From the Guidelines
A 9.5 mm left-sided lower calyceal stone is not the ideal candidate for Extracorporeal Shock Wave Lithotripsy (ESWL) due to its size and location, and ureteroscopy with laser lithotripsy is generally preferred as the first-line treatment. According to the EAU guidelines, active surveillance is acceptable for stones up to 15 mm, but for lower pole stones between 10 and 20 mm, fURS and PCNL are suggested options 1. Although SIU/ICUD guidelines recommend treating lower pole renal stones with SWL as the first choice for stones less than 15 mm, the success rate of ESWL for lower calyceal stones is reduced due to gravity-dependent position and challenging fragment passage.
Some key points to consider when evaluating the suitability of ESWL for this patient include:
- Stone size: The 9.5 mm stone size reduces ESWL success rates, as stones larger than 1 cm generally respond less favorably to shock wave therapy.
- Stone location: Lower calyceal stones have reduced clearance rates with ESWL compared to stones in other locations.
- Patient-specific factors: Skin-to-stone distance, stone density, and lower pole anatomy further influence success rates. If ESWL is still pursued, patients should be informed about the lower success rate and potential need for additional procedures, and post-procedure recommendations would include adequate hydration, possible alpha-blockers, and appropriate pain management 1.
From the Research
Indications for ESWL
- A 9.5 mm left-sided lower calyceal stone may be indicated for Extracorporeal Shock Wave Lithotripsy (ESWL) based on stone size and location.
- Studies have shown that ESWL is effective for smaller stones, typically less than 2 cm in size 2, 3, 4.
- However, the success rate of ESWL for lower pole stones is generally lower compared to other locations, such as the upper or middle calyces 2, 3.
Comparison with Other Treatments
- Percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) are alternative treatments for kidney stones, particularly for larger stones or those in difficult locations 5, 2, 3, 4.
- PCNL has been shown to have a higher stone-free rate and efficiency quotient (EQ) compared to ESWL for lower pole stones, but may have a higher complication rate 2, 3.
- RIRS, also known as flexible ureteroscopy, has been shown to have comparable stone-free rates to PCNL and higher than ESWL for lower pole stones, with potentially lower complication rates 4.
Specific Study Findings
- A study comparing ESWL to PCNL for lower pole stones found that PCNL had a higher stone-free rate (83% vs 51%) and EQ (76% vs 44%) 3.
- Another study comparing ESWL to RIRS and mini PCNL for lower pole stones found that RIRS and mini PCNL had higher stone-free rates (90.2% and 90.5%, respectively) compared to ESWL (61.5%) 4.