A novel curvature-controllable steerable needle for percutaneous intervention

Area of Science:

• Medical Robotics
• Minimally Invasive Surgery
• Biomedical Engineering

Background:

• Flexible steerable robotic needles are crucial for percutaneous interventions.
• Current methods, like the duty-cycle algorithm with fixed-angled bevel-tip needles, face challenges in minimizing tissue damage and achieving sufficient curvature.
• These limitations hinder the widespread adoption of steerable needle technology.

Purpose of the Study:

• To develop a novel steerable flexible needle capable of changing curvature without axial rotation.
• To achieve a larger radius of curvature for enhanced controllability.
• To reduce potential damage to surrounding tissues during percutaneous interventions.

Main Methods:

• A novel curvature-controllable steerable needle was designed, comprising a cannula and a bevel-tipped stylet.
• Needle curvature is controlled via a 'control offset' between the bevel-tip and cannula, minimizing the need for whole-body needle rotation.
• A duty-cycle algorithm was used minimally to achieve a larger radius of curvature.

Main Results:

• The first prototype (0.46 mm outer diameter) was successfully fabricated and tested.
• Maximum curvatures achieved were 0.008 mm⁻¹ (6 wt% gelatin), 0.0139 mm⁻¹ (10 wt% gelatin), and 0.0038 mm⁻¹ (cow liver).
• A linear relationship was observed between the needle's curvature and the control offset.

Conclusions:

• The proposed novel steerable needle design offers improved curvature control and reduced rotational movement.
• The observed linear relationship between curvature and control offset provides a basis for future control algorithm implementation.
• This technology has the potential to enhance the safety and efficacy of percutaneous interventions.