Modelling of non-linear elastic tissues for surgical simulation

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Surgical Simulation

Background:

• High-fidelity surgical simulators require realistic modeling of instrument-organ interactions.
• Previous real-time simulations often used linear elastic models for tissues due to computational constraints.
• Human soft tissues exhibit non-linear properties, which linear models do not fully capture.

Purpose of the Study:

• To investigate the impact of non-linear tissue properties, specifically the Poynting effect, on force perception in surgical simulation.
• To compare the significance of the Poynting effect in different tissue types.

Main Methods:

• Utilized constitutive equations for non-linear tissue models.
• Conducted experiments to validate model predictions.
• Analyzed the Poynting effect's contribution to normal forces during shearing.
• Compared calculated force differences with human perception thresholds for force discrimination.

Main Results:

• The Poynting effect, inherent in non-linear models, generates normal forces absent in linear elastic models.
• This effect leads to force magnitude differences exceeding human perception thresholds in myocardial tissues.
• The Poynting effect's impact on force perception was less pronounced in brain tissue simulants.

Conclusions:

• Non-linear tissue modeling, accounting for the Poynting effect, is essential for accurate surgical simulation.
• The Poynting effect's influence on force feedback varies significantly across different tissue types.
• Accurate force feedback in surgical simulators necessitates incorporating non-linear material properties.