Wound packing

Abstract

A wound packing material is provided, suitable for use in negative pressure wound therapy, including a body of a porous material, the body including frangible regions defining a plurality of portions, the frangible regions allowing the portions to be selectively removed from the body. Methods of manufacturing the wound packing material, and methods of its use are also provided.

Claims

1. A method of treating a wound, the method comprising: providing a wound packing material comprising a body of porous material, the body comprising a plurality of outer surfaces and a plurality of outer edges, each of the plurality of outer edges disposed at an interface of a pair of adjacent outer surfaces, each of the outer surfaces delimited by a subset of the plurality of outer edges, the body comprising frangible regions defining a plurality of portions, the frangible regions allowing the portions to be selectively removed from the body, wherein the frangible regions are arranged so that the body can be reduced in each of three orthogonal dimensions by removing a subset of the plurality of the portions at the frangible regions wherein the wound packing material comprises a first partial pre-cut that extends in a first direction from a first outer surface of the body to a second outer surface of the body, wherein the wound packing material comprises a second partial pre-cut that extends in the first direction from the first outer surface of the body to the second outer surface of the body, wherein each of the first and second partial pre-cuts is spaced apart from each outer edge of the subset of outer edges that delimits the first outer surface, and wherein the wound packing material comprises a third partial pre-cut that extends in a second direction from a third outer surface of the body to a fourth outer surface of the body, wherein the third partial pre-cut is spaced apart from each outer edge of the subset of outer edges that delimits the third outer surface; removing portions of the body of said wound packing material such that the body is a desired shape to fit within said wound; and packing the wound with said wound packing material.

2. The method of claim 1 further comprising: applying negative pressure to the wound.

3. The method of claim 2, wherein the wound packing material does not substantially collapse when negative pressure is applied to the wound.

4. The method of claim 2, wherein negative pressure is applied to the wound through the wound packing material.

5. The method of claim 2, wherein applying negative pressure comprises: providing a substantially fluid impermeable sheet over the wound and wound packing material, thereby defining a sealed volume; and delivering negative pressure to the wound from a vacuum source in fluid communication with the sealed volume to draw fluids from the wound.

6. The method of claim 5, wherein the fluids are drawn through the wound packing material.

7. The method of claim 2, wherein negative pressure is in the range of from 80 to 125 mm Hg below ambient atmospheric pressure.

8. The method of claim 1, wherein the body further comprises an upper surface, a lower surface, and a thickness defined therebetween, the body comprising at least one first partial pre-cut disposed within the thickness, an upper portion of the thickness being disposed between the at least one first partial pre-cut and the upper surface, a lower portion of the thickness being disposed between the at least one first partial pre-cut and the lower surface.

9. The method of claim 8, wherein the at least one first partial pre-cut is substantially parallel with the upper surface or the lower surface.

10. The method of claim 8, wherein the body further comprises at least one second partial pre-cut that is substantially perpendicular to the upper surface.

11. The method of claim 10, wherein the at least one second partial pre-cut is curved.

12. The method of claim 11, wherein the at least one second partial pre-cut comprises two or more spaced apart curved planar cuts that are substantially parallel with one another.

13. The method of claim 12, wherein the at least one second partial pre-cut comprises an additional curved planar cut that is non-parallel with the two or more spaced apart curved planar cuts.

14. A method of preparing a wound packing material, the method comprising: providing a wound packing material comprising a body of porous material, the body comprising a plurality of outer surfaces and a plurality of outer edges, each of the plurality of outer edges disposed at an interface of a pair of adjacent outer surfaces, each of the outer surfaces delimited by a subset of the plurality of outer edges, the body comprising frangible regions defining a plurality of portions, the frangible regions allowing the portions to be selectively removed from the body, wherein the frangible regions are arranged so that the body can be reduced in each of three orthogonal dimensions by removing a subset of the plurality of the portions at the frangible regions, wherein the wound packing material comprises a first partial pre-cut that extends in a first direction from a first outer surface of the body to a second outer surface of the body, wherein the wound packing material comprises a second partial pre-cut that extends in the first direction from the first outer surface of the body to the second outer surface of the body, wherein each of the first and second partial pre-cuts is spaced apart from each outer edge of the subset of outer edges that delimits the first outer surface, and wherein the wound packing material comprises a third partial pre-cut that extends in a second direction from a third outer surface of the body to a fourth outer surface of the body, wherein the third partial pre-cut is spaced apart from each outer edge of the subset of outer edges that delimits the third outer surface; and removing portions of the body of said wound packing material such that the body is a desired shape to fit within said wound.

15. The method of claim 14, wherein the body further comprises an upper surface, a lower surface, and a thickness defined therebetween, the body comprising at least one first partial pre-cut disposed within the thickness, an upper portion of the thickness being disposed between the at least one first partial pre-cut and the upper surface, a lower portion of the thickness being disposed between the at least one first partial pre-cut and the lower surface.

16. The method of claim 15, wherein the at least one first partial pre-cut is substantially parallel with the upper surface or the lower surface.

17. The method of claim 16, wherein the body further comprises at least one second partial pre-cut that is substantially perpendicular to the upper surface.

18. The method of claim 17, wherein the at least one second partial pre-cut is curved.

19. The method of claim 18, wherein the at least one second partial pre-cut comprises two or more spaced apart curved planar cuts that are substantially parallel with one another.

20. The method of claim 19, wherein the at least one second partial pre-cut comprises an additional curved planar cut that is non-parallel with the two or more spaced apart curved planar cuts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a body of porous wound packing material after being pre-cut in the x, y and z dimensions;

(3) FIG. 2 schematically shows the set of pre-cuts in the x and y dimension;

(4) FIG. 3 schematically shows the sets of pre-cuts in the z dimension;

(5) FIG. 4 shows a body with a single portion removed;

(6) FIG. 5 shows the body of FIG. 4 with a plurality of portions removed;

(7) FIG. 6 shows a first array of a set of blades suitable for forming a partial pre-cut in a first orientation in a body of wound packing material; and

(8) FIG. 7 shows a second array of sets of blades suitable for making second and third sets of partial pre-cuts in a body of wound packing material in second and third orientations;

DETAILED DESCRIPTION OF SOME EXEMPLIFYING EMBODIMENTS

(9) As shown in FIG. 1, a body 10 of porous material, such as foam, is generally a cube in shape having three dimensions, x, y and z. The porous material is suitable for wound packing. The material may be reticulated polyurethane foam of very high free internal volume. The body 10 could be a different shape, e.g. a comparatively flat cuboid, which is a conventional shape for foams for NPWT.

(10) As shown in FIG. 2, the body 10 is partially pre-cut by a suitable cutting technique, such as die cutting (though other techniques may be useable), in the planes in the x and y dimensions to define a first and second set of parallel planar partial pre-cuts 14, 16. The body 10 is also partially pre-cut in the z dimension to define a third set of parallel planar partial pre-cut 18. The three sets of partial pre-cuts 14, 16, 18 define individual cubic portions 12 of approximately equal volume.

(11) The three sets of partial pre-cuts 14, 16, 18 are intermittent, the gaps in the pre-cuts defining frangible regions 20 on each internal face of each portion 12 (in other words they are perforated for easy removal of the portions). The frangible regions 20 connect adjacent portions 12 together thereby to ensure the portions 12 remain connected together when the body 10 is stored, compressed or extended, i.e. when being used as a wound packing in NPWT.

(12) The frangible regions 20 extend between face sides of each portion 12 and are elongate. The thickness of each frangible region 20 is suitable to provide adequate strength to ensure adjacent portions 12 remain connected when the body 10 is being compressed or extended during normal use, whilst allowing one or more portions 12 to be easily pulled from the body 10 by compromising the integrity of the frangible regions 20 attaching the portion 12 to the body. For typical NPWT foams, a frangible region of approximately 2 mm of thickness provides a good compromise of strength versus tearability.

(13) One or more portions 12 can be selectively removed by hand from the body 10 to shape the body 10 for a particular wound packing application. Advantageously, cutting tools such as knives, scalpels and scissors are not required to shape the body 10 of porous material.

(14) As shown in FIGS. 4 and 5, the body 10 is a cube of volume 448000 mm.sup.3, which is pre-cut in the x, y and z dimensions to define 448 (i.e. 788) equally sized 1000 mm.sup.3 portions 12 (i.e. 101010 mm). Adjacent portions 12 are connected by a frangible portion 20 of 2 mm thick porous material (not shown).

(15) The frangible regions 20 ensure the body 10 retains its structural integrity for storage and handling purposes whilst allowing one or more portions 12 to be selectively removed therefrom. FIG. 4 shows a single portion 12 removed from the body 10 to leave a hole 22, whilst FIG. 5 shows a plurality of portions 12 removed from the body 10 to selectively shape the body 10 for a particular application of wound packing. The body 10 may be shaped to complement the external contours of a patient or to fit in a cavity.

(16) Of course, the dimensions of the body 10 and the portions 12 may be different to those described above for a particular application and the number and orientation of partial pre-cuts lines 14, 16, 18 may be varied and may be planar or curved to define regular or irregular portions 12 accordingly.

(17) To form a wound packing material similar to the above the following general process may be used. The present process describes a process for converting a single cuboid block of foam into 6 cuboidal wound packing material bodies. The block is initially approximately 200 mm by 100 mm by 180 mm and is cut into 6 blocks of 200 mm by 100 mm by 30 mm. It will be apparent that variations of this method could be used to manufacture wound packing materials of a great variety of different shapes and sizes, and having varying portion size and shapes. A body of porous material is provided which has the dimensions set out above. A first set of parallel planar partial pre-cuts is made in the body using an array of blades 30. The pre-cuts are made perpendicular to, and into, a first face of the body The array (FIG. 6) comprises a number of planes 31 made up of a series of 18 mm wide flat blades 32, and a 9 mm blade 33 at each end of the plane; a gap of 2 mm is provided between each blade in the series. A gap of 10 mm is left between each plane of blades. The array also comprises 5 continuous 100 mm long planar blades 36 which acts to cut the initial block completely into 6 smaller blocks. The first set of partial pre-cuts is achieved by placing the block of foam against the array of blades 30 and urging the blades into and through the block. The pressure required may be generated by a hydraulic press (also known as a clicker press). This is a conventional form of die cutting and the necessary apparatus and techniques are well known to one skilled in the art. Second and third sets of partial pre-cuts are made using a second array 40 of blades (see FIG. 7). In the second array a plurality of cruciform blades 42 are provided. Due to the shape and arrangement of the blades 42, the array is suitable to make two sets of parallel planar partial pre-cuts in two orientations, which are perpendicular to each other. Thus, in one cutting action, two sets of parallel planar partial pre-cuts are made. Each cruciform blade 42 comprises two 18 mm long linear blade elements 44,46 intercepting at each of their midpoints at a right angle to define the cruciform blade. The cruciform blades are arranged in the array to form a square matrix with gaps of 2 mm provided between each cruciform blade. As with the first cut, the second cut is made by applying pressure to drive the blades 42 through the body. The length of the blades in the first and second array are sufficient to pass completely through the body and emerge at the other side.

(18) This process forms 6 cuboids of foam measuring 200 mm100 mm30 mm, which are each formed of cuboids measuring approximately 20 mm20 mm10 mm, each of the cuboid portions being interconnected with adjacent portions by frangible regions of approximately 2 mm thickness.

(19) It should be noted that where a generally cubic body of foam is being prepared the order of the cuts is not particularly significant as the cube is equally structurally stable in all 3 dimensions. However, when preparing a body with a relatively thin minor dimension, as set out in the method above, it is important that the first cut made is the one perpendicular to the plane of the thin dimension (i.e. the smallest face of the cuboid), or that the shape of the block is supported as the cut is made. If the order is reversed, or the block shape is not supported, there is generally an unacceptable amount of crushing and/or corrugation of the body resulting in a significant distortion to the desired cut geometry.

(20) The result of this process is a wound packing material which can be custom shaped by manually removing cuboid portions by tearing the frangible regions interconnecting the portions making up the body. This allows a medical practitioner to shape the body of wound packing material to fit the wound to be packed or dressed. Once the wound packing material has been shaped appropriately, the wound can be dressed for NPWT.