Multiphysics Analysis of Ultrasonic Shock Wave Lithotripsy and Side Effects on Surrounding Tissues

Area of Science:

• Acoustics
• Biomedical Engineering
• Computational Physics

Background:

• Extracorporeal shock wave lithotripsy is the standard kidney stone treatment.
• Previous numerical studies often omit dissipation phenomena.
• This research incorporates nonlinear acoustics and dissipation into simulations.

Purpose of the Study:

• Compare linear and nonlinear acoustic models for shock wave lithotripsy simulation.
• Analyze the influence of shock wave profiles and stone composition on fragmentation.
• Investigate potential side effects on surrounding kidney tissues.

Main Methods:

• Utilized COMSOL Multiphysics for computational modeling.
• Employed the finite element method.
• Coupled and solved nonlinear governing equations for acoustics, elasticity, and bioheat transfer.

Main Results:

• Shorter shock wave rise times increase acoustic pressure and focal region size.
• Both linear and nonlinear models show kidney tissue damage.
• Temperature-induced damage is minimal compared to High Intensity Focused Ultrasound (HIFU).

Conclusions:

• Ignoring wave nonlinearity leads to unrealistic simulation outcomes.
• Kidney stone material is a critical factor in fragmentation efficiency.
• Nonlinear acoustic modeling provides a more accurate representation of lithotripsy.