Compensating for Torsion Windup in Steerable Needles.

Area of Science:

• Medical Devices
• Robotics
• Biomedical Engineering

Background:

• Flexible needles are used in medical procedures for steering and precise insertion.
• Tissue friction causes discrepancies between needle base and tip orientation, hindering control.
• Accurate needle tip alignment is crucial for minimally invasive surgery and targeted therapies.

Purpose of the Study:

• To develop and validate an algorithm for real-time alignment of flexible needles.
• To compensate for tissue-induced angle discrepancies during needle insertion.
• To improve the steerability and precision of flexible needle insertion systems.

Main Methods:

• An algorithm was developed to align the entire needle shaft using torque measurements at the base.
• The algorithm employs intermediate base rotations to correct for angular deviations.
• Experimental validation was conducted using angle sensors to measure needle orientation throughout the tissue.

Main Results:

• The compensation algorithm significantly reduced the lag between the needle base and tip angles.
• Angle discrepancies along the needle shaft were decreased by up to 88%.
• Minimal residual torque was observed, indicating successful needle alignment.

Conclusions:

• The developed torque-based algorithm effectively compensates for friction-induced errors in flexible needle insertion.
• This method enhances the precision and control of flexible needles, enabling more accurate tissue targeting.
• The findings have significant implications for improving robotic surgery and interventional procedures.