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Control of soft tissue deformation during robotic needle insertion
Niki Abolhassani1, Rajni Patel, Mehrdad Moallem
1Department of Electrical and Computer Engineering, University of Western Ontario, London, Canada. nabolhas@uwo.ca
Summary
This study explored robot-assisted needle insertion trajectories to minimize tissue deformation during percutaneous therapies. Axial rotation and force feedback controllers significantly reduce tissue indentation and friction for improved accuracy.
Area of Science:
- Robotics and Medical Devices
- Biomedical Engineering
- Surgical Simulation
Background:
- Accurate needle insertion is critical for percutaneous therapies, especially in procedures like prostate brachytherapy requiring multiple insertions.
- Minimizing tissue deformation before and during needle insertion is essential to maintain accuracy and reduce patient trauma.
- Existing methods may not adequately address the dynamic challenges of soft, inhomogeneous tissue manipulation.
Purpose of the Study:
- To investigate the impact of different robotic trajectories on minimizing tissue deformation during needle insertion.
- To identify optimal parameters for robotic needle insertion to reduce indentation and frictional forces.
- To evaluate a novel position/force controller for enhanced precision in percutaneous procedures.
Main Methods:
- Utilized a 2-DOF (degrees of freedom) robot to perform needle insertions into soft, inhomogeneous tissue models.
- Compared tissue indentation and frictional forces across various needle insertion trajectories.
- Developed and tested an infinitesimal force per tissue displacement parameter for online trajectory adjustments.
- Implemented and assessed a position/force controller designed to minimize pre-puncture tissue deformation.
Main Results:
- Identified infinitesimal force per tissue displacement as a valuable metric for real-time trajectory optimization.
- Demonstrated that axial rotation of the needle significantly reduces both pre-puncture tissue indentation and post-puncture frictional forces.
- The proposed position/force controller achieved substantial improvements in minimizing tissue deformation prior to needle puncture.
Conclusions:
- Optimized robotic trajectories, particularly those incorporating axial rotation, can effectively reduce tissue deformation during needle insertion.
- The developed position/force control strategy offers a promising approach for enhancing the precision and safety of robotic percutaneous therapies.
- Further research into force feedback and trajectory planning can lead to more accurate and less invasive medical procedures.