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megaureter.pptx
1. Megaureter and prune- belly
syndrome
Workye Tigabie ,PSR IV
Moderator : Dr. Woubedel, Assistant Professor
of Surgery
Consultant General &Pediatrics Surgeon
3. Normal anatomy and
physiology
The function of the ureter
active pacemaker and latent
pacemaker
Histology of the ureter
Normal length and size of the ureter
6/14/2023 3
4. Definition
Is not a specific disease condition
Refers to abnormal ureteral diilation
>7mm
contribute to 10% to 23% of antenatally
detected upper urinary tract dilatations
other synonyms in use include
megaloureter, wide ureter and
hydroureter
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5. Incidence
Exact incidence is not known
Sporadic occurance
Common in males
Predilection to left side
Bilaterallity is common in 25 % of cases
In unilateral problem contralateral absent or dysplasia
is common
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6. classification
Smith classified megaureters
into 3 categories
obstructed, refluxing,
refluxing with obstruction,
and non-refluxing/non-
obstructing
King also added the 4th type
later subdivided into
primary and secondary by
King.
The Pfistere Hendren
classification based on the
morphological appearance:
type I involved the distal
ureter without associated
hydronephrosis;
type II extended to both
ureter and pelvis
type III was associated with
severe
hydroureteronephrosis and
ureteric tortuosity
6/14/2023 6
8. Classification cont”d
Primary: representing a condition
intrinsic to the ureters itself
secondary: a reaction of the ureters
to a process elsewhere.
to bladder pathologic processes,
such as neurogenic bladder
dysfunction, bladder outlet
obstruction, and/or infection.
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10. Primary obstructive
megaureter
Primary megaureter (POM)
refers to a congenitally wide ureter in
which there is no anatomic narrowing .
Classicaly the site of physiologic
obstruction is near the bladder
(juxtavesical) in 90 to 95 per cent of
ureters and averages 1.5 cm. in
length.
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11. Pathology/pathophysiology
3 hypothesis explain this
Muscle deficiency
Muscle arrangement
abnormalities in the interstitial cells of Cajal
a functional obstruction that is unable to transport
urine at acceptable rates
True stenos is is rarely noted
Why the distal ureter??
6/14/2023 11
12. Pathophysiology cont”d
Reflexing
caused by a short or absent intravesical
ureter
Abnormal collagen deposition
Prune belly syndrome
Megacysttis megaureter association
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13. Pathophysiology cont”d
Non reflexing non obstructive
Most PM fall in this category
transitional renal physiology
increased compliance of the fetal ureter
Spontaneously improved obstruction
Prune belly syndrome
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14. Pathophysiology cont”d
Reflexing and obstructive
Results from ectopic insertion of the ureteral
orifice in the region of the bladder neck.
During bladder filling, the bladder neck is closed,
acting as a distal obstruction.
With voiding, the bladder neck opens and allows
for reflux.
A cyclic voiding cystourethrogram may be
required
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17. Natural course
Reliable predictors of the natural history of
megaureter have not yet been determined
Spontaneous resoultion<10mm
Complicated>10 mm
type III megaureters had the lowest rate of
spontaneous resolution
Persistence of dilatation warrants close
follow up
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18. Management
Therapeutic intervention of the
megaureter is dependent on accurate
classification.
Secondary causes of a megaureter
justify treatment of the primary problem
Existing controversies
Aim of RX
Preserve renal function
prevent infection
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19. Management cont”d
Watchful therpay :
medical Rx and proph abs.
Temporary operative; a septic child
with an obstructed infected system
not responsive to intravenous
antibiotics
Nephrestomy
Pyelostomy
Dilatation and Stenting
Reflexing reimplantation; “dangerous”
obstruction is converted into the
“lesser evil” Of VUR
ureterostomy
Definitive reconstruction
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20. Mgt cont”d
Definative surgery
Repair of the infant megaureter is technically
feasible but remains a challenge even in
experienced hands.
Secondary operative procedures have been
reported as high as 10% when correcting an
obstructed megaureter in an infant <8 months of
age.
It is best to delay the initial urge to repair a
megaureter until the child is older than 12
months of age.
6/14/2023 20
21. Management cont”d
Surgical indications
symptomatic or have recurring UTIs,
progressive unremitting dilatation on
ultrasound,
differential renal function less than
40%, and/or significant decreases in
differential renal function of 5% or
greater on sequential “comparable” renal
nuclear functional studies
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22. Management cont”d
Principles
Resection of the
distal ureter
Straightening and
tapering the ureter
The ureter is tapered
to achieve a ureteral
diameter that will
allow for a 4–5:1
ratio of tunnel length
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24. Management cont”d
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In plication techniques the
blood supply to the ureter is
preserved
Folding techniques, are
suitable only for the moderately
dilated ureter (<1.75 cm in
diameter. Where excision is
required
A diameter that is too large will
result in a bulky remodeled ureter
that is difficult to reimplant.
Our practice!
25. postop
Removal of the ureteral stent is dependent on the procedure
performed.
The stent can be removed 3–7 days after imbrication, and 7–
14 days following an excisional repair. 4 weeks for DJ stent
Ureterograms at the time of stent removal are not necessarily
beneficial.
Postoperative edema can limit drainage, giving the
appearance of a high-grade obstruction
Administration of a broadspectrum antibiotic prior to removing
a stent decreases the possibility of urosepsis even when the
child has been maintained on prophylactic antibiotic
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26. Postop
Postoperative ureteral edema can persist for
6 weeks.
Imaging studies, either sonography or renal
scintigraphy, should be avoided during that
time
A postoperative voiding cystourethrogram at
6 months is performed to confirm the
absence of vesicoureteral reflux.
Prophylactic antibiotics can be discontinued
with resolution of the reflux
6/14/2023 26
27. outcome
Successful operative outcome of megaureter
reconstruction has been reported to be 93–95% for
imbrication, 74–90% for excisional Tapering.
Postoperative complications are not simply due to
technical error;
Increased collagen deposition and altered smooth
muscle may be the etiology for a higher rate of
persisting vesicoureteral reflux following repair
Physician patience is prudent to allow for the operative
edema to subside, which might take 2–3 months.
Persistent obstruction is probably the result of ureteral
ischemia and will ultimately require revision.
6/14/2023 27
29. Introduction
Epidemology
Embryology
Clinical features
Spectrum of the disease
Evaluation and management
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30. Introduction
A constellation of anomalies which is classically defined
by .
Three characteristic findings:
1. a deficiency of abdominal musculature,
2. bilateral intra-abdominal testes, and
3. an anomalous urinary tract.
associated anomalies are common finding with
variable severity
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31. History
Frolich(1839) first described the
characteristic abdominal wall in PBS.
Parker(1895) described the full triad of
anomalies.
William Osler(1901) is credited with giving
the syndrome its name ‘prune belly’ .
Eagle and Barrett reviewed the detail xtics
6/14/2023 31
32. History cont”d
Strumme (1903)Proposed obstructive hypothesis of
prune belly syndrome
Nunn and Stephens (1961)Proposed theory of
mesodermal arrest as an etiology of prune belly
syndrome
the most widely accepted appellation is PBS
Also known as:Eagle-Barrett syndrome ,Triad
syndrome,, and Abdominal musculation syndrome,
mesenchymal dysplasia syndrome
pseudoprune’ is to define females and males who donot
have the complete triad of prune belly syndrome
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33. Epidemology
Incidence: 1 in 29,000 to 1 in 40,000 live births.
50 % whites ,30% black and 20 % hispanics
95%cases in males.
5% cases are females
Higher incidence noted in twins, blacks, and children born to
younger mothers.
Maternal cocaine abuse has associateion.
Incidence declining in developed countries
6/14/2023 33
34. Etiology and embryologic base
Most cases are sporadic with normal
karyotype.
Autosomal dominant, x linked,autosomal
recessive
inheritance have also been reported and
polygenic transmission
Specific chromosomal abnormalitie and
syndromes are rare.
Trisomy 18 ,trisomy 21 Turner syndrome
and Beckwith Wiedemann syndrome
have been demonstrated 6/14/2023 34
35. Etiology cont”d
There is no clear
etiology .
accepted Four main
theories:
(1) Early in utero
posterior urethral
obstruction.
2) Primary defect in
lateral plate
mesoderm
(3) A yolk sac defect.
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37. Presentation and spectrum of the
disease
Woodard’s classification, three major
categories
to segregate the patients
prognostically.
provides a framework for a more
rational approach to overall
management
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39. Adult Presentation
Incomplete forms of PBS- present into
adulthood.
Symptoms of renal failure and
hypertension
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40. CLINICAL FEATURES
GENITOURINARY ANOMALIES:
Kidneys:
Spectrum of anomalies range from
normal renal parenchyma to dysplasia.
Dysplasiai n 50%.
Non-obstructive hydronephrosis.
Primary or secondary UPJO
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41. Clinical feature cont”d
renal dysplasia
Prognosis is directly
related to renal
function and the
degree of renal
dysplasia.
The most severe degree
of renal dysplasia is
recognized from
autopsy studies and
associated with both
Potter’s type II and IV
renal cystic change
Hydronephrosis.
renal function may be
normal
The degree of
hydronephrosis may
not correlate with the
ureteral dilatation or
the abdominal wall
deficiency
repeated UTI is the
feature
l
6/14/2023 41
42. Clinical features cont”d
Ureters:
Dilated, tortuous & redundant.
Muscle fibers are replaced by collagen and
CT.
Distal ureters more severely affected.
Vesicoureteral reflux(VUR) in 85% pts.
The conventional system of grading reflux is
difficult to apply
UPJ & UVJ obstruction- uncommon
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43. Clinical feature cont”d
Ineffective ureteral peristalsis because
of poor ureteral wall coaptation.
Severity of urinary tract abnormalities
is not proportional to flaccidity of
abdominal wall.
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44. Clinical feature cont”d
Bladder:
Massively enlarged,compliant
Diverticula is not feature
except Urachal
pseudodiverticulum.
Patent urachus in 25-30%.
Despite being very thick, bladder
wall is smooth.
Increased ratio of collagen to
muscle fibers in the absence
of obstruction.Delayed first
sensation to void and a large
capacity.
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45. Clinical feature cont”d
A significant postvoid residual volume
Despite these limitations, 50% of PBS
patients void spontaneously with normal
voiding pressures, normal flow rates, and
low postvoid residuals.
Trigone is splayed with ureteric orifices
displaced laterally and superiorly
Poorly defined bladder neck
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46. Clinical feature cont”d
Posterior Urethra :
Posterior urethral dilatation, type 4
valve- angulation of urethra during
voiding.
Various obstructive lesions of distal
posterior urethra
urethral atresia, valves, urethral
stenosis, urethral membrane, and
urethral diverticulum- occur in 20% of
6/14/2023 46
47. Clinical feature cont”d
Anterior urethra:
Most common anomalies: urethral atresia or hypoplasia and
megalourethra.
Bulbous urethral dilatation was evident in 68% of patients with
prune belly syndrome
Unless associated with a patent urachus, urethral atresia is
lethal.
Spontaneous bladder rupture with fistula formation also may
occur.
In PBS, two types of megalourethra seen.
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48. Fusiform type: Scaphoid variety:
a deficiency of corpus
cavernosum +
spongiosum.
Entire phallus dilates with
voiding.
results from a
mesenchymal deficiency
of urethral folds.
The commonest and less
severe form
a deficiency of spongiosum
only with preservation of
glans and corpora
cavernosa.
Ventral urethra dilates with
voiding.
results from a
mesenchymal deficiency of
urethral supportive tissue
6/14/2023 48
50. Clinical feature cont”d
Prostate and Accessory Sex Organs:
prostatic hypoplasia
Vas deferens and seminal vesicles are
atretic;
Epididymis may be poorly attached to the
testis
Lack of continuity between efferent ductules
and rete testis.
Retrograde ejaculation because of an
incompetent bladder neck.
6/14/2023 50
51. Clinical feature cont”d
Testes:
Bilateral intra-abdominal
testes lying over iliac
vessels and adjacent to
dilated ureters- most typical
findings.
There is epididymal
abnormalities
The gubernaculum is
normally attached
increased risk of malignant
degeneration of 30–50
times that of a normally
descended testes .
6/14/2023 51
52. Clinical feature cont”d
Infertility:
Factors contributed are
open bladder neck and poorly developed prostate result in retrograde
ejaculation
Associated abnormalities of the prostatic epithelium and seminal vesicles
Vas deferens obstruction and epididymal abnormalities
testicular histologic abnormalities, with abnormal spermatogenesis
No PBS pts.have fathered a child.
More recently, paternity achieved by sperm retrieval techniques and
intracytoplasmic sperm injection(ICSI).
Normal pregnancy with assisted vaginal delivery- described in a female
PBS patient.
6/14/2023 52
53. Clinical feature cont”d
Abdominal wall defect:
Most characteristic feature in newborn- appearance of
abdominal wall.
uneven involvement, medial and inferior musculature
most deficient.
The order of severity of involvement transversus
abdominis, rectus abdominus below the umbilicus,
internal oblique, external oblique, and rectus abdominis
above the umbilicus
Totally absent abdominal wall musculature occurs
rarely.
6/14/2023 53
54. Clinical feature cont”d
Its impact
unable to sit up: delays standing and
walking
Ineffective coughing causing respiratory
infections
Ineffective defecation causing
constipation
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58. EVALUATION &
MANAGEMENT
Requires a team consisting of a neonatologist, a nephrologist, and a urologist.
Major initial concern is that of management of cardiac and respiratory
issues- do CXR.
BUN,creat,electrolytes - assess renal insuff, met. acidosis.
S.Creat <0.7 % predictive of adeq.renal function.
VCUG- assess Bladder emptying, outlet( esp. in renal insuff)
DTPA/MAG3to assess outflow obstruction in massive HN & stasis(4-6
weeks of age).
6/14/2023 58
59. Management”cont”d
SURGICAL MANAGEMENT
Three components:
Urinary tract
reconstruction:for category
2
Abdominal wall
reconstruction, and
Orchidopexy
Depends on the category of
the disease
Watchfultherapy
Circumcision is advisable-
reduce risk of infant urinary
tract infections.
Prophylactic antibiotic
therapy is recommended-
before VCUG.
for catagory 3 disease
6/14/2023 59
60. Mangement cont”d
Overall goal
to preserve renal fun and prevent infection
definative surgery delayed until the infant is 3 months of age or
more.
If renal insufficiency is severe or infection is initially present,a period
of urinary diversion
Temporary meaures can be taken
cutaneous vesicostomy
Cutaneous ureterostomies
Cut. Pyeloplasty/nephrestomy
6/14/2023 60
61. internal urethrotomy is indicated :
In patients with an anatomic urethral
obstruction, type 4 valve.
A transurethral incision at the 12 o’clock
position has been advised to improve
voiding and decrease residual urine.
Anterior Urethral Reconstruction:
Management”cont”d
6/14/2023 61
62. Management”cont”d
Comprehensive reconstruction
reduction cystoplasty ,resection of the
distal ureter, and bilateral ureteral
tapered reimplantation .
combined with the performance of the
abdominoplasty and bilateral
orchidopexy
This approach is preferably done prior to
1 year of age .
6/14/2023 62
64. Reduction Cystoplasty:
Remodeling into a more spherical
shape to better direct the contractible
forces.
Simple excision of urachal
diverticulum or excision of redundant
mucosa with overlaping flaps.
Management”cont”d
6/14/2023 64
65. Management”cont”d
Orchidopexy:
Timing of orchidopexy- early: to preserve
normal hormonal function.
Transabdominal Orchidopexy- at 6 months
current approach of choice.
If adequate mobilisation not possible -
Fowler-Stephens orchidopexy(Single or multi-
staged)
Microvascular autotransplantation.
6/14/2023 65
66. Management”cont”d
Reconstruction of Abdominal Wall:
Mild degree- may show improvement with
age.
Benefits- improved bladder emptying, more
effective cough and improvement in
defecation.
Timing - can be combined with other urinary
tract reconstructions, even at 6 months.
6/14/2023 66
67. Management”cont”d
Techniques:
Randolph Technique- Transverse
incision from 12th rib to pubic
symphysis to opposite 12th rib
fullthickness removal of skin,
lower abdominal musculature,
and peritoneum.
Healthy fascia is then
approximated to anterior iliac
spines, pubic tubercle, and
inferior fascia.
Disadv.- Lateral abdominal
bulge persists.
6/14/2023 67
68. Management”cont”d
Ehrlich Technique-• Vertical
midline incision,
preservation of umbilicus
on a vascular pedicle from
inferior epigastric artery.
Skin and subcutaneous
tissues are elevated off the
muscle and fascial layers
an overlapping, vest-over-
pants advancement of
each side to contralateral
flank is performed,
preserving the less affected
lateral muscles and fascia.
6/14/2023 68
69. Management cont”d
Monfort Technique-• An elliptically oriented
incision isolates the redundant skin,
extending from the tip of xiphoid to pubis.
A second incision is made around umbilicus
to preserve it in situ.
Skin and subcutaneous tissue are dissected
off the attenuated fascia and muscle with
dissection extending laterally to anterior
axillary line.
Vertical fascial incisions lateral to sup
epigastric a
6/14/2023 69
is to transport urine from the kidney to the bladder by the mechanism of coordinated propagation of muscular contraction (peristalsis) arising in the pelvis and carried distally.
the upper limit of the range of normal ureteral diameters in children up to 16 years of age is 0.50 to 0.65 mm.
Summary of the classfn
provide a larger reservoir and hence a lower pressure buffering system than with dilatation caused by PUJ obstruction
twofold increase in the ratio of collagen fibers to smoothmuscle fibers in the refluxing megaureter compared with the obstructed megaureter and controlureter
This is believed to result from the disruption of urothelial microvasculature because of distention or calculi.
morpholo
influenced by the urologist’s attitude or the family’s preference and compliance to extended follow-up
The ureter is approached
through a 2 cm incision placed within an ipsilateral
low inguinal skin crease. The muscles are separated
and the space of Retzius entered
depending on the clinical presntn,complications ,renal condition
tapering be gradual so
as not to cause an abrupt change in ureteral caliber, which may
cause a form of obstruction.
inherent ureteral characteristics and bladder dysfunction affect a successful outcome.
prune+: irregular skin wrnikling Single most important determinant of long-term survival-
severity of the urinary tract anomaly, in particular, degree of renal dysplasia.
named for the mass of wrinkled skin that is often (but not always) present on the abdomen of those with the disorder
PBS females exhibit abdominal wall deficiency and urinary tract dysmorphism without any gonadal anomaly
resulting in severe dilation of urinary tract and possible fetal ascites and oligohydramnios
(precursor of ureters, bladder, prostate, urethra, and gubernaculum).
Severe degree of renal collecting system dilatation- characteristic.
Calyceal morpoology well-preserved.
Severely dysplastic or dilated kidney
Stephens proposed pathogenic mechanisms to explain the development of renal dysplasia.
These include (1) defects of the
ureteric bud or its branches, (2) qualitative or quantitative deficiencies of the nephrogenic mesenchyme,
and (3) vascular ischemic insults with resultant
ureteric obstruction and renal cystic dysplasi
may result form inability of bladder to generate sufficient pressure with a detrusor contraction.
may be dilated or thickened.
Related to abnormal mesenchymal-epithelial development.
Reduction of both epithelial and smooth muscle cells and increase in connective tissue cells.
affect the amount and content of the seminal fluid. associated which affect
sperm delivery and maturation.
Contrast studies requiring risky instrumentation are
avoided in those infants with good renal function
To allow pulmonary maturation,surgical reconstruction is usually the upper ureter is anatomically and histologically
the most normal and should be preserved if later tailored reconstruction is electe
This redundancy partially
obstructs the membranous urethra.
The major criticisms of this technique are
that it does not improve abdominal wall thickness,
and lateral bulging is not completely eliminated.
