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Indiana Augmentation Cystoplasty (IAC)

The Indiana Augmentation Cystoplasty (IAC) adapts the Indiana pouch principle to augment the native bladder rather than replace it after cystectomy. The detubularized ileocecal segment is anastomosed to a bivalved native bladder, and the plicated ileocecal valve plus tapered terminal ileum provides a continent catheterizable channel — all from a single bowel harvest.[4]

The operation gives a neurogenic-bladder patient simultaneous augmentation and a continent stoma without requiring a separate Mitrofanoff/Monti channel, and without disturbing the ureters.

For the design rules common to every catheterizable conduit see Principles of Continent Catheterizable Channels. Compared techniques: Appendicovesicostomy, Yang-Monti Channel, Tubularized Bladder Flap, Hemi-Kock Continent Stoma.

Lineage and Concept​

The Indiana pouch was developed at Indiana University in 1984 as a modification of Gilchrist's 1950 ileocecal continent reservoir.[1] Gilchrist relied on the native ileocecal valve alone but suffered high incontinence rates because the cecum was not detubularized — high tubular pressures overwhelmed the valve. The Indiana group recognized that full detubularization of the colonic reservoir was essential, and that the ileocecal valve had to be reinforced by plication and ileal tapering to function reliably.[2][1]

Subsequent evolution:[1][2][3][4]

StepModification
1984Original Indiana pouch — cecal reservoir + ileal patch + simple plication of the ileocecal valve.
1991 (Ahlering)Modified Indiana pouch — full antimesenteric detubularization of the colonic segment with folding/transverse closure, reinforced ileocecal plication, simplified transcolonic ureteral reimplantation.
1994 (Rowland)Stapled modifications — absorbable GIA / TA-55 staples for detubularization/closure and efferent-limb tapering.
IAC (Khavari / Boone)Adaptation of the Indiana principle for augmentation of a native bladder, specifically for neurogenic patients.

Surgical Anatomy​

The Indiana ileocecal segment is uniquely suited to a continent reservoir + catheterizable channel because it provides three features in one harvest:[5][1]

  • Large-capacity reservoir from cecum / ascending colon (when detubularized → low-pressure, high-compliance).
  • Natural one-way valve at the ileocecal junction, available to be reinforced.
  • Narrow-caliber efferent limb (terminal ileum) that can be tapered and brought to the skin as a flush stoma.

The standard harvest is 8–12 cm of terminal ileum plus 26–30 cm of right colon (cecum + ascending colon).[3]

Standard Indiana Pouch — Foundational Steps​

The IAC builds on these steps, then diverges at the bladder anastomosis.

1. Bowel isolation and ileocolic re-anastomosis​

Terminal 8–12 cm of ileum and 26–30 cm of right colon isolated on the ileocolic pedicle. Bowel continuity restored with an ileoascending or ileotransverse anastomosis.[3][1]

2. Appendectomy​

Standard; in the modified Indiana, simplified through the colonic wall.[3]

3. Detubularization of the colonic segment​

The defining low-pressure step:[2][3][1]

  • Open the colon along its antimesenteric tenia.
  • Fold and close transversely with running absorbable suture, creating a wide spherical pouch.
  • Original technique used an ileal patch sewn onto the opened cecum to add capacity.
  • Contemporary technique uses absorbable GIA + TA-55 staples for both detubularization and closure.
  • Pouch capacity 400–800 mL at low pressure.

4. Ureteral reimplantation (standard Indiana only)​

In the post-cystectomy Indiana pouch, ureters are reimplanted into the colonic segment with antireflux protection — transcolonic submucosal tunnel (Ahlering modified Indiana), tunneled tenial implants, Le Duc, or Wallace anastomosis. Stricture rates 5–7.2%.[3][2][6][7]

Crucially, the IAC skips this step — the ureters stay in the native bladder.[4]

5. Continence mechanism — plicated ileocecal valve + tapered ileum​

The signature feature of the Indiana family. Continence is synergistic across four contributors:[5]

  • Ileocecal-valve plication. Multiple rows of interrupted or running seromuscular sutures along the terminal ileum at the ileocecal junction narrow the lumen and reinforce the natural valve, creating a high-pressure zone that resists efflux.[2][3]
  • Ileal tapering. Reduces the efferent caliber to facilitate catheterization and increase resistance — by suture plication (folding the wall over itself) or stapled excision (linear GIA along the antimesenteric border). Stapled tapering produced higher mean contraction pressures than plicated (p = 0.054), with similar maxima; both are effective.[8]
  • Ileal peristalsis. Isoperistaltic contractions of the terminal ileum actively resist retrograde flow.[5]
  • Low intraluminal pressure. Detubularized colonic reservoir keeps pressure below the valve threshold even at high volumes.[5]

Video-urodynamics confirm that no single factor is sufficient — continence depends on the synergism of all four.[5]

6. Stoma creation​

The tapered terminal ileum is brought through the abdominal wall as a flush stoma — usually at the umbilicus (cosmesis) or right lower quadrant. The stoma accepts a 14–16 Fr catheter for clean intermittent catheterization.[9]

IAC — Where the Operation Diverges​

The IAC is technically identical to the standard Indiana pouch through bowel isolation and the continence mechanism (plicated ileocecal valve + tapered ileum). It diverges at the bladder anastomosis:[4]

  1. Native bladder is bivalved (opened widely) rather than removed.
  2. The detubularized ileocecal segment is anastomosed to the bivalved bladder with running absorbable suture, augmenting capacity.
  3. Ileocecal valve plication and ileal tapering performed identically to the standard Indiana pouch.
  4. Tapered ileal efferent limb brought to the skin as the catheterizable stoma.
  5. Concurrent procedures (Khavari/Boone series): bladder-neck closure 9%, pubovaginal sling 12%, artificial urinary sphincter 3%, hysterectomy 9%.

Standard Indiana Pouch vs IAC​

FeatureStandard Indiana PouchIAC
Primary indicationPost-cystectomy diversion (bladder cancer)Neurogenic bladder needing augmentation + continent stoma
Native bladderRemoved (cystectomy)Preserved and augmented
ReservoirStand-alone ileocecal pouchNative bladder + ileocecal augmentation patch
Ureteral managementReimplanted into pouchStay in native bladder — no ureteral surgery
Continence mechanismPlicated ileocecal valve + tapered ileumSame
Bladder outletN/AMay be closed, slung, AUS, or left intact
Patient populationPrimarily oncologic adultsPrimarily neurogenic adults

IAC Outcomes — Khavari / Boone n = 34​

The defining series, 1993–2010 follow-up:[4]

  • Mean age 39.8 yr; MS 35%, SCI 41%, spina bifida 26%.
  • Continence 100% at latest follow-up.
  • Mean EBL 461.8 mL.
  • Short-term complications: prolonged ileus 6%, wound infection 3%, transfusion 3%.
  • Long-term complications 44.1%: recurrent UTI 12%, pyelonephritis 3%, pelvic abscess 3%, bladder stones 6%, stomal revision 12%.
  • Stomal revision 12% (4/34).
  • Median follow-up 31 months.

Authors' conclusion: an excellent option providing a low-pressure reservoir with a reliable continence mechanism and easily catheterizable stoma, with few complications or need for reoperation.[4]

Why IAC over Augmentation + Separate Channel​

In a multi-institutional comparison of 61 adults (Redshaw), patients with continent cutaneous ileal cecocystoplasty (IAC concept) needed significantly fewer secondary procedures than those with tunneled channels (appendicovesicostomy / Monti):[11]

  • Secondary procedures 13% vs 50% (OR 6.4, 95% CI 1.8–28).
  • Total secondary procedures 4 vs 27.
  • Stomal leakage 29% vs 43% (NS).

The finding supports the view that the ileocecal-valve mechanism is more durable than the submucosal-tunnel (Mitrofanoff) mechanism in adults for long-term maintenance.

Outcomes of the Standard Indiana Pouch (for reference)​

The post-cystectomy Indiana pouch has a long evidence base supporting the same continence mechanism used in the IAC.

Continence​

  • 97% day-and-night continence at 1 yr (Rowland, n = 69, ≥2 yr follow-up).[2]
  • 99% in robotic-assisted series (Kim, n = 97, median 93 mo).[12]
  • 100% in comparative studies vs Kock and ileal conduit.[13][14]
  • Significantly higher continence than neo-appendico-umbilicostomy at 90 days (p = 0.04).[15]

Long-term durability​

In Polm 2024 (benign indications, very long follow-up), mean revision-free survival was 198 months (>16 years).[16] About a third required revision in the first year, but new-revision incidence dropped substantially after that — described as a durable diversion option for younger patients with benign indications.

Indiana vs Kock (Arai n = 115)​

Mean follow-up 53 mo (Kock), 34 mo (Indiana):[17]

KockIndiana
Surgical revision22.1%10.8%
Stone formation26.5%5.4%
ContinenceSatisfactorySatisfactory
Early complications18.4%17.9%

The Indiana pouch had no reservoir-related early problems, whereas the Kock had nipple-valve malfunctions. Conclusion: comparable function and reoperation rate but lower stone formation.

Complications​

Efferent-limb complications — the principal source of morbidity​

In Holmes (n = 125, mean 41 mo), 58.4% of all complications were efferent-limb related:[6]

  • Incontinence (any leakage) 28.0%
  • Stomal stenosis 15.2%
  • Difficult catheterization 9.6%
  • Pouch stones 10.4%; perioperative leak 4.0%; pouch perforation 3.2%.[6]
  • Hourglass deformity in early cases with incomplete cecal detubularization, requiring repair.[17][18]

Ureteral complications​

  • Ureteroenteric stricture 7.2%.[6]
  • Balloon dilation fails 83% of the time; ureteral reimplantation succeeds in 91%.[7]
  • The IAC sidesteps this entire failure mode because the ureters stay in the native bladder.

Other​

  • Gallstones 25.6% — high rate attributed to disruption of the enterohepatic circulation by ileocecal harvest.[6]
  • Kidney stones 6.4%; small-bowel obstruction 4.8%; parastomal hernia 4.8%.[6]

Reoperation​

  • 52% in long-term Holmes series (mean 41 mo) — but 60% of reoperations were minimally invasive (endoscopic, percutaneous, ESWL).[6]
  • 17% in Rowland (≥2 yr).[2]
  • Burns 2022 (n = 137, 2012–2018): 7.3% early, 8% midterm reoperation.[10]

Complications accumulate over time — short-follow-up series understate the total burden.[6]

Radiation history​

Previously irradiated patients are at significantly higher complication risk. 56% of late complications in the Wilson series occurred in patients who received 3,000–6,500 rad of pelvic radiation; these patients need shorter ureteral tunnels and may benefit from an ileal patch at construction to ensure adequate volume.[7]

Indiana / IAC vs Other Continent Cutaneous Diversions​

FeatureIndiana / IACKock pouchMainz Pouch I
Bowel segmentTerminal ileum + right colonIleum only (~60–80 cm)Cecum + 2 ileal loops
Continence mechanismPlicated ileocecal valve + tapered ileumIntussuscepted nipple valve (×2)Appendix in submucosal tunnel or ileal intussusception
Continence97–100%90–94%91–93%
Surgical revision10.8–17%22.1–38%~15%
Stone formation5.4–12.9%26–44%5.6–10.8%
Technical complexityModerateHigh (nipple valve)Moderate–high
Foreign materialNone (or absorbable staples)Metal staples / Marlex (historical)None or staples
Unique advantageSimple, reliable, low stone rateStand-alone ileal reservoirVersatile; appendix stoma
Unique disadvantageLoss of ileocecal valve → diarrhea riskNipple slippage; stone formationLoss of ileocecal valve

Metabolic Consequences​

Loss of the ileocecal valve​

Indiana / IAC harvest sacrifices the ileocecal valve, with predictable GI consequences:[22]

  • Shortened intestinal transit → diarrhea, malabsorption.
  • Loss of the braking function that normally slows passage of ileal effluent into the colon.
  • Particularly problematic in patients with prior bowel resection or in myelomeningocele patients with already-frequent defecation.

Fisch described a functional reconstruction of the ileocecal valve by embedding ileum into the ascending colon via a submucosal tunnel — mimics the physiological valve and prolongs transit without obstruction.[22]

Vitamin B12 deficiency​

Terminal-ileum harvest puts patients at risk for B12 malabsorption:[23]

  • 67% of Indiana patients were B12 malabsorbers on Schilling test (vs 33% of Kock patients).
  • Mean serum B12 lower in continent reservoirs vs ileal conduit (536 vs 727 pg/mL).
  • Serial determinations show progressive decline in some.
  • No megaloblastic anemia or neurologic symptoms at the time of study, but risk increases with time.
  • Annual serum B12 surveillance is recommended in all continent-reservoir patients.

Hyperchloremic metabolic acidosis​

Urine exposed to colonic mucosa drives chloride absorption and bicarbonate secretion → hyperchloremic acidosis. Common to all bowel-segment continent reservoirs; monitor electrolytes and bicarbonate; supplement when clinically significant.[24]

Decision Algorithm​

Clinical scenarioPreferred techniqueRationale
Post-cystectomy (bladder cancer)Standard Indiana PouchBladder removed; stand-alone reservoir needed.
Neurogenic bladder needing augmentation + continent stomaIACPreserves native bladder; single bowel segment provides both augmentation and channel; no ureteral surgery.
Neurogenic bladder with adequate capacityAppendicovesicostomy or TBFNo augmentation needed; simpler operation.
Prior pelvic radiationIndiana with ileal patch + short ureteral tunnelsRadiation increases complication risk; modifications reduce stricture rate.
Prior ileocecal resectionHemi-Kock or ileocystoplasty + MontiIleocecal segment unavailable.
Concern for diarrhea / malabsorptionConsider ileocecal-valve reconstruction (Fisch) or alternativeLoss of ileocecal valve worsens GI function.

Robotic-Assisted Indiana Pouch​

Successfully performed with robotic assistance after radical cystectomy. In Kim's 16-year series (n = 97, median 93 mo):[12]

  • Continence 99%.
  • Median operative time 8.0 hr; median LOS 8.3 d.
  • 30-day major complications (Clavien III–V) 17.5%; 90-day 22.7%.
  • Most common major complications: abdominal infection and ureteroenteric stricture.
  • Median OS 108 mo; readmission 21.4%.

Continent cutaneous diversion accounts for only 8–10.4% of US radical cystectomies; surgeon training, geography, and socioeconomic factors — not clinical factors — frequently determine whether patients are offered this option.[12]

Quality of Life​

Comparing Indiana pouch vs appendico-umbilicostomy (AU) vs neo-appendico-umbilicostomy (NAU): all groups reported little-to-no disturbance of daily functions and rated overall QoL good-to-excellent on the EORTC QLQ-C30. Indiana had fewer high-grade diversion-related complications than both AU and NAU.[15]

Plicated vs Stapled Efferent Limb​

Carroll and Presti urodynamic comparison (n = 21):[8]

  • Stapled segments had higher mean contraction pressures (p = 0.054).
  • Maximum contraction pressures similar (p = 0.48).
  • Both techniques provide effective continence.
  • Stapled tapering is faster and technically simpler.

See Also​

References​

1. Rowland RG. Present experience with the Indiana pouch. World J Urol. 1996;14(2):92–98. doi:10.1007/BF00182564

2. Rowland RG, Kropp BP. Evolution of the Indiana continent urinary reservoir. J Urol. 1994;152(6 Pt 2):2247–2251. doi:10.1016/s0022-5347(17)31651-8

3. Ahlering TE, Weinberg AC, Razor B. Modified Indiana pouch. J Urol. 1991;145(6):1156–1158. doi:10.1016/s0022-5347(17)38561-0

4. Khavari R, Fletcher SG, Liu J, Boone TB. A modification to augmentation cystoplasty with catheterizable stoma for neurogenic patients: technique and long-term results. Urology. 2012;80(2):460–464. doi:10.1016/j.urology.2012.03.038

5. Juma S, Morales A, Emerson L. The mechanisms of continence in the Indiana pouch: a video-urodynamic study. J Urol. 1990;143(5):973–974. doi:10.1016/s0022-5347(17)40154-6

6. Holmes DG, Thrasher JB, Park GY, Kueker DC, Weigel JW. Long-term complications related to the modified Indiana pouch. Urology. 2002;60(4):603–606. doi:10.1016/s0090-4295(02)01945-3

7. Wilson TG, Moreno JG, Weinberg A, Ahlering TE. Late complications of the modified Indiana pouch. J Urol. 1994;151(2):331–334. doi:10.1016/s0022-5347(17)34940-6

8. Carroll PR, Presti JC. Comparison of plicated and stapled continent ileocecal stoma. Urology. 1992;40(2):107–109. doi:10.1016/0090-4295(92)90504-p

9. Khosla AA, Mendhiratta N, Jatwani K. Urinary diversion after cystectomy for bladder cancer. JAMA Oncol. 2025. doi:10.1001/jamaoncol.2025.3644

10. Burns R, Speir R, Kern SQ, et al. Early and midterm complications of the continent catheterizable Indiana pouch urinary diversion: a 7-year experience. Urology. 2022;167:229–233. doi:10.1016/j.urology.2022.04.016

11. Redshaw JD, Elliott SP, Rosenstein DI, et al. Procedures needed to maintain functionality of adult continent catheterizable channels: a comparison of continent cutaneous ileal cecocystoplasty with tunneled catheterizable channels. J Urol. 2014;192(3):821–826. doi:10.1016/j.juro.2014.03.088

12. Kim AH, Ruel NH, Yamzon J, et al. Indiana pouch continent cutaneous urinary diversion after robotic-assisted radical cystectomy: a 16-year experience. Urology. 2024;183:e325–e327. doi:10.1016/j.urology.2023.10.023

13. Ahlering TE, Weinberg AC, Razor B. A comparative study of the ileal conduit, Kock pouch and modified Indiana pouch. J Urol. 1989;142(5):1193–1196. doi:10.1016/s0022-5347(17)39026-2

14. Santucci RA, Park CH, Mayo ME, Lange PH. Continence and urodynamic parameters of continent urinary reservoirs: comparison of gastric, ileal, ileocolic, right colon, and sigmoid segments. Urology. 1999;54(2):252–257. doi:10.1016/s0090-4295(99)00098-9

15. Cheng KW, Yip W, Shah A, et al. Stoma complications and quality of life in patients with Indiana pouch versus appendico/neo-appendico-umbilicostomy urinary diversions. World J Urol. 2021;39(5):1521–1529. doi:10.1007/s00345-020-03348-z

16. Polm PD, Wyndaele MIA, de Kort LMO. Very long-term follow-up of Indiana pouches proves durability. Neurourol Urodyn. 2024;43(5):1090–1096. doi:10.1002/nau.25344

17. Arai Y, Kawakita M, Terachi T, et al. Long-term followup of the Kock and Indiana pouch procedures. J Urol. 1993;150(1):51–55. doi:10.1016/s0022-5347(17)35394-6

18. Okada Y, Shichiri Y, Terai A, et al. Management of late complications of continent urinary diversion using the Kock pouch and the Indiana pouch procedures. Int J Urol. 1996;3(5):334–339. doi:10.1111/j.1442-2042.1996.tb00549.x

22. Fisch M, Wammack R, Spies F, et al. Ileocecal valve reconstruction during continent urinary diversion. J Urol. 1994;151(4):861–865. doi:10.1016/s0022-5347(17)35107-8

23. Terai A, Okada Y, Shichiri Y, et al. Vitamin B12 deficiency in patients with urinary intestinal diversion. Int J Urol. 1997;4(1):21–25. doi:10.1111/j.1442-2042.1997.tb00133.x

24. Cheng PJ, Myers JB. Augmentation cystoplasty in the patient with neurogenic bladder. World J Urol. 2020;38(12):3035–3046. doi:10.1007/s00345-019-02919-z