Simulated Body Tissue
The present invention relates to a simulated body tissue, a method of making a simulated body tissue and to the use of a simulated body tissue for teaching and/or practising and/or demonstrating wound closure techniques.
In the medical field, it is necessary for students, doctors and surgeons to be able to practise surgical and clinical techniques. There is a need to practise a variety of wound closure techniques such as gluing techniques, simple interrupted suturing, subcutaneous suturing and stapling. As an alternative to providing an actual body or part of a body for practising such techniques there is a need for an artificial means whereby they can be practised. Known structures providing simulations of body tissue suffer from the disadvantage that they are not sufficiently analogous, either visually or physically, to actual body tissue. In addition, many known structures are not suitable for use with gluing techniques.
According to a first aspect of the present invention there is provided the use of a polymer foam pad as a simulation of body tissue for teaching and/or practising and/or demonstrating wound closure techniques, wherein the polymer is a polar polymer and has a density in the range of 50 - 250 kgs/m3.
Polar polymers attract moisture from the atmosphere which simulates the residual moisture within the skin.
Preferably, the foam pad is polymer of vinyl chloride and more preferably it is a homopolymer of vinyl chloride (PVC). PVC foam has been shown to provide a surprisingly accurate simulation of actual body tissue and is particularly suitable for use in practising wound closure techniques. Additionally, it has the benefit of being a relatively low cost material and as such this makes it ideal for use as a teaching aid. The range of densities have been selected to simulate the differences encountered in actual body tissue. The preferred density is in the range of 190 - 230 kgs/m3 and more preferably the density is approximately
210 kgs/m3 One particularly preferred PVC foam is the AS 810 PVC Foam as supplied by A.G.C. Gasket Company. Another suitable foam is the higher density AS 820 PVC Foam
also supplied by A.G.C. Gasket Company. The foam pad may be used on its own as a training aid or it may be incorporated into another piece of apparatus. For example, the pad may be used as a replaceable abdomen that is inserted into a plastic torso to further increase the realism of the simulation.
When plastics materials are made into foams a gas production compound called a blowing agent is used. It is preferred that the blowing agent used during the manufacturing process is an alkaline blowing agent. It is particularly preferred that the blowing agent is carbonamide. When the blowing agent is alkaline this results in the foam retaining an alkaline residue which has been found to be beneficial when the wound closure technique comprises gluing with a topical skin adhesive.
The foam pad may additionally include a reinforcement of mesh material. This reinforcement preferably comprises nylon, chiffon or lycra.
In order to improve the simulation of the body tissue it is further preferred that the foam pad is coated with a mixture of water based paint and water. The mixture is preferably in the ratio of 1 part paint to 3 parts water and is applied as a thin coating onto the foam. The paint is preferably selected from a range of paints corresponding to a variety of human skin colours. This improves the visual similarity of the foam pad to actual body tissue and therefore provides a more accurate simulation. A particularly preferred range of paints is that produced by Johnstone's Paints. Some of the preferred colours include pink, peach blush, beige, yellow, light tan and dark tan.
The foam pad may be used as simulation of body tissue for the purposes of teaching and/or practising and/or demonstrating a number of different wound closure techniques. For example, the pad can be used to practise gluing techniques with a variety of topical skin adhesives. It is becoming increasingly common for topical skin adhesives to be used to repair low tension lacerations and to close wounds and surgical incisions. Topical skin adhesives offer a number of advantages when compared with traditional wound closure techniques.
They are more convenient and comfortable for the patient because they do not require anaesthetic, are gentler to the skin than sutures or staples, and do not require suture removal.
Topical skin adhesives benefit physicians because application is an easily and quickly learned skill and application time is much quicker than wound closure with sutures. However, it is still necessary to practise these techniques and many known structures providing simulation of body tissue do not provide satisfactory results when used with topical adhesives. It is preferred that the adhesives used are cyanoacrylate based adhesives. More particularly, some of the preferred adhesives include: DERMABO D®, HISTOACRYL®, INDERMIL® and LIQUIBAND®. The simulated body tissue according to the present invention has been shown to react much better to these topical skin adhesives than other known simulations. For example, tests carried out have shown that the present invention has an improved reaction to topical skin adhesives as compared to simulations made from neoprene or polyurethane.
Furthermore, the present invention has been shown to be far superior in its reaction to topical skin adhesives than simulations made of latex.
When the topical skin adhesive is applied to a polymer foam pad according to the present invention it reacts with the residual moisture on the surface of the foam and polymerises forming a strong, waterproof bond.
In one particularly preferred embodiment the foam pad has an alkaline residue and the adhesive used is a cyanoacrylate based adhesive. When this is the case the alkaline residue neutralises the stabiliser in the adhesive and speeds up the curing process. This is another unexpected advantage which the present invention has over prior simulations of body tissue.
Alternatively, the pad may also be used as a simulation of body tissue for the purposes of teaching and/or practising and/or demonstrating interrupted suturing, subcutaneous suturing or stapling techniques.
According to a second aspect of the present invention there is provided simulated body tissue for use in teaching and/or practising and/or demonstrating wound closure techniques, comprising a foam layer which is a simulated fat layer and a layer of a mixture of water based paint and water which is a simulated epidermis, wherein the foam is a polar polymer and has a density in the range of 50 - 250 kgs/m3.
According to a third aspect of the present invention there is provided a method of making simulated body tissue for use in teaching and/or practising and/or demonstrating wound closure techniques, comprising the steps of:
a) providing a first layer of a polar polymer foam having a density in the range of 50
250 kgs/m3; and
b) coating the foam with a layer of a mixture of a water based paint and water.
For a better understanding of the present invention reference will now be made to the accompanying drawings showing, solely by way of example, an embodiment of the present invention and in which:
Fig. 1 is a perspective view of a wound closure teaching pad; and
Fig. 2 is a perspective view of a wound closure teaching pad having a simulated wound.
Referring now to Fig. 1 this shows a wound closure teaching pad 1 in the form of a rectangular PVC foam pad 2. The foam pad 2 has a thickness of 10 mm but may be of a variety of thicknesses to simulate different situations and different parts of the body. The foam pad 2 has a density of 210kgs/m3 in order to simulate a fat layer and is coated with a thin layer 3 of a mixture of a skin coloured water based paint and water to simulate the epidermis. The paint to water is in the ration of 1 :3. The paint may be of a variety of colours to provide accurate simulation of a variety of flesh tones. The paint/water layer 3 is stippled, painted or applied with a roller to the foam pad 2 as thinly as possible in order that the adhesive can penetrate the paint/water layer 3 and adhere to the foam pad 2.
Fig. 2 shows a wound closure teaching pad 4 having a simulated wound 5. The foam pad 2 has the same properties as the foam pad 2 of Fig. 1 and the simulated wound 5 has been created by making an incision in the foam pad 2. The simulated wound 5 has opposing edges
6, 7. Wound closure techniques, such as gluing, can be practised without the need for actual bodies or parts of bodies.