A 15-year-old girl has episodic left loin pain, typically provoked by heavy fluid intake. Ultrasound shows left hydronephrosis with a normal calibre ureter. A MAG3 diuretic renogram shows preserved differential function of 45% on the left with delayed tracer washout, half time exceeding 30 minutes after furosemide. What is the most appropriate definitive management?

• A Anderson-Hynes dismembered pyeloplasty ✓
• B Percutaneous nephrostomy as definitive treatment
• C Antegrade balloon dilatation of the pelviureteric junction
• D Long term alpha blocker therapy

Explanation

Symptomatic pelviureteric junction obstruction with objective impairment of drainage on a diuretic renogram warrants surgical correction. The Anderson-Hynes dismembered pyeloplasty remains the gold standard, excising the aperistaltic segment and creating a dependent funnel-shaped anastomosis, with success rates above 90%. Percutaneous nephrostomy is a temporising measure, balloon dilatation gives inferior long-term patency, and alpha blockers have no role in a mechanical anatomical obstruction.

Reference: Campbell-Walsh Urology, 12th ed.

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Written and medically reviewed by the StethoPrep medical team.