PUJO

DEFINITION
• A ureteropelvic junction (UPJ) obstruction can be thought of as a
restriction to flow of urine, from the renal pelvis to the ureter, which,
if left uncorrected, leads to progressive renal deterioration.
• The response to obstruction is the development of renal pelvic
hypertrophy, in which the kidney compensates to maintain adequate
urinary flow.

Introduction
• Prevalence of antenatally detected hydronephrosis (ANH) ranges from 0.6-5.4%
• Bilateral in 17-54%
• ANH resolves by birth or during infancy in 41-88% patients
• Urological abnormalities requiring intervention are identified in 4.1- 15.4%
• USG - mainstay of fetal imaging

PUJ Obstruction
• Found in 50% of patients diagnosed with antenatal hydronephrosis.
• 5% - within the first year of life , 50% - before the age of 5 years
• Recognized in nearly 1 in 500 live births
• Boys: Girls = >2:1 Left : Right = 2:1
• Bilateral in 10-40%

PATHOLOGIC CHANGES OF OBSTRUCTION
GROSS
• kidneys - enlarged, cystic
appearance
• Dilation of the pelvis and ureter
and blunting of the papillary tips
• Cortex edematous & slightly
enlarged
• diffuse thinning of cortex and
medullary tissue
MICROSCOPIC
• Widespread glomerular collapse
and tubular atrophy, interstitial
fibrosis, and proliferation of
connective tissue in the
collecting system --- 5 to 6
weeks after obstruction

Differentiation
Differentiation is the process of cells attaining specific functional traits to
permit specialized functions and organization into tissues.
It is the basis for renal function,
Obstruction affects these finely tuned patterns, as can be seen histologically
in a severely obstructed kidney with dysplasia.

FIBROSIS
A universal characteristic of obstructive nephropathy
appears to be renal fibrosis
It is seen as infiltration of the interstitium with abnormal amounts of ECM,
including collagen, fibronectin, and other connective tissue proteins.
Their presence disrupts the normal interconnections between cells that
permit functional integration of the renal tissues.

• Modulation of renal fibrosis may be a significant potential target for managing
obstructive nephropathy,but the delicate balance of these factors needs to be understood
to a greater degree.
• Nitric oxide has also been shown to regulate the development of obstructive fibrosis
postnatally and may play a similar role prenatally
• Increased nitric oxide generation reduces the degree of interstitial fibrosis

FUNCTIONAL INTEGRATION
Renal function is regulated at numerous levels, including vascular,
neural, and hormonal factors, this may be significantly affected by inflammatory
processes(absent in congenital obstruction)
Although inflammatory changes do not appear to be a major
factor in early postnatal congenital urinary obstruction but it is likely that they begin to play a
greater role with age
Congenital obstruction alters both the ongoing functional integration of the kidney as well as the
development of the mechanisms that are intrinsic to this regulation.

DIFFERENTIAL DIAGNOSIS OF ANH
• Transient / Physiologic 41-88%
• UPJ obstruction 10-30%
• VUR 10-20%
• Megaureter 5-10%
• MCDK 4-6%
• PUV 1-2%
• Others - Duplex kidneys, urethral atresia, urogenital sinus, prune belly
syndrome, tumors

Transient Hydronephrosis
• Incidence - 41 to 88 %
• Due to mucosal folds , natural kinks , PUJ – narrowing.
• Cut – off :
• 2nd trimester – < 6mm
• 3rd trimester - <8mm
• Self resolving

Ureteropelvic Junction Obstruction
• U/L or B/L
• Little rationale for in utero intervention or early delivery
• In massive dilation - Therapeutic aspiration to prevent dystocia

Ureterovesical Junction Obstruction
• Less common than UPJ-O
• Characterized by ureteral dilation along with varying degrees of renal
pelvic and calyceal dilation
• Ectopic ureter inserting into the bladder neck, or high-grade VUR
• Differentiation is made postnatally

Vesicoureteral Reflux
• Cannot be definitively diagnosed on prenatal usg
• Severity of ANH is not indicative of VUR and may not be the appropriate trigger
for postnatal evaluation
• VUR diagnosed on postnatal evaluation for ANH is associated with earlier
resolution of VUR

Posterior Urethral Valves
• Diagnosis made prenatally
• Mandates prompt postnatal intervention
• Fetal USG findings
• Bilateral HUN
• Thick-walled bladder
• Dilated posterior urethra – KEYHOLE SIGN
• Dysplastic renal parenchymal changes with perinephric urinomas and
urinary ascites

Multi Cystic Dysplastic Kidney
• Confused with U/L PUJ-O
• Findings
• Multiple non - communicating cysts
• Minimal or absent renal parenchyma
• Absence of a central large cyst

Grading Systems

Society for Fetal Urology (SFU) Grading System

Grignon USG Grading System
Grade Calyceal dilatation
I
II
III
IV
V
• Physiological dilatation
• Normal calyces
• Slight dilatation
• Moderate dilatation
• Severe dilatation +
atrophic cortex
A-P diameter
1cm
1-1.5cm
>1.5cm
>1.5cm
>1.5cm

Etiology of PUJO
Intrinsic Factors
• Narrowed segment of the ureter at the PUJ:
• Adynamic segment/intrinsic narrowing:
• Incomplete development of the circular muscle fibres
• Alteration/ excessive collagen fibre
• Neuronal depletion in the proximal ureter
• Attenuated muscle bundles
• “Ostling's folds”: valvular mucosal folds
• appear at the 4th month of gestation
• due to differential growth of the ureter
• disappear with a person's linear growth
• Ureteral polyps

Extrinsic factors
• Aberrant/accessory/early
branching lower pole vessel
• Fibrous band
• This type of obstruction reported
to occur in up to 40% of patients
• In contrast to older children and
adults, crossing vessels are rarely
encountered in young children
with prenatally detected
hydronephrosis

Secondary causes
• Severe VUR - 10%
• Stone related scars
• Iatrogenic (prior surgery at the
PUJ/failed repair)

PUJO - Workup
• Urine analysis and culture
• Routine hematological investigations
• Renal ultrasound – first investigation to pick up PUJO
• VCUG - to evaluate for VUR
• CECT
• Nuclear Renogram - DTPA, MAG-3, MRU
• Retrograde Pyelogram

USG
• Ideally suited as a screening study and for
following patients with known
abnormalities
• Classical “bear paw” appearance on US
• Highly accurate in the diagnosis of renal
dilatation
• Not reliable in predicting obstruction or
providing information regarding renal
function.

Voiding Cystourography
• VCUG : to rule out the presence of
VUR (13-42% infants)
• Necessary to prove that the ureter is
normal in caliber and not obstructed
before repair of PUJO is done

MAGNETIC RESONANCE IMAGING
• Gadolinium-DTPA (Gd-DTPA)
• Offers excellent anatomic resolution and soft tissue contrast
• Does not use ionizing radiation
• Gd-MRU is the only study to date that has the capability of providing
excellent morphologic detail as well as functional information
• Ability to reliably detect hydronephrosis and transition in ureteral
caliber even in nonfunctioning systems

MR UROGRAPHY
• Cortical phase - the renal cortex
enhances vividly, differentiating
renal cortex from medulla.
• Medullary phase - medulla
enhances greater than the cortex.
• Excretory phase - excretion of
contrast medium into the collecting
system and ureters
maximum intensity projection (MIP) images

MR UROGRAPHY
Disadvantages
• Standardized equations and values used to determine function and
classify drainage have not yet been wholly agreed on.
• Sedation is required for most children.
• Increased costs associated with MRU and availability remains limited.

DIURETIC RENAL SCINTIGRAPHY
• Substantially low dose of radiation is absorbed (virtually zero) as
compared to contrast assisted imaging
• First radiotracer used Iodopyracet (Diodrast) in 1950’s – disadvantage
was significant hepatic uptake
• Performed after 6-8 weeks of age in infants
• Repeated after 3-6 months in infants where ultrasound shows
worsening of pelvicalyceal dilatation

DIURETIC RENAL SCINTIGRAPHY
• Differentiates between obstructive and non-obstructive
hydronephrosis and estimates relative renal function
• Hydroureteronephrosis can be obstructive or non obstructive
• Whitaker Test – standard test to differentiate obstructive and non
obstructive dilatation of renal pelvis and ureter.
• Invasive test, no information about renal function, non physiologic

DIURETIC RENAL SCINTIGRAPHY
• Diuretic renography is a non invasive test to detect obstruction
• Principle – first to demonstrate a prompt collecting system with or without
any delay in excretion
• Loop diuretic like furosemide – given at the plateau of activity in the
collecting system
• > 50 % washout in a non obstructed system within 12-15 mins after diuretic
injection

DIURETIC RENAL SCINTIGRAPHY
• Obstruction results in increase radiotracer accumulation in the pelvis
• Partial obstruction and renal insufficiency give confusing results
• 99mTc - 6 hours half life – ideal radiotracer
• Easily available, less radiation

DIURETIC RENAL SCINTIGRAPHY
Glomerular
Filtration
Tubular
Secretion
Tubular
fixation
Half Life
Tc-99m DTPA >95% - - 6.5 hours
Tc-99m
MAG3
<5% 97% - 6 hours
Tc-99m EC >95% - - 6 hours
Tc-99m
DMSA
<5% - 60% 6 hours
I-131 OH 20% 80% - 8 days

131I – Iodohippurate
• First used in 1960’s for renal imaging
• Used to detect ureteral obstruction, quantitative and
qualitative renal function
• Not used now because of the thyroid uptake of 131I and
longer half life (7 days)

99mTc Mercaptoacetyltriglycine (MAG-3)
• First used in 1986
• Principally cleared by proximal tubular secretion
• No significant glomerular filtration
• More useful in immature or chronically insufficient kidneys
than DTPA
• 0.5 % hepatic uptake
• Has to be boiled for radiolabelling – practical disadvantage
• FDA approved

99mTc- Ethylenedicysteine (EC )
• Kit form available at room temperature, no need to boil
• Not FDA approved
• Preferred over DTPA in patients with deranged renal function
• Faster clearance than DTPA, results in less radiation being delivered

99mTc – Diethylenetriamine Pentaacetic Acid (DTPA)
• Available since 1970, cleared almost exclusively by glomerular
filtration
• Clearance a few percentage points less than Inulin
• Slower renal clearance (as compared to tubular agents like MAG-3)
can lead to potential problems of interpretation
• Ostruction/ no obstruction, individual renal function, filtration
fraction, and renal transit times

99mTc – Dimercaptosuccinic Acid (DMSA)
• Acts on the principle of tubular fixation
• Used primarily to evaluate renal morphology, scarring, function
• Rarely used in the evaluation of PUJO

Choosing Renal Radiotracers
CLINICAL QUESTION AGENT
Perfusion MAG3, DTPA
Morphology DMSA
Obstruction MAG3, DTPA, OIH
Relative function ALL
GFR quantitation EC, DTPA

Three parts of a given renal nuclear scan
• The images of the kidneys
• The graphical representation/curve
• The numerical values

• The images given are actually 2 sets of images
• 1st one represents the perfusion phase and images are taken at 1
image/sec after injecting contrast.
• Contrast usually reaches both kidneys simultaneously and within 5
seconds.
• Thus both kidneys should be seen together after 5 second image.

• The second set of images are taken at 1 image/min and represent
intra renal transient time and excretion of contrast into PC system and
reaching bladder.
• Usually intra renal transient time (IRT) is less than 5 mins, so contrast
should be seen in PC system by 5 images.
• Delay in IRT represents obstruction.

O’REILLEY Curves /
time activity curves

Numerical values...
• The third part of the
report is numerical
values
• GFR, IRT and split
function

• According to the timing of Lasix administration - 3 protocols.
• F + 20 - Furosemide is injected 20 minutes after the injection of
tracer.
• F (– 15) - Furosemide is injected 15 minutes prior to the tracer.
• F – 0 - Furosemide is injected at the beginning of the study.

RENAL DIURETIC SCAN

Pitfalls in Nuclear Scans
 Significant motion can also alter the image quality.
 High background activity seen in CKD and immature kidneys of infants.
 Dehydration - progressive tracer accumulation within the PCS
 Failure of child to hold his urine until requested
 99mTc-DTPA tends to overestimate in patients with low GFR and underestimate in patients with high GFR
compared to inulin
 Photopenic areas will show less function.

Indications for Intervention
Symptomatic (pain, palpable lump, hematuria, recurrent febrile UTI,
hypertension)
Reduction of differential renal function by more than 5- 10%
Worsening dilatation with evolving parenchymal thinning
Contralateral compensatory hypertrophy
B/L UPJO
Solitary kidney
Development of stones

Endourologic Management
• Endopyelotomy
• Retrograde Ureteroscopic Endopyelotomy
• Cautery wire balloon
• Improved ureteroscopic instrumentation, laser technology, and better
outcomes make ureteroscopic endopyelotomy the current retrograde
approach of choice.

Intubated Ureterotomy
• Davis Intubated Ureterotomy, first described in 1943, rarely used
today
• A ureterotomy is performed from at least 1 cm above the stricture to
1 cm below
• Proximal diversion established with a well-located nephrostomy tube
and a stent placed across the ureterotomy.
• Stent kept for 4 to 6 weeks.
• 70% satisfactory result

Operative Intervention
• Preferred by most urologists
• Universally applicable to the
different clinical scenarios
• Retroperitoneal approach is
standard
• Transperitoneal if bilateral
• No need of stent if straight forward
repair in pediatric population –
avoids another GA
• Durable with long term recurrence
of 5%
Anderson Hynes
Dismembered Pyeloplasty

Reduction Pyeloplasty
• For a large or redundant pelvis a
reduction pyeloplasty is
performed by excising the
redundant portion between
traction sutures.
• Cephalad portion of pelvis is
closed with running sutures
down to the dependant portion.
• The dependant aspect of the
pelvis is then anastomosed to
the proximal ureter.

Dismembered Pyeloplasty in Crossing Vessel
• Originally described by
Hellstrom and Vahlquist.
• The technique is only feasible in
cases of anterior lower pole
accessory vessel without any
intrinsic pujo

Foleys Y-V Plasty
• Best applied to a upjo with high insertion of ureter.
• The base of the V is positioned on the dependant
medial aspect of the renal pelvis and the apex at
the upj
• The incision from the apex of the flap which
represents the stem of the Y is carried along the
lateral aspect of the proximal ureteral wall into an
area of normal caliber
• The apex of the pelvic flap is brought to the most
inferior aspect of the ureterotomy incision
• The posterior walls are approximated using
interrupted or running sutures
• Anastomosis is completed with approximation of
the anterior walls of the pelvic flap and
ureterotomy.

Culp DeWeerd Spiral Flap
• Indicated for relatively long areas of proximal ureteral
obstruction when the UPJ is already in a dependent position.
• Spiral flap is outlined with Base of the flap is situated
obliquely on the dependant aspect of the renal pelvis.
• The base of the flap is positioned anatomically lateral to the
UPJ between the ureteral insertion and renal parenchyma
• The flap is spiraled posteriorly to anteriorly
• The anatomically medial line of incision is carried down
completely through the obstructed proximal ureteral
segment into normal caliber ureter
• The longer the segment of the proximal ureteral obstruction ,
the farther away the apex, to preserve vascular integrity to
the flap the ratio of flap length to width should not exceed 3
to 1
• Once the flap is developed the apex is rotated down to the
most inferior aspect of the ureterotomy
• Anastomosis is completed over an internal stent using fine
absorbable sutures

Scardino Prince Vertical Flap
• Used when a dependant ureteropelvic
junction is situated at the medial margin of a
large , box shaped extrarenal pelvis
• The base of the flap is situated more
horizontally on the dependent aspect of the
renal pelvis between the UPJ and renal
parenchyma
• The flap is formed by two straight incisions
converging from the base vertically upto the
apex on either anterior or posterior aspect of
renal pelvis
• The apex of the flap is rotated down to the
most inferior aspect of the ureterotomy
• The flap is closed by approximating the edges
with interrupted or running sutures

Ureterocalicostomy

• The ureter is identified in the retroperitoneum and dissected proximally as far as possible
• The kidney is mobilised to gain access to the lower pole and perform anastomosis
without tension
• Lower pole nephrectomy is performed to expose a dilated lower pole calyx
• Proximal ureter is spatulated laterally
• Anastomosis is performed over a stent
• Initial suture is placed at the apex of the ureteral spatulation and the lateral wall of the
calyx with another suture placed 180 degrees from the first suture
• Anastomosis is completed in an open fashion placing each suture circumferentially but
not securing them until the anastomosis has been completed
• Renal capsule is closed over the cut surface of the parenchyma
• The anastomosis should be protected with a graft of perinephric fat or with a peritoneal
or omental flap

Endopyelotomy - Basics
• Endopyelotomy was coined by Badlani et al. (1986)
• Full-thickness lateral incision through the obstructing proximal ureter,
from the ureteral lumen out to the peripelvic and periureteral fat.
• Double J stent in kept in place for 6 weeks
• Based on the original work of Davis in 1943, who performed an
“intubated ureterotomy” to repair UPJO

Techniques
• Antegrade of retrograde approach
• Holmium laser/ cold knife (straight or hooked)/ electrocautery/
balloon with a cutting wire (Acucise) /Balloon dilation and rupture
(Endoburst)
• Invagination Technique
• Percutaneous Endopyeloplasty

Endopyelotomy
Advantages –
• Reduced hospital stay
• Early postoperative recovery
• Concomitant stones can be dealt in the same sitting
• Transplantation complications are particularly suited to
endoscopic management, either antegrade or retrograde

Endopyelotomy
Disadvantages –
• High failure rates in crossing vessels
• Bleeding
• Urine leakage
• Hydropneumothorax
• The success rate does not approach that of open,
laparoscopic, or robotic pyeloplasty.

Cold Knife Endopyelotomy
Vaarala et al. (2008) reported a small series of 64 patients who
underwent either antegrade or retrograde cold knife or cautery wire
balloon endopyelotomy. In this study, success rates ranged from 79% to
83%, without statistically significant differences among the three

Ureteroscopic Electrocautery
• The UPJ is first inspected for the presence of any transmitted
pulsations
• Incised laterally, between 8 and 9 o’clock on the right and between 3
and 4 o’clock on the left.
• Short and shallow strokes performed
• Any bleeding site is controlled by means of spot electrocoagulation

Ureteroscopic
Electrocautery

Cautery Wire Balloon Endopyelotomy
• Under fluoroscopic guidance the Acucise
catheter (6Fr) is advanced over a guide wire
up to the UPJ.
• 10/24 Fr low‐pressure balloon (3cm)
• The balloon is gently inflated with 0.5 ml
diluted contrast medium to ensure correct
positioning
• Active wire is directed laterally
/posterolaterally
• The cutting wire is activated at 75–100 W
(pure cutting power) for 5 seconds
Acucise catheter

• Simultaneously 2 ml diluted contrast medium is instilled into the dilating
balloon.
• As the balloon inflates, the stricture is incised
• The balloon is kept inflated for 10 min to tamponade the incision site.
• Retrograde pyelography is performed to confirm extravasation at the
incision site.
• 14-7 Fr endopyelotomy or regular 7 Fr Double-J stent is kept for 6 weeks
• Provides similar long-term success rates as compared to holmium laser

Endoburst - Balloon dilation and rupture
• Retrograde access - 24–30 Fr angioplasty balloon is inserted over a
guidewire and positioned across the UPJ under fluoroscopic control.
• The balloon is inflated until wasting completely disappears.
• Several inflation/deflection cycles are recommended in order to
ensure that no residual narrowing remains.
• Long‐term success with this technique has been inferior to that with
incisional techniques

Retrograde Ureteroscopic Endopyelotomy
• Can be traced back to the original descriptions of Albarran, Keyes, and
Davis.
• Both the antegrade and retrograde endopyelotomy follow the
concept of Davis’s intubated ureterotomy, first described by Davis in
1943.
• Wickham and Kellet described the first ureteroscopic pyelolysis of the
UPJ in 1983
• First reported in 1985 - Bagley et al reported a combined
percutaneous and flexible ureteroscopic procedure.

• Advantages - allows direct visualization of the UPJ
- no need for percutaneous access
- patient compliance, less morbidity
- more cost effective than balloon endopyelotomy,
antegrade endopyelotomy, and pyeloplasty
• Disadvantages – distal ureteric stricture
concomitant stone disease

Holmium Laser
• 200 μm flexible ureteroscope
• 365 μm semirigid ureteroscope
• Setting of 1.5 to 2.5 J and a frequency of
10 to 15Hz
• UPJ is incised laterally upto the peripelvic
and periureteral retroperitoneal space.
• As performed under direct vision, any
visualized vessels and significant bleeding
is usually avoided.

Holmium Laser

Complications
• Ureteral strictures
• Bleeding - angiographic embolization may be required
• Urinary leak
• Stent migration
• Infection
• Ureteroarterial fistula
• Ureteric Avulsion
• False Passage

Stent Duration
• Less is known.
• The original report and
recommendation of 6 weeks by
Davis (1943) is still used
• Mandhani et al. (2003) -
identified no difference in
results when comparing 57
patients stented for 2 weeks
versus 4 weeks.
Antibiotic Dose
• Although the need for
prophylactic antibiotics
while the stent is indwelling
is not literature based, many
use a daily suppressive dose.

Follow Up
• 1st follow up at 1 month for clinical and radiographic evaluation.
• Includes history, physical examination, urinalysis, and diuretic renography.
• If normal - reevaluation is performed at 6 months and then at 12 month
intervals.
• Majority of failures occur within the first year of the procedure
• 2-3 year follow up is justified because studies indicate that even at 36
months some late failures are identified, but relatively few are identified at
60 months

Invagination Technique
• First described by Gelet and colleagues
• Balloon is inflated below the UPJ.
• After percutaneous access - the inflated balloon is grasped from
above and pulled inside the renal pelvis, invaginating the UPJ and
proximal ureter.
• Holmium laser or electrocautery used to incise the double tissue layer
down to the plastic balloon.

Invagination Technique
• If residual narrowing is suspected - balloon is reinflated on its way
out to calibrate the ureter.
• Spontaneous reduction of the invagination occurs when the
balloon is deflated.
• Rest of the procedure same as other techniques
• Advantages - UPJ is stabilized on the dilated balloon
- reduces the risk of damaging crossing vessels

Percutaneous Endopyeloplasty
• 5 mm suturing instrument used for
placing interrupted sutures
• Can be inserted through working
channel of a 26-French Storz
nephroscope.
• A 30-French Amplatz sheath is
positioned after poercutaneous
access
• Conventional endopyelotomy
performed
SewRite 5SR

Percutaneous Endopyeloplasty

Percutaneous Endopyeloplasty
• First described in 2002
• Stein et al. (2007) reported 55 patients with short term follow up with
more than 90% success.
• May not be effective for secondary UPJO because tissue scarring may
inhibit the endoscopic reconstruction.
• Lezrek et al (2012) reported a modified technique requiring no specialized
equipment ( 3.5 mm laparoscopic needle holders and a nephroscope) in 10
patients

Failed PUJO
• Pelviureteric junction obstruction (PUJO) of the kidney can lead to a
number of different clinical manifestations, which often require surgical
intervention.
• Although the success of pyeloplasty and endopyelotomy are good, there
are still a number of patients who fail primary treatment and develop
secondary PUJO.
• These treatment failures can be a challenging cohort to manage.
• Failure can be considered as the inability to improve symptoms, dynamic
renographic parameters, renal unit function or hydronephrosis.

The causes of failed treatment include :
Poor surgical technique
Irreparable pelvi-caliceal system
PUJ ischemia with re-stenosis
Anastomotic leak with urinoma and fibrosis
Missed crossing vessel in 18%-50% of cases,
Ureteric stent malfunction and diabetes.
Most treatment failures present within the first 18 months following the
procedure.
However, secondary PUJO has been identified in patients up to 5 years after
primary treatment.[15]

• There are a number of options available to the clinician for management of
secondary PUJO.
• The best option for the patient will depend on numerous factors including;
Individual upper tract anatomy,
Presence of renal calculi,
Concurrent medical conditions,
Informed patient preference,
Availability and experience of individual techniques,
Symptoms, renal function and the type of primary treatment modality.

Treatment options
• Antegrade and retrograde endopyelotomy .
• Pyeloplasty (open, laparoscopic, robotic).
• Complex reconstruction; ureterocalycostomy, ileoureteral replacement.
• Autotransplantation ± boari flap pelvivesicostomy.
• Long-term ureteric stenting or percutaneous nephrostomy.
• Nephrectomy (open or laparoscopic)
• Observation.