Shock wave lithotripsy correlates with stone density on preoperative computerized tomography.

Area of Science:

• Urology
• Nephrology
• Medical Imaging

Background:

• Shock wave lithotripsy (SWL) is a common treatment for kidney stones.
• Predicting SWL success is crucial for patient management and resource allocation.

Purpose of the Study:

• To evaluate the stone-free rate using the Dornier Doli S lithotriptor.
• To determine if preoperative computed tomography (CT) Hounsfield density can predict SWL outcomes.

Main Methods:

• Retrospective review of 76 patients with solitary urinary calculi (5-20 mm).
• Pretreatment noncontrast CT assessed Hounsfield density.
• Outcomes (stone-free, residual fragments, unchanged stone) assessed at 12 weeks.

Main Results:

• Overall stone-free rate was 37%.
• Stones with lower Hounsfield density (<1000 HU) had a higher stone-free rate (46%) compared to denser stones (17%).
• Median density of stone-free patients' calculi was significantly lower (684 HU) than those with residual fragments or unchanged stones.

Conclusions:

• The Dornier Doli S lithotriptor demonstrated a lower-than-expected stone-free rate.
• Preoperative CT Hounsfield density is a significant predictor of SWL success.
• Patients with stones >1000 HU should be counseled regarding lower success rates and potential need for auxiliary procedures.