What is described is a minimally invasive system comprising an elongate instrument and a stylet slidably disposed within the lumen of the elongate instrument. The instrument includes a flexible proximal portion fixedly coupled to a rigid distal portion, and a lumen extending from a proximal end to a distal end through the flexible proximal portion and the rigid distal portion and defining a longitudinal axis of the instrument. The stylet includes a flexible body fixedly coupled to a steerable portion and a sensor element extending through the flexible body. The stylet is movable within the instrument between a retracted condition in which the steerable portion is retracted within the instrument and an extended configuration in which the steerable portion at least partially extends from the rigid distal portion of the instrument.