Is diverting loop ileostomy necessary for completion proctectomy with ileal pouch-anal anastomosis? A multicenter randomized trial of the GETAID Chirurgie group (IDEAL trial): rationale and design (NCT03872271).

Background: There is no quality evidence of the benefit of defunctioning ileostomy (DI) in ileal pouch-anal anastomoses (IPAAs) performed for inflammatory bowel disease (IBD), but most surgical teams currently resort to DI. In the case of a staged procedure with subtotal colectomy first, completion proctectomy with IPAA is performed for healthy patients, namely, after nutritional support, inflammation reduction and immunosuppressive agent weaning. Therefore, the aim of this trial is to assess the need for systematic DI after completion proctectomy and IPAA for IBD.

Methods/design: This is a multicenter randomized open trial comparing completion proctectomy and IPAA without (experimental) or with (control) DI in patients presenting with ulcerative colitis or indeterminate colitis. Crohn's disease patients will not be included. The design is a superiority trial. The main objective is to compare the 6-month global postoperative morbidity, encompassing both surgical and medical complications, between the two groups. The morbidity of DI closure will be included, as appropriate. The sample size calculation is based on the hypothesis that the overall 6-month morbidity rate is 30% in the case of no stoma creation (i.e., experimental group) vs. 55% otherwise (control group). With the alpha risk and power are fixed to 0.05 and 0.80, respectively, and considering a dropout rate of 10%, the objective is set to 194 patients. The secondary objectives are to compare both strategies in terms of morbi-mortality at 6 months and functional results as well as quality of life at 12 months, namely, the 6-month major morbidity and unplanned reoperation rates, 6-month anastomotic leakage rate, 6-month mortality, length of hospital stay, 6-month unplanned readmission rate, quality of life assessed 3 and 12 months from continuity restoration (i.e., either IPAA or stoma closure), functional results assessed 3 and 12 months from continuity restoration, 12-month pouch results, 12-month cost-utility analysis, and 12-month global morbidity.

Discussion: The IDEAL trial is a nationwide multicenter study that will help choose the optimal strategy between DI and no ileostomy in completion proctectomy with IPAA for IBD.

Trial Registration: ClinicalTrial.gov: NCT03872271, date of registration March 13th, 2019.