A reflection on the use of convex appliances

12 June 2023
A reflection on the use  of convex appliances
A reflection on the use of convex appliances - Hollister LTD

Jo Sica and Lesley Law discuss how convex pouching systems can help prevent leakage and protect the skin for individuals with stomas, explaining the different types of convex skin barriers available and why it is important to seek guidance to find the right system for your needs

Convex stoma pouches have been available since 1986 (Colwell, 2016). They are designed to help create a better seal around the stoma, which can help to prevent leaks. Convexity refers to the
dome-shaped skin barrier on the pouch. Convex appliances come in various plateau sizes, cut to fit and pre-cut, so you can find one that is right for you.

A convex skin barrier should aim to provide a leak-free seal. The barrier should cause the stoma to protrude by providing tension to the skin around the stoma. This can be done by using a convex skin barrier, which is a type of skin barrier that has a dome-shaped centre. The convexity of the barrier helps to lift the stoma and create a more secure seal.

Soft convex systems offer a higher degree of compressibility, meaning that they are often more comfortable for ostomates to wear. This is because they are less likely to irritate the skin around the stoma. Soft convex systems are also more flexible, which means that they can conform to the shape of the abdomen more easily.

Convex uses

Convex skin barriers have long been used to create a secure seal for stomas that don’t protrude from the skin.

By applying tension to the skin around the stoma, these barriers prevent leakage and protect the skin. However, recent advancements in technology have led to the development of more flexible and compressible barriers, which can be used to prevent leakage and skin damage in the immediate postoperative period. This can have a positive impact on the individual’s psychological well-being.
Convex barriers are suitable and effective in obtaining a secure seal in the following scenarios:

  • When a stoma doesn’t protrude
  • To flatten out abdominal creases and folds
  • Stomas that sit in dips
  • To flatten out abdominal contours
  • To prevent silent seepage underneath the barrier.

There are many types of convex skin barriers available, with some offering a high degree of compressibility and others having a harder, less compressible convex plateau. A stoma care nurse can provide guidance on the most appropriate system based on the individual’s stoma and taking into account the factors mentioned above.

Case scenario

A 57-year-old woman with ulcerative colitis managed her condition with steroids for over 20 years. Eventually, she required surgery and an end ileostomy. Despite using a flat-backed pouch with a seal, she experienced leakage and seepage around the stoma appliance aperture, which affected her confidence and quality of life.

The patient’s stoma was well-spouted, but her flaccid abdomen made it challenging to find a secure pouch. Her community stoma nurse suggested trying a soft convex pouch, taking into account the varying consistency of her ileostomy output and her active lifestyle, which included swimming
and walking.

The primary characteristics considered when choosing a stoma appliance were depth and tension location. The convex dome provided gentle pressure within the correct tension location, flattening and smoothing the peristomal plane to ensure a secure seal.

After just a week of using the new pouch, the patient expressed feelings of security and confidence. Her peristomal skin had improved, and the appliance was no longer leaking, providing her with the peace of mind she needed to enjoy her daily activities.

This case highlights the importance of finding the right stoma appliance to meet an individual’s unique needs. With the help of a knowledgeable stoma care nurse, patients can find a solution that works for them and improves their quality of life.


Convex pouching systems are a valuable tool in addressing many issues, particularly leakages. By ensuring a pouch fits well, many skin issues can be prevented. It’s widely recognised by healthcare professionals and ostomates alike that leakages not only cause sore skin but can also significantly impact an individual’s confidence.

The newer, more compressible and flexible convex barriers are often more comfortable as they mirror the shape of the abdomen and move with the person as they go about their daily life. However, it’s important to note that convex pouches may require additional stoma accessory products, such as a belt to ensure the convexity is held close to the body or a seal/washer to help enhance the seal close to the stoma.

If you’re considering using a convex pouch or would like to try a convex system, it’s essential to seek advice from a stoma care specialist nurse. They can provide guidance on the most appropriate system based on your unique needs and help you find a solution that works for you.

Anyone using a convex pouch or even those who would like to try a convex system should seek advice from a stoma care specialist nurse.

Colwell J. Selection of pouching system. Ostomy Management. 2016. In: Wound Ostomy Continence Nurses Society Core Curriculum. New York: Wolters Kluwer; 2006