Robot-assisted automatic insertion of steerable needles with closed-loop imaging feedback and intraoperative trajectory replanning

• We propose a robot-assisted approach for steering beveled flexible needles.
• It combines closed-loop feedback with intraoperative path replanning for robustness.
• The needle trajectory curvature is adjusted using a duty-cycled rotation strategy.
• The method is capable of dealing with obstacles and dynamic workspaces.
• Simulations and in vitro experiments attested the viability of our robotic system.

This paper presents a robot-assisted approach for automatic steering of flexible beveled needles in percutaneous procedures. The method uses duty-cycled rotation of the needle to perform insertion with arcs of adjustable curvature, and combines closed-loop imaging feedback with an intraoperative motion replanning strategy to compensate for system uncertainties and disturbances. Differently from previous solutions, the closed-loop replanning strategy is suitable for dynamic scenes since it does not rely on prebuilt roadmaps. Indeed, simulations of a needle insertion under the presence of moving obstacles and target confirmed the advantage of the approach with final mean error of 0.34 mm to the desired goal. Also, our new path planner presented 143% higher success rate and was more than 377% faster than the previous developed algorithm. The proposed system was also physically implemented using a nitinol needle prototype attached to a robotic manipulator, and validated with in vitro tests performed in closed-loop with imaging feedback from a camera. In such tests, the needle tip should reach a desired target in a tissue phantom, while deviating from obstacles and compensating for modeling uncertainties such as tissue inhomogeneity and imprecise needle tip tracking. The successful obstacle avoidance and mean insertion precision of 1.34 mm during the experimental trials attested the viability of our method and presented the intraoperative replanning approach as a strong candidate for future use in automatic needle steering solutions.