Development of a dynamic model for bevel-tip flexible needle insertion into soft tissues

Area of Science:

• Robotics and Biomechanics
• Medical Device Engineering
• Computational Mechanics

Background:

• Accurate modeling of flexible needle insertion is crucial for minimally invasive surgery.
• Bevel-tip asymmetry significantly influences needle trajectory in soft tissues.
• Existing models often lack comprehensive consideration of dynamic forces and tissue interactions.

Purpose of the Study:

• To develop a mechanics-based dynamic model for bevel-tip flexible needle insertion into soft tissues.
• To predict needle deflections considering actuation, friction, tissue interactions, and bevel-tip forces.
• To validate the model through experimental comparison with simulations.

Main Methods:

• Newton-Euler formulation for dynamic modeling of needle insertion.
• Finite element analysis (FEA) for simulating soft tissue deformation.
• Integration of a mechanics-based model to predict bevel-tip induced deflections.
• Experimental validation using a tissue phantom and varying insertion depths.

Main Results:

• The developed model accurately predicts needle deflections during insertion into soft tissues.
• Bevel-tip asymmetry was identified as a key factor influencing needle path.
• Simulated deflections closely matched experimental results across different insertion depths.

Conclusions:

• The mechanics-based dynamic model provides a robust tool for simulating flexible needle insertion.
• This model enhances the understanding of needle-tissue mechanics and aids in surgical planning.
• The findings support the development of more precise robotic surgical instruments.