Why is a stent placed after lithotripsy?

Stent Placement After Lithotripsy: Indications and Rationale

Stents after lithotripsy are not routinely necessary but should be placed in specific situations including trauma to the ureter, residual stone fragments, bleeding, perforation, urinary tract infection, or pregnancy to prevent complications and ensure proper urinary drainage. 1

Purpose of Stent Placement

Ureteral stents serve several important functions following lithotripsy:

1. Prevention of Steinstrasse: Stents help reduce the risk of "steinstrasse" (stone street), a complication where multiple stone fragments line up in the ureter causing obstruction 1

2. Management of Ureteral Trauma: When lithotripsy causes trauma to the ureter, stenting helps maintain patency during healing 1

3. Facilitation of Fragment Passage: In cases with residual fragments, stents can help with their passage 2

4. Urinary Drainage: Ensures proper drainage when there is edema, bleeding or perforation 1

When Stent Placement is Indicated

According to the European Association of Urology guidelines, stent placement is specifically recommended in the following scenarios:

• Ureteral trauma during the procedure
• Residual stone fragments remaining after lithotripsy
• Bleeding during or after the procedure
• Ureteral perforation
• Urinary tract infection
• Pregnancy 1

When Stent Placement is NOT Necessary

• Uncomplicated procedures: Routine post-URS (ureteroscopy) stenting is unnecessary after uncomplicated procedures and may actually increase morbidity 1
• Small stones (<10mm) without complications during removal 3, 4, 5
• Holmium laser lithotripsy cases without complications or balloon dilation 4

Stent-Related Considerations

Benefits of Stenting

• Reduces risk of emergency department visits (10% in stented vs 20% in unstented patients) 3
• Decreases need for narcotic analgesics in the first 5 days post-procedure 3

Drawbacks of Stenting

• Irritative symptoms: Up to 93% of patients with stents experience irritative bladder symptoms compared to only 13.3% of unstented patients 3, 5
• Longer operative time: Stent placement adds approximately 13 minutes to the procedure 3
• Need for second procedure: Stent removal requires an additional cystoscopic procedure 1
• Increased discomfort: Patients with stents report greater flank pain, abdominal pain, dysuria and frequency in the first week 4

Improving Stent Tolerability

• Alpha-blockers can improve stent tolerability and should be prescribed when stents are placed 1
• Anti-muscarinics may also help relieve stent-related symptoms 1

Special Considerations

For ESWL (Extracorporeal Shock Wave Lithotripsy)

• Routine stenting before ESWL does not improve stone-free rates but may reduce steinstrasse 1
• For renal stones <2.5 cm, placement of a DJ stent for improving stone-free rate or enhancing fragment passage is generally unnecessary 2

For URS (Ureteroscopy)

• Prestenting has been shown to improve outcomes, particularly for renal stones 1
• Post-URS stenting should be selective rather than routine 1

Clinical Pitfalls to Avoid

1. Unnecessary stenting: Avoid routine stenting after uncomplicated procedures as it increases patient discomfort without clinical benefit

2. Failure to stent when indicated: Not placing a stent when there is ureteral trauma, residual fragments, or other indications can lead to obstruction and renal damage

3. Prolonged stent duration: Stents should be removed as soon as clinically appropriate to minimize irritative symptoms and encrustation

4. Neglecting symptom management: Always prescribe alpha-blockers when placing stents to improve patient comfort

By following these evidence-based guidelines for stent placement after lithotripsy, clinicians can optimize patient outcomes while minimizing unnecessary discomfort and procedures.