How to manage stone intrusion and extrusion during Ureteroscopic Lithotripsy (URSL) and its complications?

Management of Stone Intrusion and Extrusion During Ureteroscopic Lithotripsy

Immediate Intraoperative Management

When stone retropulsion (proximal migration) occurs during URSL, maintain a safety guidewire in place, consider using anti-retropulsion devices or polymeric gels, and be prepared to convert to alternative approaches including staged procedures or percutaneous access. 1

Prevention Strategies

• Always use a safety guidewire during ureteroscopic procedures to facilitate rapid re-access if the primary working wire is lost and to provide access in cases of collecting system injury 1

• Anti-retropulsion devices such as polymeric gels (e.g., BackStop) can be deployed distal to the stone before lithotripsy to prevent proximal fragment migration, with studies showing 100% success in preventing retropulsion without complications 2

• Avoid electrohydraulic lithotripsy (EHL) as first-line for intracorporeal lithotripsy due to its propensity to damage ureteral mucosa and cause perforation 1

• Select appropriate ureteral access sheaths as different sheaths affect ureteroscope maneuverability and stone extraction efficiency 3

Managing Stone Retropulsion

When stones migrate proximally during lithotripsy:

• For upper ureteral migration: Consider aborting the procedure and treating with extracorporeal shock wave lithotripsy (SWL) after placement of a ureteral stent, or proceed with flexible ureteroscopy if equipment and expertise allow 4

• For impacted stones: Pass a rigid ureteroscope to the stone, perform disimpaction using laser fragmentation or other dislodgement maneuvers, then treat proximal stones or large fragments with SWL 4

• Antegrade percutaneous approach: For upper ureteral stones with significant retropulsion, antegrade percutaneous ureterolithotripsy achieves superior stone-free rates (93.75% vs 81.13%) compared to retrograde URSL, though with higher minor complication rates 5

Managing Stone Extrusion (Fragment Impaction)

Residual Fragment Management

• Offer endoscopic procedures to render patients stone-free when residual fragments are present, especially if infection stones are suspected, as 29% of patients with residual fragments require subsequent intervention 1

• For impacted lower ureteral fragments: Fragment in situ with extraction of hard fragments by basket; alternative treatments include unstented in situ SWL or, rarely, open surgery 4

• Send stone material for analysis to guide future prevention strategies 1

Special Circumstances

• If purulent urine is encountered: Immediately abort the procedure, establish drainage with a ureteral stent or nephrostomy tube, obtain urine culture, and continue broad-spectrum antibiotics 1

• For obstructing stones with suspected infection: Urgently drain the collecting system before attempting definitive stone treatment to allow drainage of infected urine and antibiotic penetration 1

Complications and Their Management

Major Complications

Ureteral injury (perforation, avulsion) occurs in 3-9% of cases:

• Maintain safety guidewire access 1
• Place ureteral stent for 2-6 weeks
• Consider nephrostomy tube for major perforations
• Delayed recognition can lead to rare complications like ureterovaginal fistula from impacted fragments 6

Sepsis (2-5% incidence):

• Administer antimicrobial prophylaxis within 60 minutes of procedure based on prior urine cultures and local antibiogram 1
• Abort procedure if purulent urine encountered 1
• Ensure adequate drainage before stone treatment 1

Steinstrasse (stone street formation, 0-10% incidence):

• More common with SWL than URS 1
• May require secondary procedures including repeat URS or SWL 1

Minor Complications

Ureteral stricture (1-7% incidence):

• Higher risk with EHL compared to laser lithotripsy 1
• May require delayed reconstruction 1

Stent-related symptoms:

• Consider alpha-blockers and anti-muscarinic therapy to reduce discomfort 1
• Routine stenting after uncomplicated URS is optional 1

Algorithm for Failed Stone Extraction

1. Initial attempt fails due to retropulsion: Deploy anti-retropulsion device if available, or place stent and stage procedure 2, 4

2. Stone migrates to kidney: Consider flexible ureteroscopy in same sitting if available, otherwise stage with SWL or repeat URS 4, 5

3. Persistent failure with retrograde approach: Offer antegrade percutaneous approach for upper ureteral stones 10-20mm, which achieves 93.75% stone-free rates 5

4. Complex anatomy or large stone burden: Reserve open/laparoscopic/robotic surgery for rare cases with anatomic abnormalities requiring concomitant reconstruction 1

Critical Pitfalls to Avoid

• Never proceed without a safety guidewire as this compromises ability to manage complications 1
• Do not use EHL as first-line lithotripsy due to high mucosal injury risk 1
• Do not continue procedure if purulent urine is encountered - this risks severe sepsis and mortality 1
• Do not leave infection stone fragments as they promote recurrent UTI, stone growth, and renal damage 1