Devices, systems, and methods using a steerable stylet and flexible needle

A stylet comprising:

• a flexible body;
• a steerable portion fixedly coupled to the flexible body, the steerable portion including a bend-resistive tip and a bendable section, the bendable section including a plurality of articulable segments and a plurality of joint pivots disposed between the plurality of articulable segments, wherein each joint pivot of the plurality of joint pivots intersects a central longitudinal axis of the steerable portion, wherein each articulable segment of the plurality of articulable segments is linked by a corresponding actuation cable of a plurality of actuation cables, wherein the bend-resistive tip includes a distal end and a proximal end, and wherein the plurality of actuation cables extend through the flexible body of the stylet and terminate distal to the proximal end of the bend-resistive tip of the steerable portion of the stylet;
• and
• a sensor element extending through the flexible body,
• wherein the stylet is movable within a lumen of an elongate instrument between a retracted condition in which the steerable portion is retracted within the elongate instrument and an extended configuration in which the steerable portion at least partially extends from the elongate instrument.