This document provides an outline and overview of pelviureteric junction obstruction. It discusses the epidemiology, relevant anatomy, etiology, pathophysiology, clinical features, investigations, and management including surgical and non-surgical treatment options. The standard surgical procedure for repair is the Anderson-Hynes dismembered pyeloplasty technique, which involves excision of the narrowed segment and anastomosis of the renal pelvis to the ureter. Other approaches include endoscopic techniques, laparoscopic pyeloplasty, and robotic-assisted surgery. Proper pre-operative evaluation and post-operative care are important for optimal outcomes.

1. Dr ONYEZE CHIGOZIE I
SENIOR REGISTRAR, UROLOGY UNIT
SURGERY DEPARTMENT
OAUTHC

2. Outline
 Introduction
 Epidemiology
 Relevant Anatomy
 Etiology
 Pathophysiology
 Clinical features
 Management
 Clinical evaluation
 Investigation
 Treatment
 complication
 Prognosis
 Future trends
 Conclusion

3. Introduction
 Pelvi-ureteric junction (PUJ) obstruction refers to
impairment of the normal transport of urine from the
Renal Pelvis to the ureter
 most cases are congenital, the problem may not
become clinically apparent until much later in life
 It is important because if not detected and treated
early, can lead to progressive deterioration of renal
function

4.  Since the first reconstruction of an obstructed kidney in the late
1800s by Trendelenburg, surgery for PUJ obstruction has evolved
significantly.
 In 1936, Foley described the results of 20 pyeloplasties using the
so-called YV-plasty repair.
 In 1946, Anderson and Hynes published their experience with an
operation that included complete transection of the upper
ureter, subsequent spatulation of the distal ureter, and trimming
of the redundant pelvis.
 This highly successful technique has become the standard for
surgical repair used today, even in robotic pyeloplasties.

5. Epidemiology
 Incidence is 1 in 1000 live births
 PUJ Obstruction is more common in boys than in girls,
especially in the newborn period with M:F ratio of 2:1.
 As many as 67% of cases involve the left kidney in the
newborn period

6. Epidemiology contd
 Bilateral cases (synchronous and asynchronous) are
observed in 10-40% of cases
 however, fewer than 5% of patients require bilateral
repair because of spontaneous resolution in a
significant number of cases.
 A fairly high (up to 40%) rate of associated
vesicoureteral reflux (VUR) has also been reported.
 The reflux is usually of relatively low grade and may
resolve spontaneously.

7. Relevant Anatomy

9. EMBRYOLOGY
 During embryogenesis, the ureter arises from the
ureteral bud and extends towards the area of
parenchyma that will become the kidney
 The PUJ is formed during week 5 of embryogenesis
 By weeks 10-12 of gestation, the initial tubular lumen
of the ureteric bud becomes canalized, with the PUJ
area being the last to canalize.
 Inadequate canalization of this area is the main
embryologic explanation for PUJ obstruction.

10. Embryology
 It has been suggested that the pelviureteric and
ureterovesical portions of the ureter are the last to
canalize; thus, failure of the process to complete
would lead to partial canalization.
 Another theory for the development of an obstructive
process suggests premature arrest of ureteral wall
musculature development leading to the
persistence of an aperistaltic segment at the level
of the PUJ, thus preventing normal propulsion of
urine down the ureter.

11.  PUJ obstruction may be associated with other
congenital anomalies, including the following:
• Imperforate anus
• Contralateral multicystic kidney
• Congenital heart disease
• VATERL
• Esophageal atresia

12. Etiology
PRIMARY
Intrinsic:
Commonest is PUJ STENOSIS
Idiopathic functional obstruction
Aperistalsis (rare in infants)
Ureteral polyp and Ureteral valves
Extrinsic: -
Abnormal crossing vessels
Accessory early branching lower pole segment vessels
High insertion of ureter on the pelvis

13. EXTRINSIC CAUSES
SECONDARY
 Retroperitoneal fibrosis
 Extrinsic hepatic/splenic tumour
 Fibroepithelial polyp
 Urothelial malignancy
 Stone diseases
 Upper ureteric stricture following TB, Endoscopy


14. Pathophysiology
 The urinary drainage from renal pelvis to ureter is
determined by many factors.
 Pressure within the renal pelvis is determined by
 the volume of urine produced
 the internal diameter of the PUJ and collecting system
 the compliance of the renal pelvis
 the peristaltic activity of the ureter.

15.  In response to the increased volume and pressure, the renal
pelvis dilates.
 Initially, the smooth muscle of the renal pelvis may thin
out, but over time, it may become hypertrophied to varying
degrees.
 The effects on the developing renal parenchyma may be
quite variable, owing to the compliance of the renal
collecting system. Despite massive dilation, preservation of
renal function may occur.

16. PRESSURE-DEPENDENT AND
VOLUME-DEPENDENT FLOW
 In instances of intrinsic obstruction, at low urinary
flow rates, no obstruction exists; however, as the flow
rate increases, the urinary bolus is not conducted,
which causes the renal pelvis to distend.
 This pattern is referred to as pressure-dependent or
volume-independent flow.

17.  On the other hand, in cases of extrinsic compression
usually caused by aberrant vessels, urine flow is
impeded only after a definite amount of urine is
collected in the renal pelvis.
 This is an example of volume-dependent flow, and
the pressure damage is only evident intermittently.

18.  Significant urinary obstruction may result in
 tubular dilation
 Glomerulosclerosis
 Inflammation
 fibrosis.
 A good correlation exists between the severity of these
histologic changes and the function remaining in the
affected kidneys.

19. Management
 This entails
 Clinical evaluation
 History
 examination
 Investigation
 Treatment


20. History
Prenatal
Prenatal screening sonography
Children and Adults
o Asymptomatic
o Episodic flank or abdominal pain
o Palpable Flank mass
o Recurrent UTI
o Nausea and/or vomiting
o Feeding difficulty
o failure to thrive
o Gross haematuria following mild abdominal trauma

21. Examination
 General physical examination
 Pallor, edema
 Vital signs
 May have elevated BP
 Abdominal examination
 Renal angle tenderness
 Ballotable kidneys

22. Investigation
 Maternal ultrasonography
 Widespread use of antenatal ultrasonographyhas
opened the field of perinatal urology
 However, even the most modern ultrasonographic
techniques only demonstrate dilation of the renal pelvis
and ureter and cannot accurately differentiate true
obstruction from a harmless physiologic dilatation.

23.  Things to evaluate during prenatal USS
 Amniotic fluid volume to rule out oligohydramnios
 Bladder volume
 Kidney size
 Anteroposterior (AP) diameter of the renal pelvis
 Any associated abnormalities
 Significant hydronephrosis is said to occur if
 the AP diameter of the renal pelvis is more than 10 mm
 the ratio of the renal pelvis to the AP kidney is more than 0.3
 evidence of caliectasis is present after 24 weeks of gestation.

24.  ABDOMINOPELVIC ULTRA SOUND SCAN
 Anterior-posterior renal pelvis diameter (APD)
 Calyceal dilation
 Renal parenchymal thickness
 Renal parenchymal appearance
 Bladder abnormalities
 Ureteral abnormalities

25.  The Society for Fetal Urology [SFU] grading system for hydronephrosis is
as follows
• Grade 0 - No hydronephrosis, intact central renal complex seen on
ultrasonography
• Grade 1 - Only renal pelvis visualized, dilated pelvis on ultrasonography, no
caliectasis
• Grade 2 - Moderately dilated renal pelvis and a few calyces
• Grade 3 - Hydronephrosis with nearly all calyces seen, large renal pelvis
without parenchymal thinning
• Grade 4 - Severe dilatation of renal pelvis and calyces with accompanying
parenchymal atrophy or thinning

26. Doppler ultrasonography
 With this modality, intrarenal vasculature can be
assessed to determine the resistive index. Normal kidneys
reliably demonstrate resistive indices less than 0.7, and
obstructed kidneys show higher values.
 Administration of diuretics can aggravate the preexisting
obstruction, thereby aiding the diagnosis by Doppler
ultrasonography.
 It is especially reliable in the preoperative diagnosis of
aberrant accessory blood vessels associated with PUJ
obstruction.

27. Computed tomography
 Computed tomography (CT) urography provides an
accurate assessment of
 the significance and severity of UPJ obstruction,
 the precise preoperative anatomy, and the physiologic
significance in a single examination.
 Anatomy of aberrant vessels
 secondary kinks, and adhesions
 The limitations in the application of this modality to
small children where there is need for sedation and
the exposure to radiation.

28. Magnetic resonance imaging
 MRI with contrast-enhanced magnetic resonance
angiography (MRA) is a reliable means of detecting
aberrant or obstructing renal arteries in children with
UPJ obstruction.
 Magnetic resonance urography (MRU) has also been
shown to have diagnostic utility and has the advantage
of being able to demonstrate vascular and urinary tract
anatomy.

29. Diuretic renography
 Diuretic renography is the most widely used
noninvasive technique to determine the severity and
functional significance of PUJ obstruction.
 Technetium-99m mercaptoacetyltriglycerine
(99mTc-MAG3) is the ideal tracer in the pediatric
population.
 Strongly bound to protein, MAG3 is mainly
intravascular and secreted by proximal renal tubules,
with a small fraction being filtered by the glomeruli.

30.  The rate at which tracer leaves the renal pelvis following
diuretic injection, reflected in the slope of the drainage
curve and often reported as T1/2
 Rapid drainage (low T1/2) indicates no obstruction, while
impaired drainage or slow or no washout (T1/2 >20 min)
indicates obstruction.
 One of the most useful measurements in diuretic
renography is the estimate of differential renal
function. This is considered significant when it is less than
40%.

31. Intravenous pyelography
 IVP provides information about the obstruction and
contralateral side and especially facilitates operative
planning
 It accurately visualizes kidney, renal pelvis, ureter, and
the exact point of obstruction. IVP also allows clear
visualization of malrotated renal units.

32.  The drawbacks of IVP include
 Bowel gas and underlying bony structures also make
interpretation of the urogram difficult.
 the necessity of dehydration even in infants, which
makes it a relatively risky procedure.
 a risk of radiation exposure which can be minimized by
limiting the number of films taken.
 Problems associated with contrast media such as
nephrotoxicity and anaphylactic reactions. These
problems can be reduced by using nonionic contrast
agents.

33. Pressure flow studies
 The Whitaker test,
 this was first introduced in 1973, and is a pressure flow study
that has proven useful in equivocal obstruction in children.
 The renal pelvis is accessed percutaneously, and the urine
transport capability of the PUJ is challenged by infusion of
extrinsic flow and simultaneous measurement of intrapelvic
pressure
 The Whitaker measurement records the response of the renal
pelvis to distention, which does not truly define obstruction.
In complex cases where intrinsic and extrinsic obstruction
coexist, this test does not provide conclusive evidence.

34. Other investigations
 FULL BLOOD COUNT
 ELECTROLYTE UREA AND CREATININE
 URINALYSIS
 URINE MCS

35. DIFFERNTIAL DIAGNOSIS
Multicystic kidney disease
Megaureter
ureterocele

36. TREATMENT
 The aim of treatment is to prevent or minimize renal
damage, as well as relief of symptoms
 It depends on the mode of presentation, as patient
may require an initial course of antibiotics
especially in cases of moderate-to-severe dilatations
because any urinary tract infection (UTI), especially in
the neonatal period, dramatically increases the chance
of fibrosis and parenchymal damage

37. INDICATIONS FOR SURGICAL
INTERVENTIONS
 Ipsilateral PUJ obstruction with less than 40% of differential renal function
(DRF) on diuretic renography
 Bilateral severe PUJ obstruction with renal parenchymal atrophy
 Obstructive pattern on diuretic renography with abdominal mass, urosepsis, or
other symptoms (eg, cyclic flank pain, vomiting)
 Recurrent UTI under antibiotic prophylaxis
 Worsening hydronephrosis on serial ultrasonography
 Development of stones
 Causal hypertension

38. Absolute contraindications
 Presence of uncorrected coagulopathy
 The absence of adequate treatment of active urinary
tract infection
 The presence of cardiopulmonary compromise
unsuitable for surgery

39.  Surgical options include
 Conventional open techniques
 Minimally invasive techniques
 Endourologic procedures
 Laparoscopic pyeloplasty
 Robotic-assisted pyeloplasty

40.  Pyeloplasty
 Anderson-Hynes dismembered pyeloplasty
 Flap procedure
 Foley Y-V plasty
 Culp DeWeerd spiral flap
 Scardion-Prince Vertical flap
 Intubated ureterostomy
 ureterocalycostomy

41. Anderson-Hynes dismembered
pyeloplasty
 Anderson-Hynes dismembered pyeloplasty is the most
commonly used open surgical procedure. It has a high
success rate with few complications in most cases
 It consists of
 excision of the narrowed segment
 Spatulation of the ureter
 Excision of redundant pelvis
 and anastomosis to the most dependent portion of the
renal pelvis

42. Endourologic approaches
 Balloon dilatations
 Percutaneous antegrade endopyelotomy
 Retrograde ureteroscopic endopyelotomy

43. LAPAROSCOPIC AND ROBOTIC
APPROACHES
 Laparoscopic pyeloplasty
transperitoneal
Retroperitoneal
 Robotic assisted laparoscopic approach

44. PRE-OP PREPARATION
 Clear indication
 Preoperative work up
 Informed consent
 Preoperative marking of the incision site

45. Intra operative period
 Anaesthesia
 General anaesthesia with cuffed endotracheal tube and
adequate muscle relaxation
 Prophylactic antibiotics at Induction of Anaesthesia
 Positioning
 This depends on the approach

46. Anderson-Hynes dismembered
pyeloplasty
 The extraperitoneal flank approach is advantageous in
that it provides excellent exposure
 Patient is positioned in a lateral decubitus position
with the affected side upwards and the table broken so
that lumbar support is raised to maximum height.
 It is vital to pad bony sites carefully
 Routine skin preparation and draping is done

47. OPERATIVE TECHNIQUES
 Incision
 may be subcostal but is usually performed through the
bed of the 12th rib or carried anteriorly off its tip
 Various muscles groups are divided down to the
retroperitoneum
 The peritoneum is swept off the anterior surface of the
Gerota’s fascia, which is subsequently incised

48.  The Proximal ureter is identified lying on the psoas
muscle and traced proximally to the renal pelvis
 Care is taken not to strip the peri-ureteral tissue to
avoid devascularizing it
 The site of obstruction at the PUJ is noted, and also
the presence of an aberrant vessel if present

49.  A stay suture is placed in the anterior aspect of the
ureter distal to the level of obstruction to aid proper
orientation during anastomosis
 Two stay sutures are then placed at the medial and
lateral aspects of the dependent portions of the pelvis.

50.  The site of obstruction is excised
 If a crossing vessel is present at the PUJ, It is
transposed anterior to the vessel.
 Redundant pelvis could be removed
 The lateral aspect of the ureter is spatulated with
scissors.

51. Anderson-Hynes Dismembered
pyeloplasty

52. Reduction pyeloplasty

53. Transposition of crossing vessels

54.  The Apex of the spatulated ureter is brought to the
inferior border of the lateral renal pelvis; and the
medial portion of the ureter to the superior edge of the
pelvis
 A pelviureteric anastomosis is done with a fine
interrupted or continuous suture such as 4-0 Vicryl.

55. Operative Principles
Developed by Foley in 1937
• Formation of a funnel at PUJ
• Dependent drainage
• Full thickness anastomosis
• Water-tight anastomosis
• Tension –free anastomosis

56.  A double-J stent or cumming’s catheter is inserted, to
ensure drainage, maintain patency and prevent
anastomotic stricture
 A 20Fr drain is placed in the renal bed
 Wound is closed in layer

57. Advantages of Anderson-Hynes
Dismembered pyeloplasty
 Almost universally applicable to all clinical scenario
 Can be used whether the ureteral insertion is high on the
pelvis or already dependent
 Permit reduction of a redundant pelvis
 Only a dismembered pyeloplasty allows complete excision
of anatomically or functionally abnormal PUJ itself
 Anterior and posterior transposition of crossing vessels is
possible

58. Limitations of Anderson-Hynes
Dismembered pyeloplasty
 Not well suited for PUJ obstruction associated with
lenghty or multiple proximal ureteral strictures
 Patient in whom PUJ obstruction is associated with a
small, relatively inaccessible intrarenal pelvis

59. FOLEY’S Y-V PLASTY

60. SPIRAL FLAP

61. Post operative management
 Intravenous fluids
 Analgesics
 Antibiotics
 Wound care
 Input output monitoring
 Removal of wound drain
 Plain abdominal xray to ascertain DJ stent position
 Removal of stent

62. Complications
 Hemorrhage
 Surgical site infection
 Post operative ileus
 Post obstructive diuresis
 Anastomotic leak

63. Prognosis
 The overall success rate with the dismembered repair
is quite satisfactory (90-95%)
 Long-term obstruction at the anastomosis can occur;
but reoperation for this is low, occurring in 2-5% of
cases.

64. Future Trend
 Urinary biochemical markers of renal damage
someday may aid the diagnosis of clinically significant
urinary obstruction
 Many biologic modulators of glomerular
dynamics and renal histology have been identified.
 The assessment of urine for growth factors (eg EGF,
PDGF, TGF-β), cytokines, and vasoactive substances
may be an important adjunct in evaluating obstructive
uropathy in the future.

65. Conclusion
 Pelviureteric junction obstruction is a important cause
of renal impairment
 Early diagnosis and prompt intervention can be help
preserve renal function

66. THANK YOU