Intestinal Segments
Ileum, colon and ileocecal segments provide vascularized tissue for urinary reservoirs, conduits, channels and selected genital reconstruction. Their mesenteric blood supply is preserved. They are not free grafts.
See the overview article for the reference summary: Grafts in GU Reconstruction, and the anatomy article: Bowel Anatomy. Bowel anastomosis technique is covered in Bowel Anastomosis. For segment selection when a prior bowel anastomosis or resection already exists, see Reoperative Bowel Harvest.
Core Principle
Intestinal segments are not free grafts in the strict technical sense; they are vascularized visceral segments isolated on a mesenteric pedicle and repurposed as reservoir, conduit, channel, or lining. They are included in the grafts library because the reconstructive question is the same: which tissue best substitutes for the missing urinary or genital surface?
Bowel retains mucus secretion and absorptive functions after transfer. Detubularization disrupts coordinated contractions and improves reservoir geometry; it does not abolish all intestinal smooth-muscle activity. The choice must account for perfusion, urinary contact time, renal function, previous bowel surgery and lifelong follow-up.[1][2][6] For adults with NLUTD considered for augmentation or a continent catheterizable channel, assess whether the patient or a caregiver can perform regular clean intermittent catheterization.[10]
Ileum
Ileum is widely used for urinary diversion and augmentation. Its suitability depends on actual mesenteric reach and perfusion, the amount and location of bowel remaining, and the planned reservoir or conduit; previous surgery, radiation or bowel disease may change the choice.[8]
| Property | Reconstructive implication |
|---|---|
| Long mesentery and multiple arcades | Potential pelvic reach; confirm a well-perfused segment reaches without mesenteric tension |
| Thin wall and good compliance after detubularization | Useful for low-pressure reservoirs |
| Mucus production | Requires irrigation education in catheterized reservoirs |
| Terminal ileum absorbs B12 and bile salts | Preserve functioning distal ileum when possible; document the harvested segment and arrange B12 follow-up |
Applications
- Ileocystoplasty and broader augmentation cystoplasty
- Orthotopic neobladder families such as Hautmann neobladder and modified Studer pouch
- Ileal conduit
- Ileal ureter and Yang-Monti ileal ureter
- Yang-Monti catheterizable channel
Sigmoid Colon
Sigmoid colon offers a larger caliber and a pedicle supplied through the inferior mesenteric system. It can provide a urinary segment or a mucus-secreting vaginal substitute. Both ileal and colonic urinary segments can cause hyperchloremic metabolic acidosis; severity also depends on exposed surface area, contact time and renal reserve.[1][2][6]
| Property | Reconstructive implication |
|---|---|
| Larger caliber and thicker wall | Useful for reservoirs and neovagina, but can be bulky in a narrow pelvis |
| IMA / sigmoid-artery pedicle | Requires attention to marginal artery and rectosigmoid watershed perfusion |
| Persistent mucus production | Plan reservoir irrigation or neovaginal secretion care according to the reconstruction |
| Intestinal electrolyte exchange during urine contact | Monitor for hyperchloremic metabolic acidosis |
Applications
- Sigmoid cystoplasty
- Sigmoid neovagina / bowel vaginoplasty when skin-graft or peritoneal options are unsuitable. Gender-affirming intestinal vaginoplasty series report stenosis, mucorrhea and prolapse; diversion colitis, anastomotic bowel leak and intra-abdominal abscess can present years later and require prompt evaluation.[11]
- Colon conduit or colon shuffle when ileum is unusable
Ileocecal Segment
The ileocecal segment combines terminal ileum, cecum, appendix, and right-colon territory. Its special value is that the ileocecal valve and appendix can be incorporated into continent cutaneous systems, while the right colon supplies reservoir capacity.[1][4]
| Component | Reconstructive role |
|---|---|
| Cecum / right colon | Reservoir wall for continent cutaneous diversion or augmentation |
| Terminal ileum | Catheterizable limb, efferent limb, or reconfigured channel |
| Ileocecal valve | Part of the continence mechanism at the catheterizable outlet in an Indiana-type reservoir; not itself a ureteric antireflux mechanism |
| Appendix | Natural small-caliber catheterizable channel when present and usable |
Applications
- Ileocecal cystoplasty
- Indiana pouch
- Appendicovesicostomy / Mitrofanoff: an appendix-based channel can be harvested without transferring the whole ileocecal segment
- Ileocecal continent cutaneous diversion families, including Mainz / right-colon variants
Mesenteric Perfusion and Watershed Points
Segment viability depends on preserving arcade perfusion during harvest and anastomosis.
- Small-bowel mesenteric clearance. Clear no more than about 8 cm of mesentery from the end of a small-bowel segment to preserve marginal perfusion and reduce the risk of ischemic necrosis at the staple or suture line.[8]
- Colonic watershed points. Griffiths' point near the splenic flexure lies between middle-colic and ascending-left-colic collateral territories; Sudeck's point at the rectosigmoid junction lies between the last sigmoid branch and superior rectal artery. The cited textbook advises placing anastomoses to either side of these landmarks when feasible, particularly when perfusion is threatened by hypotension or arterial interruption. The cited vascular review reports that Sudeck-point anastomoses are common without ischemic problems, while Griffiths' point warrants particular attention after left-colic or inferior-mesenteric-artery ligation. Confirm perfusion at the proposed margin; neither landmark is an absolute contraindication.[8][9]
Metabolic Complications
Long-term follow-up should assess renal function, electrolyte and acid-base disturbances, emptying, stones, symptomatic infection and, after cystectomy with bowel urinary diversion, ureteroenteric stricture.[6] For adults with NLUTD after bowel-segment lower-tract reconstruction, AUA/SUFU advises annual focused history, examination and symptom assessment, basic metabolic panel, and urinary-tract imaging .[10] After augmentation, counsel about reservoir perforation.[10] For patients with bowel urinary diversion after cystectomy, the EAU bladder cancer guideline states that vitamin B12 should be measured annually after cystectomy with bowel diversion (guideline text, not a graded recommendation); augmentation and other reconstructions need follow-up matched to the segment and underlying condition.[5][6]
| Issue | Most relevant segments | Practical response |
|---|---|---|
| Hyperchloremic metabolic acidosis | Ileum and colon | Monitor bicarbonate / chloride; treat with oral alkali when clinically significant |
| Mucus production | Intestinal reservoirs and channels | Teach irrigation for catheterized reservoirs; evaluate stones and recurrent blockage |
| Vitamin B12 deficiency | Terminal ileum | Preserve terminal ileum when possible; monitor and supplement B12 |
| Bile-salt malabsorption | Terminal ileum | Watch for diarrhea and fat-soluble vitamin issues after longer resections |
| Stones and chronic bacteriuria | Reservoirs and catheterizable systems | Hydration, complete emptying and mucus management; treat symptomatic infection, not colonization alone |
| Late malignancy | Augmented bladders and bowel reservoirs | For adults with NLUTD after bowel lower-tract reconstruction, perform cystoscopy for gross hematuria or symptomatic recurrent UTI ; investigate suprapubic pain or other concerning new symptoms, and use reconstruction-specific surveillance without a blanket annual cystoscopy rule.[10] |
Patients with reconstructed lower urinary tracts commonly have asymptomatic bacteriuria. The EAU strongly recommends against screening or treating asymptomatic bacteriuria in patients with reconstructed lower urinary tracts, so a bowel segment alone does not prompt routine screening; pregnancy and urinary procedures breaching the mucosa require separate assessment.[7] Mucus has been implicated as a stone nidus. Khoury compared mucus from 8 stone-forming and 10 non-stone-forming augmentation patients and found higher calcium-to-phosphate ratios in the mucus of stone formers; the study did not test an irrigation regimen.[3]
For the dedicated management pages, see Renal Function & Metabolic Surveillance, Mucus Management, Vitamin B12 Supplementation, and Urinary Acidifiers & Alkalinizers.
References
1. Santucci NR, Velez A. "Physiology of Lower Gastrointestinal Tract." Aliment Pharmacol Ther. 2024;60 Suppl 1:S1-S19. doi:10.1111/apt.17900
2. Kiela PR, Ghishan FK. "Physiology of Intestinal Absorption and Secretion." Best Pract Res Clin Gastroenterol. 2016;30(2):145-159. doi:10.1016/j.bpg.2016.02.007
3. Khoury AE, Salomon M, Doche R, et al. "Stone formation after augmentation cystoplasty: the role of intestinal mucus." J Urol. 1997;158(3 Pt 2):1133-1137. doi:10.1016/s0022-5347(01)64404-5. PMID 9258156
4. Rowland RG, Mitchell ME, Bihrle R, Kahnoski RJ, Piser JE. "Indiana continent urinary reservoir." J Urol. 1987;137(6):1136-1139. doi:10.1016/S0022-5347(17)44428-4
5. Stabler SP. "Vitamin B12 Deficiency." N Engl J Med. 2013;368(2):149-160. doi:10.1056/NEJMcp1113996
6. European Association of Urology. Muscle-invasive and Metastatic Bladder Cancer, 2026. Follow-up of functional outcomes and complications. Guideline.
7. European Association of Urology. Urological Infections, 2026. Asymptomatic bacteriuria in reconstructed lower urinary tracts and before urinary procedures. Guideline.
8. Preston MA, Dahl DM. Use of Intestinal Segments in Urinary Diversion. In: Partin AW, Dmochowski RR, Kavoussi LR, Peters CA, eds. Campbell-Walsh-Wein Urology. 13th ed. Elsevier; 2025:2784-2811.
9. Sakorafas GH, Zouros E, Peros G. "Applied vascular anatomy of the colon and rectum: clinical implications for the surgical oncologist." Surg Oncol. 2006;15(4):243-55. doi:10.1016/j.suronc.2007.03.002
10. American Urological Association/Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction. Neurogenic Lower Urinary Tract Dysfunction: AUA/SUFU Guideline. 2021. Guideline
11. Robinson IS, Cripps CN, Bluebond-Langner R, Zhao LC. "Operative management of complications following intestinal vaginoplasty: A case series and systematic review." Urology. 2023;180:105-112. doi:10.1016/j.urology.2023.07.005