Physics of ultrasonic surgery using tissue fragmentation: Part I

Area of Science:

• Biomedical Engineering
• Surgical Technology
• Acoustic Physics

Background:

• The precise mechanism of ultrasonic surgical aspirators (USAs) in tissue fragmentation is not fully understood.
• Current understanding suggests cavitation and mechanical actions are involved, but their interplay requires further investigation.
• Optimizing USA performance necessitates a clearer understanding of how operational parameters influence tissue interaction.

Purpose of the Study:

• To examine the influence of stroke, suction, frequency, tissue type, and tip area on tissue fragmentation rate using USAs.
• To develop a quantitative method for assessing USA performance across different tissue types.
• To investigate the acoustic pressures and powers at the USA tip through thermal and load experiments.

Main Methods:

• Experimental analysis of USA parameters including stroke, suction, frequency, and tip area.
• Development and application of a novel tissue quantifier for performance assessment.
• Thermal and tip load experiments to estimate acoustic parameters at the vibrating tip.
• Photographic and acoustic data collection during experiments in water and fresh pig tissues.

Main Results:

• Suction was identified as a significant factor contributing to the tissue fragmentation interaction.
• A quantitative method was developed to correlate USA performance with specific tissue types.
• Acoustic pressures and powers at the tip were estimated using thermal and load measurements.
• Fragmentation effects were further analyzed using photographic and acoustic data in various media.

Conclusions:

• Suction plays a critical role in the efficacy of ultrasonic surgical aspiration.
• The developed tissue quantifier provides a valuable tool for evaluating USA performance.
• Further investigation using photographic and acoustic data enhances the understanding of fragmentation mechanisms.