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Yang-Monti Ileal Ureter

The Yang-Monti ileal ureter detubularizes short ileal segments and retubularizes them transversely into a narrow conduit. The original series used 5–7.5 cm of ileum, while a seven-patient whole-ureter series used five or six 2.5-cm segments. In the largest series, the median defect length was 11 cm (range 8–16).[1][11][5] 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 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 burdenThe original series used 5–7.5 cm for a 12–18 cm substitute; a seven-patient whole-ureter series generally used five or six 2.5-cm segments (12.5–15 cm of ileum).[1][2][4][11]
Wide caliber requires taperingRetubularized tube has near-ureteral diameter; tapering not required.[1]
Large mucosal surface → mucus obstructionThe smaller urine-exposed mucosal area is intended to reduce mucus production.[1][4][2]
Hyperchloremic metabolic acidosisSmaller absorptive surface. No metabolic complications were reported 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 a Boari flap or psoas hitch.[2]

Indications​

The Yang-Monti ileal ureter is used when ureteroureterostomy, a Boari flap with psoas hitch, transureteroureterostomy, or a suitable oral-mucosal or appendiceal repair cannot bridge the defect or has failed.[2][13] In a 2026 systematic review, oral-mucosal grafts were used mostly for strictures <5 cm and appendiceal techniques for defects up to 7.5 cm; heterogeneous studies precluded meta-analysis.[13] In the 36-patient Yang-Monti series, defects measured 8–16 cm.[5]

EtiologyFrequency / notes
Iatrogenic stricturesMost common; 16/36 (44%) in the largest series.[5]
Bilharzial (schistosomal) strictures[1]
Tuberculous strictures[1]
Retroperitoneal fibrosis[5]
Radiation stricturesReported in a seven-patient Yang-Monti total-replacement series and a separate conventional ileal-ureter cohort.[11][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. For long-segment ureteral injury, the 2026 EAU trauma guideline says to avoid intestinal interposition in patients with impaired renal function or known intestinal disease; in a 36-patient Yang-Monti series, Ali-El-Dein et al. proposed eGFR <40 mL/min/1.73 m² as a relative contraindication.[14][5]
  • Preoperative mapping and function. A seven-patient Yang-Monti total-replacement series included serum creatinine and split renal function in its preoperative assessment and placed nephrostomy tubes before reconstruction in all seven patients; a 46-patient conventional ileal-ureter series used simultaneous antegrade and retrograde urograms to define stricture length and location.[11][6]
  • Selected patients with CKD or a solitary kidney had favorable results, but 4 of 36 patients experienced renal-function deterioration.[5]
  • Bowel suitability. Prior extensive bowel resection, inflammatory bowel disease, or severe radiation enteritis may make ileal harvest unsuitable; these were contraindications or relative contraindications in a conventional ileal-ureter cohort and require assessment before Yang-Monti reconstruction.[6]
  • Bladder storage before ileovesical implantation. Assess capacity and compliance when impairment is suspected.[6] Severe bladder dysfunction was a relative contraindication in one 46-patient conventional ileal-ureter cohort.[6]

Surgical Technique​

Open and laparoscopic Yang-Monti ileal ureter reconstruction have been reported.[1][4][7]

  1. Bowel isolation. Match the ileal harvest to the defect: the original series used 5–7.5 cm, whereas a seven-patient total-ureter series used five or six 2.5-cm segments. Preserve the terminal ileum and ileocecal valve where possible and retain the mesenteric pedicle. Restore bowel continuity; a later four-case series used a stapled side-to-side anastomosis.[1][11][10]
  2. Subdivision. The original series divided the harvest into two (double Monti) or three (triple Monti) equal parts. Whole-ureter replacement has used five or six 2.5-cm segments; choose segment count for the required conduit length.[1][11]
  3. Detubularization. The original series incised each segment along a paramesenteric line; a later four-case series described an antimesenteric incision. Specify the chosen construction while preserving the segmental vascular pedicle.[1][10]
  4. Reconfiguration. Lay the opened segments side by side and suture them into a continuous flat strip.
  5. Retubularization. Tubularize the strip over a sizing catheter to form the neoureter. In a four-case report, the double- and triple-Monti operative figures show a 16 Fr Foley catheter for this step.[10]
  6. Proximal anastomosis. Anastomose the neoureter to a spatulated proximal ureteral stump when available. A renal pelvic opening can be used for ileopyelostomy in total replacement; ureterocalicostomy has been described for selected UPJ-level defects.[10][11]
  7. Distal anastomosis. Anastomose to a usable distal ureteral stump or implant into the bladder when the distal ureter is unavailable. The original series used a submucosal tunnel for bladder implantation; a later series also described a split-cuff bladder implant. Select the route according to reach, bladder characteristics, and obstruction risk.[1][10]
  8. Stenting. Internal ureteral stenting is used, with removal timed to the repair. In a seven-patient total-replacement series, the authors inserted two JJ stents into the ileal tube and generally retained them for more than 6 weeks, or more than 8 weeks after radiotherapy; antegrade pyelography confirmed patency after stent removal and before nephrostomy removal.[11]
  9. Leak check and drainage. A four-case series tested the completed urinary anastomoses with instillation through the bladder and nephrostomy and placed an operative drain; a seven-patient total-replacement series used pelvic drainage to detect urinary or enteric leakage.[10][11]
  10. Orientation. Transverse retubularization changes the native bowel axis; route the neoureter dependently without tension, kinking, or mesenteric torsion while preserving the segmental blood supply.[10][2]

Variations​

  • Onlay technique. When the native ureteral plate is preserved, the reconfigured strip is used as an onlay rather than full circumferential replacement, which preserves native ureteral tissue.[4]
  • Segment-by-segment assembly. A four-case series described retubularizing separate 2–3 cm ileal segments over a Foley catheter and joining the tubes end to end for multi-segment repairs.[10]
  • Double Monti with sigmoid colon. Has been described for total ureteral substitution combined with a Boari flap.[3]

Antireflux Considerations​

The narrow caliber permits submucosal-tunnel reimplantation. Reflux occurred in 1/10 patients in the original series after a mean 9.6 months of follow-up (range 6–13 months).[1] A separate conventional ileal-ureter series discusses antireflux implantation into intestinal reservoirs. Nipple-valve use is not mandatory for every Yang-Monti repair; balance reflux, reservoir pressure and anastomotic obstruction risk.[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)[5]
Intestinal obstruction2.8% (1/36)[5]
Perioperative complicationsClavien-Dindo grades 1–2 only
Reflux (with submucosal reimplant)~10% (1/10) historically[1]
Renal deterioration4/36 patients; renal-function change is distinct from a defined patency endpoint[5]

Overall renal function improved, including in selected CKD and solitary-kidney subgroups; 4 patients with stage 3 CKD deteriorated. CKD subgroup labels are inconsistent within the published abstract, which limits any stage-by-stage safety rule.[5] Follow renal function and imaging for obstruction after reconstruction. No metabolic complications were reported in the 36-patient Yang-Monti series, while hyperchloremic metabolic acidosis occurred in 4/108 patients in a separate conventional ileal-ureter cohort; monitor serum electrolytes and bicarbonate without treating that rate as Yang-Monti-specific.[5][9]

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.[1][2][3][5][6][9]

Complications​

  • Urinary tract infection. About 28%, the most common complication.[5]
  • Bowel obstruction and ileus. Intestinal obstruction occurred in 1/36 in the dedicated long-term series; postoperative or delayed ileus occurred in 2/7 after Yang-Monti total-ureter replacement.[5][11] A separate conventional ileal-ureter cohort reported an 8.3% small-bowel-obstruction rate.[5][11][9]
  • Anastomotic stricture. In a seven-patient Yang-Monti total-replacement series, 1/7 developed proximal ileal-pelvic stenosis requiring reanastomosis at 11 months; in a separate five-patient complete-substitution series, 1/5 required permanent double-J stenting for stricture at mean 41-month follow-up.[11][12] A conventional ileal-ureter cohort reported anastomotic stricture in 4/108 patients (3.7%).[9]
  • Urinary leak or fistula. In a five-patient Yang-Monti complete-substitution series, 3/5 had immediate proximal anastomotic leakage requiring drainage, prolonged stenting, or nephrostomy.[12] A separate mixed reconfigured-intestine series reported one fistula in an irradiated patient (of 13).[4]
  • Mucus obstruction. The smaller urine-exposed mucosal area is intended to reduce a recognized complication of intestinal ureteral substitution; no mucus obstruction was reported among seven Yang-Monti total-replacement patients at median 36.7-month follow-up.[2][11]
  • Renal-function deterioration. 4/36 (11%) in the dedicated series, all with stage 3 CKD.[5] The 36-patient Yang-Monti series reported renal deterioration in 4/36.[5] In conventional ileal-ureter analyses from one institution, an earlier 108-patient cohort found a 3.7-fold bilateral-repair association, whereas a later 158-patient cohort found no significant association.[9][15]

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

10. Önal B, Gültekin MH, Kalender G, et al. "Use of Yang-Monti Procedures for Ureteral Defect Repair in Different Clinical Cases: A Case Series." J Urol Surg. 2024;11(2):124–128. doi:10.4274/jus.galenos.2023.2023-6-1

11. Lin CW, Chen JC, Huang WJ, Lin TP. "Whole ureter replacement with Yang-Monti principle: successful treatment of challenging conditions." BMC Urol. 2022;22(1):198. doi:10.1186/s12894-022-01150-0

12. Maigaard T, Kirkeby HJ. "Yang-Monti ileal ureter reconstruction." Scand J Urol. 2015;49(4):313–318. doi:10.3109/21681805.2014.882980

13. Ditonno F, Costantino S, Treccani LP, et al. "Autologous Tissue Substitutes for Ureteral Reconstruction: A Systematic Review of Surgical Techniques and Outcomes." Eur Urol Open Sci. 2026;86:30–41. doi:10.1016/j.euros.2026.02.007

14. Waterloos M, Campos Juanatey F, Hallscheidt P, et al. EAU Guidelines on Urological Trauma. EAU Guidelines Office, Arnhem, Netherlands; 2026. Section 4.2.4.b.2.c. ISBN 978-94-92671-32-5. Guideline

15. Soyster ME, Burns RT, Slaven JE, et al. "Long-term Renal Preservation and Complication Profile With Ileal Ureter Creation." Urology. 2024;188:138–143. doi:10.1016/j.urology.2024.04.025