Manual Active Cannula Deployment: Experimental Accuracy Evaluation in Free Space

Liver tumor ablation requires the ability to accurately target multiple sites with an ablator tip using an insertion device. A minimally invasive approach using straight needles usually requires multiple insertions which damage the liver capsule and cause bleeding. We propose a multi-tube steerable cannula to enable access to multiple internal points from a single liver capsule entry point. The cannula is made of concentric tubes of superelastic Nitinol which can translate and rotate with respect to one another in order to drive the tip to a desired target, through a curved path. Deployment of the cannula from an insertion unit can be entirely automated [1], teloperated [2], or done manually [3]. For a first assessment towards human clinical trials, we built a manual insertion unit that is completely sterilizable. In this paper we evaluate the achievable accuracy of this manual actuation unit for deploying the ablator tip to a desired Cartesian position in free space.