Skip to main content

Ureterosigmoidostomy and Rectosigmoid Diversion

Classical ureterosigmoidostomy implants the ureters into the sigmoid colon, allowing urine to mix with stool and empty through the anus. Continence depends on anal function. It avoids an abdominal urinary appliance, but introduces substantial lifelong metabolic, upper-tract and colorectal surveillance needs.[1][2] It is a selected reconstructive option.[1][2] Simon performed the first ureterosigmoidostomy in 1852, for bladder exstrophy. Ileal conduits and continent reservoirs later largely replaced it.[5][3] The EAU 2026 bladder cancer guideline (section 6.7.5.a.4) describes ureterorectosigmoidostomy as rarely used because of high complication rates, including upper urinary tract infection and stone formation. It gives no strength rating for this statement.[24] Renewed interest comes from its ease, speed and applicability to minimally invasive surgery.[1]

The Mainz pouch II is a detubularized rectosigmoid modification. Its construction and procedure-specific evidence are covered on that companion page. It remains distinct from an isolated colon conduit, which drains to an abdominal stoma.

Selection and Counseling​

Consider rectosigmoid diversion only after reviewing the alternatives and the patient's ability to sustain follow-up. Important considerations include:

  • Anal continence and rectosigmoid function: assess baseline stool continence, urgency, bowel disease and prior surgery. Specialist functional testing may help when competence is uncertain.
  • Renal and metabolic reserve: impaired renal function, obstruction or recurrent upper-tract infection increases concern about the acid load from urine-exposed bowel.
  • Colorectal suitability: inflammatory bowel disease, neoplasia, significant radiation injury or an inherited colorectal cancer risk may make this route inappropriate.
  • Long-term access: reliable laboratory testing, imaging, endoscopy, treatment of acidosis and rapid evaluation of infection are needed. Appliance-free diversion still requires these long-term services. In a 2024 Malawi series of 21 women who received Mainz II diversion for irreparable fistula, eight died during follow-up and five were lost; the investigators suspected a metabolic contribution to seven deaths but could not establish their causes.[25]
  • Patient priorities: discuss daytime and nighttime leakage, bowel frequency, emptying routines, future conversion and cancer risk in addition to body image.[1][2][3][4]

Operative Principles and Modifications​

Classical techniques use ureterocolonic implantation into intact bowel; tunnel-based antireflux modifications were intended to limit ascending reflux. Goodwin and Scardino favored the open-sigmoid (transcolonic) approach with a long submucosal tunnel and direct ureter-to-bowel anastomosis, and advised mandatory bowel preparation and a lifelong low-chloride diet with sodium-potassium citrate.[5] Direct vision, viable ureter, preservation of blood supply and an unobstructed, tension-free anastomosis matter more than assigning a universal tunnel length.[5][2] An antireflux mechanism can itself obstruct.[5][2]

Mainz II opens the rectosigmoid along its antimesenteric aspect and closes it side to side into a low-pressure reservoir, without colostomy, augmentation or extensive bowel surgery. The pouch is fixed to the sacral promontory to lessen ureteral kinking, and dilated ureters can be implanted. In the original report of 47 patients (mean follow-up 10 months), basal pressure with the reservoir full was 24 cm H₂O and the highest peak pressure 35 cm H₂O, and all patients were continent by day.[6] Later series documented favorable pressure and continence measurements.[6][7][8]

Bowel preparation, ureteric stents, temporary drainage and postoperative emptying schedules should follow the actual reconstruction and institutional protocol. Sodium or potassium citrate use depends on renal function and electrolyte status. See Bowel preparation and Urinary acidifiers and alkalinizers.[5][9]

Other configurations, such as Atta's isolated detubularized pouch, have been described in small preliminary series. An inverted-U detubularized sigmoid pouch drains into the rectum while the left colon is fixed in continuity to the rectal ampulla, and ureters are implanted with a nipple technique. All 15 patients followed for 3 to 18 months passed urine (3 to 6 times daily) and solid feces (once daily) separately. Atta's preliminary series has no long-term malignancy outcomes.[10]

What Long-term Outcomes Show​

SourcePopulation and follow-upFindings and limits
Tollefson 201051 patients selected for more than 10 years of follow-up; median 15.7 years; 40 had the operation for malignancy47/51 reported total continence at the last physician interview; 22/51 had a late complication and 19/51 required another operation. Anastomotic stricture (11/51), recurrent pyelonephritis (8), stones (5), chronic renal insufficiency (3) and severe intractable acidosis (2) occurred. Oral agents for metabolic acidosis were prescribed to 32/51 (63%). Among 36/51 who underwent endoscopic surveillance, 11/36 (31%) had tubular adenomas with low or moderate dysplasia, including three in the sigmoid colon; no invasive colorectal carcinoma was identified in the cohort.[2]
Koo 1996, childhood exstrophy27 patients, average 17 years after diversionReported daytime continence was 92% and nighttime continence 58%; 18% developed significant upper-tract changes. Two patients had retention-associated hyperammonemia and acidosis.[3]
Zabbo 1986, exstrophy158 patients operated from 1925 to 1970; 52 reached by telephone34 still had a functioning ureterosigmoidostomy (30 with complete continence day and night) and 18 had required other diversion. Of patients surviving 15 or more years, 11% had colon cancer. Telephone follow-up of a minority of the original cohort limits interpretation.[20]
Bissada 199563 patients, median follow-up 41 monthsRenal function was reported stable in 92%, while imaging deteriorated in 23% of renal units. Patient-level biochemical outcomes and renal-unit imaging outcomes measure different things.[11]
Mainz II seriesDifferent indications, denominators and generally shorter follow-upD'elia: 102 evaluated patients (mean 46 months), day and night continence 97% and 95%, ureteric implantation stenosis 7.2% of 194 renal units, and 69% used oral alkalinizing drugs. Hadzi-Djokic: 220 operated; 177 (81%) had follow-up (median 21 months). Among those followed, all but three (99%) were continent and 92/177 (52%) required alkali and potassium. Obek: 50 evaluable patients (median 31 months), all but one continent, 30/50 on alkali and three hospitalized for severe acidosis and hypokalemia. Two later died after progressive deterioration; the authors considered probable malnutrition and metabolic abnormalities, without proving a single cause. Alkali treatment, obstruction, infection and occasional severe metabolic events accompany the high continence rates; see the dedicated page for analyzed denominators.[12][13][8]

The 2012 Cochrane review of intestinal urinary reconstruction found only five small trials (355 participants) across several comparisons, with limited methods and imprecise results.[14]

Metabolic and Upper-tract Complications​

Urine-exposed colon can absorb ammonium and other solutes and secrete bicarbonate, producing hyperchloremic metabolic acidosis. Severity depends on renal function, bowel exposure and emptying. In a comparison of 22 rectosigmoid-bladder and 25 classical ureterosigmoidostomy patients, acidosis occurred in 86% and 80%, and was less severe with the rectosigmoid bladder (pH 7.34 vs 7.29, p < 0.01).[22] In this cohort, hyperchloremia was uncommon and an elevated anion gap was frequent.[22] Infection or obstruction may precipitate deterioration. Hypokalemia can be substantial, and retention can cause hyperammonemia; new weakness, confusion, vomiting or systemic illness warrants urgent assessment.[9][15][3]

In Obek's Mainz II cohort, 50 of 60 patients were evaluable: 30 required oral alkalization, and three required hospitalization for severe acidosis and hypokalemia.[8]

Follow serum bicarbonate, potassium and renal function; investigate symptomatic infection, hydronephrosis, stones or impaired emptying. Select alkali and potassium replacement according to laboratory results and comorbidity. Chronic acidosis also raises concern about bone health. The drug-specific regimen belongs in the urinary alkalinizer hub. Routine B12 supplementation is not inherent to a pure colonic diversion; assess any ileal resection and other B12 risks separately.[9]

Colorectal Neoplasia​

Ureterocolonic anastomoses are at risk of adenoma and adenocarcinoma, often decades after diversion. A literature review gave an incidence of carcinoma of 2% to 15% with a latent period of 20 to 26 years, and polyps are more common than cancer.[19] Reported risk multipliers vary by population, age, follow-up and whether adenoma is counted with cancer, precluding a single lifetime percentage. Kälble found 3 carcinomas in 30 patients examined by sigmoidoscopy, an 8.5- to 10.5-fold increase over the general population, and noted that an excess over ileal conduits was not proved. Leadbetter estimated a 500-fold increase and about a 5% lifetime risk, with a development time of 6 to 50 years that was shorter in patients older than 40 years at surgery.[16][21] Mainz II retains this surveillance concern. Nitrosamine formation and inflammation are proposed contributors.[16][17][4]

Pettersson's exceptionally long childhood cohort assessed 24 patients after excluding an early postoperative death: seven developed invasive colorectal cancer and one carcinoma in situ. Mean latency to invasive cancer was 38 years, and five died from colorectal cancer. Six of the seven invasive cancers were poorly differentiated, and the risk of colorectal adenocarcinoma was 42 times that of the general Swedish population. Three cancers arose 1, 21 and 25 years after conversion to another diversion.[18] Pettersson's 7/24 invasive cancer finding in this childhood cohort supports long-term follow-up.[18] Zero cancers in smaller or shorter series yield limited long-term safety data.[18][2]

Endoscopic surveillance and anastomotic safety​

Arrange a documented urology–gastroenterology plan. The 2010 BSG guidance recommends annual flexible sigmoidoscopy from the tenth anniversary, examining through and just beyond the higher ureteric implantation; this is a Grade C recommendation. Continue after conversion unless the original ureteric anastomoses are known to have been removed.[4]

An older 1999 review proposed starting no later than five to six years. Individualize earlier or more extensive examination for symptoms, prior lesions, hereditary risk or the treating team's protocol.[19][4]

A polypoid structure at a ureteric implantation should not be snared as though it were an ordinary colonic polyp. The normal anastomosis may appear polypoid, and removal can injure it and cause urinary leakage. Suspicious lesions require coordinated assessment; carefully planned biopsy or resection differs from routine snare polypectomy. Lesions clearly remote from the implantation are assessed separately.[4]

Investigate bleeding, unexplained anemia, new obstruction or concerning bowel symptoms between scheduled visits. Confirmed neoplasia requires colorectal and urologic staging and a resection or diversion plan tailored to its site and extent. Difficulty attending surveillance should prompt active follow-up support and discussion of alternatives, not an automatic requirement for prophylactic bowel resection.[19][4]

Quality of Life​

In a Mainz pouch II series of 83 patients, 41 completed the EORTC QLQ-C30. All scales except diarrhea were comparable to a German reference population. Among the 31 Bonn respondents at a mean follow-up of 24.4 months, daytime continence was 100%; all but one rose to urinate at night, about one third voided more than three times nightly, and 63% could distinguish stool from urine. Only about half of the original patients were assessed (28 had died and 14 were lost to follow-up).[23]

Lifelong Follow-up​

  • Urinary and bowel function: day and night continence, emptying, stool frequency, pain and quality of life.
  • Metabolic and renal assessment: electrolytes including bicarbonate and potassium, creatinine and eGFR, and additional acid–base testing when indicated. Increase testing during early recovery, intercurrent illness or after changing replacement therapy; avoid a rigid one-size-fits-all schedule.
  • Upper tracts: periodic imaging, with prompt investigation of obstruction, recurrent febrile infection or declining renal function.
  • Endoscopy: follow the documented anastomotic surveillance plan and preserve the operative record if diversion is later converted.
  • Underlying disease: maintain any separate cancer or congenital-urology surveillance.[1][2][9][4]

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. 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

3. Koo HP, Avolio L, Duckett JW Jr. Long-term results of ureterosigmoidostomy in children with bladder exstrophy. J Urol. 1996;156(6):2037–2040. PubMed. doi:10.1016/s0022-5347(01)65429-6

4. Cairns SR, Scholefield JH, Steele RJ, et al. Guidelines for colorectal cancer screening and surveillance in moderate and high risk groups (update from 2002). Gut. 2010;59:666–690. Ureterosigmoidostomy section, pp. 674–675. doi:10.1136/gut.2009.179804.

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

6. 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

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

8. 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

9. Hall MC, Koch MO, McDougal WS. Metabolic consequences of urinary diversion through intestinal segments. Urol Clin North Am. 1991;18(4):725–735. PubMed. doi:10.1016/s0094-0143(21)00373-6

10. 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

11. 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

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. 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

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

16. 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

17. 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

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. 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

20. 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

21. Leadbetter GW Jr, 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

22. 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

23. 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

24. European Association of Urology. EAU Guidelines on Muscle-invasive and Metastatic Bladder Cancer. 2026. Section 6.7.5.a.4, Continent cutaneous urinary diversion. Guideline.

25. Patel TD, Chipungu EB, Draganchuk JM, Chalamanda C, Wilkinson JP. "Mainz II urinary diversion in low-resource settings: patient outcomes in women with irreparable fistula in Malawi." AJOG Glob Rep. 2024;4(2):100350. doi:10.1016/j.xagr.2024.100350