Human - Anatomy of an Ostomy Pouch Series: Part 3—What is an Ostomy Flange?

Anatomy of an Ostomy Pouch Series: Part 3—What is an Ostomy Flange?

By Victoria McCallum RN

 In part 2 of our Anatomy of an Ostomy series, we focused on the different types of ostomy pouches. You’ve selected a pouch: great! Now what? Today’s blog is all about the flange.  What is it? What kind do you need? What makes them so different?

 What is an ostomy flange?

The flange, also called a skin barrier or wafer, is the part of the ostomy appliance that adheres to your skin, protecting it from stool or urine. The flange is made of hydrocolloids, adhesives and polymers which absorb excess moisture from the skin to ensure the flange remains sticky. 


What kind of flange do you need?

How your stoma functions is a key factor when choosing a flange. A higher output ostomy (ileostomy) will benefit from extended wear flanges: these absorb less moisture from stool and contain a stronger adhesive. Low output ostomies (colostomy) often use regular wear flanges with a gentle adhesive. The shape of your abdomen/stoma are often the most important things to consider when choosing a flange.

 Flat flange

A flat  flange is just as it sounds- flat. The surface on the back of the flange is even throughout and flexible. This standard flange is a great choice for ostomates who have an even abdomen and protruding stoma.

 Convex flange

A convex flange has a curve on the underside, which applies a small amount of pressure to the skin around your stoma. When applying pressure, the convexity helps flatten the abdominal skin, thereby “popping” your stoma up higher. Convexity varies from light to deep which determines its depth and flexibility. This flange is helpful for ostomates with abdominal creases or a flat stoma that is flush with the skin. Did you know that stool coming from a flush stoma comes in contact with the inner edge of the flange more often causing the adhesive to break down sooner.  “Popping” the stoma above this edge will preserve the adhesive and increase your wear time.

 Concave flange

A concave flange has a curve on the top side; the opposite of a convex flange. This design adjusts around hernias or larger abdominal curves. The unique shape increases flexibility and skin contact over challenging contours, making it a good choice for an ostomate with an uneven abdomen.

 Why does the shape of your abdomen/stoma matter?

The flange sticks best when it's in full contact with the abdominal skin. Creases, curves, dips and bumps provide a sneaky place for stool to leak. Your nurse specializing in ostomy (NSWOC) may want to observe you sitting, standing and lying to determine which fit is best for your belly.

 An important fact to remember: your abdomen will change shape over time and with that your flange may need to change too. How will you know? If you are experiencing a leak greater than one every two days, or the flange wear time is getting less and less, get a NSWOC assessment.  

 What other differences are there?

Flanges come in a variety of options: cut-to fit, pre-cut or moldable, adhesive or click coupling.

Measure your stoma using the guide provided by your NSWOC or the one that comes you’re your ostomy supplies. You have the option to either use the cut-to-fit flange or you can order it pre-cut.

 A moldable flange opening is stretched to fit the stoma and offers a good option (along with pre-cut) if you have dexterity issues. The flange and pouch can connect with click coupling, like a Tupperware lid to its base, or with adhesive, much like the flange attaches to your skin. Adhesive coupling is recommended if you have trouble using a ‘click’ design.  

 Lifestyle tips

Everyone’s skin is different! Ostomates with oily/moist skin may need to change their flange more frequently. This also applies to other things that increases flange or skin moisture: for example, sweating, going swimming or being in a hot tub.   

 Avoid using any ointment under your flange. These will weaken the adhesive and increase risk of a leak. Creams are also to be avoided unless the cream has been specifically designed to not interfere with adhesion (e.g. 3M™ Cavilon™ Durable Barrier Cream).

 The skin hidden under your flange should look the same as the rest of the skin on your abdomen. This means no rash, itching or burning. Should you notice any of these things, contact a healthcare profession or NSWOC for guidance.

In part 3 of this series, we’ll look in more detail at the Ostomy Flange.

Read more in part 1 : Anatomy of a Pouch: One Piece vs Two Piece

Karen Laforet

Karen Laforet

Karen is an RN with over 30 years of experience in skin & wound management, health advocacy, & policy. She is an experienced writer on all things health-related.
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