How do ureteral stone size and symptoms guide management and treatment?

Management of Ureteral Stones Based on Size and Symptoms

For ureteral stones, management should be guided primarily by stone size, with stones <10 mm often suitable for observation and medical expulsive therapy, while stones >10 mm typically require surgical intervention such as ureteroscopy or shock wave lithotripsy. 1, 2

Stone Size and Spontaneous Passage Rates

• Stones <4 mm have excellent spontaneous passage rates of approximately 98%, making observation the preferred initial approach 3
• Stones 4-5 mm have moderate spontaneous passage rates (81% for 4 mm, 65% for 5 mm) and may benefit from medical expulsive therapy 3
• Stones 6 mm have lower spontaneous passage rates (33%), while stones ≥6.5 mm have poor spontaneous passage rates (9%) 3
• The 10 mm threshold is recognized by major guidelines as the key decision point between conservative and surgical management 1, 2

Initial Management of Stones <10 mm

• For stones <10 mm with controlled symptoms, observation with periodic evaluation is an appropriate initial treatment option 1, 2
• Medical expulsive therapy (MET) with alpha-blockers significantly improves stone-free rates for distal ureteral stones <10 mm (77.3% vs 54.4% with placebo) 2
• Patient selection criteria for observation/MET:
  • Well-controlled pain
  • No clinical evidence of sepsis
  • Adequate renal functional reserve 1, 2

Follow-up During Conservative Management

• Patients should be monitored with periodic imaging studies to assess stone position and hydronephrosis 1, 2
• Maximum duration for conservative therapy should be limited to 4-6 weeks from initial presentation to avoid kidney injury 1, 2
• Patients should be counseled that alpha-blockers are used "off-label" for MET and informed about potential side effects 1, 2

Management of Stones >10 mm

• Stones >10 mm typically require surgical intervention in most cases 1, 2
• Both shock wave lithotripsy (SWL) and ureteroscopy (URS) are acceptable first-line treatments 1
• URS yields significantly greater stone-free rates with a single procedure but has slightly higher complication rates compared to SWL 1
• Complication rates for URS include:
  • Ureteral injury: 3-6% (depending on stone location)
  • Stricture formation: 1-4%
  • Sepsis: 2-4% 1, 2

Location-Specific Considerations

• For distal ureteral stones <10 mm:

  • Medical expulsive therapy is particularly effective 2
  • If intervention is needed, both URS and SWL are effective options 1

• For proximal ureteral stones <10 mm:

  • URS is recommended as first-line treatment by AUA/ES guidelines
  • SWL is considered an equivalent option by EAU and SIU/ICUD guidelines 1

• For proximal ureteral stones >10 mm:

  • URS is generally recommended as first-line treatment
  • SWL may be considered but has lower success rates for larger stones 1

Preoperative Evaluation

• Non-contrast CT scan should be obtained prior to surgical intervention 1
• Urinalysis is required before any intervention; urine culture should be obtained if infection is suspected 1, 2
• CBC, platelet count, serum electrolytes and creatinine should be obtained if there is risk of hemorrhage or suspicion of reduced renal function 1

Pain Management During Conservative Treatment

• NSAIDs (e.g., diclofenac, ibuprofen) are recommended as first-line analgesics for renal colic 2, 4
• Opioids should be used as second-line therapy only if NSAIDs are contraindicated or insufficient 2

When to Escalate Care

• Immediate reassessment is required if:
  • Symptoms worsen
  • Fever develops
  • Evidence of obstruction increases 2
• If conservative management fails, surgical intervention should be considered based on stone size and location 1