A Flexure-Based Steerable Needle: High Curvature With Reduced Tissue Damage

In the quest to design higher curvature bevel-steered needles, kinked bevel-tips have been one of the most successful approaches yet proposed. However, the price to be paid for enhancing steerability in this way has been increased tissue damage, since the prebent tip cuts a local helical path into tissue when axially rotated. This is problematic when closed-loop control is desired, because the controller will typically require the needle to rotate rapidly, and it is particularly problematic when duty cycling (i.e., continual needle spinning) is used to adjust curvature. In this paper, we propose a new flexure-based needle tip design that provides the enhanced steerability of kinked bevel-tip needles, while simultaneously minimizing tissue damage.