GB2535612A

GB2535612A - Medical device

Info

Publication number: GB2535612A
Application number: GB1522383.7A
Authority: GB
Inventors: Cooney Tim
Original assignee: ORTHOTIC COMPOSITES Ltd
Current assignee: ORTHOTIC COMPOSITES Ltd
Priority date: 2015-12-18
Filing date: 2015-12-18
Publication date: 2016-08-24
Anticipated expiration: 2035-12-18
Also published as: GB2535612B; EP3389973A1; GB201522383D0; WO2017103621A1

Abstract

A method of making a medical device, the method comprising: heating the polymeric material using a halogen, convection or infrared oven; contacting a portion of a tool 2 corresponding to a subjects body part with a layer of polymeric material, preferably propylene, 20 configured to retain the shape of the tool in the absence of a vacuum, a seal 21 is created by joining the polymeric material to itself; contacting at least a portion of the layer of polymeric material with a UV or heat curable material and curing the curable material so that it become rigid to thereby create a medical device. The curable material is a composite sheet including an inner core of fibre substrate impregnated with a polymer resin where the fibres 22 are carbon, aramid and/or glass fibres. The curable material is wrapped in a releasable membrane, polytetrafluoroethylene, and a vacuum permeable breather fabric is placed over the releasable membrane and then placed in a heat tolerant vacuum bag comprising a vacuum valve. The vacuum bag enclosed tool is placed in an oven or autoclave.

Description

Medical Device The present invention relates to medical devices, in particular orthotic or prosthetic devices. More specifically, the present invention relates to a method of making an orthotic or prosthetic composite, and an apparatus for carrying this method.

Plaster of Paris is widely used in orthotic and prosthetic manufacturing to both capture the shape of a person's anatomy, and to modify a workable and unique 'tool' (or positive mould) for use in creating the resultant orthosis or prosthesis. Technicians first create a 'tool' which is a positive shape that reflects an accurate three dimensional configuration of the person's body part to result in robust orthesis/prosthesis manufacture. The advantage of using Plaster of Paris when creating the 'tool' is that it is safe, adaptable and cheap. Also, Plaster of Paris is a suitable material to use when vacuum-forming composites and plastics, or bending metals, during the subsequent manufacture of the orthotic/prosthetic device. However, a problem with using plaster for making the 'tool' is that it is less effective for use as a 'tool' in the curing of co-called "pre-preg" composite materials, i.e. fibre composite sheets pre-impregnated with resin. This is primarily due to the water content in the plaster and, as a result, the plaster has to be protected before the composite material can be overlaid, and ultimately cured. This also applies to polyurethane tools which have been milled in a computer aided milling machine. These tools could also be described as safe, adaptable and cheap. They have a low moisture content (as opposed to plaster), however, the polyurethane tools also need to be prepared in the same way to make them 'releasable' when pre-pregs are applied.

A known method of manufacturing an orthotic or prosthetic using composite material is known as "infusion composite" manufacturing. The method comprises wetting a thin polyvinyl acetate (PVA) bag, and then pulling it over the positive Plaster of Paris 'tool'. The bag shrinks on drying thereby surrounding the plaster, forming a seal and providing a new surface to work on. The tightly fitting PVA bag is tightened further over the 'tool' using active vacuum suction. While the PVA bag is maintained under vacuum, dry carbon fibres are then placed over the outer surface created by the bag covering the plaster 'tool'. Another PVA bag is then placed over the carbon fibres, and resin is flooded under vacuum to infuse with the fibres. The system is then cured by heating in an oven. The curing in this instance is achieved by a chemical catalyst. Ovens are only used in pre-preg manufacturing. Infusion manufacturing relies on chemical catalysts to form the orthotic/prosthetic device. A draw-back of this method is that it is not possible to accurately control the resin content of the product. Additionally, the PVA bags have to remain under vacuum for the entire time that the technician over lays the fibres on the 'tool', and the resin is flooded into the structure. Also, the PVA bags are fragile and can often break during the process, and so the technician must start again.

An alternative prior art method of manufacturing an orthotic or prosthetic composite comprises using pre-impregnated (i.e. "pre-preg") composite fibres, i.e. composite fibres which are already impregnated with a resin. As with infusion composite /0 manufacturing, the method involves first placing a wetted PVA bag over the surface of a positive plaster cast or 'tool'. The bag is allowed to dry and then tightened further using active vacuum suction. Pre-preg fibres are then placed on the bag-covered tool, and another bag is then placed over the fibres and put under vacuum. Heat is then used to cure the resin which is already present in the system. This process allows control of the resin content of the product. However, a problem with this method is that it does not overcome the problems of the PVA bag being fragile and having to remain under vacuum for the entire time that the technician overlays the fibres on to tool, and prepares the tool for the oven cure step. Additionally, the PVA bag is usually destroyed during the heat curing step. This means that the entire process must be repeated if a further curing step is required.

The inventors have developed a novel method for preparing medical devices, such as orthotic and prosthetic devices.

Hence, in accordance with a first aspect, there is provided a method of making a medical device, the method comprising:- -contacting a portion of a tool corresponding to a subject's body part with a layer of polymeric material configured to retain the shape of the tool in the absence of a vacuum; contacting at least a portion of the layer of polymeric material with a curable material; and curing the curable material so that it becomes rigid to thereby create a medical device.

Advantageously, the method of the first aspect does not require the use of PVA bags, because the polymeric material retains the shape of the tool in the absence of a vacuum. -3 -

Advantageously, the curing step does not damage the layer of polymeric material, and so the tool can be used in multiple cure cycles without adjustment to the tool or the protective polymeric layer being necessary.

Preferably, the tool corresponding to a subject's body comprises a unique tool manufactured for a subject. Preferably, the method comprises a step of manufacturing the tool in a process generally known as "rectification".

In one embodiment, the tool is manufactured as follows. A plaster bandage is preferably used to produce a negative plaster mould of the intended subject's body part or limb. Preferably, the negative plaster mould is then filled with liquid plaster whilst a vacuum tube (which is preferably, a metal tube) is placed in the space as it is filled. Preferably, the liquid plaster is allowed to dry, and the original plaster bandage is removed, thereby creating a positive mould, which is an accurate representation of the subject's body part or limb. A technician preferably applies and removes plaster from the positive mould. The aim of the plaster 'rectification' is to obtain a suitable shape for the medical device, which is preferably a prosthesis or orthosis. A technician should be mindful of bony prominences, and areas of the body that are sensitive to pressure. Accordingly, material is preferably added in these areas to alleviate pressure in the final medical device that is made. Conversely, material is preferably removed from areas of the body that are more tolerant to pressure in order to obtain an intimate fit.

In another embodiment, a polyurethane milled tool is manufactured for use in the method of the first aspect. In this embodiment, instead of plaster, a digital scan of the or subject's body part or limb is taken with scanning equipment. The shape is 'rectified' using software with the same philosophy as in plaster rectification.

Advantageously, the unique tool manufactured by either embodiment of the method ensures that the medical device is specifically tailored to the individual.

The medical device may be used externally or internally of the subject. For example, the medical device may be used on, or for a subject's limb, for example the arm, leg or foot. Preferably, the device is an orthosis or a prosthesis.

Preferably, the layer of polymeric material comprises a layer with a thickness between 0.1 mm and 10 mm, more preferably between 0.3 mm and 8 mm, even more preferably -4 -between 0.5 mm and 6 mm, and more preferably between 0.7 mm and 4 mm. Most preferably, the layer of polypropylene comprises a layer with a thickness between 0.8 mm and 3 mm, more preferably between o.9 mm and 2.5 mm, and most preferably between r mm and 2 MM.

The polymeric material is preferably thermoformable. Hence, the polymeric material may be heated to a temperature at which it becomes malleable, and allows drape vacuum forming. Preferably, the polymeric material is resistant to adhesion to epoxy based adhesives. Hence, it is capable of being released from epoxy 'pre-preg' resin /0 systems, as described below.

The polymeric material may comprise nylon, polyethylene, polytetrafluoroethylene or polypropylene. The polymeric material may comprise a homopolymer material, random copolymer material or block copolymer material. Preferably, the polymeric material comprises polypropylene. Hence, the layer of polypropylene may comprise homopolymer polypropylene, random copolymer polypropylene or block copolymer polypropylene. in a preferred embodiment the layer of polypropylene comprises homopolymer polypropylene. One preferred polymeric material that may be used in accordance with the invention is that which is known as 2mm homopolymer, which may be obtained from www.directplastics.co.uk. Preferably, the polymeric material does not comprise polyvinyl acetate (PVA).

Preferably, the method comprises heating the polymeric material before the step of contacting a portion of the tool with the material. Preferably, the method comprises heating the polymeric material to a temperature of at least 150°C, more preferably at least 175°C, and most preferably at least 190°C. Preferably, the method comprises heating the polymeric material for at least zo minutes, more preferably at least 25 minutes, and most preferably at least 3o minutes. The polymeric material may be heated in a halogen oven, a convection oven or an infrared oven. Preferably, the polymeric material is heated in an infrared oven.

Preferably, the step of contacting a portion of the tool with the layer of polymeric material is conducted immediately after the step of heating the polymeric material. Preferably, the heated polymeric material is draped over the tool. Preferably, a seal is created byjoining the polymeric material with itself. The seal is created by joining the partially molten polymeric material around the tool with light pressure. For example, -5 -the technician will be wearing gloves in his hands, which may be used to apply the pressure required to create the seal. A seal is also preferably created around the vacuum tube. The vacuum tube serves two functions. Firstly, it is hollow and provides the source of the vacuum, as discussed below. Secondly, it provides a means by which the tool can be held or gripped during the method, for example by the technician's hand or in a vice.

Preferably, any excess polymeric material is cut away for practical reasons, as it is only waste. Preferably, the excess is cut away after the seal has been created, and before the io polymeric material has cooled and hardened. Once a seal has been obtained, then the vacuum pressure is sufficient to form it.

Preferably, subsequent to creating a seal, the method comprises applying a vacuum to the polymeric material, and thereby causing the polymeric material to fit closely around the tool. The plaster or polyurethane tool has a hollow tube inserted into it. This allows ease of handling, and also allows the tube to be connected to a vacuum system. For example, the tube may be connected to a rotary vane vacuum pump. However, the source of the vacuum could be a domestic vacuum cleaner. One hole in the tube is sufficient to create sufficient vacuum pressure to seal the polymeric material. However, on larger tools, it may be preferred to drill into the internal tube in suitable sections of the tube or tool in order to spread the vacuum pressure sufficiently.

Preferably, the vacuum is maintained until the polymeric material has cooled. The polymeric material may have cooled when it has reached ambient temperature, i.e. -0or about 21°C. The length of time for allowing cooling is usually dependent upon ambient room temperature. For example, if the polymeric material is maintained at about 21 °C, it can take about 45 minutes to cool sufficiently. It is important not to rush this cooling process for fear of weakening the polymeric material, such that it could crack.

The method preferably comprises removing the vacuum, preferably before the curing step. Advantageously, the tool is then no longer connected to a vacuum and may therefore be moved around freely and the polymeric material retains the shape of the tool. For example, the tool may be moved to an area where the curable material is contacted with the layer of polymeric material. -6 -

The curable material may be either a UV-curable or a heat-curable material. Preferably, the curable material is in sheet form. In some embodiments, the material may be tensioned after it has been applied to the polymeric material. in other embodiments, tensioning is not required. Preferably, the curable material is a composite sheet including an inner core of fibre substrate impregnated with a polymer resin. The composite sheet may be of the type often referred to as a "pre-preg", in that it comprises a fibre composite sheet pre-impregnated with resin. Carbon, aramid, dyneema and/or glass fibres are preferred. Each of these fibres may be impregnated with a similar resin system, such as an epoxy based system.

The curable material (i.e. resin) is preferably uncured at the time of manipulation. Advantageously, this allows the curable material to be carefully worked around the 3D shape of the tool. Preferably, the fibres are contacted with the polymeric material covering the tool surface. The fibres are usually woven like a fabric, and so manipulation of the fibre weave over and around polymeric material on the tool may be required. Thus, the fibres are preferably manipulated, such that they form a three dimensional shape represented by the tool. Due to the tacky uncured resin, the prepreg holds its position well on the tool surface. The desired thickness is obtained by adding multiple layers of pre-preg to a pre-determined 'fibre lay-up design'. One preferred curable material that may be used in accordance with the invention is a carbon fibre epoxy resin system pre-preg, which may be obtained from Gurit, Cytex or PRF Composites in which the resin is curable at about 120 C. The step of curing the fibres may comprise either UV-curing or heat-curing the curable material. The pre-preg is preferably wrapped in a releasable membrane. The membrane may be a polytetrafluoroethylene-based film. A vacuum-permeable breather fabric may be placed over the releasable membrane. This resultant structure may then be placed in a heat-tolerant vacuum bag comprising a vacuum valve. The vacuum bag-enclosed tool may be placed in an oven (e.g. convection oven) or an autoclave. The oven or autoclave has a vacuum tube entering into it through an aperture in one side thereof. The tool is preferably placed under vacuum pressure whilst in the oven or autoclave. The vacuum pressurises the pre-preg thereby sucking out any air trappped within the substrate consisting of the tool and curable material. Any resultant air bubbles would only act to weaken the structure. The tool may then be heated for at least 1 or 2 hours at 120 " C. -7 -The method may comprise repeating the steps of laying the curable material on at least a portion of the layer of polymeric material and curing the material. Preferably, the resultant medical device is ultimately removed demoulded' from the tool by prying it therefrom.

Advantageously, it is possible to cure a layer of carbon fibres to produce a partially formed orthosis or prosthesis. Additional carbon fibres can then be laid on to the partially formed orthosis or prosthesis and cured to define external components. Alternatively, or additionally, the method can be used to produce a partially formed orthosis or prosthesis which is then fitted to the individual. This enables any minor changes to be made to the design, such as the shape or stiffness, before many hours are spent forming the completed orthosis or prosthesis.

It is possible to manipulate the shape of the tool in small areas, such as flaring out the shape if there is a fitting problem when donned by the user. The composite material used in the invention is not heat-remouldable, and so it is not possible to heat it and reform it as is possible with polymeric material. However, if shape adjustment of the medical device is required, it is possible to remove the incorrect section of the material by cutting it away. The tool may then be re-shaped in the localised area by using high temperature wax, putty or plaster. Once this has been done, pre-preg may be applied to the area and cured using the processes described above, thereby achieving a re-shaped medical device.

The inventors have also developed an apparatus for forming a medical device using the -0or method of the first aspect.

In a second aspect, there is provided an apparatus for forming a medical device, the apparatus comprising:- -means for contacting a portion of a tool corresponding to a subject's body part with a layer of polymeric material configured to retain the shape of the tool in the absence of a vacuum; means for contacting at least a portion of the layer of polymeric material with a curable material; and means for curing the curable material so that it becomes rigid to thereby create a medical device. -8 -

The apparatus of the second aspect is preferably used for carrying out the method of the first aspect.

All of the features described herein (including any accompanying claims, abstract and 5 drawings), and/or all of the steps of any method or process so disclosed, may be combined with any of the above aspects in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

For a better understanding of the invention, and to show how embodiments of the same io may be carried into effect, reference will now be made, by way of example, to the accompanying Figures, in which:-Figure 1 is a plaster cast of a patient's leg forming a tool that is used for preparing an orthotic device; Figure 2 is the plaster cast of a patient's leg of Figure 1 with a polymeric sheet fitted thereto; and Figure 3 is an orthotic composite made using the method of the present invention.

Examples

Plaster of Paris is safe, adaptable and cheap. Accordingly, Plaster of Paris is used in orthotic and prosthetic manufacturing to both capture the shape of a person's anatomy and modify a workable and unique 'tool' 2 for manufacturing. An example of a tool 2 used to make an orthosis 4 is shown in Figure 1. A unique tool 2 is made for each individual who requires the orthosis or prosthesis.

or For instance, when a tool 2 is needed to manufacture an orthosis, a technician will make the tool 2 using a process generally known as "rectification". In one embodiment, the tool 2 is manufactured as follows. A plaster bandage is used to produce a negative plaster mould of the intended subject's limb. The negative plaster mould is then filled with liquid plaster whilst a hollow metal vacuum tube is placed in the space as it is 3o filled. The liquid plaster is allowed to dry, and the original plaster bandage is removed, thereby creating a positive mould, which is an accurate representation of the subject's body part or limb. The technician applies and removes plaster from the positive mould. The technician must be mindful of bony prominences, and areas of the subject's body that are sensitive to pressure. Accordingly, further material is added in these areas to alleviate pressure in the final medical device that is made. Conversely, material is -9 -removed from areas of the subject's body that are more tolerant to pressure in order to obtain an intimate fit.

In another embodiment, a polyurethane milled tool is manufactured for use in the method of the first aspect. In this embodiment, instead of plaster, a digital scan of the subject's body part or limb is taken with scanning equipment. The shape is 'rectified' using software with the same philosophy as in plaster rectification.

Accordingly, the finished tool 2 comprises a plaster portion 5 corresponding in shape to o a portion of the client's anatomy, for example an arm, leg or foot. In the embodiment illustrated in Figure 1, the tool corresponds to a person's foot 7 and lower leg 9. A metal rod 6 extends out from the plaster portion 5, by which the tool z can be held steady by locating the metal rod 6 in a clamp 8. The rod 6 is hollow and also provides the source of vacuum pressure, as described below.

A i to 2 mm thick layer of homopolymer polypropylene sheet 20 is heated in an infrared oven at i90 °C for 3o minutes. When warm, the polypropylene sheet 20 is then draped over the plaster portion 5 of the tool 2 and a seal 21 is created by joining the polypropylene 20 with itself, as shown in Figure 2. The seal 21 is created by joining the zo sheet zo with itself. The seal 21 is created by joining the partially molten sheet 20 around the tool 2 with light pressure applied from the technician's glove-protected hands. A seal 21 is also created around the rod 6, i.e. "vacuum tube". A vacuum is then applied to the section of the tool 2 comprising the plaster portion 5 covered by the polypropylene sheet 20, and this causes the polypropylene 20 to fit tightly around the plaster 5, as shown in Figure 2.

The plaster or polyurethane tool z has a hollow vacuum tube 6 inserted into it. This allows ease of handling, and also allows the tube 6 to be connected to a vacuum system (not shown). For example, the tube 6 can be connected to a rotary vane vacuum pump or a domestic vacuum cleaner. One hole in the tube 6 is usually sufficient to create sufficient vacuum pressure to seal the polypropylene around the tool 2. However, on larger tools 2, it may be preferred to drill into the internal tube 6 in suitable sections in order to spread the vacuum pressure sufficiently. The vacuum is maintained until the polypropylene has cooled, which is usually at ambient or about 21"C. The length of time for allowing cooling depends upon the ambient room temperature. For example, if the polypropylene is maintained at about 21 "C, it can take about 45 minutes to cool sufficiently.

After the polypropylene 20 has cooled, the vacuum is removed and the polypropylene 5 sheet 20 retains the shape of the tool 2. The polypropylene-covered tool 2 can then be moved freely around the workshop using rod 6, as it is no longer tied to the vacuum system.

As shown in Figure 2, pre-impregnated (pre-preg) carbon fibres 22 are then placed on the polypropylene-covered tool 2 in the desired locations for making the orthosis. Accordingly, to make the orthosis 4 shown in Figure 3, the pre-preg carbon fibres 22 are placed on the sole to of the foot 7, on a portion 12 of either side of the foot, along the back 14 of the leg 9 and extending around a portion of the calf 16.

Carbon, aramid, dyneema and/or glass fibres 22 are preferred. Each of these fibres 22 may be impregnated with a similar resin system, such as an epoxy based system. The resin is uncured at the time of manipulation, and so the fibres 22 are contacted with the tool surface. The fibres 22 are usually woven like a fabric, and so manipulation of the fibre weave over and around polymeric material on the tool may be required. Thus, the fibres 22 are manipulated such that they form a three dimensional shape represented by the tool. Due to the tacky uncured resin, the pre-preg holds the position well on the tool surface. The desired thickness is obtained by adding multiple layers of pre-preg to a pre-determined 'fibre lay-up design'. One preferred curable material that may be used is a carbon fibre epoxy resin system pre-preg, which may be obtained from Gurit, Cytex or PRF Composites in which the resin is curable at about 120 °C.

The carbon fibres 22 are then cured. The step of curing the fibres can involve either UV-cu ring or heat-curing the curable material. The pre-preg is wrapped in a releasable membrane, such as a polytetrafluoroethylene-based film. A vacuum-permeable breather fabric is then placed over the releasable membrane, and this resultant structure is then placed in a heat-tolerant vacuum bag comprising a vacuum valve. The vacuum bag-enclosed tool is then placed in a convection oven (or an autoclave). The oven or autoclave has a vacuum tube entering into it through an aperture in one side thereof. The tool 2 is placed under vacuum pressure whilst in the oven or autoclave.

The vacuum pressurises the pre-preg thereby sucking out any air trappped within the substrate. Any resultant air bubbles would only act to weaken the structure. The tool 2 may then be heated for at least 1 or 2 hours at 120"C.

The curing process does not damage the protective polypropylene layer 20 which is 5 placed over the tool 2. Accordingly, the tool 2 can be used in multiple cure cycles without any adjustment to the tool 2 or the protective polypropylene layer 20 being necessary.

The resultant orthosis is removed 'clemoulded' from the tool 2 by mechanically prying it to off the tool 2. The polypropylene sheet 20 does not stick to the resin, and so this process is straightforward unless there is some sort of geometry that 'locks' the device in place. The orthoses usually requires their edges to be smoothed. Then, straps and padding etc.,as necessary, can be added as indicated by the design.

Preparing a prosthesis is essentially the same as making an orthosis. Though a prosthesis often has a geometry that 'locks' the device onto the tool. if this happens, the tool 2 can be destroyed to remove device. Alternatively, the device can be cured with seams' that separate during the demoulding process. These seams can be strengthened with adhesion techniques whilst the prosthesis is removed from the tool 2.

Summary

The ability to use multiple cure cycles without the need for any tool maintenance makes the manufacture of an orthosis 4 or prosthesis more adaptable. Accordingly, it is possible to cure a pre-prep layer to produce a partially formed orthosis or prosthesis. A technician can then accurately add additional pre-preg material 22 to the partially formed orthosis or prosthesis to define external components once the additional prepreg material is cured. Alternatively, or additionally, the method can be used to produce a partially formed orthosis or prosthesis which is then fitted to a client. This enables any minor changes to be made to the design, such as the shape or stiffness, before many hours are spent forming the completed orthosis or prosthesisThis polishing process takes time, and so time is saved by 'fitting' the device before it is finished to ensure no wasted effort.

It is possible to manipulate the shape of the tool in small areas -such as flaring out the 35 shape if there is a fitting problem when donned on the user. Additionally, since the tool will still be available after the orthosis or prosthesis is finished it can be used to repair -12 -the orthosis or prosthesis when necessary. This is more cost-effective than using a prior art method because the to& will not need further maintenance before it can be used.

Claims

-13 -Claims 1. A method of making a medical device, the method comprising:-contacting a portion of a tool corresponding to a subject's body part with a layer of polymeric material configured to retain the shape of the tool in the absence of a vacuum; contacting at least a portion of the layer of polymeric material with a curable material; and curing the curable material so that it becomes rigid to thereby create a medical device.
2. A method according to claim 1, wherein the medical device is used externally or internally of the subject.
3. A method according to either claim 1 or claim 2, wherein the medical device is an orthosis or a prosthesis.
4. A method according to any preceding claim, wherein the layer of polymeric material comprises a layer with a thickness of between 0.1mm and 10 mm, or between 20 0.3 mm and 8 mm, or between 0.5 mm and 6 mm, or between 0.7 mm and 4 mm.
5. A method according to any preceding claim, wherein the polymeric material is thermoformable.
6. A method according to any preceding claim, wherein the polymeric material comprises nylon, polyethylene, polytetrafluoroethylene or polypropylene.
7. A method according to any preceding claim, wherein the polymeric material comprises a homopolymer material, random copolymer material or block copolymer 30 material.
8. A method according to any preceding claim, wherein the polymeric material comprises polypropylene.

-14 -
9. A method according to any preceding claim, wherein the method comprises heating the polymeric material before the step of contacting a portion of the tool with the material.
10. A method according to any preceding claim, wherein the method comprises heating the polymeric material to a temperature of at least 150"C, or at least 175°C, or at least 190°C.
11. A method according to any preceding claim, wherein the method comprises /0 heating the polymeric material for at least 20 minutes, or at least 25 minutes, or at least 3o minutes.
12. A method according to any preceding claim, wherein the polymeric material is heated in a halogen oven, a convection oven or an infrared oven.
13. A method according to any preceding claim, wherein heated polymeric material is draped over the tool.
14. A method according to any preceding claim, wherein a seal is created by joining the polymeric material with itself.
15. A method according to any preceding claim, wherein the method comprises applying a vacuum to the polymeric material, and thereby causing the polymeric material to fit closely around the tool. -0or
16. A method according to claim 15, wherein the vacuum is maintained until the polymeric material has cooled.
17. A method according to any preceding claim, wherein the curable material is either a UV-curable or a heat-curable material.
18. A method according to any preceding claim, wherein the curable material is a composite sheet including an inner core of fibre substrate impregnated with a polymer resin.

-15 -
19. A method according to claim 18, wherein the composite sheet is of the type often referred to as a "pre-preg", in that it comprises a fibre composite sheet pre-impregnated with resin.
20. A method according to either claim 18 or 19, wherein the fibres are carbon, aramid, dyneema and/or glass fibres.
21. A method according to any one of claims 18-20, wherein the fibres are contacted with the polymeric sheet on the tool.
22. A method according to any one of claims 18-21, wherein the fibres are manipulated such that they form a three dimensional shape represented by the tool.
23. A method according to any one of claims 18-22, wherein the pre-preg is wrapped in a releasable membrane, optionally polytetrafluoroethylene-based film.
24. A method according to claim 23, wherein a vacuum-permeable breather fabric is placed over the releasable membrane.
25. A method according to claim 24, wherein this resultant structure is placed in a heat-tolerant vacuum bag comprising a vacuum valve.
26. A method according to any one of claims 18-22, wherein the vacuum bag-enclosed tool is placed in an oven or an autoclave. -0or
27. A method according to any one of claims 18-22, wherein the tool is placed under vacuum pressure whilst in the oven or autoclave thereby sucking out any trappped air.
28. A method according to any preceding claim, wherein the resultant medical device is removed demoulded' from the tool by prying it therefrom.
29. An apparatus for forming a medical device, the apparatus comprising:-means for contacting a portion of a tool corresponding to a subject's body part with a layer of polymeric material configured to retain the shape of the tool in the absence of a vacuum; -16 -means for contacting at least a portion of the layer of polymeric material with a curable material; and means for curing the curable material so that it becomes rigid to thereby create a medical device.
30. An apparatus according to claim 29, wherein the apparatus is for performing the method according to any one of claims 1-28.Amendments to the claims have been filed as follows: Claims 1. A method of making a medical device, the method comprising:- - draping a layer of a thermoformable polymeric material over a portion of a tool corresponding to a subject's body part such that the polymeric material retains the shape of the tool in the absence of a vacuum; - contacting at least a portion of the layer of polymeric material with a curable material; and - curing the curable material so that it becomes rigid to thereby create a medical device.2. A method according to claim 1, wherein the medical device is configured for use externally or internally of the subject.3. A method according to either claim 1 or claim 2, wherein the medical device is an CO orthosis or a prosthesis.O O4. A method according to any preceding claim, wherein the layer of polymeric material comprises a layer with a thickness of between 0.1 mm and 1c) mm, or between o.3 mm and 8 mm, or between 0.5 mm and 6 mm, or between 0.7 mm and 4 mm.5. A method according to any preceding claim, wherein the polymeric material comprises nylon, polyethylene, polytetrafluoroethylene or polypropylene.6. A method according to any preceding claim, wherein the polymeric material comprises a homopolymer material, random copolymer material or block copolymer material.7. A method according to any preceding claim, wherein the polymeric material comprises polypropylene.8. A method according to any preceding claim, wherein the method comprises heating the polymeric material before the step of contacting a portion of the tool with the material.9. A method according to any preceding claim, wherein the method comprises heating the polymeric material to a temperature of at least 150"C, or at least 175"C, or at least 190"C.10. A method according to any preceding claim, wherein the method comprises heating the polymeric material for at least 20 minutes, or at least 25 minutes, or at least 3o minutes.11. A method according to either claim 9 or claim 10, wherein the polymeric material is heated in a halogen oven, a convection oven or an infrared oven.CO 12. A method according to any one of claims 9 to 11, wherein the polymeric material is O heated prior to being draped over the tool.O13. A method according to any preceding claim, wherein a seal is created by joining the polymeric material with itself.14. A method according to any preceding claim, wherein the method comprises applying a vacuum to the polymeric material, and thereby causing the polymeric material to fit closely around the tool.15. A method according to claim 14, wherein the method comprises heating the polymeric material and then allowing the polymeric material to cool, wherein the vacuum is maintained until the polymeric material has cooled.16. A method according to any preceding claim, wherein the curable material is either a UV-curable or a heat-curable material.17. A method according to any preceding claim, wherein the curable material is a composite sheet including an inner core of fibre substrate impregnated with a polymer resin.18. A method according to claim 17, wherein the composite sheet is of the type often referred to as a "pre-prep", in that it comprises a fibre composite sheet pre-impregnated with resin.19. A method according to either claim 17 or 18, wherein the fibres are carbon, aramid, dyneema and/or glass fibres.20. A method according to any one of claims 17-19, wherein the fibres are contacted with (.0 the polymeric sheet on the tool.O O21. A method according to any one of claims 17-2o, wherein the fibres are manipulated such that they form a three dimensional shape represented by the tool.22. A method according to any one of claims 17-21, wherein the pre-preg is wrapped in a releasable membrane.23. A method according to claim 22, wherein the releasable membrane is polytetrafluoroethylene-based film.24. A method according to either claim 22 or claim 23, wherein a vacuum-permeable breather fabric is placed over the releasable membrane.25. A method according to claim 24, wherein this resultant structure is placed in a heat-tolerant vacuum bag comprising a vacuum valve.26. A method according to any one of claims 17-21, wherein the vacuum bag-enclosed tool is placed in an oven or an autoclave.27. A method according to any one of claims 17-21, wherein the tool is placed under vacuum pressure whilst in the oven or autoclave thereby sucking out any trapped air.28. A method according to any preceding claim, wherein the resultant medical device is removed demoulded' from the tool by prying it therefrom.29. An apparatus for forming a medical device, the apparatus comprising:- - means for contacting a portion of a tool corresponding to a subject's body part with aO COlayer of polymeric material configured to retain the shape of the tool in the absence of O a vacuum; - means for contacting at least a portion of the layer of polymeric material with a curable material; and - means for curing the curable material so that it becomes rigid to thereby create a medical device.3o. An apparatus according to claim 29, wherein the apparatus is for performing the method according to any one of claims 1-28.