Is ureteroscopy indicated for an impacted 4 × 3 mm distal ureteric stone causing mild hydroureteronephrosis, and can the concurrent 3 × 3 mm non‑obstructive stone in the left upper renal calyx be treated at the same time?

Ureteroscopy is Indicated for This Impacted Distal Ureteric Stone

Yes, ureteroscopy is indicated for the 4 × 3 mm impacted distal ureteric stone causing mild hydroureteronephrosis, and the concurrent 3 × 3 mm upper calyceal stone can be treated during the same procedure.

Primary Indication: The Impacted Distal Stone

The key factor here is stone impaction with associated obstruction (hydroureteronephrosis), not just stone size. While a 4 mm stone would typically be managed conservatively with medical expulsive therapy for up to 4-6 weeks 1, the presence of impaction fundamentally changes management:

• Impacted stones are high-risk for ureteral stricture development and require more aggressive intervention 2
• The stone's location at the distal ureteric orifice with documented obstruction (hydroureteronephrosis) indicates it is unlikely to pass spontaneously
• Ureteroscopy for distal ureteral stones achieves 94% stone-free rates with rigid/semirigid ureteroscopes 3
• Complication rates are low (<5% perforation, <2% stricture) 3

The Concurrent Renal Stone

The 3 × 3 mm non-obstructive upper calyceal stone should be treated simultaneously during the same ureteroscopic session:

• Treating both stones in one procedure avoids a second anesthetic exposure and reduces overall healthcare burden
• While this stone is small and non-obstructive, addressing it prevents future symptomatic episodes
• Flexible ureteroscopy can access the upper calyx after treating the distal stone 3
• The evidence supports treating concurrent stones when technically feasible 4, 5

Procedural Approach

Use a semirigid ureteroscope for the distal stone, then flexible ureteroscopy for the renal stone:

1. Start with the impacted distal stone using semirigid ureteroscopy with holmium laser lithotripsy
2. Place a safety guidewire before proceeding 6
3. After clearing the distal stone, advance a flexible ureteroscope to the upper calyx to treat the 3 mm stone
4. Consider postoperative stenting given the impacted nature of the distal stone, which increases stricture risk 2

Important Caveats

• Impacted stones require careful technique to avoid ureteral injury during manipulation 7, 8
• The ureteral wall thickness on imaging may predict difficulty—if >1.9 mm, expect more challenging dissection 8
• Do not attempt conservative management for impacted stones causing obstruction, as this risks progressive renal damage
• If the patient had signs of infection, urgent drainage would be required before definitive stone treatment 9

Why Not Conservative Management?

Conservative management with medical expulsive therapy (alpha-blockers) is inappropriate here because:

• The stone is impacted (not just present in the ureter)
• There is documented obstruction (hydroureteronephrosis)
• Impacted stones have significantly lower spontaneous passage rates
• The risk of ureteral stricture increases with prolonged impaction 2

Bottom line: Proceed with ureteroscopy to treat both stones in a single session, using semirigid technique for the distal stone and flexible ureteroscopy for the renal stone, with strong consideration for temporary ureteral stenting given the impaction.