Introduction 30% of Ulcerative Colitis (UC) patients require surgery. Restorative procto-colectomy (RPC) with ileal pouch-anal anastomosis (IPAA) is the preferred procedure. Published experience suggests up to 25% of patients subsequently manifest Crohn’s Disease (CD), and 50% of these require pouch excision. Despite long-term follow up, we had not previously identified Crohn’s conversion in our UC pouch patients.

Aim We analysed our UC cohort, for cases where the pouch was either excised or de-functioned. The aim of this study was to quantify the incidence of CD in this group.

Methods All children undergoing pouch surgery have had data regarding their surgery, pre-op management and disease status recorded contemporaneously. This database was interrogated and further results from the histology database retrieved. In addition, pre-pouch surgery work up, specifically diagnosis and number of pre-op colonoscopies, was evaluated.

Results From 1999 to 2020, 84 children (mean age 13.5 yrs) have undergone surgery for UC with the intention of performing RPC and IPAA. 3 were unable to be anastomosed at initial surgery; 1 subsequently underwent successful IPAA, 2 have end ileostomies.

10 patients have had their pouch excised. The excised pouch did not demonstrate CD. 4 were excised for poor function, 3 for pelvic sepsis, 2 for faecal incontinence and 1 for bleeding. 3 of the 10 subsequently underwent successful revision pouch surgery. 4 other patients are currently diverted with an ileostomy (2 because of complications in pregnancy).

We have not identified CD developing in previous UC in our cohort. No children with a diagnosis of indeterminate colitis underwent RPC and IPAA. Children with the diagnosis of indeterminate colitis on initial histology had a subsequent diagnosis of UC on imaging or histology before surgery. The median number of pre-colectomy endoscopies performed was 3.

Summary and conclusion At median follow up of 10 years, we have not seen a conversion of diagnosis from UC to CD. This contrasts with published experience.