Is shockwave lithotripsy right for your stone?

Why candidacy matters

Shockwave lithotripsy is non-invasive and, for the right stone, highly effective. But its success depends heavily on a few measurable factors — mainly the stone's size, density, and location. A urologist who offers ESWL to everyone produces worse outcomes than one who selects carefully. Our approach is to match the treatment to the stone, not the other way around.

Factors that favor shockwave lithotripsy

• Stone size. Generally up to about 20 mm for kidney stones and up to 10 mm for stones in the lower (distal) ureter. The 2026 American Urological Association guideline lists ESWL as an option, alongside ureteroscopy, for distal ureteral stones ≤10 mm and proximal ureteral stones under 2 cm.
• Stone density. Softer stones fragment more easily. Density is measured in Hounsfield units (HU) on a non-contrast CT scan. In one prospective study, stones under 970 HU were cleared about 96% of the time after a single session, versus about 38% for denser stones — which is why we look closely at your CT before recommending ESWL.
• Stone location. Stones in the renal pelvis, upper or middle calyx, and the proximal or distal ureter tend to do well. The lower-pole calyx is a known weaker spot for ESWL because fragments drain less easily from there.
• Skin-to-stone distance. The shock wave has to travel from the skin to the stone. A shorter distance (generally under about 10–11 cm) transmits energy more efficiently; a larger body habitus can reduce effectiveness.
• No active infection, bleeding risk, pregnancy, or untreated blockage below the stone. These need to be addressed first, for safety.

When we recommend something else

Being honest about this is part of doing it well. We're more likely to steer you toward ureteroscopy or another approach when:

• The stone is very dense on CT (often the harder calcium oxalate monohydrate or brushite stones), where fragmentation is less reliable.
• The stone is cystine — these are characteristically hard and resistant to shockwaves.
• It sits in a lower-pole calyx with unfavorable drainage anatomy (a narrow or sharply angled infundibulum).
• Body habitus places the stone too deep for the shock wave to reach efficiently.
• Clearing the stone in a single session is your top priority — ureteroscopy generally has a higher stone-free rate per session, a trade-off we'll talk through with you.