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. It is a selected reconstructive option, not a default alternative whenever a neobladder or catheterizable reservoir is unsuitable.[1][2]

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; a single water-holding test should not be treated as a guarantee of postoperative continence.
  • 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. Assess the actual bowel and cancer risk rather than treating all family histories alike.
  • Long-term access: reliable laboratory testing, imaging, endoscopy, treatment of acidosis and rapid evaluation of infection are essential. Avoiding appliances does not make this a low-maintenance operation for a setting without those services.
  • 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. Direct vision, viable ureter, preservation of blood supply and an unobstructed, tension-free anastomosis matter more than assigning a universal tunnel length. An antireflux mechanism can itself obstruct and does not eliminate infection or upper-tract deterioration.[5][2]

Mainz II opens the rectosigmoid along its antimesenteric aspect and refashions it to reduce coordinated high-pressure contractions. Early series documented favorable pressure and continence measurements, but detubularization does not guarantee low pressure in every patient, eliminate urgency or remove the metabolic and neoplastic consequences of ureterocolonic diversion. Do not infer comparative superiority from unrelated classical and modified series.[6][7][8][4]

Bowel preparation, ureteric stents, temporary drainage and postoperative emptying schedules should follow the actual reconstruction and institutional protocol. Historical instructions for mandatory mechanical preparation, fixed stent durations or lifelong sodium/potassium citrate are not universal contemporary prescriptions; electrolyte therapy requires individual renal, potassium and sodium assessment. See Bowel preparation and Urinary acidifiers and alkalinizers.[5][9]

Other configurations, such as Atta's isolated detubularized pouch, were described in small preliminary series. Passing urine and stool separately in 15 patients followed for 3–18 months does not demonstrate elimination of carcinogenic exposure or long-term cancer protection. Such variations should not be presented as established solutions to the malignancy risk.[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 years48/51 reported complete continence; 22/51 had a late complication and 19/51 required another operation. Stricture, pyelonephritis, stones, renal impairment and severe acidosis occurred. These are outcomes among long-term followed patients, not an inception cohort free of survivor selection.[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. Daytime dryness cannot stand in for night function or metabolic safety.[3]
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-upHigh reported continence coexists with alkali treatment, obstruction, infection and occasional severe metabolic events; 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. It did not establish a superior diversion. It also does not justify claiming that modified ureterosigmoidostomy is equivalent or superior to an ileal conduit or neobladder.[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. 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]

Detubularization does not remove this burden. 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. Those observations should not be diluted into a claim that modified diversion causes only mild metabolic disturbance.[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. Historical risk multipliers vary enormously with population, age, follow-up and whether adenoma is counted with cancer; they should not be combined into a single lifetime percentage. Mainz II retains this surveillance concern. Nitrosamine formation and inflammation are proposed contributors, not proof of a single mechanism or a preventive drug strategy.[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. Three cancers arose 1, 21 and 25 years after conversion to another diversion. These findings establish the importance of long-term follow-up; 7/24 is not a universal contemporary lifetime risk. Conversely, zero cancers in a smaller or shorter series does not establish safety.[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. These are differing historical recommendations, not a newly proven single schedule. Individualize earlier or more extensive examination for symptoms, prior lesions, hereditary risk or the treating team's protocol.[19][4]

Do not snare a polypoid structure at a ureteric implantation 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/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]

Lifelong Follow-up​

  • Urinary and bowel function: day/night continence, emptying, stool frequency, pain and quality of life.
  • Metabolic and renal assessment: electrolytes including bicarbonate and potassium, creatinine/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.

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.

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