GB1592543A - Magnetic closure device for an artificial bowel outlet - Google Patents

Abstract

The magnetic closure comprises an annular magnet (3) to be implanted on the artificial intestinal outlet and a plug (4) of a permanently magnetic or low-retentivity material for closure purposes. The plug (4) is exchangeably arranged in a sheath (5) made of an open-cell polyvinylacetal foam whose inner surface is preferably provided with a water-repellent silicon finish. The plug (4) advantageously has an axial central opening (7) and a return thread (8). <IMAGE>

Description

(54) MAGNETIC CLOSURE DEVICE FOR AN ARTIFICIAL BOWEL OUTLET (71) We, TEMCA CHEMISCHE UNION GmbH, a body corporate organised under the laws of the German Federal Republic, of 80, Schoppershofstrasse (Tempo-Hans) D8500, Niirnberg, German Federal Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a magnetic closure device for an artificial bowel outlet.

Magnetic closure devices for artificial bowel outlets have been proposed which comprise a ring magnet to be implanted at the bowel outlet and a plug made of permanent magnetic or soft magnetic material associated therewith. In one particular construction of such a magnetic closure device, an annular permanent magnet which encircles the bowel outlet is implanted just beneath the abdominal wall and the closure part is constructed as a closure plate or closure cap. In another previously proposed construction the cap is improved with an additional permanent magnetic or soft iron part which has an axially magnetisable magnet core projecting into the implanted magnet system, see e.g., Specification No.

1,47 1,158.

The disadvantages of the previously proposed magnetic closure devices are that the cap rests upon the abdominal wall and that the closure part projecting into the ring magnet is not sealed with reference to the bowel outlet.

According to the present invention there is provided a closure device for an artificial bowel outlet with a ring magnet implanted at the bowel outlet wherein the closure device comprises a plug made of permanent magnetic or magnetisable material mounted in an envelope made of open-cell polyvinyl acetal foam.

In an optimum embodiment, the present magnetic closure device for an artificial bowel outlet can be constructed in such a way that it can be inserted flush with the abdominal wall and can provide a hygienically satisfactory seal effective over long periods of time.

The polyvinylacetal foam envelope may be water proofed at its interior surface, preferably with a silicone, thereby to improve the sealing function of the proposed magnetic closure device is improved.

In order to enable the invention to be more readily understood, reference will now be made to the accompanying drawings which illustrate diagrammatically and by way of example some embodiments thereof, and in which: Figure 1 is a schematic longitudinal section through an artificial bowel outlet with a magnetic closure device installed therein, Figure 2 is a schematic longitudinal section through one embodiment of a plug of the closure device, Figure 3 is a schematic longitudinal section through another embodiment of a plug.

Referring now to Figure 1 of the drawings, there is shown the end 1 of an artificial bowel into which a ring magnet 3 is implanted as closely as possible to the bowel outlet 2. The ring magnet may consist of a sintered metal alloy, preferably one with high coercitivity; platinum-cobalt alloys or samarium-cobalt alloys have been found to be suitable materials. It is advantageous if the permanent magnet ring is also coated with a plastics material favourable for implantation, e.g.

based on polyoxymethylene. However, instead of the metal alloys mentioned, oxidic permanent magnet materials, e.g., ferrite of high coercitivity, may also be used.

In the embodiment illustrated in Figure 1, the permanent magnet is radially magnetised, with its north pole lying at the inner annular surface of the ring magnet and the south pole at the outer annular surface of the ring magnet. However, especially where the ring magnet is an oxidic permanent magent, a different poling of the magnet is also possible. e.g., one in which an alternate sequence of north and south poles is arranged at the inner surface either in the longitudinally axial direction or in the peripheral direction. The last-mentioned poling has the advantage that the wall thickness of the implanted magnet ring can be made smaller.

A plug 4, which likewise consists of permanent magnetic or magnetisable material, is associated with the magnet ring 3. As shown in Figure 1, a plug of permanent magnetic material is chosen. at the outer envelope of which an alternate sequence of south and north poles extending in the direction of the longitudinal axis is present.

But here again, a different magnet pole sequence may be chosen. However, the sequence illustrated in the drawing, in conjunction with the ring magnet likewise illustrated, has the effect that the magnet when inserted automatically assumes the required position.

The plug 4 is exchangeably mounted in an envelope 5, which consists of an open-cell polyvinyl acetal foam, this material having proved especially successful because it is easy to work and physiologically harmless.

The envelope 5 is constituted by an at least approximately cylindrical sleeve 6 which is formed with a longitudinally axial central aperture 7, and the envelope 5 has a retrieval thread 8 embedded therein. It has been found particularly successful if the sleeve 6 is thickened at its ends 9 and, 10 as illustrated in Figure 3. When a plug shaped in this manner is inserted into the bowel outlet 2, particularly firm abutment is produced in the region of the two thickened parts, so that ovcrall a kind of labyrinth seal is formed.

In another embodiment, the diameter of the central aperture 7 is smaller than the diameter of the magnet plug 4 to be inserted therein. The magnetic plug can only be inserted into such an envelope when the envelope has been softened up in a manner to be explained hereinbelow. But when the magnetic plug is inserted into such a softened envelope, it sits tightly in the latter and cannot slip or drop out during wear.

In another embodiment, the central aperture 7 is closed at one end 11 as shown in Figure 3. This being the end which points towards the interior of the body during use.

Such a closure device has the advantage that the plug 4 is shielded on all sides from the interior of the bowel and cannot come into contact with the matter to eliminated. In order to obtain a particularly firm seat of the plug 4 inside the envelope 5, it is further preferred that the central aperture 7 be tapered outwardly from the end 12 towards the closed end II. The tapered end overlaps the outer end face 13 of the plug 4 and maintains the latter firmly clamped. Obviously such an embodiment cannot be produced by simple drilling or stamping of cylindrical sections from polyvinyl acetal foam plastics material; in this case it is necessary to fabricate the envelopes piece by piece by expansion in an appropriate mould.

The envelope 5 is provided with a retrieval thread 8, by means of which the envelope with plug 4 can be extracted from the bowel outlet when required. The retrieval thread can be fixed to the envelope in any desired manner. It has, however, been found particularly favourable to draw the thread throught the envelope in a doubled loop namely in such a way that two arms 14 and 15 of thread extends parallel to each other and also to the central aperture 7. The two thread arms are closed into a loop at the end 11 by a thread bridge 16, the thread bridge 16 being drawn into the soft foam plastics material so that it is invisible or at least inconspicuous from the outside. The two thread arms 14 and 15 are joined together at the outlet end, e.g. by a knot 17. The retrieval thread is preferably made of cotton; however, other materials, such as nylon etc., may likewise be used.

Making the envelope 5 of open-cell polyvinyl acetal foam which is known per se, has particular advantage in the present closure, as it has been discovered that this material, in the dry state, is immune to attack by bacteria, fungi or other microorganisms. The material in the dry state is comparatively hard, but it can be softened up in a short time by simply wetting it with water, whereupon it changes into a risiliently elastic rubber-like state.

After the softening water evaporates, the foam becomes hard again. This rehardening is undesirable in the present context, and it is therefore proposed to use the following solution as a softening fluid: Distilled water 40 Weight % Proplylene glycol-1.2 20 Weight % Ethyl alcohol 39.5 Weight % Glycerine 0.5 Weight % When the polyvinyl acetal foam is softened by using such a solution, it remains elastic for a practically unlimited period. The propylene glycol and glycerine content of the solution make it possible for the envelope to be inserted into the bowel outlet easily and without disagreeable irritating friction.

It has been found advantageous if the inner surface of the envelope 5 of polyvinyl acetal foam is waterproofed. By this means the liquid adsorptivity of the plug can be limited without thereby impairing the desired elasiticity and softness. The inner surface of the envelope may be waterproofed in any desired manner. However it is preferred to use silicones for waterproofing because they have been found to be particularly nonirritant and highly compatible.

It is also possible to waterproof the polyvinyl acetal foam chemically, namely by not using formaldehyde, acetaldehyde or other short-chain aliphatic aldehydes as the acetalfoaming aldehyde, as is customary, but by using long-chain aliphatic aldehydes, such as e.g., stearylaldehyde or the like. Due to the incorporation of these long molecular chains, the otherwise hydrophilic polyvinyl acetal foam assumes more or less hydrophobic properties, the degree of waterproofing can be adjusted by appropriate choice of the chain length.

The present bowel closure envelopes can be produced and packed sterile in the dry state without an inserted plug. When it is required to use the envelope, the user removes it from the package and softens it in water or in a suitable solution, e.g., with the above-stated composition. The envelope then changes into the desired elastic state in a few minutes. In this state the plug, which consists either of magnetisable or permanent magnetic material, can easily be inserted, while the envelope is generally slightly compressed inside. In the case of an embodiment with a tapered end 12, it is easily possible to force the magnet into the inner cavity and to make the tapered end snap over outside. In this state the resulting closure is inserted into the bowel outlet 2, when it slides into the correct position shown in Figure I due to the reciprocal magnetic effect with the ring magnet 3.

WHAT WE CLAIM IS: 1. A closure device for an artificial bowel outlet with a ring magnet implanted at the bowel outlet, wherein the closure device comprises a plug made of permanent magnetic or soft magnetisable material mounted in an envelope made of open-cell polyvinyl acetal foam.

2. A closure device as claimed in claim 1, wherein the interior surface of the envelope of polyvinyl acetal foam is waterproofed.

3. A closure device as claimed in claim 2.

wherein the inner surface of the envelope is waterproofed with a silicone.

4. A closure device as claimed in any one of claims I to 3, wherein the envelope consists of an at least approximately cylindrical sleeve which is formed with a longitudinally axial central aperture and wherein the envelope is provided with a retrieval thread.

5. A closure device as claimed in Claim 4, wherein said sleeve is thickened at its ends.

6. A closure device as claimed in claim 4.

wherein the diameter of the central aperture is smaller than the diameter of the magnetic plug to be introduced therein.

7. A closure device as claimed in any one of Claims 4 to 6, wherein the central aperture is closed at one end.

8. A closure device as claimed in Claim 7, wherein the central aperture is tapered outwardly towards the closed end.

9. A closure device for an artificial bowel outlet with a ring magnet implanted at the bowel outlet substantially as hereinbefore described with reference to Figure 1 alone or as modified by either of Figures 2 and 3 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. to use silicones for waterproofing because they have been found to be particularly nonirritant and highly compatible. It is also possible to waterproof the polyvinyl acetal foam chemically, namely by not using formaldehyde, acetaldehyde or other short-chain aliphatic aldehydes as the acetalfoaming aldehyde, as is customary, but by using long-chain aliphatic aldehydes, such as e.g., stearylaldehyde or the like. Due to the incorporation of these long molecular chains, the otherwise hydrophilic polyvinyl acetal foam assumes more or less hydrophobic properties, the degree of waterproofing can be adjusted by appropriate choice of the chain length. The present bowel closure envelopes can be produced and packed sterile in the dry state without an inserted plug. When it is required to use the envelope, the user removes it from the package and softens it in water or in a suitable solution, e.g., with the above-stated composition. The envelope then changes into the desired elastic state in a few minutes. In this state the plug, which consists either of magnetisable or permanent magnetic material, can easily be inserted, while the envelope is generally slightly compressed inside. In the case of an embodiment with a tapered end 12, it is easily possible to force the magnet into the inner cavity and to make the tapered end snap over outside. In this state the resulting closure is inserted into the bowel outlet 2, when it slides into the correct position shown in Figure I due to the reciprocal magnetic effect with the ring magnet 3. WHAT WE CLAIM IS:

1. A closure device for an artificial bowel outlet with a ring magnet implanted at the bowel outlet, wherein the closure device comprises a plug made of permanent magnetic or soft magnetisable material mounted in an envelope made of open-cell polyvinyl acetal foam.

2. A closure device as claimed in claim 1, wherein the interior surface of the envelope of polyvinyl acetal foam is waterproofed.

3. A closure device as claimed in claim 2.

wherein the inner surface of the envelope is waterproofed with a silicone.

4. A closure device as claimed in any one of claims I to 3, wherein the envelope consists of an at least approximately cylindrical sleeve which is formed with a longitudinally axial central aperture and wherein the envelope is provided with a retrieval thread.

5. A closure device as claimed in Claim 4, wherein said sleeve is thickened at its ends.

6. A closure device as claimed in claim 4.

wherein the diameter of the central aperture is smaller than the diameter of the magnetic plug to be introduced therein.

7. A closure device as claimed in any one of Claims 4 to 6, wherein the central aperture is closed at one end.

8. A closure device as claimed in Claim 7, wherein the central aperture is tapered outwardly towards the closed end.

9. A closure device for an artificial bowel outlet with a ring magnet implanted at the bowel outlet substantially as hereinbefore described with reference to Figure 1 alone or as modified by either of Figures 2 and 3 of the accompanying drawings.