GB2305289A - Surgical models - Google Patents

Abstract

A surgical model is formed of an admixture of glycerine, gelatine and water treated with a cross-linking agent, e.g., an aldehyde in the form of formalinised water, which is preferably surface heated into the anatomically shaped moulding. One volume of gelatine in one volume of water forms the preferred basic mix, which may be plasticised with from one volume to six volumes of glycerine according to the softness or plasticity required, a higher proportion of glycerine resulting in a softer material. Bubbling agents, fibrous materials, powders, and/or colourants may be added to the mixture to afford realistic simulated anatomical components.

Description

SURGICAL MODELS This invention relates to surgical models and has for its principal object the provision of models on which surgical procedures can be practised or demonstrated, e.g. arthroscopy or keyhole surgery on joints such as the knee, shoulder, elbow, ankle or wrist; also other than on joints, e.g. the abdomen or pelvis; the eye; and also for practising suturing of blood vessels, bowel, or skin and subcutaneous tissue; spinal disc prolapse; micro-disectomy.

In furtherance of the principal object it is a secondary object to provide materials for surgical models that simulate the textures of the natural anatomical components such as bone, cartilage, tendons, ligaments, breast, skin and subcutaneous tissue, or cornea, internal organs. Another secondary object is to provide materials for surgical models that simulate the colours of the natural anatomical components.

A further object is to provide surgical models that are encapsulated so that simulated surgical procedures can be conducted in a wet environment, where either water or saline solution will be instilled under pressure.

According to the principal concept of the present invention, a surgical model is formed of an admixture of glycerine, gelatine and water treated with a cross-linking agent.

The proportions of glycerine, gelatine and water depend upon the nature of the anatomical component to be simulated. One volume of gelatine in one volume of water forms the preferred basic mix, which may be plasticised with from one volume to six volumes of glycerine according to the softness or plasticity to be achieved. Thus, a higher proportion of glycerine will result in a soft material, suitable, for example, for simulating a breast or fat pad, while a higher proportion C . gelatine will result in a harder material, suitable, for example, for simulating a ligament or tendon, but also somewhat dependent on water content.

Flowability of the mixture when moulding will depend largely on the coarseness, or otherwise, of the gelatine and/or the water content. Plasticity may be increased by additives such as glycerol, sorbitol or polyethylene glycol.

The mixture may be formed initially into a stock mass in an initial or "rough" mould, a piece being cut off the stock mass, melted and formed into the required anatomical shape in a final mould.

The anatomically shaped moulding is surface treated with the cross-linking agent, e.g.

an aldehyde in the form of formalinised water, to effect the cross-linking which affords stability of the moulded material, in water or saline solution, in dry heat (say, up to around 50 C, such as may be experienced during transportation), against shrinkage and discolouration, whilst having ability to bond to hot resin, such as may be used to produce a core material, such as simulated cancellous bone. Such cross-linking could also be effected during the moulding process by mixing the aldehyde into the warrn mixture.

Bubbly material may be produced by incorporating in the mixture materials such as baking powder or bicarbonate of soda. Fibrous materials, such as nylon, may be added to provide reinforcement and/or to produce a texture simulating a tendon or ligament. Other additives which may be used are plaster of paris and other powders, e.g. silicones.

Colourants, such as titanium dioxide, acrylic colours and/or artists pigments, may be added to afford realistic colour to the simulated anatomical component or components, being of value in the visual aspects of surgical procedures, particularly in arthroscopy or keyhole surgery.

The anatomically shaped mou:d may be filled in stages with materials having different consistencies, texture and/or colour, to simulate the composite nature of some anatomical components. Thus, in the case of a simulated knee joint the articular surfaces may be cast first and allowed to cool and set, then the rest of the mould is filled with liquid resin, which gives out heat during the reaction of its catalyst, and which heat binds the two materials together.

A simulated anatomical joint in accordance with the invention may be encapsulated in rubber or other impervious elastomeric material, so that the joint can be instilled with water or saline solution and can also be manipulated into attitudes normally adopted for different surgical procedures. The capsule may contain other anatomical components, such as menisci and/or soft tissue folds called plicae.

The capsule may be mounted on a stand or clamp, or it may be incorporated in a model of a limb, for example, a knee or ankle in a model leg.

Claims (20)

1. A surgical model formed of an admixture of glycerine, gelatine and water treated with a cross-linking agent.

2. A surgical model as in Claim 1, wherein one volume of gelatine in one volume of water forms the basic mix, which is plasticised with from one volume to six volumes of glycerine according to the softness or plasticity to be achieved.

3. A surgical model as in Claim 1 or Claim 2, wherein plasticity is increase by additives such as glycerol, sorbitol or polyethylene glycol.

4. A surgical model as in any one of the preceding Claims, wherein the mixture is formed initially into a stock mass in an initial or "rough" mould, a piece being cut off the stock mass, melted and formed into the required anatomical shape in a final mould.

5. A surgical model as in any one or more of the preceding Claims, wherein the anatomically shaped moulding is surface treated with the cross-linking agent or cross-linked during the moulding process.

6. A surgical model as in any one or more of the preceding Claims, wherein the cross-linking agent is an aldehyde in the form of formalinised water.

7. A surgical model as in any one or more of the preceding Claims, wherein bubbly material is produced by incorporating in the mixture materials such as baking powder or bicarbonate of soda.

8. A surgical model as in any one or more of the preceding Claims, wherein fibrous materials may be added.

9. A surgical model as in i ny one or more of the preceding Claims, wherein powders such as plaster of paris or silicones are added to the mixture.

10. A surgical model as in any one or more of the preceding Claims, wherein colourants are added to the mixture to afford realistic colour to the simulated anatomical component or components.

11. A surgical model as in any one or more of the preceding Claims, wherein the anatomically shaped mould is filled in stages with materials having different consistencies, texture and/or colour, to simulate the composite nature of some anatomical components.

12. A simulated knee joint as in Claim 11, wherein the articular surfaces are cast first and allowed to cool and set, then the rest of the mould is filled with liquid resin, which gives out heat during the reaction of its catalyst, and which heat binds the two materials together.

13. A simulated knee joint as in Claim 12, wherein the concentration of the crosslinking agent is adjusted so that the cast articular surfaces exhibit some tackiness which facilitates binding to the hot resin.

14. A simulated anatomical joint as in any one or more of the preceding Claims encapsulated in rubber or other impervious material.

15. A simulated anatomical joint as in Claim 14 instilled with water or saline solution.

16. An encapsulated simulated anatomical joint as in Claim 14 or Claim 15 containing other anatomical components, such as menisci and/or soft tissue folds called plicae.

17. An encapsulated simulated anatomical joint as in any one or more of Claims 14 to 16 mounted on a stand or clamp.

18. An encapsulated simulated anatomical joint as in any one or more of Claims 14 to 16 incorporated in a model of.. limb.

19. An encapsulated simulated knee joint as in any one of Claims 12 to 16 incorporated in a model leg.

20. An encapsulated simulated ankle joint as in any one or more of the preceding Claims incorporated in a model leg.