Guidelines Updates

A statement on convexity use from ASCNUK

Date: 14 November 2025

A statement on convexity use from ASCNUK.

Dear member,

As you are aware, we, at ASCNUK, are intending to update our convexity guideline. We will do this through a working group of specialist nurses who will explore the literature, evidence and experiential input of the experts, Specialist Stoma Care Nurses. This working group has been facilitated in a consensus manner, seeking representation from varied specialist stoma care nurses who have expressed an interest in being included in the group. If you have not had an opportunity to join this group, there will be a chance to participate in peer review, so please keep this in mind when the group present their work.

We appreciate that this may take some time and that, in the interim, members may have some concerns regarding the use of convexity and need guidance; hence, we are issuing this statement from the Association.

ASCNUK supports the use of convex products, after an assessment by an expert specialist stoma care nurse (SSCN), in the immediate post-operative period if this is deemed to be necessary and if:

• The SSCN has made a thorough, complex clinical assessment,
• Including a dynamic risk assessment, in which all potential risks are appreciated,
• They have then rationalised that the use of convexity is of a lower risk of complication than to not use.

We do not advocate the use of convexity immediately post–operatively without the assessment of an expert specialist stoma care nurse, or indeed at any other time if a full complex assessment has not been made.

Our concerns are:

• Without assessment, complications may arise which will impact the patient and create clinical and legal repercussions for the SSCN
• If convexity is used without SSCN assessment, the specialist is immediately denigrated, potentially creating the impression that the role is non-essential and can be replaced with non-registered colleagues.
• The drive to improve surgeons’ techniques and their awareness of patients’ functional/aesthetic outcomes will diminish, further impacting ostomates of the future.

You can view the current convexity guideline here: https://ascnuk.org/wp-content/uploads/2024/05/convexity_guidelines_2021.pdf

 We, on no account, condone or support the application of a convex pouch in theatre, regardless of day of week or ward staff’s ‘training’.

We uphold the principles of safe practice set by the NMC for our registered nurses and are also responsible for safe , efficient and cost effective product use; whilst we do not make decisions based on cost, if that were to the detriment of clinical outcomes or experience, we are accountable for public resources, and the rise in convexity use should be for clinical reasons only.

We will endeavour to advocate for patients in our care and for the profession of specialist stoma care nursing and will challenge any practices that we feel compromise either group.

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