Several large series of restorative pouch surgery indicate that a diagnosis of indeterminate colitis is compatible with successful IPAA [21]. The risk of pouch failure is not substantially increased, but a tendency for more complications has been noted in some studies but not others [22]. A group from the Mayo Clinic initially reported a slightly higher failure rate in patients with indeterminate colitis [23]; however, data from the Cleveland Clinic show no differences with respect to functional outcomes or complication rates [24]. The St. Mark’s Hospital experience is that as long as indeterminate colitis does not have features favoring Crohn’s disease, there are no differences in failure rates or functional outcomes [14]. Today, most surgeons would agree that – notwithstanding a slight uncertainty regarding an increased risk of pouch failure –advising patients with indeterminate colitis to consider having IPAA is justified [25]. In terms of risks for developing pouchitis and cancer, there seem to be no major differences compared with ulcerative colitis [26].

Yet a dilemma remains: operating on patients with IBD unclassified does not automatically infer that the pathologist’s report will conclude a diagnosis of indeterminate colitis. The preoperative diagnosis is based on mucosal biopsies, whereas the colectomy specimen provides full-thickness material, and the diagnosis may turn out to be Crohn’s disease. With this in mind, most surgeons recommend a staged procedure, with a colectomy and end ileostomy as the first step. This has the advantage of giving the pathologist a better basis for a definitive diagnosis. In the case of Crohn’s colitis and a patient wishing for a restorative option, the indication for performing an ileorectal anastomosis is stronger, provided the rectum is reasonably healthy. Other alternatives include proctectomy and ileostomy, a continent ileostomy, and expectant, keeping the rectum under surveillance.

In indeterminate colitis the options of an ileorectal anastomosis or an IPAA must be thoroughly discussed with the patient based on several factors, which must be weighed against each other. The pathologist might be inclined toward one or another diagnosis. The rectum itself must be assessed as early as possible after colectomy; waiting too long often results in a diversion (exclusion) proctitis that can be difficult to distinguish from ongoing IBD. Proctitis of some severity, especially with signs of reduced rectal compliance, makes ileorectal anastomosis a less attractive or even impossible alternative. My practice is to recommend treatment with local rectal 5-aminosalicylic acid after colectomy – at least until a definite decision on a next step has been made. In ulcerative colitis, and hence more so in indeterminate colitis, an ileorectal anastomosis is an alternative to proctectomy and a pelvic pouch in select cases. The most obvious is female patients with a strong wish for childbearing; ileorectal anastomosis avoids pelvic dissection to minimize the risk of adhesions affecting the fallopian tubes [27, 28]. Some male patients also absolutely cannot accept even a minute risk of iatrogenic sexual dysfunction. In the elderly, the reduced overall surgical risk involved in an ileorectal anastomosis and the possible worse functional outcome after IPAA might lead patients to choose the rectum-sparing alternative.