GB2090535A

GB2090535A - Medical inserts

Info

Publication number: GB2090535A
Application number: GB8200218A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-01-06
Filing date: 1982-01-05
Publication date: 1982-07-14
Also published as: GB2090535B

Abstract

A shaped, hydrophilic, water- swellable medical insert for insertion into a body orifice, which substantially retains its shape on swelling in the presence of water, which comprises a granular or fibrous material dispersed in a matrix, and in which the shape includes a head portion 1 of large cross-section, normal to the axis of insertion (A), relative to a body portion 2. The insert may include a medicament. It may be used to support a graft. <IMAGE>

Description

SPECIFICATION Medical inserts This invention relates to bodies which can be used as medical inserts, i.e. as inserts for body orifices such as the auditory meatus.

Ear plugs are known. It is also known to insert a member into the auditory meatus following surgery. A known material for use in such circumstances is natural sponge. Sponge does not expand and, in order to provide a protective cover over, say, a graft, it is necessary to insert an unsatisfactorily large amount of the material into the auditory meatus. This can cause pressure on a graft. Further, a wound may grow into the sponge; this can cause reopening of the wound when the sponge is removed.

Tampons are examples of swellable body inserts. The material of tampons is generally cellular or fibrous throughout. Their shape is generally right cylindrical.

A shaped, hydrophilic, water-swellable material insert according to the present invention, for insertion into a body orifice, comprises a granular or fibrous material dispersed in a matrix; the shape of the body should be substantially retained on swelling in the presence of water; the body shape includes a head portion of relatively large cross-section, normal to the axis of insertion.

Inserts of the invention will now be described by way of example for use in the auditory meatus. In such use, they may be swollen in situ by the introduction of water of an aqueous medication, e.g. comprising antibiotics, or by moisture from a wound in the meatus which it is desired to treat. If it is desired that the material of the insert should grow into a wound in the meatus, it is preferred that the body should be a gel.

Since an insert of the invention maintains its shape on swelling, its use can be controlled to a large extent. It can support a graft, and hold that graft despite coughing. The insert may comprise a medicament and, by suitable choice of materials, this medicament can be allowed to reach a wound or graft in a controlled manner. Example of medicaments which can be used are chlorhexidine acetate, methylparaben, phenylmercuric nitrate, thimerosal and sodium benzoate.

An insert of the invention can be prepared by dehydration of the mixed consistuent materials. Steam pressure may be used in formation although it will often be suitable simply to form the mixture in a suitable mould. The insert may be simply sterilised, e.g. by radiation. It is available for use in a variety of loci including wards, outpatients and theatres.

An insert of the invention is simple to use.

In use, it can expand by up to 30 times its dehydrated size; the degree of swelling can be controlled as desired. The swollen insert can act mechanically to overcome oedema and provide protection, to grafts against coughing and straining constipation, and to the middle ear against infection, by acting as a seal. The insert may comprise suitable components to these ends, including ear drops.

An insert of the invention can be used in assocation with an ear cap. It is particularly suitable for use with the device described in my International Patent Publication No. WO 81/02515.

The fibrous or granular material used in an insert of the invention will generally be at least partially hydrophilic and absorptive. The material may be organic or inorganic, e.g.

hydro-colloidal, and examples are cellulosic materials such as oxidised cellulose, bentonite, colloidal silica, hectorite and laporite.

The matrix used in an insert of the invention will generally also be hydrophilic and absorptive. Suitable materials include polyvinyl alcohol, polyvinyl pyrrolidone, silicones and gelatin, and mixtures of two or more thereof. Gelatin is the most preferred matrix material.

An insert of the invention may consist solely of the granular or fibrous material and matrix material, optionally with a medicament and/ or a disinfectant. Fillers may however also be included, for bulk/stability, which are neither hydrophilic or absorptive. The body will generally comprise at least 50, e.g. 75, % by weight of the granular or fibrous material and any filler, the balance, e.g. 25% by weight, being the matrix material. For use in the auditory meatus, the dehydrated body will usually have a maximum cross-section, i.e.

orthogonal to the axis of insertion, of 6 mm.

Its length, i.e. along the axis of insertion, will generally be at least 10, and usually at least 15, mm, in order that the insert can be easily grasped for removal.

The structure of an insert of the invention will be such that the fibrous or granular material is substantially uniformly distributed in the matrix. Such a structure allows water to be distributed evenly throughout the body, by capillary action; this allows substantially uniform swelling, so that the swollen body retains the shape of the dehydrated body. If the body comprises a fibrous material embedded in a matrix, the fibres may suitably be orientated along the axis of insertion of the body.

In a first embodiment of the invention, a medical insert comprises a body having a generally T-shaped cross-section (in all planes common to the axis of insertion). It is intended that the head of the insert, which may be described as a meato-tympanic ear wick, should come into contact with the tympanic membrane, the "stem" of the body serving as a means to locate the insert in, and remove it from, the ear. The head may have a thickness of about 1 mm and a total width of about 5 mm. The stem may be about 2 mm wide and about 15 mm long, in which case, in use, it will protude from the aditory meatus by, say, 1 to 2 mm.

The T-shaped insert described above may be used for many conditions affecting the external auditory meatus of the human ear.

For example, it may be used to treat traumatic injury to the meatal skin or to the bony cartilaginous skeleton of the meatus, alergic conditions affecting the skin of the meatus, e.g. allergic external otitis with oedema of the skin, all bacterial and viral conditions affecting the meatal skin, e.g. otomycosis, furuncles and herpetic lesions, and otitis externa malignans. Such an insert may also be applied to the human ear following all types of surgery, particularly operations involving repair of defects in the drum head, mastoid surgery of the middle ear, surgery of the inner ear, all forms of tympanoplasty and all kinds of surgery involving the external auditory meatus.

A second embodiment of the invention is broadly similar to the first embodiment described above. However, the T-shape is modified so that one side of the stem, the mastoid side, is convex outwards. In this case, the minimum and maximum thicknesses of the stem may be of the order of 2 and 4 mm, respectively.

This modified T-shape cross-section insert may be described as a meato-mastoid ear wick. It is suitable for all types of tympanoplasty involving mastoid surgery with the drainage point through the external auditory meatus. The "bulge" is designed to fill the surgically created cavity and to support the meato-mastoid skin flap or graft.

A third embodiment of the invention is ovoid in cross-section. In the dehydrated state, such a body, which may be termed an oto-tympanic ear pill, may have a maximum thickness of no more than 2 mm.

A pill-type insert of the type described may be applied to the human ear at the end of any surgical operation to the middle ear or which involves application of a graft or tympanic flap. Such an insert should be applied in order to keep a graft in position, and to support a prosthesis in any type of osiculoplasty, e.g.

incudo-stapedopexy. Such a body can act as a glue, following which an insert, for example of either of the first two types described above, can be inserted, depending on the type of surgery involved.

The invention will now be described by way of example with reference to the accompanying drawings. The three figures respectively show cross-sections of the three embodiments of ear inserts of the invention. The inserts illustrated in Figs. 1 and 2 comprise a head 1 and a stem 2. In all three figures, the intended direction of insertion into the auditory meatus is shown by the arrow at A.

The following Examples illustrate the preparation of inserts of the invention.

Example 1 100 mg chlorhexidine acetate were dissolved in 275 ml distilled water and 500 ml of a 0.08% aqueous mixture of methylparaben and propylparaben (2:1) were added. 50 g polyvinyl alcohol W25/140 were added and dissolved with the aid of heat on a water bath, with continuous stirring. 15 ml triethanolamine were dissolved in 200 ml glycine, and 1 g pectin was added. Following cooling, the glycerine mixture was added to the polyvinyl alcohol/-water mixture, with stirring. Distilled water was added to achieve the desired consistency. The mixture was poured into a ceramic mould tray and allowed to dry, to provide pills as illustrated in Fig. 3.

Example 1 was repeated using Pharmagel instead of pectin, and 1:50000 phenylmercuric nitrate, 1:50000 thimerosal, 1.5% sodium benzoate or a 0.2% methylpareben/-0.02% propylparaben mixture instead of the given paraben mixture. Such pills can be used in post-operative cases where profuse bleeding has occurred.

Example 2 10 g zinc oxide were mixed with 40 g sterilised bentonite and 200 ml glycerine. The mixture was sprinkled onto the surface of hot water, allowed to stand for 24 hours with occasional stirring, and allowed to cool.

10 g polyvinyl alcohol W25/140 were added to 200 ml cold distilled water, and then dissolved over a water bath, with continuous stirring, and allowed to cool. Separately, 2 g zinc oxide, 500 mg dried calcium sulphate, 30 ml glycerine and 0.08% methylparaben were mixed together, and subsequently with a mixture of the cooled polyvinyl alcohol solution and bentonite-containing system.

Cellulose fibres were prepared by dissolving wood pulp or short fibre cotton in caustic soda and carbon disulphide, and forcing the solution through spinnerets into an acid salt bath. The mixture obtained above was spread on a ceramic mould and the fibres were implanted. The mixture was then moulded as desired, e.g. as illustrated in Fig. 1.

Claims

1. A shaped, hydrophilic, water-swellable medical insert, for insertion into a body orifice, which substantially retains its shape on swelling in the presence of water, which comprises a granular or fibrous material dispersed in a matrix, and in which the shape includes a head portion of relatively large cross-section, normal to the axis of insertion.

2. An insert according to claim 1, which includes a medicament.

3. An insert according to claim 1 or claim 2, which has a maximum cross-section, normal to the axis of insertion, of 6 mm.

4. An insert according to any preceding claim, in which the fibrous or granular material is at least partially hydrophilic and absorptive.

5. An insert according to any preceding claim, in which the matrix comprises gelatin.

6. A graft supported on an insert according to any preceding claim.