GB2045084A - Improvements in or relating to tubular devices - Google Patents

Abstract

A tubular percutaneous device suitable for fabricating a stomata in colostomates and ileostomates or ileal conduits for urinary diversions comprises a tube formed at least in part of a material comprising carbon or carbon- like material and having an integral flange portion which extends radially outwards of the tube from a position between the ends of the tube. The flange portion, preferably provided with fenestrations, assists location and anchoring of the device relative to a body wall. <IMAGE>

Description

SPECIFICATION Improvements in or relating to tubular devices This invention relates to a tubular device for use in percutaneous applications.

For patients suffering from complaints which require the surgical fabrication of a stoma, e.g.

colostomates and ileostomates, it has been the usual practice hitherto to lead the cut end of the intestine through the body wall, the end of the intestine then being stitched to the outer skin surface. In the resulting condition it is difficult to control the flow of egestate and there arises in consequence a risk of infection and skin irritation. In addition it is difficult to effect satisfactory attachment of ostomy appliances.

One proposal for overcoming at least some of the afore-described difficulties requires the provision of a ring of magnetic material which is coated with plastics to minimise the risk of infection and rejection by body tissues. The ring is implanted in the layer of fat beneath the skin and the cut end of the intestine brought through the centre of the ring and turned outwards for suturing to the skin surface.

There thus results a condition in which the flow of egestate may be restricted by placing a magnetic cap over the ring. Disadvantages of the sytem are that the cap does not always form an adequate seal against that portion of the intestine lying between the cap and the ring, with the result that skin irritation can occur. In addition it is found that with time the ring may tend gradually to sinkfurther below the skin surface thus rendering difficult the effective location of the magnetic cap.

In addition to conditions of the type where the intestine is cut and led to the body wall, similar problems may arise where it is reqired to make a urinary diversion in which, for example, the utethra, bladder, or ureter is led to the body wall, whether with or without the use of an ileal loop.

It is an object of the present invention to provide a device which assists in overcoming or mitigating at least some of the afore-described difficulties.

In accordance with one aspect of the present invention there is provided a tubular percutaneous device comprising a tube formed at least in part of a material comprising carbon or carbon-like material as hereinafter defined and having a flange portion integral with and extending radially outwards of the tube from a position between the ends of the tube.

By carbon-like material is meant a material which exhibits a degree of bio-compatibility comparable with that of carbon.

Pure carbon and various graphites may be used but for greater strength and resistance to tensile, shear and torsional loads it is preferred to use a high grade carbon such as vitreous carbon or pyrolitic carbon, or more preferably carbon fibre reinforced carbon composite material (known commonly as carbon-carbon composite material).

In addition to materials of the kind referred to in the preceding paragraph and all of which exhibit good bio-compatibility, use may be made of mate rials such as ceramics which also provide a biocompatibility similar to that of carbon. Human tissue will adhere well to such materials without causing extrusion or rejection.

The preferred material for the tubular percutaneous device, carbon-carbon composite, may be formed by one of several methods already well known in the materials art.

In one method, known as the resin or pitch char route, carbon fibre material is impregnated either with hot liquid pitch or uncured resin to form a matrix between the fibres. The resin is cured or the pitch hardened before the composite is heated to a sufficiently high temperature to convert the matrix into pure carbon. The resulting composite may be subjected to further impregnation and carbonisation cycles to increase the density and strength properties and provide the required degree of porosity.

In another method known as the chemical vapour deposition (CVD) method the carbon fibre material is placed in a suitable furnace and heated to a tempera- ture in excess of 800or whilst in a non-oxidising gas stream, such as a stream of nitrogen.

At this stage a carbon bearing organic gas, e.g.

methane, is passed into the furnace under controlled pressure and flow rates and the gas dissociates into its elemental constituents at the fibre surface thus depositing carbon and releasing hydrogen. In this manner a matrix of pure carbon is built up between the fibres to form the composite.

It is also possible to form a carbon-carbon composite material by a combination of the abovedescribed methods, carbon-carbon composite being made by the resin or pitch char route and further impregnation being carried out using the CVD route.

A percutaneous device of a material formed by the above methods may then be subject to conventional engineering operations, e.g. machining, drilling to produce the required shape. Additional fixtures, of carbon or other materials, may then be added e.g.

screws, pins and securing means.

The tubular percutaneous device may be formed wholly of carbon or like material, or either of said materials may be a coating layer provided in combination with, for example, a tubular element of metallic or plastics material. The metallic or plastics material may be provided to increase the strength or reduce the cost of the component, or to provide a substantially impermeable layer if in particular circumstancesthe degree of porosity required on the part of the carbon or like material to obtain good adhesion with human tissue is too great to give adequate resistance to permeation of urine or egestates through the tube wall. A metallic or high strength plastics layer is also of particular use as a strengthening component where the carbon or like material does not possess the high degree of strength provided by carbon-carbon composite material.

To facilitate effective location and anchoring of the prosthesis in the body wall, the flange portion may be provided with fenestration which assist anchor ing by allowing tissue ingrowth.

The flange portion may extend substantially at right angles to the length of the device, in the form of an annular disc, or, for example, may be frusto-conical in shape, or flared. Preferably it is formed by moulding in which case in particular the thickness of the flange may vary to provide the required strength and also preferentially shaped tissue location surfaces.

To assist in securing an intestine or other internal tubular body passage to the device, the device may be formed, preferably near to one end with retention means. Said means may be a peripherally extending ridge and/or depression against which the body passage may be brought to bear in frictional engage- ment or a series of small holes may be provided spaced at intervals around the periphery of the tube or base of the flange to assist suturing.

Suturing holes may be provided also in the flange portion.

An internal body passage may be secured to an inner end of the device such that urine or egestates are passed through the device in contact therewith, or the internal body passage may extend through the device to an outer end thereof. In either case, the body passage may be secured to an inner or an outer surface of the tube, but where the body passage extends to the outer end it is preferred that attachment is at an inner surface of the tube such that the outermost end of the tube is exposed and therefore able to provide an effective sealing surface for a suitable closure member.

Particularly in cases where an internal body passage is led through the device, the tube may optionally be provided with fenestrations to assist in location of the body passage by tissue ingrowth and also reduce the risk of necrosis of the tissue adjacent the device.

The porosity of the tube material is selected to ensure that there is no significant seepage of urine or egestates through the tube wall to such an extent as may cause irritation or infection.

The invention provides also a tubular percutaneous device comprising a tube of carbon or carbon-like material as hereinbefore defined and having a selected variation of porosity along the length of the tube and/or through the thickness of the wall ofthetube.

The device is preferably substantially circular in cross-sectional shape and typically has an internal diameter in the range 0.25 to 7 cm, wall thickness typically in the range 0.20 mm to 1.0 cm. and length typically 1 to 12 cm. depending on the requirements of a particular application.

The cross-sectional size and/or shape may vary along the length of the device. Typically it is preferred that where the tube is tapered the lumen of the tube tapers downwards towards the outer surface of the body wall when the device is in situ.

Several embodiments of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings in which: Figures 1 to 5 each show perspective views of ostomy devices in situ in a section of body wall, and Figure 6 shows a perspective view of a urinary conduit in situ in a section of body wall.

With reference to Figure 1, there is provided an ostomy device 10 implanted percutaneously through a a body wall 11 to form a permanent link between the cut end 12 of an intestine 13 and the body exterior.

The ostomy device is formed of moulded carboncarbon composite and comprises a circular crosssection tubular portion 14 of internal diameter typically in the range 1 to 7 cm, wall thickness typically in the range 2 to 3 mm, and length typically 1 to 8 cm, the dimensions being selected to suit the requirements of a particular application.

Each end of the tube is formed at its radially outer surface with a protruding annular ridge 15. The ridge at the inner end 14a of the tube provides an abutment to resist the sutured cut end of the intestine 12 slipping from the tube, and the ridge at the outer end 14b overlies the surface of the skin immediately surrounding the device. Small holes (not shown) may be provided near the ridge 15 at the inner end 14a to assist suturing.

Midway between its ends the tube 14 is formed integrally with a flange portion 16 of a diameter typically 50% greater than the outer diameter of the tube, and to assist anchorage by tissue ingrowth the flange portion is provided with ten uniformly spaced fenestrations 17. The flange portion has a thickness similar to the tube wall except adjacent the tube where its thickness increases progressively to give a smooth transition between the surfaces of the flange portion and the tube, and the flange portion generally lies in a plane substantially at right angles to the longitudinal axis of the tube.

As an alternative to suturing the end of the intestine, said end may be held firmly against the outer surface of the tube end 14a by means of a clip, and said clip may be additional to suturing.

By use of the aforedescribed percutaneous device in combination with a suitable closure member which seals against the outer end 14b of the tube, the stoma may be rendered continent. Alternatively the outer end of the tube may be arranged to project slightly above the skin surface (typically 1 to 1.5 cm) to facilitate attachment of a standard ostomy collection bag.

In a second embodiment of the invention, illustrated with reference to Figure 2, a percutaneous device 20 is constructed substantially as described in respect of the first embodiment except that fenestrations 21 are provided in the tube at both sides of the flange portion 22. This construction is particularly suitable where the intestine 23 is drawn through the lumen of the tube and attached directly to the skin outer surface 24. The outer end of the tube can then be sealed by a closure member which bears against the end of the intestine where it is supported by the outer end of tube 20. Alternatively a standard ostomy collection device may be utilised as above described.

The device 30 shown in Figure 3 is substantially identical to that of Figure 2 but the end of the intestine is secured to the inner surface of the outer end 30a without passing outwards around the end of the tube.

In the constructions illustrated in Figures 2 and 3 location of the intestine relative to the tube is assisted by the tendency of live tissue to grow into the fenstrations 20. In addition said fenestrations assist to reducevasculurisation difficulties and ren der the device less obstructive.

In a fourth embodiment of the invention, illustrated in Figure 4, an ostomy device 33 is constructed substantially similar to that shown in Figure 2 except that the outer end 34 of the device is formed in the outer surface thereof with an annular groove 35 for location of a clip-on closure cap or collection bag. In addition a circumferentially spaced series of suturing holes 36 are provided in the device between the groove 35 and outer end 34 for attachment of the end of an intestine.

The device is suitable for fabricating a stomata in colostomates and ileostomates, and ileal conduits for urinary diversions.

Figure 5 is illustrates yet another ostomy device.

The device 50 comprises a tubular portion 51 provided midway between its ends with an anchoring flange 52 substantially as described in respect of preceding embodiments. The outer end region 53 of the outer half 54 of the portion 51 is formed in the outer surface thereof with an annular groove 55 for location of a clip-on closure device or collection bag.

The inner half 56 of portion 51 is formed, midway between its inner end and the anchoring flange, with a a retention flange 57 provided with a series of circumferentially spaced suturing holes for location of an intestine end.

In this embodiment the tubular portion 51 is not provided with fenestrations and therefore provides a tubular passage through which egestates may pass.

In those cases where the intestine passes through the lumen of the tube and is secured to an outer end thereof, the intestine may, optionally, be secured also to the inner end region of the tube by suturing orthe use of clips.

In a sixth embodiment of the invention, illustrated with reference to Figure 6, there is provided a percutaneous urinary conduit 60 for linking the bladder 61 with the body exterior via an opening 62 in the body wall 63.

The conduit is of a flared shape, the cross-section of the conduit being substantially uniform over approximately one half of its length and in a second half of a flared shape which increases outwards in diameter to approximately twice that of the first half.

The overall axial length, thickness, and bore of the first half are of similar dimensions to those given in respect of the first embodiment of the invention, and the conduit is made of a carbon-carbon composite material.

The first half 60a of the tube constitutes an outer half embedded in the skin and the second, flared, half 60b provides location for the bladder wall. A flanged portion 61 is formed integrally with the tube 60 and positioned midway between the ends thereof.

Attachment of the bladder to the flared half may be by means of a suturing ring or clip or a combination of said means, and the end of the flared half may be provided with a series of circumferentially spaced small holes (not shown) to assist suturing.

Closure of the conduit may be by means of a closure member placed over or into the end of the first half 60a.

The flange portion 61 assists obtaining a satisfactory location of the conduit relative to the skin and body tissues, and this is further assisted by fenestrations 62 provided in the flange portion for the ingrowth of tissues.

In addition to attachment of the bladder to the outer end of the device, the bladder may be sutured or otherwise secured to the flared end of the tube so as to avoid subsequent undesirable distortion of the bladder wall in the region of the conduit.

Whilst it has been described that a closure member such as a stop or cap may be provided to seal the conduit, alternatively a standard collection bag may be attached to the outer half of the conduit. In a further alternative a pressure release mechanism or valve may be provided so that urine is released from the bladder into a collection bag only when a certain pressure is attained.

Particular reference has been made to the use of carbon-carbon composite because they display features which make them more preferable than other presently known materials for the construction of tubular percutaneous devices. That is, carboncarbon composites are found to contain a very low level of impurities, to display an inertness to body tissues and fluids, have a low density, can be readily sterilised, can readily be produced in a wide range of sizes and shapes, and can be formed with a selective variation of porosity in different regions of the formed device.

Claims (17)

1. Atubular percutaneous device comprising a tube formed at least in part of a material comprising carbon-or carbon-like material as hereinbefore defined and having a flange portion integral with and extending radially outwards of the tube from a position between the ends of the tube.

2. Atubular percutaneous device according to claim 1 wherein retention means is provided to assist in securing an internal body passage to the device.

3. A tubular percutaneous device according to claim 2 wherein said means comprises a ridge or depression which extends around the periphery of the tube.

4. Atubular percutaneous device according to claim 2 wherein said means comprises a series of holes provided at spaced intervals around the periphery of the tube to assist suturing of an internal body passage thereto.

5. Atubular percutaneous device according to any one of claims 2 to 4 wherein fenestrations are provided in that portion of the tube lying to an opposite side of the flange portion as the tube portion provided with the retention means.

6. Atubular percutaneous device according to any one of the preceding claims wherein the internal or external cross-sectional size of the tube varies along the length thereof.

7. A tubular percutaneous device according to any one of the preceding claims wherein the wall thickness of the tube varies along the length of the tube.

8. Atubular percutaneous device according to any one of the preceding claims wherein the flange portion extends outwards substantially at right angles to the length of the device.

9. Atubular percutaneous device according to any one of claims 1 to 7 wherein the flange portion is of a substantially frusto-conical shape.

10. Atubular percutaneous device according to any one of the preceding claims wherein the flange portion has a substantially circular periphery the diameter of which is substantially 50% greater than the maximum cross-sectional outer dimension of the tube.

11. A tubular percutaneous device according to any one of the preceding claims wherein the flange portion is provided with fenestrations.

12. Atubular percutaneous device according to any one of the preceding claims wherein the porosity of the carbon or carbon-like material varies along the length of the tube and/or through the thickness of the wall of the tube.

13. Atubular percutaneous device according to any one of the preceding claims comprising a tubular element which is coated with the carbon or carbon-like material.

14. A tubular percutaneous device according to claim 13 wherein the tubular element is substantially impermeable.

15. A tubular percutaneous device according to claim 13 or claim 14 wherein the tubular element is formed of metallic material to act as a reinforcement.

16. A tubular percutaneous device according to any one of claims 1 to 12 formed wholly of carbon or carbon-like material.

17. Atubular percutaneous device constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.