Improving Burst Wave Lithotripsy Effectiveness for Small Stones and Fragments by Increasing Frequency: Theoretical...

Area of Science:

• Biomedical Engineering
• Acoustic Physics
• Urology

Background:

• Kidney stones pose a significant clinical challenge.
• Current shock wave lithotripsy (SWL) methods face limitations in fragmenting smaller stones.
• Burst wave lithotripsy (BWL) offers a potential alternative for stone fragmentation.

Purpose of the Study:

• To investigate the fragmentation of small kidney stones using varying burst wave lithotripsy (BWL) frequencies.
• To understand the underlying physical mechanisms of BWL stone fragmentation.
• To optimize BWL parameters for efficient stone dust generation.

Main Methods:

• A linear elastic theoretical model was developed to predict stress within stones under BWL.
• Ex vivo experiments were conducted using human kidney stones (1-5 mm) treated with BWL at 390 kHz, 830 kHz, and a combination.
• Fragment size analysis was performed to quantify stone breakdown efficiency.

Main Results:

• Theoretical models predicted increased stress amplification within stones at higher BWL frequencies.
• Smaller stones (< threshold size) fragmented significantly faster at higher frequencies (p=0.0003).
• Larger stones were efficiently reduced to dust regardless of BWL frequency (low, high, or mixed).

Conclusions:

• Higher BWL frequencies can generate amplified stress, promoting the fragmentation of small kidney stones.
• BWL offers a frequency-dependent strategy for optimizing kidney stone treatment.
• The findings suggest BWL can efficiently fragment stones of all sizes into dust.