By designing needles out of Nitinol, a highly flexible metal, the achievable curvature of a needle is greatly increased. When used in conjunction with an asymmetric needle tip, which creates asymmetric forces on the needle when cutting tissue, needles have been created that can follow curved trajectories. This will one day allow surgeons to 'drive' a needle to some point in the human body while avoiding obstacles and dangerous zones along the way. Using some past work on modeling the needle trajectory, I developed a human teleoperation interface so that a surgeon could perform the procedure.
Using a generic haptic device called the Freedom6s I developed a mapping between its joints, and the needle steering robot. Attach:f6sanddriver.jpg Δ Δ | A Freedom6s haptic device (right) and our needle steering device (left). The degrees of freedom that were mapped between the two are shown drawn on the images.
When combined with a graphical user interface and several different control mappings, users were very good at driving the needle around obstacles and to targets.
Attach:needlegui.jpg Δ Δ | The GUI provided to a surgeon who is using a steerable needle. They are provided a real-time image of the needle-tissue state, a dial gauge to display their current rotational angle, and a meter to tell them how deep they are within the tissue.
A quick video of a needle insertion