Is a 7mm dense obstructive stone at the distal end of the left ureter causing moderate to severe left hydroureteronephrosis indicated for Extracorporeal Shock Wave Lithotripsy (ESWL)?

Management of 7mm Distal Ureteral Stone with Hydroureteronephrosis

For a 7mm dense obstructive stone at the distal end of the left ureter causing moderate to severe hydroureteronephrosis, ureteroscopy (URS) with laser lithotripsy is the preferred treatment over extracorporeal shock wave lithotripsy (ESWL). 1, 2

Treatment Options Based on Stone Location and Size

Distal Ureteral Stone Management:

• For stones >5mm in distal ureter:
  • URS is preferred due to higher stone-free rates (85-95%) with a single procedure 1, 2
  • ESWL has lower stone-free rates (74%) for distal ureteral stones 1

Key considerations for this 7mm stone:

1. Stone size: 7mm stones have poor spontaneous passage rates

   • Evidence shows stones ≥4mm in distal ureter typically require intervention 3
   • Spontaneous passage rates for stones >5mm and ≤10mm are only about 47% 2

2. Presence of obstruction: Moderate to severe hydroureteronephrosis indicates significant obstruction requiring prompt intervention

3. Stone-free rates by procedure:

   • URS: Higher stone-free rates for distal ureteral stones (94.6%) 4
   • ESWL: Lower stone-free rates for distal ureteral stones (74%) 1

Procedure-Specific Considerations

URS advantages:

• Higher single-procedure success rate
• Better visualization and direct stone fragmentation
• More effective for denser stones
• Can be performed as emergency procedure with 92.4% overall stone-free rate 4

ESWL limitations:

• Lower success rates for distal ureteral stones
• May require multiple sessions (average 1.38 procedures per patient for distal ureteral stones) 1
• Less effective for dense stones
• Stone-free rates have declined for distal ureteral stones compared to earlier studies 1

Complications Comparison

• URS: Slightly higher rates of ureteral injury (3-6%) 2
• ESWL: Lower rates of ureteral injury (1-2%) 2
• Both procedures have similar rates of sepsis (2-3%) and UTI (4%) 1

Important Clinical Pearls

1. Pre-procedure preparation:

   • Obtain urine culture prior to intervention
   • Administer appropriate antibiotics if infection is suspected 1

2. Procedural safety:

   • Blind basketing should never be performed (extraction without endoscopic visualization) 1
   • Consider using a ureteral access sheath during URS to facilitate multiple passes and reduce complications 5

3. Post-procedure monitoring:

   • Resolution of hydronephrosis is a better predictor of stone passage than resolution of pain 6
   • Follow-up imaging is essential to confirm stone clearance

Conclusion

For this specific case of a 7mm dense obstructive stone in the distal ureter causing moderate to severe hydroureteronephrosis, ureteroscopy with laser lithotripsy is the preferred first-line treatment based on higher stone-free rates and better efficacy for larger, denser stones in the distal ureter.