Functional Outcomes of Transanal Ileal Pouch-Anal Anastomosis Compared to Laparoscopic or Open Ileal Pouch-Anal Anastomosis: a Multi-Center, Randomized, Parallel-Group, Non-Inferiority Trial

Background: Ulcerative colitis (UC) and inflammatory bowel unclassified (IBDu) are inflammatory bowel diseases (IBD) involving the colon and rectum. It is a chronic disease occurring in young people with a high burden on social and professional life. Although treated medically by immunomodulatory drugs, about 15 - 20% of UC patients will need an ileal pouch-anal anastomosis (IPAA). In primary cases, this procedure is usually performed laparoscopically (further called transabdominal IPAA or tabd-IPAA). More recently even less invasive surgical techniques have emerged, using a trans-anal access, facilitating dissection of the distal rectum. Although transanal access is associated with a good postoperative outcome profile, there is very limited data on functional outcome in patients with a trans-anal ileal pouch-anal anastomosis surgery (ta-IPAA).

Objective: The objective of this study is to determine if functional outcome following ta-IPAA is the same as or better than postoperative function after tabd-IPAA with UC and IBDu.

Study design: The FUNCTIon trial is a non-inferiority randomized, controlled trial that will involve 3 hospitals across North-America and Europe.

Patient population: All patients with UC and IBDu eligible for pelvic pouch procedure will be randomized to either ta-IPAA or tabd-IPAA. Prior to the start of the study REB will be obtained at all centres and informed consent will be obtained from all patients. The inclusion criteria for the study are: patients between 18 and 60 years old with UC or IBD unclassified (IBDu) eligible for surgery. They will need to speak either English or the primary language of the center they are treated at. The exclusion criteria for the study are: contraindication for laparoscopy, familial adenomatous polyposis (FAP), colorectal cancer, presence of primary sclerosing cholangitis (PSC), a hand-sewn ileo-anal anastomosis, immunomodulating therapy including steroids, pregnancy and lactating, urgent indication.

Intervention: ta-IPAA or tabd-IPAA. Outcomes: Primary outcome is the functional outcome at one year after pelvic pouch surgery. This will be measured using the validated Colorectal Functional Outcome (COREFO) questionnaire. Secondary outcomes are functional outcome at 3 and 6 months, male and female sexual function, perioperative measures and clinical measures.

Sample Size: A sample of 48 (24 per group) is required to detect a between-group non-inferiority margin of 7.05 in COREFO score with a 1-sided α of 0.05 and a power of 80%, allowing for 20% attrition. A participation rate of 50% is anticipated.

Analysis: All continuous variable outcomes will be compared using analysis of covariance. Categorical variable outcomes will be analyzed using repeated measures logistic regression. Proportional outcomes will be analyzed with the chi-square or Fisher's exact test and continuous variables will be analyzed with student's t-test.

Follow-up: Each participant will be followed up at 6 weeks, 3 months, 6 months and 12 months after the intervention to assess functional scores and clinical events. Perioperative events (including postoperative complications) will be assessed during the intervention hospitalization period.