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Endourologic Management of an Iatrogenic Ureteral Avulsion Using a Thermoexpandable Nickel–Titanium Alloy Stent (Memokath 051)

Authors:
Maral Rouhani at Royal National Throat, Nose and Ear Hospital, London
Maral Rouhani
  • Royal National Throat, Nose and Ear Hospital, London
Hamid Abboudi at Imperial College Healthcare NHS Trust
Hamid Abboudi
Norma Gibbons
Norma Gibbons
Norma Gibbons
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Tamer El-Husseiny at Imperial College Healthcare NHS Trust
Tamer El-Husseiny
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Abstract and Figures

Background: The use of ureteroscopy in the management of urolithiasis is well established. Ureteral avulsion is a rare but challenging complication of the procedure. Postureteral injury strictures are a common result of such injuries and are typically managed with reconstructive surgery or endoscopically with polymer stent. This case represents the first effective management of ureteral avulsion and subsequent ureteral stricture using a Memokath ureteral stent. Case Presentation: A 54-year-old gentleman presented to the Department of Urology with right loin pain as a result of right renal calculi, previously treated with extracorporeal shockwave lithotripsy. The patient was investigated with ultrasonography and noncontrast CT of his urinary tract, revealing mild right-sided hydroureteronephrosis and two right proximal ureteral stones, measuring 9 and 4 mm, respectively. He underwent a right semirigid ureteroscopy and laser stone fragmentation with complete stone clearance, but on withdrawal of the ureteroscope, a right ureteral injury occurred with ureteral mucosal avulsion extending from the L3/L4 vertebrae to the right vesicoureteral junction. Upon consideration of several options for management of this ureteral avulsion, the patient opted for endourologic stenting. After 10 months, the patient developed a ureteral stricture as a result of the avulsion. He was troubled with stent-related symptoms and wanted to avoid reconstructive surgery and, therefore, opted for a Memokath ureteral stent. The patient recovered well with excellent renal function and drainage on subsequent mercaptoacetyl-triglycyl renogram. Conclusion: Ureteral avulsion is a rare but important complication of ureteroscopy with numerous options available for management. Discussions should be had with the patient to weigh the various options, and metallic stents should be considered in the long-term management of such injuries and their sequel.
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Case Report
Endourologic Management of an Iatrogenic Ureteral
Avulsion Using a Thermoexpandable Nickel–Titanium
Alloy Stent (Memokath 051)
Maral J. Rouhani, MRCS, Hamid Abboudi, MRCS, Norma Gibbons, FRCS MD,
and Tamer El-Husseiny, FRCS MD
Abstract
Background: The use of ureteroscopy in the management of urolithiasis is well established. Ureteral avulsion is a
rare but challenging complication of the procedure. Postureteral injury strictures are a common resultof such injuries
and are typically managed with reconstructive surgery orendoscopically with polymer stent. This case represents the
first effective management of ureteral avulsion and subsequent ureteral stricture using a Memokath ureteral stent.
Case Presentation: A 54-year-old gentleman presented to the Department of Urology with right loin pain as a
result of right renal calculi, previously treated with extracorporeal shockwave lithotripsy. The patient was
investigated with ultrasonography and noncontrast CT of his urinary tract, revealing mild right-sided hydro-
ureteronephrosis and two right proximal ureteral stones, measuring 9 and 4 mm, respectively. He underwent a
right semirigid ureteroscopy and laser stone fragmentation with complete stone clearance, but on withdrawal of
the ureteroscope, a right ureteral injury occurred with ureteral mucosal avulsion extending from the L3/L4
vertebrae to the right vesicoureteral junction. Upon consideration of several options for management of this
ureteral avulsion, the patient opted for endourologic stenting. After 10 months, the patient developed a ureteral
stricture as a result of the avulsion. He was troubled with stent-related symptoms and wanted to avoid re-
constructive surgery and, therefore, opted for a Memokath ureteral stent. The patient recovered well with excellent
renal function and drainage on subsequent mercaptoacetyl-triglycyl renogram.
Conclusion: Ureteral avulsion is a rare but important complication of ureteroscopy with numerous options
available for management. Discussions should be had with the patient to weigh the various options, and metallic
stents should be considered in the long-term management of such injuries and their sequel.
Keywords: ureteral injury, ureteroscopy, stent
Introduction
Urolithiasis is a common urologic presentation, and
intervention using ureteroscopy has become one of the
main modalities of management. Ureteral avulsion is a rec-
ognized but rare complication of ureteroscopy. We present a
case of management of ureteral avulsion using a Memokath
ureteral stent.
Case Report
A 54-year-old gentleman presented to our specialized
stone clinic in October 2015 with right loin pain, on a back-
ground of previous extracorporeal shockwave lithotripsy for
right renal stones. His medical history also included hyper-
tension and hypercholesterolemia. Ultrasonography of his
urinary tract revealed mild right-sided hydronephrosis and a
subsequent noncontrast CT confirmed the presence of two
right proximal ureteral stones, measuring 9 and 4 mm, re-
spectively, with associated mild hydroureteronephrosis.
He underwent a right semirigid ureteroscopy and laser
stone fragmentation with complete stone clearance. On
withdrawal of the ureteroscope at the end of the procedure, a
right ureteral injury occurred with ureteral mucosal avul-
sion extending from the level L3/L4 vertebrae to the right
Department of Urology, Charing Cross Hospital, London, United Kingdom.
ªMaral Rouhani et al. 2017; Published by Mary Ann Liebert, Inc. This is an Open Access article distributed under the terms of the
Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original
work is properly cited. Mary Ann Liebert, Inc. offers reprint services for those who want to order professionally produced copies of articles
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JOURNAL OF ENDOUROLOGY CASE REPORTS
Volume 3.1, 2017
Mary Ann Liebert, Inc.
Pp. 57–60
DOI: 10.1089/cren.2017.0019
57
vesicoureteral junction. Ureteroscopic-guided attempts at
insertion of a guidewire could not breach the entire ureteral
defect; therefore, a 6F 26 cm ureteral stent was inserted to
ensure that the ureteral lumen is preserved because the ureter
was completely avulsed with no overlying mucosa (Fig. 1).
An urgent nephrostomy was inserted by the interventional
radiologist after an urgent CT urogram (Fig. 2).
Several management options were urgently considered in a
multidisciplinary team approach, including urologic sur-
geons, renal transplant surgeons, and interventional radiolo-
gists. Options included endoscopic management, ureteral
reconstruction by either a Boari flap or an ileal interposition,
autotransplantation, transureteroureterostomy, and finally
even consideration of a nephrectomy.
The patient and his family opted for endoscopic manage-
ment, so on day 1 postoperatively, a combined antegrade/
retrograde endoscopic repair (rendezvous procedure) was
performed effectively, with insertion of an 8F 26 cm right-
sided ureteral stent to bridge the segment of the avulsed ureter
(Fig. 3). He recovered well postoperatively with normalized
blood tests and good urine output. He was discharged on day
5 after the initial ureteroscopy with a nephrostomy and ure-
thral catheter both on free drainage. He attended for a weekly
consultant urologist outpatient review.
A nephrostogram was performed 3 weeks later that showed
satisfactory passage of contrast from the renal pelvis to the
bladder with no evidence of ureteral leak. The nephrostomy
was clamped and the urinary catheter was subsequently re-
moved. A dimercaptosuccinic acid (DMSA) nuclear medi-
cine scan was also performed at 3 weeks, which showed
homogeneous distribution of tracer throughout both kidneys,
at 44% for the right kidney and 56% for the left kidney.
At week 6, further retrograde and antegrade studies were
performed along with a right semirigid ureteroscopy, which
showed a long stricture from the level of L3 to the vesi-
coureteral junction. The stent was replaced effectively with a
6F 26 cm ureteral stent and the right nephrostomy was re-
moved. The patient remained well and was seen again 3
months later for another right retrograde study and uretero-
scopy. The ureteral stricture was again noted from the level of
L3 down to the level of vesicoureteral junction. As such,
balloon endodilatation was performed followed by insertion
of an 8F 26 cm stent. The patient was persistently troubled by
stent-related symptoms, in particular, urinary frequency, ur-
gency, and hematuria. A further DMSA scan 6 months after
the original injury showed normal split function with no
significant change from the previous study.
Given the stricture recurrence, the option of reconstructive
surgery for management of the right ureteral stricture was
rediscussed further, but the patient opted for endourologic
management, namely a semipermanent Memokath ureteral
stent to bridge the length of the stricture. At 10 months after
FIG. 1. Retrograde study con-
firming disruption to the course of
the ureter with inability to place a
guidewire into the kidney (A).A
Double-J polymeric stent was in-
serted to preserve the patency of
the mid and distal ureter (B).
FIG. 2. Contrast CT show-
ing right ureteral disruption
with retroperitoneal contrast
extravasation (white arrow).
The proximal ureteral stent is
seen within the retro-
peritoneum (red arrow).
Rouhani, et al.;Journal of Endourology Case Reports 2017, 3.1
http://online.liebertpub.com/doi/10.1089/cren.2017.0019
58
the original injury, a special-order 20 cm dual cone Memo-
kath was effectively inserted (Fig. 4). The patient has made
good recovery and has been reporting less stent-related
symptoms and a better quality of life than when using the
standard Double-J stents.
A mercaptoacetyl-triglycyl (MAG3) renogram 14 months
postoperatively on the December 13, 2016, showed no ob-
struction to drainage, with the right kidney contributing to
46% function (Fig. 4).
Discussion
This is the first reported case of the use of a Memokath
stent in the management of a ureteral stricture secondary to
iatrogenic ureteral avulsion. Ureteral avulsion is a rare but
serious complication of ureteroscopy, the incidence of which
has been reported as 0%–3.75%.
1
The urologist is faced with
a number of management options in such a situation, ranging
from stenting to open reconstruction. Such a situation also
poses a challenge in communication with the patient. It is
vital that a frank discussion takes place with the patient,
explaining that the entire renal unit is potentially at stake, yet
there are a number of management options; the decision
should then be made jointly between patient and surgeon.
The management of iatrogenic ureteral avulsion depends
greatly on the site and severity of injury. For proximal in-
juries, end-to-end anastomosis can be considered; Boari flap
and Psoas hitch are options for middle-third ureteral avulsion.
For severe injuries, including total ureteral avulsion from
both ends, options include ureteral implantation using an ileal
interposition, renal autotransplantation, and nephrectomy.
Each management option has benefits and drawbacks, and so
must be tailored for suitability to the patient.
With regard to open reconstructive ureteral injury repairs,
conventional teaching dictates a delayed approach to allow
inflammation and extravasation to subside. However, in the en-
doscopic setting, an early attempt at realignment of the ureteral
ends is often utilized to capitalize on the naivety of the tissue
injury, exploiting the patency of the ureteral ends before the
process of scaring and fibrosis of the ureter setting in.
FIG. 3. Nephrostogram identify-
ing the Double-J stent outside the
course of the ureter (A) (arrow).
Followed by effective rendezvous
insertion of a Double-J polymeric
stent across the ureteral defect (B).
FIG. 4. Right ureteral Memokath stent bridging the strictured 4 cm segment of ureter that extends from the level of L4/L5
down to the level of the upper sacroiliac joint (A). A MAG 3 renogram with normal appearance and drainage of both
kidneys. No evidence of obstruction seen (B).
Rouhani, et al.;Journal of Endourology Case Reports 2017, 3.1
http://online.liebertpub.com/doi/10.1089/cren.2017.0019
59
Double-J polymeric stents have been traditionally used to
overcome strictures resulting from an avulsed ureter; how-
ever, they are associated with numerous problems: encrus-
tation (necessitating 3–6 monthly stent changes), stone
formation, pain, infection, and reflux. The use of metallic
stents over long-term Double-J stents has progressed over the
past 20 years, with an additional advantage of likely longer
term patency because of resilience of compression; a wide
variety of stents are now available. The Memokath 051 stent
is a thermoexpandable titanium–nickel spiral shaped stent,
2
with available lengths of 3, 6, 10, and 15 cm, and patency
rates from 90% to 100%. It has been shown to have favorable
outcomes in overcoming benign ureteral strictures, as first
reported by Arya et al.
3
; more recently in 2014, Bourdoumis
et al.
4
effectively used the Memokath stent in treating ob-
struction secondary to retroperitoneal fibrosis.
We have shown that the Memokath 051 stent can be used
effectively in treating ureteral stricture secondary to iatro-
genic ureteral avulsion and it should be considered a viable
option when considering the various management options.
Disclosure Statement
PNN has provided funding towards the journal’s publica-
tion fee. No other disclosures.
References
1. Al-Awadi K, Kehinde EO, Al-Hunayan A, et al. Iatrogenic
ureteric injuries: Incidence, aetiological factors and the ef-
fect of early management on subsequent outcome. Int Urol
Nephrol 2005;37:235–241.
2. Klarskov P, Nordling J, Nielsen JB. Experience with
Memokath 051 ureteral stent. Scand J Urol Nephrol 2005;39:
169–172.
3. Arya M, Mostafid H, Patel HR, et al. The self-expanding
metallic ureteric stent in the long-term management of be-
nign ureteric strictures. BJU Int 2001;88:339–342.
4. Bourdoumis A, Kachrilas S, Kapoor S, et al. The use of a
thermoexpandable metal alloy stent in the minimally inva-
sive management of retroperitoneal fibrosis: A single center
experience from the United Kingdom. J Endourol 2014;28:
96–99.
Address correspondence to:
Tamer El-Husseiny, FRCS MD
Department of Urology
Charing Cross Hospital
London W6 8RF
United Kingdom
E-mail: tamer.el-husseiny@imperial.nhs.uk
Abbreviations Used
CT ¼computed tomography
DMSA ¼dimercaptosuccinic acid
Cite this article as: Rouhani MJ, Abboudi H, Gibbons
N, El-Husseiny T (2017) Endourologic management of
an iatrogenic ureteral avulsion using a thermoexpandable
nickel–titanium alloy stent (Memokath 051), Journal of
Endourology Case Reports 3:1, 57–60, DOI: 10.1089/
cren.2017.0019.
Rouhani, et al.;Journal of Endourology Case Reports 2017, 3.1
http://online.liebertpub.com/doi/10.1089/cren.2017.0019
60
... Primary open approach was used in the majority of cases (38/43) with laparoscopic assistance used in 3 cases [7,8]. Endoscopic approach in the form of retrograde and antegrade realignment was used primarily for 4 patients [9][10][11]. Primary nephrectomy was done in seven patients [3,4,8,12,13]. ...
... Though this procedure looked tempting as it can be done immediately and easily, our analysis shows that this temptation should be avoided as the long-term results are not good due to the poor vascularity of the avulsed ureter, which ultimately fibrosed and, if not detected early, leads to silent loss of the renal unit. Endoscopic management in the form of antegrade and retrograde realignment of distracted segments has been described in literature; however, as we have already mentioned, the concern continues to be vascularity which depends on the extent of displacement of the avulsed segments [9][10][11]. These patients have to be followed up rigorously for development of strictures and may require secondary reconstructive procedure for salvaging renal function [9][10][11]. ...
... Endoscopic management in the form of antegrade and retrograde realignment of distracted segments has been described in literature; however, as we have already mentioned, the concern continues to be vascularity which depends on the extent of displacement of the avulsed segments [9][10][11]. These patients have to be followed up rigorously for development of strictures and may require secondary reconstructive procedure for salvaging renal function [9][10][11]. Finally, nephrectomy is also an immediate option where the function of concerned kidney is already deranged and sometimes as a last resort following failed reconstructions especially in older patients. ...
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... However, mucosal avulsion is new terminology which could managed endoscopically. 4 Herein, we present a woman with mucosal ureteral avulsion during transurethral lithotripsy, which the ureteroscope was covered with 5 centimeters of ureteral mucosa. ...
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Article
  • Feb 2005
The Memokath 051 is a thermo-expandable titanium-nickel spiral developed for long-term ureteral stenting. The aim of this study was to investigate the drainage and safety aspects of this stent. A total of 3-4 consecutive patients were included: 22 had benign strictures, five had post-irradiation strictures and seven had malignant strictures. Follow-up visits took place after 1 month and thereafter every 3 months for at least 1 year. Thirty-three patients had a total of 37 stents inserted uni- or bilaterally. Pre-insertion dilatation was impossible in one patient and difficult in two, all of whom had post-irradiation strictures. Insertion was complicated in seven patients and uneventful in the other 26. Fifteen stents were in place and functioning with no discomfort or complications at death or the end of follow-up (median 14 months; range 3-30 months), while 22 were non-functioning after 1 day to 16 months (median 5 months). Of these 22 stents, 10 had migrated and 12 were malfunctioning. Among the latter, stricture length was underestimated in four patients, and the stents were replaced successfully shortly after insertion. Four stents were occluded by stones after 1-10 months. No tissue ingrowth was seen. Stent removal was easy, with the exception of one patient with stent calcification. The Memokath 051 is an alternative for selected patients with non-curable ureteral obstruction but is not suitable for use in patients with functional stenosis or stone formation. Insertion and removal are easy in most patients, but can be difficult or impossible, especially in patients with post-irradiation strictures and retroperitoneal fibrosis. Migration and obstruction can occur and careful follow-up is necessary.
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Iatrogenic Ureteric Injuries: Incidence, Aetiological Factors and the Effect of Early Management on Subsequent Outcome
Article
  • Feb 2005
To investigate the changing pattern in incidence, aetiological factors and the effect of early diagnosis and surgical treatment on the outcome of iatrogenic ureteric injuries in our Urology Unit over a 5 year period. All patients with ureteric injuries caused as a result of any surgical procedures (iatrogenic ureteric injuries) were studied during a 5 year period (1998-2002). Data collected and analysed included yearly incidence of injury, aetiological factors, modalities of treatment and the outcome of management of the injuries. During the study period, our general surgical colleagues had a policy of requesting "J" stent insertion prior to major abdominopelvic surgical procedures. During the same period, in nearly all difficult cases of ureteroscopy (URS) + lithoclast lithotripsy+/-Dormia basket, a ureteric catheter or "J" stent was prophylactically inserted by urological surgeons. There were 82 iatrogenic ureteric injuries in 75 patients over the 5 year period. The total number of iatrogenic ureteric injuries declined from 26 (31.7%) in 1998 to 10 (11.8%) in 2002. Urological, obstetrics and gynaecological and general surgical procedures were involved in 69(84.1%), 7(8.7%), and 4(4.9%) of the injuries respectively. The commonest types of injuries encountered were; injury to ureteric mucosa post URS or lithoclast calculi disintegration 34 (41.5%), complete ureteric perforation 15 (18.3%) and false passage 15 (18.3%). The most severe complications encountered were complete ureteric avulsions 3 (3.75%) and loss of ureteral segment 2 (2.4%). The commonest treatment options used were "J" stent insertion or ureteric catheter placement (48, 59.4%), percutaneous nephrostomy (17, 20.7%), laparotomy and removal of suture on tied ureters (5, 6.1%). Two (2.4%) nephrectomies were performed because of poor renal function in one patient and severe damage to a functioning renal unit during a difficult retroperitoneal surgery in another patient. Recognition and treatment of ureteric injuries at the time of surgery was associated with less morbidity compared to those in whom the diagnosis was delayed. The overall successful resolution of ureteric injuries in this series was 77/82 (93.9%). There was no mortality attributable to these ureteric injuries. In our Unit, the incidence of significant iatrogenic ureteric injuries has shown a decline over a 5-year period. We attribute this trend to the prophylactic use of "J" stents or ureteric catheter placement and good surgical technique during major abdomino-pelvic surgeries in our hospital. Endourological procedures are the commonest causes of ureteric injuries. Prompt diagnosis and institution of appropriate corrective surgical procedures often result in a very satisfactory outcome in about 94% of cases.
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