Ureteroscopic Management of Proximal Obstructing Ureteral Stones
When ureteroscopy reveals a proximal obstructing ureteral stone (POMU), proceed with ureteroscopic lithotripsy using holmium:YAG laser fragmentation, which achieves an 81% stone-free rate for proximal ureteral stones regardless of size. 1
Primary Treatment Approach
Flexible ureteroscopy with holmium laser lithotripsy is the recommended definitive treatment for proximal ureteral stones discovered during ureteroscopy, as this modality is now deemed appropriate for stones of any size in the proximal ureter. 1
Key Technical Considerations:
- Use flexible ureteroscopy over rigid/semirigid instruments for proximal stones, as flexible URS achieves superior stone-free rates (87% vs 77%) 1
- Holmium:YAG laser is the preferred lithotripsy device due to minimal tissue penetration and effectiveness across all stone compositions 1, 2
- Stone-free rates show minimal variation by size: 93% for stones ≤10 mm and 87% for stones >10 mm 1
Laser Settings Strategy
You have two effective approaches for laser lithotripsy:
Fragmentation with Extraction
- High energy, low frequency settings to create larger fragments for active basket retrieval 2
- Advantage: More complete initial stone clearance with active removal of all visible fragments 2
- Disadvantage: Slightly longer procedure time and marginally higher risk of ureteral injury 2
Dusting Technique
- Low energy, high frequency settings to create very small fragments that pass spontaneously 2
- Advantage: Shorter procedure times and lower risk of ureteral damage 2
- Disadvantage: Potential for residual stone debris if not all particles are expelled 2
Management of Impacted Stones
If the stone is impacted (common with chronic obstruction):
- Small caliber ureteroscopes (6.9-7.5Fr) with laser lithotripsy achieve 96-100% success rates for impacted stones 3
- Expect associated findings: inflammatory polyps (21%) and adjacent strictures (15%) 3
- Chronically impacted stones benefit from endoscopic lithotripsy as first-line therapy rather than repeated SWL attempts 3
Alternative Approaches for Specific Scenarios
When Retrograde Access Fails or Stone is Very Large (>15mm) and Impacted:
Consider percutaneous antegrade ureteroscopy for very large impacted proximal ureteral stones, which achieves 85-100% stone-free rates with acceptable complication rates comparable to other percutaneous procedures. 1
When Both URS and SWL Have Failed:
Laparoscopic ureterolithotomy is preferred over open surgery for very large, impacted, or multiple stones where endoscopic approaches have failed, though this is rarely necessary. 1
Critical Safety Points
- Complication rates for modern URS are low: ureteral perforation <5%, long-term stricture formation ≤2% 1
- Proper technique is more important than equipment for successful outcomes 1
- Stone displacement into the kidney can be managed using nitinol baskets (1.9-3.2Fr) to reposition stones into more favorable locations for fragmentation 4, 5