•Under fluoroscopy, the PUJ is assessed and drainage through this segment is evaluated.

•High intrarenal pressures is indicative of PUJ obstruction.

•Low intrarenal pressures in the presence of hydronephrosis are consistent with normal variance.

•The Whitaker test is a pressure flow study that has proven useful in equivocal PUJ obstruction in children.

•A catheter is introduced percutaneously into the renal pelvis. The patency of the PUJ is challenged fluid infusion via the catheter and simultaneously measuring the intrapelvic pressure.

3.7Management of Newborns with PUJ Obstruction

•The timing of surgical correction of PUJ obstruction in newborns is highly controversial.

•Immediate surgery is not necessary for those newborns with relatively preserved differential renal function (>40 % of differential renal function).

•These patients can be observed safely nonoperatively as in some of them the obstruction will resolve spontaneously.

•These patients should be covered with antibiotic prophylaxis.

–The use of antibiotic prophylaxis in mild hydronephrosis is still controversial.

–Most authors advocate antibiotic prophylaxis for those with moderate-to-severe hydronephrosis (SFU grade 3 or 4).

•Urinary tract infection in these patients increases the chance of fibrosis and parenchymal damage.

•Patients with renal function >40 % are monitored with repeat renal scans at 3- to 6-month and 12-month intervals, and surgery is performed only if a clear deterioration in renal function is present.

•In cases in which the differential function is <10 %, some recommend the insertion of a

nephrostomy tube to determine whether return of function will be sufficient.

•Others consider this a non-functioning kidney and there is no point in inserting a nephrostomy. Add to this the fact that nephrostomy is difficult to maintain in infants and children and it is known to be associated with bacteriuria.

•Nephrectomy is indicated in those with a differential function <10 % and complicated by hypertension or recurrent urinary tract infection.

•Surgical Therapy:

–Prolonged partial PUJ obstruction is deleterious to the newborn kidney and can be reversed by early relief of the obstruction.

–Spontaneous resolution of hydronephrosis although well known, 15–33 % of patients with asymptomatic neonatal hydronephrosis show progressive ipsilateral renal deterioration, and about one half of them never regain the lost function by pyeloplasty.

–There is a definite percentage of patients with PUJ obstruction treated conservatively who will sustain irreversible renal damage that could have been prevented by early pyeloplasty.

•Indications for surgical interventions in PUJ obstruction:

–Unilateral PUJ obstruction with less than 40 % of differential renal function on diuretic renograms.

–Bilateral severe PUJ obstruction with renal parenchymal atrophy.

–Obstructive pattern on diuretic renograms with abdominal mass, urosepsis, or other symptoms.

–Recurrent UTI under antibiotic prophylaxis.

•A temporary percutaneous nephrostomy was advocated in newborns with severe hydronephrosis. The aims of this include (Figs. 3.40, 3.41, 3.42 and 3.43):

–To confirm the diagnosis and document the severity of obstruction.

–To drain the obstructed kidney and relive the pressure on the renal parenchyma.

–Newborns and because of the partial PUJ obstruction have a small size ureter that

Figs. 3.40, 3.41, 3.42, and 3.43 Percutaneous nephrostograms showing unilateral and bilateral PUJ obstruction in newborns and infants (Note the degree of

obstruction and the extent of hydronephrosis. The nephrostomy is also useful for temporary drainage of the obstructed kidney)

makes it difficult operatively to reconstruct the new PUJ and placing a temporary nephrostomy will time to decompress the kidney, increase the size of the ureter and allow the child to grow.

–Nephrostomy tubes are also known to be associated with complications including sepsis, kinking and spontaneous dislodgment.

3.8Treatment

•The aims of treating patients with PUJ obstruction are:

–Relive the obstruction

–Improve renal drainage

–Maintain or improve the renal function

•There is no evidence that prenatal intervention in infants with either a single obstructed

kidney or bilateral involvement improves renal outcome.

•Antenatal intervention however is recommended in those with extremely severe PUJ obstruction and only be done in centers with experienced surgeons as this may be associated with morbidity and fetal mortality.

•Asymptomatic patients with PUJ obstruction:

–The ultimate goal of management is to preserve renal function and avoid unnecessary surgery.

–Managing asymptomatic patients is challenging, because the natural course of PUJ obstruction is variable.

–It appears that many patients with PUJ obstruction will have stable renal function and improvement in the degree of hydronephrosis during long periods of observation.

–However, others will have deterioration of their renal function, and appear to benefit from surgical repair of PUJ obstruction.

–There is no reliable method to predict which patients with asymptomatic PUJ obstruction, their kidney function will deteriorated and whether the function of a kidney with PUJ obstruction will remain unaffected during the period of observation.

–As a result of this, there is controversy on the role of watchful observation with surgical intervention only in those who develop symptoms or if there is a decrease in renal function. This approach may prevent unnecessary surgery in some asymptomatic patients with PUJ obstruction.

–Patients with PUJ obstruction are monitored closely with renal ultrasonography and nuclear scans every 3–4 months.

–It is important to monitor the renal pelvic dilatation with serial ultrasounds. This is important to assess:

•Changes in renal pelvic dilatation

•Renal parenchymal thickness

•The presence of scarring, and function.

–Patients with asymptomatic PUJ obstruction should be monitored and followed-up with serial renal ultrasounds to detect any

change in the degree of hydronephrosis that may necessitate surgical intervention.

•Renal ultrasound evaluations are performed every 3–4 months until the

child reaches 1 year of age, every 6 months for the next 2 years, and then annually.

•If the renal ultrasound shows increasing hydronephrosis, a diuretic renogram is repeated to detect any change in renal function or confirm that the renal function is stable.

•If diuretic renogram shows deterioration of >10 % in the renal function on the affected side, or the relative renal function is <40 %, surgery is recommended.

•These studies are performed more frequently (every 2–3 months) if the relative renal function is borderline, and significant hydronephrosis is present.

–The problem is more complicated in those with bilateral asymptomatic PUJ obstruction as the relative renal function may not be a reliable measure.

–In these patients, glomerular filtration rate can be measured with serum creatinine and/or by renal scan. If renal function is significantly decreased, surgery is indicated to relieve PUJ obstruction.

–Antibiotic prophylaxis:

•This has been recommended in these patients because urinary stasis is believed to be a risk factor for urinary tract infection.

•This is also controversial and does not appear that it is beneficial in children with PUJ obstruction especially those with mild PUJ obstruction.

•There are those who advocate giving antibiotic prophylaxis for patients with severe, grade IV hydronephrosis until the time of the voiding cystourethrogram (VCUG). If the VCUG does not show vesicoureteral reflux, the prophylactic antibiotics are discontinued.

•Others will give prophylaxis antibiotics for all patients with PUJ obstruction.

•Children with PUJ obstruction who are symptomatic require operative intervention.

•Kidney stones sometimes develop in those with PUJ obstruction and these patients should be treated with open pyelolithotomy and pyeloplasty.

•Patients with PUJ obstruction who present with acute pyelonephritis are treated first with antibiotics. Surgical repair is performed when the infection has resolved but if pyelonephritis does not respond to antibiotics, a temporary percutaneous nephrostomy should be placed to drain the kidney and relieve the obstruction.

•Initially, most children with incomplete PUJ obstruction are treated conservatively and monitored closely.

•Monitoring of these patients include serial renal ultrasonography and renal isotope scan.

•Surgical intervention is indicated in patients with PUJ obstruction:

–Who are symptomatic (pain, hypertension, hematuria, secondary renal calculi, and recurrent urinary tract infections).

–With significantly impaired renal drainage or poor renal growth

–With deterioration of renal function (a serial loss in renal function >10 %).

–With clearance half-time (T 1/2) greater than 20 min, differential function less than

40 %, and ongoing parenchymal thinning with or without contralateral compensatory hypertrophy.

–With progressive increase in the size of renal pelvis on serial imaging.

–With bilateral PUJ obstruction and thinning of renal parenchyma.

•There are several methods to treat PUJ obstruction.

•Open surgical Therapy (Fig. 3.44):

Asymptomatic Patients with PUJ Obstruction

•Observation is appropriate for asymptomatic patients with PUJ obstruction and hydronephrosis that is mild to moderate in severity (i.e. Society of Fetal Urology [SFU] grade II to III).

•These patients are followed-up with ultrasound examination every 4 (Grade

III)to 6 (Grade II) months in the first year of life, then every 12–18 months thereafter.

•If there is an increase in the degree of hydronephrosis, a diuretic renogram is performed.

•If the affected kidney has <40 % of split renal function, or there is a serial loss

>10 % from a previous study, surgical intervention is recommended.

•Newborns who have persistent SFU grade IV hydronephrosis require closer observation and frequent renal ultrasound follow-up.

•In these patients, a diuretic renogram is performed at 6–8 weeks of age.

–If the hydronephrotic kidney has decreased renal function (<40 % of split renal function) compared with its normal contralateral side, surgical intervention is recommended.

–If the hydronephrotic kidney have equal function compared with the normal contralateral kidney, the renal sonogram is repeated in 4–6 weeks. If the sonogram shows improvement, these patients are followed-up with serial renal ultrasounds at 3–4 month intervals.

–Any worsening of the hydronephrosis calls for a diuretic renogram.

–If these serial sonograms show continued SFU grade IV hydronephrosis without substantial change from previous studies:

•Continued observation and monitoring including renal ultrasound and diuretic renograms

•If the family prefer, surgical intervention is recommended.

–In 1936, Foley introduced the YV-plasty for the correction of PUJ obstruction.

–Culp and DeWeerd designed a spiral flap in the dilated pelvis and used it to repair the defect of the PUJ.

–The Foley Y-V plasty is used to treat PUJ obstruction and those with the high-insertion variant but cannot be used in the presence of apparent lower-pole vessel.

–Spiral and vertical flaps (e.g. Culp and DeWeerd, Scardino and Prince) are useful for those with a long-strictured segment of the ureter. The proximal strictured ureter is

re-tubularized using the redundant renal pelvis.

–In 1946, Anderson and Hynes described their operation to treat PUJ obstruction. The Anderson-Hynes dismembered pyeloplasty is currently the most commonly used procedure to repair PUJ obstruction.

–In children, the procedure of choice to treat PUJ obstruction is an Anderson-Hynes dismembered pyeloplasty.

–The Anderson-Hynes dismembered pyeloplasty is particularly useful for those with the high-insertion variant of PUJ obstruction.

Indications for Surgery in PUJ Obstruction

•Symptomatic patients (flank pain, urinary tract infection, and renal stones).

•Unilateral PUJ obstruction with <40 % of differential renal function on diuretic renograms or there is a serial loss in renal function >10 %.

•Bilateral severe PUJ obstruction with renal parenchymal atrophy.

•Obstructive pattern on diuretic renograms with abdominal mass, urosepsis, or other symptoms (e.g., cyclic flank pain, nausea, vomiting).

•Recurrent UTI in spite of antibiotic prophylaxis.

•Massive hydronephrosis (renal pelvis diameter >4–5 cm.

•Parental preference in those who require frequent observation and invasive testing.

Patients with renal function more than 40 % on the affected side are monitored with repeat renal scans at 3- to 6-month and 12-month intervals, and surgery is performed only if a clear deterioration in renal function is present.

Patients with Renal Differential Function <10 %

•Some recommend insertion of a nephrostomy tube to determine whether return of function will be sufficient.

•Others consider nephrectomy to relieve recurrent infection or renal hypertension.

•In the absence of significant hydronephrosis, some surgeons will observe these patients and will consider nephrectomy only if they develop hypertension or recurrent urinary tract infection.

–In this technique, the obstructed segment is completely resected, the renal pelvis is tapered with reanastomosis of the renal pelvis and ureter in a dependent funneled fashion.

–The decision of whether to use a ureteral stent transiently is still controversial.

–Pyeloplasty can be performed through one of these approaches:

•A flank, dorsal lumbotomy

•An anterior extraperitoneal approach

•Laparoscopic pyeloplasty

•Robotic assisted pyeloplasty

–The success rate of open Anderson-Hynes dismembered pyeloplasty for treating PUJ obstruction exceeds 95 %.

–There are those who use ureteral stents routinely.

–Others prefer using a double “J” stent.

–The use of perianastomotic drain following the repair is also controversial.

–The routine use of nephrostomy is also controversial.

–While open pyeloplasty is still considered the standard treatment of UPJ obstruction in infants, laparoscopic pyeloplasty, with or without robotic assistance, is the treatment of choice in older children and in most adults.

•Laparoscopic pyeloplasty:

–Traditionally, PUJ obstruction has been repaired with an open pyeloplasty.

–Laparoscopic pyeloplasty was first introduced in adults in 1993 by Schuessler.

Surgical Treatment for PUJ Obstruction

•Open pyeloplasty

•Laparoscopic pyeloplasty

•Percutaneous endopyelotomy

•Retrograde endopyelotomy

•Endopyeloplasty

•Robotic-assisted laparoscopic pyeloplasty

•Percutaneous balloon dilatation

•Endoscopic balloon dilatation

–The success of laparoscopic pyeloplasty is comparable with those of open pyeloplasty, with success rates reported to be as high as 96–98 %.

–Laparoscopic pyeloplasty is reported to be feasible and safe in children.

–Currently, laparoscopic pyeloplasty is performed for older children.

–It is technically unfeasible in very small children and infants because of space constraints.

–Laparoscopic pyeloplasty is a technically demanding procedure that generally requires significant laparoscopic experience.

–A small intrarenal pelvis is a relative contraindication to laparoscopic pyeloplasty.

–Laparoscopic pyeloplasty being a minimally invasive technique has several advantages including:

•Shorter hospital stay

•Faster recovery

•Decreased morbidity

•Better cosmetic result

•The success rates are comparable with those of open pyeloplasty

–Laparoscopic pyeloplasty is divided according to the approach into two types:

•Transperitoneal laparoscopic pyeloplasty

•Retroperitoneoscopic laparoscopic pyeloplasty

–Laparoscopic pyeloplasty can be offered to patients with:

•Severe hydronephrosis

•Aberrant crossing vessels

•Long-segment PUJ strictures

•Secondary PUJ obstruction

–The endoscopic incision should be performed full-thickness through the PUJ and into perirenal fat.

–To ensure a proper adequate incision, extravasation of contrast should be seen on pyelography during the procedure.

–Most surgeons dilate the newly incised area with a balloon catheter to help ensure a complete incision.

–This is followed by prolonged ureteral stenting, for a period of 4–8 weeks. The stent help keeps the incised PUJ open and maintains renal drainage.

–Endopyelotomy is a reasonable option in patients with mild-to-moderate hydronephrosis and reasonably good renal function.

–The area of stricture should be short (<1.5 cm), and no crossing vessels should be defined on preoperative or intraoperative imaging.

–Endopyelotomy is also particularly useful following a failed open or laparoscopic pyeloplasty.

–The success rates with the percutaneous and ureteroscopic endopyelotomy are 80–90 %.

•Endopyeloplasty:

–This was first reported in 2002 by Gill et al from the Cleveland clinic.

–The procedure is performed through a percutaneous tract via a 26 F nephroscope.

–It consists of horizontal suturing of a standard vertical endopyelotomy incision.

–Indications for endopyeloplasty include:

•A short-segment PUJ obstruction

•Absence of crossing renal polar vessels

•No prior surgery in the PUJ.

–The results of endopyeloplasty are comparable to those of endopyelotomy.

•Ureterocalicostomy:

–A partial nephrectomy is performed and the ureter is anastomosed to a lower-pole renal calyx.

–This is usually reserved for patients following a failed open pyeloplasty when no extrarenal pelvis and significant hilar scarring are present.

• Balloon dilatations of PUJ obstruction (Figs. 3.47 and 3.48):

–Balloon dilatation of PUJ obstruction was first done in 1982 by Kadir et al in 1982.

–Balloon dilatation can be done antegrade, retrograde or combined and the success rate is variable.

–Percutaneous or endoscopic balloon dilatation of PUJ is another alternative to treat PUJ obstruction in children.