Can a non-obstructing ureteric stone measuring 29x26x24 mm pass spontaneously or should it be referred for surgical intervention?

Management of Non-Obstructing Ureteric Stone Measuring 29x26x24 mm

Surgical intervention is strongly recommended for a non-obstructing ureteric stone measuring 29x26x24 mm as spontaneous passage is extremely unlikely for stones of this size. 1

Stone Size and Likelihood of Spontaneous Passage

• Spontaneous passage rates are directly related to stone size:

  • Stones ≤5 mm: 68% pass spontaneously 1
  • Stones >5 mm and ≤10 mm: 47% pass spontaneously 1
  • Stones >10 mm: Extremely low likelihood of spontaneous passage

• At 29x26x24 mm, this stone is significantly larger than the threshold for spontaneous passage:

  • The American Urological Association (AUA) guidelines indicate that even stones >10 mm have poor spontaneous passage rates 1
  • This stone is nearly three times larger than the upper limit for which spontaneous passage is even considered possible

Recommended Management Approach

1. Surgical Intervention Options

• Ureteroscopy with laser lithotripsy:

  • First-line treatment for large ureteric stones 1
  • High success rates (stone-free rates of 81-94% depending on stone location) 1
  • Minimally invasive approach with shorter recovery time

• Percutaneous Nephrolithotomy (PCNL):

  • Indicated for stones >20 mm 2
  • Given the large size of this stone (29x26x24 mm), PCNL may be appropriate

• Laparoscopic ureterolithotomy:

  • May be considered for large, hard, and chronically impacted stones 3
  • Reported success rates of 96% for large ureteric stones 3

2. Pre-Surgical Considerations

• Obtain low-dose CT scan for precise stone characterization 1
• Assess for signs of infection or obstruction development
• Evaluate renal function to establish baseline
• Consider antibiotic prophylaxis for the procedure 2

Rationale Against Watchful Waiting

• Stone size of 29x26x24 mm far exceeds the threshold for spontaneous passage
• Even with medical expulsive therapy (MET), stones >10 mm have minimal chance of spontaneous passage 1
• Waiting for spontaneous passage of a stone this size risks:
  • Development of obstruction
  • Renal function deterioration
  • Infection and sepsis
  • Chronic pain

Special Considerations

• If the stone is currently non-obstructing but causing symptoms:

  • Surgical intervention is still recommended due to the extremely low likelihood of spontaneous passage
  • Risk of developing obstruction over time is significant

• If the patient has bleeding diatheses or requires continuous anticoagulation:

  • Ureteroscopy should be considered first-line therapy as it can be safely performed in these patients 1

• If the stone is asymptomatic and incidentally found:

  • Surgical intervention is still recommended due to the high risk of future complications with a stone of this size 1, 2

Follow-up After Treatment

• Post-procedure imaging to confirm stone clearance
• Metabolic evaluation to identify risk factors for recurrence
• Stone analysis to guide preventive measures

Common Pitfalls to Avoid

• Delaying intervention for large stones in hopes of spontaneous passage
• Underestimating the risk of complications from large ureteric stones
• Failing to adequately prepare patients for the likelihood of surgical intervention

In conclusion, a non-obstructing ureteric stone measuring 29x26x24 mm requires surgical intervention rather than observation for spontaneous passage, with ureteroscopy with laser lithotripsy or PCNL being the most appropriate options based on current guidelines.