Design and control considerations for safe needle steering in brain tissue

This paper presents a preliminary investigation of numerous design and control parameters of bevel-tipped needles with regard to their effect on safety of brain tissue during insertion. The needle is designed for use with a control method developed in our laboratory that provides proportional control of path curvature via duty-cycled rotation. Parameters investigated include needle radius, bevel angle, bevel tip fillet radius, insertion velocity, and rotational velocity. Design parameters are investigated in terms of their effect on stress, strain, and strain rate of brain tissue. Based on the effects of the preliminary investigation, a safe needle design is selected and demonstrated in a three-dimensional simulation of closed-loop control of needle steering via duty-cycled rotation in a deep brain stimulation application.