The Indiana pouch (IP) is an ileocolonic, heterotopic, continent, urinary diversion. Since it was introduced in the 1980s, it is viewed as an option for patients undergoing radical cystectomy for bladder carcinoma. Several studies have described long-term follow-up, however none longer than 5 years. (1) IPs can also be created in patients with a non-oncological indication for a urinary diversion. These patients generally receive an IP at younger age and tend to have a longer survival. Therefore, very long-term outcome and complication data (>5 years) are relevant and of interest.

All patients with an IP under surveillance at our functional urology academic tertiary referral center between 2015 and 2022 were identified for this retrospective cohort study. At our institution patients with IPs are invited for yearly physical follow-up. This consultation is standardized and consists of a medical interview with questions focusing on identifying IP-related functions and potential problems such as the incidence of urinary tract infections, catheterization (frequencies/ volumes), leakage and problems with catheterization. Additionally, laboratory testing (electrolytes and estimated Glomerular Filtration Rate (eGFR), vitamin B12, and folic acid) and an ultrasound (IP and upper urinary tract) are conducted. Pouchoscopy is performed every other year for IPs older than 10 years, or on indication. For this study all data mentioned above were retrospectively collected from patients’ clinical records as well as data concerning medical history, indication for IP creation, age at IP creation and gender. Follow-up was defined as time from pouch creation to either death, revision to other deviation, lost to follow-up or most recent consultation. Incidence of complications (stomal stenosis, ureter-pouch stenosis, pouch calculi, stomal leakage, pouch perforation and parastomal herniation) were collected and both, time to-, and type of surgical revision were registered. Recurrent urinary infections were defined as >4 /year.

In total, 35 patients were included (24 female). Median age at pouch creation was 38 years (range 5-62) and median follow-up was 230 months (range 6-424). 30 patients had a non-oncological indication for urinary diversion. 22 patients (63%) underwent surgical revision during follow-up. The reason for surgical revision is depicted in Table 1. The total number of surgical revisions was 46. The estimated median revision free survival was 193 months (95%-CI 141-245). Pouch survival until first surgical revision is shown in figure 1. Median renal function by means of eGFR was 79 ml/min at final follow-up. Recurrent urinary tract infections were seen in 13 patients (37%) and for three patients these infections caused so much bother that they opted for conversion to an ileal conduit. Vitamin B12, folic acid or bicarbonate suppletion was required in 11 patients (31%). Six patients had treatment for upper tract calculi during follow-up; this was not interpreted as a pouch complication. During follow-up no pouch malignancies were discovered.

We present a large cohort of individuals with an IP with careful long-term follow-up of almost twenty years. The rate of surgical revision was 63% but it should be recognized that the estimated revision free survival is 193 months, implicating that a significant group of patients have a long lasting well-functioning continent urinary diversion. In these patients renal function was well preserved and no malignancies occurred. 
Comparison to other literature is difficult because complication rates are highly dependent on follow-up duration. The largest cohort of individuals with IPs described in literature is 125 with a mean follow-up of 41.1 months and a reoperation rate of 52%. (2) In our study, reoperation rate was 23% at 41 months.
In our series and in literature, stomal stenosis or leakage are the most frequent reasons for surgical revision, counting for 18 of 46 reoperations. In preoperative counseling it is important to note that these complications of the catheterizable stoma only apply to an IP and are not an issue for ileal conduits in long-term follow-up. 
Ureter-pouch stenosis is the other most frequent reason for reoperation, either endoscopically or by open surgery. In our study 14% of the patients developed ureter-pouch stenosis requiring open revision. This incidence is comparable with ureter-conduit stenosis in long-term follow-up of ileal conduits.[3] Minimally invasive management of ureter-pouch stenosis, however, both with antegrade or retrograde stenting, is more difficult in IP compared to ileal conduit. The fact that ureter-pouch stenosis occurred in some patients after 20 years, eventually developing insidiously and asymptomatic, illustrates the need for lifelong follow up in these patients.
Neither in our series nor in literature, any pouch malignancy was diagnosed. It is doubtful whether periodic endoscopy of IP is necessary for the purpose of detecting pouch malignancies.

In our cohort of patients with Indiana pouches, on the very long-term, over half required a form of surgical revision. However, a median revision free survival of 193 months and very long-term preservation of renal function, render the Indiana pouch a very durable option for urinary diversion. These outcomes should be used in counseling patients who opt for a urinary diversion.

Meyers JB, et al. Perioperative and long-term surgical complications for the Indiana pouch and similar continent catheterizable urinary diversions. Curr Opin Urol 2016, 26:376–382.
Holmes DG, et al. Long-term complications related to the modified Indiana pouch. Urology 2002; 60:603–606.
Madersbacher S, Schmidt J, Eberle JM, et al. Long-term outcome of ileal conduit diversion. J Urol 2003;169:985–90.