A 40-year-old woman presents with recurrent urinary tract infections and CT scan shows a horseshoe kidney with a 1.2 cm lower pole calculus. For stone fragmentation in a horseshoe kidney, which modality is least effective due to impaired drainage?
- A Ureteroscopic laser lithotripsy (URSL)
- B Extracorporeal shock wave lithotripsy (ESWL) ✓
- C Percutaneous nephrolithotomy (PCNL)
- D Robotic-assisted pyelolithotomy
Explanation
ESWL is the least effective modality for lower pole stones in horseshoe kidneys due to anatomically abnormal ureteropelvic junction (UPJ) position (anteromedially deviated), medial rotation of the kidneys, and the isthmus obstructing the ureter's dependent drainage — all impairing stone fragment passage after ESWL. Stone-free rates with ESWL in horseshoe kidneys are approximately 40–50% vs 70–80% for equivalent stones in normal kidneys. PCNL and URSL achieve superior stone-free rates (80–90%) in this anatomical variant, with PCNL being the procedure of choice for stones >2 cm.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.