OSTOMY BAGS
This invention relates to improved ostomy bags and in particular to improved methods for securing an ostomy bag to the body of a patient.
Background of the Invention According to UK Department of Health Statistics, about 80,000 people in the UK have stomas of various types. The operation that creates a stoma, known as an ostomy, involves the division of the bowel and the joining of the ends to the body surface either as loop or end stoma. Common bowel conditions that may require stoma formation include carcinomas, Crohn's disease and trauma of various types.
As is well known, there are several different types of ostomy operation:
• Colostomy: creating an opening for the large intestine or colon on the wall of the abdomen.
• Ileostomy: creating an opening for the small bowel on the wall of the abdomen. • Urostomy: creating an opening for the urinary duct on the wall of the abdomen.
Numerous appliances for collecting bodily discharges from patients with stomas have been developed and are in widespread use. Such appliances typically comprise a bag or pouch for receiving liquid, solid or semi-solid waste from the stoma, together with a means for securing the bag to the body of the patient about the stomal opening. One commonly used method of securing the ostomy bag to the body of the patient is to use an adhesive flange or plate that is fixed around the stoma in order to attach the appliance securely to the skin.
Many ostomy bags in current use make use of hydrocolloid adhesives. One form of hydrocolloid adhesive comprises powdered gelatin, pectin and cellulose in a polyisobutylene (PIB) matrix. The powdered gelatine, pectin and cellulose absorb moisture and gel within the matrix. An adhesive flange of this type can be formed
by mixing together PIB and powder components for a period of about 45 minutes at 60 to 75 °C and then extruding the mixture for further processing.
Hydrocolloid adhesives have proved to be very effective for use with colostomy patients. The hydrocolloid forms a good bond to the skin for the period over which the colostomy bag is in place, and is very skin-friendly, causing negligible adverse skin reactions.
In the case of colostomy bags, where the waste received from the stoma is of a more solid nature, the moisture absorbed by the hydrocolloid will be mainly water lost through the skin by transpiration. However, in the case of ileostomy and urostomy bags, additional factors have to be considered. Since the output from the stoma is more liquid, and the edge of the hydrocolloid is exposed around the stoma, the fluid from the stoma and in the bag will be absorbed laterally by the hydrocolloid causing the hydrocolloid to swell progressively until a point is reached where the hydrocolloid begins to dissolve and break down. As the hydrocolloid dissolves, so the adhesion between the adhesive pad and skin of the patient progressively diminishes until there is no longer sufficient adhesion to adhere the medical device to the patient.
Some hydrocolloid adhesives ("integrated hydrocolloid") contain a cross-linked matrix which swells rather than dissolves but a problem here is that once the liquid absorbent capacity of the matrix is exceeded, the adhesion to the patient fails shortly thereafter.
The loss of integrity of the adhesive flange not only allows dissolved hydrocolloid to leak into the stomal wound but also allows urine and mucus to leak under the flange causing maceration of the skin and soiling of the patient's clothing.
One solution to this problem is to increase the absorbent capacity of the adhesive flange by increasing the thickness of the hydrocolloid layer. For example, whereas a colostomy pouch might be provided with a 0.6 mm thick layer of hydrocolloid, an ileostomy pouch may require a 0.9 mm thick layer of hydrocolloid and a urostomy pouch a 1.8 mm thick layer of hydrocolloid.
Although effective in many respects, increasing the thickness is a rather crude approach to the problem and is not a very cost effective solution, since larger amounts of material are required. Furthermore, some patients have difficulty with cutting the thicker flanges to fit their stomas, and the thicker flanges can be less comfortable to wear.
Another approach is to provide a means of shielding the hydrocolloid adhesive from contact with fluids draining from the stoma and this approach is illustrated in GB 2277031 (Welland Medical) which discloses an adhesive flange comprising a radially inner ring of erosion-resistant material and a radially outer ring of an adhesive material, the inner ring being arranged to shield the outer ring from bodily waste passing out of the stoma. The erosion-resistant material is described as being preferably a polymer foam such as a polyethylene foam or a polyurethane foam.
A similar approach is described in GB 2283916 (Welland Medical) which discloses an adhesive flange comprising a backing layer on which is mounted a ring of a hydrocolloid or hydrogel adhesive arranged concentrically between inner and outer rings of an adhesive such as an emulsion acrylic adhesive. The seal between the backing layer and the patient's skin created by the inner ring of adhesive prevents stomal waste from coming into contact with the hydrocolloid or hydrogel adhesive.
US 4714465 (Craig Medical Products) discloses an ostomy bag provided with an adhesive flange in which a flexible skirt encircles the stomal aperture and prevents leakage of urine towards the adhesive. There is no disclosure in US 4714465 as to the particular materials from which the flexible skirt is formed.
EP 0317326 (Hollister inc.) discloses an ostomy bag in which a microporous patch coated with a pressure sensitive adhesive such an acrylic adhesive is used to adhere the ostomy bag to the patient's body. A multilayer convex structure surrounding the stoma provides a seal. The convex structure has an outer surface layer of a moisture-absorbing skin barrier material which has both dry and wet tack.
US 3878847 (Marsan) describes a membrane for positioning between an ostomy bag and a patient's skin, to prevent leakage of stomal waste. The membrane has an
aperture designed to fit snugly around the stoma. The membrane can be formed from a variety of materials, one example of which is silicone rubber.
GB 2115291 (Matburn Holdings) discloses an ostomy bag in which a micro-porous flange bearing an adhesive described as being "non-occlusive" is used to adhere the ostomy bag to the skin of a patient. A mounting ring formed from a gas and liquid- impermeable material prevents the contents of the bag from leaking through to the micro-porous material, and an inner adhesive layer bonded to the mounting ring serves to provide adhesion to the patient's skin around the stoma. The inner adhesive layer is preferably a hydrophilic polymer of the type disclosed in GB 2046764.
The present invention relates to improved adhesive flanges which have good bioadhesive properties, are skin-friendly, and which retain their integrity in the presence of liquid exudates from a stoma.
Summary of the Invention In a first aspect, the present invention provides an adhesive flange for securing an ostomy bag to the body of a patient about a stomal opening; the adhesive flange comprising a support member having secured to one side thereof an ostomy bag or means for connection to an ostomy bag, and having on the other side thereof a layer of a water-degradable bioadhesive (e.g. a hydrocolloid adhesive or hydrogel adhesive) for securing the support member to the body of the patient; the support member and bioadhesive layer having an aperture for locating about the stomal opening and through which stomal waste can pass; characterized in that the aperture is lined with a water repellent material selected from silicones and non-foamed polyurethane that prevents or inhibits lateral migration of water into the bioadhesive layer.
The present invention also provides an adhesive flange for securing an ostomy bag to the body of a patient about a stomal opening; the adhesive flange comprising a support member having secured to one side thereof an ostomy bag or means for connection to an ostomy bag, and having on the other side thereof a layer of a
water-degradable bioadhesive (e.g. a hydrocolloid adhesive) for securing the support member to the body of the patient; the support member and adhesive layer having an aperture for locating about the stomal opening and through which stomal waste can pass; characterized in that the aperture is lined with a moisture barrier formed from a water repellent material selected from silicones and non-foamed polyurethane to shield the bioadhesive layer from liquid stomal waste.
The bioadhesive is one which is degraded by water and urine. The term "degraded" as used herein means that the bioadhesive loses its capacity to function as an adhesive after prolonged contact with excess water. For example, the bioadhesive may lose its structural integrity and may disintegrate after being in contact with water for a prolonged period. Alternatively, for example in the case of "integrated hydrocolloids", the bioadhesive may absorb so much water that the liquid absorbing capacity of the hydrocolloid is exceeded and the adhesive properties of the hydrocolloid are diminished or lost.
Typically, the bioadhesive is a hydrocolloid adhesive or hydrogel adhesive
Examples of hydrocolloid adhesives are the hydrocolloid adhesives of the type described above in the introductory paragraphs of this application.
Examples of hydrogel adhesives are water-swellable cross-linked polymers such as cross-linked polyacrylamide gels; polymers containing cross-linked polymer chains derived from styrene, isoprene, cyclopentadiene and dioctyl adipate monomers; and polyhydroxy ethyl methacrylic acids. Alternatively, gel-forming natural and modified polysaccharides can be used.
The water repellent material is typically a polymer such as a silicone or a non- foamed polyurethane. The silicone may be one which has adhesive (e.g. lightly adhesive) properties thereby providing a more effective seal around the stoma.
The silicone is preferably a polysiloxane. Preferred polysiloxanes include polydimethylsiloxane and co-polymers thereof. The polydimethylsiloxane is typically cross-linked by addition curing, for example with a platinum catalyst. One example of a polydimethyl-siloxane suitable for use in the adhesive flanges of
the invention is the two part silicone product sold by GE Bayer of Leverkusen, Germany, under the trade name TP3904.
The water repellent material acts as a moisture barrier to prevent or inhibit moisture from migrating from the stoma into the water degradable (e.g. hydrocolloid adhesive). The water repellent material can be presented in the form of an annular body or insert (e.g. a moulded insert) that is seated in the aperture in the bioadhesive (e.g. hydrocolloid) layer.
Typically, all or the greater part of the annular body is disposed in concentric contiguous relationship within the aperture in the bioadhesive layer. Preferably, the annular body has a radially outwardly facing surface that abuts (and typically seals) against a radially inwardly facing surface of the aperture in the bioadhesive layer around substantially the entirety of the circumference of the radially inwardly facing surface.
In one embodiment, the insert can have a central aperture through which the stomal waste can pass, and a radially outwardly facing surface for sealing against and protecting a radially inner surface of a hydrocolloid adhesive flange.
The insert (e.g. moulded insert) typically has a portion (e.g. a portion having a radially outwardly facing surface) for lining the aperture (e.g. a radially inwardly facing surface thereof) and a flange portion that overlies a portion of the body-side surface of the hydrocolloid layer. Alternatively, or additionally, the insert (e.g. moulded insert) may have a flange portion that overlies a portion of the bag-side surface of the hydrocolloid adhesive or the support member.
The insert can be provided separately for use with ostomy bag adhesive flanges, or it can be incorporated into the adhesive flange during manufacture.
In one embodiment, the insert is formed (e.g. moulded) separately and then inserted into an aperture in the bioadhesive (e.g. hydrocolloid adhesive) layer.
In an alternative embodiment, the insert can be die cut from a sheet of a suitable silicone or polyurethane material and then inserted into an aperture in the bioadhesive (e.g. hydrocolloid adhesive) layer.
In a further alternative, the insert can be moulded in situ by pouring a curing or curable silicone or polyurethane or precursor(s) thereof into a central aperture formed in a layer of hydrocolloid adhesive, optionally using one or more moulding elements to constrain flow of the curable silicone or polyurethane or precursor thereof, and allowing curing to take place.
The insert can be die cut to a particular size so as to fit a particular size of stoma, and an adhesive flange may be provided with several inserts of differing sizes so that a patient can select an insert of the appropriate size. Where necessary, the patient can cut the aperture in the adhesive flange to the required size and then fit the appropriately sized insert.
In an alternative, the insert can be formed from a material that is deformable (e.g. plastic) but has negligible elastic memory so that its shape can be adjusted in situ to fit about the stoma of the patient without the need for cutting.
The insert may be substantially planar in the region in which it comes into contact with the skin of the patient, or it can have a convex formation extending in the direction of the patient's body for applying pressure to the region around the stoma. This may be beneficial in achieving a better seal between the patient's skin and the ostomy bag flange, particularly when the stoma is retracted or the peristomal area is uneven.
The support member typically takes the form of a moulding or film layer to which the hydrocolloid adhesive is applied. The support member may have an ostomy bag secured (for example by adhesive or by welding (e.g. r.f. welding) to one side thereof. Alternatively, the support member may be provided with means for attachment of an ostomy bag, for example when the ostomy bag flange is of the "two-piece" variety comprising separable "body-side" and "bag-side" flange members, the adhesive flange of the invention constituting or forming part of the
"body-side" flange member. Such attachment means can be mechanical, for example an array of ridges and/or grooves on the "bag-side" surface of the support member that interlock with grooves and/or ridges on a "bag-side" flange" to which the bag is attached. Alternatively, or additionally, the attachment means can be adhesive.
In a further aspect, the invention provides an ostomy bag comprising an adhesive flange as defined herein.
Brief Description of the Drawings
Figure 1 is a perspective view of an adhesive flange according to one embodiment of the invention.
Figure 2 is a sectional view along line I-I in Figure 1 but additionally showing part of an ostomy bag attached thereto.
Figures 3a, 3b, 3b-l, 3b-2 and 3c show a separate moisture barrier insert, its insertion into a hydrocolloid flange and the resulting composite structure.
Figure 4 is a cross sectional elevation of an insert according to another embodiment of the invention.
Figures 5 a and 5b are schematic cross sectional elevations illustrating the stages in the construction of an adhesive flange according to a further embodiment of the invention.
Figures 6a and 6b are schematic cross sectional elevations illustrating the moulding in situ of a silicone insert in an adhesive flange according to another embodiment of the invention.
Detailed Description of the Invention
The invention will now be illustrated in greater detail, but not limited, by reference to the specific embodiments illustrated in the drawings.
As shown in Figures 1 and 2, an ostomy bag flange according to the invention comprises a support member 2 to which is bonded a layer 4 of a hydrocolloid adhesive. Usually, the hydrocolloid layer will be provided with a protective release layer (not shown) to prevent damage and soiling of the adhesive prior to use. The support member in this embodiment is a layer of thermoplastic film such as polyethylene film. Secured to one side of the support member 2, for example by welding, is one wall of an ostomy bag 6. The ostomy bag may be of conventional form and can be formed of a polymeric film of a type well known for the construction of ostomy bags.
The support member 2 and hydrocolloid layer 4 have a central aperture 8 through which waste from the stoma of a patient can pass. In order to protect the hydrocolloid from the degradative effects of liquid from the stoma, the flange is provided with an insert 10 moulded from a silicone material. The insert 10 has a main portion 12 that lines the inner surface of the aperture 8, and a flange portion 14 that overlies part of the body-side surface of the hydrocolloid layer. The insert 10 acts as a moisture barrier that prevents liquid from the stoma from coming into contact with the hydrocolloid adhesive.
The moisture barrier can be formed and supplied integrally with the adhesive flange or it can be formed separately. Where it is formed separately, it can be inserted into an adhesive flange as part of the manufacturing process or it can be presented separately for insertion by a patient or medically qualified person at the point of use.
Figure 3a shows a separately formed insert 30, which in this embodiment, is formed from a slightly adhesive grade of silicone rubber. The adhesiveness of the silicone rubber helps to provide a better seal against the peristomal region surrounding the patient's stoma. As with the embodiment of Figures 1 and 2, the insert has a central aperture 32 through which the stomal waste can pass, and a radially outwardly facing surface 34 for sealing against and protecting the inner surface of a hydrocolloid adhesive flange. Flange 36 in use overlies part of the body-side
surface of the adhesive flange thereby providing further protection against liquid from the stoma.
Figure 3b-2 illustrates the insertion of the moisture barrier insert 30 into the hydrocolloid flange 38.
Figure 3b- 1 illustrates a moisture barrier insert generally similar to that of Figure 3b-2, in that it has a radially outwardly facing surface 44 for engaging and sealing against the inner edge 52 of an aperture in the hydrocolloid flange 50, and a flange 42 which overlies part of the body-side surface of the adhesive flange. However, it differs from the insert of Figure 3b-2 in that it also has a smaller flange 46 which overlies part of the opposite side (bag-side) of the hydrocolloid flange. The flanges 42 and 46 define a groove in which the edge of the hydrocolloid can be seated, the two flanges providing even more protection against the degradative effects of liquid form the stoma.
Figure 3c illustrates the adhesive flange and insert in an assembled state.
Figure 4 shows a section through an adhesive flange according to another embodiment of the invention. In this embodiment, the insert has a cylindrical portion 62 having a radially outwardly facing surface 64 which engages the inner surface 68 of an aperture in hydrocolloid adhesive flange 66. Flange 70 on the insert 60 in use overlies a portion of the body-side surface of the hydrocolloid flange. However, the insert 60 differs from the inserts of Figures 1, 2, 3a, 3b- 1 and 3b-2 in that it has a convex formation 72 extending away from the cylindrical portion 62. The convex formation 72 has a central aperture 74 surrounded by a rim 76. In use, the convex formation 72 applies gentle pressure against the peristomal region thereby providing a better seal between the adhesive flange and the patient's skin and hence further reducing the likelihood of leakage of liquid into the region between the hydrocolloid and the skin.
Figures 5a and 5b illustrate the construction of an ostomy bag flange according to another embodiment of the invention. In this embodiment, the adhesive flange comprises an annular body of hydrocolloid adhesive 102 which is adhesively
bonded to a polyethylene non- woven fabric layer 104. Arranged concentrically within the annular body of hydrocolloid adhesive 102 is an annular body or "washer" of silicone 106 mounted on a polyethylene non- woven fabric 108. The silicone "washer" is typically formed by die cutting from a sheet of cross-linked polydimethylsiloxane cast onto the polyethylene non woven fabric backing and the polydimethylsiloxane is typically one which has been cross linked by addition curing using a platinum catalyst. In this embodiment, the polydimethylsiloxane used can be the TP3904 products available from GE Bayer or Leverkusen Germany. Prior to casting the silicone washer 106 on the non- woven fabric layer, the non- woven fabric layer is treated with a silicone primer in order to facilitate bonding to silicone. The primer can be a low molecular weight silicone polymer such as polydimethysiloxane in a hydrocarbon solvent.
The silicone "washer" has a central aperture 110, through which waste can pass from a stoma into a bag (not shown) attached to the adhesive flange.
In order to secure the hydrocolloid layer 102 and the silicone layer 6 together, an annular layer of a weldable polymer 112 is welded to the polyethylene non- woven layers 104 and 108. The polymer washer 112 can be formed from any material capable of being welded to polyethylene and may, for example, be formed from polyethylene or ethylene vinyl acetate (EVA).
The weldable polymer layer 112 and the exposed region 104a of non- woven layer 104 not covered by the weldable polymer layer can in turn be welded to the bodyside wall of an ostomy bag or to the bodyside component of a two piece ostomy coupling.
The arrangement set out in Figures 5a and 5b is advantageous in regard to its simplicity and ease of construction, requiring only small number of fabrication operations.
Figures 6a and 6b illustrate the construction of an adhesive flange according to a still further embodiment of the invention.
In Figure 6a, a hydrocolloid flange 202 is provided with an aperture 210 either by moulding or by die cutting from a circle of hydrocolloid adhesive. On one side of the flange, the rim surrounding the aperture 210 is treated with a ring 220of silicone primer such as a low molecular weight polydimethysiloxane to facilitate bonding to silicone. A mould 212 comprising a central cylindrical portion 212a, an outer cylindrical portion 212b and a base plate 212c is then positioned in the aperture 210 of flange as shown in Figure 6a. A two part silicone mixture, for example the TP3904 polydimethysiloxane product described above, is then poured into the annular space 214 surrounding the central cylindrical portion 212a of the mould and allowed to cure.
After curing, the mould is removed, to give an adhesive flange as shown in Figure 6b in which silicone insert 216 is securely bonded to the adhesive layer.
In each of the foregoing embodiments, the insert can be constructed from a water repellent material, such as an appropriate grade of silicone, which has negligible elasticity but is deformable. This permits accommodation of stomas of varying sizes within the internal diameter of the insert by stretching the insert, rather than by cutting the insert to the required shape, an action which can be inconvenient and difficult for patients of impaired manual dexterity.
Equivalents It will readily be apparent that numerous modifications and alterations may be made to the specific embodiments of the invention described above without departing from the principles underlying the invention. All such modifications and alterations are intended to be embraced by this application.