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Yang-Monti Ileal Ureter

The Yang-Monti ileal ureter uses a short segment of ileum (5–7.5 cm) detubularized and retubularized transversely to create a narrow-caliber conduit suitable for bridging long ureteral defects (8–18 cm). The reconfiguration trades bowel diameter for length, designed to reduce several drawbacks of the classic ileal ureter: excessive mucosal surface area, mucus burden, metabolic absorption, and the difficulty of fashioning a nonrefluxing reimplant from a wide bowel tube.[1][2]

Related: see Yang-Monti Channel for the catheterizable-channel application of the same retubularization principle.

Lineage​

The Yang-Monti retubularization principle is also used for continent catheterizable channels. Ali-el-Dein and Ghoneim reported its use to bridge long ureteral defects in 2003.[1] The core principle:

  1. Isolate a short ileal segment (5–7.5 cm) on its mesentery.
  2. Subdivide the segment into 2 or 3 equal parts.
  3. Open each sub-segment longitudinally along a paramesenteric line, preserving the vascular pedicle.
  4. Unfold and lay the opened segments side by side as a flat ileal strip 12–18 cm long.
  5. Retubularize the strip transversely over a stent into a narrow tube of approximately ureteral caliber.[1][3]

Design Rationale​

Drawback of classic ileal ureterHow Yang-Monti addresses it
Long bowel harvest (15–25 cm) → metabolic / nutritional burden5–7.5 cm suffices.[1][2][4]
Wide caliber requires taperingRetubularized tube has near-ureteral diameter; tapering not required.[1]
Large mucosal surface → mucus obstructionSmaller mucosal area → less mucus.[1][4]
Hyperchloremic metabolic acidosisSmaller absorptive surface — no metabolic complications in the largest long-term series.[5]
More difficult nonrefluxing reimplantNarrow caliber permits submucosal-tunnel ileovesicostomy.[1]
Bowel length limits combinabilityShort segment combines well with Boari flap or psoas hitch.[2]

Indications​

For long ureteral defects (8–16 cm) when simpler reconstructive options (ureteroureterostomy, Boari flap with psoas hitch, transureteroureterostomy) are insufficient or have failed.[5][2]

EtiologyFrequency / notes
Iatrogenic stricturesMost common — ~44% of cases.[5]
Bilharzial (schistosomal) strictures[1]
Tuberculous strictures[1]
Retroperitoneal fibrosis[5]
Radiation strictures[6]
Traumatic ureteral injury (incl. gunshot)[5]
Malignancy-related ureteral loss[5]
Failed prior pyeloplasty or reimplantParticularly pediatric.[7]

Patient Selection and Contraindications​

  • Renal reserve. Ali-El-Dein et al. proposed eGFR below 40 mL/min/1.73 m² as a relative contraindication. This is a cohort-derived selection recommendation, not a universally validated safety threshold.[5]
  • Selected patients with CKD or a solitary kidney had favorable results, but 4 of 36 patients experienced renal-function deterioration. Avoid declaring an entire CKD stage safe on this evidence.[5]
  • Prior bowel surgery or radiation enteritis may limit usable ileum.

Surgical Technique​

Open, laparoscopic, or robotic.[7][4]

  1. Bowel isolation. A 5–7.5 cm segment of healthy ileum is isolated, preserving the terminal ileum and ileocecal valve where possible; the segment remains on its mesenteric pedicle; restore bowel continuity with an end-to-end anastomosis.[1]
  2. Subdivision. Divide the isolated segment into 2 equal parts (double Monti) or 3 parts (triple Monti), depending on required length.[1]
  3. Detubularization. Open each sub-segment along a paramesenteric line, as described in the original ureteral reconstruction series; do not treat paramesenteric and antimesenteric as synonyms.[1]
  4. Reconfiguration. Lay the opened segments side by side and suture them into a continuous flat strip.
  5. Retubularization. Tubularize the strip over a stent / catheter (typically 8–10 Fr) into a narrow tube.
  6. Proximal anastomosis. Spatulated end-to-end anastomosis to the renal pelvis or proximal ureteral stump.
  7. Distal reimplantation. A submucosal tunnel was used in the original series; choose the anastomosis according to bladder characteristics, reach and the risk of obstruction.[1]
  8. Stenting. Internal ureteral stent for 4–6 weeks.
  9. Orientation. Ensure a dependent, tension-free course without mesenteric torsion. Transverse retubularization changes the native bowel axis; it should not be described as maintaining ordinary isoperistaltic bowel orientation.

Variations​

  • Onlay technique. When the native ureteral plate is preserved, the reconfigured strip is used as an onlay rather than full circumferential replacement — preserving native ureteral tissue.[4]
  • Double Monti with sigmoid colon. Has been described for total ureteral substitution combined with a Boari flap.[3]

Antireflux Considerations​

The narrow caliber is the structural reason submucosal-tunnel reimplantation is feasible — reflux occurred in only 1/10 patients in the original series.[1] A separate conventional ileal-ureter series discusses antireflux implantation into intestinal reservoirs. This should not be generalized into a mandatory nipple valve for every Yang-Monti repair; balance reflux, reservoir pressure and the risk of anastomotic obstruction.[8][2]

Long-Term Outcomes​

Largest dedicated Yang-Monti series — Ali-El-Dein 2021, n = 36, median follow-up 68 months (range 12–215):[5]

ParameterResult
Renal functionSignificant improvement in serum creatinine, split renographic clearance, and eGFR
HydronephrosisImproved in most patients on MR urography
Metabolic complicationsNone reported
UTI28% (10/36)
Intestinal obstruction2.8% (1/36)
Perioperative complicationsClavien-Dindo grades 1–2 only
Reflux (with submucosal reimplant)~10% (1/10) historically[1]
Renal deterioration4/36 patients; renal-function change is not interchangeable with a defined patency endpoint[5]

Overall renal function improved, including in selected CKD and solitary-kidney subgroups; 4 patients with stage 3 CKD deteriorated. The abstract contains inconsistent CKD subgroup labels, so it does not support a precise stage-by-stage safety rule.[5]

Pediatric Application​

Laparoscopic Yang-Monti ureteral reconstruction was reported in 6 children (mean age 8.5 yr, mean defect 5.83 cm), most after failed pyeloplasty. All patients showed improvement of differential renal function without obstruction on diuretic renography; mean OR time 314 min, mean blood loss 25 mL. The series also reported 2 grade III complications requiring stent replacement, in addition to grade I–II events.[7]

Comparison With Conventional Ileal Ureter​

Yang-Monti reconstruction uses a shorter bowel harvest and a narrower tube, at the cost of additional bowel suture lines. Published series are small and differ from conventional ileal-ureter cohorts in selection, anatomy and follow-up. They do not demonstrate superior patency, lower bowel morbidity or absence of metabolic risk in a direct comparison.[1][2][3][5][6][9]

Complications​

  • Urinary tract infection ~28% — most common.[5]
  • Small-bowel obstruction 1/36 in the dedicated long-term series; the 8.3% rate in a separate conventional ileal-ureter cohort is not a direct comparison.[5][9]
  • Anastomotic stricture — a recognized risk requiring surveillance; 3.7% was reported in a separate conventional ileal-ureter cohort, not a Yang-Monti estimate.[9]
  • Ureteral fistula — reported in irradiated patients.[4]
  • Mucus obstruction — rare due to reduced mucosal surface.[2]
  • Renal-function deterioration — 4/36 (11%) in the dedicated series, all with stage 3 CKD. The reported 3.7-fold association with bilateral reconstruction comes from a different conventional ileal-ureter cohort and is not a Yang-Monti-specific estimate.[5][9]

See Also​

Videos​

Yang-Monti Ileal Ureter Reconstruction
UroinUa (2021)
Laparoscopic Yang-Monti Ileal Ureter / Boari Flap for a Completely Avulsed Ureter
Dr. Markos Karavitakis (2024)

References​

1. Ali-el-Dein B, Ghoneim MA. Bridging long ureteral defects using the Yang-Monti principle. J Urol. 2003;169(3):1074–1077. doi:10.1097/01.ju.0000050151.66653.cc

2. Xiong S, Zhu W, Li X, et al. Intestinal interposition for complex ureteral reconstruction: a comprehensive review. Int J Urol. 2020;27(5):377–386. doi:10.1111/iju.14222

3. Castellan M, Gosalbez R. Ureteral replacement using the Yang-Monti principle: long-term follow-up. Urology. 2006;67(3):476–479. doi:10.1016/j.urology.2005.09.005

4. Ordorica R, Wiegand LR, Webster JC, Lockhart JL. Ureteral replacement and onlay repair with reconfigured intestinal segments. J Urol. 2014;191(5):1301–1306. doi:10.1016/j.juro.2013.11.027

5. Ali-El-Dein B, El-Hefnawy AS, D'Elia G, et al. Long-term outcome of Yang-Monti ileal replacement of the ureter: a technique suitable for mild, moderate loss of kidney function and solitary kidney. Urology. 2021;152:153–159. doi:10.1016/j.urology.2020.09.061

6. Launer BM, Redger KD, Koslov DS, et al. Long-term follow up of ileal ureteral replacement for complex ureteral strictures: single institution study. Urology. 2021;157:257–262. doi:10.1016/j.urology.2021.07.012

7. Liu D, Zhou H, Hao X, et al. Laparoscopic Yang-Monti ureteral reconstruction in children. Urology. 2018;118:177–182. doi:10.1016/j.urology.2018.04.034

8. Kocot A, Kalogirou C, Vergho D, Riedmiller H. Long-term results of ileal ureteric replacement: a 25-year single-centre experience. BJU Int. 2017;120(2):273–279. doi:10.1111/bju.13825

9. Roth JD, Monn MF, Szymanski KM, Bihrle R, Mellon MJ. Ureteral reconstruction with ileum: long-term follow-up of renal function. Urology. 2017;104:225–229. doi:10.1016/j.urology.2017.02.026