Skip to main content

Mainz Pouch II

The Mainz Pouch II (also known as the sigma-rectum pouch or rectosigmoid pouch) is a detubularized, low-pressure rectosigmoid reservoir for continent urinary diversion, developed by Margit Fisch, Rainer Wammack, and Rudolf Hohenfellner at the University of Mainz in 1991.[1][2][3][4] It represents a modern, low-pressure modification of classical ureterosigmoidostomy that applies the principles of detubularization and spherical reconfiguration to the rectosigmoid colon, eliminating the high-pressure contractions and poor continence of the classical technique. The Mainz Pouch II is distinguished by its simplicity, reproducibility, and absence of any stoma, external appliance, or self-catheterization — the patient voids urine per rectum using the native anal sphincter for continence.

Historical Development​

The Problem with Classical Ureterosigmoidostomy​

Classical ureterosigmoidostomy — direct implantation of the ureters into the intact sigmoid colon — was one of the earliest forms of urinary diversion (19th century). It was plagued by high intraluminal pressures from intact peristalsis (causing reflux and upper-tract deterioration), urge incontinence, hyperchloremic metabolic acidosis, ascending pyelonephritis, and most importantly, secondary malignancy at the ureterocolonic anastomosis (2–15% incidence; latency 20–26 yr; risk 100–550× the general population).[5][6][7][8][9][10] These complications led to near-abandonment of the classical technique by the 1970s–1980s.

Timeline of the Mainz Pouch II​

  • 1991 — Fisch and Hohenfellner described the sigma-rectum pouch — applying detubularization and reconfiguration (already proven in Mainz Pouch I) to the rectosigmoid.[2][3][4]
  • 1993 — 47-patient series in J Urol: all continent during the day, all but one dry at night; basal pouch pressure 24 cm H₂O / peak 35 cm H₂O.[4]
  • 1994 — 72-patient series (incl. 15 children) in Eur Urol.[3]
  • 1996 — 73-patient series (59 adults, 14 children), mean f/u 12.7 mo: daytime continence 94.5%, nighttime 98.6%, early complications 6.8%, late 10.9%.[2]
  • 1996 — Gilja (Croatia) confirmed urodynamic benefits in 20 patients (post-op contraction pressure 19.1 cm H₂O vs preoperative 27.6, p < 0.05).[12]
  • 1998 — Gerharz (Mainz) 34-patient prospective series concluded that "bowel frequency and urge incontinence, the major weaknesses of classical ureterosigmoidostomy, can be overcome by detubularization."[5]
  • 2001 — Obek (Turkey) 60-patient series: all but 1 continent, but 60% required oral alkalizing supplementation, 6% hospitalized for severe acidosis, and 2 deaths from progressive metabolic / nutritional failure.[13]
  • 2004 — D'Elia (Mainz) definitive 10-year experience: 123 patients, mean f/u 46.2 mo; daytime 97% / nighttime 95% continence; ureteric stenosis 7.2%; 69% required alkali.[1]
  • 2004 — Bastian QoL study (n = 41): EORTC QLQ C-30 comparable to German reference population on all scales except diarrhea; 100% daytime continence; 63% could distinguish stool from urine.[14]
  • 2004 — Nitkunan (London) 17-patient long-term f/u (mean 6.4 yr): good outcomes as primary procedure but poor results when used to revise failed classical ureterosigmoidostomy.[15]
  • 2006 — Hadži-Djokić largest series: 220 patients, median f/u 21 mo; 99% continent day and night; 52% required alkali; ureteric stenosis in 11.[16]
  • 2006 — Pahernik pediatric series: 38 children (mean age 5; mostly bladder exstrophy), mean f/u 9.3 yr; 100% daytime / 91.4% nighttime continence; reimplantation needed in 14.5% of RUs; 69% required alkali.[17]
  • 2024 — Jing (China) first robotic RARC + Mainz Pouch II series: 37 patients, median f/u 23 mo; daytime 91.9% / nighttime 86.5% continence; 94.6% satisfied.[18]

Design Principles​

The Mainz Pouch II applies the same fundamental principles proven in Mainz Pouch I to the rectosigmoid colon.[1][2][3][4]

  1. Detubularization of the rectosigmoid disrupts coordinated circular-muscle contractions and eliminates high-pressure peristaltic waves.
  2. Spherical reconfiguration — the opened bowel plate is folded and sutured side-to-side, creating a near-spherical low-pressure reservoir (Laplace's law).
  3. Anal sphincter continence — the native internal and external anal sphincters provide continence; no stoma, appliance, or CIC.
  4. Antireflux ureteral reimplantation — submucosal tunnel (Goodwin-Hohenfellner) or serous-lined extramural tunnel (Abol-Enein).[1][19]

Advantages over classical ureterosigmoidostomy:

ParameterClassicalMainz Pouch II
Bowel modificationNone (intact sigmoid)Detubularized + reconfigured
Peak intraluminal pressure> 48–50 cm H₂O19–35 cm H₂O
Daytime continence70–85%94.5–100%
Nighttime continence50–70%86.5–99%
Voiding frequency (day)8–124–6
Upper-tract deteriorationCommon (30–50%)Uncommon (5–7.2% stenosis)
Metabolic acidosisSevere / commonMild; 52–69% need oral alkali

The pouch is fixed to the sacral promontory or psoas muscle to prevent descent and ureteral kinking — a key technical detail that reduces upper-tract complications.[2][4][12]

Surgical Technique​

Standard Mainz Pouch II (Fisch / Hohenfellner)​

  1. Preoperative anal sphincter assessment is mandatory. Patients must retain a 300–400 mL water enema for ≥ 2 hours without leakage. Rectal manometry assesses sphincter pressures and rectal compliance.[1][3][11]
  2. Bowel preparation — standard mechanical prep.
  3. Rectosigmoid mobilization — approximately 20–30 cm of sigmoid + upper rectum are mobilized, preserving the mesentery.
  4. Detubularization — the rectosigmoid is opened along the antimesenteric border (taenia libera) for ~ 15–20 cm.
  5. Side-to-side anastomosis — the opened edges are folded and sutured side-to-side with running absorbable sutures, posterior wall first.
  6. Ureteral reimplantation — submucosal tunnel (Goodwin-Hohenfellner; the original method) or serous-lined extramural tunnel (Abol-Enein technique, preferred for dilated ureters).[1][19]
  7. Pouch fixation — the completed pouch is fixed to the sacral promontory with nonabsorbable sutures to prevent descent and ureteral kinking.[2][4][12]
  8. Stenting and drainage — ureteral stents are brought out through the anus; rectal tube placed; stents removed at 10–14 days.

Modifications​

  • Hadži-Djokić modification — longer detubularization (~ 25–30 cm) with a wider, more spherical pouch; both ureters reimplanted via Goodwin-Hohenfellner submucosal tunnel. Used in the largest published series (220 patients).[16]
  • Dismembered detubularized rectosigmoid bladder (Elabbady 1998) — the sigmoid is completely transected ~ 30 cm proximal to the peritoneal reflection; proximal two-thirds detubularized into the pouch; terminal colon reanastomosed end-to-side to anterior rectum just above the peritoneal reflection. Creates separation of fecal and urinary streams (8 of 20 patients voided clear urine separated from stools); mean basal pressure only 9.7 cm H₂O with mean compliance 32.3.[20]
  • Valved S-shaped rectosigmoid pouch (Sundin/Mansi 1993) — adds an intussusception valve to prevent proximal colonic reflux; capacity 400–900 mL (mean 600); intraluminal pressure 10–34 cm H₂O (mean 22); all 15 patients continent day and night; requires temporary protective transverse colostomy.[21]

Functional Outcomes​

SeriesnFollow-upDaytimeNighttimeVoiding (day/night)Notes
Fisch 1993[4]47Mean 10 mo100%98%5 / 1First J Urol series; basal 24 cm H₂O
Fisch 1994[3]721–31 mo100%99%5 / 1Includes 15 children
Fisch 1996[2]73Mean 12.7 mo94.5%98.6%—6.8% early / 10.9% late complications
Gilja 1996[12]209–36 mo100%100%4 / 1Urodynamic confirmation of low pressure
Gerharz 1998[5]34Prospective100%97%—Mild acidosis in only 2 patients
Obek 2001[13]60Median 31 mo98%98%5.1 / 1.960% need alkali; 2 deaths from metabolic/nutritional failure
D'Elia 2004[1]123Mean 46.2 mo97%95%6 / 1Definitive 10-yr Mainz experience; 7.2% ureteric stenosis
Bastian 2004[14]41Mean 19 mo100%~ 95%VariableQoL ≈ German reference population
Nitkunan 2004[15]17Mean 6.4 yr83% (primary)Variable—Poor revision-procedure outcomes
Hadži-Djokić 2006[16]220Median 21 mo99%99%4.2 / 2.1Largest series; 52% need alkali
Pahernik 2006 (pediatric)[17]38Mean 9.3 yr100%91.4%—Mostly exstrophy; 69% need alkali
Jing 2024 (RARC)[18]37Median 23 mo91.9%86.5%6 / 3First robotic series; 94.6% satisfied

Urodynamics​

ParameterClassical UreterosigmoidostomyMainz Pouch II
Basal pressure21.4 cm H₂O19.3 cm H₂O (NS)
Mean contraction pressure27.6 cm H₂O (max 48)19.1 cm H₂O (p < 0.05)
Peak pressure (full reservoir)> 50 cm H₂O24–35 cm H₂O
CapacityLimited by contractions400–900 mL (valved modification)
ComplianceLowHigh (mean 32.3 in dismembered modification)

The critical finding: while basal pressure is not significantly changed by detubularization, high-pressure peristaltic contractions are effectively eliminated (27.6 → 19.1 cm H₂O, p < 0.05).[12]

Complications​

Perioperative mortality is 0% across all major series.[1][2][13][16][18]

Ureteric Implantation Stenosis​

SeriesStenosis RateManagement
Fisch 1996[2]6.8%Open repair
D'Elia 2004[1]7.2% (14/194 RUs)Open repair (13), balloon (1)
Hadži-Djokić 2006[16]5% (11/220)Open repair
Pahernik 2006 (pediatric)[17]10.1% stenosis; 4.3% refluxReimplantation
Bastian 2004[19]2% (2/81 RUs)Reimplantation

Hyperchloremic Metabolic Acidosis​

The mechanism is reabsorption of urinary chloride and ammonium across colonic mucosa, with loss of bicarbonate. Severity depends on contact surface area, contact duration (voiding frequency), and baseline renal function.[1][12][13]

SeriesPatients on AlkaliSevere (Hospitalized)
Gerharz 1998[5]6% (mild)None
Obek 2001[13]60%6%; 2 deaths from metabolic / nutritional failure
D'Elia 2004[1]69% (BE < −2.5 mmol/L)None clinically evident
Hadži-Djokić 2006[16]52%Not specified
Pahernik 2006 (pediatric)[17]69%1 child
Bastian 2004[14]30% initially → 8% long-termNone

Key safety message: Obek's 2 deaths from progressive malnutrition and metabolic abnormalities emphasize that patient selection and compliance with alkalizing supplementation are critical. See Urinary Acidifiers & Alkalinizers.[13]

Other Complications​

  • Pyelonephritis 6–17% across series, often associated with stenosis or reflux.[2][13][16][17]
  • Hydronephrosis ~ 5% of RUs (Obek series).[13]
  • Serum creatinine remained within normal limits in all children in the pediatric series.[17]

Secondary Malignancy Risk​

This is the most important long-term concern with any form of ureterosigmoidostomy, including the Mainz Pouch II.[6][7][9][10][22][23][24]

Classical Ureterosigmoidostomy​

  • Incidence of carcinoma: 2–15%.[6]
  • Risk vs general population: 100–550× greater.[8][10]
  • Latency: 20–26 yr (range 6–50).[6][7]
  • Location: almost exclusively at the ureterocolonic anastomosis.[6][9]
  • Pathogenesis: urine-and-feces interaction at the healing colonic mucosa → endogenous N-nitrosamine formation by bacterial reduction of urinary nitrate + endogenous amines → DNA damage from neutrophil-derived reactive oxygen radicals at the healing anastomosis.[6][7][25]
  • Progression: classical adenoma–carcinoma sequence (polyps → dysplasia → adenocarcinoma).[6][8][9]

Mainz Pouch II — Is the Risk Lower?​

Evidence is mixed. In the multicenter German analysis of 17,758 urinary diversions (Kälble 2011), tumor risk in ureterosigmoidostomy was 2.58% — significantly higher than every other form of continent diversion (p < 0.05).[22] No cases of secondary malignancy have been reported in the major Mainz Pouch II series to date, but follow-up is mostly < 10 years.[1][5][16][17] In the pediatric series, annual rectosigmoidoscopy in 16 patients with > 10 years of follow-up showed no pathological findings.[17] The theoretical concern remains because the Mainz Pouch II still involves mixing of urine and feces at the ureterocolonic anastomosis — the same pathogenic mechanism.[22][23][24][26]

Surveillance​

  • Annual colonoscopy / rectosigmoidoscopy beginning at postoperative year 5 (some recommend year 10 in children).[6][9][17][23]
  • Lifelong surveillance is mandatory.
  • Polyps at the ureterocolonic anastomosis must be removed and biopsied.
  • Obstructive urinary symptoms developing > 2 years after surgery should raise suspicion for neoplasia.

Quality of Life​

The Bastian EORTC QLQ C-30 study (n = 41) is the only validated QoL data for Mainz Pouch II.[14]

  • No statistically significant differences between males and females on any functional or symptom scale.
  • All scales except diarrhea were comparable to the German reference population.
  • 100% daytime continence; 63% could distinguish stool from urine.
  • About one-third had to urinate > 6 times/day and > 3 times/night.
  • The relatively high nighttime voiding frequency was not felt to be disturbing by patients — a measure of adaptability.

The robotic series (Jing 2024): 94.6% satisfied with continence; 56.8% very satisfied. Achieving RC-pentafecta correlated with better satisfaction (7.3 vs 5.5, p = 0.034). Mean PAC-SYM constipation score was 9.50 (mild).[18]

Pediatric Experience​

The Mainz Pouch II is particularly valuable in children with bladder exstrophy and incontinent epispadias, where stoma-free, appliance-free, catheterization-free diversion is especially desirable.[3][17]

ParameterResult
Total children38 (mean age 5)
IndicationsExstrophy/epispadias 33; failed primary reconstruction 14; conversion from incontinent diversion 6
Mean follow-up9.3 years
Daytime continence100%
Nighttime continence91.4%
Pyelonephritis15.8% (mostly with stenosis)
Ureteral reimplantation required14.5% of RUs (10/69) — 7 stenosis, 3 reflux
Serum creatinineNormal in all
Alkali supplementation69%
Clinical acidosis requiring hospitalization1 child
Rectosigmoidoscopy (> 10 yr)No pathological findings (16 patients)

Source: Pahernik 2006.[17]

Comparison with Other Continent Diversions​

FeatureMainz Pouch IIMainz Pouch I (Cutaneous)Ileal ConduitOrthotopic Neobladder
StomaNoneYes (catheterizable)Yes (incontinent)None
External applianceNoneNoneYesNone
Self-catheterizationNoneYes (CIC q4–6 h)NoneSometimes
Continence mechanismAnal sphincterAppendix / nipple valveNoneUrethral sphincter
Continence rate94.5–100%82–92.8%N/A87–96%
Metabolic acidosis52–69% need alkali37% need alkaliMildMild
Secondary malignancy riskHighest (urine + feces mixing)Low (0.14%)Minimal (0.02%)Minimal (0.05%)
Surgical complexitySimplestComplexSimpleComplex
Bowel segmentRectosigmoid (in situ)Cecum + ileum (isolated)Ileum (isolated)Ileum (isolated)
Suitable for childrenYes (especially exstrophy)YesYesRarely

Patient Selection​

Indications.[1][11][16][17]

  • Radical cystectomy for bladder cancer (most common — ~75% of Mainz patients).
  • Bladder exstrophy / incontinent epispadias (especially in children).
  • Irreparable traumatic loss of the sphincteric urethra.
  • Failed primary bladder reconstruction.
  • Conversion from incontinent urinary diversion.
  • Patients who refuse a stoma or cannot perform self-catheterization.

Absolute contraindications.

  • Incompetent anal sphincter — the single most important contraindication. Preoperative assessment with a water-enema retention test is mandatory; the patient must retain 300–400 mL for ≥ 2 hours without leakage.[1][3][11]
  • Severe baseline renal insufficiency (the colonic-mucosa metabolic burden is poorly tolerated with reduced eGFR).
  • Inability to comply with lifelong alkali therapy and lifelong colonoscopic surveillance.
  • Severe colonic disease (IBD, prior radiation colitis, diverticular disease, colonic neoplasia).
  • Prior pelvic radiotherapy is a relative contraindication — Obek's death cohort included a previously irradiated female with pre-existing severe metabolic compromise.[13]

Strengths and Limitations​

Strengths

  • No stoma, no appliance, no self-catheterization — the only continent diversion with this triad.[1][2]
  • Excellent continence — 94.5–100% daytime, 86.5–99% nighttime across series.[1][2][16]
  • Surgically simple — no need for isolated bowel segments, complex bowel anastomoses, or stomal construction.
  • Validated in pediatric / exstrophy populations where stoma-free diversion is especially valuable.[17]
  • Quality of life comparable to general reference population on validated instruments.[14]
  • Robotic feasibility now demonstrated.[18]

Limitations

  • Highest secondary-malignancy risk of any continent diversion — 2.58% in the Kälble multicenter analysis; lifelong colonoscopic surveillance mandatory.[22]
  • Hyperchloremic metabolic acidosis — 52–69% require alkali; severe acidosis with potential lethality reported in poorly selected / non-adherent patients.[1][13][17]
  • Anal sphincter integrity is mandatory — no option for patients with sphincter compromise.
  • Poor results when used to revise failed classical ureterosigmoidostomy.[15]
  • No isolation of urine from feces at the ureterocolonic anastomosis — the persistent pathogenic substrate for malignancy.
  • Diarrhea is the one QoL domain that diverges from population norms.[14]

Current Status and Legacy​

The Mainz Pouch II remains a niche but legitimate continent urinary diversion, particularly valuable in pediatric exstrophy cohorts, in patients who refuse a stoma and cannot perform CIC, and in low-resource settings where lifelong appliance access is uncertain. Its key contributions:

  1. Established that detubularization + reconfiguration can be applied to the rectosigmoid in situ, eliminating the high-pressure contractions of the classical technique while preserving anal-sphincter continence.[1][2][4][12]
  2. Demonstrated that stoma-free, appliance-free, catheterization-free continent diversion is feasible with excellent continence outcomes.[1][2][16]
  3. Provided validated QoL data showing that patients adapt to per-rectum voiding with reasonable acceptance.[14]
  4. Established that the technique is safe and effective in children with bladder exstrophy at near-decade follow-up.[17]
  5. Robotic feasibility has now been demonstrated, opening minimally-invasive applications.[18]

The technique should not be offered without formal anal-sphincter testing, lifelong alkali surveillance, and a clear lifelong colonoscopic-surveillance program — and its secondary-malignancy concern remains unresolved.

Key Takeaways​

  1. The Mainz Pouch II is a detubularized rectosigmoid pouch that voids per rectum via the native anal sphincter — no stoma, no appliance, no CIC.[1][2][4]
  2. Detubularization eliminates the high-pressure peristaltic contractions of the classical technique (27.6 → 19.1 cm H₂O, p < 0.05), achieving 94.5–100% daytime / 86.5–99% nighttime continence.[1][2][12][16]
  3. 52–69% of patients require alkali supplementation for hyperchloremic metabolic acidosis, and severe noncompliance can be lethal.[1][13][17]
  4. Anal-sphincter competence is a mandatory prerequisite — confirmed by the 300–400 mL water-enema retention test.[1][3][11]
  5. Secondary malignancy risk at the ureterocolonic anastomosis is the most important long-term concern (2.58% in multicenter analysis; latency 20–26 yr); lifelong colonoscopic surveillance starting at year 5 is mandatory.[6][22]
  6. Particularly valuable in children with bladder exstrophy / epispadias, where stoma-free diversion is most desirable; 9.3-year follow-up data show 100% daytime continence with stable upper tracts.[17]
  7. Poor revision technique — using Mainz Pouch II to salvage failed classical ureterosigmoidostomy yields inferior results.[15]

See Also​

References​

1. D'Elia G, Pahernik S, Fisch M, Hohenfellner R, Thüroff JW. "Mainz Pouch II Technique: 10 Years' Experience." BJU Int. 2004;93(7):1037–42. doi:10.1111/j.1464-410X.2003.04777.x

2. 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

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

4. Fisch M, Wammack R, Müller SC, Hohenfellner R. "The Mainz Pouch II (Sigma Rectum Pouch)." J Urol. 1993;149(2):258–63. doi:10.1016/s0022-5347(17)36050-0

5. Gerharz EW, Köhl UN, Weingärtner K, et al. "Experience With the Mainz Modification of Ureterosigmoidostomy." Br J Surg. 1998;85(11):1512–6. doi:10.1046/j.1365-2168.1998.00904.x

6. Azimuddin K, Khubchandani IT, Stasik JJ, Rosen L, Riether RD. "Neoplasia After Ureterosigmoidostomy." Dis Colon Rectum. 1999;42(12):1632–8. doi:10.1007/BF02236220

7. 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):1110–4. doi:10.1016/s0022-5347(17)39670-2

8. Cipolla R, Garcia RL. "Colonic Polyps and Adenocarcinoma Complicating Ureterosigmoidostomy: Report of a Case." Am J Gastroenterol. 1984;79(6):453–7. PMID: 6731435

9. Stewart M, Macrae FA, Williams CB. "Neoplasia and Ureterosigmoidostomy: A Colonoscopy Survey." Br J Surg. 1982;69(7):414–6. doi:10.1002/bjs.1800690720

10. Leadbetter GW, Zickerman P, Pierce E. "Ureterosigmoidostomy and Carcinoma of the Colon." J Urol. 1979;121(6):732–5. doi:10.1016/s0022-5347(17)56973-6

11. Djokić JH, Milojević B, Pejčić T, et al. "Sigma-Rectum Pouch (Mainz Pouch II)." Acta Chir Iugosl. 2014;61(1):29–34. PMID: 25080873

12. Gilja I, Kovacić M, Radej M, et al. "The Sigmoidorectal Pouch (Mainz Pouch II)." Eur Urol. 1996;29(2):210–5. PMID: 8647150

13. Obek C, Kural AR, Ataus S, et al. "Complications of the Mainz Pouch II (Sigma Rectum Pouch)." Eur Urol. 2001;39(2):204–11. doi:10.1159/000052437

14. 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):591–7. doi:10.1016/j.eururo.2004.06.007

15. Nitkunan T, Leaver R, Patel HR, Woodhouse CR. "Modified Ureterosigmoidostomy (Mainz II): A Long-Term Follow-Up." BJU Int. 2004;93(7):1043–7. doi:10.1111/j.1464-410X.2004.04778.x

16. 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):587–91. doi:10.1111/j.1464-410X.2006.05995.x

17. Pahernik S, Beetz R, Schede J, Stein R, Thüroff JW. "Rectosigmoid Pouch (Mainz Pouch II) in Children." J Urol. 2006;175(1):284–7. doi:10.1016/S0022-5347(05)00035-2

18. Jing S, Yang E, Luo Z, et al. "Perioperative Outcomes and Continence Following Robotic-Assisted Radical Cystectomy With Mainz Pouch II Urinary Diversion in Patients With Bladder Cancer." BMC Cancer. 2024;24(1):127. doi:10.1186/s12885-024-11874-x

19. Bastian PJ, Albers P, Haferkamp A, Schumacher S, Müller SC. "Modified Ureterosigmoidostomy (Mainz Pouch II) in Different Age Groups and With Different Techniques of Ureteric Implantation." BJU Int. 2004;94(3):345–9. doi:10.1111/j.1464-410X.2004.04963.x

20. Elabbady AA, Elabbasy WI, Arafa AF, Atta MA, Abdel-Rahman M. "A Simple Technique for Urinary Diversion: The Dismembered Detubularized Rectosigmoid Bladder With Distal Colorectostomy." J Urol. 1998;160(3 Pt 1):714–7. doi:10.1016/S0022-5347(01)62765-4

21. Sundin T, Mansi MK. "The Valved S-Shaped Rectosigmoid Pouch for Continent Urinary Diversion." J Urol. 1993;150(3):838–42. doi:10.1016/s0022-5347(17)35627-6

22. Kälble T, Hofmann I, Riedmiller H, Vergho D. "Tumor Growth in Urinary Diversion: A Multicenter Analysis." Eur Urol. 2011;60(5):1081–6. doi:10.1016/j.eururo.2011.07.006

23. Austen M, Kälble T. "Secondary Malignancies in Different Forms of Urinary Diversion Using Isolated Gut." J Urol. 2004;172(3):831–8. doi:10.1097/01.ju.0000134890.07434.8e

24. Li R, Baack Kukreja JE, Kamat AM. "Secondary Tumors After Urinary Diversion." Urol Clin North Am. 2018;45(1):91–9. doi:10.1016/j.ucl.2017.09.010

25. Gittes RF. "Carcinogenesis in Ureterosigmoidostomy." Urol Clin North Am. 1986;13(2):201–5. PMID: 3705198

26. Pickard R. "Tumour Formation Within Intestinal Segments Transposed to the Urinary Tract." World J Urol. 2004;22(3):227–34. doi:10.1007/s00345-004-0438-4