Trajectory Optimization for Dynamic Needle Insertion

Needle based intervention procedures are a common minimally invasive surgical technique. In many of these procedures, the needle can be considered rigid and the tissue deforms and displaces substantially as the needle is advanced to its target. An energy based, fracture mechanics approach is presented to show that the velocity dependence of tissue properties can reduce tissue motion with increased needle velocities. In-vitro test results on porcine heart samples show that the force required to initiate cutting reduces with increasing needle velocity up to a critical speed, above which, the rate independent cutting force of the underlying tissue becomes the limiting factor. In-vivo tests show increased needle speed results in reduced force and displacement for needle insertion into the heart. Results indicate that automated insertion could substantially improve performance in some applications.