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Double T-Pouch

The Double T-pouch is a continent cutaneous ileal reservoir using a serosa-lined flap-valve mechanism for two distinct functions: an afferent limb to limit reflux toward the ureters and an efferent limb to provide continence at a catheterizable stoma. Stein and Skinner described this application in 2001. It is separate from the orthotopic T-pouch, which drains through the urethra.[1][2]

Patient selection, the ability to catheterize reliably and lifelong reservoir follow-up are covered in Urinary Diversion Principles. The clinical evidence for the Double T pouch is limited to small series.

Historical Development​

  • 1998. The orthotopic T pouch replaced the Kock afferent nipple with a serosa-lined ileal tunnel. In the first 40 patients (November 1996 to August 1997; mean follow-up 10.5 months), there were no late complications or reflux, and the upper tracts were unchanged or improved.[3]
  • 1998. Bochner's pig study evaluated the serosa-lined valve as an afferent or efferent mechanism (see below).[6]
  • 2001. Stein and Skinner described the T-mechanism as the afferent limb of the orthotopic T pouch and as the afferent and efferent limbs of the cutaneous Double T pouch.[1][2]
  • 2002. Marino and Laudi reported the first independent series of a cutaneous T pouch, in 18 patients.[8]
  • 2003. Kurzrock, Skinner and Stein described the Hemi-T augment for pediatric patients.[9]
  • 2004. Stein reported 209 patients with the orthotopic T pouch.[5]
  • 2008. Seifert reported 19 patients with the cutaneous Double T pouch.[14]
  • 2012. Agarwal described the PGIMER modification with Yang–Monti tubes.[7]
  • 2015. USC-STAR compared the orthotopic T pouch with the Studer pouch.[11]

Rationale and Valve Mechanics​

The T mechanism was developed to avoid intussusception of an ileal nipple. The original orthotopic report described problems of the Kock afferent nipple, including stones, stenosis and extussusception, and proposed a serosa-lined tunnel as an alternative.[3][4]

A vascularized ileal tube lies within a tunnel formed by the adjacent reservoir limbs. The surrounding reservoir wall provides support for a flap-valve effect. The afferent and efferent applications have different clinical requirements: the inlet must drain the upper tracts without obstruction, whereas the outlet must be continent while still permitting reliable catheter passage.[1][2]

Avoiding intussusception removes the possibility of nipple extussusception in that component. The reconstruction may still contain foreign material and develop reservoir calculi despite avoiding exposed valve staples.[3][5]

T-mechanism construction​

Stein and Skinner describe the T-mechanism as a flap valve built from a short segment of intact, non-detubularized ileum that stays on its vascular pedicle.[1][3]

  1. The intact ileal tube is laid in a trough between two adjacent limbs of the detubularized reservoir.
  2. The serosal surfaces of the adjacent limbs are sutured over the tube, forming a serosa-lined extramural tunnel.
  3. As the reservoir fills, intraluminal pressure compresses the tube within the tunnel. In the afferent limb this blocks reflux; in the efferent limb it prevents leakage.
  4. The tunnel yields to the external pressure of a catheter, so the tube can be catheterized.

What the animal experiment established​

Bochner evaluated four valve configurations in an in-vivo pig model, immediately after construction and at four weeks. At four weeks, a 30 Fr tube in a 1 cm tunnel leaked at 19 cm H₂O; extending that tunnel to 2 cm prevented leakage under the tested conditions. It does not validate a safe storage pressure of 100 cm H₂O. A valve that resists leakage in an experiment does not make high-pressure storage acceptable.[6]

Operative Design​

The named technique has several modifications. Its shared elements are:[1][2][7]

  1. Select viable ileum with sufficient mesenteric reach for the reservoir, both limbs and the planned stoma; restore bowel continuity.
  2. Detubularize and reconfigure the reservoir segment to support low-pressure storage.
  3. Construct the afferent and efferent channels on their vascular pedicles, either from appropriately configured ileal tubes or from retubularized Yang–Monti segments in the PGIMER modification.
  4. Embed the channels within serosa-lined extramural tunnels while maintaining their perfusion and avoiding angulation or excessive compression.
  5. Implant the ureters into the afferent segment and bring the efferent segment to an accessible, catheterizable skin stoma.
  6. Close and drain the reservoir, then teach and verify a catheterization plan that keeps the reservoir decompressed.

The published methods should be followed as a complete construction rather than combining measurements from orthotopic T-pouch, Double T and PGIMER descriptions. Catheterization frequency is adjusted to capacity, urine production and storage pressure; an arbitrary four-to-six-hour interval is not sufficient for every patient.

PGIMER modification using Yang–Monti tubes​

Agarwal reported eight adults treated in 2008–2011. Proximal and distal short ileal segments were retubularized as Yang–Monti channels; the intervening bowel formed a W reservoir. The channels were embedded in serosa-lined extramural tunnels, the ureters joined the proximal tube using the Wallace principle, and the distal tube formed a flush stoma.[7]

The published technique harvested a 45–50 cm segment of terminal ileum, sparing the distal 25 cm of terminal ileum. The proximal 3 cm and distal 3–6 cm were separated on their pedicles and fashioned into Yang–Monti tubes (one proximal, one or two distal). The middle 40–45 cm was detubularized and folded into a W, with the serosa of adjacent loops sutured together close to the mesentery. The pouch was closed transversely over an 18 Fr pouchostomy tube and a 16 Fr stomal catheter, and the ureters were implanted over 6–8 Fr infant feeding tubes exteriorized through the pouch.[7] The bowel measurements must accommodate both channels without compromising their pedicles.[7]

A textbook description of a related continent ileal pouch with serosa-lined troughs uses 48 cm of ileum for the W-shaped reservoir (4 × 12 cm), plus a 6–8 cm oral segment tapered over a 30 CH catheter for the nonrefluxing ureteral anastomosis and an 8–10 cm aboral segment tapered over an 18 CH catheter for continence.[15]

Outcome in the eight-patient PGIMER seriesReported finding
Follow-up2 months to 3 years
Upper-tract reflux14/15 anastomoses nonrefluxing[7]
Ureteroileal obstruction or catheterization difficultyNone observed during reported follow-up
Early complicationsTwo intestinal obstructions, three ureteroileal leaks, one vesico-ileocutaneous fistula

The indications were mixed, and one patient had prior radiotherapy for recurrent vaginal cancer. The authors considered the operation feasible, particularly with nonirradiated bowel, while emphasizing early complications and the need for more follow-up.[7]

Marino–Laudi cutaneous T-pouch​

Eighteen patients were followed for a mean of 12 months (range 4–20). All were reported continent by day and night, with no catheterization difficulties, reflux or late complications during that short observation. Evacuation intervals were approximately four hours.[8]

The first five patients had the original orthotopic T-pouch configuration, and the technique was then simplified to use less ileum. The authors used a split-cuff nipple ureteric implantation. Their objective describes the serosa-lined extramural valve with a Mitrofanoff procedure as the continence mechanism.[8]

Seifert cutaneous Double T series​

Seifert reported 19 patients who had a cutaneous ileal Double T pouch between July 1998 and July 2006 (median follow-up 24 months, range 3–76). Sixteen of 19 (84.2%) were continent day and night without catheterization difficulty, counting patients who were continent after reoperation. Mean pouch capacity was 490 mL (range 250–1,100) and mean operating time 580 minutes (range 420–840). Five patients (26.3%) had complications related to the diversion. Renal function stayed stable, and reflux, recurrent pyelonephritis and stones were not found. Three patients with a body mass index above 30 developed necrosis of the efferent loop with pouch-cutaneous fistulas, and the authors did not recommend the Double T pouch in obese patients.[14]

Hemi-T augmentation​

Kurzrock described one 10-year-old boy who required augmentation and a continent channel when the appendix was unavailable. At one year the reservoir was continent, without reflux or infection, and the previously described hydronephrosis had resolved.[9]

A separate 2020 exstrophy report used an appendix, rather than a second ileal T tube, as the catheterizable channel within a serosa-lined tunnel.[10]

Classic Stein–Skinner cutaneous layout​

Stein and Skinner's original cutaneous Double-T description isolates 70 cm of terminal ileum while sparing the distal 15 cm. The proximal 10 cm forms the afferent (antireflux) segment, the distal 15 cm forms the efferent continence limb, and the intervening approximately 45 cm is configured into a W with roughly 11-cm limbs. Mesenteric windows span 3–4 cm for the afferent limb and 7–8 cm for the efferent limb; the afferent segment is tapered over a 30-Fr catheter and the efferent over a 16-Fr catheter, with gradual efferent tapering to avoid a ridge that could impede catheter passage. These dimensions apply only to Stein and Skinner's configuration; PGIMER and Abol-Enein–Ghoneim measurements are separate.[1]

Abol-Enein–Ghoneim serosa-lined extramural (SLET) cutaneous pouch​

Abol-Enein and Ghoneim's serosa-lined extramural tunnel (SLET) technique was reported separately for cutaneous diversion: 109 patients received a continent ileal pouch with two SLET valves (one antireflux, one continent outlet, the appendix used for the outlet in 44). The 109 recipients included 95 adults and 14 children; two died in hospital of pulmonary embolism, and 18 (16.5%) had 22 early complications.[16] Among 93 evaluable patients at mean follow-up of 36.6 months, 88 were continent day and night, the mean catheterization interval was 4–5 hours, and upper tracts were stable or improved in 94.8% of renal units.[16] Late complications affected 11/93 (11.8%; 14 events), including pouch stones, stomal stenosis, inability to catheterize, parastomal hernia and adhesive bowel obstruction.[16] In their ileal-outlet construction, the authors isolate 60 cm of terminal ileum: a 40-cm middle segment forms the W-shaped reservoir, a proximal 10-cm segment forms the afferent antireflux limb, and a distal 10-cm segment forms the catheterizable outlet, with both channel segments tapered over a 22-Fr catheter while the proximal one-third of the inlet is left untapered for ureteral implantation; 3–4 mesenteric windows are made along each channel's vascular arcade (vessel loops as suture guides), and the tunneled segments are embedded in serosa-lined troughs while preserving their blood supply.[17][18] In a later, mixed-age 161-patient Abol-Enein ileal reservoir series, the authors attributed difficult catheterization to outlet angulation and/or reservoir ptosis and advised adequate outlet length and reservoir fixation.[21] In their 2006 operative atlas, Abol-Enein and Ghoneim listed heavily irradiated bowel, previous bowel resection and creatinine clearance <40 mL/min as contraindications to this ileal pouch.[18]

Orthotopic Evidence: What Transfers and What Does Not​

Intermediate orthotopic cohort​

Stein's 209-patient orthotopic cohort had median follow-up of 33 months. Four patients developed afferent T-limb stenosis, three after adjuvant pelvic radiation; 17 developed pouch calculi and nine ureteroileal obstruction.[5]

Outcome in the 209-patient orthotopic seriesReported finding
Patients169 men, 40 women; mean age 69
Perioperative mortality3 (1.4%)
Early complications63 (30%); 10 (5%) diversion-related
Late complications68 (32%); 38 (18%) diversion-related
Most common late diversion-related eventsPouch calculi 17, ureteroileal obstruction 9
Upper tractNormal or decompressed in 162/181 imaged (90%)
Renal function (serum creatinine)Stable or improved in 96%
Complete voiding75%; 25% used intermittent catheterization (20% of men, 43% of women)

The study's 87% daytime and 72% nighttime continence results were among evaluable orthotopic patients. Reflux was seen in 15/158 evaluated reservoirs, and upper tracts were normal or decompressed in 162/181 imaged patients.[5]

USC-STAR randomized trial​

USC-STAR randomized 484 patients to orthotopic T-pouch (237) or Studer (247). There were 423 patients with complete baseline data and 260 with the three-year renal outcome. At three years, mean eGFR decline was 6.6 versus 6.4 mL/min/1.73 m², respectively (p = 0.35); the three-year cumulative incidence of diversion-related secondary surgical reintervention was 22% with T-pouch versus 13% with Studer.[11]

Baseline eGFR, age and urinary tract obstruction, not neobladder type (p = 0.63), were independently associated with 3-year renal decline, and the cumulative risk of urinary tract infection and overall late complications did not differ. The trial was single-center and unmasked. Its findings should inform the inlet's complexity-versus-benefit discussion without discarding the outlet's separate purpose. See the orthotopic T-pouch page for trial details.[11]

Choosing a Continent Cutaneous Reconstruction​

The practical comparison is between complete reconstructions that fit the patient's bowel, ureters, abdominal wall and catheterization ability. An appendix channel is an outlet option, not a standalone substitute for a bowel reservoir. Indiana, Mainz, Kock and Double T reconstructions have different inlet and outlet designs.[12][13]

FeatureDouble TKockIndianaMainz pouch I
Bowel segmentIleum onlyIleum onlyRight colon and terminal ileumCecum and ileum
Inlet (ureteral) mechanismSerosa-lined T-limbIntussuscepted afferent nippleTunneled or direct transcolonic implantation[19]Submucosal or serosa-lined extramural tunnel[20]
Outlet (continence) mechanismSerosa-lined T-limbIntussuscepted efferent nipplePlicated terminal ileum at the ileocecal valveAppendix or intussuscepted ileal nipple; serosa-lined tapered ileum has been described for revision of four modified Mainz pouch I outlets[22]
Intussusception requiredNoYes, both limbsNoOptional

For Double T counseling, explain the small cutaneous evidence base and potential need for revision, alongside the risks of difficult catheterization, stomal or tunnel stenosis, efferent-loop necrosis (reported in obese patients), upper-tract obstruction, stones, infection and metabolic complications.

See Also​

References​

1. Stein JP, Skinner DG. T-mechanism applied to urinary diversion: the orthotopic T-pouch ileal neobladder and cutaneous double-T-pouch ileal reservoir. Tech Urol. 2001;7(3):209–222. PMID:11575518.

2. Stein JP, Skinner DG. "The Craft of Urologic Surgery: The T Pouch." Urol Clin North Am. 2003;30(3):647–61. doi:10.1016/s0094-0143(03)00033-8

3. Stein JP, Lieskovsky G, Ginsberg DA, Bochner BH, Skinner DG. "The T Pouch: An Orthotopic Ileal Neobladder Incorporating a Serosal Lined Ileal Antireflux Technique." J Urol. 1998;159(6):1836–42. doi:10.1016/S0022-5347(01)63170-7

4. Skinner DG, Lieskovsky G, Boyd SD. "Continent Urinary Diversion. A 5 1/2 Year Experience." Ann Surg. 1988;208(3):337–44. doi:10.1097/00000658-198809000-00011

5. Stein JP, Dunn MD, Quek ML, Miranda G, Skinner DG. "The Orthotopic T Pouch Ileal Neobladder: Experience With 209 Patients." J Urol. 2004;172(2):584–7. doi:10.1097/01.ju.0000131651.77048.73

6. Bochner BH, Stein JP, Ginsberg DA, et al. "A Serous Lined Antireflux Valve: In Vivo Fluorourodynamic Evaluation of Antireflux Continence Mechanism." J Urol. 1998;160(1):112–5. doi:10.1016/s0022-5347(01)63049-0

7. Agarwal MM, Mavuduru R, Singh SK, Mandal AK. "Preliminary Short-Term Outcomes of a Modified Double-T Ileal Continent Cutaneous Urinary Diversion Using Yang-Monti Tube Implantation Through Serosa-Lined Extramural Tunnel: The PGIMER Pouch." Urology. 2012;79(4):943–9. doi:10.1016/j.urology.2011.12.026

8. Marino G, Laudi M. "Ileal T-Pouch as a Urinary Continent Cutaneous Diversion: Clinical and Urodynamic Evaluation." BJU Int. 2002;90(1):47–50. doi:10.1046/j.1464-410x.2002.02784.x

9. Kurzrock E, Skinner DG, Stein JP. "Hemi-T Pouch Modification for Pediatric Urinary Diversion." J Urol. 2003;170(3):949–51. doi:10.1097/01.ju.0000080329.28607.bc

10. Abdelhalim A, Soltan MA, Helmy TE, Dawaba ME, Hafez AT. "Ileal Neobladder With a Continent Cutaneous Catheterizable Channel Using the Extramural Serous Lined (Mansoura) Technique in a Bladder Exstrophy Patient." Urology. 2020;146:302. doi:10.1016/j.urology.2020.09.021

11. Skinner EC, Fairey AS, Groshen S, et al. "Randomized Trial of Studer Pouch Versus T-Pouch Orthotopic Ileal Neobladder in Patients With Bladder Cancer." J Urol. 2015;194(2):433–9. doi:10.1016/j.juro.2015.03.101

12. Fisch M, Thüroff JW. "Continent Cutaneous Diversion." BJU Int. 2008;102(9 Pt B):1314–9. doi:10.1111/j.1464-410X.2008.07976.x

13. Pearce SM, Daneshmand S. "Continent Cutaneous Diversion." Urol Clin North Am. 2018;45(1):55–65. doi:10.1016/j.ucl.2017.09.004

14. Seifert HH, Obaje A, Müller-Mattheis V, et al. "Clinical and functional results after continent cutaneous urinary diversion with the ileal double-T-pouch." Urol Int. 2008;80(1):8–12. doi:10.1159/000111722

15. "Continent ileal pouch for urinary diversion: surgical technique (step-by-step) and complications." Urology-Textbook.com. Web resource.

16. Abol-Enein H, Salem M, Mesbah A, et al. "Continent Cutaneous Ileal Pouch Using the Serous Lined Extramural Valves. The Mansoura Experience in More Than 100 Patients." J Urol. 2004;172(2):588-591. doi:10.1097/01.ju.0000129437.33688.4d

17. Abol-Enein H, Ghoneim MA. "Serous Lined Extramural Ileal Valve: A New Continent Urinary Outlet." J Urol. 1999;161(3):786-791. doi:10.1016/s0022-5347(01)61769-5. PMID:10022685

18. Abol-Enein H, Ghoneim MA. "Surgical Atlas: A Continent Cutaneous Ileal Neobladder Using the Serous-Lined Extramural Valves." BJU Int. 2006;98(5):1125–1137. doi:10.1111/j.1464-410X.2006.06467.x

19. Ahlering TE, Weinberg AC, Razor B. "Modified Indiana pouch." J Urol. 1991;145(6):1156–1158. doi:10.1016/S0022-5347(17)38561-0

20. 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

21. Ochcharkhadzhiev SB, Darenkov SP, Abol-Enein H, et al. "Continental cutaneous extramural ileal outlet. 20-year experience. (Multicenter study)." Urologiia. 2024;(6):84–89. doi:10.18565/urology.2024.6.84-89

22. Kälble T, Roth S. "Serosa lined and tapered ileum as primary and secondary continence mechanism for various catheterizable pouches." J Urol. 2008;180(5):2053–2057. doi:10.1016/j.juro.2008.07.052