Ostomy appliance with inverted triangular faceplate and non-protruding pull tabs

An ostomy appliance is disclosed in which the adhesive faceplate for holding the appliance in place is of inverted triangular shape with rounded corners. The faceplate includes an adhesive layer composed of a hydrocolloid-containing pressure-sensitive adhesive, a protective release sheet removably covering the bodyside surface of the adhesive layer, and a flexible backing layer covering the opposite (pouchside) surface of the adhesive layer and permanently securing the faceplate to an ostomy pouch about the perimeter of a stoma-receiving opening. Because of its orientation, the triangular faceplate has one of its side edges extending across the upper end of the pouch (i.e., facing upwardly when the pouch is worn), resulting in a construction in which the area of the faceplate's adhesive layer is wider above the faceplate's opening than below it. In a preferred embodiment, the adhesive layer is recessed or set back at one of the faceplate's upper corners to provide both the release sheet and backing layer with non-protruding tab portions that facilitate both application and removal of the appliance.

BACKGROUND AND SUMMARY
 Conventional one-piece ostomy appliances, and the pouch components of
 two-piece adhesively-coupled appliances, generally consist of collection
 pouches equipped with adhesive faceplates of various shapes for adhering
 the appliances to the peristomal skin surfaces of patients or to the
 attachment surfaces of mounting rings adhesively secured to such
 peristomal surfaces. Most commonly, the faceplates have outer margins that
 are either generally round or square (with rounded corners) as shown, for
 example, in U.S. Pat. Nos. 5,403,299 and 4,213,458, although faceplates
 having other outlines are also known (see, for example, U.S. Pat. No.
 5,811,116). Regardless of its shape, such a faceplate essentially consists
 of an adhesive layer, preferably of a hydrocolloid-containing adhesive
 capable of absorbing moisture and having both wet and dry tack, and a
 backing layer of polymeric film or fabric covering the backside
 (pouchside) surface of the adhesive layer and securing the faceplate and
 pouch together about the stoma-receiving openings of the respective parts.
 In addition, a typical pouch faceplate assembly is supplied to the user
 with a removable release sheet that covers the bodyside surface of the
 faceplate's adhesive layer. To facilitate removal of the release sheet at
 the time of application, such a sheet is commonly provided with a tab
 portion that projects away from the periphery of the adhesive layer. In
 addition, the backing layer may also be provided with an outwardly
 projecting tab portion to assist a user in peeling the faceplate away from
 the skin (or from the attachment surface of a mounting ring) when removal
 of an appliance is desired (see U.S. Pat. Nos. 5,578,023 and 5,607,413).
 Where provided, such pull tabs almost always project upwardly, that is,
 towards the upper ends of the pouches, to render them more readily
 accessible in use, but such a location has offsetting disadvantages.
 Because of manufacturing requirements, the perimeter of a faceplate
 (including its tab portion) must necessarily be spaced inwardly from the
 periphery of the pouch on which the faceplate is mounted, with the result
 that a faceplate having upwardly protruding tabs must be located lower
 along the pouch wall than if such tabs were omitted. For any given size of
 pouch, that means that the provision of upwardly-projecting tabs reduces
 the effective volumetric capacity of the pouch. Also, the tab for a
 backing layer that extends upwardly away from the remainder of the
 faceplate may be exposed for possible contact with clothing and present
 the risk that such contact might initiate unintentional detachment of the
 faceplate from the skin.
 It is therefore a main aspect of this invention to provide an ostomy
 appliance having an adhesive faceplate shaped and oriented to provide more
 effective adhesive attachment where it is needed most in resisting pulling
 forces in use, while reducing the area of adhesive attachment in the lower
 region of a faceplate where excessive contact might cause pinching and
 other patient discomforts. More specifically, the faceplate of the
 appliance is of inverted triangular shape having rounded corners, with one
 of the corners facing downwardly towards the lower end of the pouch and
 one of its side edges facing upwardly along the upper end of the pouch.
 The result is an appliance having a faceplate of greater width in its
 upper region (i.e., above the midpoint of its stoma-receiving opening)
 than in its lower region, thereby providing greater adhesion where it is
 needed most, reducing the size of the faceplate in its lower region to
 promote greater patient comfort, and also limiting material volume and
 expense (recognizing that hydrocolloid-containing adhesive compositions
 constitute a significant portion of the cost of such appliances).
 Two of the rounded corners of the faceplate therefore face upwardly and
 outwardly and, in a preferred embodiment, both the removable release sheet
 and the backing layer of the symmetrical faceplate have non-protruding
 pull tabs along one of those corners. At such corner, the adhesive layer
 is set back or recessed to create a marginal corner area where the
 coextensive release sheet and backing layer, while following the regular
 marginal contour of the faceplate, have no adhesive material between them.
 Such adhesive-free portions therefore serve as pull tabs to facilitate
 removal of the release sheet at the time of application of the appliance
 as well as initiating detachment of the faceplate from the skin when
 removal is desired. Since the tabs are non-protruding--and especially
 because they are non-protruding in an upward direction--they do not
 interfere with close positioning of the faceplate to the upper margin of
 the pouch, thereby optimizing pouch volume. The fact that the tabs are
 non-protruding is also believed to reduce the possibility that movement of
 clothing or contact with other objects might initiate unintended
 detachment of the upper portion of the faceplate from the skin.
 While the provision of such non-protruding tabs reduces the adhesive
 material that would otherwise be available for contact with the skin (or
 with the attachment surface of a mounting ring adhesively secured to the
 skin), the inverted triangular shape of the faceplate nevertheless assures
 that the adhesive surface in the upper region of the faceplate (i.e.,
 above the midpoint of the faceplate opening) has greater width than in the
 faceplate's lower region and provides a substantial area of adhesion above
 and to the sides of the faceplate opening. Thus, the configuration and
 orientation of the faceplate optimize patient security while at the same
 time allowing for the provision of pull tabs along a portion of the upper
 margin of such a faceplate.
 Other features, objects and advantages of the invention will become
 apparent from the specification and drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
 Referring to the drawings, the numeral 10 designates an ostomy appliance
 consisting essentially of a pouch 11 and a faceplate 12. The drawings
 depict what may be referred to as a one-piece appliance, such term being
 commonly used to mean a unitary appliance having a faceplate intended to
 be adhesively secured directly to the peristomal skin surfaces of a
 wearer. It is to be noted, however, that at least some of the advantages
 of this invention might be obtained if used in a two-piece appliance in
 which the pouch and its adhesive faceplate are intended to be adhesively
 attached to (and detached from) the surface of a mounting ring which in
 turn is adhesively attached to such peristomal skin surfaces. Therefore,
 the term "appliance," as here used is meant to include not only a
 one-piece ostomy appliance but also the pouch/faceplate component of a
 two-piece adhesively-coupled appliance.
 Pouch 11 has upper and lower ends 11a and 11b, respectively and is
 typically composed of two panels or walls 13 and 14 of liquid and gas
 impermeable thermoplastic material heat sealed or otherwise secured
 together along their marginal edges 11c. One wall 13 (the bodyside wall)
 has a stoma-receiving opening 15 located in the upper portion of the
 pouch. The pouch as shown is of the drainable type with an opening 16 at
 its lower end that may be closed by means of a suitable clamping device
 such as, for example, the clamp shown and described in U.S. Pat. No.
 5,125,133. Alternatively, a pouch may be provided at its lower end with a
 suitable drain valve, especially if the pouch is intended for use as a
 urostomy appliance, or may be completely closed at its lower end as, for
 example, a colostomy pouch. It is to be understood that the symmetrical
 shape of the pouch as shown is not critical and that other pouch shapes
 commonly available and widely known in the art may be utilized. In
 addition, one or both outer surfaces of the pouch may be covered with
 soft, porous non-woven fabrics (not shown) to enhance patient comfort and
 reduce sound, all as known in the art.
 As shown in FIG. 1, faceplate 12 has the general shape of an inverted
 equilateral triangle with rounded corners. The faceplate is oriented so
 that one of its sides 12a faces upwardly, extending along and slightly
 below the upper edge portion 11a of the pouch. The opposing corner 12b
 faces downwardly towards the pouch's lower end 11b, and side corners 12c
 and 12d face upwardly and outwardly. A centrally-located opening 17
 extends through the faceplate and is concentric with the opening 15 in
 wall 13 of the pouch. In the embodiment illustrated, opening 17 is a
 starter opening that may be cut with scissors to a larger size that
 matches the size and shape of a patient's stoma.
 The thin, flat faceplate comprises an adhesive layer 20 having pouchside
 and bodyside surfaces 20a and 20b, respectively. Most advantageously, the
 adhesive layer is formed of a soft, skinfriendly hydrocolloid-containing
 adhesive material that is capable of absorbing moisture and has both wet
 and dry tack. Such a material is commonly referred to as a skin barrier
 composition and typically comprises a continuous elastomeric adhesive
 phase having hydrocolloid particles dispersed throughout the continuous
 phase. Initial tack, usually referred to as "dry tack," is provided by the
 continuous phase but, because such a composition is occlusive or
 non-breathable, adherence to the skin would be disrupted by perspiration
 and by liquid stomal discharge if it were not for the dispersed
 hydrocolloids which absorb fluids and thereby maintain and possibly
 enhance adhesive attachment to the skin. U.S. Pat. No. 4,551,490 and other
 references identified therein disclose that suitable water-absorbing and
 swellable hydrocolloid gums may include sodium carboxymethylcellulose,
 pectin, gelatin, guar gum, locust bean gum, and the like. The elastomers
 used in the continuous phase may be polyisobutylene, natural rubber,
 silicone rubber, acrylnitrile rubber, and other elastomers known in the
 art to have similar properties. For flow resistance, shape-recoverability,
 and the capacity to retain integrity during swelling of the hydrocolloid
 component upon liquid absorption, the continuous phase may include a
 physically crosslinked elastomer such as a styrene-olefin-styrene block
 copolymer as disclosed in co-owned U.S. Pat. No. 5,492,943, the disclosure
 of which is incorporated by reference herein. A composition of that patent
 includes a blend of two viscoelastic adhesive elastomers, specifically
 high molecular weight polyisobutylene and a styrene block copolymer which,
 along with a plasticizer (preferably petrolatum) and a suitable tackifier
 and antioxidant, form a continuous phase in which the hydrocolloid
 particles such as sodium carboxymethylcellulose and pectin are dispersed.
 It is believed that other barrier compositions, also containing physically
 crosslinked elastomers or mixtures of such elastomers, such as those
 disclosed in U.S. Pat. No. 4,231,369, may also be used.
 The faceplate also includes a backing layer 21 covering all or most of the
 pouchside surface 20a of adhesive layer 20. The backing layer should be
 flexible and heat-sealable so that it may be permanently joined to pouch
 wall 13 by annular heat seal 22 extending around the stoma-receiving
 opening 15 of the pouch (FIG. 2). The backing layer may be in the form of
 a thermoplastic film such as polyethylene or other polyolefin and an
 elastomeric film, such as polyurethane or an ethylene methacrylate
 copolymer, is believed particularly suitable. Alternatively, the backing
 layer may be formed of a heat sealable fabric, such as a porous non-woven
 polyolefin or other heat-sealable fabrics having similar properties. It is
 also to be understood that, if desired, the backing layer 21 may be
 composed of two or more sub-layers with each sub-layer providing
 properties contributing to those of the backing layer as a whole.
 The bodyside surface 20b of the faceplate's adhesive layer 20 is covered by
 a removable release sheet 23 formed of a flexible but generally
 non-stretchable material such as siliconized paper or a siliconized
 polymeric material such as polyethylene terephthalate. Preferably the
 release sheet and the underlying surface of the adhesive layer 20 are
 dimpled or embossed, at least in their outer portions as shown in the
 drawings, although such dimpling or embossing may be omitted if desired.
 The purposes and advantages of such dimpling or embossing are disclosed in
 co-owned U.S. Pat. No. 5,811,116, the disclosure of which is incorporated
 by reference herein.
 In a preferred embodiment, the adhesive layer 20 is recessed or relieved at
 one of the upper corners of the faceplate to provide an edge 20c set back
 from the edges of the release sheet 23 and backing layer 21. The setback
 results in corner portions 23a and 21a constituting tab portions that are
 non-protruding to the extent that they do not alter the rounded triangular
 contour of the faceplate as a whole.
 In use of the appliance, the pull tab 23a of release sheet 23 is gripped
 between the fingers and the sheet is peeled away to expose the bodyside
 20b surface of adhesive layer 20 (FIGS. 3 and 4). The faceplate is then
 adhered to the peristomal skin surfaces 30 of a wearer with the pouch
 generally oriented as shown in FIGS. 1 and 2. During subsequent use, as
 the pouch becomes filled with liquid/solid waste, downward forces tend to
 be exerted in the general direction of arrow 31 (FIG. 2) but such downward
 pulling forces may be effectively resisted because of the inverted
 triangular shape of the faceplate and the relatively large area and wide
 extent of the upper adhesive surface of the faceplate.
 When removal of the appliance is desired, a user simply grips tab 21a of
 the backing layer 21 and peels the faceplate away from skin surfaces 30 as
 depicted in FIG. 5.
 While in the foregoing, we have disclosed an embodiment of the invention in
 considerable detail for puposes of illustration, it will be understood by
 those skilled in the art that many of these details may be varied without
 departing from the spirit and scope of the invention.