Performance of the smart surgical micro-drill for cochlear implantation

Robotic surgery has made its mark as a precise means of tool deployment in surgical procedures since the late 1980s (Drake 1991, Taylor 1990). There is always a dilemma associated with the perception of interaction with the tissue at the tool point. This is particularly true in minimal access procedures and where the tissue deflects or deforms significantly. There is also the need to harness the precision and consistency that can be achieved in surgery in such applications by using robotics without introducing unnecessary complexity or costs. The robotic surgical micro-drill is moving surgical robotics in this direction. It is a generic technique for controlling penetration with precision in flexible tissues. The technique needs only standard cutting tools and the device uses only a few coupled sensory signals to discriminate the different conditions and states of tissues. Small robots of this type have a future in surgery and demonstrate the power of the mechatronics philosophy leading to a pragmatic solution that is appropriate to a complex environment in practice. In this paper, the approach taken to apply the drill to cochleostomy is challenging and offers considerable benefit over other forms of penetrating the bone tissue of the cochlea. It is shown that the technique is both tolerant to anatomical variation in tissues and to the trajectory taken with respect to the tissues. This is important as greater tolerance leads to greater consistency in the drilling result and performance of the electrode. There is also potential for reduced complications.