WOUND DRESSING

Abstract

The present invention relates to a wound dressing, suitable for use in negative pressure wound therapy, comprising a body of porous material, the body of porous material comprising a plurality of cuts which provide regions of flexibility within the body. The present invention further relates to a method of manufacturing such wound dressings and to methods of its use.

Claims

1-26. (canceled)

27. A wound dressing apparatus for use in negative pressure wound therapy, the wound dressing apparatus comprising: a flexible sheet; a body of porous material covered by the flexible sheet, the body of porous material comprising a plurality of slits which provide regions of flexibility within the body, wherein the plurality of slits comprise two or more parallel linear series of slits, wherein a spacing between adjacent linear series is regular, and wherein the plurality of slits pass only partially through a thickness of the body; and a tube configured to supply negative pressure to under the flexible sheet.

28. The wound dressing apparatus of claim 27, further comprising a source of negative pressure connected to the tube.

29. The wound dressing apparatus of claim 28, wherein the source of negative pressure comprises a vacuum pump.

30. The wound dressing apparatus of claim 27, wherein the plurality of slits pass at least halfway through the thickness of the body.

31. The wound dressing apparatus of claim 27, wherein the plurality of slits pass at least three quarters through the thickness of the body.

32. The wound dressing apparatus of claim 27, wherein the plurality of slits comprise a first set of slits extending in a first orientation, and a second set of slits extending in a second orientation perpendicular to the first orientation.

33. The wound dressing apparatus of claim 31, wherein the first set of slits comprise two or more parallel linear series of slits extending in a first direction, and the second set of slits comprise two or more parallel linear series of slits extending in a second direction perpendicular to the first direction.

34. The wound dressing of claim 33, wherein the first set of slits intersect with the second set of slits.

35. The wound dressing of claim 27, wherein the plurality of slits comprise a first set of slits and a second set of slits, the first set of slits intersecting with the second set of slits.

36. The wound dressing of claim 27, wherein the plurality of slits do not render portions of the body of porous material frangible.

37. The wound dressing of claim 27, wherein the body of porous material comprises foam.

38. The wound dressing of claim 37, wherein the foam comprises a porosity between about 30-60 ppi.

39. The wound dressing of claim 37, wherein the foam comprises a mean pore diameter ranging from 300-800 μm.

40. The wound dressing of claim 27, wherein the plurality of slits comprise an average length of about 10 mm to 70 mm.

41. The wound dressing of claim 40, wherein the plurality of slits comprise an average length of about 20 to 50 mm.

42. The wound dressing of claim 41, wherein the plurality of slits comprise an average length of about 30 mm.

43. The wound dressing of claim 27, wherein the plurality of slits comprise a plurality of gaps between slits, the gaps comprising an average distance between slits that is at least 5 times an average pore diameter.

44. The wound dressing of claim 27, wherein the body of porous material comprises a thickness from about 10 mm to 50 mm.

45. The wound dressing of claim 44, wherein the body of porous material comprises a thickness from about 15 mm to 40 mm.

46. The wound dressing of claim 45, wherein the body of porous material comprises a thickness of about 15 mm.

Description

[0038] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0039] FIG. 1 shows an array of blades adapted to form slits in a body of a wound dressing material according to the present invention;

[0040] FIG. 2 shows a body according to the present invention curved in a first direction;

[0041] FIG. 3 shows a body according to the present invention curved in a second direction;

[0042] FIG. 4 shows a comparison of a body of foam according to the present invention with an un-cut body of foam;

[0043] FIG. 5 shows a second array of blades adapted to form cuts in a body of a wound dressing material according to the present invention;

[0044] FIG. 6 shows, a body according to the present invention cut with the array of blades of FIG. 5; and

[0045] FIG. 7 shows the body of FIG. 6 curved in two dimensions.

[0046] An array of blades (10) mounted on a board is shown in FIG. 1. Each blade (12) is a straight thin blade 30 mm long, and having a depth of approximately 30 mm. The blades are arranged in 20 parallel linear series of blades (16,18), each series comprising a row of blades (12) arranged longitudinally, with a gap (14) of 3 mm between each blade (12) in the series. Each series is spaced from the adjacent series by a 3 mm spacing (15). Furthermore, adjacent series (16,18) are staggered relative to one another such that the gap between the blades on one series (16) aligns with the midpoint in the adjacent series (18). Accordingly, the blades within the array (10) are arranged like the bricks in a wall. Given this offset arrangement, it is convenient that at the end of a series where a full 30 mm blade would extend beyond the dimension to be cut, blades of 15 mm length are provided; this allows for a neater array—once more, this is akin to half bricks at the end of a row in a wall. Full length blades could be used at the ends, provided they would not be problematic in the cutting process.

[0047] A body of NPWT foam (20) measuring 200×125×30 mm is cut using the array (10). It is cut by driving the array of blades (10) through the body (20) in a die cutting operation. This can be achieved using a press, typically a hydraulic press (not shown), also known as a clicker press. The blades are driven perpendicularly into and through the largest face of the body (20), and perpendicular thereto, to form a plurality of slits therein. The slits (21) formed are arranged in a plurality of parallel linear series (26,28) of slits, each comprising slits (21) 30 mm long separated by gaps (22), where material is left un-cut, which are 3 mm long. Each series is separated by a spacing (24) 3 mm in width. When the body (20) is curved, as shown in FIG. 2, the slits (21) open up to form a lattice structure. Tension in the outer region of the body (20) as a result of the curving process is relieved through deformation of the body (20) which is facilitated by the slits (21) provided therein. The arrangement of parallel offset linear series of linear slits is particularly suited to this as it form a regular lattice structure, as shown in FIG. 2.

[0048] In the embodiment shown in FIG. 2, an additional partial cut (30) has been made running the length of the middle of the largest face of the body (20), perpendicular to the slits. This allows the body (20) to be easily split in two if this is desirable.

[0049] FIG. 3 shows another body (40) cut using the array of blades of FIG. 1, this time without the additional cut (30). The body has been curved in a different manner to that in FIG. 2. In this case the body has been bent back on itself along its longest side, i.e. the 200×300 mm face has been curved back on itself. The body (40) has opened via the slits (42) into an open lattice structure. This type of curving of the body (40) is not generally useful for a wound dressing application, but does serve to demonstrate the flexibility and strength of the body (40).

[0050] FIG. 4 further demonstrates the ability of a body according to the present invention (40) to drape over a surface, in this case a leg, when compared to an uncut body (46).

[0051] FIG. 5 shows an array (50) of blades adapted to form cuts in a body of foam in two orientations, the orientations being perpendicular to each other. As with the array (10) in FIG. 1, the blades have a depth of 30 mm. However, in the array (50) comprises H-shaped blades (52) comprising a first blade element 30 mm long (54) (also termed “cross-piece”), with second (56) and third (58) blade elements (also termed “sides”) 15 mm long located at the end of the first blade element (54), each end of the first blade element intersecting with the midpoint of the second and third blade elements, thus defining a “wide H-shaped” blade. The array is made up of first set of eleven parallel linear series of H-shaped blades in a first orientation (called X for convenience) and a second set of eleven parallel linear series of H-shaped blades in a second, perpendicular orientation (called Y for convenience). Adjacent series within each set are offset in exactly the same manner as for linear blades. As can be seen from FIG. 5, the blades are spaced and arranged such that a close packing of the blades as achieved, but each blade is always approximately 5 mm or so from the nearest neighbouring blade. It can be seen that the “side” of a blade in the X-orientation nests within the region defined by the “cross-piece” and “sides” of a blade in the Y-orientation. Such an array is suited to forming slits in a body to allow draping in two planes.

[0052] FIG. 6 shows a body (60) formed by cutting with the array of FIG. 5. The slits (62) are formed by pressing the array of blades (50) through the body (60) in the same manner as described above. H-shaped slits (62) are formed in the body (60) corresponding to the array of blades (50). As shown in FIG. 7, the body (60) is well adapted to curving in complex shapes.

[0053] It should be noted that the present description has focussed on bodies formed by a batch die cutting process. There are of course numerous ways of forming cuts in a body of porous material (e.g. laser cutting, high pressure liquid cutting), or the cuts could formed when the body itself is formed (e.g. during a moulding process). Furthermore, these methods could be applied in a flow process rather than a batch; this might be more efficient for large production runs. All such variations are within the scope of the present invention.

[0054] Furthermore, it should be noted that, while the exemplified embodiments form particularly preferred embodiments with excellent drapeability, it is quite possible that other arrangements of cuts will provide satisfactory results.