HK1100020A - Wound contact device - Google Patents

Description

Wound contact article

RELATED APPLICATIONS

This application claims priority from U.S. provisional patent application No. 60/561,745, filed 4/13/2004, the contents of which are incorporated herein by reference.

Technical Field

The present invention relates to an article and method for treating wounds. More particularly, the present invention relates to a contact article for treating wounds.

Background

Wound healing is a basic human rehabilitation process. It has long been known that the application of suitable materials to wounds aids the natural regeneration process of the body. Historically, these materials have been made from cotton fibers; such as gauze. These dressings are beneficial to the healing process because they isolate damaged tissue from external contaminants and they remove potentially harmful wound exudate.

Many studies have concluded that wound healing depends on the interplay of complex mechanisms involving cell proliferation, migration, adhesion, and angiogenesis. Application of traditional gauze or other substantially flush materials is not substantially optimal for these mechanisms. Wound healing studies in vitro are performed in cell culture media that ensure cell function. Therefore, in the study of wound healing, it is desirable to provide cell culture equivalents or bioreactor systems to optimize the interaction of the proliferation, migration and adhesion functions of cells. In addition, other bodily functions must be added, wherein the functions promote the supply of fibronectin, plasma proteins, oxygen, platelets, growth factors, immunochemicals, and the like.

As science and medicine have advanced, the technology incorporated into wound healing devices has improved dramatically. Highly absorbent wound dressings capable of absorbing many times their own weight of liquid are used. Systems have been obtained that temporarily seal the wound and utilize suction to drain exudate. Dressings incorporating antibacterial and biological healing agents have also been used. Articles that provide a moist wound environment to promote healing have found use.

Despite some technical achievements in wound healing products and dressings, not a few suffer from the pain associated with chronic wounds. These chronic wounds are debilitating and can last for years, greatly reducing the quality of a person's life. These wounds often lead to amputation. Individuals may even die from complications such as infection.

Therefore, there is a strong need for more effective wound healing articles and methods.

Disclosure of Invention

In order to promote healing of a wound, the present invention provides a wound contact material, a method for manufacturing the wound contact material and a treatment method using the wound contact material.

According to an exemplary embodiment of the present invention, a therapeutic device for promoting wound healing in a mammal is provided. The article comprises a permeable substrate or structure having a plurality of recesses formed in a surface thereof, wherein said surface having said recesses is positioned in surface contact with the wound.

According to another exemplary embodiment of the present invention, a therapeutic device for promoting wound healing in a mammal is provided. The device includes a permeable structure having a plurality of wound surface contact elements disposed between ends of the structure and having a plurality of voids defined by the contact elements.

According to yet another exemplary embodiment of the present invention, a therapeutic device for promoting the healing of a wound in a mammal is provided, the device comprising a permeable structure comprising a plurality of fibers coupled to one another, wherein the structure has a plurality of wound surface contact elements disposed between ends of the structure and a plurality of voids defined by the contact elements.

In accordance with yet another exemplary embodiment of the present invention, a therapeutic device for promoting the healing of a wound in a mammal is provided, the device comprising a polymeric mat having a plurality of wound surface contact elements disposed between ends of a structure and a plurality of voids defined by the contact elements.

According to yet another exemplary embodiment of the present invention, there is provided a method of manufacturing a therapeutic device for promoting the healing of a wound in a mammal, comprising the steps of: providing a molten matrix material; providing a mold defining and forming a plurality of recesses and a plurality of contact elements; and applying (applying) the molten matrix material to the mold.

According to a further exemplary embodiment of the present invention, there is provided a method of manufacturing a therapeutic device for promoting the healing of a wound in a mammal, comprising the steps of: providing a permeable structure; and forming a plurality of recesses in a surface of the permeable structure.

According to another exemplary embodiment of the present invention, there is provided a method of treating a wound, comprising the steps of: providing a permeable structure, wherein the structure comprises a plurality of wound surface contact elements disposed between ends of the structure and a plurality of voids defined by the contact elements; applying a permeable structure to at least one surface of the wound; and applying a force to the structure to maintain the structure in intimate contact with the wound surface.

The above-described, as well as other aspects and objects, will become apparent in the following description.

Drawings

The present invention is best understood from the following detailed description when read with the accompanying drawing figures. It is emphasized that, according to common practice, the various features of the drawings are not to scale. Rather, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Wherein the drawings comprise:

fig. 1 is a perspective view of a channeled wound contact dressing according to a first exemplary embodiment of the present invention;

FIG. 2A is a perspective view of a channeled wound contact assembly according to a second exemplary embodiment of the present invention;

FIG. 2B is a cross-sectional view of a channeled wound contact assembly according to the second exemplary embodiment shown in FIG. 2A;

fig. 3A is a perspective view of a dimpled wound dressing according to a third exemplary embodiment of the present invention;

FIG. 3B is a top view of the dimpled wound dressing shown in FIG. 3A;

FIG. 3C is a bottom view of the dimpled wound dressing of FIG. 3A;

FIG. 3D is a cross-sectional view of the dimpled wound dressing shown in FIG. 3A;

4A, 4B, 4C illustrate the use of a dimpled wound dressing as shown in FIG. 3A;

fig. 5A is a perspective view of an irregular wound contact dressing according to a fourth exemplary embodiment of the present invention;

fig. 5B is a cross-sectional view of the irregular wound contact dressing of fig. 5A.

Detailed Description

A wound dressing with an interrupted contact layer has the advantage of promoting tissue growth under the influence of a wound surface contact element and enabling tissue growth by providing a void volume at the interruption for subsequent tissue growth. Ideally, the structure of the contact material is sufficiently physically corrugated to resist flattening when forces are applied to the material required to press the material against the wound surface.

The material desirably is capable of retaining its structure when exposed to aqueous or other bodily fluids. Many conventional sheet materials soften when exposed to moisture, causing a change in their geometry. The contact layer is permeable, allowing the underlying wound to breathe and allowing drainage of the wound. The absorbency of the contact layer should not be too great as it can lead to structural damage. The layer is composed of a base material that is resistant to the occurrence of changes in the presence of moisture and aqueous liquids.

In the present embodiment, the size of the void remaining on the wound surface is preferably at least 0.1mm when the structure is pressed onto the wound surface. The width of the void defined by the contact elements adjacent to the void is preferably greater than 0.1 mm. More preferably between about 0.5 and 10mm wide and more preferably between about 0.2 and 5mm high.

Wound healing is considered to be a complex process. When a wound contact material as described is pressed against the surface of a wound, it is believed that some biological processes occur. Mechanical stress is applied to the underlying tissue. Discontinuities in the contact surface will cause catenary shape (catenary shape) forces to stress the tissue. These mechanical stresses promote cellular viability and angiogenesis, while the discontinuities begin to be filled with granular tissue (granules). Excess fluid is transferred from the wound and the tissue grows in a manner and pattern that minimizes damage to newly growing tissue after removal of the contact surface.

The fiber matrix or structure has various flexibility brought by the spinning process technology. The fabric may be formed into the structural member for use in the present invention by any number of methods known in the art. Among these methods are knitting, weaving, embroidering, knitting, felting, spunbonding, meltblowing, and meltspinning. Each of these methods can be further adapted to produce materials with structures that match the structures of the materials of the present invention. For melt-blowing processes, the desired structure can be obtained during the production of the structural part by, for example, spraying the molten material directly onto a mold. Alternatively, the structure may be made by machining the formed structural member after production, for example by hot stamping or vacuum forming. In addition, the fibers may be mixed with a binder and sprayed onto the textured surface.

The versatility of the fiber fabric also extends to its easy adaptability for combined applications. The individual fiber materials may be varied to optimize physical parameters such as stiffness or flexibility. The monofilament material may also be selected for its known properties of assisting wound healing. Examples of these fibrous materials are calcium alginate and collagen. Alternatively, the fibers may be treated with known wound healing agents, such as hyaluronic acid or antimicrobial silver (antimicrobial silver). The ratio of fibrous materials may be varied to suit the needs of the wound. According to a desirable aspect of the present invention, different fibers having a variety of wound healing properties may be added as desired.

Other fibrous structures contemplated as beneficial additives include:

1. fluid-absorbent fibers

2. Non-absorbent fibers

3. Bioabsorbable fiber

4. Wicking fiber for drainage of wound surfaces

5. Fibres with a known healing action, e.g. calcium alginate

6. Bioerodible fibers for controlled release of curing agents

7. Conductive fibers for transporting electrical charge or current

8. Adhesive fibers for selectively removing undesirable tissue, material or microorganisms

9. Non-adhesive fibers for protecting delicate tissues

Fig. 1 shows an exemplary embodiment of the present invention. As shown in fig. 1, channeled wound dressing 100 is comprised of a generally conformable polymeric felt material 102. Alternative fabrics may also be suitable for most applications, such as knitted, woven or braided fabrics. Polyolefins such as polyethylene or polypropylene and polyurethanes such as nylon having similar physical properties are also contemplated. Particularly desirable is the creep resistance that polymers possess. Void channels 104 are cut into the mat material 102 to provide discontinuities that promote the upward growth of new tissue. In use, channeled wound dressing 100 is pressed onto a wound in intimate contact with the injured tissue. Ideally, a force of 0.1psi or greater is applied to the contact layer to press the contact element against the wound surface. Wound contacting element 106 is thus in intimate contact with the injured tissue.

Figures 2A and 2B show wound dressing assembly 200 comprised of channeled dressing 100 and a moisture vapor permeable adhesive backsheet 202. Generally, adhesive moisture vapor permeable backsheets are well known in the art and are believed to aid in wound healing by maintaining optimal moisture content relative to certain specific wounds. In use, dressing assembly 200 is placed on the surface of a wound with its channeled dressing portion 100 in contact with the wound. Adhesive sheet 202 covers channeled dressing 100 and adheres to the skin adjacent the wound. Assembly 200 provides the advantages of channeled dressing 100. Additionally, the adhesive sheet 202 secures the assembly 200 and protects the wound from bacterial infection and the like while enabling moisture vapor transmission.

Fig. 3A, 3B, 3C and 3D show another satisfactory embodiment of the present invention. The substrate or structure for dimpled wound dressing 300 may be constructed of materials similar to those utilized in channeled dressing 100 and in a similar production method. Figure 3A depicts a perspective view of dimpled dressing 300 with contact surface 320 positioned thereon. Figure 3D shows a cross-sectional view of dimpled dressing 300, which best illustrates a plurality of contact elements 332 and dimple voids 330. Preferably, the total dimple void area occupies at least 25% of the total dressing area. More preferably, the total dimple void area comprises at least 50% of the total dressing area. Dimple voids 330 are partially defined by sidewalls 332. Sidewalls 332 serve to provide, in part, the rigidity required to resist compaction of female dressing 300. Preferably, the contact element is configured to have an arcuate contact surface. In a preferred embodiment, the contact radius (radius of contact) is between about 0.1mm and 1 mm.

Dimple voids 330 can be formed in a variety of regular or irregular shapes. Preferably, the pocket void is configured such that it is not an "undercut" such that the perimeter of each orifice is smaller than the perimeter of the respective inner void. The "undercut" or reticulated void structure can cause tissue disruption when dressing 300 is removed, as any tissue that has grown into the void is torn away when the material is removed from the wound. Additionally, undercut or reticulated void structures are more likely to result in shedding of the dressing material into the newly growing wound tissue.

In a preferred embodiment, the base material for dressing 300 is Masterflo RTM, manufactured by BBA group of Wakefield, Mass., USA. In this exemplary embodiment, the thickness of the base material is approximately 1.0 mm. Dimple voids 330 are hot stamped into the base material to a depth of about 0.75mm and a diameter of about 2 mm.

Since the contact layer is typically replaced every few days, it is important to account for the possibility of aligning newly formed tissue with the interstices of a new contact layer. Thus, according to an exemplary embodiment of the invention: 1) the dimple voids 330 can be randomly arranged so that the dimple voids 330 do not line up with new tissue growths each time the dressing is replaced; 2) different contact layers with recesses of different diameters may be provided; or 3) different spacing of the wells may be used each time the material is changed.

Figures 3B and 3C show top and bottom views, respectively, of dimpled dressing 300. A variation of this embodiment is also envisioned having dimple voids 330 and/or contact elements 322 disposed on both the top and bottom of dimpled dressing 300. A second variation on dimpled wound dressing 300 is also envisioned in which some or all of the dimple voids 330 are replaced by holes through the entire thickness of the structure, such that the top and bottom views of this variation would look like the view shown in fig. 3B.

In an exemplary embodiment, dimple voids 330 can be partially filled with a therapeutic substance. For example, a biocidal substance may be placed in the void 330 to treat an infected wound. In addition, a biological healing agent may be delivered into the void to increase the rate of formation of new tissue. In yet another exemplary embodiment, the layers of dressing 300 may have different functions on each side. For example, one side of dressing 300 may be optimized for the growth of new tissue, while the other side may be optimized for the delivery of antimicrobial agents.

The use of dimpled dressings is illustrated in figures 4A, 4B and 4C. Fig. 4A shows a wound surface 400. Note that wound surface 400 may represent a small interior portion of a deep tissue wound, or a majority of a shallow surface wound. Figure 4B shows application of dimpled dressing 300 to wound surface 400 and corresponding tissue growth 410 in dimple voids 330. Finally, in FIG. 4C, dressing 300 with the dimpled hole is shown removed leaving only tissue growth 410. As will be discussed in detail below, it is desirable to provide an external force for maintaining dressing 300 pressed against the wound surface.

Figures 5A and 5B show another embodiment of the present invention, a rough irregular dressing 500. Referring to the perspective view, figure 5A depicts an irregular dressing 500 having irregular voids 510 and irregular contact surfaces 520, wherein the contact surfaces 520 act as "hook" elements that are capable of contacting and adhering to necrotic tissue when the substrate is placed in a wound. When the matrix is removed from the wound, necrotic tissue may be removed from the wound as it adheres to the hook-shaped protrusions 520. Removal of the matrix removes the wound. The removal of necrotic tissue is an important part of healing a wound. The matrix of the dressing 500 may be made of a polymer felt or batting (batting). In an exemplary embodiment, the mat is charred with hot air so that a percentage of the fibers melt to form a textured surface with some hook elements 520. Another suitable configuration may be hook material, such as used with hook or loop fabric.

While the method and matrix used facilitate the growth of new tissue, after proper removal of necrotic tissue, the wound is still infected and may be treated with substances, such as those including antimicrobial silver, which function to kill bacteria.

Generally, the wound healing phase of new tissue formation is referred to as the proliferative phase. Once the wound has sufficiently healed and the bacterial load has sufficiently decreased during the proliferation phase, a matrix free of antimicrobial silver and optionally containing growth promoting material may be used to facilitate the continued proliferation of new cell tissue.

Figure 5B shows a random cross-section of irregular dressing 500. The roughened surface of the irregular dressing 500 can be made by passing a suitable substrate under convective heat at or near the melting point of the constituent materials of the substrate. For example, the polymeric material typically melts in a range from about 250 degrees celsius to about 290 degrees celsius. A polymer mat material operating in this range that passes briefly under a convective heat source will undergo surface melting and subsequent fusing of the polymer strands on its surface. The degree of surface melting can be controlled by temperature and exposure time to produce a surface having a desired roughness that exhibits irregular voids 510 and irregular contact elements. Although irregular dressing 500 is shown with only one roughened surface, the invention is not so limited as both the upper and lower surfaces may be similarly roughened. Such a dressing would be quite useful in treating an impaired wound.

As noted above, treatment with the present wound bandage invention involves pressing the inventive bandage into intimate contact with the wound surface. Typically, the force should be at least 0.1 psi. Various methods and systems for maintaining the close contact state are conceivable. These methods and systems may include: attaching an adhesive film to the inventive bandage and adjacent to the wound surface; wrapping the bandage over the dressing and around the injured area; and securing the air bag or other inflatable bladder to the structure to inflate the bladder with a gas or liquid. In an exemplary embodiment, pressure is applied to the bladder intermittently. The conformable seal may be placed over the wound and brought into contact with the structure, and then the rigid seal is secured over the wound and brought into contact with the structure, thereby transferring force to the contacting structure. Pressure is then applied between the rigid seal and the flexible seal to press the contact structure against the wound surface. Intimate contact may be enhanced by sealing the wound area with a conformable shield while applying suction. Dimpled wound dressing 300 is particularly well suited for such applications when suction is used. Typically, the amount of suction ranges between 0.25PSI and 5 PSI. The use of suction may be further improved by packing the wound packing material onto the back of the dressing. One such suitable wound packing material is described in U.S. provisional patent application No. 60/554,158, filed 3/18/2004.

Example analysis 1

Patient A, 70 years old, male, second-level bedsore of right hip, obvious ulceration. The contact structure of the invention is applied to the wound, and an adhesive film is placed over the wound and in contact with the structure. Suction was applied at 1.1psi under the adhesive film to transfer the force to the contact structure. The suction force is maintained substantially continuously. The contact material was changed every two to four days. After 30 days of use of the device, the ulcerated portion of the wound was substantially healed and the open area of the wound was reduced from 66 square centimeters to 45 square centimeters. Performing multi-layer skin transplantation on the wound.

Example analysis 2

Patient B, 50 years old, male, had a fracture (failure) of the right ankle, exposing the bone. A plate was used for fracture reduction and a free rectus abdominis flap treatment was performed covering the exposed bone and hardware (hardware). The flap only partially survives, resulting in an open wound with exposed bone and hard material. The contact structure of the invention is applied to the wound and an adhesive film is placed over the wound and in contact with the structure. The force is applied to the contact structure by wrapping an excellent bandage around the ankle, or by the application of suction. Typically, suction is applied for about half a day and the force of the bandage wrap is maintained for the remainder of the day, several days later, only the bandage wrap is used to provide the force. When the force is provided by suction, a suction force of between 1 and 2psi is used. In less than two weeks, new tissue has grown on the exposed hard objects. The wound area was reduced from 50 square centimeters to 28 square centimeters over a 7 week period.

While preferred embodiments of the present invention have been shown and described herein, it will be understood that these embodiments are provided by way of example only. Numerous variations, modifications, and alternatives can be devised by those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the scope and spirit of the invention.

Claims (42)

1. A therapeutic device for promoting the healing of a wound in a mammal, said device comprising:

a permeable structure having a plurality of recesses formed in a surface thereof;

wherein the surface having the plurality of recesses is positioned in contact with at least one surface of the wound and the structure is substantially maintained in a predetermined configuration at least in the presence of fluid in the wound.

2. The article of claim 1, wherein the structural member comprises a synthetic polymer.

3. The article of claim 2 wherein the synthetic polymer comprises a polyolefin.

4. The article of claim 3, wherein the polyolefin is one of polyethylene or polypropylene.

5. The article of claim 2 wherein the synthetic polymer comprises polyurethane.

6. The article of claim 4 wherein the polyurethane is nylon.

7. The article of claim 2 wherein the synthetic polymer comprises a polyester.

8. The device of claim 1 wherein the structure comprises a textile material.

9. The article of claim 1, wherein the structure comprises a knitted material.

10. The device of claim 1 wherein the structure comprises a woven material.

11. The article of claim 1, wherein the structure comprises an embroidered material.

12. The device of claim 1 wherein the structural member comprises a felt material.

13. The article of claim 1 wherein the structural member comprises a spunbond material.

14. The article of claim 1, wherein the structure comprises a meltblown material.

15. The device of claim 1 wherein the structure comprises a melt spun material.

16. The article of claim 1, wherein the structural member comprises a fibrous material comprising at least one fiber.

17. The article of claim 16, wherein the fibers further comprise a healing agent.

18. The article of claim 17, wherein the healing agent is at least one of hyaluronic acid and/or antimicrobial silver.

19. The device of claim 16 further comprising a second fiber comprising a healing material selected from the group consisting of collagen and calcium alginate.

20. The article of claim 1 further comprising an adhesive film attached to at least a portion of the permeable structure.

21. A therapeutic device for promoting the healing of a wound in a mammal, said device comprising:

a permeable structure having:

a plurality of wound surface contact elements disposed between the ends of the structure,

and a plurality of voids defined by the contact elements,

wherein the structure is substantially maintained in a predetermined configuration, at least in the presence of fluid in the wound.

22. The article of claim 21, wherein the structure comprises a first side having a first surface area and a second side having a second surface area.

23. The article of claim 22, wherein the plurality of voids are disposed on at least one of the first side portion and/or the second side portion.

24. The article of claim 23, wherein the plurality of voids occupy an area greater than about 25% of the surface area of the side portion on which they are located.

25. The article of claim 23, wherein the plurality of voids occupy greater than about 50% of the surface area of the side portion on which they are located.

26. A therapeutic device for promoting the healing of a wound in a mammal, said device comprising:

a permeable structure comprising a plurality of randomly arranged fibers bonded to one another and having:

a plurality of wound surface contact elements disposed between the ends of the structure;

and a plurality of voids defined by the contact elements.

27. A therapeutic device for promoting the healing of a wound in a mammal, said device comprising:

a polymer mat having a plurality of wound surface contacting elements disposed between the ends of the structure; and

a plurality of voids defined by the contact elements.

28. A method of manufacturing a therapeutic device for promoting the healing of a wound in a mammal, comprising the steps of:

providing a molten matrix material;

providing a mold defining a plurality of recesses and a plurality of contact elements;

applying the molten matrix material to a mold;

cooling the molten matrix material; and

the shaped article is removed from the mold.

29. A method of manufacturing a therapeutic device for promoting the healing of a wound in a mammal, comprising the steps of:

providing a permeable structure; and

a plurality of recesses are formed in a surface of the permeable structure.

30. The method of claim 29, wherein the step of forming a plurality of recesses comprises hot stamping.

31. The method of claim 29, wherein the step of forming a plurality of recesses comprises vacuum forming.

32. The method of claim 29, wherein the step of forming a plurality of recesses comprises a stamping process.

33. The method of claim 29, wherein the step of forming a plurality of recesses comprises a cutting process.

34. The method of claim 29, wherein the step of forming the plurality of recesses comprises transmitting convective heat across at least one of the surfaces of the structural member, wherein the convective heat is at approximately a melting point temperature of a material of the structural member.

35. A method of treating a wound comprising the steps of:

providing a permeable structure comprising a plurality of fibers and having: i) a plurality of wound surface contact elements disposed between the ends of the structure; ii) a plurality of voids defined by the contact elements;

a permeable structure is applied to at least one surface of the wound.

36. The method of claim 35, further comprising the step of:

attaching an adhesive film to at least a portion of the permeable structure, the portion being opposite the contact element; and

the permeable structure is releasably held in intimate contact with the wound surface using an adhesive film.

37. The method of claim 35, further comprising the step of releasably maintaining the permeable structure in intimate contact with the wound surface using a bandage wrap.

38. The method of claim 35, further comprising the step of releasably holding the permeable structure in intimate contact with the wound surface using suction.

39. The method of claim 35, further comprising the step of releasably holding the permeable structure in intimate contact with the wound surface using the wound dressing.

40. The method of claim 35, further comprising the step of releasably retaining the permeable structure in intimate contact with the wound surface using an inflatable bladder.

41. A method of treating a wound comprising the steps of:

providing a first permeable structure comprising:

i) a plurality of wound surface contact elements disposed between the ends of the structure;

ii) a plurality of voids defined by the contact elements;

applying the first permeable structure to the wound such that at least a portion of the contact element engages a portion of the surface of the wound;

removing the first permeable structure from the wound after a predetermined period of time, along with at least a portion of the necrotic tissue attached to the plurality of elements of the contact element;

providing a second permeable structure comprising a pharmaceutical agent based on the wound condition; and

after a second predetermined period of time, the second permeable structure is removed from the wound.

42. The method of claim 41, further comprising the steps of:

a third permeable structure is applied to the wound, the third structure having a plurality of recesses formed in a surface thereof.