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Ureterosigmoidostomy and Mainz Pouch II (Sigma-Rectum Pouch)

Ureterosigmoidostomy (USS) is the oldest form of continent urinary diversion, first performed by Simon in 1852. Both ureters are implanted directly into the sigmoid colon or rectum, urine drains into the bowel and mixes with feces, and the anal sphincter complex provides continence — eliminating the need for any external appliance, stoma, or catheterization.[1][2][3] Once the most common urinary diversion worldwide, classical USS has been largely supplanted by ileal conduits and orthotopic neobladders due to metabolic complications, ascending pyelonephritis, and a markedly elevated risk of colorectal adenocarcinoma. Interest has revived in its modified low-pressure forms — particularly the Mainz Pouch II (sigma-rectum pouch) — because of the simplicity, speed, and minimally-invasive applicability.[1][4][5]

Historical Evolution​

YearMilestone
1852Simon — first ureterosigmoidostomy for bladder exstrophy[2]
1911Coffey — first antireflux technique (mucosal tunnel)[2]
1950sLeadbetter — submucosal tunnel antireflux technique becomes standard[2][8]
1970sGoodwin — transcolonic (open sigmoid) technique with long submucosal tunnel[2]
1980–90sUSS supplanted by ileal conduits and continent cutaneous diversions
1993Fisch & Hohenfellner — Mainz Pouch II (detubularized rectosigmoid)[10]
1997Abol-Enein & Ghoneim — double-folded rectosigmoid bladder with serous-lined extramural antireflux[11]

Surgical Techniques​

Classical ureterosigmoidostomy​

TechniqueAntireflux mechanismNotes
CoffeyNone — ureter through stab wound, sutured to mucosaHistorical
LeadbetterLong submucosal tunnel (3–4 cm)Most widely adopted classical technique[2]
Goodwin transcolonicLong submucosal tunnel from inside the open bowelDirect mucosal-to-mucosal anastomosis under vision[2]
Goodwin "cuff" / "flap"Mucosal cuffExtraperitoneal modification[9]

Key technical principles (all techniques):[2]

  • Long submucosal tunnel (≥ 3 cm)
  • Mandatory preoperative bowel preparation
  • Spatulated ureter for wide anastomosis
  • Ureteral stenting 7–10 d postoperatively
  • Frequent rectal emptying every 2–3 hr postoperatively
  • Lifelong low-chloride diet + sodium / potassium citrate supplementation

Mainz Pouch II (sigma-rectum pouch) — modern standard​

Fisch / Wammack / Hohenfellner 1993.[10][5][12][13][14]

Technique:

  1. Identify rectosigmoid junction; select 15–20 cm segment
  2. Open along antimesenteric border (detubularization)
  3. Suture opened edges side-to-side into a low-pressure spheroidal reservoir
  4. Fix pouch to sacral promontory to prevent ureteral kinking
  5. Reimplant ureters via submucosal tunnel or serous-lined extramural tunnel
  6. Bowel continuity maintained — no colostomy required

Key advantages over classical USS:[5][10][14]

  • Detubularization eliminates high-pressure contractions — basal 24 cmH₂O, peak 35 cmH₂O (vs > 60 cmH₂O in intact sigmoid)
  • Improved continence (eliminates urgency / frequency)
  • Better upper-tract protection
  • Reduced metabolic disturbance (less mucosal contact area)
  • Sacral fixation reduces ureteral kinking

Double-folded rectosigmoid bladder (Abol-Enein / Ghoneim 1997)​

S-shaped double-folded reservoir with extramural serous-lined antireflux technique.[11]

Outcomes (n = 57 evaluable, mean 19 mo): 100% daytime continence (2–4 voids/day); 4 children with nocturnal enuresis (responded to imipramine); upper-tract function maintained / improved in 95%; no clinical acidosis (all on prophylactic alkalization).

Detubularized isolated ureterosigmoidostomy (Atta 1996)​

Separates urine from feces — detubularized sigmoid pouch drains into the rectum while fecal continuity is maintained through the left colon. Patients pass clear urine 3–6×/day and solid feces once daily separately. Potentially reduces carcinogenesis risk by limiting urine-feces admixture.[15]

Indications​

USS / Mainz II (with strong preference for the modified forms) is considered in:[1][16][17][13]

  • Patients desiring continent diversion who are not neobladder / continent-cutaneous candidates
  • Bladder exstrophy — historically the most common indication, particularly in children[18][19][20]
  • Bladder cancer requiring radical cystectomy in selected patients
  • Neurogenic bladder with intact anal sphincter
  • Functional urology — intractable urinary incontinence with competent anal sphincter
  • Resource-limited settings — quick, simple, no specialized equipment or appliances
  • Minimally invasive surgery — anastomosis adapts to laparoscopic / robotic approaches[1][21]

Prerequisites[1][2][17]​

  • Competent anal sphincter (mandatory — preoperative rectal manometry or water-holding test)
  • Adequate renal function
  • No IBD
  • No prior pelvic radiation to rectosigmoid (relative)
  • No strong family history of colorectal cancer
  • Patient willingness to accept lifelong colonoscopic surveillance

Contraindications[1][2][17][22]​

AbsoluteRelative
Fecal incontinence / poor anal sphincter tonePrior pelvic radiation to rectosigmoid
Inflammatory bowel diseaseStrong family history of CRC
Severely impaired renal functionAdvanced age with limited life expectancy
Pre-existing colorectal neoplasiaShort ureters (inadequate length for tunnel)
Hepatic dysfunction

Continence Outcomes​

SeriesTechniquenFUDaytimeNighttime
Mayo Clinic (Tollefson)Classical USS5115.7 yr94%94%
BissadaClassical USS6341 mo~ 92%—
Koo (exstrophy)Classical USS2717 yr92%58%
D'elia 2004Mainz Pouch II (10-yr)10246 mo97%95%
Hadzi-DjokicMainz Pouch II22021 mo99%99%
Fisch (original)Mainz Pouch II7310.6 yr94.5%98.6%
ObekMainz Pouch II5031 mo98%98%
GerharzMainz Pouch II34—100%97%
Abol-EneinDouble-folded rectosigmoid5719 mo100%93% (children)
Bastian (QoL cohort)Mainz Pouch II4124 mo100%~ 97%

The detubularized techniques achieve significantly better continence than classical USS by eliminating high-pressure sigmoid contractions that cause urgency and frequency.[5][10]

Complications​

Early (≤ 30 days)[21][13][23]​

  • Classical USS: 12% early complication rate
  • Mainz Pouch II: 3.3–10.9%
  • Perioperative mortality 0% in modern series; historically 3.2% in classical USS

Late​

ComplicationClassical USSMainz Pouch II
Anastomotic stricture22%5–7.2%
Recurrent pyelonephritis16%6–8%
Hydronephrosis23% of renal units5–6.3%
Urolithiasis10%—
Chronic renal insufficiency6%Rare
Severe metabolic acidosis4%6% (hospitalization)
Need for alkali supplementationMost patients52–69%
Reoperation rate37%—
Colorectal neoplasia2–29%Theoretical risk (see below)

The Mainz Pouch II achieves substantially lower complication rates than classical USS, particularly for anastomotic stricture and upper-tract deterioration, due to the low-pressure reservoir and improved ureteral implantation techniques.[12][13][14]

Metabolic Consequences​

The most clinically significant non-neoplastic complication. Colonic mucosa absorbs NH₄Cl and H⁺ from urine while secreting HCO₃⁻ into the lumen — producing hyperchloremic (non-anion-gap) metabolic acidosis:[27][28][29]

  • Acidosis incidence 52–86%; 69% of Mainz II patients require oral alkalizing drugs[12][13][29]
  • Severity correlates with duration of urine contact, surface area exposed, renal function, and frequency of rectal emptying
  • Classical USS produces significantly more severe acidosis (pH 7.29 ± 0.07) than rectosigmoid bladder (pH 7.34 ± 0.04, p < 0.001)[29]
  • Metabolic crises typically coincide with acute pyelonephritis and renal deterioration[27]
  • Hypokalemia — renal compensation for acidosis + colonic K⁺ secretion; can be life-threatening; 6% of Mainz II patients required hospitalization for severe acidosis + hypokalemia[23]
  • Hyperammonemia — rare but potentially fatal; from urinary retention and excessive ammonium absorption[20]

Management:[2][27]

  • Lifelong low-chloride diet + sodium / potassium citrate
  • Frequent rectal emptying to minimize urine contact time
  • Regular monitoring of serum electrolytes, blood gases, renal function
  • Pre-existing renal impairment is a contraindication to USS

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

Colorectal Malignancy — the Defining Concern​

The risk of secondary colorectal adenocarcinoma at the ureterocolonic anastomosis is the most feared long-term complication and the primary reason classical USS fell out of favor.[25][18][6][7][26][8]

Incidence and risk​

  • Overall incidence 2–15%[7]
  • Kälble — 8.5–10.5× increased risk vs general population (mean FU 14.6 yr)[25]
  • Leadbetter — 500× increased risk; ~ 5% lifetime risk[8]
  • Pettersson half-century FU of childhood USS — 42× increased risk vs general Swedish population; 7 of 24 patients (29%) developed invasive colorectal adenocarcinoma; 5 died from it[18]
  • Cipolla — 100–550× increased risk[6]
  • Zabbo — 11% of patients surviving ≥ 15 yr developed colon cancer[19]

Latency​

  • Mean 20–38 yr from USS to cancer diagnosis (range 6–55 yr)[18][7][8]
  • Latency shorter in patients > 40 yr at the time of USS[8]
  • Cancer risk persists after re-diversion — 3 of 7 cancers in the Pettersson series were diagnosed 1, 21, and 25 years after conversion[18]

Pathogenesis[25][6][7]​

  • Nitrosamine hypothesis — bacteria at the ureterocolonic junction reduce nitrate to nitrite, which combines with endogenous amines to form N-nitrosamines; Kälble demonstrated increased nitrite / N-nitrosamine excretion[25]
  • Reactive oxygen species — neutrophils at the healing anastomosis produce DNA-damaging radicals
  • Adenoma-carcinoma sequence at the anastomosis — tubulovillous adenomas / mixed transitional-cell adenomas as precursors[6][7]
  • Tumors almost exclusively at / near the ureterocolonic anastomosis[26]
  • 6 of 7 invasive cancers in Pettersson were poorly differentiated — aggressive biology[18]

Mandatory colonoscopic surveillance[7][26][8][30][31]​

  • Annual colonoscopy beginning no later than 5–6 yr after USS (some advocate immediately)
  • Surveillance must continue after re-diversion — risk persists at the former anastomotic site
  • Sigmoidoscopy adequate for routine screening of the rectosigmoid risk zone; full colonoscopy preferred
  • Benign polyps removed by snare polypectomy
  • If malignancy found — excise colonic segment with ureteric implants + lymphadenectomy + bowel continuity restoration + conversion to ileal conduit
  • Patients noncompliant with surveillance should be offered prophylactic resection of the at-risk segment with re-diversion[7]

Renal Function[16][25][21][32]​

  • Classical USS — renal function stable in 92% at median 41 mo; 77.5% of renal units normal at mean 14.6 yr
  • Mainz Pouch II — upper-tract function maintained / improved in 95% (Abol-Enein)
  • Pediatric USS — 8.7% late renal deterioration (comparable to colon-conduit 8.3%)
  • Radiographic deterioration in 23% of renal units in classical USS (severe in 7%)
  • Chronic renal insufficiency 6% at > 10 yr (Mayo Clinic)

Quality of Life[24][19][33]​

  • Bastian 2004 EORTC QLQ C-30 in Mainz Pouch II patients — no significant differences vs German reference population except for diarrhea; 100% daytime continence; 63% could distinguish between stool and urine
  • High volunteer-rate-of-recommendation in pouch series

Surveillance Protocol Summary​

Lifelong follow-up combines metabolic, infectious, renal, and oncologic surveillance:[7][27][30][31]

  • Serum electrolytes, blood gases, BMP — every 3 mo first year, then every 6 mo
  • Renal function — eGFR; nuclear GFR if creatinine unreliable
  • Vitamin B12 annually (if any ileum used)
  • Upper-tract imaging — ultrasound or CT for hydronephrosis / stones
  • Annual colonoscopy beginning 5–6 yr post-USS (continues even after re-diversion)
  • Cancer surveillance per primary-disease protocol
  • Bone density — consider given chronic acidosis exposure

See Also​

References​

1. Przydacz M, Corcos J. "Revisiting ureterosigmoidostomy, a useful technique of urinary diversion in functional urology." Urology. 2018;115:14–20. doi:10.1016/j.urology.2018.01.003

2. Goodwin WE, Scardino PT. "Ureterosigmoidostomy." J Urol. 1977;118(1 Pt 2):169–174. doi:10.1016/s0022-5347(17)57938-0

3. 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

4. Gerharz EW, Köhl UN, Weingärtner K, et al. "Experience with the Mainz modification of ureterosigmoidostomy." Br J Surg. 1998;85(11):1512–1516. doi:10.1046/j.1365-2168.1998.00904.x

5. Fisch M, Wammack R, Müller SC, Hohenfellner R. "The Mainz pouch II." Eur Urol. 1994;25(1):7–15. doi:10.1159/000475238

6. Cipolla R, Garcia RL. "Colonic polyps and adenocarcinoma complicating ureterosigmoidostomy: report of a case." Am J Gastroenterol. 1984;79(6):453–457.

7. Azimuddin K, Khubchandani IT, Stasik JJ, Rosen L, Riether RD. "Neoplasia after ureterosigmoidostomy." Dis Colon Rectum. 1999;42(12):1632–1638. doi:10.1007/BF02236220

8. Leadbetter GW, Zickerman P, Pierce E. "Ureterosigmoidostomy and carcinoma of the colon." J Urol. 1979;121(6):732–735. doi:10.1016/s0022-5347(17)56973-6

9. Steg A, Gibod LB. "Uretero-colic anastomosis by the 'cuff' or 'flap' procedure — Goodwin's modified technique: preliminary report." Eur Urol. 1975;1(3):159–161.

10. Fisch M, Wammack R, Müller SC, Hohenfellner R. "The Mainz pouch II (sigma-rectum pouch)." J Urol. 1993;149(2):258–263. doi:10.1016/s0022-5347(17)36050-0

11. el Mekresh MM, Hafez AT, Abol-Enein H, Ghoneim MA. "Double folded rectosigmoid bladder with a new ureterocolic antireflux technique." J Urol. 1997;157(6):2085–2089.

12. D'elia G, Pahernik S, Fisch M, Hohenfellner R, Thüroff JW. "Mainz pouch II technique: 10 years' experience." BJU Int. 2004;93(7):1037–1042. doi:10.1111/j.1464-410X.2003.04777.x

13. Hadzi-Djokic JB, Basic DT. "A modified sigma-rectum pouch (Mainz pouch II) technique: analysis of outcomes and complications on 220 patients." BJU Int. 2006;97(3):587–591. doi:10.1111/j.1464-410X.2006.05995.x

14. Fisch M, Wammack R, Hohenfellner R. "The sigma rectum pouch (Mainz pouch II)." World J Urol. 1996;14(2):68–72. doi:10.1007/BF00182560

15. Atta MA. "Detubularized isolated ureterosigmoidostomy: description of a new technique and preliminary results." J Urol. 1996;156(3):915–919. doi:10.1016/s0022-5347(01)65662-3

16. Bissada NK, Morcos RR, Morgan WM, Hanash KA. "Ureterosigmoidostomy: is it a viable procedure in the age of continent urinary diversion and bladder substitution?" J Urol. 1995;153(5):1429–1431. doi:10.1016/s0022-5347(01)67420-2

17. Nieh PT, Althausen AF, Dretler SP. "Staged ureterocolocolostomy urinary diversion." J Urol. 1978;120(4):402–406. doi:10.1016/s0022-5347(17)57199-2

18. Pettersson L, Tranberg J, Abrahamsson K, et al. "Half century of follow-up after ureterosigmoidostomy performed in early childhood." J Urol. 2013;189(5):1870–1875. doi:10.1016/j.juro.2012.11.179

19. Zabbo A, Kay R. "Ureterosigmoidostomy and bladder exstrophy: a long-term followup." J Urol. 1986;136(2):396–398. doi:10.1016/s0022-5347(17)44879-8

20. Koo HP, Avolio L, Duckett JW. "Long-term results of ureterosigmoidostomy in children with bladder exstrophy." J Urol. 1996;156(6):2037–2040.

21. Tollefson MK, Elliott DS, Zincke H, Frank I. "Long-term outcome of ureterosigmoidostomy: an analysis of patients with > 10 years of follow-up." BJU Int. 2010;105(6):860–863. doi:10.1111/j.1464-410X.2009.08811.x

22. Carswell JJ, Skeel DA, Witherington R, Otken LB. "Neoplasia at the site of ureterosigmoidostomy." J Urol. 1976;115(6):750–752. doi:10.1016/s0022-5347(17)59363-5

23. Obek C, Kural AR, Ataus S, et al. "Complications of the Mainz pouch II (sigma rectum pouch)." Eur Urol. 2001;39(2):204–211. doi:10.1159/000052437

24. Bastian PJ, Albers P, Hanitzsch H, et al. "Health-related quality of life following modified ureterosigmoidostomy (Mainz pouch II) as continent urinary diversion." Eur Urol. 2004;46(5):591–597. doi:10.1016/j.eururo.2004.06.007

25. Kälble T, Tricker AR, Friedl P, et al. "Ureterosigmoidostomy: long-term results, risk of carcinoma and etiological factors for carcinogenesis." J Urol. 1990;144(5):1110–1114. doi:10.1016/s0022-5347(17)39670-2

26. Stewart M, Macrae FA, Williams CB. "Neoplasia and ureterosigmoidostomy: a colonoscopy survey." Br J Surg. 1982;69(7):414–416. doi:10.1002/bjs.1800690720

27. Heidler H, Marberger M, Hohenfellner R. "The metabolic situation in ureterosigmoidostomy." Eur Urol. 1979;5(1):39–44. doi:10.1159/000473059

28. Hall MC, Koch MO, McDougal WS. "Metabolic consequences of urinary diversion through intestinal segments." Urol Clin North Am. 1991;18(4):725–735.

29. Caprilli R, Frieri G, Latella G, Gallucci M, Bracci U. "Electrolyte and acid-base imbalance in patients with rectosigmoid bladder." J Urol. 1986;135(1):148–150. doi:10.1016/s0022-5347(17)45550-9

30. Starling JR, Uehling DT, Gilchrist KW. "Value of colonoscopy after ureterosigmoidostomy." Surgery. 1984;96(4):784–790.

31. Berg NO, Fredlund P, Månsson W, Olsson SA. "Surveillance colonoscopy and biopsy in patients with ureterosigmoidostomy." Endoscopy. 1987;19(2):60–63. doi:10.1055/s-2007-1018236

32. Altwein JE, Jonas U, Hohenfellner R. "Long-term followup of children with colon conduit urinary diversion and ureterosigmoidostomy." J Urol. 1977;118(5):832–836. doi:10.1016/s0022-5347(17)58211-7

33. Miles-Thomas J, Gearhart JP, Gearhart SL. "An initial evaluation of pelvic floor function and quality of life of bladder exstrophy patients after ureterosigmoidostomy." J Gastrointest Surg. 2006;10(4):473–477. doi:10.1016/j.gassur.2006.01.001