-limiting embodiment of a reduced-pressure wound treatment system for treating a wound on a patient shown over a wound; 
           [0013]      FIG. 2  is a schematic, cross-sectional view of a portion of the system of  FIG. 1  taken along line  2 - 2  in  FIG. 1 ; 
           [0014]      FIG. 3A  is a schematic, perspective view of an illustrative, non-limiting embodiment of a microstrain-inducing manifold for use in treating a tissue site, such as a wound, on a patient as part of an illustrative, non-limiting embodiment of a reduced-pressure wound treatment system; 
           [0015]      FIG. 3B  is an enlarged detail of the perspective view of  FIG. 3A ; 
           [0016]      FIG. 3C  is a side view of a portion of an interconnected node and shaped projection of the microstrain-inducing manifold shown in  FIGS. 3A and 3B ; 
           [0017]      FIG. 4A  is a schematic, perspective view of an illustrative, non-limiting embodiment of a microstrain-inducing manifold for use in treating a tissue site; 
           [0018]      FIG. 4B  is a schematic, top view of the microstrain-inducing manifold of  FIG. 4A ; 
           [0019]      FIG. 5A  is a schematic, perspective view of an illustrative, non-limiting embodiment of a microstrain-inducing manifold for use in treating a wound on a patient; 
           [0020]      FIG. 5B  is an enlarged partial view of the microstrain-inducing manifold of  FIG. 5A ; 
           [0021]      FIG. 6A  is a schematic, perspective view of an illustrative, non-limiting embodiment of a microstrain-inducing manifold for use in treating a wound on a patient as part of an illustrative, non-limiting embodiment of a reduced-pressure wound treatment system; 
           [0022]      FIG. 6B  is an enlarged partial view of the microstrain-inducing manifold of  FIG. 6A ; and 
           [0023]      FIG. 7  is a schematic, side view of an illustrative, non-limiting embodiment of a microstrain-inducing manifold. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the invention. To avoid detail not necessary to enable those skilled in the art to practice the invention, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims. 
         [0025]    Referring now primarily to  FIGS. 1-3B , an illustrative, non-limiting embodiment of a reduced-pressure wound treatment system  100  for treating a tissue site  103  on a patient is presented. The tissue site  103  may, be, for example, a wound  102 , or damaged area of tissue, on a patient. The tissue site  103  may be the bodily tissue of any human, animal, or other organism, including bone tissue, adipose tissue, muscle tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, ligaments, or any other tissue. Unless otherwise indicated, as used herein, “or” does not require mutual exclusivity. While the reduced-pressure wound treatment system  100  is shown in the context of the wound  102 , it will be appreciated that the reduced-pressure wound treatment system  100  may be used to treat many different types of tissue sites  103  and wounds including area wounds, incisions, internal wounds, or other tissue sites. The reduced-pressure wound treatment system  100  is shown on the wound  102 , which is through the epidermis  104 , or generally skin, and the dermis  106  and reaching into a hypodermis, or subcutaneous tissue  108 . 
         [0026]    The reduced-pressure wound treatment system  100  generally includes a sealing member  110 , a microstrain-inducing manifold  112 , and a reduced-pressure subsystem  114 . As will be described further below, in operation the microstrain-inducing manifold  112  induces microstrain and may be referred to as a microstrain-inducing manifold. The microstrain-inducing manifold  112  has a first side  113  and a second, patient-facing side  115 . 
         [0027]    Among the numerous benefits of the reduced-pressure wound treatment system  100  is the biological response initiated by microstrain within the wound  102 . Microstrain results from pressure distributed with the microstrain-inducing manifold  112  to a tissue site  103 , such as a wound surface  105  of the wound  102 . It is believed that this action creates areas of cell surface strain, or microdeformation. The cells appear to respond to the strain by expressing special receptors on the surface of the cells and turning on genetic pathways in the cells, which promote healing activities. The healing activities may include increased metabolic activity, stimulation of fibroblast migration, increased cellular proliferation, extra cellular matrix production, and the formation of granulation tissue, as well as a decrease in edema and a subsequent improvement of perfusion at the tissue site  103 . With respect to the wound  102 , over time, granulation tissue fills the wound  102  and thereby further reduces volume and prepares the wound  102  for final closure by secondary or delayed primary intention. 
         [0028]    The sealing member  110  is generally formed from a flexible sheet. The sealing member  110  includes a first surface  120  and a patient-facing surface  122 . The sealing member  110  may be sized so that the sealing member  110  overlaps the wound  102  in such a manner that a drape extension  116  extends beyond the peripheral edge of the wound  102 . 
         [0029]    The sealing member  110  may be formed from any material that provides a fluid seal. As used herein, “fluid seal,” or “seal,” means a seal adequate to maintain reduced pressure at a desired site, e.g., a tissue site, given the particular reduced-pressure source involved. The sealing member may, for example, be an impermeable or semi-permeable, elastomeric material. “Elastomeric” means having the properties of an elastomer. Elastomeric generally refers to a polymeric material that has rubber-like properties. More specifically, most elastomers have ultimate elongations greater than 100% and a significant amount of resilience. The resilience of a material refers to the material&#39;s ability to recover from an elastic deformation. Examples of elastomers may include, but are not limited to, 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, EVA film, co-polyester, and silicones. Specific examples of sealing member materials include a silicone drape, 3M Tegaderm® drape, acrylic drape such as one available from Avery Dennison, or an incise drape. 
         [0030]    An attachment member  118  or device may be coupled to the sealing member  110 . The attachment member  118  is operable to removably couple the sealing member  110  to a patient&#39;s epidermis  104 . As used herein, the term “coupled” includes coupling via a separate object and includes direct coupling. The term “coupled” also encompasses two or more components that are continuous with one another by virtue of each of the components being formed from the same piece of material. Also, the term “coupled” may include chemical, such as via a chemical bond, mechanical, thermal, or electrical coupling. Fluid coupling means that fluid is in communication between the designated parts or locations. The sealing member  110  and attachment member  118  work together to form a fluid seal over the patient&#39;s epidermis  104 . The attachment member  118  may be any material suitable to help couple the sealing member  110  to a patient&#39;s epidermis  104 . For example, the attachment member  118  may be a pressure-sensitive adhesive, heat-activated adhesive, sealing tape, double-sided sealing tape, paste, hydrocolloid, hydrogel, hooks, sutures, etc. 
         [0031]    In the illustrative embodiment, the attachment member  118  is an adhesive layer  119  coupled to the patient-facing surface  122  of the drape extension  116 . The attachment member  118  may span the entire width or a portion of the patient-facing surface  122  of the sealing member  110 . Alternatively, in the case of sealing tape, the attachment member  118  may be applied over the entire first surface  120  of the sealing member  110 , or over the first surface of the drape extensions  116 . 
         [0032]    The microstrain-inducing manifold  112  is typically positioned between the second, patient-facing surface  122  of the sealing member  110  and the tissue site  103 , e.g., the wound  102 . The microstrain-inducing manifold  112  may be sized to approximate the estimated area of the wound  102 , although a larger or smaller size may be used in different applications. In the illustrative embodiment, the microstrain-inducing manifold  112  includes a plurality of interconnected nodes  124 . The interconnected nodes  124  may have a substantially circular cross-section, but it will be appreciated that the interconnected nodes  124  may have any suitable cross-section including, but not limited to, triangular, square, rectangular, hexagonal, octagonal, elliptical, etc. 
         [0033]    Each interconnected node  124  may include one or more shaped projections  126 . The shaped projections  126  are operable to create microstrain at the cellular level within the tissue site  103 , e.g., the wound  102 . While the illustrative embodiment shows each interconnected node  124  having a plurality of shaped projections  126 , it will be appreciated that some interconnected nodes  124  may be formed to avoid creating microstrains in certain areas. For example, one or more shaped projections  126  may be formed with a lower profile in a certain area or be absent all together in certain areas. Moreover, an additional manifold with no shaped projections, e.g., a smooth, laminar manifold, may be placed between at least a portion of the shaped projections  126  of the microstrain-inducing manifold  112  and a portion of the tissue site  103  to prevent the creation of strain in a certain area. It is believed that avoiding microstrains in certain areas is helpful to overall patient care. For example, it may be desirable to have a microstrain-inducing manifold  112  without projections  126  or that does not create microstrains in certain areas if a portion of the microstrain-inducing manifold  112  will lay on top of a vein, an artery, graft(s), objects used for adjunctive treatment or therapy (e.g., stents), exposed organs (e.g., heart or bowel), etc. 
         [0034]    The shaped projections  126  may be substantially the same size. Alternatively, some projections  126  may be larger or smaller than others. In one alternative, some shaped projections  126  may have a larger pitch than others, where “pitch” is defined by the angle  128  between a reference line  127  formed to have a right angle with a longitudinal axis  129  of the shaped projection  126  as shown in cross section in  FIG. 3C . Each shaped projection  126  has an outer surface  130  and a base  132 . While the shaped projections  126  in the illustrative embodiment are conical in shape, it will be appreciated that the shaped projections  126  may have any suitable shape capable of creating a microstrain within the wound  102 ; for example, the shaped projections  126  may be substantially cube shaped, pyramid shaped, hemispherically shaped, cylindrically shaped, triangularly shaped, cylindrically shaped with a distal recess, tapered, more elaborately shaped, etc. The shaped projections  126  are typically angled or tapered from a thick proximal end to a thin distal end or vice versa. In one embodiment, the shaped projections  126  are formed of the same material as the interconnected nodes  124 . Alternatively, at least some of the shaped projections  126  may be formed from a different material or the same material type of material with different properties than the interconnected nodes  124  or the other shaped projections  126 . Via material selection, one may control the stiffness of the interconnected nodes  124  such that greater microstrain may be provided in certain areas of the wound  102  versus others. The interconnected nodes  124 , shaped projections  126 , and the microstrain-inducing manifold  112  generally may be formed of a foam material or a non-foam material. 
         [0035]    The interconnected nodes  124  may be interconnected using a network of connecting members  134 . For example, the network of connecting members  134  may include a plurality of members  136  with each member  136  coupling adjacent interconnected nodes  124  to one another. In the illustrative embodiment, the members  136  have a substantially circular cross-section; however, it will be appreciated that the members  136  may have any suitable cross-section, including, but not limited to, triangular, square, rectangular, hexagonal, octagonal, elliptical, etc. In addition, as will be discussed below, the connecting members  134  may be configured such that the microstrain-inducing manifold  112  behaves anisotropically when subjected to a reduced pressure. 
         [0036]    The interconnected nodes  124 , connecting members  134 , and shaped projections  126  are arranged such that the microstrain-inducing manifold  112  includes a plurality of flow channels  140  ( FIG. 3B ) or pathways between the interconnected nodes  124 . The flow channels  140  improve distribution of fluids provided to and removed from the area of tissue around the microstrain-inducing manifold  112 . Thus, the microstrain-inducing manifold  112  is operable to assist in applying reduced pressure to, delivering fluids to, or removing fluids from a tissue site  103 . Moreover, the design of microstrain-inducing manifold  112  helps to avoid painful removal caused by in-growth, i.e., when growth of granulation tissue occurs into a manifold, and allows for easier removal from the tissue site  103 . 
         [0037]    The microstrain-inducing manifold  112  may be formed from any suitable material. By way of example only, and without limitation, the microstrain-inducing manifold  112  may be formed from an elastomer, a bioabsorbable/biodegradable polymer, etc. In addition, the manifold material may itself be, or may be combined with, a radio opaque material or a UV florescent material such that the wound  102  may be scanned with an X-ray or UV light in order to determine whether or not any remnants of the microstrain-inducing manifold  112  remain in the wound  102  after efforts have been made to remove the microstrain-inducing manifold  112  from the wound  102 . Additionally, the shaped projections  126 , or microstrain-inducing manifold  112  as a whole, may be coated with a drug (e.g., an anticoagulant), an antimicrobial agent (e.g., silver or copper), a hydrophilic material, etc. Optionally, the microstrain-inducing manifold  112  may also be formed with additional components, e.g., a delivery tube (not shown), whereby drugs or antimicrobial agents may be delivered to the wound  102  through the microstrain-inducing manifold  112 . 
         [0038]    The microstrain-inducing manifold  112  may be formed by any suitable process, including, but not limited to, micromolding, injection molding, casting, etc. The shaped projections  126  may be formed to be substantially integral with corresponding interconnected nodes  124  or may be coupled to corresponding interconnected nodes  124  by any suitable technique, including, but not limited to, mechanical fasteners, welding (e.g., ultrasonic or RF welding), bonding, adhesives, cements, etc. 
         [0039]    The microstrain-inducing manifold  112  may include numerous devices for creating point pressure or otherwise inducing microstrain. In one illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  includes limited contact points with the tissue site  103 . The contact points contribute to the inducement of microstrain at the tissue site  103 . Thus, in one illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  adjacent the tissue site  103  may have a projection surface area of X cm 2  associated with the second, patient-facing side, and yet the portion of the microstrain-inducing manifold  112  directly impinging on the tissue site  103  may be less than 40 percent of the surface area X (40% X). As used herein, “projection surface area” means the area that a general projection of an item would make on a flat surface. 
         [0040]    In another illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  adjacent the tissue site  103  may have a projection surface area of X cm 2  associated with the second, patient-facing side, and yet the portion of the microstrain-inducing manifold  112  directly impinging on the tissue site  103  may be less than 30 percent of the surface area X (30% X). In another illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  adjacent the tissue site  103  may have a projection surface area of X cm 2  associated with the second, patient-facing side, and yet the portion of the microstrain-inducing manifold  112  directly impinging on the tissue site  103  may be less than 20 percent of the surface area X (20% X). In one illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  adjacent the tissue site  103  may have a projection surface area of X cm 2  associated with the second, patient-facing side, and yet the portion of the microstrain-inducing manifold  112  directly impinging on the tissue site  103  may be less than 10 percent of the surface area X (10% X). In one illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  adjacent the tissue site  103  may have a projection surface area of X cm 2  associated with the second, patient-facing side, and yet the portion of the microstrain-inducing manifold  112  directly impinging on the tissue site  103  may be less than 5 percent of the surface area X (5% X). 
         [0041]    In still another illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  adjacent the tissue site  103  may have a projection surface area of X cm 2  associated with the second, patient-facing side, and yet the portion of the microstrain-inducing manifold  112  directly impinging on the tissue site  103  may be less than 2 percent of the surface area X (2% X). In one illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  adjacent the tissue site  103  may have a projection surface area of X cm 2  associated with the second, patient-facing side, and yet the portion of the microstrain-inducing manifold  112  directly impinging on the tissue site  103  may be less than 1 percent of the surface area X (1% X). In one illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  adjacent the tissue site  103  may have a projection surface area of X cm 2  associated with the second, patient-facing side, and yet the portion of the microstrain-inducing manifold  112  directly impinging on the tissue site  103  may be less than 0.5 percent of the surface area X (0.5% X). 
         [0042]    In one illustrative, non-limiting embodiment, the microstrain-inducing manifold  112  adjacent the tissue site  103  may have a projection surface area of X cm 2  associated with the second, patient-facing side, and yet the portion of the microstrain-inducing manifold  112  directly impinging on the tissue site  103  may be less than 0.2 percent of the surface area X (0.2% X). Referring to  FIG. 2 , the microstrain-inducing manifold  112  adjacent to tissue site  103   103 , e.g., wound surface  105 , may cover the wound surface  105 , and may have a projection surface area X, and yet the portion of microstrain-inducing manifold  112  directly impinging on the wound surface  105  may only be 0.2 percent of X. Referring to  FIG. 3C , it should be understood that the impinging portion may only be a portion of an outer surface  130  of each of the plurality of shaped projections  126 . 
         [0043]    The microstrain-inducing manifold  112  may be disposed proximate the wound  102  such that the interconnected nodes  124  engage the wound surface  105 . In one illustrative embodiment, the microstrain-inducing manifolds  112  are stacked on top of one another to substantially fill the wound  102 . However, it will be appreciated that a single microstrain-inducing manifold  112  may be employed or a multi-layer microstrain-inducing manifold may also be formed and used. The microstrain-inducing manifold  112  may be formed from a single interconnected node  124  with a shaped projection  126 ; multiple independent interconnected nodes  124  with shaped projections  126 ; or a group of interconnected nodes  124 , which include shaped projections  126 , that are interconnected with the connecting members  134 . 
         [0044]    It will also be appreciated that a single microstrain-inducing manifold  112  may be rolled up or folded over itself in order to fill the wound  102 . Furthermore, it will be appreciated that a single microstrain-inducing manifold  112  may be loaded into the wound  102  and an additional manifold placed atop the manifold  112 . Examples of additional manifolds that may be placed atop the microstrain-inducing manifold  112  include, without limitation, devices that have structural elements arranged to form flow channels, cellular foam such as open-cell foam, porous tissue collections, and liquids, gels and foams that include or cure to include flow channels. 
         [0045]    Referring again to  FIG. 1 , the reduced-pressure subsystem  114  includes a reduced-pressure source  142 , which may take many different forms. The reduced-pressure source  142  provides reduced pressure as a part of the reduced-pressure wound treatment system  100 . As used herein, “reduced pressure” generally refers to a pressure less than the ambient pressure at a tissue site that is being subjected to treatment. In most cases, this reduced pressure will be less than the atmospheric pressure at which the patient is located. Alternatively, the reduced pressure may be less than a hydrostatic pressure at the tissue site. Reduced pressure may initially generate fluid flow in the microstrain-inducing manifold  112 , a conduit  150 , and proximate the tissue site  103 . As the hydrostatic pressure around the tissue site  103  approaches the desired reduced pressure, the flow may subside, and the reduced pressure may be maintained. Unless otherwise indicated, values of pressure stated herein are gauge pressures. The reduced pressure delivered may be static or dynamic (patterned or random) and may be delivered continuously or intermittently. Although the terms “vacuum” and “negative pressure” may be used to describe the pressure applied to the tissue site, the actual pressure applied to the tissue site may be more than the pressure normally associated with a complete vacuum. Consistent with the use herein, an increase in reduced pressure or vacuum pressure typically refers to a relative reduction in absolute pressure. 
         [0046]    The reduced-pressure subsystem  114  provides reduced pressure. The reduced-pressure subsystem  114  includes a reduced-pressure source  142  that may be any source of a reduced pressure, such a vacuum pump, wall suction, etc. While the amount and nature of reduced pressure applied to a tissue site will typically vary according to the application, the reduced pressure will typically be between −5 mm Hg and −500 mm Hg. Pressure may be applied to the microstrain-inducing manifold  112  in other ways as well; for example, a pressure wrap may be used. 
         [0047]    In the illustrative embodiment of  FIG. 1 , the reduced-pressure source  142  is shown having a battery compartment  144  and a canister region  146  with windows  148  providing a visual indication of the level of fluid within canister  146 . An interposed membrane filter, such as hydrophobic or oleophobic filter, may be interspersed between the conduit  150 , or tubing, and the reduced-pressure source  142 . 
         [0048]    The reduced pressure supplied by the reduced-pressure source  142  is delivered through the conduit  150  to a reduced-pressure interface  152 , which may be an elbow port  154 . In one illustrative embodiment, the port  154  is a TRAC® technology port available from Kinetic Concepts, Inc. of San Antonio, Tex. The reduced-pressure interface  152  allows the reduced pressure to be delivered to the sealing member  110  and realized within an interior portion of sealing member  110  as well as the microstrain-inducing manifold  112 . In this illustrative embodiment, the port  154  extends through the sealing member  110  to the microstrain-inducing manifold  112 . 
         [0049]    In use, the reduced-pressure wound treatment system  100  may be applied to a patient&#39;s epidermis  104  over the tissue site  103 , e.g., wound  102 . The microstrain-inducing manifold  112  may be disposed proximate the tissue site  103 , e.g., disposed within the wound  102 , or may overlay a portion of the wound  102 . The sealing member  110  may be placed over the top of the microstrain-inducing manifold  112  such that drape extensions  116  extend beyond the periphery of the wound  102 . The drape extensions  116  are secured to the patient&#39;s epidermis  104  (or a gasket member, such an additional piece of over drape surrounding the wound edges) by the attachment member  118  in order to form a fluid seal over the wound  102 . As used herein, reference to forming a fluid seal with the patient&#39;s epidermis shall be deemed to also include forming a seal with a gasket proximate the wound  102 . 
         [0050]    The reduced-pressure interface  152  is applied, if not already installed, and the conduit  150  fluidly coupled at one end to the reduced-pressure interface  152 . The other end of the conduit  150  is fluidly coupled to the reduced-pressure source  142 . The reduced-pressure source  142  may be activated such that reduced pressure is delivered to the sealing member  110  and microstrain-inducing manifold  112 . The reduced pressure provides reduced-pressure treatment to the tissue site  103 , removes fluids, and may force the shaped projections  126  of the microstrain-inducing manifold  112  against the wound  102  such that they create a microstrain at the cellular level within the wound  102 . As previously suggested, the microstrain may promote cellular proliferation, formation of granular tissue, and other beneficial effects. Alternatively, the microstrain-inducing manifold  112  may be placed proximate the tissue site  103  and then pressure may be applied by using a wrap over the microstrain-inducing manifold  112  or other source of pressure. 
         [0051]    Referring now primarily to  FIGS. 4A and 4B , an illustrative, non-limiting embodiment of a microstrain-inducing manifold  212  for use as part of a reduced-pressure wound treatment, such as the reduced-pressure wound treatment system  100  in  FIG. 1 , is shown. The microstrain-inducing manifold  212  includes interconnected nodes  224 , which include shaped projections  226  extending from the interconnected nodes  224 . In the illustrative embodiment, the shaped projections  226  are conical in shape; however, it will be appreciated that the shaped projections  226  may be any suitable shape capable of creating microstrain within a wound as previously discussed. Moreover, while each interconnected node  224  of the illustrative embodiment includes two projections  226  (one directed up and one directed down for the orientation shown in  FIG. 4A ), it will be appreciated that any number of projections  224  may extend from each interconnected node  224  or that some of the interconnected nodes  224  may have no projections  224 . Also, in the illustrative embodiment, each projection  226  extends substantially normal from a corresponding interconnected node  224 , but it will be appreciated that each projection  226  may extend from the corresponding interconnected node  224  at any angle. 
         [0052]    The interconnected nodes  224  are spaced apart and interconnected by a network of connecting members  234  as clearly shown in  FIG. 4B . The network of connecting members  234  includes a plurality of curved members  236 . A plurality of flow channels  240  are formed between the interconnected nodes  224  and members  236 . The members  236  have curved surfaces  290  that are curved in a cooperative manner with one another or with the radius of one or more corresponding interconnected nodes  224  such that when the microstrain-inducing manifold  212  is subjected to a reduced pressure, the microstrain-inducing manifold  212  collapses (partially or fully) in two directions (e.g., along the x-axis  286  and y-axis  288 ) but not at all or to a lesser extent in a third direction (e.g., the z-axis  284 ). As the microstrain-inducing manifold  212  collapses, each curved surface  290  of each member  236  abuts or approaches a curved surface  290  of an adjacent member  236  or at least one corresponding interconnected node  224 . This may be particularly advantageous if the reduced-pressure wound treatment system is configured to assist in drawing the wound together during reduced pressure therapy. 
         [0053]    Referring now primarily to  FIGS. 5A and 5B , an illustrative, non-limiting embodiment of a manifold structure  412 , which is a form of a microstrain-inducing manifold, is presented. The manifold structure  412  is for use with a reduced-pressure wound treatment system, such as the reduced-pressure wound treatment system  100  of  FIG. 1 , is shown. The manifold structure  412  includes one or more longitudinal members  456 . The longitudinal members  456  may be coupled in a spaced relationship by lateral connecting members  460 . The lateral connecting members  460  may be coupled to the longitudinal members  456 . The longitudinal members  456  and lateral connecting members  460  are shown with circular cross-sections, but it should be appreciated that the longitudinal members  456  and lateral connecting members  460  may have any suitable cross-sectional shape. While reference is made to longitudinal and lateral members, the members  456 ,  460  need not be orthogonal but may have other relative angles. 
         [0054]    Each longitudinal member  456  of the manifold structure  412  includes one or more shaped projections  426  for creating a microstrain within a wound. The longitudinal members  456  and shaped projections  426  are arranged such that the manifold structure  412  includes a plurality of flow channels  440  or pathways between adjacent longitudinal members  456  or between projections  426 . The flow channels  440  facilitate distribution of fluids provided to and removed from the area of tissue around the manifold structure  412 . It should be understood that any combination of longitudinal members  456  and lateral members  460  may be used. For example, the manifold structure  412  may be formed by a longitudinally connected group of longitudinal members  456  with projections  426 . There are eight such longitudinal groups shown in  FIG. 5A , and while shown with the lateral connecting members  460 , the lateral connecting members  460  may be omitted in some embodiments. Moreover, while only lateral connecting members  460  are shown on the ends, it should be understood that any number of permutations are possible, and lateral members  460  may be distributed at various locations between the longitudinal members  456 . 
         [0055]    In the illustrative embodiment, each shaped projection  426  projects substantially normal from the corresponding longitudinal member  456 . As used here, “normal” is a vector which perpendicular to that surface. For a non-flat surface, the normal vector may be taken at a point and is the same as a normal to the tangent plane at that point. It should be appreciated, however, that each shaped projection  426  may project at any angle relative to the corresponding longitudinal member  456 . Each shaped projection  426  may include a columnar body  427 , which has a first outer diameter (D 1 ), and an enlarged member  429 , which has a second outer diameter (D 2 ). Each enlarged member  429  is positioned at the distal end of an associated columnar body  427 . Each columnar body  429  may have any shape, e.g., the cross-section may be a circular, square, elliptical, irregular, etc., and may vary along its longitudinal dimension. The enlarged member  429  may be a spherical member as shown or may take any other shape, such as rounded cylindrical member, a cubical member, or an irregular shape. The second outer diameter (D 2 ) of the enlarged member  429  is greater than the first outer diameter (D 1 ) of the columnar body  427 , i.e., D 2 &gt;D 1 . In this regard, the shaped projections  426  may be considered to be tapered from a larger distal end to a smaller proximal end. 
         [0056]    Each shaped projection  426  may have any suitable shape capable of creating a microstrain within the wound when the shaped projection  426  impinges upon the wound. Additionally, in the illustrative embodiment, the shaped projections  426  have substantially equal heights, but it will be appreciated that the shaped projections  426  may have varying heights along each longitudinal member  456  or among the plurality of longitudinal members  456 . Also, it will be appreciated that certain portions of certain longitudinal members  456  may not have shaped projections  426  such that microstrain is not provided to certain areas within the wound. As with the microstrain-inducing manifolds previously discussed, the manifold structure  412  may be formed using any suitable process, including, but not limited to, micromolding, injection molding, casting, etc. The shaped projections  426  may be formed to be substantially integral with corresponding longitudinal members  456  or may be coupled to corresponding longitudinal members  456  by any suitable technique including, but not limited to, mechanical fasteners, welding (e.g., ultrasonic or RF welding), bonding, adhesives, cements, etc. 
         [0057]    In use, the manifold structure  412  is placed proximate the tissue site, e.g., wound, and a sealing member is deployed over the manifold structure  412  and tissue site. Reduced pressure may then be applied or alternatively a direct pressure may be applied. In some embodiments, e.g., embodiment with widely spaced lateral members  460 , when the manifold structure  412  is subjected to a reduced pressure, the manifold structure  412  may behave anisotropically. In other words, when the manifold structure  412  is subjected to a reduced pressure, in addition to the shaped projections  426  being forced into the wound to create microstrain, the longitudinal members  456  may move laterally towards each other. Each longitudinal member  456  move closer to an adjacent longitudinal member  456  than the adjacent longitudinal members  456  were prior to the introduction of the reduced pressure. At the same time, the manifold structure  412  does not substantially contract in a direction substantially parallel to the longitudinal members  456 . 
         [0058]    If the lateral connecting members  460  are omitted, even further contraction may be possible. The manifold structure  412  may deform more in a direction substantially perpendicular to the longitudinal members  456  (as illustrated by arrows  458  in  FIG. 5A ) without a proportional deformation in the direction parallel with the longitudinal members  456 . The deformation is typically within the same plane. This may be advantageous if the system employs other components, such as an anisotropic drape or another manifold, for drawing the wound together during reduced pressure therapy wherein the illustrative manifold structure  412  contracts in a manner complimentary therewith. If spaced lateral connecting members  460  are used in sufficient number, very little contraction may take place. In an alternative embodiment, the manifold structure  412  is configured such that some longitudinal members  456  are arranged substantially perpendicular to other longitudinal members  456  whereby the manifold structure  412  partially contracts, or contracts in a more limited manner, in two directions within the same plane when subjected to a reduced pressure. 
         [0059]    Referring now primarily to  FIGS. 6A and 6B , another illustrative, non-limiting embodiment of a microstrain-inducing manifold  512  for use with a reduced-pressure wound treatment system, such as a reduced-pressure wound treatment system  100  ( FIG. 1 ), is shown. The microstrain-inducing manifold  512  includes a mat  558 , or base, from which a plurality of shaped projections  526  extend. The mat  558  has a first side  513  and a second, patient-facing side  515 . In the illustrative embodiment, the shaped projections  526  are tapered and in particular are substantially conical in shape, but it will be appreciated that the projections  526  may have any suitable shape capable of creating microstrain within the wound. Also, while the illustrative embodiment shows the projections  526  extending substantially normal, i.e., perpendicular, from the mat  558 , it will be appreciated that the projections  526  may extend from the mat  558  at any suitable angle. Furthermore, in the illustrative embodiment, the projections  526  have substantially equal heights, but the mat  558  may include projections  526  of varying heights. Portions of the mat  558  may not have any projections such that microstrain is not provided to certain areas within the wound. Additionally, the stiffness of the shaped projections  526  and pitch of the shaped projections  526  may vary along the mat  558  such that the microstrain created by the projections  526  may be greater in certain areas of the wound versus other areas. 
         [0060]    The shaped projections  526  may be formed as integral portions of the mat  558  or coupled to the mat  558  by any suitable techniques, including but not limited to mechanical fasteners, welding (e.g., ultrasonic or RF welding), bonding, adhesives, cements, etc. The mat  558  may also includes a plurality of apertures  560  ( FIG. 6B ) disposed between the projections  526  to improve the distribution of fluids provided to and removed from the area of tissue around the microstrain-inducing manifold  512 . In an alternative embodiment, the shaped projections  526  may be formed from a modified honey on the mat  558 . The honey may be modified so that it is solid or partially solid and retains its shape for at least a certain amount of time whilst engaging the wound. Advantageously, the honey may act as an antimicrobial agent and may be absorbed by the patient after a period of time. Other dissolvable substances may be used as well. 
         [0061]    In operation, the microstrain-inducing manifold  512  is typically placed proximate the tissue site with the second, patient-facing side  515  facing the patient and covered with a sealing member. Reduced pressure is then delivered to the microstrain-inducing manifold  512 . When subjected to a reduced pressure, the microstrain-inducing manifold  512  impinges on the wound whereby the shaped projections  526  create microstrain within the wound. Additionally, exudate and other fluids pass through the mat  558  via the apertures  560 . Also, in some instances, it may be desirable to avoid increasing microstrain within the wound via the shaped projections  526 . In such an instance, the microstrain-inducing manifold  512  may be inverted such that the first side  513  of the mat  558  is placed against the wound and the shaped projections  526  extend towards the sealing member (not shown). Thus, the microstrain-inducing manifold  512  may assist in perfusion and fluid removal (via the apertures  560 ) without also increasing microstrain within the wound via the shaped projections  526 . 
         [0062]    Referring now primarily to  FIG. 7 , an illustrative, non-limiting embodiment of a microstrain-inducing manifold member  624  for use with a reduced-pressure wound treatment system, such as the reduced-pressure wound treatment system  100  in  FIG. 1 , is shown. A microstrain-inducing manifold may be formed by a plurality of microstrain-inducing manifolds  624 . Each microstrain-inducing manifold member  624  has one or more shaped projections  626  extending from a surface  631 . Unlike the reduced-pressure wound treatment system  100  of  FIGS. 1-3B , the microstrain-inducing manifold members  624  are not interconnected by a network of connecting members. Rather, a plurality of microstrain-inducing manifold members  624  may be poured into a wound whereby they work together to form the microstrain-inducing manifold in the wound (in situ) and whereby the shaped projections  626  of the microstrain-inducing manifold members  624  contact the wound to create microstrain therein. The plurality of microstrain-inducing manifold members  624  may fill the entire wound. Alternatively, the plurality of microstrain-inducing manifold members  624  may partially fill the wound, and, optionally, an alternative manifold may be placed atop the microstrain-inducing manifold members  624  to fill the wound. 
         [0063]    In another alternative, the microstrain-inducing manifold members  624  may have a coating of material that allows the microstrain-inducing manifold members  624  to fuse or sinter in situ to one another and form a single, integral manifold. Non-limiting examples of coatings include the following: any water soluble, swellable, or softenable material, including polymers such as poly vinyl alcohol and its copolymer, polyvinyl pyrrolidone and its copolymers, polyethylene oxide and its copolymers, polypropylene oxide and its copolymers, hydroxyl, carboxyl, and sulphonyl containing polymers (e.g., hydroxyl ethyl acrylate, carboxyl methyl cellulose, acrylamido methyl propane sulphonic acid and its salts), alginates, gums (e.g. xanthan and guar), other hydrogels and hydrocolloids. 
         [0064]    Although the present invention and its advantages have been disclosed in the context of certain illustrative, non-limiting embodiments, it should be understood that various changes, substitutions, permutations, and alterations can be made without departing from the scope of the invention as defined by the appended claims. It will be appreciated that any feature that is described in a connection to any one embodiment may also be applicable to any other embodiment.

Technology Category: a