CASE REPORT
Yang-Monti Principle in Bridging Long Ureteral Defects: Cases Report and A Systemic Review
Jun Sheng Bao#, Qiqi He#, Yuzhuo Li, Wei Shi, Gongjin Wu, Zhongjin Yue*
Keywords: reconstruction; ileal ureteral replacement; long ureteral defect; Yang-Monti Principle.
Ureteric substitution using the Yang-Monti principle was reported as a modification of simple ileal ureter replace-
ment. During April 2013 to June in 2015, 2 patients underwent ileal ureteral substitution using a reconfigured ileal
segment of Yang Monti principle in our clinical center. Some slight modifications were made and then follow-up
were carried out up to 12 months. For these 2 cases, no significant intra/post-operative complications occurred.
In 1 year follow up, serum creatinine (Scr) and blood urea nitrogen (BUN) of both patients decreased to normal.
Glomerular filtration rate (GFR), renogram and pyelogram showed a stable split renal function. To better under-
stand the Yang-Monti principle and potential risks and complications, we conduct an systemic review by searching
PubMed, Google Scholar and the Cochrane Library database from January 1996 through June 2016. 10 out of
644 publications were identified, which included 269 patients from cohort studies. The most usual indications for
Yang-monti therapy were iatrogenic stricture and retroperitoneal fibrosis. Infection and ileus were indicated as the
main short time postoperative complications while the fistula and re-strictures happened in long-term. In general,
we believe Yang-Monti Principle is a safer and efficient technique for clinical partial and complete ureteral defects
if patients and potential risks could be well prepared.
INTRODUCTION
Ureteral loss represents a surgical challenge to provide low pressure drainage while avoiding urinary stasis and reflux. The ideal replacement should optimize drainage while minimizing absorption, allowing for ure-
teral repair of varied lengths and locations with maximal preservation of the urinary tract. Long-segment ureter
defects usually appeared in surgery of severe ureteric obstruction or ureteric stricture, which might be caused by
neoplasms, retroperitoneal fibrosis, iatrogenic injuries during open or endourological surgeries, radiation/chemical
damage and chronic inflammation.
Various techniques have been described in literature to handle such problems posed by a shortened ureter not
amenable to repair by direct re-anastomosis. One modifications is the application of Yang-Monti principle which
allows the creation of a long tube from short bowel segment after its re-configuration.
Department of Urology, Key Laboratory of Disease of Urological System, Gansu Nepho-Urological Clinical Center, Second Hospital
of Lanzhou University, Lanzhou, Gansu, China, 730030
#These two authors contribute equally to the work.
*Correspondence: Department of Urology, Key Laboratory of Disease of Urological System, Gansu Nepho-Urological Clinical Center,
Second Hospital of Lanzhou University, 80 CuiYing RD,ChengGuan District Lanzhou, China ,730000.
E-mail: Yuezhongjin@sina.com.
Received April 2017 & Accepted June 2017
Case Report 4055
Figure1: Antegrade angiography images preoperative and post-
operative a.pre-op (M) b.pre-op (F) c.post-op (M) d.post-op (F).
First coined in 1996 to describe using small bowel for
ureteric replacement got widely acceptance, which was
applied for ureteral replacement first in dogs(1) then
clinically(2) in few case reports. The feasibility of con-
structing a long tube from short segments of ileum was
evaluated clinically(3,4) and experimentally(5). Due to the
excellent functional outcome, the technique was applied
in the clinical setting. However, potential postoperative
risk of urine leakage, peritonitis and urine reflux occur
occasionally , which need to take into account. Moreo-
ver, experiences of Yang-Monti in China/Asia remain
rare. We believe some paucity of modification could fa-
cilitate and thus report our experiences on 2 patients in
our center. Moreover, we performed a systemic review
on the outcome, risks and complications of surgery.
REPORT OF CASES
Two cases were performed during April 2013 to June
in 2015 in our clinical center. Both patients underwent
preoperative evaluation in the form of careful history
taking, medical examination and laboratory investiga-
tions which included complete routine blood tests, urine
analysis, blood renal function, coagulation function,
sodium, potassium, and chloride estimation (Tables 1
and 2). Radiological investigations to visualize the up-
per urinary tract included renal ultrasonography, intra-
venous urography (IVU) or computerized tomographic
urography(CTU). Glomerular Filtration Rate (GFR) /
renal isotope scanning(RIS) were performed to estimate
the split renal function. All patients underwent preoper-
ative colonic preparation for 24 hours. The study was
approved by the ethical committee of Second Hospi-
tal of Lanzhou University (2015A-078). Both patients
were consented for approval of surgery.
Case 1: 75 year-old male
A 75 year-old man presented to us with a chief com-
Yang-Monti principle in ureteral defects-Bao et al.
Case 1 Case 2
Gender Male Female
Age 75 41
Etiology Urothelium carcinoma of solitary kidney Iatrogenic stricture
Locations of defect Right Mid-ureter Left upper-ureter
Length of defect (cm) 22 15
Surgery time(min) 384 302
Hospitalization(d) 23 15
Antibody time(d) 11 7
D-J tube removal(w) 4 6
Table 1. The basic information of two cases
Abbreviation: cm: centimeters, min:minutes, d:days, w:weeks
Case 1:Ureteral Carcinoma (M) Case 2: Ureteral Obstruction (F)
Pre-op Post-op Pre-op Post-op
WBC (×109/L) 8.7 4.32 6.86 7.33
HGB (g/L) 127 106 140 126
HCT(L/L) 0.387 0.335 0.420 0.388
U-RBC (/uL) 3722.5 10-20/HPF 37.4 1-3/HPF
U-WBC (/uL) 301.5 0-2/HPF 1295.3 0-2/HPF
PH (-) 6.5 6.5 6.5 6.0
BUN 84 4.7 6.0 12.3
Scr 1200 67 68 86
Sodium 143.6 138.7 141.7 147.8
Potassium 3.5 3.86 3.9 4.33
Chloride 104.2 112.2 102.5 115.0
Abbreviations: pre-op: preoperative examination, post-op: postperative examination, WBC: white blood cell, HGB: hemoglobin, HCT:
hematocrit, SRF: scrum renal function, Scr: scrum creatinine,
Table 2: Basic Laboratory Findings of Two Cases
Vol 14 No 04 July-August 2017 4056
plaints of for intermittent hematuria lasting for 5-6
weeks and anuria for 1 week. He also had a history of
left nephrectomy 10 years ago. On admission, no co-
morbidities were found, personal and family histories
were negative for previous cancers. A high level of Scr
(1200umol/L) was observed (Table 2) and the non-con-
trast enhanced CTU images delineated an upper right
dilated ureter. Right nephrostomy was performed to de-
crease the creatinine. Antegrade imaging via nephros-
tomy tube demonstrated ureter obstruction located in
the level of the anterior superior iliac spine. (Figure 1)
We thus performed ureterscopic biopsy and pathology
showed low-grade urothelium carcinoma. With these
findings, a diagnosis of urothelium carcinoma was
made. The patient strongly claimed for treatment. Con-
Case Report 4057
sidering his solitary kidney, after all palliative therapy
options discussed, we offered the patient two surgery
choices: 1. keeping nephrostomy tube after radical ure-
teral resection and surveillance; 2. ileal ureteral substi-
tution after radical ureteral resection and surveillance.
The patient finally decided to choose the latter option.
Case 2: 41 year-old female patient
The other case was a 41 year-old female patient referred
for left flank pain and intermittent fever. She had his-
tory of ureteroscopy and lithotripsy for left proximal
ureteral calculus and bladder-musculature flap surgery
due to ureteral stricture 1 year before admission. On
admission, laboratory findings were normal (Table 2).
The non-contrast enhanced CT scan, nephrostomy, an-
tegrade imaging and cystoscopy were performed in se-
quence. The results confirmed left proximal upper tract
ureteral obstruction, combined with hydronephrosis.
The left ureteric orifice was not detected in cystoscop-
ic examination. All treatment options were discussed,
however, we had no choice but to perform ileal ureteral
substitution surgery of Yang-Monti principle owing to
a 15 cm ureter defects of bladder-musculature flap sur-
gery history. (Figure 1)
Surgery technique was basically according to with
previous Yang-Monti principle demonstration(6). The
differences existed in anastomosis. We used malposed
suture method and a non-refluxing Lich-Gregoir tech-
nique to reduce the risk of re-stricture and calculus for-
mation. Malposed suture method focused on non-direct
3m follow-up 6m follow-up 12m follow-up
Case 1: UC (M)
WBC (×109/L) 3.97 5.25 9.18
HGB (g/L) 108 110 92
HCT(L/L) 0.340 0.365 0.378
U-RBC (/uL) 75.7 1-3/HPF 0-2/HPF
U-WBC (/uL) 23.7 0-2/HPF 0-1/HPF
PH (-) 6.5 6.5 6.5
BUN 5.7 6.3 4.8
Scr 170 121 146
Case 2: US (F)
WBC (×109/L) 7.14 6.56 4.23
HGB (g/L) 128 122 118
HCT(L/L) 0.396 0.412 0.384
U-RBC (/uL) 16.4 0/HPF 0/HPF
U-WBC (/uL) 28.2 0-1/HPF 0-1/HPF
PH (-) 6.0 6.5 6.5
BUN 4.6 6.3 5.1
Scr 87 75 78
GFR(ml/min) - L: 24.9, R: 61.1 L: 26.6, R:,73.1
Abbreviations: uc: Ureteral Carcinoma, US: Ureteral Stricture, pre-op: preoperative examination, post-op: postperative examination, m:
months, WBC: white blood cell, HGB: hemoglobin, HCT: hematocrit, SRF: scrum renal function, Scr: scrum creatinine, GFRşGlomer,-
ular filtration rate
Table 3: Follow-up information of Two Cases
Figure2: The malposed suthure of ileal segments ----- suturing line
Yang-Monti principle in ureteral defects-Bao et al.
suture line forming “T-shaped” anastomotic stomas
which generate less suture corners compared to “cross-
shaped” stomas of traditional suture method and de-
crease the potential risks of urine leakage from suture
corners, which might be of benefit for urine leakage
prevention.(Figure 2) At the end of the procedure, ne-
phrostomy tube, double-J stent, drainage tube for ret-
roperitoneal cavity and urethral catheter were inserted.
Postoperative fluid infusion and intermittent bladder
washing were carried out for 2 weeks. Drainage tubes
were removed 2-3 days after operation and double J
tube were maintained for 4-6 wks. Antegrade imag-
ing was performed at 4 weeks after operation which
revealed fluent drainage of ileal ureteral substitutions.
Figure 3: Samples(M) and recunstroction CT(F) of patients.
Author (years) Country Type N Mean Age (Y.O) Followup Post-op Long-term (> 3m) Evidence
patients: time camplications complications level
Ali-el-Dein B(2003)3 Egypt cohort 10 48.7 10/10: 12m Urinary leakage Reflux: 1/10 2c
Urinary tract infection 4/10
B l.Chung(2006)11 UK CC & cohort 52 48.6 52/52: 72m Pyelonephritis: 4/52 Reflux Failure: 3/52 2b
Wound infection: 1/16 Stricture: 2/16
SA. Armatys(2008)10 US cohort 91 46.8 91/91: 36m Infection: 23/91 Fistula: 9/91 2b
Bowel Obstruction: 15/91 Stricture: 7/91
Steffens JA(2010)15 German cohort 18 47.4 18/18: 50m Infection and paralytic Infections & Fistula: 4/18 2b
ileus: 9/18
M.Esmat(2013)6 Egypt cohort 16 35.0 ± 8.0 9/16: 44m Urinary leakage: 1/16 None 2b
Infection: 4/16
Ordorica R(2014)13 U.s cohort 16 45 16/16: 44m None Ureteral Fistula: 1/16 2b
Bilateral Obstruction: 1/16
M.Takeuchi(2014)16 Japan cohort 8 43.6 8/8: 60m Metabolic acidosis: 3/8 Fistula: 2/8 2c
Stricture: 1/8
S.S Nazir(2015)14 India cohort 9 35.0 9/9: 36m Urinary leakage: 1/9 None 2c
Wound infection:1/9
YM Xu(2015)9 China cohort 44 41.0 43/44: 69m Intestinal Obstruction: 2/43 None 2c
Maigaard(2015)7 Danmark cohort 5 47 5/5: 41m Urinary leakage: 3/5 Ureter Stricture: 1/5 2b
Abbreviation: Cc: Case-Control; YO: Years Old; Post-op: Post Operation; m: month
Table 4: Studies Characteristicts of Yang-monti principle and ileal ureteral reconstruction (1996-2016)
Yang-Monti principle in ureteral defects-Bao et al.
Vol 14 No 04 July-August 2017 4058
The hydronephrosis severity of the first case was great-
ly improved. Nephrostomy tubes were removed under
the evidences of no fever or flank pain observed after
tube clamping. (Figures 1 and 3)
We appointed three follow up visits at 3, 6 and 12
months after operation to evaluate the recovery of these
patients. Blood routine tests, urine analysis, blood renal
function, IVU and GFR test were thus performed. The
male patient refused to take radioactive tests while the
female patient accepted all after informed consent.
During follow-up, no urine leakage, obstruction, excess
mucus production, metabolic abnormalities, frequen-
cy, oliguria or odynuria were observed. IVU revealed
fluently drainage in both patients 3 month after opera-
tion. The differential GFR of the female patient for left
and right kidneys were 24.9ml/min and 61.1 ml/min on
6-month follow up and promoted to 26.6ml/min(left)
and,73.1ml/min(right) on 12-month follow up. (Table
3).
SYSTEMIC REVIEW
Search strategy of systemic review
For systemic review, we used the PICOS method ac-
cording to the PRISMA statement (CRD42015019212;
http://www.crd.york.ac.uk/PROSPERO). A search for
articles published from January 1996 through June
2016 using 3 databases, PubMed, Google Scholar,
and the Cochrane Library database was conducted for
potentially eligible studies using a reproducible strat-
egy. The search was limited to 20 years because the
Yang-monti principle firstly applied in dogs starting in
1996. The following separate searches were conducted
using medical subject heading (MeSH) terms to maxi-
mize the search results. The search resulted in 644 ci-
tations. Duplicates and experts reviews were removed.
The laparoscopic/robotic surgery, pediatrics and few
cases report (cases less than 3) were excluded. Studies
with inconsistent/insufficient data or errors, conferenc-
es abstract and unpublished reports were also excluded.
Studies selection
A total of 644 potential relevant abstracts in MEDLINE
(n = 15), Google scholar (n = 629), the Cochrane Li-
brary (n = 0) were examined. 631 were duplicates, un-
related, 1-3 cases report, pediatrics or not original arti-
cles; two papers(7,8) did not mainly focus on Yang-Monti
principle and postoperative complications, one(9) proba-
bly involved the same patients. The remaining 10 publi-
cations(10) published during 2003-2015 were included in
our systemic reviews. (Figure 4)
Studies Characteristics
A total of 269 patients were recruited across all 10 co-
hort studies. Considering the different states of patients
and medical levels, etc. might generate the high heter-
ogeneity, we just demonstrated the clear information
extracted from publications and the vague information
was excluded. Among all 269 cases, 9.67% (26/269)
were from Africa, 27.8%(75/269) were from Europe,
22.68%(61/269) were from Asia and 39.78%(107/269)
were from the U.S. The most usual indication for op-
eration was iatrogenic stricture (approximate 51.46%
ş123/239) and then retroperitoneal fibrosis (approx-
imate 16.73%, 40/239) (data not shown). Regularly,
the antibodies were performed 1-2 weeks and DJ tubes
were dilated for 2-5 weeks. The short time postoper-
ative complications were infections (27.9%, 75/269)
and ileus (9.6%, 26/269). Fistula (4.7%, 12/251) and
strictures (4.1%,11/269) were more probably to appear
after 3 months(Table 4). The approximate percentag-
es we used were not accurate but close to the result of
larger sample research(8, 9) when we performed analysis
respectively.
DISCUSSION
In 1993, Yang was the first to describe two small pre-
viously detubularized ileal segments to develop trans-
verse tube in a patient undergoing radical cystectomy.
The patient remained continent and had no difficulties
Figure 4: Flow Chart of Studies and patients search strategy
Yang-Monti principle in ureteral defects-Bao et al.
Case Report 4059
with catheterization. Unfortunately, the main topic of
publication focused on the investigator’s creation of
an antireflux mechanism needle on the ileal wall but
not the construction technique. There was no refer-
ence to the conception of the new tube in the title or
abstract of the publication. Perhaps this was the rea-
son why the technique continued to be unknown until
1997, when Monti et al. described independently the
detailed construction of single and double ileal tubes in
dogs(1). Yang Monti technique was thus widely recog-
nized and accepted. Other following reports presented
different bowel segments (intestinal or colon) for ure-
teric replacement. The merits of the ileal segment are
its mobility, small diameter, and constant blood supply.
However, common postoperative risks were urine leak-
age, peritonitis, colic, strictures and infections(11,12). In
addition, drawbacks mostly attributed to the absorbing
and secreting characteristics of the involved bowel seg-
ments such as hyperchloremic metabolic acidosis and
excess mucus production and also to the wide caliber
refluxing ileal ureter with subsequent progressive dil-
atation, functional obstruction and recurrent UTI(13,14).
In our two cases, we made slight modifications:(1). We
located ureteric replacement in the retroperitoneum,
which is more accordant to the initial physiological char-
acteristics and can decrease the interference in abdo-
men. In additional, urine leakage or localized infections
associated with postoperative complications might be
much easier to drain out due to cavity space limitation,
which would notably decrease peritonitis, strictures and
infections and benefit for ERAS (Enhanced Recovery
After Surgery).(2). We used a non-antireflux mechanism
in the distal end-to-end anastomosis between bladder
and ureter. Lich-Gregoir methods also generate stric-
tures(15,16), the patients with calculus and stricture his-
tory might be better without antireflux mechanism. In
these two cases, direct anastomosis made our surgery
more simple and less time consuming, and also could
significantly reduce the ureteric ileal segment replace-
ment and ureteral path. The less secretion of succus en-
tericus might be of benefit for maintaining the normal
function, efficient urine drainage and fast recovery of
the newly reconstructed urinary tracts.(3). The malposed
suture method was employed in the ileal segments for
end-to-end anastomosis in these two cases, which might
be efficient to decrease the occurrence of urine leakage
after operation. However, this procedure needs more
evidence.
During follow-up, no complaint of stricture, fistula,
excess mucus production was observed by others(17,18).
These might be an advantage of slight modifications
and most probably due to the marked reduction in the
size of the secreting surface area in comparison with
simple ileal ureters that may be associated with mucous
obstruction in some cases. In addition, hyperchloremic
metabolic acidosis was not observed, which was report-
ed in varying percentages by some studies(14). Absence
of metabolic disorders among our cases might have
contributed to proper surgery timing selecting (serum
creatinine ≤100mmol/L), reduction of the size of ab-
sorbing surface area might decrease the contact of urine
with the ileal mucosa.
Our systemic review, to our knowledge, is the most
comprehensive review on the topic at present. We had
to admit that systemic review of these no-control and
cohort prospective/retrospective studies might have
high heterogeneity due to limited cases, different etiol-
ogies and similar outcomes in literature, which would
generate multiple potential biases. Therefore, extracted
data of these ten publications did not fit for a meta-anal-
ysis. We just presented the publications to show clear
and brief information. We suppose some preventive
measures could be taken into account to prevent some
potential complications, i.e. maintaining temporary uri-
nary diversion through preoperative nephrostomy tube,
postponing removal of double-J tube to 12-24 weeks,
maintaining great blood supply of ileal segments in
surgery and proper antibiotics, which might efficiently
reduce the possible occurrence of short-term infection,
ileus and leakage after surgery as well as fistula and
stricture in a long run.
Nevertheless, although our two patients had different
clinical courses and we were convinced that we provid-
ed them with optimal treatment at that time, long-term
follow-up and more cases are needed, particularly in the
evaluation of non-antiflux influence in certain patients
with similar clinical causes. We believe that wide-
spread of the kind of Yang-Monti principle is necessary
and should be perform in caution. Our work might be
helpful to some urologists who identify or develop new
modification surgery setting and can benefit appropri-
ate patients.
CONCLUSIONS
In general, we believe Yang-Monti Principle is a safer
and efficient technique for clinical partial and complete
ureteral defects if patients and potential risks could be
well prepared. Our cases experiences and review find-
ings might be helpful to some urologists and may ben-
efit proper patients. Multi-center experiences and long-
term follow-up remain necessary in future.
CONFLICT OF INTEREST
The authors declare no conflict of interest.
ACKNOWLEDGMENTS
We apologize to those investigators whose original
work could not be cited owing to the space and search-
ing limitations. The study was supported by grants
(201306180078) from the China Scholarship Council
and the authors thank all the medical staffs participated
in this work.
REFERENCES
1. Monti PR, Lara RC, Dutra MA, de Carvalho
JR. New techniques for construction of
efferent conduits based on the Mitrofanoff
principle. Urology. 1997;49:112-5.
2. Ghoneim MA, Alieldein B. Replacing the
ureter by an ileal tube, using the Yang-Monti
procedure. BJU Int. 2005;95:455-70.
3. Alieldein B, Ghoneim MA. Bridging long
ureteral defects using the Yang-Monti
principle. J Urol. 2003;169:1074-7.
4. Castellan M, Gosalbez R. Ureteral replacement
using the Yang-Monti principle: Long-term
follow-up. Urology. 2006;67:476-9.
5. Tscholl R, Tettamanti F, Zingg E. Ileal
substitute of ureter with reflux-plasty by
Yang-Monti principle in ureteral defects-Bao et al.
Vol 14 No 04 July-August 2017 4060
terminal intussusception of bowel Animal
experiments and clinical experience. Urology.
1977;9:385-9.
6. Esmat M, Abdelaal A, Mostafa D. Application
of Yang-Monti principle in ileal ureter
substitution: is it a beneficial modification?
Int Braz J Urol. 2012;38:779.
7. Wagner M, Bayne A, Daneshmand S.
Application of the Yang-Monti Channel in
Adult Continent Cutaneous Urinary Diversion.
Urology. 2008;72:828-31.
8. Ma L, Liu L, Shen H, Dan D, Wang L, Deng
YH. The perioperative and convalescence
nursing of 5 cases of Monti ileovesicostomy.
International Journal of Clinical &
Experimental Medicine. 2015;8:2887-92.
9. Xu YM, Qian L, Qiao Y, et al. Ileal ureteric
replacement with an ileo-psoas muscle tunnel
antirefluxing technique for the treatment of
long segment ureteric strictures. BJU Int.
2008;102:1452-6.
10. [No authorlisted]. !!! INVALID CITATION
!!!
11. Ali-el-Dein B, Ghoneim MA. Bridging
long ureteral defects using the Yang-Monti
principle. J Urol. 2003;169:1074-7.
12. Ordorica R, Wiegand LR, Webster JC,
Lockhart JL. Ureteral replacement and onlay
repair with reconfigured intestinal segments. J
Urol. 2014;191:1301-6.
13. Verduyckt FJ, Heesakkers JP, Debruyne FM.
Long-term results of ileum interposition for
ureteral obstruction. Eur Urol. 2002;42:181-7.
14. Takeuchi M, Masumori N, Tsukamoto
T. Ureteral Reconstruction With Bowel
Segments: Experience With Eight Patients in
a Single Institute. Korean Journal of Urology.
2014;55:742-9.
15. Baston C, Harza M, Preda A, et al.
Comparative urologic complications
of ureteroneocystostomy in kidney
transplantation: transvesical Leadbetter-
Politano versus extravesical Lich-Gregoir
technique. Paper presented at: Transplantation
proceedings, 2014.
16. Maigaard T, Kirkeby HJ. Yang–Monti
ileal ureter reconstruction. Scand J Urol.
2015;49:313.
17. DeFoor Jr WR, Reddy PP. Minimally
Invasive Techniques to Approach
Complications of Enterocystoplasty and
Continent Catheterizable Channels. Pediatric
Endourology Techniques: Springer; 2014:287-
99.
18. Lopes RI, Dénes FT, Padovani G, Sircili MH,
Srougi M. Monti's principle in the treatment
of congenital uterovesical fistula. Urology.
2014;83:1170-2.
Yang-Monti principle in ureteral defects-Bao et al.
Case Report 4061