Abstract:
A placental tissue assembly for treating wounds or surfaces of a patient has one or more layers of placental tissue and a backing material. The one or more layers of placental tissue have a first side and a second side. The backing material is adhered to and covers one of either the first or second sides of the one or more layers of placental tissue to create the assembly. The assembly when applied onto a surface to be treated on the side of the tissue opposite the backing material adheres to the surface with an attachment force greater than an attachment force of the backing material adhered to the first or second side. This allows the backing material to be released leaving the placental tissue affixed to the surface to be treated.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to a placental tissue assembly for treating wounds or surfaces of a patient. The invention also provides an improved method of applying the placental tissue assembly. 
       BACKGROUND OF THE INVENTION 
       [0002]    Currently, placental tissue is used in various wound and skin tissue treatments to accelerate healing. The placental tissue can be prepared in various forms. One form involves creating layers or membranes of material that has been dried aseptically and packaged, the material being cut into thin squares or rectangles and sterilized for future application on wounds or skin tissue to be treated. 
         [0003]    The placental tissue has layers or membranes of chorion and amnion. These layers can be used together or separately or even combined with other layers to construct laminated multiple tissue layers of amnion or chorion or both. The dried layered material when applied is typically rehydrated prior to being applied. The processed placental tissue material when made into a single layer of amnion or chorion is extremely thin and translucent making it difficult to discern sides. An epithelial side is on one side and a stromal side is on an opposite side, distinguishing the two sides is difficult. 
         [0004]    U.S. Pat. No. 8,460,715 B2, assigned to Mimedx, teaches the layer or membrane can be embossed with indentations or bumps to indicate a top or bottom surface. In U.S. Pat. No. 8,597,687 B2; also assigned to Mimedx, there is a method of placing an asymmetric label on a portion of at least one side of the tissue graft in order to distinguish one side from another. In that patent, the label is also part of the membrane created by embossing or indenting. 
         [0005]    The present invention achieves this ability to discern sides, but in a completely different approach which is unique in that it also greatly facilitates handling of the tissue during treatment so applying the layer is achieved without wrinkling, folds or other issues commonly found in practice. The single layer placental or layer membranes when rehydrated has a tendency to cling to itself like thin plastic film used in wrapping meat, this causes wrinkles and reduces surface contact on the wound to be covered. The present invention, as described herein, solves these issues in a simple and very reliable manner. 
       SUMMARY OF THE INVENTION 
       [0006]    A placental tissue assembly for treating wounds or surfaces of a patient has one or more layers of placental tissue and a backing material. The one or more layers of placental tissue have a first side and a second side. The backing material is adhered to and covers one of either the first or second sides of the one or more layers of placental tissue to create the assembly. The assembly when applied onto a surface to be treated on the side of the tissue opposite the backing material adheres to the surface with an attachment force greater than an attachment force of the backing material adhered to the first or second side. This allows the backing material to be released leaving the placental tissue affixed to the surface to be treated. 
         [0007]    Preferably, the backing material has at least a portion extending beyond the side of the tissue. The backing material overlays the one or more layers of placental tissue and extends beyond an outer edge of the one or more layers. The one or more layers have one or more outer edges and the backing material extends beyond the edges. 
         [0008]    In one embodiment, the backing material is permeable to liquids and wherein moistening of the backing material reduces the adherence to the first or second side of the one or more layers allowing the backing material to release from the one or more layers. In another embodiment, the backing material is an open mesh or net releasably adhered to one or more layers. 
         [0009]    In all embodiments, the assembly is made to be conformable to the surface. The surface can have a shape or a contour to which the one or more layers are to be applied. The placental tissue assembly can have the one or more layers made of amnion layers. It can have a single layer of amnion. Alternatively, the one or more layers can be chorion layers. It can be a single layer of chorion. Alternatively, the one or more layers can be made from micronized placental tissues, wherein the micronized placental tissue is amnion or chorion or combinations thereof. The micronized particles can be layered onto one side of a bioabsorbable membrane or layer similar to grit on sandpaper. The backing material  14  adhered to a side opposite the micronized particles. 
         [0010]    The placental tissue assembly of claim  1  wherein the one or more layers are amniotic membranes and the first side or second side not adhered to and opposite the backing material is a stromal side and the side against and adjacent the backing material is an epithelial side. The placental tissue assembly can also have the first or second side opposite the backing material with a releasable peel-off cover attached. The releasable peel-off cover can be cut or formed as two pieces with abutting edges wherein the abutting edges lift from the attached position on bending of the placental tissue assembly to facilitate peeling from the assembly. A method of applying one or more layers of placental tissue to a wound has the steps of providing the one or more layers adhered to a releasable backing material as an assembly; applying the assembly to the wound; and peeling or pulling the releasable backing material from the one or more layers of placental tissue, the one or more layers remaining attached to the wound. The method preferably further has the step of applying the assembly to a wound or surface to be treated and then moistening the backing material to facilitate release from the one or more layers. When the assembly has a peelable cover on a side of the placental tissue opposite the side adhered to the backing material and the method further has the step of removing the cover prior to applying the assembly to the wound. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention will be described by way of example and with reference to the accompanying drawings in which: 
           [0012]      FIG. 1  is a perspective view of the placental tissue assembly made in accordance with the present invention. 
           [0013]      FIG. 2  is an exploded view of the present invention. 
           [0014]      FIG. 2A  is the placental tissue assembly shaped as a square assembly. 
           [0015]      FIG. 2B  is the placental tissue assembly shaped as a round or circular assembly. 
           [0016]      FIG. 3  is an alternative embodiment of the placental tissue having a releasable peel-off cover. 
           [0017]      FIG. 4  is another alternative embodiment wherein the backing material is a net or open mesh material. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    With reference to  FIGS. 1 and 2 , a perspective view of the placental tissue assembly is shown. The placental tissue assembly  10  has a placental membrane layer  12  affixed to a backing material  14 . As shown in  FIG. 2 , the placental tissue  12  can have one layer  12 A or more layers,  12 A,  12 B,  12 C laminated together. The placental tissue has an outer side  20  and an inner side  22 . The inner side  22  is adhered to a surface of the backing material  14 . The backing material  14  can be sized identical or the same as the placental tissue  12 , as shown in  FIG. 3 . In such a configuration, the backing material  14 , after the placental tissue  12  is pressed onto the wound, must be easily released from the placental tissue  12 . One way this is accomplished is by moistening the backing material  14  so it can slip relative to the placental tissue  12  and be lifted off. The placental tissue  12  as shown has the one or more layers cut in a rectangular shape that is sized slightly smaller than the rectangular area of the backing material  14 . As shown, the placental tissue  12  has boundary edges or edges  30  around the perimeter of the tissue layers  12 A,  12 B,  12 C. The backing material  14  has an edge  40  that extends beyond the edge  30 . As shown, it is preferable that at least one edge  40  of the backing material  14  extend beyond the tissue  12 . As shown, all four edges  40  are shown overlapping and extending beyond the edges or boundaries  30  of the layers  12 A,  12 B,  12 C. It is understood that the placental tissue  12  can be provided as a single layer of material using  12 A only or can be laminated together as illustrated having multiple layers, one or more layers in combination with the backing material  14  are required to make the placental tissue assembly  10 . 
         [0019]    With reference to  FIGS. 2A and 2B , the placental tissue assembly  10  is shown in various exemplary shapes which can be square or circular, as illustrated in  FIGS. 2A and 2B  respectively. Otherwise, the assembly  10  is identical to that shown in  FIGS. 1 and 2 . The backing material  14  as shown, has a similar albeit larger shape, but could in fact be in any shape or size to overlap one side  20  or  22  of the placental tissue  12 . 
         [0020]    In an alternative embodiment, the placental tissue assembly  10  is shown with an additional releasable peelable cover or peel-off cover  16 ,  18 . As shown in  FIG. 3 , the peel-off cover  16 ,  18  is cut approximately midway through the surface area along cut abutting edges  19 , such that when attached to the side  20 , it covers the side  20  and provides additional protection for the tissue  12 . The placental tissue on side  22  as illustrated has the backing material  14  adhered to it. The side  20  can either be left unprotected and provided in a sterile package (not illustrated) or can have a releasable peelable cover or peel-off cover  16 ,  18  as illustrated in  FIG. 3 . To remove the cover  16 ,  18 ; the assembly can be bent slightly so the edges  19  lift from the side  20 . 
         [0021]    Placental tissue  12  can have an epithelial side and a stromal side, as illustrated. In the present embodiment, envision that the epithelial side is adhered to the backing material  14  and the stromal side is the side that will be attached to a wound or a surface to be treated with the placental tissue  12 . The placental tissue  12  can be amnion tissue or can be chorion tissue or can be a combination of chorion and amnion tissue. The placental tissue  12  can also have alternative layers assembled and affixed to the assembly  10  in a lamination, as illustrated in  FIG. 2 . 
         [0022]    In practice, when applying this placental tissue assembly  10  to a wound or surface, it is important that the backing material  14  be sufficiently pliable that the entire assembly  10  can be conformed about the wound or surface to be treated. After the wound or surface has been cleaned, the placental tissue assembly  10  can be laid over the surface and pressed lightly against the wound. In doing so, the assembly  10  is now adhered to the skin surface or wound tissue. Once adhered, it is now possible to wet the placental tissue assembly  10  and with a sponge or damp cloth to moisten the backing material  14  such that the placental tissue  12  attachment to the backing material  14  is reduced dramatically. When this occurs, the backing material  14  can simply be lifted at the edges and the underlying placental tissue  12  will remain firmly attached to the skin or wound tissue. The backing material  14  is a water permeable or absorbable paper or similar composition that will easily peel directly of the wet surface of the placental tissue  12 . In this embodiment, the placental tissue  12  is extremely improved in its method of application in that the placental tissue  12  can be a very thin membrane that would otherwise be very difficult to handle in the absence of a backing material. However, the backing material  14  provides enough support that the doctor or surgeon, when applying this placental tissue assembly  10  to the patient, can lay the entire assembly  10  on a wound and when pressed onto the wound, it will maintain an unwrinkled position until released from the backing material  14 . 
         [0023]    With reference to  FIG. 3 , an alternative embodiment is shown wherein the releasable or peelable cover  16 ,  18  is provided. When this occurs, an additional step is required when the placental tissue assembly  10  is taken from the sterile packaging, the nurse or doctor applying the tissue will slightly bend the assembly  10  so that the releasable material releases at the abutting edges  19  on each portion  16 ,  18  of the peelable cover. When this occurs, the edges  19  will lift slightly from the side  20  and be able to be easily peeled from the placental tissue  12 . Once removed, the placental tissue  12  can be applied to the skin or wound as previously discussed. 
         [0024]    With reference to  FIG. 4 , the backing material  14  as previously discussed can be provided as open mesh net  14 A that would be adhered to one side of the placental tissue  12 . In this embodiment, the open mesh net  14 A has minimal contact area with the placental tissue  12 , however, provides sufficient support that the placental tissue  12  will not wrinkle or deform during shipping, handling or during any procedure in treatment of a patient. In this embodiment, the adhesive forces between the open mesh net  14 A and the placental tissue layer  12  is such that the backing material  14  when formed as an open mesh net  14 A can be simply peeled from the placental tissue  12  without requiring any moisture. The procedure for application is very similar to the other embodiments; however there is no need for the additional step of moistening to create a release of backing material  14  from the placental layer  12 . In this embodiment, the placental tissue assembly  10  may have the dried layers  12 A,  12 B,  12 C rehydrated prior to attachment to the wound and the open mesh net  14 A can be peeled off in either a dried or moistened condition after attachment of the assembly  10  to the wound. In this alternative, the optional peel-off cover  16 ,  18  can also be used as discussed. 
         [0025]    With reference to the drawings, the illustrated thickness of the layers has been greatly exaggerated so the reader can appreciate and discern the features of the laminated placental tissue  12  when used in more than one layer. In reality, these layers have a thickness that approximates a standard sheet of paper which is about 0.05 mm thick. The tissue layer can vary from 0.01 mm to less than 1.0 mm, preferably 0.5 mm or less. The backing material  14  illustrated thickness is similarly exaggerated and is preferably about the thickness of standard paper or about 0.05 mm. It is understood these thicknesses can be varied in any size desired. The open mesh net  14 A backing material can be woven and its thickness can be greater, typically 0.5 mm or greater. 
         [0026]    Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described, which will be within the full intended scope of the invention as defined by the following appended claims.