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Right Colon Pouch — Mainz I, Miami, Florida, and Right-Colon Orthotopic Variants

The right colon pouch is an umbrella term encompassing several urinary diversion techniques — both continent cutaneous and orthotopic neobladder — that use the right colon (cecum and ascending colon), with or without terminal ileum, to construct a urinary reservoir. The most prominent variants include the Mainz pouch I, Miami pouch, Florida pouch, the Indiana pouch (covered separately), and right-colonic orthotopic neobladders (D'Orazio, Le Bag, Mainz orthotopic).[1][2][3][4][5][6]

Why the Right Colon?​

The right colon offers several anatomical and physiological advantages for reservoir construction:[1][4][5][7]

  • Large caliber and distensibility — facilitates high-capacity, low-pressure reservoir when detubularized
  • Ileocecal valve — natural continence mechanism that can be reinforced for catheterizable continent stomas (Indiana, Florida, Miami)
  • Appendix — usable as a catheterizable efferent limb (Mainz I appendix-stoma modification, appendico-umbilicostomy)[8][9]
  • Teniae coli — allow submucosal-tunnel ureteral reimplantation for antireflux protection[5][10]
  • Proximity to ureters — particularly the right ureter
  • Haustral contractions — in partially detubularized orthotopic designs, intact haustra can assist with voiding[1]

Continent Cutaneous Variants​

Mainz pouch I (mixed augmentation ileum and cecum)​

Developed at Mainz, Germany in 1983 (Thüroff / Alken / Hohenfellner) — the largest reported series of ileocecal continent cutaneous diversions (> 800 patients).[4][5][11]

Construction. 10–15 cm of cecum/ascending colon + two terminal ileal loops (10–15 cm each), all detubularized and reconfigured into a spheroidal reservoir. Continence mechanism: intussuscepted ileal nipple or submucosally embedded in-situ appendix. Ureters reimplanted via submucosal or serosa-lined extramural tunnel.[4][5][10]

Outcomes (n > 800, mean 7.6 yr):[11]

  • Overall continence: 92.8% (day and night)
  • Stomal stenosis — 23.5% (appendix stoma) vs 15.3% (ileal nipple)
  • Pouch calculi — 10.8% (ileal nipple) vs 5.6% (appendix stoma)
  • Uretero-intestinal stricture — 6.5% submucosal tunnel vs 5.0% extramural tunnel[10]
  • Renal function — Cr ≤ 1.6 mg/dL in 97–98%

Pediatric (Stein 2005, n=70, median 8.7 yr):[12] upper tracts stable / improved in 95.8% of renal units; continence 97%; stoma stenosis requiring revision 23%; pouch calculi 15%.

Miami pouch​

University of Miami modification using the terminal 15 cm of ileum + right colon.[13][6][14]

Construction. Right colon detubularized into reservoir. Continence by tapering distal ileum over a 14 Fr catheter + circumferential pursestring reinforcement of ileocecal valve. Ureters anastomosed directly (non-tunneled) to the pouch.[6][14]

SeriesnFUContinenceNotes
Bloch 1992 (original)757–69 mo98.6%Early complications 26%, late 23%, perioperative mortality 6.7%
Salom 2004 (15-yr)9015 yr93%UTI 40%, ureteral stricture 20%, difficult catheterization 18%, perioperative death 11%
Baboudjian 2021 (contemporary)1539 mo87% (100% day, 87% night)Clavien III 13.3%; no stomal stenosis
Pattou 2022 (vs Mitrofanoff)145.4 yr79%Stomal stenosis 7% vs 47% Mitrofanoff (p = 0.02)

The Miami pouch is particularly favored in gynecologic oncology for continent diversion during pelvic exenteration — 91% of the U Miami series had prior radiation; despite this high-risk population, continence remained 93% and most complications were managed conservatively.[14]

Florida pouch​

University of Florida — same concept as the Indiana pouch (detubularized right-colonic reservoir + tapered ileal efferent reinforced at the ileocecal valve).[3][15]

Long-term (Webster 2003, n=74, mean 133 mo):[3]

  • Continence 93.3%; stomal stenosis 4%; reservoir stones 5.4%
  • Ureteral obstruction 6.3% primary vs 28.4% in irradiated ureters (p = 0.02)
  • Severe acidosis 5.5%, low B12 4%, renal failure 2.7%
  • Conversions from another diversion had significantly more metabolic derangements: 58% vs 6.4% (p = 0.0001)

Right colon pouch with appendico-umbilicostomy (AU) / neo-appendico-umbilicostomy (NAU)​

Variants using the native appendix (AU) or a tubularized ileal segment (NAU) as the catheterizable efferent limb, brought to the umbilicus for maximal cosmetic concealment.[16][8][9]

Appendix-stoma advantages:[8] closure pressure > 80 cmH₂O; cosmetically superior (umbilical); simple construction.

IP vs AU vs NAU comparison (Cheng 2021):[16] Indiana pouch had fewer high-grade diversion-related complications than AU; QoL good–excellent in the majority.

Turin pouch (right colon + novel efferent channel)[17]​

Muto 2021, n = 38, median 52 mo: 24-hour continence 89%, stomal stenosis 10.5% (lower than literature average ~ 19.5%), catheterization difficulty 18.4%; reconstructive time only 61 min within median 201 min total OR.

Right Colon Pouch as Orthotopic Neobladder​

D'Orazio right-colonic neobladder[1]​

Detubularized remodeled right colon + intact cecal segment with a unique voiding mechanism.

  • Detubularized portion creates low-pressure reservoir (> 600 mL capacity)
  • Intact cecal segment generates mass contractions > 100 cmH₂O that actively propel urine toward urethra — unlike ileal neobladders (which rely solely on Valsalva)
  • Haustral contractions direct urine from intact segment toward detubularized segment for storage

Outcomes (n=38, 11 yr):

  • Daytime continence 100% (37/38 immediate; 1 at 30 d)
  • Nighttime continence 92% (total and immediate)
  • Maximum flow rate > 26 mL/sec (substantially higher than ileal neobladders)
  • CIC required in 1 patient (2.6%)
  • Continence immediate upon catheter removal in nearly all patients

Le Bag ileocolonic neobladder​

Light & Engelman — ~ 20 cm each of detubularized ileum + cecum.[18][19][20]

Outcomes (n=38):[18]

  • Daytime continence 91%; nighttime 80% completely dry / mild incontinence
  • Mild hyperchloremic acidosis in most (HCO₃⁻ 28 → 24 mmol/L); correlated with pouch length (r = 0.58, p = 0.0002)
  • Stapled construction feasible without increasing complications

B-Bladder modification — Le Bag with a Studer-like ileal chimney for ureteral anastomosis: recurrent UTI 17%, uretero-neobladder stricture 3%.[20]

Ileocecal (Mainz) orthotopic neobladder[4][21]​

Mainz I configured as orthotopic by anastomosing reservoir to membranous urethra. Bedük / Abol-Enein ileocecal-vs-ileal neobladder comparison:

ParameterIleocecal (Mainz)Ilealp
Capacity426 ± 34 mL442 ± 27 mLNS
Max flow rate19.6 ± 3.7 mL/s16 ± 6.1 mL/sNS
Residual volume37 ± 8.2 mL45 ± 7.1 mLNS
Daytime incontinence5.3%5.5%NS
Nighttime incontinence21%8.4%—
Ureteral stricture10.5%5.7%—
Pyelonephritis15.8%13.8%—

Urodynamic parameters comparable, with a trend toward higher nighttime incontinence with the ileocecal configuration.[21]

Right Colon vs Ileal Neobladder​

Cochrane 2012 + comparative studies:[22][7][21]

  • Daytime continence — no significant difference between ileocecal and ileal
  • Nighttime continence — one trial favored ileal over ileocolonic Le Bag (RR 0.35; 95% CI 0.15–0.79); a non-refluxing ileocecal trial showed no difference
  • Urodynamics — comparable capacity, flow, residual
  • Metabolic acidosis — both cause hyperchloremic acidosis; one trial reported higher rate with ileal
  • Upper-tract dilation — potentially lower with ileocecal non-refluxing techniques
  • Continent-cutaneous stomal continence — right-colon pouches with ileocecal valve achieve near-100% continence — the highest of any reservoir type[7]

Metabolic & Renal Function​

Shared across all right-colon-pouch variants:[23][24][25][26]

  • Hyperchloremic metabolic acidosis — present in most; 37% require chronic alkali at > 5 yr[23]
  • Vitamin B12 deficiency — supplementation recommended in 32% of ileocecal-pouch patients (clinical megaloblastic anemia / funicular myelosis not observed)[23][26]
  • Bone health — no clinical osteoporosis at > 5 yr with systematic alkali[23]
  • Diarrhea — loss of ileocecal valve causes increased stool frequency (53%), softer consistency (60%), diarrhea (62%) vs IC patients[27]
  • Urolithiasis — pouch stones 5–15%; increased calcium / phosphate excretion[3][11]

For pharmacologic management see Vitamin B12 supplementation, Urinary acidifiers & alkalinizers, and Mucus management.

Renal function — Pyrgidis 2022 IC vs ileal neobladder vs Mainz I: no significant differences in eGFR decline. Independent predictors: preoperative eGFR, age, tumor stage, septicemia.[28]

Complication Summary — Right-Colon-Pouch Variants​

ComplicationMainz IMiamiFloridaIndianaRight Colon (general)
Overall continence92.8%79–98.6%93.3%94–100%89–100%
Stomal stenosis15–23.5%7%4%15.2%10.5–23%
Pouch stones5.6–10.8%—5.4%10.4%—
Ureteral stricture5–6.5%20%6.3–28.4%7.2%—
90-d high-grade complications—13.3%—17.5%22%
Cumulative reoperation———52–67%32–53%
Metabolic acidosis37% need alkali—5.5% severe——
B12 deficiency32% need supplementation—4%15%—

Risk factors for complications[2][3]​

  • Diabetes — increases postoperative complications and reoperation
  • High BMI / prior abdominal surgery — increases readmission
  • Prior pelvic radiation — dramatically increases ureteral stricture (28.4% vs 6.3%, p = 0.02)
  • Conversion from another diversion — significantly more metabolic derangements (58% vs 6.4%, p = 0.0001)

Bowel Function After Right-Colon Pouch​

Loss of the ileocecal valve has significant GI consequences. Frees 2017 matched-pair analysis Mainz I vs IC:[27]

  • Stool frequency increased — 53% vs 31%
  • Softer stool consistency — 60% vs 13%
  • Diarrhea — 62% vs 20%
  • Constipation decreased — 4% vs 22%
  • Stool incontinence — no difference (p = 0.481)
  • Postoperative QoL — significantly impaired in Mainz I group (51% vs 29%, p = 0.024)

These findings emphasize the importance of preoperative counseling about bowel-habit changes when using ileocecal segments.

Long-Term Surveillance​

Lifelong monitoring for all right-colon-pouch patients:[3][11][23][10][25]

  • Renal function — eGFR; nuclear GFR if creatinine unreliable
  • Metabolic — blood gases, bicarbonate, chloride, B12 annually; alkali supplementation as needed
  • Upper-tract imaging — ultrasound or CT for hydronephrosis, stones, ureteral stricture
  • Pouch assessment — pouchography, stones, integrity
  • Stoma evaluation — stenosis, continence, catheterization difficulty
  • Bowel function — diarrhea, malabsorption, nutritional deficiencies
  • Cancer surveillance — per primary-disease protocol; secondary malignancy in bowel segments exposed to urine (rare, typically > 10 yr)
  • Bone density — consider in long-term alkali / chronic acidosis

See Also​

References​

1. D'Orazio OR, Lambert OL, Vallati JC, et al. "Total and immediate daytime and nighttime continence with a right-colonic neobladder — what makes it possible? An 11-year followup." J Urol. 2005;174(5):1882–1886. doi:10.1097/01.ju.0000177078.38975.58

2. Myers JB, Martin C, Cheng PJ, Zhang C, Presson AP. "Outcomes of right colon continent urinary pouch using standardized reporting methods." Neurourol Urodyn. 2019;38(5):1290–1297. doi:10.1002/nau.23951

3. Webster C, Bukkapatnam R, Seigne JD, et al. "Continent colonic urinary reservoir (Florida pouch): long-term surgical complications (> 11 years)." J Urol. 2003;169(1):174–176. doi:10.1016/S0022-5347(05)64061-X

4. Thüroff JW, Alken P, Riedmiller H, Jacobi GH, Hohenfellner R. "100 cases of Mainz pouch: continuing experience and evolution." J Urol. 1988;140(2):283–288. doi:10.1016/s0022-5347(17)41584-9

5. Thüroff JW, Alken P, Riedmiller H, et al. "The Mainz pouch (mixed augmentation ileum and cecum) for bladder augmentation and continent diversion." J Urol. 1986;136(1):17–26. doi:10.1016/s0022-5347(17)44714-8

6. Bloch WE, Bejany DE, Penalver MA, Politano VA. "Complications of the Miami pouch." J Urol. 1992;147(4):1017–1019. doi:10.1016/s0022-5347(17)37451-7

7. 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

8. Riedmiller H, Bürger R, Müller S, Thüroff J, Hohenfellner R. "Continent appendix stoma: a modification of the Mainz pouch technique." J Urol. 1990;143(6):1115–1117. doi:10.1016/s0022-5347(17)40200-x

9. Nurmi M, Rajala P, Laato M. "Clinical experience with the detubularized ileocecal reservoir and continent appendico-umbilical stoma in urinary diversion." Eur Urol. 1997;31(2):169–172. doi:10.1159/000474444

10. Wiesner C, Pahernik S, Stein R, et al. "Long-term follow-up of submucosal tunnel and serosa-lined extramural tunnel ureter implantation in ileocaecal continent cutaneous urinary diversion (Mainz pouch I)." BJU Int. 2007;100(3):633–637. doi:10.1111/j.1464-410X.2007.06991.x

11. Wiesner C, Bonfig R, Stein R, et al. "Continent cutaneous urinary diversion: long-term follow-up of more than 800 patients with ileocecal reservoirs." World J Urol. 2006;24(3):315–318. doi:10.1007/s00345-006-0078-y

12. Stein R, Wiesner C, Beetz R, et al. "Urinary diversion in children and adolescents with neurogenic bladder: the Mainz experience. Part II: continent cutaneous diversion using the Mainz pouch I." Pediatr Nephrol. 2005;20(7):926–931. doi:10.1007/s00467-005-1848-2

13. Baboudjian M, Gondran-Tellier B, Michel F, et al. "Miami pouch: a simple technique for efficient continent cutaneous urinary diversion." Urology. 2021;152:178–183. doi:10.1016/j.urology.2021.02.004

14. Salom EM, Mendez LE, Schey D, et al. "Continent ileocolonic urinary reservoir (Miami pouch): the University of Miami experience over 15 years." Am J Obstet Gynecol. 2004;190(4):994–1003. doi:10.1016/j.ajog.2004.01.023

15. Pow-Sang JM, Helal M, Figueroa E, et al. "Conversion from external appliance wearing or internal urinary diversion to a continent urinary reservoir (Florida pouch I and II): surgical technique, indications and complications." J Urol. 1992;147(2):356–360. doi:10.1016/s0022-5347(17)37236-1

16. 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

17. Muto G, Giacobbe A, Collura D, et al. "A right colon pouch with a novel efferent channel concept: long-term results of the Turin pouch." World J Urol. 2021;39(6):1935–1940. doi:10.1007/s00345-020-03412-8

18. Kolettis PN, Klein EA, Novick AC, Winters JC, Appell RA. "The Le Bag orthotopic urinary diversion." J Urol. 1996;156(3):926–930.

19. Vara AR, Shanberg AM, Sawyer DE, Tansey LA, Martin DC. "Modification of Le Bag ileocolonic pouch with improved results: review of 17 cases." Urology. 1992;40(3):221–226. doi:10.1016/0090-4295(92)90478-f

20. Baniel J, Tal R. "The 'B-bladder' — an ileocolonic neobladder with a chimney: surgical technique and long-term results." Eur Urol. 2004;45(6):794–798. doi:10.1016/j.eururo.2004.01.013

21. Bedük Y, Türkölmez K, Baltaci S, Göğüş C. "Comparison of clinical and urodynamic outcome in orthotopic ileocaecal and ileal neobladder." Eur Urol. 2003;43(3):258–262. doi:10.1016/s0302-2838(03)00042-3

22. Cody JD, Nabi G, Dublin N, et al. "Urinary diversion and bladder reconstruction/replacement using intestinal segments for intractable incontinence or following cystectomy." Cochrane Database Syst Rev. 2012;(2):CD003306. doi:10.1002/14651858.CD003306.pub2

23. Pfitzenmaier J, Lotz J, Faldum A, et al. "Metabolic evaluation of 94 patients 5 to 16 years after ileocecal pouch (Mainz pouch 1) continent urinary diversion." J Urol. 2003;170(5):1884–1887. doi:10.1097/01.ju.0000091900.57347.ee

24. Roth JD, Koch MO. "Metabolic and nutritional consequences of urinary diversion using intestinal segments to reconstruct the urinary tract." Urol Clin North Am. 2018;45(1):19–24. doi:10.1016/j.ucl.2017.09.007

25. Cruz DN, Huot SJ. "Metabolic complications of urinary diversions: an overview." Am J Med. 1997;102(5):477–484. doi:10.1016/S0002-9343(97)00020-X

26. Davidsson T, Lindergård B, Månsson W. "Long-term metabolic and nutritional effects of urinary diversion." Urology. 1995;46(6):804–809. doi:10.1016/s0090-4295(99)80348-3

27. Frees S, Schenk AC, Rubenwolf P, et al. "Bowel function in patients with urinary diversion: a gender-matched comparison of continent urinary diversion with the ileocecal pouch and ileal conduit." World J Urol. 2017;35(6):913–919. doi:10.1007/s00345-016-1949-5

28. Pyrgidis N, Sokolakis I, Haltmair G, Hatzichristodoulou G. "The effect of urinary diversion on renal function after cystectomy for bladder cancer: comparison between ileal conduit, orthotopic ileal neobladder, and heterotopic ileocecal pouch." World J Urol. 2022;40(12):3091–3097. doi:10.1007/s00345-022-04211-z