What is the recommended treatment for an 11-year-old female with recurrent abdominal pain, vomiting, and a CT scan suggesting post-operative hydronephrosis due to Pelvic-Ureteric Junction (PUJ) obstruction?

Management of Post-Operative Hydronephrosis Due to PUJ Obstruction in an 11-Year-Old Female

For an 11-year-old female with recurrent abdominal pain, vomiting, and CT evidence of post-operative hydronephrosis due to pelvic-ureteric junction (PUJ) obstruction, surgical intervention with pyeloplasty is the recommended definitive treatment. 1

Diagnostic Evaluation

• Initial assessment should include renal ultrasound to confirm hydronephrosis severity, evaluate renal parenchymal thickness, and assess for hydroureter or other urinary tract abnormalities 1
• MAG3 renal scan is indicated to evaluate:
  • Split renal function (differential function between kidneys)
  • Degree of obstruction
  • Drainage patterns 1
• MAG3 is preferred over DTPA scan due to its higher extraction fraction (40-50% vs 20%), resulting in better image quality and more accurate assessment of obstruction 1

Severity Assessment

• The severity of hydronephrosis should be graded using either:
  • Society for Fetal Urology (SFU) grading system (grades 1-4)
  • Anterior-posterior renal pelvic diameter (APRPD) measurement 1
• Moderate to severe hydronephrosis (SFU grade 3-4 or APRPD >15mm) with symptoms indicates significant obstruction requiring intervention 1

Treatment Options

Surgical Management

• Anderson-Hynes dismembered pyeloplasty is the gold standard surgical treatment with success rates exceeding 90% 2, 3
• Surgical approaches include:
  • Open pyeloplasty - traditional approach with excellent outcomes
  • Laparoscopic pyeloplasty - less invasive with comparable success rates (91.6%) 2
  • Robot-assisted laparoscopic pyeloplasty - emerging option with good outcomes 3

Temporary Decompression

• In cases of severe obstruction with infection or significantly impaired renal function, temporary decompression may be needed before definitive repair:
  • Percutaneous nephrostomy (PCN) - provides immediate drainage 1
  • Retrograde ureteral stenting - may be considered but can be technically challenging in children 1

Special Considerations

• Crossing vessels should be evaluated as a potential cause of PUJ obstruction:
  • Present in approximately 50% of cases 2
  • Requires specific surgical approach (transposition or division of vessels) 4, 5
• Post-operative PUJ obstruction may represent:
  • Inadequate initial repair
  • Stricture formation
  • Persistent anatomical factors 5, 6

Follow-Up Protocol

• Post-surgical monitoring should include:
  • Ultrasound at 1-6 months post-procedure 1
  • MAG3 renal scan to evaluate improvement in drainage and function 1
  • Clinical assessment for resolution of symptoms (abdominal pain, vomiting) 1

Surgical Success Criteria

• Resolution of symptoms (abdominal pain, vomiting)
• Improved drainage on imaging studies
• Preservation or improvement of renal function (differential function >40%)
• No recurrence of obstruction 1, 5

Potential Complications

• Persistent urine leak
• Anastomotic stricture recurrence
• Bleeding
• Infection 2

In this case, given the recurrent symptoms and CT evidence of post-operative hydronephrosis, the patient likely requires surgical revision of the PUJ obstruction to relieve symptoms and preserve renal function.